Past Public Meetings

The Diablo Canyon Independent Safety Committee Notice of Public Meeting

  THE DIABLO CANYON INDEPENDENT SAFETY COMMITTEE
(https://www.dcisc.org)
    NOTICE OF PUBLIC MEETING

NOTICE IS HEREBY GIVEN that on June 10-11, 2025, at the Avila Lighthouse Suites Point San Luis Conference Facility located at First & San Francisco Streets, Avila Beach, California, a public meeting will be held by the Diablo Canyon Independent Safety Committee (DCISC) in five separate sessions, at the times indicated, to consider the following matters.

You may also participate in the DCISC's public meeting in real-time by accessing the Zoom webinar meeting via the weblink or meeting ID given below or by using any of the phone numbers provided. Webinar attendees can make oral comments or ask questions of the Committee Members during the webinar meeting by using the "Raise Your Hand" feature or by pressing *9 on your telephone keypad if joining by telephone only. If you are unable to attend or participate in real-time, you may email to dcsafety@dcisc.org with the subject line "Public Comment Agenda Item #___" (insert the item number relevant to your comment) or "Public Comment - Non Agenda Item." Comments will be reviewed and distributed before the meeting if received by noon on Monday, June 9, 2025. Comments received after that will be addressed during the item or at the end of the meeting. Each session will include comments by the Committee Members and an opportunity for members of the public to address remarks to the Committee.

Zoom Webinar Meeting ID: 818 1769 2903
Please click the link below to join the webinar
https://us02web.zoom.us/j/81817692903

Zoom Webinar Meeting Telephone Only Participation: Phone one-tap: +1 4086380968,,81817692903# US (San Jose); +1 6694449171,,81817692903# US; Join via audio:+1 408 638 0968 US (San Jose); +1 669 444 9171 US; +1 669 900 6833 US (San Jose); +1 253 215 8782 US (Tacoma); +1 346 248 7799 US (Houston); +1 719 359 4580 US; +1 253 205 0468 US; +1 689 278 1000 US; +1 301 715 8592 US (Washington DC); +1 305 224 1968 US; +1 309 205 3325 US; +1 312 626 6799 US (Chicago); +1 360 209 5623 US; +1 386 347 5053 US; +1 507 473 4847 US; +1 564 217 2000 US; +1 646 876 9923 US (New York); +1 646 931 3860 US.

1.         Morning Session - (06/10/2025) - 9:00 a.m.  Opening comments and remarks; receive public comments and communications to the Committee; receive informational presentations requested by the Committee of PG&E related to plant safety and operations, including (1) State of the Plant including organizational changes, activities, power history, equipment issues, human performance issues since the DCISC's February 2025 public meeting, (2) results of Refueling Outage 1R25 including refueling, maintenance activities, major projects and inspections, preparations for Refueling Outage 2R25 including the scope, schedule, and major projects, (3) update on the removal of surveillance Capsule B during 1R25, (4) overview of the Engineering Department organization, staffing, roles, performance and improvement initiatives and project planning/approvals, (5) update on the status of NRC Performance Indicators, Licensee Event Reports, NRC Inspection Reports and Notices of Violation, issues raised by NRC inspectors, open compliance issues, status of cross-cutting issues matrix, current and future license amendment requests and other regulatory issues

2.         Afternoon Session - (06/10/2025) - 1:15 p.m.  Committee member comments; receive public comments and communications to the Committee; Committee discussion of recent Presidential Executive Orders regarding U.S. commercial nuclear power facilities and monitoring and future inquiry into the effect on DCPP; review of future meeting dates, documents provided to the committee, discussion concerning correspondence exchanged including concerning recent media inquiries and Unit 1 reactor pressure vessel integrity; report by Committee Technical Consultant on and approval of fact finding visits conducted on March 19-20 and March 28, 2025; and review of the Minutes of February 19-20, 2025 public meeting.

            3.         Evening Session - (06/10/2025) - 5:00 p.m. Committee member comments; receive the results of the DCISC's review of Dr. Peter Bird's concerns regarding the seismic hazard for DCPP as evaluated by Seismic Review Team (SRT) Consultants Dr. Tom Jordan, Dr. Mike Oskin, and Dr. Scott Marshall, and receive public comments and communications to the Committee.

            4.         Morning Session - (06/11/2025) - 9:00 a.m.  Committee member comments; further discussion of future DCISC actions, initiatives, or recommendations based on the results of review by Drs. Jordan, Oskin and Marshall of Dr. Peter Bird's concerns regarding the seismic hazard for DCPP; review of Open Items List and status of recommendations; presentation by the NRC Senior Resident Inspector for DCPP on the NRC's annual assessment of DCPP end-of cycle performance for calendar year 2024 and receive public comments and communications.

            5.         Afternoon Session - (06/11/2025) - 1:15 p.m.  Committee member comments; receive public comments and communications to the Committee; election of Chair and Vice-Chair for the July 1, 2025 - June 30, 2026 term, Committee discussion on status of governmental agency interactions, the California Public Utilities Commission's pending Decision in R.23-01-007 on Phase 2 issues including future funding for Committee activities and other financial matters, regulatory and administrative matters including review of a proposed Fourth Restatement of the Committee's Charter, consideration of revised and new Committee Policies, report by Committee Technical Consultant on, and approval of, fact finding visits conducted on April 28-29 and May 7-8, 2025; and wrap-up discussion by Committee members and confirmation of future site visits, study sessions and public meetings.

The meeting will be webcast in real time at: http://www.slo-span.org/ and through https://www.dcisc.org. The specific meeting agenda will be available at least 72-hours before the meeting and the agenda together with the staff reports and materials regarding the above meeting agenda items will be available for public review commencing Friday, June 6, 2025, at the Special Collections and Archives Department of the Cal Poly Library in San Luis Obispo and online at www.dcisc.org. For further information regarding the public meeting, please contact Robert Rathie, Committee Assistant Legal Counsel, P.O. Box 4253, Carmel-by-the-Sea, CA 93921-4253; telephone: 1-800-439-4688 or read the agenda on line by visiting the Committee's website at www.dcisc.org.

Dated: May 28, 2025.

DCISC Agenda for the next Public Meeting

DIABLO CANYON
INDEPENDENT SAFETY COMMITTEE ("DCISC")
(www.dcisc.org)

Committee Members:

Robert J. Budnitz Najmedin Meshkati Per F. Peterson

*  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  *  * * * * * * * * *

Tuesday & Wednesday, June 10-11, 2025
Point San Luis Conference Room
Avila Lighthouse Suites
First & San Francisco Streets, Avila Beach, California

PUBLIC MEETING AGENDA

This public meeting will be webcast in real time at:
http://www.slo-span.org/local_webcast/DCISC/stream_index.htm and through https://www.dcisc.org
This meeting is also being produced as a Zoom webinar by AGP Video Inc. and will be broadcast subsequently on San Luis Obispo local government access television, Channel 21.

Zoom Webinar Meeting ID: 818 1769 2903

Please click the link below to join the webinar
https://us02web.zoom.us/j/81817692903

Zoom Webinar Meeting Telephone Only Participation: Phone one-tap: +1 4086380968,,81817692903# US (San Jose); +1 6694449171,,81817692903# US; Join via audio:+1 408 638 0968 US (San Jose); +1 669 444 9171 US; +1 669 900 6833 US (San Jose); +1 253 215 8782 US (Tacoma); +1 346 248 7799 US (Houston); +1 719 359 4580 US; +1 253 205 0468 US; +1 689 278 1000 US; +1 301 715 8592 US (Washington DC); +1 305 224 1968 US; +1 309 205 3325 US; +1 312 626 6799 US (Chicago); +1 360 209 5623 US; +1 386 347 5053 US; +1 507 473 4847 US; +1 564 217 2000 US; +1 646 876 9923 US (New York); +1 646 931 3860 US.

PARTICIPATION

You may participate in the DCISC's public meeting in person or in real-time by accessing the Zoom webinar meeting via the weblink and the webinar ID given above or by calling any of the phone numbers provided at the top of this agenda. Instructions on how to access, view and participate in remote meetings are also provided by visiting the DCISC's home page at https://www.dcisc.org/.  Attendees can make oral comments or ask questions of the Committee Members during the webinar meeting by using the "Raise Your Hand" feature or by pressing *9 on your telephone keypad if joining by telephone only. If you are unable to participate in real-time, you may email to dcsafety@dcisc.org with the subject line "Public Comment Item#___" (insert the item number relevant to your comment) or "Public Comment - Non-Agenda Item."  Comments will be reviewed and distributed before the meeting if received by Noon on Monday, June 9, 2025. Comments received after that will be addressed during the item and/or at the end of the meeting. All comments received will be read into and become part of the record, subject to a time limit determined by the presiding officer. Subject to the requirements to publish an agenda in advance, the Committee will have the option to modify its actions on items based on comments received.

In accordance with the Bagley-Keene Open Meeting Act (CA Govt. Code §§11120 et seq.) and the Committee's Policies, for each item on the Agenda the Committee reserves the right, at the discretion of the presiding officer, to limit the total amount of time allocated for public comment on particular issues and/or for each individual public commenter. A time limit for each public commenter will be announced during every session. For any public commenter(s) who previously requested and at the discretion of the presiding officer were granted additional time an announcement will be made at the beginning of the session. Public commenters will not be recognized more than once during public comments on matters not on the agenda or during consideration of an agenda item, but may be called upon subsequently to respond to questions from the Committee. Public commenters may not cede time to other public commenters.

Morning Session - 06/10/2025 - 9:00 A.M.

I    CALL TO ORDER - ROLL CALL

II  INTRODUCTIONS AND COMMITTEE MEMBER COMMENTS

ADVISEMENT
The Committee may consider at any time requests to change the order of a listed agenda item.  Information     distributed to the Committee at a public meeting becomes part of the public record of the DCISC. A copy of     written material, pictures, etc., must be provided to the Committee's Legal Counsel for this purpose. Those persons     making public comments are requested and encouraged to provide copies of any prepared written materials or     slides they intend to use in their remarks to the Legal Counsel's office prior to addressing remarks to the     Committee and in sufficient time such that they may be distributed. Correspondence received and sent by the     Committee is on file with the Office of the DCISC Legal Counsel and copies are available upon request.  Devices     for attendees who may be hearing impaired are available upon request. The meeting will be webcast in real time.

III PUBLIC COMMENTS AND COMMUNICATIONS

Anyone wishing to address the Committee on matters not appearing on the Agenda may do so at this time. (The public may comment on any matter listed on this morning's agenda immediately following the time the matter is considered by the Committee.) There will be a time limit for each topic and/or speaker as designated by the presiding officer as announced at the beginning of this session. No action will be taken by the Committee on matters brought up under this item, but they may be referred to staff for further study, response or action.

IV  INFORMATION ITEMS BEFORE THE COMMITTEE

1. Informational Presentations Requested by the Committee of PG&E:

1. State of the Plant Update including Organizational Changes, Significant Past and Future Plant Activities, Power History, Significant Equipment Issues, Significant Human Performance Issues,  and Other Station Activities since the DCISC's February 2025 Public Meeting.
2. Results of Refueling Outage 1R25, Including Refueling, Major Maintenance Activities, Implementation of Major Projects and License Inspections.  Preparations for Refueling Outage 2R25, Including the Planned Scope, Schedule, and Implementation of Major Projects.
3. Update on the Removal of Reactor Embrittlement Specimen Capsule B during Refueling Outage 1R25.
4. Overview of and Update on Engineering Department Organization, Staffing, Roles, Performance History and Improvement Initiatives, and Project Planning/Approvals.
5. Update on the Status of NRC Performance Indicators, Licensee Event Reports, NRC Inspection Reports and Notices of Violation, Issues Raised by NRC Resident Inspectors, Open Compliance Issues, Status of Cross-Cutting Issues Matrix, Current and Future License Amendment Requests, and Other Significant Regulatory Issues/Requests.

V    ADJOURN MORNING MEETING

Afternoon Session - 06/10/2025 - 1:15 P.M.

VI  RECONVENE FOR AFTERNOON MEETING

VII  COMMITTEE MEMBER COMMENTS

VIII PUBLIC COMMENTS AND COMMUNICATIONS

Anyone wishing to address the Committee on matters not appearing on the Agenda may do so only at this time. (The public may comment on any matter listed on this afternoon's agenda immediately following the time the matter is considered by the Committee.) There will be a time limit for each topic and/or speaker as designated by the presiding officer as announced at the beginning of this session. No action will be taken by the Committee on matters brought up under this item, but they may be referred to staff for further study, response or action.

IX  DISCUSSION, DIRECTION AND ACTION, AS APPROPRIATE, BY THE COMMITTEE, CONSULTANTS & COUNSEL

1. Committee Discussion of Recent Presidential Executive Orders Regarding Regulation and Licensing  of U.S. Commercial Nuclear Power Facilities and Committee Path Forward for Monitoring and Future Inquiry into the Effect on DCPP.
2. Review of Future Meeting Dates; ; Documents Provided to the Committee; Discussion, Assessment and Direction Concerning Correspondence Exchanged  Including Concerning Recent Media Inquiries, and Unit 1 Reactor Pressure Vessel Integrity.

X  TECHNICAL CONSULTANT REPORTS; RECEIVE, APPROVE AND AUTHORIZE TRANSMITTAL OF FACT-FINDING REPORTS TO PG&E

3. Consultant Richard McWhorter:
   Fact-finding Topics; Report on and approval of March 19-20, 2025, Fact Finding Report.
4. Consultant Richard McWhorter:Fact-finding Topics; Report on and approval of March 28, 2025, Fact Finding Report.

XI  ACCEPTANCE OF MINUTES

Minutes of February 19-20, 2025, Public Meeting. 2025.

Accept

XII  ADJOURN AFTERNOON MEETING

Evening Session - 06/10/2025 - 5:00 P.M.

XIII    RECONVENE FOR EVENING MEETING

XIV    COMMITTEE MEMBER COMMENTS

XV    INFORMATION ITEM PRESENTED BY THE COMMITTEE

6. Receive Results of the DCISC's Review of Dr. Peter Bird's Concerns Regarding the Seismic Hazard for DCPP as Evaluated by Seismic Review Team (SRT) Consultants Dr. Tom Jordan, Dr. Mike Oskin, and Dr. Scott Marshall.

XVI PUBLIC COMMENTS AND COMMUNICATIONS

The public may comment on the matter listed on this evening's agenda immediately following the time the matter is considered by the Committee. Anyone wishing to address the Committee on matters not appearing on the Agenda may do so following comments on the matter on the agenda.. There will be a time limit for each topic and/or speaker as designated by the presiding officer as announced at the beginning of this session. No action will be taken by the Committee on matters brought up under this item, but they may be referred to staff for further study, response or action.

XVII    ADJOURN EVENING MEETING

Morning Session - 06/11/2025 - 9:00 A.M.

XVIII    RECONVENE FOR MORNING MEETING

XIX    COMMITTEE MEMBER COMMENTS

XX   DISCUSSION, DIRECTION AND ACTION, AS APPROPRIATE, BY THE COMMITTEE, CONSULTANTS & COUNSEL (Cont'd.)

7. Further Discussion of Future DCISC Actions, Initiatives, or Recommendations Based on the Results of the DCISC's Review by Drs. Jordan, Oskin and Marshall of Dr. Peter Bird's Concerns Regarding the Seismic Hazard for DCPP.
8. Review of Open Items List and Status of Recommendations.

XXI    INFORMATION ITEM PRESENTED BY THE NRC SENIOR RESIDENT INSPECTOR FOR DIABLO CANYON POWER PLANT

Presentation by the NRC's Senior Resident Inspector for DCPP, Mr. Mahdi Hayes, on the NRC's Annual Assessment of DCPP's End-of Cycle Performance for Calendar Year 2024.

XXII    PUBLIC COMMENTS AND COMMUNICATIONS

Anyone wishing to address the Committee on matters not appearing on the Agenda may do so at this time. (The public may comment on any matter listed on this morning's agenda immediately following the time the matter is considered by the Committee.) There will be a time limit for each topic and/or speaker as designated by the presiding officer as announced at the beginning of this session. No action will be taken by the Committee on matters brought up under this item, but they may be referred to staff for further study, response or action.

XXIII  ADJOURN MORNING MEETING

Afternoon Session - 06/11/2025 - 1:15 P.M.

XXIV  RECONVENE FOR AFTERNOON MEETING

XXV  COMMITTEE MEMBER COMMENTS

XXVI  PUBLIC COMMENTS AND COMMUNICATIONS

Anyone wishing to address the Committee on matters not appearing on the Agenda may do so only at this time. (The public may comment on matters listed on this morning's agenda immediately following the time the matter is considered by the Committee.) There will be a time limit for each topic and/or speaker as designated by the presiding officer as announced at the beginning of this session. No action will be taken by the Committee on matters brought up under this item, but they may be referred to staff for further study, response or action.

XXVII   ACTION ITEM

Nomination and Election of Chair and Vice-Chair for the July 1, 2025 - June 30, 2026 Term

Discussion/Action

XXVIII    DISCUSSION, DIRECTION AND ACTION, AS APPROPRIATE, BY THE COMMITTEE, CONSULTANTS & COUNSEL (Cont'd.)

10. Status of Governmental Agency Interactions, Response to the California Public Utilities Commission Pending Decision in R.23-01-007, Decision on Phase 2 Issues including Future Funding for Committee Activities and other Financial Matters, Regulatory and Administrative Matters including Review of a Proposed Fourth Restatement of the Committee's Charter, Consideration of Revised and New Committee Policies, and Other Committee Discussions.

XXIX  TECHNICAL CONSULTANT REPORTS; RECEIVE, APPROVE AND AUTHORIZE TRANSMITTAL OF FACT-FINDING REPORTS TO PG&E (Cont'd.)

11. Consultant Richard McWhorter:
    Fact-finding Topics; Report on and approval of April 28-29, 2025, Fact Finding Report.
12. Consultant Richard McWhorter:
    Fact-finding Topics; Report on and approval of May 7-8, 2025, Fact Finding Report.

XXX  CONCLUDING REMARKS & DISCUSSION BY COMMITTEE MEMBERS OF FUTURE DCISC ACTIVITIES

13. Future Actions by the Committee.
14. Further Information to Obtain/Review.
15. Confirmation of Future Site Visits, and Public Meetings.

XXXI ADJOURNMENT OF THE ONE HUNDRED AND ELEVENTH PUBLIC MEETING

The DCISC's policy is to schedule its public meetings in locations that are accessible to people with disabilities and to remain in compliance with state guidelines on communicable disease prevention. Hand sanitizers and face coverings are available in the meeting room. The Avila Lighthouse Suites Point San Luis Conference Room is a wheelchair accessible facility. A person who needs a disability-related accommodation or modification in order to participate in the meeting may make a request by contacting the DCISC office (in CA 800-439-4688 or (831) 647-1044) or by sending a written request to the DCISC office at P.O. Box 4523, Carmel-by-the-Sea, CA 93921-4523. Providing your request at least five business days before the meeting will help ensure availability of the requested accommodation.

M I N U T E S
of the
DIABLO CANYON INDEPENDENT SAFETY COMMITTEE'S
JUNE 10-11, 2025, PUBLIC MEETING
[As  approved at the October 22-23, 2025, Public Meeting.]

Tuesday & Wednesday
June 10-11, 2025
Avila Beach, California
Also conducted as a Zoom Webinar

Notice of Meeting.

            A legal notice of the public meeting was published in the San Luis Obispo Tribune and a y advertisement was published in the New Times, both local newspapers of general circulation, and mailed and emailed to the media and those persons on the Committee's mailing list. The meeting agenda, the complete agenda packet for the meeting, the informational presentations made during the meeting, together with the fact finding reports and the Seismic Review Team's report to be considered during the meeting were all posted on the Committee's website prior to the meeting. The meeting agenda contained information on how to access the webinar using a computer, cellphone or a telephone. This in-person meeting was also produced as a Zoom webinar by AGP Video, Inc. and was webcast live on SLO-SPAN at http://www.slo-span.org and through https://www.dcisc.org and was subsequently broadcast on San Luis Obispo, California, local government access television Channel 21. A supply of hand sanitizers and face coverings was available at all times in the meeting room.

I           CALL TO ORDER - ROLL CALL

            The June 10, 2025, public meeting of the Diablo Canyon Independent Safety Committee (DCISC or sometimes the Committee), the one hundred and eleventh public meeting of the Committee, was called to order by Committee Chair Dr. Per F. Peterson at 9:00 a.m. Dr. Peterson conducted roll call and briefly reviewed the professional backgrounds and appointment to the DCISC for each of his fellow Members, Dr. Najmedin Meshkati, the appointee of the Chair of the California Energy Commission and a Professor of Civil and Environmental Engineering at the University of Southern California with expertise in human factors and the reliability of complex systems, and Dr. Robert J. Budnitz, the appointee of the California Attorney General and a physicist and expert in nuclear reactor safety and seismic response. Dr. Budnitz then briefly reviewed Dr. Peterson's professional background and reported Dr. Peterson serves on the DCISC as the appointee of the Governor and is a Professor at the University of California at Berkeley in the Nuclear Engineering Department and Dr. Peterson is also a co-founder and Chief Nuclear Officer for Kairos Power, a small modular reactor company.

Present:	Committee Member Robert J. Budnitz Committee Member Najmedin Meshkati Committee Member Per F. Peterson
Absent:	None

II         INTRODUCTIONS

            Dr. Peterson introduced and briefly reviewed the professional backgrounds and history with the Committee of the Committee's Technical Consultants and Assistant Legal Counsel present: Technical Consultants Mr. Richard D. McWhorter Jr. Mr. R. Ferman Wardell, P.E., and Dr. Andrew C. Kadak, and Assistant Legal Counsel Mr. Robert W. Rathie.

            Dr. Peterson then introduced Ms. Brandy Lopez, Strategic Initiatives Licensing Principal at Pacific Gas & Electric Company's (PG&E) Diablo Canyon Power Plant (DCPP or sometimes the plant). Dr. Peterson remarked that Ms. Lopez provides key assistance to the DCISC on behalf of PG&E and she is the DCPP principal liaison with the DCISC in coordinating the Committee's activities, providing information, and facilitating the Committee's public meetings and the frequent fact-finding visits to the plant site conducted by a single member and one of the technical consultants. Dr. Peterson observed that there are several other independent reviewers of DCPP including PG&E's Nuclear Safety Oversight Committee (NSOC), the Institute of Nuclear Power Operations (INPO) and the World Association of Nuclear Operations (WANO).

Mr. Rathie reported this meeting is being recorded, livestreamed and broadcast on the internet as a Zoom webinar and he welcomed and introduced the technicians for AGP Video who provide these vital components of the Committee's public meetings.

III        PUBLIC COMMENTS AND COMMUNICATIONS

            Dr. Peterson remarked that many of the topics the Committee identifies for its investigations emerge from requests or questions posed by members of the public during the Committee's public meetings. Dr. Peterson then requested Mr. Rathie to review the guidance on making public comments to the Committee. Mr. Rathie reminded the members and consultants of the importance of exercising discipline in making and responding to comments so that an accurate transcript may be produced. He then reviewed the rules adopted to entertain public comment during each session of this meeting on an equitable basis for all as follows:

→        Speakers should come to the podium and identify themselves.

→        Speakers will be recognized by the Chair in order, first from among those present in the    room and then from among those attending virtually.

→        Remarks will be limited to four minutes, but this may be varied for each session,

→        Comments from public officials may be taken before those of members of the general public.

→        Speakers may not cede their time to other speakers.

→        Groups may be asked to appoint a spokesperson.

→        Each speaker may only address the Committee once under either time for items not on the agenda, but within the Committee's subject matter jurisdiction (i.e., the operational safety of DCPP) or when a matter listed on the agenda is heard.

→        The DCISC Chair reserves the right to stop any speaker if he or she believes the speaker   is out of order.

→        The Committee reserved the right to modify the rules in the interest of conducting an effective meeting including granting extra time to certain speakers upon request,

→        Writings used in conjunction with remarks should be provided to the Committee's Legal Counsel.

→        Email comments received will be read into the record subject to a time limit.

Mr. Rathie announced that there will be a change to the agenda, which is to defer the presentation on the NRC Performance Indicators and plant regulatory performance from the first to the second day and to then consider the status of governmental agency interactions and other matters at the end of this morning session. Mr. Rathie then welcomed and recognized Dr. Deb Luchsinger of Preferred Licensing Services who was present for this meeting in her role as a consultant to the California Department of Water Resources (DWR).

The Chair then invited any member of the public who wished to address remarks to the Committee on items not appearing on the agenda for the public meeting to do so at this time.

            Dr. Gene Nelson, representing the group Californians for Green Nuclear Power was recognized. Dr. Nelson provided written comments and stated his comments were motivated by events which occurred on April 28, 2025, on the Iberian Peninsula when a large-scale electrical blackout occurred following the failure of some renewable energy generation plants, resulting in all the affected nuclear units promptly tripping.[1] He expressed his concern with what he described as the political influence in favor of creating large amounts of photovoltaic and wind generation such that California may be at risk of an Iberian-type blackout. Dr. Nelson remarked the Iberian event resulted in nine deaths and $1 billion in economic damage due to lost productivity. He observed that data, for which he displayed a graph from the California Independent System Operator (CA ISO),[2] on the high ratio of inverter-based resources to those contributing to synchronous grid inertia which he stated indicates a much greater level of penetration in California than on the Iberian Peninsula. He reported the North American Electric Reliability Corporation (NERC) issued a level three alert on May 20, 2025. He stated he believes these concerns warrant the Committee's review as a widespread CA ISO outage will likely cause a Diablo Canyon plant trip. Consultant McWhorter remarked the Committee has an item on its Open Items List to periodically review the transmission system and has had discussions with DCPP on current statistics for grid stability. Dr. Peterson agreed it may be worthwhile to check on any lessons learned from the Iberian blackout experience.

IV        INFORMATION ITEMS BEFORE THE COMMITTEE

            Dr. Peterson requested Mr. Philippe Soenen, DCPP Director of Strategic Initiatives, to introduce the first presentation requested by the Committee of PG&E. Mr. Soenen then introduced DCPP Station Director Mr. Justin Rogers to make that presentation and Mr. Soenen reported that Mr. Rogers leads a team of more than 650 nuclear professionals in the Operations, Maintenance, Chemistry, Radiation Protection organizations and in other safety organizations. Mr. Rogers began his career at DCPP in 2013, received a Senior Reactor Operator License in 2016 and worked in increasing positions of responsibility in the Training and Outage Management organizations. Mr. Rogers is a veteran of the U.S. Navy and holds a Bachelor of Science Degree in Nuclear Energy Engineering Technology from Thomas Edison State University.

State of the Plant Update Including Organizational Changes, Significant Past and Future Plant Activities, Power History, Significant Equipment Issues, Significant Human Performance Issues, and Other Station Activities since the DCISC's February 2025 Public Meeting.

            Mr. Rogers reported Unit 1 and Unit 2 are both presently operating safely at 100% power and all NRC Performance Indicators are currently in Green[3] status. He remarked that two resident inspectors assigned by the NRC are on the site full time and DCPP continues to perform in the top tier in the industry, that is, within Column One[4] of the NRC Reactor Oversight Process (ROP) Action Matrix.

Mr. Rogers reviewed the power history/load profile for both units and he reported for Unit 1 there were four reductions in power for circulating water tunnel cleaning (i.e., "pick and dredge") activities which were performed during off-peak demand hours on weekends. Refueling outage 1R25 (the twenty-fifth refueling outage for Unit 1) was conducted and completed in April-May 2025. For Unit 2 a pick and dredge was performed in March 2025. In response to Consultant McWhorter's observation Mr. Rogers reported that pick and dredge activities are now of shorter duration and the plant has continued to look for efficiencies, including minimizing bio growth and testing various coatings to further minimize the time required for pick and dredge. At the present time, one tunnel cleaning is required between refueling cycles for each unit.

            Mr. Rogers remarked that on May 7, 2025, Unit 1 celebrated 40 years of commercial operation. He then reviewed upcoming events as follows:

→        June 1-7 - NRC Biennial Requalification (BRQ) Inspection

→        June 23-26 - Nuclear Safety Oversight Committee (NSOC) Visit

→        July 6-12 & 20-26 - NRC Fire Protection Inspection

→        July 7-10 - Mid-Cycle Self-Assessment

→        August 10-16 - NRC Cyber Security Inspection

→        August 25-29 - Emergency Preparedness Program Inspection

→        Unit 2 planned Emergency Diesel Generator (EDG) Major Maintenance

→        Maintenance Outage Windows (MOWs) - EDG 2-1, June 8-17; EDG 2-3, July 3-22; EDG 2-2, August 17-26.

Mr. Rogers reported that over the next six weeks the twelve DCPP training programs will be evaluated by the Academy for Nuclear Training Accreditation Board which happens every six years. In response to Consultant Kadak's inquiry Mr. Rogers replied that the NSOC's focus is on areas of operations and maintenance. Mr. Soenen in response to Dr. Kadak's query stated he would need to follow up to provide information on the PG&E Corporation's Safety and Nuclear Oversight (SNO) Committee's present areas of focus. Dr. Budnitz remarked and Mr. Rogers concurred that the NSOC and the SNO Committee have different responsibilities and different oversight roles and he commented the SNO Committee, unlike the NSOC, is not made up of nuclear engineers.

Mr. Rogers closed his presentation by reporting there have been no plant leadership changes since the DCISC last met in February 2025 and the plant is generally fully staffed and at the present time has no vacant jobs that it is struggling to fill. In response to Dr. Meshkati's question Mr. Rogers reported the scope of 2R25 will be similar to that for 1R25 without the need to remove a reactor pressure vessel surveillance capsule during 2R25 and he confirmed the Unit 2 high-pressure turbine will have its rotating parts replaced. He reported there have been no failures of major equipment or human performance errors since the DCISC's last meeting in February 2025.

            Mr. Soenen then introduced DCPP's Director of Outage Management Mr. Erik Werner and he reported that Mr. Werner has more than 25 years' experience in nuclear plant engineering including in the Engineering, Operations, Training, Decommissioning Planning, and Outage Management organizations. Mr. Werner has been employed at DCPP for 18 years, holds a Senior Reactor Operator license and a Bachelor of Science Degree from the California Polytechnic State University at San Luis Obispo, California (Cal Poly).

Results of Refueling Outage 1R25, Including Refueling, Major Maintenance Activities, Implementation of Major Projects and License Inspections, Preparations for Refueling Outage 2R25, Including the Planned Scope, Schedule, and Implementation of Major Projects.

Mr. Werner reported 1R25 was completed during the Spring of 2025. It was a 40-day planned outage encompassing a scope including planned maintenance and project work, refueling activities, and several inspections required for license renewal. Approximately 1,000 temporary additional workers supported the safe completion of 1R25.

Mr. Werner reviewed the 1R25 key scope items as follows:

→        Primary[5] Side - Including large motor overhauls and reactor refueling.

→        Secondary Side -Including high-pressure turbine rotating element replacement and several valve inspections, and maintenance mainly in the Turbine Building.

→        Electrical – Including vital 4kV/480V Bus H preventative maintenance inspections and maintenance.

→        License Renewal - Including reactor pressure vessel surveillance Capsule B removal.

→        Projects - Including reactor vessel inspections and phase one of fuel transfer system equipment upgrades. In response to Consultant Kadak's questions Mr. Werner described the reactor vessel inspection as including robotic underwater inspection of the horizontal, circumferential, and vertical welds as well as the nozzle welds to ensure no flaws. Other subcomponents of the reactor pressure vessel were also inspected. Mr. Soenen stated he would take an action to determine whether a report through the In-Service Inspection Program could be made available for the Committee's review and Dr. Kadak remarked that it would be useful to compare that current report to previous in-service inspections.

Concerning outage goals for 1R25 Mr. Werner reported the safety goal for having no recordable injuries was not met due to one such injury having occurred when a contract worker fell from a ladder during practice for an evolution. He reported there is an open cause evaluation on this accident and immediate corrective action was taken to discuss how to prevent additional injuries of this nature. Mr. Werner reported there were no challenges to nuclear safety during 1R25 and adequate margins were maintained for defense-in-depth throughout the evolution of the outage. There were no human performance challenges. Outage duration was 35 days 22 hours, which was less than the goal set of 40 days and the dose goal of 31.325 person-rem was met by achieving the outage with 27.874 person-rem. Power ascension took just over three days, which met the five-day goal, and the goal of running for more than 90 days at maximum capable power is currently being monitored. In response to Consultant McWhorter's query Mr. Werner ascribed the good dose performance as being due to the recognition by DCPP and contractors' staffs that every entry into Containment or the Auxiliary Building, both radiologically controlled areas, matters and work planning can result in lower dose as well as remaining in low dose areas as much as possible. He reported there was not one particular scope item or individual activity that resulted in the lower dose, but rather it was due to across-the-board activities by individuals.

Mr. Werner then provided a summary of 2R25 which will take place during the fall of 2025. The 40-day planned outage will encompass a scope similar to 1R25 for planned maintenance and project work, refueling activities, and license renewal required inspections, but without the removal of a reactor pressure vessel surveillance capsule. Approximately 1,000 temporary additional workers will again support the safe completion of 2R25. The rotating elements of the Unit 2 high-pressure turbine will be replaced during 2R25. In response to Dr. Peterson's observation Mr. Werner agreed that certain opportunities are identified during the Unit 1 outages, which precede outages for Unit 2, and this allows the identifications of efficiencies and incorporation of lessons learned to improve performance during Unit 2 outages. In response to Dr. Meshkati's query Mr. Werner agreed there is the possibility that when the Unit 2 high-pressure turbine outer casing is opened conditions found could require extra work similar to the experience with Unit 1 in 1R25. He remarked that within the high-pressure turbine casing, other than the rotor replacement, the focus of the work is likely to be on clearances and steam flow path and he reported the plant is prepared to execute necessary work in response to any contingencies discovered with the high-pressure turbine work during 2R25.

In response to Consultant Kadak's request Mr. Werner identified the welding work on the high-pressure turbine, the effect on the outage critical path, and lessons focused on functional work groups from Maintenance, Engineering and Operations support teams as three of the top lessons learned during 1R25. In response to Dr. Budnitz and Dr. Peterson's observations that power ascension has multiple stages and substages Mr. Werner reported DCPP's good performance after 1R25 was due particularly to the Instrumentation and Control maintenance team, the plant's procedures, and the ownership and cross-functional efforts demonstrated by different teams working together. Dr. Peterson observed improvements in digital feedwater control over the years have been significant and Mr. Werner reported DCPP's control systems are state-of-the-art and have been improved over the life of the plant. In response to Consultant McWhorter's question Mr. Werner reported of the approximately 1,000 temporary contract workers engaged for outage 1R25 a significant number of these workers, possibly up to 80%, will return for 2R25, but final staffing is dependent on outages at other plants across the country. In response to Dr. Kadak's inquiry Mr. Werner confirmed the Westinghouse firm will be engaged for certain work and local residents and hiring halls are other sources for temporary workers.

Dr. Budnitz observed that unlike certain other industries the nuclear industry has a strong practice and a higher level of sharing of information, not only for safety but also operating and reliability experience because nuclear power plants do not commercially compete with one another. Dr. Budnitz observed and Mr. Werner agreed that DCPP's good performance on power ascension after 1R25 is likely due in part to this sharing of experience.

Mr. Werner reported the 2R25 outage goals are similar to those for 1R25 and continue to be evaluated, particularly the dose goal for 2R25. He reported that 2R25 key scope, primary, secondary, electrical scope, relicensing inspections and pressure vessel inspections will be very similar to those for 1R25, without the removal of a reactor pressure vessel surveillance capsule. In response to Dr. Kadak's question Mr. Soenen replied that as a result of license renewal inspections performed during 1R25 as part of the Aging Management Plan inspections there were no components identified as needing earlier replacement for the period of extended operation.

Following Mr. Werner's presentation in response to inquiries by Dr. Gene Nelson of the group Californians for Green Nuclear Power, Mr. Werner reported in its replacement of the high- pressure turbine rotating elements the plant does not foresee and did not pursue additional megawatt output, but there may be some efficiencies and a few megawatts produced through improvements to the steam flow path and clearances in the turbine. Mr. Werner reported his organization plans for three outages in advance and is now in the R26 stage of outage planning. Mr. Werner reported the weight of the high-pressure turbine's rotating elements is approximately 56 tons.

Mr. John Geesman, representing the group Alliance for Nuclear Responsibility was recognized. In response to Mr. Geesman's query Mr. Werner reported the upgrades to the fuel management system described in his presentation were part of the PMO[6]++ Program[7] and strategy.

Ms. Linda Seeley was recognized. In response to Ms. Seeley's query as to the nature of the high-pressure turbine replacement Mr. Werner stated that project is a reliability-based project and benefits California's energy customers. Dr. Budnitz observed the project represents a like-for-like replacement.

Ms. Lopez then introduced Mr. Soenen to make the next presentation and she reported Mr. Soenen is responsible for the license renewals of both the power plant and the Independent Spent Fuel Storage Installation (ISFSI), PG&E dry cask storage facility. She reported that Mr. Soenen has more than 24 years of experience in the nuclear industry including 20 years with PG&E in increasingly responsible roles in licensing and regulatory projects. Mr. Soenen holds a Degree in Mechanical Engineering from the University of California at San Diego.

Update on the Removal of Reactor Embrittlement Specimen Capsule B

During Refueling Outage 1R25.

Mr. Soenen stated PG&E successfully removed Unit 1 reactor pressure vessel surveillance Capsule B during the 1R25 refueling outage in April 2025. He reported DCPP's Reactor Integrity Program is in full compliance with federal safety oversight regulations and the License Renewal Application (LRA) includes the basis, using currently available information, for concluding that both reactor vessels will remain safe for 60 years, which includes the period now designated for extended operation. He reported this topic was addressed in Section 4.3 of the LRA as a part of the NRC completed independent review which concluded the plant is in compliance with all guidance documents. Dr. Peterson observed that the NRC has issued the Safety Evaluation Report (SER) for the license extension and the Committee should review the SER.

Mr. Soenen reported that for Unit 2 all reactor vessel surveillance coupons have been previously withdrawn and the data in the LRA demonstrates the acceptability of Unit 2 through 60 years of operation. He stated for Unit 1 reactor vessel coupon data provided in the LRA also demonstrate acceptability through 60 years of operation and DCPP followed the recommendation of the guidance documents regarding withdrawing one final coupon, Capsule B, which due to its placement in the reactor close to the fuel has experienced a lead factor of radiation exposure of approximately one to two times what the vessel itself would be expected to see at the end of the period of extended operation.

Mr. Soenen reported PG&E successfully retrieved surveillance Capsule B during 1R25, which has approximately 101 Effective Full Power Years (EFPY) of radiation exposure. Dr. Kadak questioned that as the Unit 2 vessel has no more surveillance capsules whether PG&E would have sufficient data for a license renewal of up to 80 years of operation, as some plants have already gone to license renewal for 80 years. Mr. Soenen stated he would need to review further to answer Dr. Kadak's questions and an answer would include the assessment of the applicability of sister plant data and he commented DCPP's focus now is to follow the state's mandate for operations going to 2030. Mr. Soenen reported that the last capsule withdrawn from Unit 2 had 52.6 EFPYs of exposure which meets the acceptance criteria for the period of extended operation. Dr. Kadak suggested for purposes of asset protection additional capsules could be placed in Unit 2 to be able to justify continued operation for that unit if a decision is made to apply for a license extension from 60 to 80 years.

Mr. Soenen stated DCPP worked with industry experts to evaluate available options to safely remove Capsule B and employed lessons learned from the previous unsuccessful attempt made including modifying the long-handled tool used to engage and remove the capsule plug from Capsule B. The long-handled tool was successfully used in 1R25 to remove Capsule B and other contingency options were not required. Mr. Soenen stated during 1R24 there were issues with the long-handled tool not being able to engage with the plug and the tool was modified to have a stronger pull force capability. He reported, in response to Dr. Peterson's questions, that the plug is not threaded nor is it press-fitted to the capsule, it is held in place by its weight. In response to Dr. Kadak's inquiry Mr. Soenen stated that during 1R24 there were contingency plans to use a side hammer to remove the plug, but all the contingency plans were based upon the tool being able to engage the top of the access plug which proved not to be the case due to unexpected deformation of the plug which did not allow the long-handled tool to latch on to the plug.

Mr. Soenen displayed and described photos and a video of the successful removal of Capsule B and he reported Capsule B, which is very radioactive, was placed in a shielded canister which was then placed within the Spent Fuel Pool, the canister was then closed and decontaminated and placed in a shipping canister and it has now been transported offsite to Pennsylvania for testing and analysis at a Westinghouse facility. Dr. Budnitz observed when in the fission process neutrons strike iron they produce radioactive isotopes of iron and of cobalt which remain radioactive for long periods. Mr. Soenen commented that after its removal, the plug is no longer needed and is placed in a waste container and stored in the Unit 1 Spent Fuel Pool. He reported NRC regulations require the results of the tests and analyses to be submitted to NRC within 18 months of the withdrawal of the capsule and the results will be publicly available once submitted to NRC. Dr. Budnitz commented and Mr. Soenen agreed that Westinghouse employs an industry standard methodology, developed by the American Society for Testing Materials (ASTM), which is used industry-wide for how the sample coupons, which consist of actual samples of reactor and weld materials, are prepared and the results measured and this testing program is regularly reviewed by outside quality assurance inspectors and by the NRC to ensure Westinghouse performs the analyses and evaluations consistent with the guidance documents.

Mr. Soenen reported that surveillance Capsule B will be moved into a Hot Cell at the Westinghouse facility and disassembled. Approximately 80 of the test samples are tested by multiple types of destructive, mechanical, and dosimetric testing methods which are performed in parallel on the irradiated capsule's contents. Based on the dosimeters in the surveillance capsule, Westinghouse completes a neutron fluence analysis. Evaluation results are documented in a Surveillance Capsule Report that is required to be submitted to the NRC within 18 months of capsule withdrawal and will then be available to the DCISC.

In response to Dr. Meshkati's observation Mr. Soenen confirmed the data will be judged as credible or non-credible. Mr. Soenen reported that if the data as not credible generic information which has higher uncertainties associated is used and he stated Committee Consultant Dr. Mark Kirk did sensitivity analyses and demonstrated that regardless of the data being credible or non-credible the criteria for extended operation for DCPP would still be met. In response to Dr. Meshkati's citation to 10 CFR[8] 50.61a and ASTME 1921 and the need for additional analysis if the data is non-credible, Mr. Soenen stated 10 CFR 50.61a is the alternative pressurized thermal shock NRC regulation and would be an option for DCPP if the projections exceed the criteria, but regardless of the data being credible or no-credible DCPP could still meet the criteria through 20 additional years of operation. He reported that if there was an unexpected projection those exceeded that criteria, in that event 10 CFR 50.61a would be a viable option and this would require additional analysis and an update to the License Renewal Application.       

            Ms. Jane Swanson of the group San Luis Obispo Mothers for Peace was recognized. In response to Ms. Swanson's question Mr. Soenen reported Capsule B was shipped offsite in a shielded transportation canister which was about eight feet tall and stored in a horizonal configuration of about four feet by four feet and it was then shipped to Pennsylvania on a semi-truck.

Ms. Jan Boudart was recognized and she stated she did not understand the distinction between credible and non-credible data and how, if it takes 18 months to get the results of the testing, can DCPP be evaluated to qualify for twenty more operational years. Dr. Kadak responded and replied that if the data is found to be credible that means it falls within the expected range of performance for metals that have been similarly irradiated and is in accordance with NRC standards in terms of expectation for embrittlement for levels of exposure to neutron flux. Non-credible means that the data falls outside of the expected range. He stated the reason DCPP can continue to operate pending receipt of the Capsule B test results is that the present data on hand which includes eleven data points, which come from Unit 1 and from the Palisades Nuclear Power Plant in Michigan which a sister plant to DCPP, confirms that the plant can operate for up to sixty years. Based on its location in the reactor vessel and the neutronic analysis of the flux at that point, the Capsule B data are expected to show operational capability far beyond sixty years and is in that sense a confirmatory sample that the current projections are valid.

            A short break followed Mr. Soenen's presentation.

Mr. Soenen then introduced Vice President of Engineering Mr. Allen Wilson. Mr. Soenen reported that Mr. Wilson has 14 years of experience with PG&E and he has served in various increasingly responsible roles in the Strategic Projects, Engineering, Maintenance, Decommissioning organizations and as Director of Engineering Projects and Outages. Prior to working for PG&E Mr. Wilson served as a reliability engineer with the United States Navy and the Coast Guard and in various civilian engineering capacities and he was responsible for creating and testing vessel maintenance and lifecycle management plans.

Overview of and Update on Engineering Department Organization, Staffing, Roles, Performance History and Improvement Initiatives, and Project Planning/Approvals.

            Mr. Wilson stated the Engineering Services organization's role is to serve as the technical conscience for the plant, meaning the Engineering Department ensures the plant maintains its license, the necessary repairs are made to keep operations within the license, and modifications are done in accord with license basis evaluations. He described and discussed the component organizations within Engineering Services for which in his role as Engineering Director he has overall responsibility:

→        Strategic Engineering – previously known as System Engineering, looks at plant systems and components and performs trending analysis. Strategic Engineering also reviews systems for obsolescence and performs complex troubleshooting.

→        Projects & Design Engineering – reviews projects and implements modifications and performs configuration management reviews to remain within the licensing basis.

→        Program Engineering – runs various plant programs including the Aging Management Programs.

→        Tactical Engineering – is part of the Fix-it-Now (FIN) organization and is responsible for immediate troubleshooting and necessary and emergent designs or modifications.

            Mr. Wilson reported that Engineering Services now consists of approximately 120-125 persons which is an increase from 80 individuals prior to the decision to consider the extension of operations, with an ultimate goal for the organization to consist of between 110-115 individuals. He stated Engineering Services is comprised of engineers who are early in their careers (20%), mid-career engineers (60%), and senior engineers who are eligible to retire in the near future (20%). He reported knowledge transfer and proficiency are focuses for Engineering Services. There is a focus group in the organization that reviews and determines necessary training to ensure knowledge transfers occurs among the engineering teams.

Dr. Peterson commented on the accelerated use and implementation of electronic procedures in the effort to improve human reliability and he reported the DCISC's present recommendation to itself is to review the implications of the use of artificial intelligence (AI) from the perspective of operational safety in furtherance of improving reliability and he commented the DCISC should continue to follow these issues. Dr. Meshkati commented that during a report on a fact finding later at this meeting an item will be presented on electronic procedures which includes discussion of the importance of proper human system integration. Mr. Wilson stated he would need to review and provide the specifics of the implementation of AI in context of the engineering organization. He reported the plant currently utilizes an older version of electronic work orders and procedures for simple maintenance tasks, but there is an effort to move toward use of electronic procedures for the Engineering, Operations and Maintenance organizations in line with those in use elsewhere in the nuclear industry. He remarked there is an immense amount of testing any time a new procedure is rolled out. Dr. Peterson noted that with electronic procedures additional things can be done related to human factors such as tracking the experience of specific individuals with performing the specific work and the frequency that they have performed those tasks in the past and this allows adjusting and including additional procedural measures accordingly to their experience and he observed these benefits can be seen to fit within the ambit of knowledge transfer.

Mr. Wilson reported the principal way employee proficiency is managed is by engagement, including pre-job briefings, developing standards on procedural use and adherence, peer-to-peer coaching, training and qualifications, and by having management conduct observations and mentoring in the field. He reported that all new engineers regardless of experience go through an initial systems training regime to learn how the plant systems interact and he reported every engineering job at the plant requires some type of qualification and work-group specific training is required for the entire engineering team. Mr. Wilson reported the principal focus for Engineering Services has been on the effective management of the increased staffing through leadership engagement and observations.

Mr. Wilson reported the best and greatest impact on equipment reliability is achieved through projects and the plant continues to make the necessary investments in projects to ensure safe and reliable operations. He reported the NRC continues to inspect and affirm the safety of operations as does the DCISC. He remarked that for identified projects the process consists of three phases which include design, procurement, and material fabrication. He identified in this context the Unit 2 high-pressure turbine installation during 2R25 and the contingent replacement of the feedwater heaters, which for the feedwater heater project he reported is in the design and the beginning fabrication phase. Mr. Wilson provided a list that summarized projects for Unit 1 and Unit 2 and he observed a number of projects are planned on secondary side systems. Primary side projects are planned to deal with obsolescent items including the digital rod position indicator and the paper chart recorder. He reported projects for 2R25 are similar to those performed for 1R25 with the steam generator blowdown tank replacement being a project for Unit 2 that was not done during 1R25. Common unit projects include the biological lab system upgrades and the plant's air compressors along with refurbishing and relocating the spare high-voltage transformers.

In response to Consultant McWhorter's inquiry Mr. Wilson stated with reference to the feedwater heater replacement project that the feedwater heaters life-cycle windows are being reviewed to determine the need for their replacement and that replacing the individual feedwater heaters is contingent on that review and he commented there is a long lead time as fabrication of a feedwater heater can take up to three years to complete and all the feedwater heaters required will not be completed before the end of 2026 or the beginning of 2027. He observed there are issues involved with interference caused by removal of the feedwater heaters, of which there are 12 per unit, 24 in total, and the health of the feedwater heaters will be assessed and a decision made from the perspective of their replacement in view of the 2030 operational timeline. In response to Dr. Meshkati's question Mr. Wilson reported the Main Annunciator System for Unit 2 will be replaced during a future outage in 2026.

Dr. Gene Nelson of Californians for Green Nuclear Power was recognized. In response to Dr. Nelson question concerning a project involving the 10% steam dump controls and Dr. Nelson's observation that a Westinghouse four-loop pressurized water reactor with appropriate steam dump can be allowed to operate down to 15% of its rated power output or in idling mode, Mr. Wilson replied DCPP is not making any modifications in order to do any kind of idling or load following operations. The modification referred to by Dr. Nelson represented a deferred corrective action which will enable down power operation in order to be able to maintain the plant in hot standby condition separately from the capacity afforded by its 40% steam dump capability and the project was part of the PMO++ review process. In response to Dr. Budnitz' observation Mr. Wilson confirmed DCPP can continue to operate safely at any power level.

The Chair requested Mr. Rathie to make the next presentation. Mr. Rathie stated he would be assisted in this presentation by his colleague Mr. Willis Hon, a partner in the Nossaman LLP law firm who serves as special counsel to the Committee.

Status of Governmental Agency Interactions, Response to the California Public Utilities Commission Pending Decision in R.23-01-0-07, Decision on Phase 2 Issues including Future Funding for Committee Activities and other Financial Matters, Regulatory and Administrative Matters including review of a Proposed Fourth Restatement of the Committee's Charter; Consideration of Revised and New Committee Policies and Other Committee Discussion.

Mr. Rathie reported that on behalf of the Committee communications have been exchanged with the CPUC's Independent Peer Review Panel (IPRP) for seismic studies of the site and its environs of Diablo Canyon, principally in context of the engagement and the work of the DCISC Seismic Review Team (SRT). There were also contacts exchanged with the California Energy Commission on this topic and a draft Committee policy on responding to emergencies at DCPP which will be discussed later at this meeting. Mr. Rathie reported he and Mr. Hon have also had contacts on several occasions with the CPUC Energy Division.

Mr. Rathie reported with Mr. Hon he had hoped that the CPUC's decision in Phase 2 of rulemaking proceeding R.23-01-007 would have been final, however, that decision will now be considered at a voting meeting of the CPUC to be held on June 12, 2025. He commented that a Proposed Decision has been issued for review in that matter and at this time no changes relevant to issues affecting the DCISC are expected when the Commissioners consider the matter. Mr. Hon then continued the presentation.

Mr. Hon reported that a copy of the Proposed Decision was included in the public agenda packet for this meeting and while the majority of that document deals with issues relevant to PG&E's obligations related to volumetric performance fees, the Proposed Decision would also adopt the methodology for the Committee's budget during the period of extended operation of DCPP. That proposal would adopt the greater of the current funding level approved in past decisions or the average of DCISC expenditures for 2023-2024-2025 and increase that later amount by the increase in the California Consumer Price Index or 3% whichever is greater. Any unspent funds at the conclusion of the calendar year would be returned to PG&E for credit to the load-serving entities providing the funding. Invoices for funding would continue to be submitted by the Committee to PG&E.

Mr. Hon also reported the Proposed Decision addresses proposals made by the Alliance for Nuclear Responsibility and the Small Business Utility Alliance which would impose term limits for membership on the DCISC. He reported that the Proposed Decision denies the proposal for term limits. The Proposed Decision would also close R.23-01-007, but Counsel for the Committee will continue to follow and monitor other CPUC proceedings which affect DCPP. He commented the Proposed Decision has been held several times by the Commissioners due to the issues around the volumetric performance fees, but he believes the Commissioners will now take up the Proposed Decision on June 12, 2025.

Mr. Hon reported that when the Proposed Decision is final, it will direct PG&E to file a Tier 2 Advice Letter within 90 days of the effective date of the Decision which requires approval by the CPUC Energy Division to adopt a Fourth Restatement of the Committee's Charter consistent with the Decision and statutory updates. Mr. Hon reported a draft Fourth Restatement has been prepared by Counsel and is included in the public agenda packet and at this time it would be appropriate for the Committee members to consider giving the draft Fourth Restatement their conditional approval, with the only condition being that the CPUC Commissioners adopt the Phase 2 Decision without any material changes from the current version.

After discussion on the effect of the condition described by Mr. Hon, on a motion made by Dr. Peterson, seconded by Dr. Meshkati, the Committee members unanimously approved the draft of the Fourth Restated Charter for the Diablo Canyon Independent Safety Committee.

Ms. Rochelle Becker of the Alliance for Nuclear Responsibility was recognized. Ms. Becker stated the objective of the Alliance in seeking term limits for DCISC membership was to be consistent with the CPUC, the NRC, and certain elected officials. Ms. Becker remarked she did not believe it was healthy from the viewpoint of safety not to have term limits and doing so would ensure independence.

Dr. Gene Nelson of Californians for Green Nuclear Power was recognized. Dr. Nelson commented the DCISC is unique in that it requires deep technical understanding and that is why Californians for Green Nuclear Power opposed the proposals for membership term limits.

Mr. Rathie reported another item on the CPUC agenda concerns the Commissioners' ratification of the CPUC President's selection of candidates for the Attorney General's appointment of a member of the DCISC. He reported the three candidates are Dr. Budnitz, for reappointment, and Dr. Raluca Scarlat and Dr. Michael Quinn for appointment.

Mr. Rathie next reported on the Committees' present financial condition and remarked that the Committee is solvent and continues to be able to pay its bills on a "cash and carry" basis. He reported three quarterly payments of grant funds provided by PG&E ratepayers under PG&E's General Rate Case have been received and the Committee, during the period of transition and relicensing for extended operation, also receives funds from the Diablo Canyon Transition and Relicensing Memorandum Account (DCTRMA) as authorized by the CPUC Decision in Phase 1 Track 1 of R.23-01-007. He reported that the Commission recognized that the Legislature, by its adoption of Senate Bill 846,[9] would cause an increased workload for the Committee in its review of topics related to relicensing and extended operation. He reported 2025 will be the final year DCTRMA will be available to the Committee and in 2026 and in future years the funding for Committee activities will come from the load-serving entities benefitted by the electricity produced by DCPP extended operation.

Mr. Rathie asked for the Members and Consultants' comments on the development of a process map addressing the recommendations made and concerns raised by the Committee in its review of DPP operational safety. A draft of a process map was included in the agenda packet. He reported at the February 2025 public meeting the Committee discussed and adopted a format for making internal recommendations, i.e., recommendation to the Committee by the Committee, and for recommendations by the Committee to PG&E which when made in the Committee's Annual Reports require a written response from PG&E. Mr. Rathie stated the process for addressing recommendations and concerns will affect and complicate development of the Open Items List which is a very useful tool used by the Committee in its reviews. Dr. Peterson observed it is important for the Committee to have a specific process to address and track its recommendations and concerns and to close them when appropriate. He commented that although the Committee has no regulatory authority, PG&E has been responsive to the Committee's recommendations. He remarked that a concern represents a recognized question or issue which is shared by the DCISC and by PG&E.

Dr. Meshkati remarked that in his experience there are findings associated with recommendations and a single finding could result in several recommendations and he commented there can be another level, termed observations which are matters that are not necessarily related to a major issue, but which the reviewing body wishes to have as a statement in its records for possible future action. Dr. Meshkati stated his belief that the beginning of the use of artificial intelligence applications (AI) by DCPP is an issue warranting an observation by the DCISC to document the Committee's intent to follow up on this topic and he requested the term "observation" be added to the draft process map.

Mr. Rathie observed in the past the Committee's concerns have generally emerged in context of the Committee's approval of its Annual Reports and he viewed the process map under discussion as a possible appendix to Committee Policy No. 8 concerning procedures for the approval of its fact finding reports. He remarked that in his opinion adding continuing concerns along with observations from the fact finding reports increases the level of detail in the Open Item List and makes that document more complex, whereas in the past the Open Items List has been a relatively simple tool which is presently tied only to Committee recommendations. Consultant Wardell stated the Open Items List has gotten more complex and a considerable amount of effort goes into updating and reviewing the Open Items List, but he remarked it was his belief the Committee needs such a vehicle to record and track its recommendations, concerns, and observations and to summarize them in the executive summaries of the Committee's Annual Reports.

Mr. Wardell stated it is his belief that concerns and recommendations should be added to the Open Items List. Consultant McWhorter expressed his view that the question of whether there is an expectation for future action associated with an observation or a concern is an important factor. Dr. Peterson observed perhaps concerns should be treated as any other item on the Open Items List to be tracked and to be closed the same as other items. Mr. Rathie remarked concerning AI that there is now an item on the Open Items List and if that item is to be characterized as an observation that designation should be made by the fact finding team. Dr. Meshkati commented hierarchy in this context is important and in his opinion an observation is not as important as something that should be scheduled for a fact finding meeting and he again mentioned AI as an issue which, although in its embryonic state, needs to be kept "on the Committee's radar screen" as decisions are made and actions are taken concerning an item identified as an observation. Dr. Kadak remarked that he would differentiate concerns and observations on the basis of items that are and are not at that point in time actionable. Dr. Budnitz observed there are perhaps a hundred items on the Open Items List and some are reviewed or monitored annually or more frequently and others less frequently and this frequency is based upon the Committee's judgment and he stated he sees these items as concerning things that do not rise to concerns. He commented if an item is found not to be satisfactory PG&E may be aware of the issue and be taking immediate and, in the Committee's view correct action to address the issue, and he observed this is what the Committee is referring to as a concern and in those instances the Committee's obligation is to ensure PG&E continues and completes the action. In cases where the DCISC observes an issue of which PG&E is unaware, or for which its programmatic approach is not good in the DCISC's view, in these cases a recommendation is warranted. Dr Budnitz remarked, however, that he does not see a need for or the utility of a document to explain the differences. Dr. Peterson remarked that a document that provides a formal process for identifying items in these defined categories and also provides a vehicle for managing and formally closing recommendations and concerns will be useful.

Dr. Peterson delegated to Counsel and the Committee's Technical Consultants the task of updating the draft process map in a reasonable manner based on this discussion and remarked that subsequently the Committee Members can return to manage and update the process map as needed. Drs. Meshkati and Peterson remarked the principal key to an update lies in articulating the definitions of a concern and an observation. At this point, the Committee tabled the discussion of this item. 

V         ADJOURN MORNING MEETING            

            The Chair adjourned the morning meeting of the DCISC at 12:08 p.m.

VI        RECONVENE FOR AFTERNOON MEETING

            The afternoon meeting of the DCISC was convened by the Chair at 1:15 p.m.

VII      COMMITTEE MEMBER COMMENTS

            There were no comments by any member at this time.                      

VIII     PUBLIC COMMENTS AND COMMUNICATIONS

            Dr. Peterson invited members of the public to address the Committee on matters not on the agenda for this meeting. There was no response to his invitation.

IX        DISCUSSION, DIRETION AND ACTIONS, AS APPROPRIATE, BY THE COMMITTEE, CONSULTANTS AND COUNSEL

Committee Discussion of Recent Presidential Executive Orders Regarding Regulation and Licensing of U.S. Commercial Nuclear Power Facilities and Committee Path Forward for Monitoring and Future Inquiry into the Effect on DCPP.              

            Dr. Peterson stated he believed the Committee Members have all reviewed the recently issued Presidential Executive Orders affecting the NRC and they represent matters which the Committee will need to follow as they are likely to have some impact on NRC regulations. Dr. Budnitz stated he is presently assisting the NRC with the development of regulations for new advanced reactors, a task unrelated to DCPP, and he commented he has a concern as he understands a principal intent of the Executive Orders is to require the NRC to realign its resources and this could cause a decrease in the NRC's effectiveness and ability in the long term to regulate operating plants such as DCPP. He observed the NRC staff's ability to review the technical submissions from operating plants is excellent today, but he remarked that NRC staff use knowledge, measurement and analysis methods which are developed by the NRC Office of Research and when regulations need to be changed the Office of Research develops a technically sound basis for the regulations. Dr. Budnitz stated he fears there may be a plan to abolish the Office of Research, where he once served as the Director, akin to what has happened recently at other federal agencies. He commented that watching to ensure there is no reduction in the capabilities of the NRC staff and for a negative impact in a number of other areas will be important.  

Dr. Meshkati stated he has been studying the Executive Orders and reported there is some good analysis available including by the American Nuclear Society, the Nuclear Innovation Alliance and by Dr. Edwin Lyman of the Union of Concerned Scientists which he commended to his colleagues' attention. Dr. Meshkati stated he was concerned about the NRC losing its independence and he remarked it is his belief that no matter what happens with the NRC, the onus for nuclear plant safety lies with the operator and the owner. Mr. Meshkati stated he believes the issuance of the Executive Orders and the reforms at the NRC make the DCISC more relevant. He observed that to his knowledge there is no other independent nuclear safety committee similar to the DCISC. He remarked over the past forty years since the accident at Three Mile Island Nuclear Generating Station in Pennsylvania in 1979, then later at the Chernobyl Nuclear Power Plant in the Soviet Union in 1986 and still later at the Fukushima Dai-ichi Nuclear Power Plant in Japan in 2011, there have followed what he termed nuclear renaissances and he observed it has been said a nuclear accident anywhere is a nuclear accident everywhere. He stated another aspect of the Executive Orders may be to assist in restarting nuclear power plants and repurposing them. He commented Dr. Lyman has projected a need for an increase of 400 gigawatts by 2050 which is the equivalent of 300 nuclear power plants and with the NRC staff budget decreasing, Dr. Meshkati stated he sees a widening gap and the only way to ensure nuclear safety may be for utility owners and plant operators to be more cognizant of committees similar to the DCISC. He observed the Executive Orders proposing reformation of the NRC Advisory Committee on Reactor Safeguards (ACRS) may result in getting fresh disciplines into that Committee as in Dr. Meshkati's long-held opinion the composition of the ACRS could benefit from a change.

Dr. Peterson stated there will be potentially substantial effects from the Executive Orders and it is difficult to predict what those may be. He remarked the NRC's independent status from politics as a safety regulator was a correct decision made in the Eisenhower administration in context of the Atomic Energy Commission when the U.S. Department of Energy (DOE) was given an advocacy role as well as responsibility for defense-related facilities. Dr. Peterson stated in his opinion that the NRC has done a better job of regulating than the DOE. Dr. Peterson commented the NRC's independence from politics has been one of the reasons the NRC can assess issues at nuclear power plants as having low levels of safety significance. He commented that an important part of safety culture is creating an environment where reporting of problems at a low level is encouraged. In reply to Dr. Peterson's query Mr. Soenen reported DCPP generates thousands of Notifications[10] each year. Dr. Peterson remarked when corrective actions are not effective that is when a concern should be triggered and the independence of the NRC is a necessary component to protect and support safety culture from political influence.

Dr. Kadak observed one of the lessons after the accident at the Three Mile Island Nuclear Generating Station in Pennsylvania was that the ultimate safety of a plant is a function of the plant and the people who run the plant and no regulation can assure safety. He commented PG&E will continue to run DCPP as best they know how and as safely as they know how because it is not in their interest to do anything else.

Dr. Peterson directed that an item be added to the Open Items List, in broad terms, to follow up on the Executive Orders at a future fact finding and plan to review the topic at the October 2025 public meeting. Consultant McWhorter commented all Presidential Executive Orders require written responses to further define the path forward and the DCISC item should include review of the NRC's responses. Dr. Budnitz remarked there are many groups in the nuclear industry that will be reviewing and expressing opinions on this topic. Dr. Meshkati raised the possibility of inviting a knowledgeable speaker or speakers to educate the Committee on this topic at the October 2025 public meeting.

Dr. Gene Nelson of Californians for Green Nuclear Power was recognized. Dr. Nelson stated he does not believe the NRC can operate free from political influence and gave as an example a former NRC Commissioner who, following his tenure on the NRC, admitted to being an opponent of nuclear power. Dr. Nelson remarked that in his view in order for the NRC to be successful there must be persons on the Commission that support nuclear power. He also stated he supports the decision of the CPUC to create the DCISC and commented it is an excellent idea which should be replicated widely.

Mr. John Geeman of the Alliance for Nuclear Responsibility was recognized. Mr. Geesman remarked the Executive Order in the public agenda packet for this meeting was the most general of the orders issued. He observed that this Order proposes changes which lack a scientific basis and accordingly they produce an irrational result. These include the provision that addresses the safety models currently used by the NRC for threshold radiation exposure with harm proportional to the amount of exposure. Dr. Geesman suggested an inquiry into this area might benefit from review of the center, body and range of informed scientific technical opinion. He observed the direction to adopt and consider reliance on a linear no-threshold model of radiation exposure in the As Low As Reasonably Achievable (ALARA) standards requires reliance on flawed models and he remarked he believes this represents a major threat to the continued operation of nuclear power plants not only in the U.S. but around the world. Mr. Geesman commented he doubts the Department of Government Efficiency (DOGE) is likely to add much to the technical understanding of this issue and as there have been changes at DOGE since the Executive Orders were issued, DOGE's contributions may be more negative than otherwise. He remarked that the Executive Order proposal to reduce the ACRS to the minimum necessary to fulfill statutory obligations represents more than just seeking turnover on that committee.

Review of Future Meeting Dates; Documents Provided to the Committee; Correspondence Exchanged Including Concerning Recent Media Inquiries, and Unit 1 Reactor Pressure Vessel Integrity.

B.        The Members and Consultants discussed and confirmed future public meetings of the DCISC for October 22-23, 2025, February 18-19, 2026, and June 16-17, 2026, and the Members and Consultants then scheduled a public meeting for October 20-21, 2026. The Committee Members discussed opportunities to schedule a plant tour with members of the public, possibly at the February 2026 public meeting. Dr. Budnitz explained the importance to the Committee's public tour program of the ability to visit the Control Room Simulator Facility with members of the public and the importance of the Simulator to the scenarios conducted for the evaluated emergency exercises which utilize the Simulator and other emergency response facilities. He remarked that the Committee understands that with the relicensing activities in furtherance of extended operation and for other training purposes DCPP has a need to make frequent use of the Simulator.

            Fact-finding visits were then confirmed, subject to confirmation by DCPP that the plant can support visits on the selected dates, and scheduled as follows[11]:                             

[2025] July 21-22 (PFP/RFW) [changed from July 29-30]; August 19-20 (NM/RFW) [changed from August 12-13], September 16-17 (RJB/RDM), November 18-19 (RJB/RFW); December 15-16 (PFP/RDM); and for

[2026] January 20-21 (NM/RFW), March 10-11 (RJB/RDM), April 22-23 (NM/RFW), May 6-7 (PFP/RDM), July 14-15 (PFP/RFW), August 11-12 (NM/RDM), and September 15-16 (RJB/RFW).

The Members requested Ms. Lopez to review the new dates proposed to ensure the plant can accommodate the Committee on those days. Mr. Soenen commented he would provide the dates for the next evaluated emergency exercise and for the NSOC exit meeting.

Mr. Rathie reported that a recent inquiry from a member of the news media brought to the Committee's attention a report by the NRC Office of the Inspector General which regarded an allegation of collusion regarding information concerning seismic safety between PG&E and the NRC during the period 2013-2014 which arose in context of the NRC Differing Professional Opinion Program (DPO)[12]. Dr. Meshkati observed the substance of the allegation had been the subject of a Congressional hearing and litigation and he questioned what further contribution a substantive DCISC inquiry into the matter might serve and accordingly, he remarked the matter before the Committee now was in context of whether, and if so to what extent, the Committee should in the future review matters brought to its attention and raised under the NRC DPO Program. Dr. Budnitz commented that PG&E also has DPO Program for DCPP and there is an item on the Open Items List now (HS-6) which documents the Committee's reviews of that program. Consultant McWhorter reported there have been occasions in the past when the Committee has reviewed reports from the NRC Office of the Inspector General, most recently concerning the Auxiliary Feedwater System and earlier concerning an issue regarding the supply of fraudulent parts to nuclear plants. Consultant McWhorter suggested and the Members agreed to adding a new item to the Open Items List under the Nuclear Safety Review and Oversight category to review as needed any Office of the Inspector General reports or NRC differing professional opinions brought to the Committee's attention which involve DCPP.

Mr. Rathie reported that since the last Committee public meeting in February, additional correspondence was received from Mr. Bruce Severance, who has on several other occasions exchanged correspondence with the Committee and made public comments at its meetings with reference to Mr. Severance's continuing concern regarding the integrity of the Unit 1 reactor pressure vessel. Mr. Severance submitted as part of his latest communications a list of six questions to which Consultants Dr. Mark Kirk and Dr. Andrew Kadak provided responses which were sent to Mr. Severance and posted to the Committee's website before this meeting. Mr. Rathie reported that none of the questions Mr. Severance posed influenced or altered the conclusions made regarding the state of embrittlement of the Unit 1 reactor pressure vessel documented in the two reports by Dr. Kirk presented to and endorsed by the Committee in 2024 and which were included in their entirety in the Committee's 34^th Annual Report.

Dr. Meshkati stated that he has, separately and apart from Mr. Severance's questions, submitted eleven queries to Drs. Kirk and Kadak to which he has now received responses and he has had a follow-up meeting with Drs. Kirk and Kadak. Dr. Meshkati stated he has made additional requests for information as he continues to have questions regarding the uncertainty characterization in context of embrittlement. Accordingly, Dr. Meshkati stated he was not in a position to consider endorsing Drs. Kirk and Kadak's replies to Mr. Severance's six questions due to the overlapping issue of uncertainty.

Dr. Kadak stated that regarding the uncertainties, in simple terms uncertainties are combined and integrated into the NRC rule and into the acceptance standards for the assessment of the reactor surveillance specimens undergoing the Charpy V notch test[13]. If the Charpy tests show non-credible performance then uncertainty requirements provide for added conservatisms. He stated this is an industry accepted technique to deal with uncertainties in the massive amounts of data that has been collected by the industry. Dr. Kadak stated Dr. Meshkati had questioned how the results of testing of Capsule B will not affect the acceptability under the regulations of Unit 1 for five more years of operation. Dr. Kadak stated whether the Capsule B data is credible or non-credible, the test results that PG&E now has demonstrate that the Unit 1 reactor pressure vessel is capable of operating safely for fifty years. He reported parametric studies[14] were done for both credible and non-credible which demonstrate Unit 1 is acceptable for fifty years of operation which provides confidence to conclude it is acceptable for five additional years of operation. He stated the uncertainties are addressed by the regulatory process which provides for adding additional conservatisms.

Dr. Peterson observed the regulations have a systematic methodology to estimate and quantify uncertainty and use of that methodology leads to the conclusions Dr. Kirk and Dr. Kadak have reached. He remarked there is a question of what results might be reached if one used an alternative methodology to that in the regulations. Dr. Peterson remarked embrittlement is only one part of a larger set of sequential events that would have to occur for embrittlement of a vessel to result in core damage and he observed conservatisms embedded in other parts of the analyses of pressurized thermal shock[15] (PTS), which include actions by the plant staff can reduce substantially the probability of the transients[16] occurring. Dr. Peterson stated that he accepts the use of the existing methods for assessing uncertainty, coupled with the other parts of an analysis of a PTS accident and he commented he is comfortable that this is not a substantial source of risk for the operation of the plant. Dr. Meshkati stated he agrees with Dr. Peterson's assessment as to the level of risk to the plant's operation, but he observed one cannot say with a high level of certainty that the conclusion is now "cast in iron" and his questions are specifically about the uncertainty characterization based on available methodology. He remarked there is a difference between complying with regulations and seeking a higher level of safety and regulations generally serve as a floor for safety as a minimum common denominator and therefore complying with regulations does not necessarily mean achieving safety and he commented that achieving safety should be the goal of the DCISC.

Dr. Kadak stated he did not accept that in the regulations in the area of reactor pressure vessel embrittlement represent a regulatory "floor," rather he stated his belief that the floor has been raised by the layering of margin atop margin and uncertainties atop uncertainties to establish a level of safety. Dr. Kadak reported that with Dr. Kirk, a supplementary analysis was done using a worldwide database as well as data from the Palisades Nuclear Power Plant in Michigan, which is considered for purposes of these studies to be a "sister plant" to DCPP, and he reported this independent analysis, i.e., independent of NRC regulations, shows the DCPP Unit 1 reactor pressure vessel meets the requirements concerning its degree of embrittlement. Dr. Kadak remarked he was unsure whether there was a methodology in place now to answer Dr. Meshkati's question about the extent of the degree of uncertainty used in the NRC hazard curves.

Dr. Budnitz observed after the NRC determined the pressurized thermal shock (PTS) phenomenon was more likely than had been previously thought, a research project was initiated by the NRC while Dr. Budnitz was serving as the NRC Director of Research and also by the Electric Power Research Institute (EPRI) and the result was the regulation codified as 10 Code of Federal Regulations (CFR) 50.61 known as the PTS regulation and at that time 10 CFR 50.61 was understood to be highly conservative. He reported research then continued for a period of some ten years and the result was an alternate regulation, 10 CFR 50.61a which he described as a more realistic regulation which still has a great deal of margin. So, if a plant meets either regulation in Dr. Budnitz' view there is a great deal of margin and therefore he stated he rejects characterizing 10 CFR 50.61 or 10 CFR 50.61a as a regulatory floor. Dr. Peterson observed the Committee has always taken an independent view as to safety and while he believes there is a very strong case that the Unit 1 reactor pressure vessel is in compliance with regulations, he observed the Committee should continue to investigate, while recognizing a consensus that the analyses show that the Unit 1 reactor pressure vessel is in compliance with embrittlement regulations including regulation methodology for quantifying uncertainty. Dr. Peterson stated his recommendation was contingent upon the individual DCISC members identifying additional issues to investigate to allow the Committee to potentially understand better alternate approaches to quantifying uncertainty.

Mr. Rathie remarked that the responses to the six questions posed by Mr. Severance conclude that none of the questions influenced any of the conclusions made in Dr. Kirk's 2024 Report concerning the embrittlement status of Unit 1 which concluded the Unit 1 reactor pressure vessel met all NRC regulations and is currently acceptable for twenty years of operation beyond the original license term for DCPP. Mr. Rathie observed, in response to Dr. Peterson's query, that there is no requirement that the Committee take action on the report responding to Mr. Severance's six questions and in that event those responses remain the statements of Drs. Kirk and Kadak. Dr. Peterson directed that this issue remain on the Open Items List for continued investigation as further designated by the Members and he commented, in response to Consultant McWhorter's observation, that the next substantive information which will be made available will be the results of the testing of Capsule B. Dr. Peterson expressed the gratitude of the Committee to Dr. Kirk and Dr. Kadak for their work on this matter. Dr. Budnitz and Dr. Peterson with Dr. Kadak and Consultant McWhorter then described the reasons, rationale, conservatisms and mechanisms that could be involved in a potential PTS event. Dr. Meshkati expressed his thanks to Mr. Severance for providing background information and also some older documentation and Dr. Meshkati stated Mr. Severance has done due diligence on this issue and whether he is right or wrong is a separate issue.

A break followed.

X         CONSULTANT REPORTs & RECEIVE, APPROVE, AND AUTHORIZE TRANSMITTAL OF FACT FINDING REPORTS TO PG&E          

            The Chair requested Consultant Mr. McWhorter to provide a summary report on the March 19-20, 2025, fact-finding visit with Dr. Peterson. Mr. McWhorter reviewed the topics discussed with PG&E during the March 2025 visit as follows:

→        Spent Fuel Pool Systems with Plant Tour – Consultant McWhorter reported each unit has its own Spent Fuel Pool and Spent Fuel Pool Cooling System which consists of two pumps and one heat exchanger. He reported that in general both Unit 1 and Unit 2 systems were found in good health with no major issues. Unit 1 experienced an air seal leak in a seal air supply line to the transfer canal gate. The Fact Finding Team (FFT) reviewed the protocol to check for spent fuel pool leaks which is followed by checking leak-off lines that are located in channels under the pools and are checked monthly with no issues found to date. The FFT discussed the Fuel Transfer Systems which use mostly original plant equipment in a mechanical system to move new fuel in and old fuel out from Containment. The Fuel Transfer Systems consist of the manipulator crane in each Containment and the transfer cart and associated facilities between the Containments and the Spent Fuel Pools and the bridge crane over the pools. The Fuel Transfer System was found to be generally in good health with some upgrades in progress. Phase 1 of these upgrades was completed for Unit 1 during 1R25 and Phase 2 will complete during 1R26 with a similar schedule planned for Unit 2. The FFT also toured the plant and Mr. McWhorter displayed two photos and stated the FFT concluded the Spent Fuel Pool Cooling Systems were in good health with no major issues.

→        Configuration Management Programs – Consultant McWhorter reported the purpose of the Configuration Management Program is to ensure the design basis and documentation for all systems and components in the plant are correctly maintained. He reported change management for physical changes comprise major, minor, and non-design modifications and the classification depends upon the complexity and how the system or component is addressed in the licensing basis. Mr. McWhorter reported there has been a significant increase in design changes since the passage of SB 846 as the plant was required to augment the Program as its processes had been winding down when the plant was expected to enter decommissioning in 2024-2025. Staffing has increased and accordingly additional training has been implemented. He observed this is one of several areas where AI tools may be productive as much of the Program focus is related to research and document searches. Dr. Budnitz remarked changes may be made for several reasons including due to the design basis having been erroneously executed, due to a change in codes, or for some other reason. Mr. McWhorter stated that a significant effort known as the Licensing Basis Verification Project was made prior to PG&E entering into the Joint Proposal[17] and the Licensing Basis Verification Project was initiated to review the design licensing basis. Dr. Peterson remarked AI could possibly be employed to search through Notifications to find past occurrences when the Corrective Action Program was relevant to or impacted design changes. Dr. Meshkati stated that in context of Process Safety Management (PSM), the management of change has been mandated as part of the PSM standards to look at organizational factors and he remarked AI could be useful to look at the "ripple effect" of management of those changes which are mandated by regulation. Dr. Budnitz stated he would endorse the use of AI tools as discussed provided AI was used as a supplement and not as a replacement for what humans currently do. Dr. Peterson remarked there is an opportunity cost of making change difficult which could impact safety and facilitating change is the only way to increase the rate of improvement.

→        Station Update – Consultant McWhorter reported the FFTs for the March, April and May fact findings each received station updates similar to that provided by Mr. Rogers earlier at this meeting. He commented when the Open Items List is discussed later at this meeting he will solicit input as to the usefulness of this trial. He observed that certain information of lesser importance including the results of the Force-on-Force Drill and two human performance events of a minor nature have occurred during the time periodic station updates were provided between the Committee's public meetings. The FFT concluded the updates were informative and no new major issues were identified.

→        Meet with NRC Senior Resident Inspector – the FFT met with Senior Resident Inspector Mr. Mahdi Hayes and discussed issues of human performance and the issuance of the NRC annual assessment letter. Mr. McWhorter reported that Mr. Hayes will make a presentation to the Committee tomorrow to present and discuss the NRC's End-of-Cycle Performance Report. The FFT concluded that the meetings with the NRC inspectors continue to be beneficial.

→        Safety-Security Interface – Consultant McWhorter stated there is a formal program to manage changes to safety that might affect security and vis-a-versa. The core of this program includes regular participation by the Security and Operations organizations and the Operations organization involvement in Security activities such as the installation of barriers. He reported procedures for Emergency Plan changes must be reviewed to see how the changes affect Security and most of the significant plant changes must be reviewed by both departments. He gave the example of maintaining a particular Security fire watch inspection round during the lock-down period for the Force-on-Force Drill. Dr. Budnitz observed it is important that plant staff do not feel imposed upon by security requirements, but he commented the DCISC has seen no signs of that at DCPP.

→        Workplace Seismic Safety – Mr. McWhorter reported this review was in follow up to an issue identified in December 2024 concerning discovery of an unbraced cabinet after DCPP had conducted an extensive programmatic review to eliminate these issues. The FFT received an update on the corrective actions in progress and Mr. McWhorter stated he would further review the issue in his report on the May 2025 fact finding visit.

→        Meet with DCPP Officer – the FFT met with PG&E Vice President for Business and Technical Services Ms. Maureen Zawalick. The FFT believes these meetings continue to be beneficial for both parties. Mr. McWhorter reported that Dr. Meshkati is scheduled to meet with representatives of the PG&E Corporate Safety and Nuclear Oversight Committee.

→        New Fuel Procurement – Mr. McWhorter reported the Committee has been following this topic as part of its review of extended operations. Representatives of the DWR participated remotely in this topic. He stated when SB 846 was adopted by the California Legislature the procurement of new fuel was one of the most important and time sensitive initiatives that needed to be undertaken, as new fuel typically takes about a three-year lead time to procure. He reported that through shortening the time needed for certain activities DCPP was able to receive fuel for the next rounds of refueling outages. Mr. McWhorter reported all the fuel needed for operational cycles 25 and 26, that is for refueling outages 1R25, 2R25, 1R26 and 2R26, has been procured and is in the process of being fabricated and a supply of uranium has been procured from U.S., Canadian, and European suppliers to support operations to 2030. Mr. McWhorter reported the fuel for these outages has some minor design improvements incorporated into the fuel assemblies including changing the nozzle design at the bottom of the assembly to keep foreign material from becoming lodged between the rods where it can cause fuel failure. He reported there have been changes made to the fuel pellets to allow for higher burn-up by "doping" the pellets with small amounts of chromia and alumina. In response to FFT inquiries as to any plans by DCPP to move from an18-month to a 24-month operational cycle the reply was it is not viable to pursue that change given the five-year period provided for extended operation. In order to move to a 24-month fuel cycle enrichment would need to be increased to be greater than 5% which is the current license limit and the licensing basis and accident analyses would need to be redone. In response to Dr. Kadak's query Mr. McWhorter replied fuel performance at DCPP has been excellent with one unit having operated for thirty years without experiencing fuel failure and the other unit having operated for ten years without fuel failure. The FFT concluded procurement and processing of new fuel is being well managed.

→        Innovation Initiatives – Consultant McWhorter stated the primary focus of this topic was to clarify some terms about the use of AI. He reported Neutron Enterprise is the name of the software platform developed by the Atomic Canyon firm. The DCISC previously understood and made the statement that use of Neutron Enterprise does not generate new information, but the Committee has since learned this statement was inaccurate. Neutron Enterprise does generate new information from an existing, defined, information database that is bounded and defined in such a manner that the database takes existing information and sorts, summarizes, and creates summaries of the information. In short, Mr. McWhorter reported the employment of Neutron Enterprise and use of AI in that application at DCPP cannot generate information that does not already exist in the database. Mr. McWhorter reported implementation of the AI software at DCPP is planned for this month and trial usage was in progress during the period of the March fact-finding visit. He explained consideration is being given to future uses of AI as might be advantageous during the time period until 2030 and he reported there is the continuing and evolving NRC guidance and restrictions on use of AI to be considered. The FFT concluded that the use of Neutron Enterprise AI intelligence platform at DCPP for document search and retrieval and reporting is positive and does not pose any safety concerns. The FFT recommended DCISC should continue to review the use of AI at DCPP and to maintain a list of potential future AI applications with a potential to enhance safety. 

→        Refueling Outage 1R25 Update and Safety Plan – Mr. McWhorter reported Mr. Werner gave a presentation on 1R25 previously during this public meeting. He reported that the FFT reviewed the Outage Safety Plan for 1R25, a deterministic plan which uses risk-informed information to define the different plant configurations during the outage and provides an indication of the level of defense-in-depth for maintaining safety functions. Color-coded windows in Green, Yellow, Orange and Red are used and for a typical outage there might be a reduced number of Yellow windows where defense-in-depth is reduced to N+1. He reported there were three Yellow windows during 1R25. The FFT found the outage preparations to be proceeding well including the plans for removing Unit 1 reactor pressure vessel surveillance Capsule B.

→        Observe NSOC Exit Meeting – Consultant McWhorter reported the FFT attended in person a meeting of the DCPP Nuclear Safety Oversight Committee (NSOC). He reported the NSOC is made up of executive-level industry peers and advises the DCPP Chief Nuclear Officer on safety policies. Mr. McWhorter described the meeting as very informative and information was received which the DCISC will consider in following up on its own initiatives. The FFT concluded the NSOC was thorough and comprehensive in its work.

→        Meeting with San Luis Obispo County Department of Emergency Services – Consultant McWhorter reported the FFT met with Ms. Kelly van Buren who has an important new position as the Nuclear Power Plant Program Manager for the San Luis Obispo County Department of Emergency Services (OES). Ms. van Buren oversees the County's programs with DCPP for emergency planning. He reported that in the past Ms. van Buren has attended several DCISC public meetings. Mr. McWhorter reported that Ms. van Buren discussed with the FFT the implementation of the Integrated Public Alert and Warning System (IPAWS) as a back-up to the Emergency Siren System. Consultant McWhorter reported that the FFT provided Ms. van Buren with a copy of the draft Committee Policy on responding to emergencies at DCPP and received her comments and the FFT concluded the Committee should pursue its efforts to develop the Emergency Response Policy.

            On a motion made by Dr. Meshkati, seconded by Dr. Peterson, the March 19-20, 2025, Fact Finding Report was unanimously approved. Dr. Meshkati complimented Dr. Peterson for his efforts concerning workplace seismic safety, which Dr. Meshkati stated is extremely important due to the secondary effects following an earthquake and he stated he was pleased to see and receive the information on the use of AI and that an investigation into this issue will be continued in context of the Open Items List.

D.        The Chair requested Consultant Mr. McWhorter continue and provide a summary report on the March 28, 2025, special fact-finding visit with Dr. Meshkati and accompanied by Dr. Thomas Jordan, Dr. Michael Oskin and Dr. Scott Marshall, the DCISC Seismic Review Team (SRT). Mr. McWhorter reviewed the topics discussed with PG&E during the March 28, 2025 visit as follows:

→        Site Tour to View Geologic Formations – the FFT/SRT drove the access road to the plant inspecting geologic formations particularly the marine terraces and rock formations along the road. Mr. McWhorter mentioned it was instructive to observe how trained geologists look at a landscape and understand and are able to draw conclusions. The FFT/SRT then visited Avila Beach to observe the San Luis Bay Fault as it comes to the surface across from the mouth of Avila Creek and he reported that this is evidenced by different color strata of rock which indicates presence of a different type of rock. The FFT/SRT then visited the hillside across the bridge on the road to Port San Luis to inspect how the layers of rock at that location have been folded, leaving younger rock atop older rock.

→        SRT Question and Answer Session with PG&E Geosciences Staff – Consultant McWhorter stated this meeting involved an intense and highly technical discussion of geologic structure and fault modeling in the area of DCPP and of geodesy, which he stated is the use of geographic data such as GPS position data to monitor and validate geologic and seismic information. Dr. Meshkati reported that the SRT provided a list of questions to the PG&E Geoscience Team prior to the meeting and he described the meeting as a very collegial discussion.

→        Plant Tour – the FFT/SRT toured interior areas of DCPP including the Operating Deck and Control Rooms and the Turbine Building to inspect construction features and steel reinforcement supports that have been incorporated into these structures to address seismic concerns.

            On a motion made by Dr. Peterson, seconded by Dr. Meshkati, the March 28, 2025, Special Fact Finding Report was unanimously approved.

XI        ACCEPTANCE OF MINUTES

            This item concerned review and acceptance of the Minutes of the Committee's February 19-20, 2025, public meeting conducted in Avila Beach and as a Zoom Webinar. A draft of the February 2025 Minutes was included in the public agenda packet for this meeting. Dr. Peterson remarked that the use of bold text in the Minutes is important as it captures and describes some action or commitment on the part of the Committee which is then included on the Committee's Open Items List. The Members and Consultants reviewed the Minutes and provided corrections and substantive changes to certain sections of the Minutes which will be included in the final version of the February 2025 Minutes. The Members and Technical Consultants also conducted a page-by-page review of the February 2025 Minutes and discussed some of the follow-up actions to be taken, provided clarification concerning typographical errors and the accuracy of certain statements in the Minutes, and made editorial comments and changes concerning the draft of the February 2025 Minutes all of which were provided to Assistant Legal Counsel Rathie.

            On a motion made by Dr. Budnitz, seconded by Dr. Peterson, the Minutes of the February 19-20, 2025, public meeting were unanimously approved as revised by the discussion. The Minutes in their final approved version will become a part of the Committee's 35^th Annual Report.

XII      ADJOURN AFTERNOON MEETING

            The Chair adjourned the afternoon session of the DCISC at 4:15 p.m.

XIII     RECONVENE FOR EVENING MEETING

            Dr. Peterson reconvened the evening meeting of the DCISC at 5:00 p.m.

XIV     COMMITTEE MEMBER COMMENTS

            There were no comments by Committee Members at this time.

XV      INFORMATION ITEMS PRESENTED BY THE COMMITTEE

            Dr. Peterson asked Dr. Meshkati to introduce the next topic which was to respond to issues raised by Dr. Peter Bird. Dr. Meshkati reported Dr. Bird, Emeritus Professor of Earth Sciences and Geology at the University of California at Los Angeles, submitted a series of comments to the NRC, to the CPUC and to the DCISC and, prior to Dr. Meshkati's appointment to the Committee, Dr. Bird appeared on several occasions and made statements at DCISC public meetings. Dr. Meshkati stated he worked with the Committee's Consultants and Counsel in the effort to assemble the distinguished Seismic Review Team (SRT) to review Dr. Bird's work. The SRT was led by Dr. Tom Jordan and two of his colleagues. Dr. Meshkati reported Dr. Jordan is the William M. Keck Foundation Professor of Earth Sciences at the University of Southern California and has served as a Director of the California Earthquake Center and he is a member of the National Academy of Sciences. Dr. Jordan was joined in this work by Dr. Scott Marshall, a Professor at Appalachian State University whose areas of research are geodetics and geophysics and by Dr. Michael Oskin a Professor at the University of California at Davis anda graduate of the California Institute of Technology whose areas of research are structural geology, earthquake geology, and geomorphology. Dr. Meshkati reported that with Dr. Kadak's assistance a scope of work for this project was developed and approved by the Committee at its February 2025 public meeting. In the interim he reported the SRT conducted a site visit with an in-person meeting with representatives of PG&E's Geosciences organization and the SRT held separate remote meetings with Dr. Bird and with representatives of the Independent Peer Review Panel created by the CPUC to review seismic safety at the DCPP site and environs. Dr. Meshkati then asked Dr. Jordan to commence the next presentation.

F.         Results of the DCISC's Review of Dr. Peter Bird's Concerns Regarding the Seismic Hazard for DCPP as Evaluated by the Seismic Review Team (SRT) Consultants Dr. Tom Jordan, Dr. Mike Oskin. and Dr. Scott Marshall.

Dr. Jordan stated the charge to the SRT was to conduct a peer review of the various reports submitted by Dr. Peter Bird to the DCISC, the CPUC, and the NRC and to evaluate the assertions made by Dr. Bird. He stated he would now review the four main assertions that constitute what the SRT has termed the Bird Critique.

→        The first being the statement that the hazard to DCPP from thrust vaulting in the Irish Hills has been underestimated because of four false assumptions made by PG&E and removing these assumptions increases the thrust faulting potency, that is, the seismic moment release rate, by a large factor.

→        The second being that Dr. Bird used three independent analytic methods to give values for the total slip rate of shallow dipping thrust faults under the Irish Hills and the rate determined was 2.0 to 2.8 millimeters per year.

→        The third being the major assertion that the January 1, 2024, Noto Peninsula Earthquake in Japan, which had a magnitude of 7.5, is a good analog for a large thrust event to be expected under the Irish Hills.

→        The fourth being that the recurrence interval of a Noto 2024-type earthquake involving the Irish Hills thrust would have a recurrence interval of about 715 to 1,000 years, posing an unacceptable threat to the Diablo Canyon.

Dr. Jordan stated the SRT's Report [which was made available on the DCISC website prior to this public meeting] has four sections including an introduction discussion of the charge and the review process, an annotated summary of the Bird Critique, a set of technical analyses that back up the SRT's discussion of the Bird Critique, and a set of findings and recommendations. He stated the charge to the Committee was to review Dr. Bird's filings, and evaluate his assertions based on the published literature, PG&E reports and expert knowledge across the field. The SRT submitted its Report at the end of May 2025. Dr. Jordan reported an important aspect of the SRT Report was their review of about one hundred basic statements which are included in the Report in a blue font [Dr. Bird' statements] and a black font [SRT comments] and he stated that much of the discussion in the Report is based on five technical analyses which include gravimetric analysis concerning fault reactivation, fault system geometry, geodetic data and models, and comments on the use of the Noto Peninsula earthquake as an analog event.

Dr. Jordan stated the first technical discussion is based on Dr. Bird's assumption that active thrust faulting must explain not only the 0.2 millimeter per year uplift of the Irish Hills, but also a crustal thickening rate that is about six times greater. Dr. Jordan reported the way Dr. Bird determined this was by using the Airy model for isostatic compensation.[18] Dr. Jordan stated this is a local compensation model where any load at the surface is compensated right below it by an increase in the thickness of the crust and what one finds is that the total crustal thickening rate is about six times the uplift rate in the region. However, Dr. Jordan stated this is not a very good model to explain vertical loading in the crust because it ignores the flexural rigidity of the crust and a better and more realistic model is the regional compensation model which is much more widely applied. The regional compensation mode uses flexural rigidity in the crust to spread out the compensation and reduce the Moho depression[19] and he displayed a diagram showing this.

Dr. Jordan stated there are two limits to the regional compensation model, one being that the basic parameter is the so-called elastic thickness of the lithosphere, that elastic thickness can be measured and in the limit where that elastic thickness goes to zero, one gets the Airy model, but where the limit gets very thick this corresponds to what is called the Bouguer compensation, basically a thick plate compensation. He displayed a diagram and stated for the Irish Hills the estimated value of the elastic thickness is about ten kilometers, and that corresponds to a flexural wavelength, a depressional feature, which has a lateral dimension of about 200 kilometers. The diagram he showed described the isostatic response and Dr. Jordan stated that isostatic response function is unity. When one has Airy compensation it is zero, when one has Bouguer compensation he indicated on the diagram where the thickness of about 10 kilometers would fall and stated a flexural wavelength of about 200 kilometers is found. Dr. Jordan stated the important point is that this is much larger than the dimensions of the Irish Hills which have only a dimension of about 15 to 25 kilometers which is well within the Bouguer field. In other words, he remarked, the Bouguer compensation is the correct way to deal with loading of the crust at this scale and the Airy compensation is not and this is shown by a very good study by Langenheim and others about the gravity field that is observed in this part of the world. He displayed a profile going northeast from the plant and stated one can see the gravity anomalies fit extremely well with a model that is dominated by the variation in density between the Neogene sediments and the Franciscan basement and in particular there is a 20 milligal[20] anomaly associated with the Pismo Syncline[21], one of the basic structures in this region that Dr. Bird has used to say that this is over-compensated. In fact, Dr. Jordan stated, this can be very nicely fit with a Bouguer model and so the SRT believes that this is the correct way to describe the gravity in this region.

Dr. Jordan then discussed the analysis and its effect on Dr. Bird's estimate of slip rate. Dr. Bird's basic assertion is that simple Airy isostacy, which gives thickening of about a factor of 6, if that is translated into a slip rate by taking the uplift rate and dividing by the sign of the dip of the fault, and he observed Dr. Bird uses a very shallow dipping fault of 25 degrees and then multiplying by a factor of 6. Dr. Jordan again stated that for small areas such as the Irish Hills, this response to surface loading is Bouguer not Airy, and so the factor of 6 in this equation reduces to unity, and that gives a rate that drops from 2.8 millimeters per year to 0.47 millimeters per year. He observed this rate is further reduced by the fact that the average dip of the main thrust structure beneath the Irish Hills termed the Southwest Boundary Zone, has a dip of about 38 degrees and using that as the dip reduces the estimate further down to about 0.32 millimeters per year. Dr. Jordan stated the SRT's best estimate is based on an uplift rate of about 0.18 millimeters per year and he commented the SRT believes that this is the best estimate available currently and that reduces the slip rate down to 0.29 millimeters per year which is about a factor of 10 smaller than Dr Bird's estimate.

Dr. Jordan stated the second technical analysis the SRT did was on fault reactivation. He stated Dr. Bird's assertion is that high angle reverse faulting in the PG&E Seismic Source Characterization 2024 model (SSC24) is mechanically impossible, stating essentially that faults cannot dip at 50 to 80 degrees as in the SSC24 model because it is mechanically impossible given the present stress regime and he bases that upon the so-called Mohr-Coulomb failure criterion[22] where the failure stress is linearly related to the normal stress, and that when the relationship has a coefficient called the internal friction, that internal friction varies between about 0.6 to 0.85 for many types of rocks, although not all types of rocks. If one looks at that failure criterion for the initiation of new faulting, what is found is that the optimal dip for those types of structures is between about 25 and 50 degrees, if the Byerlee internal friction is used. However, the Mohr-Coulomb criterion assumes that there is a homogeneous and isotropic rock mass and it does not apply to existing fault systems where the strength of the fault is much lower than given by the Mohr-Coulomb criterion. Dr. Jordan observed high angle reverse faulting is commonly observed around the world in inverted sedimentary basins where it is formed by extension and sedimentation and those extensions lead to high-angle normal faulting. But when the tectonic regime reverses and compresses the basin the shortening takes place not on newly initiated faults, but on old normal faults with higher angles and Dr. Jordan stated this can be seen in many places in California including for example in Ventura with the Oakridge Fault which is a high-angle reverse fault that was generated by basin inversion.

Dr. Jordan reported the example the SRT used in its study is from for the Moonlight Fault Zone in New Zealand which has been extremely well studied by Smith et al., in a paper published in 2017, and he reported this is an important region because it is a similar transpressive tectonic regime similar to the Central Coast of California. He stated what one can see is the Moonlight Fault which is a reactivated normal reverse fault has a dip between 60 and 75 degrees which is much larger than would be expected from a Mohr-Coulomb failure. He stated the reason for this has to do with the existence of several factors in terms of generating high angle reverse faulting, one of which is fluid pressure and he displayed diagrams representing the differential stress that is needed to initiate this type of high angle reverse faulting, or any kind of reverse faulting, as a function of the dip angle and also as a function of fluid pressure. He stated that with high fluid pressures one can get reverse fault dips as large as 60 degrees which is not as large as what you see in the Moonlight Fault system, and Smith et al. measured the internal friction associated with the fault gouge. He remarked the fault gouge has much lower strength, it has a static frictional coefficient of about 0.2 millimeters according to measurements and when one includes that 0.2 millimeters in an analysis one can get reverse faulting up to 80 degrees in a dip.

Dr. Jordan stated that there are also other factors besides the fluid pressure and the fault gouge, including the orientation of the faulting, and in a transpressive regime where one can get an oblique faulting and you can have oblique slip that further increases the feasible angles for reverse faulting. He stated the SRT's conclusion was that the reverse faulting at dip angles on the order of 50 to 80 degrees is mechanically feasible in the transpressional environment of the Irish Hills.

Dr. Jordan then introduced Dr Oskin to discuss the fault system analysis.

Dr. Oskin stated that in his presentation he would be reviewing a cross-section through the Irish Hills and he displayed a cross-section visualization of the geologic information at depth constructed from geologic mapping and reported this figure was from the 2014 report by PG&E. He reported the Pismo Rift Basin is a rift basin with lower density sediments that are evident and which extend through most of the Irish Hills. It is bounded by normal faults on both sides, that is by the Edna Fault on the north side and by the San Miguelito Fault on the south side and the transition to compression has folded this basin into a syncline, with an upright fold, the axis of which was shown on the cross section. Dr. Oskin stated associated with the folding there is also reverse faulting and he highlighted this on his diagram and observed the southern edge of the Irish Hills is bounded by the Southwest Boundary Zone, which is actually an array of faults that are spread over a 2-kilometer-wide zone and associated tilting of markers. The San Luis Bay Fault is a particular example indicated on his diagram and he commented that this fault is located just outside the Conference Room where this meeting is now being conducted.

Dr. Oskin reported there is also the Shoreline Fault, located a little further offshore as shown in his cross-section. He reported this is a strike slip fault, so it is moving and it does not quite parallel the Southwest Boundary Zone, so the two systems do cross. Dr. Oskin observed the best available information is that they do cross and the Southwest Boundary Zone continues slightly south of the Shoreline Fault as one goes west to eventually terminate against the Hosgri Fault. He mentioned that all this means that both of these faults are quite close to the plant, which is on the southern edge of the Irish Hills.

Dr. Oskin stated that on the north side of the Irish Hills is located what is termed the Los Osos Trend, more commonly known as the Los Osos Fault. He remarked the SRT opted to call this a trend because the geologic evidence for what is happening along this structure is far more confusing and contradictory. He remarked while there is certainly something going on it might not be a reverse fault and so the SRT is being more agnostic about what to call it.

Regarding Dr. Bird's assertions about what the structure should be beneath the Irish Hills, Dr. Oskin observed first that Dr. Bird asserts that thrust faults should dip 25 degrees beneath the Irish Hills because this is the most favored angle for their initiation and he displayed a diagram from Dr. Bird's report that the SRT annotated with the fault dips measured from the diagram. He reported what is seen is a change of angles from 31 degrees down to 18 degrees.

Dr. Oskin stated Dr. Bird's second assertion is that the throw of the Obispo Formation implies 1.6 to 2.2 kilometers of uplift, and therefore a slip rate over five million years of 0.76 to l millimeter per year. Dr. Oskin stated if this had been symmetrical, then the two faults on either side of the range would give a total thrusting rate of up to 2 millimeters a year, but this neglects internal blind thrusts and therefore it is a lower limit estimate. Dr. Oskin stated Dr. Bird asserts as thrust faults dip, those thrust faults should dip 25 degrees beneath the Irish Hills. Dr. Oskin commented they could, but if one tries to draw faults that actually correspond to the Southwest Boundary Zone, there are two problems. One problem, it would actually project up into the Pismo Basin at depth, which he stated is a very problematic geometry for constructing a balanced cross section that was constrained to help actually build the Pismo Syncline and having a dip that is more parallel to the south limb of this incline is much more amenable to that interpretation. Also Dr. Oskin commented this fault would intersect an oil well control as there is an oil test well that was drilled into the axis of the Pismo Basin which did not encounter this fault. The second problem is the throw of the Obispo Formation at San Luis Bay is 1.6 to 2.2 kilometers, so that matches up offshore from the offshore mapping to the Obispo formation onshore and he stated what the SRT Report points out is that this could also be accomplished by normal displacement on the San Miguelito Fault and he showed this on a diagram. He commented the SRT found a modest amount of slip could explain the position of the outcrops from offshore above the Franciscan rocks on the San Miguelito Fault. He observed a modest amount of slip could also explain the position of these outcrops and there is no reason to explain this with thrust faulting.

Dr. Oskin reported the dip of the San Luis Bay Fault, and more broadly the Southwest Boundary Zone, is important for an understanding of what is going on and he stated he would be reviewing some of the geologic data from the San Luis Bay Fault just offshore of Avila Beach, where there are a number of measurements made available from reports published in the 1990s which he characterized as good observations of the fault dip and which include the outcrop just across the creek and the dips range from 25 degrees to 46 degrees. He stated that collecting this information together from all the published literature and from the seismic imaging offshore, where there is a good image of one of these faults in young sediments, yields an average dip of 38 plus or minus 3 degrees. He reported this is significantly higher than 25 degrees, but also lower than the current PG&E seismic source model.

Dr. Oskin reported that there is an abundant set of outcrops and information on thrust faulting beneath the southern side of the Irish Hills. He observed when looking on the north side to the Los Osos Trend what is most remarkable is how difficult it is to actually corroborate thrust faulting there. He showed two pieces of evidence: a paleo-seismic trench from Lettis and Hall's report (1994) where they were trying to excavate beneath a south facing scarp about a meter high with the expectation that they would find a fault that was inclined toward the south that would be the Los Osos Fault. Instead, Dr. Oskin reported what Lettis found was a fault inclined to the north, which was peculiar and this experiment was repeated in several places and this was the relationship found most frequently. Dr. Oskin stated the result is there is no clear evidence from the investigations except in one location of a fault dipping beneath the range. Instead, the faults dipped towards San Luis Obispo and these are more consistent with the flexural solution where perhaps the Los Osos Trend is due to the transition from a more stable Los Osos Valley to an uplifting Irish Hills, perhaps related to the geometry of the Southwest Boundary Zone and how it is affecting the pattern of uplift above it. Dr. Oskin stated that likewise the seismic imaging project that PG&E funded struggled to find any clear evidence to reveal faults because of the bedrock. He reported that the Franciscan mélange is not well-layered material and so it is really hard to interpret. He observed PG&E made an admirable effort, but it did not really yield much new information about fault dip that is useful.

He then reviewed the additional constraints on the shape of these faults and their rates of slip and remarked that fortunately the Irish Hills is fringed by marine terraces that provide really good markers, because they were cut by the sea level at different times in earth's recent history. There are two main terraces, with the lowest along the Irish Hills, and these terraces have been dated to the last interglacial, Q1 about 80,000 years, and Q2 124,000 years. The Q2 terrace is where the best age constraints are obtained and there has been a lot of effort put in to understanding what the sea level was once it was cut, and it is either the global mean of 6 meters, or perhaps more locally as high as 13 meters. Dr. Oskin stated the SRT weighted these two solutions equally to come up with an uplift rate of .18 millimeters per year and he displayed a diagram with a cross section around the Irish Hills showing the elevation of the shoreline angle or the base of the sea cliff when these terraces were cut. Dr. Oskin observed the terraces are primarily horizontal across the bulk of the Irish Hills around Point Buchon and include the axis of the Pismo Syncline and this indicates that, within the resolution of this data, the Pismo Syncline is not folding today and where deformation is seen along the Southwest Boundary Zone where the terraces step down across several strands of that fault system they are just generally tilting toward the south.

Dr. Oskin stated one of the important questions raised in Dr. Bird's report was whether there is evidence for blind thrust activities of faults that are buried beneath the surface. He added that blind thrusts are not completely blind, they produce folding and uplift and tilting above and the SRT did not see evidence for that within the resolution of this marine terrace data. But the SRT did explore this problem because there certainly are faults within the Irish Hills that cannot be a hundred percent decided as inactive based on this data. He reported the SRT in its review found that the local aerial source model accounts very well for the possibility of a blind thrust rupture within the interior of the Irish Hills and it is a significant hazard contribution. The faults are more parallel to the strike slip fault in the system, but what's most important is that they are distributed through the range with a range of dips and they are both a combination of strike-slip and thrust faulting which is consistent with the overall deformation pattern in this area.

Dr. Oskin displayed a graph of the hazard curve and stated the most significant hazard at 1 Hertz and 1G acceleration is the Hosgri Fault, which is close offshore and has a higher rate of slip. The San Luis Bay Fault which is part of the Southwest Boundary Zone is very comparable to the hazard from the local aerial source. He explained the marine terraces provide one important constraint on how to explain the pattern of the uplift. A second and important constraint is from the geologic mapping effort. He displayed an excerpt from the geologic map compiled for the PG&E 2014 report and highlighted the contact between the upper Pismo formation and older rocks and reported this is the transition from deposition in the basin to the onset of uplift in tilting of the Pismo Syncline with younger rocks distributed in unconformable matter across the older rocks, which implies the onset of tilting, uplift, and erosion of the south limb of this syncline. Dr. Oskin observed this is a very important marker and that was also pointed out by Dr. Bird. This unconformity records the onsets of folding which occurred about five million years ago. What the SRT determined is that the San Miguelito Fault is an inverted normal fault that bounds the Pismo Syncline and the San Luis Bay Fault, a little bit to the south, cuts the footwall of that fault and both of these have acted to uplift the range, and the San Miguelito Fault is critical for folding the Pismo Syncline. He remarked the preservation of these relationships on the south side of the Irish Hills also implies limited Southwest Boundary Zone slip. He noted one cannot have multiple kilometers of over-thrusting to push things out over the sea floor and preserve this relationship and he summed up the fault system analysis as providing an example of a kinematically constrained fault model and stated fault kinematic models are non-unique and other models could be developed to justify different geometries, but what this exercise does is it forces one to look critically at the geologic information and the deformation history over different timeframes to test a model as it is developed.

Dr. Oskin remarked the first piece of the model is a Southwest Boundary Zone fault compatible with the surface and observations with a 40-degree dip and that dip is also important to give the leverage to fold the syncline in its hanging wall. The SRT propose that the Los Osos Trend is a hinge line, formed at the transition from the dipping Southwest Boundary Zone to a flat. At further depth that flat could project to the north beneath the Santa Lucia range and Dr. Oskin commented he believes this is a topic for future work. He commented that this pattern explains the block-like uplift evident from the marine terrace record, so that the marine terraces are just uniformly uplifting with some deformation at the Southwest Boundary Zone and the type of configuration he described would accomplish that.

Concerning folding of the Pismo Syncline, Dr. Oskin commented to do that requires some additional faults and the SRT believes these are reactivated normal faults that were associated with opening of the Pismo Basin and the Pismo hinge line coming up from the hinge between the San Miguelito Fault, the boundary between the San Miguelito Fault and the Southwest Boundary Zone. If one attributes 1.82 kilometers of slip on the San Miguelito Fault, Mr. Oskin remarked one can fold the observed south limb of the Pismo Syncline. That is not all the slip on the Southwest Boundary Zone, however, as there is some additional slip on the San Luis Bay thrust to uplift the base of the Pismo Formation, which is shallow marine sediments, that is a short-cut thrust that bypasses the San Miguelito Fault and therefore bypasses folding of the Pismo Syncline. Dr. Oskin remarked that this explains why one does not see the syncline folding in the marine terraces, the history of this system was older and the buckling of the north limb of the Pismo Syncline also absorbs an additional few hundred meters of slip.

Dr. Oskin stated putting all these components together, the SRT resolved them onto a single Southwest Boundary Zone at depth with 2.6 kilometers of slip over five million years, or a slip rate of .5 millimeters per year. He stated their conclusions on this part of their analysis are that the geological structure of the Irish Hills indicates a moderate dip of the Southwest Boundary Zone that is consistent with fault-outcrop observations and with reactivation of steeply dipping normal faults in its hanging wall to fold the syncline. He added the SRT's best estimate of the slip rate for the southwest boundary zone from the uplift rate of the 124,000-year-old marine terrace is 0.29 millimeters per year. The long-term, five-million-year rate averaged over that time is marginally higher at 0.5 millimeters per year than the short-term rate.

Dr. Oskin stated that some recommendations that come from the SRT's conclusions include future modeling for the seismic hazard to develop a set of kinematically constrained structural models for reverse faults beneath the Irish Hills that can explain the observed folding. He remarked an important and subtle reference frame issue is that marine terraces just record uplift if there's subsidence of the footwall, and that will add to that shorter term slip rate and accordingly the SRT recommends more work to date the low-stand abrasion platforms offshore to get that contribution. He stated there has been recent work redating these marine terraces and the SRT evaluated that closely and believes it is not reliable, but the SRT advises watching that information and reassessing the ages of those terraces if necessary. Finally, Dr. Oskin observed the Los Osos Trend still presents some mysteries and further investigation especially for the potential strike-slip faulting along the Los Osos Trend is important not just for hazard from that fault, but if that impacts the marine terrace uplift pattern that will impact the geometry of the deeper part of the Southwest Boundary Zone in modeling.

Dr. Oskin then called upon Dr. Marshall to discuss the geodetic analysis.

Dr. Marshall remarked that Dr. Oskin reviewed what the geologic record can show and he stated he would now discuss what the geodetic record can tell us. He explained satellite geodesy gives one the ability to look at things that are happening on the day to hour to minute to year time-scale from satellite data and he remarked using the same technology that is used to figure how fast your car is moving on the highway can be used to measure things that move slower than fingernails grow and he remarked these methods are quite accurate.

Dr. Marshall reported Dr. Bird made a number of assertions related to the geodesy in the region and he would first discuss one of the main assertions. Dr. Bird stated that PG&E assumes that geodetic velocities are simply not useful for site specific hazard estimation. Dr. Marshall reported the SRT found that statement to be an over generalization, and if one looks at the PG&E reports what is seen is that PG&E actually uses geodesy in a number of different ways. For example, the 2015 Seismic Source Characterization (SSC15) has two separate sections that are entirely devoted to geodetic analysis in interpretation. He displayed a table from the SSC24 where PG&E reviewed updated deformation models produced by the USGS National Seismic Hazard Model and compared the slip rates from those models to their own SSC slip rates, and the comparison shows that they favorably agree. Furthermore, Dr. Marshall reported PG&E analyzed geodetic data in one-dimensional profiles looking at the different velocities as measured from space. Through use of a graph, he showed PG&E also did strain rate inversions from this data to determine what the principal shortening directions are. Dr. Marshall remarked this graph will be shown to be similar to some of the analyses that the SRT did.

Dr. Marshall stated PG&E operates a GPS receiver near Diablo Canyon that is called Station DCAN and PG&E did an inversion and they reported the shortening rate, but not the direction and the SRT analysis will address this. Dr. Bird also made the assertion that the SSC24 added no geodetic data, even though nine years, the previous SSC15 should have greatly reduced uncertainties and the SRT has found statement to be true. For example, station DCAN has about a factor of eight less uncertainty than it did at the time of the SSC15. Dr. Marshall reported that this in total motivated the SRT to perform a completely new analysis of this updated dataset. He displayed a portion of a dataset from Zeng et al. who published their dataset for use with the USGS National Seismic Hazard Model in 2023 and he commented it is a huge dataset and the velocity scale on the bottom is 40 millimeters per year relative to the stable North American plate. But for the SRT's use Dr. Marshall stated this is actually not very useful because for Diablo Canyon what he was looking for in these data wasn't the velocity, it was the changes in velocity which indicates strain and then to put this data in a local reference frame relative to that station. Dr. Marshall stated he wanted to highlight the San Andreas Fault which is a right lateral strike-slip fault that is moving far faster than all of the other faults discussed. He displayed the exact same velocity dataset, but with all the velocities relative to station DCAN near Diablo Canyon and stated what is seen is a very strong right lateral component from the plate motion in San Andreas Fault together with a rotational component.

Dr. Marshall displayed a depiction of the topography of the Irish Hills with DCPP shown, together with the faults from the Statewide California Earthquake Center (SCEC) Community Fault Model. Dr. Marshall stated Dr. Bird made a number of assertions related to individual selected sites and looking at their velocities relative to station DCAN and Dr. Marshall stated the SRT does not believe this is a good method, nor is it the standard method. If one looks at station CHOR relative to station DCAN, it appears to be moving very fast with station CHOR moving to the right. But if one then looks at station BHRM, it is moving in a completely different direction. Dr. Marshall observed there is clearly some scatter in the data, some due to rotation but some due to the strain that needs to be addressed. He observed the better way to look at this dataset is to create a one-dimensional profile and project the stations and the velocities along the profile directions and the SRT has done this with two different profiles. Dr. Marshall displayed profile A, which he described as perpendicular to the San Andreas Fault and extending all the way past the San Andreas Fault so one can see all the deformation.

Dr. Marshall displayed a graph showing all the velocities relative to Station DCAN, and with stations highlighted within 20 kilometers of the profile line and if they are within that distance they were projected both as parallel to the San Andreas Fault and perpendicular to the San Andreas Fault to look at those two different components of motion and the motion parallel to the San Andreas Fault. He described this as a classic geophysical example of arctangent[23] motion, where one sees the faults from the San Andreas Fault all the way to Diablo Canyon and about 15 millimeters per year of motion was measured which Dr. Marshall stated acts as a sanity check on the data because the geologic slip rate estimates for the San Andreas Fault are between about 24 and 30 millimeters per year, and one should see half of that on one side of the San Andreas fault.

Dr. Marshall reported two different baselines were established and he depicted and described a plot showing DCAN's location, as well as the profile 25 kilometers away where Dr. Bird believes a strain rate of somewhere between 80 and 100 nano strain per year exists. He reported the SRT also extended its analysis out to 50 kilometers, to ensure all the deformations were captured, and found that within that 50 kilometers the stations are all primarily linear which indicates that there are probably numbers of little faults all interacting, because if just one fault was involved it would fall on the arctangent. He reported that the SRT measured about 5.3 millimeters per year, or 106 nano strain and reported the top plot shows the motion that is in the direction of the profile, so this is motion that is perpendicular to San Andreas would not be explained by its motion because that fault is strike slip. Dr. Marshall stated what is seen is within 50 kilometers of Diablo Canyon and the motion is estimated to be very small, 0.58 millimeters per year, but within an error uncertainty there is almost no contraction measured across the Irish Hills and in fact, depending on the profile one takes, and the 25 kilometer estimate is actually extensional which he stated is the opposite of what one would expect for a reverse fault area. Dr. Marshall commented this motivated the SRT to remove this San Andreas Fault related deformation from the signal to see what was left over by getting rid of the San Andreas Fault influence on the data. What was done was to take an existing model, Loveless & Meade, and all of their fault slip rates and all their geometry and to then put that data into a computational model, simulating what kinds of motion would be created and then subtracting from the data. He remarked it is important to note that Loveless & Meade estimated a pretty fast slip rate for the Hosgri Fault, probably because they did not model every fault and the SRT actually changed that to be 1.7 millimeters per year, which is the average at SSC15 and SSC24.

Dr. Marshall pointed out that one can see the creeping section of the San Andreas Fault and normally between large earthquakes, faults at the surface of the earth are stuck or locked, and once one gets down below what is called the locking depth they freely creep. But the San Andreas Fault has this one section that is freely creeping all the way to the surface of the earth, and that creates a really profound deformation signal that needs to be addressed. He used a graphic to show all of Loveless & Meade's slip rates and locking depths and reported these were put into a computational model and simulated what should be the motion at the GPS stations due to the San Andreas and the Hosgri Faults. He remarked that the Hosgri Fault slip rate has very little impact on the solution but what is seen is that there is a very strong right lateral component in the northeast and also a very pronounced zone of extension that is solely due to the strike slip fault. He stated he wanted to clarify that the SRT analysis subtracted this extension off of the Zeng data, which means it is added to the contraction. So, he stated, by simulating the San Andreas Fault deformation, we are actually adding in contraction and then the corrected dataset where all of these motions were subtracted should help better identify local deformation.

Dr. Marshall reviewed the data profile he displayed previously with the corrected data and commented what is seen is the arctangent profile that is parallel to the San Andreas Fault is now gone, which he stated is good because that deformation is removed from the signature, but one also might notice is that there is still a slope and it is not arctangent; it is a straight line and he stated that is the left over deformation that is either due to rotation or strike slip faulting and it is not the San Andreas Fault. The SRT estimates it at about 5.6 millimeters per year which is the prior estimate. When the San Andreas Fault is removed what is left over equates to about 5.6 millimeters per year within 50 kilometers of Diablo Canyon.

Dr. Marshall observed the profile he displayed is parallel or perpendicular to San Andreas Fault, whereas before it showed almost no contraction, and by subtracting the San Andreas Fault deformation there is now significant contraction, about 2 millimeters per year, which corresponds to about 42 nano strains which is far lower than Dr. Bird's estimate of 80 to 100 nano strain. He remarked one can also see that there is considerable scatter within the data. He observed that it is worth pointing out that the local aerial source model has a 70 to 30 strike slip to reverse slip, and the SRT's estimates of shear versus contraction are, for this particular profile, yielding about 2.65 which is close to what PG&E used. He remarked that in the SRT's report there are other profiles that actually suggest an even higher strike slip component and a lesser contraction.

Dr. Marshall commented that everything he showed this evening was one-dimensional analyses, and in the SRT's report some of the caveats of doing one-dimensional analyses are discussed. For the strain field, a two dimensional strain field analysis was done by use of established methods to take the raw data and the corrected data and invert both of those for strain rate using the Sandwell & Wessel method which interpolates the data using elastic theory, not therefore using a regular linear interpolation, ensuring that only components of the velocity that are elastically possible are interpolated which he stated has the benefit of smoothing out the data and removing inelastic motions which are probably not related to tectonics, however, the raw inversions are provided in the SRT's report.

Dr. Marshall stated strain is a tensor, which means it is a matrix and it decomposes into two scaler quantities that make it easier to visualize and understand by looking at dilatation, which is the area of contraction, or extension, and total strain which is the Euclidean norm[24] of the strain rate tensor. He displayed a graphic showing the strain rate inversion of the raw Zeng data. He observed the only thing done was to place the data on a grid and what is seen is now with all of that inelastic motion removed, throughout the entire region there is extension. He observed this has been shown before by Titus and others and in the SRT report it is shown that this effect extends even farther south than what was previously modeled, which is essentially due to that San Andreas creeping section that is a really complicating factor and a huge signal that needs to be dealt with. He commented that the average along the profiles is about 16 to 24 nano strain per year of extension, not contraction, which is problematic for what is left if one does that same inversion on the corrected data.

Dr. Marshall observed that if one looks at the corrected data, what is now seen is a radical change. When the San Andreas deformation is subtracted this induces a lot of contraction through the Irish Hills, although not as much as Dr. Bird has asserted. Dr. Marshall reported there is about 22 to 44 nano strain per year of contraction across those two profiles within 50 kilometers of station DCAN and one can see that almost all the San Andreas Fault signature has been removed except for a small amount that is probably related to creep along the San Andreas Fault that has not accurately been captured, but those affects are local and do not affect the analysis. There are some indications in the total strain rate that are probably related to the strike-slip faulting he discussed previously and Dr. Marshall stated it would be helpful to know more about the slip rates on those faults and that this will be addressed in the SRT's recommendations.

Dr. Marshall commented that the SRT's report goes one step farther to assess if there is what he described as a Dr. Bird-type fault that dips at 25 degrees, and if so what would that look like in the geodetic data, and can geodetic data even resolve the matter. He reported a 25-degree dip was modeled using elastic dislocations, at 2.5 millimeters per year, which is close to Dr. Bird's upper limit. The SRT also modeled a 40-degree dip, which is similar to the kinematically constrained fold model that Dr. Oskin showed earlier, and the flat ramp geometry is close to what was shown earlier, and the team analyzed a 40-degree dip, which he stated is the steepest one could get to still be consistent with the limits of the fold in the fold axis. He commented that all of those data are in the SRT's report, but he displayed a graphic showing the 25-degree dipping model and described the total strain and the dilatation which he stated was all extension versus contraction. He reported all these are model predictions and the velocities are predicted from the model as well, and they were predicted at the current GPS stations to see what they would look like and what is seen is that there is a band of contraction just to the southeast of the modeled fault where that fault would be at the locking depth, which in this case is 12 kilometers, and at 15 kilometers it looks exactly the same, just shifted to the north and a little bit more diffuse. Dr. Marshall stated this data does not show a pattern, but it might be that the data just doesn't have low enough uncertainty to resolve this and the next question asked was what about the spatial distribution of stations, are there enough GPS stations to even have a hope of resolving this kind of feature? Dr. Marshall reported that all of these model predictions were taken to pretend they were actually GPS observations and inverted for straining to see if the patterns can be recovered. He commented that non-geophysicists might look at this data and say that it is terrible, but overall, he stated one sees a pattern in that band of contraction, the band of extension, and the band of total strain in the right location. Dr. Marshall stated the SRT concluded that the geodetic data has sufficient special resolution to resolve these strain signatures if they were there, but the velocity uncertainties are thought to be too large to be able to address this. To illustrate that point further Dr. Marshall returned to the very first profile he used showing the San Andreas Fault parallel and the San Andreas Fault perpendicular and asked rhetorically what if all of those different models with the dipping faults were plotted on that profile what would they look like? He stated they would look as if all of the lines fell within the uncertainties of the data and so he observed geodesy alone cannot resolve the individual slip rates of these faults. Dr. Marshall stated what is needed is a comprehensive three-dimensional model of all the faults within the area to make sure that motions are not predicted that are beyond the constraints of the GPS and that is part of the SRT's recommendations.

Dr. Marshall, in concluding this part of the presentation stated that, over all the SRT's findings from geodesy are that the strain rates that were calculated very much depend on how one corrects for deformation along the San Andreas Fault and so the SRT recommends that this be a focus of future efforts. The corrected GPS data show a significant right lateral shearing across the Irish Hills and beyond, but the contraction is really more like 40 to 20 nano strain per year, which is far less than Dr. Bird suggests. GPS cannot individually resolve fault slip rates, but with a comprehensive three-dimensional model the SRT is confident that one could at least determine if the SSC slip rates go outside of the GPS bounds. Dr. Marshall reported the SRT's recommendations are that PG&E should follow up on the SRT's preliminary work with a more complete study of the available GPS data. The fault slip models should be developed into kinematic and mechanical models to see if all these SSC slip rates are within the bounds, and it would be very helpful to know more about both the Rinconada and the Huasna Faults and potentially about the strike slip along the Los Osos Fault to be able to better model this data.

Dr. Marshall then called on Dr. Jordan to continue the presentation.

              Dr. Jordan stated the final technical analysis involved the 2024 Noto Peninsula earthquake which Dr. Bird has nominated as a good analog for large thrust faulting beneath the Irish Hills. Dr. Jordan reported that Dr. Bird calculated a recurrence interval for a Noto 2024-type event as being 715 to about 1,000 years, which would lead to an unacceptable risk to DCPP.

              Dr. Jordan stated the Noto Peninsula earthquake was an unusual event involving a very high stress drop, very large displacements, very high shaking intensities, and up to an average displacement on the order of four meters which is about twice what Dr. Bird suggests. Dr. Jordan observed much of that result was due to the high stress drop in the event that generated high seismic motion and the Noto 2024 event was a very long rupture, with a very high length-to- width aspect ratio. He displayed a diagram which plotted dip-slip events and plate boundary events worldwide and observed the Noto Peninsula event lies outside that field because it is so long relative to its width. Dr. Jordan commented he believes typical thrust faulting would have much smaller widths on the order of 20 to 80 kilometers, rather than 150.

              Dr. Jordan reported the other aspect of the Noto 2024 event is that there is a very good correlation between the uplift rate as shown on the plot, which is taken from synthetic aperture radar data, and the total fault slip model which he showed and he commented that where you have maximum slip you also have the maximum uplift and that means that uplift is a proxy for slip. Dr. Jordan stated there is a good correlation between the uplift during the earthquake and the uplift rate and the two look the same with the highest uplift being on the northwest side of the Noto Peninsula. It then tapers down to a much smaller value as you go to the southeast and what is seen on the topographic profile is that the block has been tilting significantly and he reported that this is quite different from the rigid uplift that one sees in the Irish Hills. He stated the uplift rate is a proxy for the slip rate and a calculation can be performed to compute the recurrence interval of this event from the co-seismic uplift and the uplift rate by taking the co-seismic uplift and dividing by the uplift rate. The co-seismic uplift is about 2 meters. The uplift rate for this particular region is about 0.7 to 1 millimeter per year, but you also have to determine what else is contributing to that uplift. If one simply assumes that only those sorts of characteristic events, which recur repeatedly lead to the uplift then there is a factor of 1 in front. On the other hand, if there are smaller events and those smaller events are also contributing to the uplift, then that factor can increase to a factor of two. So, he commented depending on how one chooses that factor, you get recurrence intervals that range from 2,000 to 3,000 years for that factor of one, to up to 4,000 to 5,700 years if you take the full Gutenberg- Richter model and use that model it gives about a factor of two in the increase in the recurrence interval and these numbers are approximately what the Japanese have estimated for this particular type of event in this particular region.

              Dr. Jordan stated if this model is translated to the Irish Hills by substituting the uplift rate of the Irish Hills from 95% confidence interval based on what Dr. Oskin reported is 0.12 to 0.24 millimeters per year, and that gives a recurrence interval that ranges from an average of approximately 12,000 years to approximately 22,000 years, depending on how one chooses the factor that accounts for the smaller events. He stated if you take the Noto Peninsula event as a characteristic earthquake, the best estimate of the recurrence interval is the Gutenberg-Richter model that would correspond to a recurrence interval of about 22,000 years which he reported is about a factor of 20 larger than Bird's rate of 715 to 1,000 years. Dr. Jordan stated the SRT does not believe it is appropriate to take the Noto Earthquake as a characteristic event and there are a number of reasons for that having to do with tectonic differences between the Noto Peninsula and the Irish Hills. Including that the total uplift rate is about five times larger in the Noto Peninsula than it is in the Irish Hills and there is much larger rate of historical seismicity than is seen in the Irish Hills region. He reported the tectonic deformation of the Noto Peninsula has essentially pure compression with a very little bit of shear, whereas the Irish Hills region and the San Luis Pismo block have a significant component of right lateral shear. Dr. Jordan observed one of the key differences is the length of the Noto Peninsula faulting, which is about the length of the southwest boundaries on faults that would be the place where one could get such a large faulting, so he stated they are geometrically incompatible. The large prominent fault scarps seen offshore of the Noto Peninsula area are not seen offshore of the Irish Hills. Finally, Dr. Jordan reported the rapid tilting of the Noto Peninsula is on a larger scale than the lock-like uplift of the Irish Hills and this is important because it points to a difference in the character of the faulting. In the case of the Noto Peninsula what this indicates is the fact that you have a large block that continues to tilt and a thrust fault goes to greater depths than is the case of the Irish Hills, and the Noto area has a sort of flat ramp geometry that Dr. Oskin discussed and that flat ramp gives block-like uplift and therefore there is a fundamental difference in sort of the faulting configuration between the Irish Hills and the Noto Peninsula.

              Dr. Jordan displayed a map showing the Los Osos Domain with a 15 x 150 kilometer area superimposed that would be occupied by a Noto-type rupture and he stated one can see a Noto-type rupture just does not fit within the Los Osos Domain. He commented that the SRT expects that on the west side where it intersects with the Hosgri Fault in the Southwest Boundary Zone, the faulting could not continue and he commented perhaps it could continue on the southeast side, but it would then have to cross the boundary between the Los Osos Domain and area to the east. So, the SRT concluded that based on the analogous characteristics of the Noto 2024 event, that it is not a very good or very suitable characteristic earthquake for thrust faulting beneath the Irish Hills.

              Dr. Jordan reported with these comments this concludes the SRT's technical analysis and the SRT would now review the four main assessments of the Bird critique.

              The first being that Dr. Bird claims that PG&E has underestimated the hazard at the plant from thrust faulting because it made four false assumptions, and that removing these assumptions will increase the thrust faulting potency, that is, the moment release, by a large factor. Dr. Jordan summarized the SRT response and reported removing these four assumptions would not actually have an impact on the hazard estimates and certainly not at the level that Dr. Bird suggests. Dr. Jordan stated in reviewing Dr. Bird's estimates of slip rates the SRT found in the case of the so-called method one, the isostatic method, the Southwest Boundary Zone slip rate based on the best data is on the order of 0.29, plus or minus 0.07 millimeters per year which is about an order of magnitude smaller than Dr. Bird's estimate of 2.8 millimeters per year. Method two, which involves the history of faulting since approximately five million years ago, for which the SRT obtained a rate of 0.5 millimeters per year which is significantly less than Dr. Bird estimates by about a factor of four. It also indicates that there may be a slight slowing down of the compressive deformation as a function of time. Finally, Dr. Jordan reported concerning method three, using the geodetic method, as Dr. Marshall has pointed out, the best estimate that the SRT has of compression across the Irish Hills is about minus 20 to minus 40 nano strain and that compares with minus 80 to minus 100 from Dr. Bird's estimates and this also is a significant difference. Dr. Jordan reported that to translate that to a slip rate one must make a number of assumptions, including that the strains are elastic and that they are released only by slip on the Southwest Boundary Zone and if that is assumed it produces an estimate of about 0.95 millimeters per year which the SRT believes is an upper bound.

              Dr. Jordan stated concerning the SRT's overall assessment of the four main assertions made by Dr. Bird, that removing the four false assumptions in the development of a revised SSC would have little or no impact on the hazard estimate. With respect to the rates, the slip rates that underlie the Irish Hills are about an order of magnitude smaller than Dr. Bird estimates and in terms of the Noto Peninsula Earthquake, the SRT does not believe it is a suitable event to use as a characteristic event for the Irish Hills and if used as that characteristic event, the recurrence time would be about twenty times longer than Dr. Bird has estimated. Dr. Jordan summed up the presentation by observing that the best available science does not support the four main assertions of Dr. Bird's Critique. He reported in its Report the SRT has collected new information and done new calculations which perhaps throws a light on the SSC model and perhaps should be considered in terms of the hazard implications with respect to this model.

              Dr. Jordan stated the SRT has in its report provided a list of findings that are relevant to the SSC and could be used in terms of improving the SSC and he asked Dr. Oskin to summarize the SRT's four recommendations from the fault system analysis.

Dr. Oskin reported the recommendations to PG&E include:

[The SRT's recommendations were restated, numbered, and fully set forth and given in their final form in Version 5.5 of the final "Review of the Bird Critique" and for clarity they are included here italicized text in brackets]:

Develop kinematically constrained structural models for reverse faults underneath the Irish Hills that incorporate all of the information about deformed marker horizons in its hanging wall.

[â?– Recommendation 1: The SRT recommends the development of a set of kinematically constrained structural models for reverse faults underlying the Irish Hills that can explain the folding observed since 5 Ma.]

→        Further constrain rate of subsidence in the offshore south of the Irish Hills to constrain that component of footwall subsidence that contributes to the slip rate of the Southwest Boundary Zone.

[â?– Recommendation 2: The SRT recommends dating of low-stand abrasion platforms offshore, south of the Irish Hills, to further constrain the rate of footwall subsidence and its contribution to the SWBZ slip rate.]

→        Monitor the IRSL-dating efforts and reassessment, if necessary, of the marine terrace ages.

[â?– Recommendation 3: The SRT recommends monitoring of IRSL-dating efforts and reassessment, if necessary, of the MIS 5 age assignments for the Q1 and Q2 terraces surrounding the Irish Hills].

→        Conduct further investigation of potential strike slip faulting along the Los Osos trend and its impacts on the pattern of marine terrace uplift.

[â?– Recommendation 4: The SRT recommends further investigation of potential strike-slip faulting along the Los Osos trend and its impacts on the pattern of marine-terrace uplift.]

→        Continue the geodetic analysis of the GPS with further study.

[â?– Recommendation 5: PG&E should follow up the SRT's preliminary work with a more complete study of the available GPS data.]

→        Develop the fault slip models that underlie the SSC into fully three-dimensional models that have all the faults and all the slip rates to see if they fit within the GPS data.

[â?– Recommendation 6: The fault slip models that underlie the DCPP SSC should be developed into kinematic and mechanical models that can predict the interseismic deformation and can thus be directly tested against the GPS data.]

→        Review the ratio of shearing versus contraction using geodesy to help constrain the result. [â?– Recommendation 7: PG&E should compute the relative contributions of strike-slip and reverse faulting to the regional deformation predicted by the SSC24 slip models and compare the values with the geodetic constraints.]

→        Investigate the Rinconada, Huasna and Los Osos Faults strike slip rates to help model those new geodetic data.

[â?– Recommendation 8: Geologic slip-rate information should be acquired from the Rinconada and Huasna faults to permit better modeling of the shear component evident in the GPS data.]

→        Conduct a series of modeling experiments to ascertain the sensitivity of the model of the hazard for DCPP if modifications are made as recommended by the SRT, which can be done through sensitivity analysis rather than full scale new modeling. This includes decreasing the mean dip of the Southwest Boundary Zone faulting to agree with the observed average which the SRT found to be about 38 degrees which is somewhat less than the PG&E number; and reweighting the fault geometry models, in particular the southwest vergent model should receive a higher weight than outward vergent model, instead of at present weighting them the same, and re-evaluate the hazard associated with the Los Osos trend.

[â?– Recommendation 9: PG&E should conduct modeling experiments to ascertain the sensitivity of DCPP hazard to the SSC modifications recommended by the SRT.]

Dr. Peterson remarked the Committee did not pose any questions during the course of the SRT's presentation because each Member of the Committee and the Consultants had an opportunity to review the draft of the SRT's detailed report and to provide feedback to the SRT which was considered and, at the SRT discretion, incorporated into the final report. He then opened the comment period first to Dr. Peter Bird who had previously requested the opportunity to address comments on the SRT's report and was granted time to do so.

Dr. Peter Bird appeared via the Zoom webinar and he thanked the Committee for this opportunity to speak. He emphasized that although he may not be able to present all his points in this presentation, he previously presented detailed written comments to the Committee. [The Committee received a document entitled "Technical Response to the Review of the Bird Critique with Recommendations for Further Actions" dated June 6, 2025.]

Dr. Bird stated he appreciated the SRT's detailed review of his comments and he observed there are a number of areas of agreement between him and the SRT and he stated he identified 33 cases of either such agreement or qualified agreement and he commented that these may perhaps be considered points of lesser importance, but there were many of them. He further stated that he and the SRT also agree on the conclusion that PG&E in the development of its fault models in 2015 which was never updated and which he stated was deficient because it did not include neo-tectonic deformation modeling or finite-strain historical modeling to explain the syncline and Dr. Bird remarked that he and the SRT are in agreement that these deficiencies should be corrected very soon.

Dr. Bird observed his differences with the SRT fall within the four technical areas outlined by the SRT that he contends, while the SRT's technical analyses were impressive, in each case they were based on an elementary mistake made at the beginning of the analyses or even before the beginning of the analyses. He displayed what he described as a well-known map showing the Irish Hills and the isostatic gravity anomaly in the Irish Hills region and the adjacent San Luis Range which he stated have negative isostatic anomalies. He stated the SRT objects to the idea that the Irish Hills cannot be isostatic because elastic plate theory predicts that the lithosphere will be too strong to allow it. Dr. Bird stated the lithosphere here is seismogenic in that it experiences microearthquakes and contains active faults and therefore it is not elastic. He remarked people should be cautious about predicting what a theory will tell us.

Dr. Bird stated another important problem is shown on the map he displayed which clearly shows that the isostatic gravity anomalies are negative which means that there is more than perfect isostatic compensation, something like 120% to 140%, and that is a fact. PG&E's models and also the SRT's models would predict a positive isostatic gravity anomaly which is not observed anywhere in the Irish Hills or San Luis Range. Therefore, Dr. Bird maintains that there has to be serious consideration of an isostatic model that would predict at least six times more seismicity.

Dr. Bird stated another point about gravity is that the SRT maintains the low-density sedimentary rocks in the Pismo Syncline explain the negative gravity anomaly and he agrees that this does explain a part of the anomaly including the reason why the southern area of Irish Hills have a more negative isostatic gravity anomaly of approximately minus 23, relative to the northern area of the Irish Hills, at approximately minus 10. While he agrees this may be true, it is a minor point because the more important point is that all of the Irish Hills and the San Luis Range have negative anomalies.

Dr. Bird displayed a figure depicting what he described as the great contrast between the steep reverse fault dips that PG&E assumed and Dr. Bird's preferred dips and also showing an estimate of the throw on the Southwest Boundary Zone fault over the last five million years which he reported is more than one kilometer. He observed the SRT objected to his method for estimating the slip rate by using the throw on the fault and the SRT's argument is that that unit Tmo may have been previously offset by Miocene normal faulting. But he stated the problem with the SRT's objection is that the only faults between these two offset bodies of Tmo are either strike-slip, the Shoreline Fault has no vertical offsets, or they are normal faults that dip north and if those normal faults offset Tmo they would have offset the north side down and Dr. Bird stated that the north side is found up which means that if there was previous normal faulting, the slip rate computed by his Method Two would have to be increased, not reduced, and he stated that slip rate is only a lower limit.

Dr. Bird stated regarding the subject of steep reverse faulting being mechanically impossible and he agreed that he had used an unwise phrase and should have said that they are what the SRT favors. He stated first, one needs a very weak fault gouge and it would have to survive an intense Miocene metamorphism and remain weak and fine-grained up to the Pliocene; and second, there is a serious problem in that there are less steeply dipping thrust faults in the Franciscan Complex that were created during the secretion to North America which are competing faults for reactivation and they would reactivate at a much lower stress level, limiting the stress level and blocking the reactivation of the very steeply dipping faults that PG&E relies on for their SSC.

Dr. Bird stated he would now take up the matter of Global Positioning System (GPS) data and he displayed a close-up plot in the area of Station DCAN from the USGS' compilation by Zeng (2022), and reported he made no alterations except to change the velocity reference frame, choosing the velocity reference frame in which Station DCAN is not moving and the Irish Hills are not rotating. He observed in that reference frame one can see rather clearly that Station CHOR is converging with Station DCAN and Station 2110, which is near Point San Luis and is converging even more rapidly with Station CHOR. He stated he simply took the average of those two convergence rates, 1.8 millimeters per year, as the issue he wanted to emphasize and he did not calculate strain rates. Dr. Bird stated the SRT objects and maintains that before interpreting differences between inter-seismic GPS velocities the velocities must be corrected for effects of elastic strain accumulation on distant faults and he admitted that this is true, but he stated this is not important in this case. It is not important because the two stations are close together and their velocity difference is insignificant. He stated the correction methods attempted by the SRT are deficient in more than one way; first, in order to do this correction for elastic strain accumulation on distant faults the SRT chose the worst model available, one that was not accepted by the USGS, instead of one of the four models that were found acceptable for use in the National Seismic Hazard Update. He stated a more serious criticism is that the SRT used various algorithms that have the effect of smoothing the strain rates over an area larger than the Irish Hills. He stated as the Irish Hills have a very unique shortening rate in a very small area, any regional smoothing is going to kill that signal, but that is the important signal from a seismic hazard point of view. He commented they are only 50%, or 25% of his estimate, but those are inappropriate and misleading.

Dr. Bird remarked that the SRT objects and states that if horizontal shortening is found it must be partitioned between thrusting and strike-slip faults, but actually the SRT did not try to do this formally. He observed that this is a true point, but again it is not important in this case because there is very little indication of strike-slip faults in or near the Irish Hills except for the very slow-moving Shoreline Fault which is slightly outside the area of the Irish Hills.

Concerning the assertion of the Noto Peninsula Earthquake not being an analog for DCPP because its rupture was too long, Dr. Bird stated this is certainly true, however, it is easily corrected for. He stated the Noto Peninsula earthquake had a bilateral rupture and the relevant southwestern part of the rupture can be easily isolated either in space or in time, giving an analog earthquake with a shorter rupture, somewhat smaller moment, and a somewhat smaller magnitude. Dr. Bird stated this would really have no effect on his conclusions because the northeastern part of the rupture only prolonged the shaking on the Noto Peninsula and it contributed nothing to its extremely high peak ground accelerations which were all due to the southern part of the rupture.

Dr. Bird observed that the SRT has raised another interesting point in that if the Noto Peninsula earthquake is accepted as an analog, this means that the slip should be four meters according to a recent paper and not two meters. He stated this is an interesting matter to be studied in the future because if that is true the larger slip would reduce his seismic core damage frequencies for Diablo Canyon by 50%. However, Dr. Bird stated that the seismic core damage frequencies would still be 17 to 20 times higher than the rates that PG&E reported to the NRC and would still represent a serious problem. Furthermore, he commented that before that larger slip is accepted it needs to be clarified as to why the seismic movement estimated by Xu et al. is twice as high as that estimated by the USGS which is usually considered the authority on these matters.

In concluding his comments, Dr. Bird stated he would make some observations concerning the new ramp-flat stress model that the SRT created during its study and he remarked he likes many things about the model and sees it as a good start on explaining the formation of the Pismo Syncline and it agrees in many ways with his analysis of what is occurring in the Irish Hills. As an example, Dr. Bird observed the SRT estimated a start time of 5.1 Ma which agrees with his of 5 Ma. The SRT's average dip of 17 degrees, including the ramp in the flat, is even lower than his proposed for low angle thrust faults and if the SRT is right then the Southwest Boundary Zone had normal slip in the Miocene and this could actually increase Dr. Bird's slip rate in the Pilocene-Quaternary time period as calculated by Method 2. He remarked the SRT's model also contradicts a key assumption of the PG&E model which is that the fold is finished and dead. Dr. Bird remarked in his estimate the most important point is that if this ramp-flat model explains the formation of the Pismo Syncline, then that fault must extend west at least as far as the syncline. Therefore, it must extend west at least to Point Buchon and probably out to the Hosgri Fault and that implies that there is an active thrust fault immediately below Diablo Canyon and he remarked on that point he and the SRT seem in agreement and are just quibbling about the slip rate.

Dr. Peterson thanked Dr. Bird for his comments and Dr. Peterson remarked that tomorrow morning the Committee will review and discuss the nine recommendations made by the SRT. Dr. Peterson stated he would be interested in Dr. Bird's thoughts about those recommendations, as well as any additional recommendations for additional work that Dr. Bird might have. Dr. Bird replied that he included a half page of recommendations at the end of his written comments.

Dr. Peterson then asked the members of the SRT if they had any thoughts or comments in response to Dr. Bird's remarks. Dr. Jordan confirmed the SRT has had an opportunity to review the document submitted by Dr. Bird in response to the SRT report and the SRT does have comments on each of points raised by Dr. Bird, but Dr. Jordan stated that based on reviewing that document carefully the SRT sees no reason to modify any of the statements in its report.

Dr. Peterson requested that Dr. Bird's written comments and viewgraphs be entered into the records of the Committee and commented that a response to the comments provided by Dr. Bird should be forthcoming.

Dr. Peterson stated this would be an opportune time for PG&E to discuss in particular the recommendations from the SRT's Report because they become potential future work for PG&E.

Dr. Chris Madugo a geologist with PG&E's Geosciences Department was recognized. Dr. Madugo stated that as PG&E received the SRT report only nine days ago his organization is still evaluating it, but he stated he has some initial comments.

In terms of the recent contentions, that is, the contentions filed by San Luis Obispo Mothers for Peace, Friends for the Earth and the Environmental Working Group, that the DCPP seismic source model developed through a SSHAC Level 3 process[25] in 2015, with a follow-up SSHAC Level 1 process in 2023 to 2024, led to a significant underestimation of seismic hazard and risk Dr. Madugo stated PG&E believes that those contentions have been thoroughly reviewed and discounted through multiple reviews. He reported in 2024 PG&E reviewed the initial contentions raised by Dr. Bird through its seismic hazard update and in that review devoted a full chapter to evaluating Dr. Bird's contentions, including in that review group experts within the Geosciences organization as well as external consultants. He reported a participatory peer review panel also reviewed Dr. Bird's contentions and an additional level of participatory review was provided by UCLA's B. John Garrick Institute for Risk Sciences. He reported the NRC has also reviewed Dr. Bird's contentions on multiple occasions and in the recently issued Proposed Director's Decision the NRC rejected the contentions.

Dr. Madugo stated from his review of the SRT's Report, the main contention raised with the NRC by the San Luis Obispo Mothers for Peace, Friends of the Earth, and the Environmental Working Group that the hazard and risk to DCPP are so high that the plant should be closed immediately have been discounted. In terms of next steps, he reported PG&E is unique in terms of having a Long-Term Seismic Program (LTSP) wherein new proponent models and new published research is continually evaluated and he reported the LTSP is an operating condition under the DCPP licenses from the NRC. He confirmed the SRT interpretations, models, and proposed modifications to the SSC model will be evaluated by PG&E's reviewers to assess whether they are technically defensible and he reported that since 2024 PG&E has been considering expanding its reviewer group to include structural geology and geodesy experts. Dr. Madugo reported that the SRT's recommendations for model changes and additional research will be evaluated through hazard sensitivity studies to assess the hazard significance. He observed, in terms of the SRT's nine recommendations, one of the most important is to see if the proposed changes matter significantly so as to increase the hazard and the risk. Dr. Madugo gave as an example of this hazard and risk assessment, the Southwest Boundary Zone. He reported PG&E's SSC15 report included a sensitivity study of the Southwest Boundary Zone as part of the model and if one were to put 100% weight on the Southwest Boundary Zone model, the mean hazard would be approximately the same. It would not increase significantly because the slip rate on Southwest Boundary Zone is low relative to the Hosgri Fault, which is an order of magnitude higher and drives the DCPP hazard assessment.

Dr. Madugo reported that prior to PG&E receiving the SRT's Report and its recommendations, work was proceeding as part of PG&E's normal processes under the LTSP to begin to address comments by the IPRP evaluating some of Dr. Bird's comments. He displayed a slide listing the SRT's recommendations and highlighted the work that PG&E has commenced to address and consider the SRT's recommendations. He mentioned that in terms of developing a kinematically and structurally constrained model, PG&E began developing a scope for the initial development of a simplified structural model and is also reviewing new research concerning the Santa Maria Basin which was requested by the IPRP and Dr. Madugo stated there will be a field trip on that subject later this summer.

Dr. Madugo stated that in terms of dating the low-stand abrasion platforms, PG&E recently met with the USGS to explore the potential for doing additional dating under the PG&E Cooperative Research and Development Agreement with the USGS. In terms of monitoring infrared stimulated luminescence dating, PG&E has already completed a pilot project to explore the use of new dating methods and their applicability to the hazard at the plant site and will continue to monitor new developments in that field. He remarked that the dating method is an issue for the entire community interested in dating marine terraces.

Dr. Madugo remarked concerning further investigation of the Los Osos strike-slip faulting potential or the type of faulting that is occurring on the Los Osos area he reported PG&E is funding a USGS project to publish Los Osos area offshore research that was completed in 2016, and this will be updated with new data and that should be completed in the next year. In terms of following up on the SRT's preliminary geodetic analyses, PG&E has already spoken with the USGS to develop a scope for that work and PG&E is expanding its expert review panel to include geodesy, structural geology, and modeling experts.

Dr. Madugo reported PG&E is actively upgrading the GPS network around the Irish Hills which is operated by the USGS. In terms of the recommendations concerning sensitivity studies Dr. Madugo remarked this is one of the most important recommendations and PG&E is in the process of updating the source model so that it will have a simplified source model that can be quickly used to run sensitivity studies. He reported PG&E is also updating tornado diagrams based on the 2024 model.

In summarizing and concluding his remarks Dr. Madugo stated PG&E now has a significant amount of work ongoing that would address some of the SRT's recommendations.

Dr. Peterson observed that there is a significant likelihood that the SRT's recommendations will help to guide and to shift the direction of future work in assessing the seismic hazards at the DCPP site and he then called for public comment.

XVI     PUBLIC COMMENTS AND COMMUNICATIONS

            Dr. Peterson invited members of the public to address the Committee on matters not on the agenda for this meeting.

            At the commencement of this evening session, Mr. David Weisman of the Alliance for Nuclear Responsibility addressed the Committee and stated he had recently received a statement from U.S. Representative Salud Carbajal, who represents areas on the Central Coast in Congress, which pertained to the item on the Committee's agenda earlier concerning the Presidential Executive Orders affecting the NRC. Mr. Weisman read from Congressman Carbajal's statement in which the Congressman characterized the Executive Orders as a reckless decision that could weaken the NRC's ability to protect communities near nuclear power plants and confirmed the Congressman's opposition to rolling back safety and environmental protections.

Dr. Gene Nelson with the group Californians for Green Nuclear Power was recognized. Dr. Nelson stated it is his belief that Dr. Bird simply took something that was scary and then tried to jam it into the Irish Hills and his group took what he described as the unusual step of filing an objection to San Luis Obispo Mothers for Peace, Friends of the Earth, and the Environmental Working Group's 10 CFR 2.206 Petition to the NRC focusing on the issue of an improper analogy. He remarked because the Noto Peninsula is actually in the process of beginning a subduction zone, it is being bent and this is not at all representative of seismic setting for the Irish Hills. Dr. Nelson commented on the large volume of material Dr. Bird has produced and he observed it seems to Dr. Nelson that Dr. Bird develops his position and then attempts to provide support for that position.

Mr. John Geesman on behalf of the Alliance for Nuclear Responsibility was recognized. Mr. Geesman stated while he has not had the chance to review the full SRT report he observed that it is now almost three years following the enactment of SB 846, which called for a seismic update of the plant. He stated he realizes that some of these issues will never be fully resolved, but he observed we should be cognizant of the amount of time that has passed since the Legislature asked PG&E for an update. Mr. Geesman commented he was quite interested in the SRT's suggestion about increasing the emphasis on the southwest vergent mode and its recommendation for future work. He reminded the Committee that approximately eleven years ago the Alliance for Nuclear Responsibility's expert, Dr. Douglas Hamilton, presented that very recommendation during the SSHAC review process and also to the IPRP and he stated his client would be interested in seeing the follow up to that work.

Mr. Geesman stated that although he has raised the point several times and will continue to do so until it's fully addressed, there is the question that initially prompted by the California Energy Commission's recommendation in 2008 that PG&E do a deterministic review of what a San Simeon thrust earthquake directly beneath the plant would produce in terms of impact on the PG&E ground motion models. He stated to his knowledge that review has yet to be performed. He remarked that he has some skepticism on this point because he believes that PG&E was probably sufficiently responsive at that time and would have performed the review and it may be that it has not been released publicly. Mr. Geesman reported he has come before the Committee before and requested information on that review without a response. He acknowledged Dr. Meshkati's assistance earlier this year in going to his appointing authority, the California Energy Commission, to ask about the matter, but the Energy Commission has indicated it will defer to the IPRP for a review and the fact remains that seventeen years after the Energy Commission initially made its request, it has still not been done. Mr. Geesman remarked that Dr. Bird has concluded concerning the matter of the prospect of a thrust fault directly beneath the plant and there is a study that was ordered seventeen years ago that still has not been performed and he remarked the Committee ought to make certain that it will be.

With Dr. Peterson's consent, Dr. Madugo was again recognized and Dr. Madugo confirmed that in preparing its response PG&E reviewed Dr. Hamilton's report.

Ms. Patricia Colon, a resident of San Luis Obispo since 1976 was recognized. Ms. Colon commented that the erudite data presented is wonderful, however, she wonders if mother nature is listening. She remarked the residents of Pompeii and Herculaneum did not have data and were caught by surprise and buried alive. She remarked the strain rates and the strike-slip faulting on the multitude of earthquake faults that were outlined are jaw dropping and she wonders what contingency plans are in place to evacuate the people from San Luis Obispo. She commented that circumstances have changed over time and the emergency plan that was set in place decades ago is totally out of date and irrelevant. She stated she wonders why the citizens of San Luis Obispo are put at this risk by an antiquated nuclear power plant that it was agreed would be shut down in 2024 and 2025.

Ms. Linda Seeley, a resident of Los Osos and a member of San Luis Obispo Mothers for Peace, was recognized. Ms. Seeley reported the exchange between the SRT and Dr. Bird was mesmerizing to her, not because she understood the technical nuances but because of the fact that there is so much ground-level disagreement on what the situation is with respect to the earthquake faults at Diablo Canyon and this is of incredible concern to her and she observed the Committee has a huge responsibility from the California Public Utilities Commission concerning safety at Diablo Canyon. She wondered how there can be so much disagreement concerning the possibility of earthquakes, that is, between 700 years and 25,000 years. She asked if PG&E were applying for a license to build a nuclear power plant at Diablo Canyon today whether it would be given a permit to do so because of all of the earthquake faults and she stated the task of the Committee is to err on the side of safety and this is the charge of the whole community because a nuclear meltdown anywhere is a nuclear meltdown everywhere and she stated she hopes the Committee will not take this matter lightly.

Ms. Sherry Lewis, a member of San Luis Obispo Mothers for Peace was recognized. Ms. Lewis stated she listened but understood almost none of the discussion this evening but what struck her is the SRT's comment that what they heard from Dr. Bird did not change anything in the SRT's Report which she stated seemed striking to her. Mr. Rathie reported that the SRT and Dr. Bird each exchanged and reviewed copies of their respective reports prior to the meeting.

Dr. Budnitz commented in response to Ms. Seeley's remarks and reminded Ms. Seeley that some months ago Ms. Seeley again asked the Committee to take this issue seriously. Dr. Budnitz stated that the Committee has indeed taken the issue seriously and it found three independent experts and Dr. Budnitz queried if this is not perceived as having taken the issue seriously what would be? Dr. Budnitz asked Ms. Seeley and the other members of the public to give the Committee the benefit of the doubt that it is taking the matter seriously.

Dr. Meshkati thanked the SRT for an excellent review and presentation and he thanked the public for their comments. He confirmed that the Committee has taken this very important issue seriously as Dr. Peter Bird is a very distinguished, credible person and he has a lot of respect for San Luis Obispo Mothers for Peace and the other groups. He commented that the SRT consists of nationally recognized experts and they have reviewed Dr. Bird's filings with the Committee, Dr. Bird's filings with the NRC, and the PG&E 2015 and 2024 SSC reports. Dr. Meshkati stated one should de-couple the review of Dr. Bird's Critique in the SRT's Report and its conclusions which are based on the best available science that Dr. Bird's critiques can be tabled. But, Dr. Meshkati stated there is another point to the SRT's review which he remarked is a beautiful unintended consequence of the SRT's Report and that is the recommendations for PG&E and he stated he salutes PG&E for being open minded and for listening.

Dr. Meshkati then posed a question to PG&E on whether PG&E accepted SRT's nine recommendations. Dr. Madugo replied that PG&E has not yet done so and would review the nine recommendations, first checking to see if they are technically defensible and then to perform sensitivity studies to assess the potential impact on the seismic hazard. He remarked that this is why he gave the example of the Southwest Boundary Zone which the SRT believes is the model that should be assigned the most weight, with the Los Osos model assigned the lowest weight and he remarked in terms of sensitivity this weighting has already been done and accepting one model over the other does not have an impact on the hazard. He observed this has implications and the San Luis Obispo Mothers for Peace and the other intervenors maintain that the seismic hazard and risk is so high that the plant needs to be closed immediately. He observed that the SRT has made several recommendations and he gave as an example the impact on hazard and risk to the plant of choosing just one model and again commented this would not significantly impact the hazard and the plant would not be shut down as a result. He remarked it then becomes a question of whether the modeling is correct, the dip is correct, and when one incorporates that into a new model. He stated there remains a question as to when an update would be performed. Dr. Madugo commented PG&E is evaluating all these issues and is considering all of the SRT recommendations very seriously and he underscored the point that PG&E was already working on research that supports work that the SRT recommends before receiving those recommendations. Dr. Madugo confirmed that PG&E has not yet accepted the SRT's recommendations.

In responding to Dr. Meshkati's query concerning a statement made during Dr. Madugo's presentation concerning the evaluation of hazard sensitivities in order to assess the hazard significance, Dr. Madugo gave the example of source models weighing different parameters and addressing uncertainties through PG&E's process which requires trying to capture the mean hazard's center, body and range and he stated there could be different models that could also be correct and therefore the models are weighted. He described the term sensitivity as referring to weighting parameters or models at 100%, which is to say one is 100% certain that that model or parameter is correct and then seeing what impact that has on the hazard. Dr. Madugo commented that this is a standard process when one is evaluating new data. Dr. Meshkati observed and Dr. Madugo agreed that this represents the sensitivity study recommended by SRT Recommendation No. 9 and Dr. Madugo stated to that extent PG&E has accepted Recommendation No. 9 and is already responding to it.

Dr. Peterson observed that the SRT's report did not evaluate the hazard, as that was completely out of the scope of their assignment which was to review the documents and associated materials that make up the Bird Critique. Therefore, it is important for the Committee to understand the sensitivity question of how these arguments would affect the assessment of the hazard to the plant, which ultimately is what the Committee should care about in terms of decisions around safety.

Dr. Budnitz stated he was speaking personally and not for the Committee and as he has stated during prior meetings, if Dr. Bird's entire body of analyses and interpretations is given 100% weight and in fact the size and recurrence for the seismic feature that Dr. Bird claims is beneath the plant is correct, then the plant is not safe enough for him. He commented that the sensitivity analysis that was spoken of previously is in the same vein, if certain features are established then one can explore their implications and make the decision on importance.

Dr. Madugo remarked he wanted to draw attention to the contrast in Dr. Bird's statement that there are a number of points of agreement between him and the SRT, with the principal contentions made by Dr. Bird that potentially would increase the hazard as well as the risk to the plant. He commented he believes the SRT has discounted all of Dr. Bird's principal contentions.

Ms. Jan Boudart was recognized. Ms. Boudart stated she had been attending this meeting as well as another meeting and she is the secretary of a nuclear energy information service. She stated she does not understand the relationship between coupons and embrittlement and she commented embrittlement does not seem to be a factor in determining whether these power plants should continue for twenty or forty more years. She remarked she understood almost nothing of the seismic analysis.

Dr. Peterson stated the Committee will return to this discussion during the morning session, including concerning the Committee's potential resolution related to the recommendations provided by the SRT's Report.

In response to Dr. Kadak's comment about the discussion of a fault being under the plant, Dr. Madugo replied if one accepts the Southwest Boundary Zone model as constructed by PG&E, the model has a fault essentially directly beneath the plant. The Southwest Boundary Zone is directly offshore, within the near field and he observed this is not new information. Dr. Jordan remarked that Dr. Bird's assertion that the plant would not survive a seismic event on this fault is a very different statement than the statement that there is a thrust fault beneath the plant and the SRT agrees that there is an active thrust fault beneath the plant. But Dr. Jordan stated the questions are what is its capability, what is its recurrence interval for an earthquake, and how large an earthquake can it produce? Dr. Jordan stated the SRT has not done that assessment. Mr. Rathie observed doing so was not part of the Committee's charge to the SRT.

Mr. Rathie then thanked all three of the members of the SRT, Drs. Jordan, Mashall and Oskin, and stated it has been a pleasure to work with each of these gentlemen.

XVII   ADJOURN EVENING MEETING

            The Chair adjourned the evening session of the DCISC at 7:18 p.m.

XVIII  RECONVENE FOR MORNING MEETING

            The morning meeting of the DCISC was convened by the Chair, Dr. Peterson at 9:00 a.m. and Dr. Peterson welcomed those present in the meeting room and attending online through the Zoom webinar livestream feed.

XIX     COMMITTEE MEMBER COMMENTS

            There were no comments by the member at this time.

XX      DISCUSSION, DIRECTION AND ACTION AS APPROPRIATE, BY THE COMMITTEE, CONSULTANTS & COUNSEL (Cont'd.)

                        Mr. Rathie reported that the protocols he reviewed earlier at the beginning of the first session of this public meeting would continue to guide the public in addressing comments to the Committee.

Further Discussion of Future DCISC Actions, Initiatives, or Recommendations Based on the Results of the DCISC's Review by Drs. Jordan, Oskin and Marshall of Dr. Peter Bird's Concerns Regarding the Seismic Hazard for DCPP.

            Dr. Peterson reported that a Resolution has been drafted to address the SRT's work and the recommendations stemming from its Report and he asked Mr. Rathie to review the operative provisions of that Resolution. Mr. Rathie reported those provisions include: (1) conveying the recognition, appreciation and commendation of the Committee to the three members of the SRT; (2) accepting the SRT Report on the Bird Critique into the records of the Committee and endorsing the Report, its conclusions and recommendations and including the Report in the Committee's 35^th Annual Report; and (3) adopting the nine recommendations made in the SRT's Report as the Committee recommendations to PG&E in the 35^th Annual Report. Mr. Rathie observed this meeting is the final meeting within this annual report period, that is, from July 1, 2024 through June 30, 2025.

            Dr. Budnitz observed this is the first occasion on which the three DCISC Members have had an opportunity to have a discussion amongst themselves on the SRT's report and he remarked he was not yet ready to endorse the report until he has the opportunity to hear from Dr. Peterson and Dr. Meshkati and from the public. He remarked there are two issues arising from the report, the SRT's response to Dr. Bird's critique and the recommendations made in the report. He observed if adopted by the DCISC the recommendations state what the Committee believes PG&E and more broadly the seismological community ought to do and how that fits into the understanding of DCPP seismic safety. Dr. Peterson agreed that the Committee's decision on the SRT's recommendations was the most substantive discussion before the Committee this morning. Consultant McWhorter remarked that the intent of making recommendations to PG&E is to initiate a discussion with PG&E with the acknowledgement that there might be new information in that context that would modify the Committee's recommendations in the future.

            Dr. Peterson stated and Dr. Meshkati agreed that Recommendation No. 9 is an over-arching recommendation, in that it provides for further work to address the other recommendations by performing sensitivity studies to determine whether or not the specifics of the other recommendations would have a significant impact on the seismic hazard. If that impact is small, then one should still follow through with the further work on the other recommendations, but possibly with a less intensive effort. Dr. Budnitz stated that it is his understanding PG&E is receptive to doing or having done the further work as a result of addressing Recommendation No. 9.

Dr. Meshkati briefly reviewed the steps taken to identify the experts who serve on the SRT, the Committee's receipt and review of their Report subject to the restrictions if the Bagley-Keene Open Meeting Act, and the process for the comments provided to and considered by the SRT. He reported that the final report was made available to Dr. Bird and to the public prior to this meeting and Dr. Meshkati stated his position is that deference is due to expertise of the SRT. Dr. Budnitz stated that in his review he found each of the eight recommendations preceding Recommendation No. 9 to be fully technically supported by the SRT's Report.

            Dr. Gene Nelson of Californians for Green Nuclear Power was recognized. Dr. Nelson displayed a USGS map from 2016 which he stated shows the seismic shaking potential throughout California and he reported Dr. Bird is credited as a contributor to this map. He remarked the location of DCPP is not indicated as an area which would be expected to experience the highest level of seismic hazard. He commented San Luis Obispo provides an opportunity as a geological laboratory. In the area of Wallace Creek one can view what Dr. Nelson described as the world's best preserved example of lateral strike-slip faulting causing a stream offset which he stated helps to understand plate tectonics, as this offset was likely caused by an atmospheric river event approximately 3,900 years ago and since that time the Pacific Plate has moved northwest about 420 feet. He reported the 1857 Fort Tejon earthquake, where the Pacific Plate side moved at least 15 feet, occurred slightly north of Wallace Creek and propagated south to Fort Tejon. Dr. Nelson observed the action in California is along the San Andreas Fault and not in the Irish Hills. He stated Californians for Green Nuclear Power believe Dr. Bird systematically biased his recent claims regarding DCPP. He stated on behalf of Californians for Green Nuclear Power he has sent letters to the NRC, copied to Dr. Bird, and to the California Seismic Commission and received no response from either. Dr. Nelson displayed a map he stated was created by the Japan Meteorological Agency that showed earthquake activity on the Noto Peninsula since 2000 and he compared that activity to the Irish Hills local seismic environment where there has been one large earthquake near San Simeon, a magnitude 6.3 event in 2003. Dr. Nelson remarked that while opponents want to follow an emotional narrative that would put that earthquake directly beneath the plant there is no physics to support that. He observed for regulatory significance the period to understand is the Holocene Epoch which began about 11,000 years ago and he characterized this as ancient history and stated we need to be looking at what is happening at the present time.

            Mr. John Geesman representing the Alliance for Nuclear Responsibility was recognized. Mr. Geesman requested that the Committee include with the Southwest Boundary Zone portion of Recommendation No. 9 an insistence that PG&E respond to a recommendation made in 2008 by the California Energy Commission, endorsed by the CPUC, to include review of a San Simeon-type earthquake directly beneath the plant. Mr. Geesman stated he disagrees with PG&E's claim that this has been done and he asked the Committee to request documentation and Mr. Geesman commented as he is not a seismologist he cannot know the likelihood of that thrust fault posing a hazard. Mr. Geesman reported when his client entered into the Joint Proposal, as a condition of that entry his client withdrew its recommendations and expunged its testimony from the evidentiary record and that has been done, however, the requirement to review the impact of a San Simeon earthquake directly beneath the plant remains. Mr. Geesman stated while he realizes the Committee cannot force PG&E to do anything, it can demand information and he asked that the Committee include the issue he identified within the Southwest Boundary Zone portion of Recommendation No. 9.

            Dr. Madugo was recognized and he stated that the PG&E model considers three different thrust faults beneath the plant, the San Luis Bay Fault, which is within the Southwest Boundary Zone, the Los Osos Fault, and the Background Model Fault and he stated those faults have already been considered and past reports have included deterministic analyses considering the San Luis Bay Fault and for that reason PG&E believes the matter raised by Mr. Geesman concerning the California Energy Commission's recommendation has been completed.

            Dr. Madugo observed the SRT Report was looking primarily at source characterization in the models, but to do risk analysis one needs to do source and ground motion characterizations and then one needs to evaluate the hazard and evaluate the risk and the SRT has stated they did not do hazard evaluation as part of their Report. Dr. Madugo stated some things regarding the hazard in terms of the contentions raised by Dr. Bird can be inferred from the SRT's Report, but the SRT recused themselves from the risk portion of Dr. Bird's analyses and he remarked the charge of the DCISC is to evaluate the potential risk to and safety of the plant and he stated he does not know if the DCISC has any comments on the risk portion of Dr. Bird's analyses.

            Ms. Linda Seeley, a member of San Luis Obispo Mothers for Peace, was recognized. Ms. Seeley queried concerning the earthquake fault that runs directly under the plant why the SRT was not charged with analyzing that fault and she stated this was of great concern to her as she has lived six miles from the plant for over forty years. She stated she was also curious as to why the Committee is not focused on the issue from 2008 raised by Mr. Geesman. She stated in response to Dr. Nelson's comments that the Tohuku Earthquake that caused the terrible damage to the Fukushima Dai-ichi Nuclear Plant in Japan had an epicenter 50 miles from Fukushima and just because the epicenter might not be directly at DCPP, if there were a large earthquake that would be of great concern to her.

            Ms. Jan Boudart was recognized. Ms. Boudart stated the first thing Dr. Bird did was to defend his analogy regarding the Noto Peninsula earthquake and she stated she would like to see that analogy analyzed further to determine whether Dr. Bird's opinion is correct.

            Ms. Peg Frerking was recognized. She stated she found the discussion to be illuminating and she inquired regarding what size earthquake DCPP was designed to withstand and if its resiliency to earthquakes has degraded over time. Dr. Budnitz responded and he stated different parts of the plant were designed to different earthquake loads because they were designed at different times, but after the discovery of the Hosgri Fault everything that came later was designed to the Hosgri Fault spectrum based on the level of energy at differing Hertz levels.[26] He reported testing equipment uses the Hosgri Fault as the seismic basis for later designs, but for earlier installed equipment the NRC required a subsequent evaluation to ensure sufficient strength to withstand seismic events. Dr. Budnitz reported that accordingly every safety system in the plant has either been designed to or carefully reviewed to ensure it can withstand an event at the Hosgri Earthquake standard. By the use of the term withstand, Dr. Budnitz stated he means a component must be completely elastic during and after a design-basis earthquake. He reported that after the Hosgi Earthquake standard was approved, NRC guidance was issued to require an analysis be done for larger earthquakes, including for 20% and 50% and larger events.

            Dr. Budnitz stated in response to Dr. Madugo's comment that, although there are some uncertainties it is known at what point different items will fail to perform their functions and that core damage frequency was a part of the analysis done by the Seismic Probabilistic Risk Assessment which has been peer reviewed by experts and it is known at what point a very much larger earthquake causes enough damage to bring about an accident. Dr. Budnitz remarked there is some uncertainty which is accounted for, and he reported DCPP does not get into trouble unless an earthquake about twice as large as the design basis were to occur. The likelihood based on annual frequency of such an event is for the seismological community to determine and that assessment was done as part of the 2015 Seismic Source Characterization and it is not true that it is not known at what point in the event of a very large earthquake the plant gets into trouble. Dr. Budnitz observed if Dr. Bird is right and the earthquake his analysis puts under the station were to occur, then the plant would be in trouble, but the SRT Report has determined that Dr. Bird's hypothesis does not stand up to the best science.

            Dr. Budnitz commented regarding the fault under the plant referred to by Ms. Seeley that this fault has been assessed and has been analyzed and determined to be too small to cause trouble to any DCPP structures or equipment and this analysis has been reviewed and concurred with on multiple occasions.    

            Concerning the resolution before the Committee regarding the SRT's Report, Dr. Peterson observed the recommendations in the resolution should be modified to include the latest version of the nine recommendations as they were displayed on viewgraphs used by the SRT at this meeting.

Dr. Meshkati stated the issues raised about core damage frequency were not addressed in the SRT Report and that the SRT's Report concerns seismic source characterization. He then posed a question about uncertainty and the issue of expert panel judgment. Dr. Meshkati asked about the issue of peer review in context of the SSHAC process and he stated he wanted the record to reflect that the Committee is not discussing core damage frequency and the SRT report concerns seismic source characterization. Dr. Meshkati asked Dr. Jordan for his view on uncertainty in context of expert panel judgment of time dependent earthquake rupture. Dr. Jordan responded there are two types of uncertainty; one being aleatory uncertainty, which is associated with the fact that nature has an element of randomness, and the second being epistemic uncertainty which is associated with a lack of knowledge about how the earth behaves. He reported nothing can be done about aleatory uncertainty, but epistemic uncertainty can be addressed by further study and he stated this is one of the principal points of the SRT's Report and the main point of its recommendations. Dr. Meshkati commented on the importance of independent peer review in the SSHAC process and he asked Dr. Jordan if he agreed with the statement made about the seismic source characterization in the PG&E reports of 2015 and 2023 and he inquired regarding the SRT's recommendation. Dr. Jordan stated all the recommendations in the SRT Report are directed at reducing the epistemic uncertainty.

            Dr. Budnitz observed that work on the Recommendation No. 9 made in the SRT's Report may lead to a finding regarding the sensitivity of the various recommendations to the overall hazard, and there are some items for PG&E to perform and PG&E should then inform the DCISC and the IPRP of the results. He remarked that some of the SRT's recommendations are directed to PG&E and others are directed to the acquisition of information without a delegation regarding who should perform the work and he observed there are many experts unrelated to PG&E who will be reviewing the responses to the recommendations made in the SRT's Report.

            On a motion made by Dr. Peterson, seconded by Dr. Meshkati, the DCISC Members unanimously adopted the Resolution as described previously by Mr. Rathie and the nine recommendations contained in the SRT Report with the caveat that the recommendations be verbatim the SRT's most current version. [The latest version of the nine recommendations was included in the foregoing.]

Mr. Rathie commented that in accordance with the direction in the Resolution, the nine recommendations will subsequently be incorporated into the Committee's 35^th Annual Report and adopted as recommendations of the Committee to PG&E, and PG&E upon receipt of the Annual Report will respond in writing to each recommendation. Dr. Budnitz observed that after the work to address the Committee's recommendations is completed there will be some new insights among which could be that the seismic hazard at DCPP has not changed very much, or if what is learned modifies the seismic hazard then the next action is to ask the question what is the implication on the understanding of the safety of the plant? He recommended the Committee follow this in context of the broader picture and if important changes based on the best science are identified then the implications for overall seismic safety needs to be determined on a high priority basis. Dr. Peterson thanked everyone for the very helpful input and discussion over the Committee's consideration of this matter.

            Following adoption of the Resolution the Members discussed with Dr. Jordan responding to the communication rebutting the SRT Report received from Dr. Bird on June 6. 2025. Dr. Jordan confirmed the SRT is prepared to respond to Dr. Bird's rebuttal and the Committee then requested and directed the SRT to develop this response.

H.        Review of Open Items List and Status of Recommendations.

            Dr. Peterson requested that Consultant Wardell lead a review of items on the Open Items List, which he described as an important tool used by the Committee to set priorities, track, and to follow up on issues, concerns, information requests and activities identified for subsequent action or receipt during fact-finding or public meetings. Mr. Wardell stated he appreciated Consultant McWhorter's assistance with the Open Items List and he reported newly added or changed items were shown in red italics while items for which follow up is scheduled prior to the June 2024 public meeting were shown in yellow, and items which were deleted or changed were shown in strike-out on the version of the Open Items List included with the agenda packet and certain items on the list were identified for closure.

Items discussed or concerning which action was taken included the following:

Open Items List[27]

Item	Re:	Action Taken/Next Action
CO-10	Review Storm Response Experience/Strategy	Mid-2026
EN-19	Review Major Engineering Programs	8/25FF
EN-20	Each Member Observe a Plant Health Committee Mtg.	8/25FF-NM
HP-25	Review Management Observation Program	2Q26FF
PI-3	Review AI Applications	7/25FF
MS-5	Monitor NSOC Meetings	6/26/25 & 8/25FF-NM
NS-11	Meet Periodically with SNO Member Representatives	6/17/25 & TBD
RP-12	Review Annual Radioactivity Release Reports	7 or 8/25FF
QP-9	Software QA Program	8/25FF
SE-49	Review EDGs	9/25FF
SE-50	Maintenance Rule Functional Failures	7/25 or 4Q25FF
SEC-3	Operations -Security Interface	Mid 2026
SF-2	Holtec Casks, SFP Storage, ISFSI Relicensing	4Q25
SC-14	Monitor Work of IPRP	Next IPRP Mtg.RJB
SC-15 (New)	Review Significant Seismic Events as the Occur	TBD
SC-16 (New)	LTSP Response to SRT/DCISC Recommendations	TBD
SC-17 (New)	Follow SRT Progress re Dr. Bird Critique	Close EO-10
LD-6	Review Non-Licensed Ops & Training	8/25FF
NR-5	NRC DPO Program & OIG Reports relative to DCPP	TBD
NR-6	Review Impact of Presidential Executive Orders re NRC	TBD
EO-3	Monitor State/Local Permitting	Prior to 2/26PM If Activity
EO-4	Monitor NRC License Renewal Application	Prior to 2/26PM If Activity
EO-10	Follow SRT Progress re Dr. Bird Critique	Close Under EO - Open SC Item/SC-17
O-3	Review Studies/Reviews of Drone Activity at DCPP & Presidential Executive Orders	8/25FF or 4Q25
O-4	Station Update at Each FF	7 & 8/25FFs 10/25PM
10/24PM-9	Review ALARA Numbers	Close
2/25PM-1	Report on PG&E Plant Tours & Community Engagement	Close
2/25PM-5	Process Map re Notification	Close
2/25PM-6	FF Reports Include Updates of Prior Recommendations	Close
2;/25PM-7	Review Use of Electronic Procedures	7/25FF Then Close
2/25PM-11	Operator Training on EDMGs	8/25FF
2/25PM-19	Common Cause Evaluations (spelling of Lalone)	Close
2/25PM-21	Capitalize "Process Safety Management"	No Change
Recommendations to DCISC
D12/24FF-3.4	Artificial Intelligence and List	7/25FF
D1/25FF-3.9A	Safety Culture	9/25FF
D1/25FF-3.9B	Number of Anonymous Notifications	10/25PM
D3/25FF-3.12	DCISC Emergency Response Policy	10/25PM
Recommendations to PG&E
P12/24FF-3.2	Expanded Use of Electronic Procedure Applications	7/25FF-PFP
P4/25FF-3.6	FLEX Guidelines for ASW System Alternative Discharge Path	9/25FF
P6/25PM	SRT/DCISC Nine Recommendations	10/25PM 35th A/R
DCPP Systems Review
230kV & 500kV- Grid Inertia-Transmission Interference		9/25FF
Auxiliary Building Ventilation		7/25FF
DCPP Programs - Periodic Review
Boric Acid Corrosion Control		2025
Spent Fuel Management		2029-2030
Cask Inspection		9/25 & TBD
Vibration Monitoring		7/25FF

            A short break followed.                      

XXI     INFORMATION ITEM PRESENTED BY THE NRC SENIOR RESIDENT INSPECTOR FOR DIABLO CNYON POWER PLANT

            The Chair requested Consultant McWhorter to introduce the NRC Senior Resident Inspector for DCPP Mr. Mahdi Hayes. Mr. McWhorter welcomed Mr. Hayes to these proceedings and he reported Mr. Hayes is a graduate of Texas A & M University and holds a Bachelor of Science Degree in Nuclear Engineering. He stated Mr. Hayes previously worked for Knolls Atomic Power Laboratory prior to joining the NRC in 2006, after which Mr. Hayes served as the Resident Inspector at the Columbia Nuclear Generating Station in Washington and then as an Operations Engineer and Operations Licensing Examiner in the NRC's Region IV offices in Arlington, Texas, after which in 2022 he was assigned as the Senior Resident Inspector for DCPP. Mr. McWhorter reported that today Mr. Hayes is accompanied by Mr. Jeffrey Miller, Division Director for Reactor Safety for NRC Region IV, and by Mr. Jose Cuadrado from the NRC Office of Congressional Relations at NRC Headquarters in Rockville, Maryland, and by Mr. Cuadrado's Administrative Assistant Ms. Amy Alon.

            Mr. Hayes reviewed the mission statement for the NRC as follows "The NRC protects public health and safety and advances the nation's common defense and security by enabling the safe and secure use and deployment of civilian nuclear energy technologies and radioactive materials through efficient and reliable licensing, oversight, and regulations for the benefit of society and the environment." He reported this is a change from the previous mission statement and his presentation would focus on the efficiency element of the mission statement. He reported the agency's strategic goals cover a four-year plan and include, for safety and security providing quality oversight in nuclear facilities, for radioactive materials, and for stakeholder confidence to engage stakeholders in NRC activities in an effective and transparent manner. He stated the NRC's overall assessment of DCPP's operation was the plant operated safely and preserved public health and safety and both DCPP units were in the Licensee Response Column of the Reactor Oversight Process Action Matrix with all Green findings and all Green Performance Indicators. During 2024 approximately 7,500 hours of inspection activity were conducted including multiple License Renewal, Aging Management, and Problem Identification and Resolution inspections. There were 11 Severity Level IV findings, including 8 stemming from the review activities of the Resident Inspector Team. He discussed each as follows:

→        Failure to Maintain Annunciator Response Procedure: Mr. Hayes reported this finding relates to DCPP's failure to update its annunciator response procedures with information from the Technical Specification (tech specs)[28] bases. DCPP has what he termed 'permissives' in its tech specs, including for condenser availability. If the condenser, which takes in steam, is not available in a plant trip situation the steam goes out into the atmosphere instead of into the condenser. DCPP made a change some time ago to include a requirement to have the condenser available at all times to support the safety analysis. During the rainy season in the December/January timeframe, DCPP had a design deficiency that allowed water to back up into a sensing line that could take the sensing line and the condenser out of service. Mr. Hayes reported DCPP correctly entered into a tech spec action but had previously failed to review information in the tech spec bases and to incorporate that information into the annunciator response procedure or any other type of procedure. Dr. Peterson commented and Mr. Hayes agreed the safety significance of this issue is due to the use of the condenser as a heat sink for a reactor trip. Mr. Hayes observed the condenser was not relied upon as a heat sink in the original licensing for DCPP. He commented under the prior tech specs DCPP would have to experience a mandatory trip above ten percent power and in order to avoid what DCPP deemed unnecessary trips that tech spec limit was subsequently raised to be above fifty percent power, but in order to meet that revised tech spec the plant needs the condenser steam dumps to be available and with that change the condenser became more important and part of tech specs and DCPP had failed to recognize that fact for a number of years.

Dr. Peterson commented that is one of the reasons the plant will reduce operating power during winter storms which involve the risk of kelp being broken up and then pulled into the circulating water intake and causing a trip of circulating water pumps and a reactor trip and he observed the condenser steam dumps are not going to work very well because that scenario is a pretty severe transient.

In response to Dr. Budnitz question as to whether there was any operating experience of other plants on this condenser steam dump system maintenance issue Mr. Hayes responded that a number of plants have changed their schemes to add in the permissives, but in his research he found none that had experienced this same issue. He stated the reason it was dispositioned as Green, or of low safety significance, was because there are other ways to reject heat on a plant trip, but he stated it is important that the site knows what is in its licensing basis and follows that licensing basis at all times.

In response to Dr. Meshkati's questions Mr. Hayes confirmed the annunciator is located in the Control Room, within the middle section of the control panel above the steam generator and feed pump areas, and there is an alarm window that usually indicates the condenser is available and when that alarm window went dark during a storm event the plant knew that the condenser was unavailable and when the annunciator response procedure was reviewed it lacked the information to review the tech specs. Mr. Hayes confirmed there was no human factor aspect to this event as everything worked exactly as it should have and the indicator was there and it went dark. The operators complied with the annunciator response procedure correctly, but the procedure did not have the needed information.

→        Inadequate Maintenance Rule Evaluations on Condenser Steam Dump System: Mr. Hayes reported this issue arose because of the discovery of a failure to do Maintenance Rule evaluations. As part of a plant's license the NRC has what is termed the Maintenance Rule, 10 CFR 50.65, which provides the regime for managing the availability and reliability of important systems and equipment for not only safety but overall operation. He reported DCPP had all the requisite systems properly scoped, but as part of that scoping effort the plant failed to recognize that some systems affect multiple areas. When the condenser pressure transmitter went out of service DCPP reviewed that failure against one particular plant system, but plant staff did not review how that failure could affect other plant systems. This was true for the condenser steam dumps, a system that was scoped in the Maintenance Rule, and when that system was no longer available for use this created a maintenance preventable functional failure, because the sensing line was something that could have been fixed, but a decision was made some years prior not to do so. The NRC review looked at all supporting systems, not just one, and it was found the count of systems reviewed was incorrect.

→        Failure to Remove Valve Parts Resulting in Reactor Trip at Low Power: Mr. Hayes reported when entering an outage during 2023, there was a plant trip at eleven percent power due to a feedwater heater backing up with water in the controllers and therefore the dumps and the drain controllers were not working properly and a plant trip ensued as procedure directed. When the valve was disassembled to investigate the issue, it was found that the valve had extra parts installed that should not have been present. The valve was rebuilt in the 1990s and according to the vendor's instructions those valve parts, a spring and another component. should not have been present when the valve was rebuilt. The vendor instructions were not followed and over time there was some binding of the valve and eventually it would not open correctly. This led to water backing up in the feedwater heater and to the plant trip. In response to Consultant Kadak's query Mr. Hayes confirmed the valve was rebuilt by the plant.

→        Failure to Consider Appropriate Performance Criteria for Maintenance Rule Components: Mr. Hayes reported this issue dealt with roofs and drains. As part of Diablo's design for the Auxiliary Building roof, which houses radiological controlled areas and safety-related systems, and also the Fuel Handling Building roof, there are drains and scuppers used to divert water from the roofs to prevent too much loading and the roof collapsing. As part of original scoping of those components in these buildings, the plant made the decision that a collapse of the roof would constitute failure of the component. Mr. Hayes stated during the NRC Inspection Team's walk-downs of the site during the rainy season to look for ponding on roofs, ponding was observed and drains and scuppers were found clogged. The NRC inspectors assessed this situation under the Maintenance Rule and found the underlying criteria questionable. Mr. Hayes observed the failure of a building should not be the criterion for a maintenance prevention functional failure and the decision was reached that failure of a roof was too high a criterion and a lower level failure criterion would better contribute to a good maintenance program to clean out the drains, clean up the scuppers, assure adequacy of the design, and ensure the drains are sized correctly. Appropriate actions were taken and inspections were completed for the buildings and the roofs to ensure that the revised maintenance criterion is followed. In response to Dr. Meshkati's query as to whether this issue was somehow related to the management of change Mr. Hayes replied that was a difficult question because the buildings were re-roofed in the 1990s and processes and programs were not as robust then as they are now. In response to Dr. Meshkati's question as to how this could have been prevented Mr. Hayes responded it could have been prevented by incorporating engineering into the process of change when doing maintenance or a re-roofing.

→        Failure to Maintain Original Design after Maintenance: Mr. Hayes stated over the years DCPP re-roofed both the Auxiliary and Fuel Handling Buildings and the size of the scuppers was left unchanged without doing proper engineering evaluation to determine that a new size would move the amount of water that needed to be moved in a maximum rainfall event.

→        Failure to Make an Interim Part 21 Report: Mr. Hayes reported under 10 CFR Part 21 if there is an expected substantial safety hazard from a component, this needs to be reported to the NRC. In this case DCPP experienced a series of pipes snubbers failing to release and only moving in one direction. The pipes snubbers are supposed to move in two directions, to move in compression and tension, and they were locking up in the tension direction. When the snubbers were removed and examined they were found to have been over-greased which was associated with worker practices at the factory. Accordingly, this was found to be a significant problem and the affected radioactive components were shipped offsite which was coordinated with the vendor. Since the plant believed that there could be a potential issue of a substantial safety hazard, it fell under the requirement to report the problem to the NRC within sixty days, with the caveat that if for some reason it cannot be reported within sixty days because the evaluation is not complete, an interim report needs to be made concerning the evaluation. Mr. Hayes reported DCPP missed submitting that interim report. He stated DCPP recognized the issue and its severity and was working to get the interim report completed, but they failed to do so.

→        Failure to Correctly Determine Operability of Auxiliary Building Ventilation Fan: Mr. Hayes reported that during the period that DCPP had a diesel generator out of service, an Auxiliary Building ventilation fan had failed due to thermal overload and was not available for that diesel. Mr. Hayes reported that when this happens the plant has to do a cross-division check to ensure that there are minimum systems to support the license and ensure safety. Because the Auxiliary Building ventilation fan failed, the plant was required to initiate an action statement for a period that was much briefer than the one that they were then in. DCPP had maintenance requirements that allowed the Maintenance organization to reset relays, particularly thermal overloads on 480-volt components, and then to run the system again to see if it will trip again. Mr. Hayes reported the plant does that with smaller components, such as relays serving the laundry and other items that have nothing to do with safety. The shift manager and the senior reactor operators at the time got that requirement confused with the direction in the tech specs. He stated the tech specs are very clear that a component must be able to perform its safety function and when you have a thermal overload trip, that thermal overload prevents you from restarting the component. It was clearly inoperable at the time and the senior reactor operators were confusing multiple procedures and accordingly they missed the time requirement. Mr. Hayes observed this was also a condition that led to a notification of enforcement discretion for the timing of shutdown. The NRC inspection team clearly communicated with the plant that this situation was an incorrect application of an operability assessment regarding the building's operability.

→        Failure to Preclude Repetition of a Bearing Failure of Auxiliary Saltwater Pump 2-2: Mr. Hayes reported for some time the auxiliary saltwater pump motors have been an issue. This involved an issue with bearing motor oil having particulates which is usually caused by the bearing rubbing. When the particulates were discovered the plant increased the monitoring plan and flushed the system which Mr. Hayes remarked were the correct steps, and subsequently analysis did not indicate the presence of particulates. DCPP then changed the timeframe for taking samples, but in the next sample particulates were again found and the plant then shortened the sampling schedule time. Mr. Hayes reported, however, the direction to do so did not get communicated to the right person and instead was sent to a work planner who was at that time on vacation and when the planner returned he or she had to look through a great number of emails and missed this email communication about the change in the sampling schedule. The NRC resident inspection team found the Notification with the information regarding increasing the sampling timing and determined the last sampling was outside of the recommended timeframe. A cause evaluation was completed and the NRC resident team decided to turn the issue over to the NRC's Problem Identification and Resolution inspection team because it was believed the team was in the best position to investigate and deal with this issue. Mr. Hayes stated the Problem Identification and Resolution inspection team reviewed the cause evaluation and the Auxiliary Saltwater System and determined that the plant had a corrective action to prevent recurrence that that saltwater pump should never fail in that manner again, but it did. The Resident Inspection and the Problem Identification and Resolution inspection teams determined this issue was related to the setting of the tolerance between pump and motor due to inadequate maintenance instructions with respect to setting the required gap distance between the pump and the motor. In response to Consultant Kadak's question Mr. Hayes stated DCPP had the settings right and the numbers correct but failed to train the Maintenance personnel correctly to make the settings and it required an engineer watching the work to identify the incorrect instructions.

Mr. Hayes reported during 2024 DCPP was in Green status for all findings and indicators. He stated concerning industry-wide performance, 85 plants were in the Green Licensee Response Column of the Action Matrix while 9 were in the White Regulatory Response Column and none were in columns with higher regulatory involvement. He further reported 546 Green findings were written industry-wide in 2024 with one Greater-than-Green and four White violations with no Yellow or Red violations having been written in 2024. For the remainder of 2025 Mr. Hayes reported the NRC plans to conduct the Baseline Inspection Program as well as the Triennial Fire Protection and Cyber Security inspections at DCPP.

Concluding his presentation, Mr. Hayes provided information to the public on how to contact the NRC by telephone, internet, and social media and he stated there were feedback forms to provide written comments in the meeting room.

In response to Dr. Peterson's question concerning the recent Presidential Executive Orders directed to the NRC, and any consequences identified to date as a result of their implementation, Mr. Hayes stated the Resident Inspection Team will continue to fulfill its responsibilities on a daily basis and there are no changes for the NRC resident inspectors. Dr. Meshkati commended Mr. Hayes' attention to an article by Dr. Edwin Lyman of the Union of Concern Scientists with what he stated was an interesting analysis of the Green inspection designations by the different NRC regions and which identified 13 nuclear power plants as poor performers. Dr. Meshkati reported that DCPP was not on Dr. Lyman's list of poor performing plants.

Mr. Jose Cuadrado from the NRC Office of Congressional Relations at NRC Headquarters in Rockville, Maryland, was recognized. In response to Dr. Kadak's query concerning the effects of the Presidential Executive Orders at NRC Headquarters Mr. Cuadrado stated the NRC leadership team and the Commissioners are reviewing the specifics of the orders and more information will be forthcoming.

Dr. Budnitz observed that the DCISC fact finding teams generally meet with the NRC resident inspectors during each fact finding and he observed, and Mr. Hayes concurred, that if a technical issue emerges and the resident inspectors require assistance there are engineers and support personnel the inspectors can call upon at Region IV and at NRC Headquarters. Mr. Hayes observed he would, in turn, contact the licensee, his supervisor, and then the project manager at NRC Headquarters and a list would be compiled of those persons available to offer technical assistance to the resident inspectors.

Dr. Budnitz observed the NRC Office of Research exists as a statutory office and it is charged with developing information based on requests from the NRC inspectors and inspection teams. Mr. Hayes agreed with Dr. Budnitz and he stated when the project managers at the regions become involved in an issue they would reach out to the Office of Research if necessary. Dr. Budnitz stated that he was once Director of the NRC Office of Research and without that office there would be no resources to provide information, research, analysis, data or methods of analysis to the regions or the inspection teams. Dr. Budnitz remarked that the NRC's ability to do its work at the present time is very strong, but whether that continues depends upon if the Office of Research, which has a central role in the long-term ability of the agency to conduct technical safety review, continues to provide the necessary tools to keep the agency up to date. He commented based on his observation of what he described as the emasculation of the Environmental Protection Agency's Office of Research, he has grave concerns about the long-term efficacy of the NRC Office of Research in the current environment.

In response to Dr. Meshkati's query Mr. Hayes replied to date there is no NRC guidance concerning evaluating, inspecting or monitoring the application of AI as part of the Atomic Canyon project.

Dr. Peterson called for public comment on the morning's presentations or on other topics within the Committee's subject matter jurisdiction not appearing on the agenda.

 XXII  PUBLIC COMMENTS AND COMMUNICATIONS

Ms. Rochelle Becker of the Alliance for Nuclear Responsibility was recognized. Ms. Becker asked with reference to the Green findings, who at DCPP takes ownership for those failures? She remarked PG&E during this meeting has very proudly stated that they take ownership of projects. Mr. Hayes replied that the Resident Inspector team's main interface with DCPP is through its Regulatory Affairs organization as well as with the Director of Risk and Compliance. Dr. Budnitz remarked he could not recall an occasion when the DCISC identified an issue for which there was no project owner associated.

            Dr. Gene Nelson of Californians for Green Nuclear Power was recognized. Dr. Nelson stated he reviewed the article by Dr. Edwin Lyman which referred to the "terrible thirteen" nuclear power plants and that DCPP was not among the plants identified by Dr. Lyman. He commented Dr. Lyman took the sum of all Green findings and then he assigned a weight to White findings by a factor of five to assess a numerical score.

Dr. Peterson observed and Mr. Hayes agreed that an important facet of nuclear safety culture is the ability to find and report things that have low safety significance and he stated in his view a large number of Green findings is evidence that the plant staff is looking closely at fixing things at a low level and accordingly a larger number of self-reported Green findings can be a good thing. He remarked self-identification is a good metric for a healthy safety culture. In response to Dr. Meshkati's inquiry Mr. Hayes replied DCPP does a good job at listening to the Resident Inspection team and acting upon its direction and there has been a mutual understanding reached as to what the plant needs from the inspectors and what the inspectors need from the plant. He remarked the NRC Resident Inspection team is at a point where small discussions can take place to get to the right question and then for the organization to respond and provide the needed answer and he believes the NRC Resident Inspection team and DCPP communicate well.

Dr. Peterson thanked Mr. Hayes and his colleagues for their presentation and stated the DCISC will continue to work closely and meet with the NRC inspectors at each fact finding.  

XXIII  ADJOURN MORNING MEETING           

            The Chair adjourned the morning meeting of the DCISC at Noon.

XXIV  RECONVENE FOR AFTERNOON MEETING

            The afternoon meeting of the DCISC was convened by the Chair at 1:15 p.m.

XXV   COMMITTEE MEMBER COMMENTS

            There were no comments by any member at this time.                      

XXVI  PUBLIC COMMENTS AND COMMUNICATIONS

            Dr. Peterson invited members of the public to address the Committee on matters not on the agenda for this meeting. There was no response to his invitation.

XXVII ACTION ITEMS      

I.          Nomination and Election of DCISC Chair and Vice-Chair for the

            July 1, 2025 - June 30, 2026 Term.

            On a motion made by Dr. Meshkati, seconded by Dr. Budnitz, the Committee re-elected Dr. Peterson to the position of DCISC Chair and then on a motion made by Dr. Budnitz, seconded by Dr. Peterson, Dr. Meshkati was elected to the position of DCISC Vice-Chair, both to serve terms of office from July 1, 2025 through June 30, 2026.

XXVIII INFORMATION ITEMS BEFORE THE COMMITTEE (Cont'd.)

            Dr. Peterson requested Mr. Soenen to introduce the next PG&E presentation. Mr. Soenen then introduced the presentation which was listed earlier on the agenda by the DCPP Director of Risk and Compliance Mr. Jordan Tyman for an update on DCPP regulatory performance. Mr. Soenen reported the Mr. Tyman is responsible for oversight of the nuclear regulatory and compliance program, enterprise and operational risk management, innovation, nuclear cyber security and emergency planning. Ms. Soenen reported that Mr. Tyman has been employed by PG&E for nine years and spent ten years prior to coming to PG&E at Westinghouse Electric Corporation, in support of the development of Westinghouse's AP1000 pressurized water reactor and with a number of Westinghouse's subsidiaries. Mr. Soenen reported that Mr. Tyman has various academic partnerships and holds memberships in numerous industry committees and a Degree in Mechanical Engineering from the University of Massachusetts.

Update on the Status of NRC Performance Indicators, Licensee Event Reports, NRC Inspection Reports and Notices of Violation, Issues Raised by NRC Resident Inspectors, Open Compliance Issues, Status of Cross-Cutting Issues Matrix, Current and Future License Amendment Requests, and Other Significant Regulatory Issues/Requests.

Mr. Tyman stated DCPP learns from its two Resident Inspectors, Mr. Mahdi Hayes and Mr. Eli Garica, who provide valuable insight into daily operation of the plant in addition to the insight gained from regional and baseline inspections to help improve performance. He reported that since the last update he provided to the DCISC in February 2025, the NRC has continued to perform routine inspections through their quarterly inspection process and through baseline inspections which included from 1,700 to 2,000 hours of inspection time reviewing DCPP programs and processes. As a result of the inspections during this period one violation of very low safety significant was received and DCPP continues to remain a top performing plant in the industry with all 16 NRC Performance Indicators in Green status[29] to ensure compliance and that safety systems are meeting regulatory expectations and requirements.

Regarding the Green violation received Mr. Tyman reported it was associated with two examples of workers inconsistently applying standards to work in the field. The first occurred when a security officer used his radio in an exclusion zone where such use can have an impact on other transmitters. The second was work performed on the wrong fire extinguisher system sprinkler head which resulted in a release of water which then sprayed on to the heater drain pump and affected the pump's operation. In response to Dr. Peterson's query he reported both were self-revealing violations. Mr. Tyman reported the station performed extensive corrective actions including multiple stand-downs of the entire workforce on the importance of adhering to standards and procedures and the use of human performance tools. As a response to an earlier public comment, Mr. Tyman stated all plant personnel are considered to be owners of these events. Dr. Peterson observed and Mr. Tyman agreed that use of electronic procedures could have possibly prevented work taking place on the wrong fire suppression sprinkler head as more information would have been available to lower the likelihood of that error.

Mr. Tyman reported there were no Licensee Event Reports issued during the February – June 2025 period and upcoming inspections are scheduled as follows:

Biennial Requalification Inspection – June 1-7

Triennial Fire Protection Inspection - July 6-26

Cyber Security Inspection – August 10-16

Emergency Preparedness Program Inspection – August 25-28

He reported DCPP submitted a License Amendment Request (LAR) for implementation of a change in tech specs to use risk-informed completion times and a separate LAR has been submitted for the instrument and control portion of the tech specs. He reported there are plans to submit additional LARs consistent with industry best practices including revising the E-Plan rebaseline to NUREG-0654 Rev. 2 standards.

            In response to Consultant McWhorter's question Mr. Tyman reported, relative to the license renewal status for DCPP, that a meeting of the Advisory Committee on Reactor Safeguards is planned for July and the Safety Evaluation Report was received recently from the NRC. Mr. Tyman stated he did not have a date for expected approval. He also reported that the Safety Evaluation Report for the ISFSI license renewal has also been received and it is under review by DCPP. In response to Consultant Kadak's query Mr. Tyman reported there are no open or confirmatory items associated with the license application SER.

            In response to Dr. Meshkati's question Mr. Tyman reported he and his organization interact routinely with the NSOC at least three times each year when the Nuclear Safety Oversight Committee (NSOC) is on-site for one week and his organization provides the NSOCand  with updates on plant programs and processes. He reported the NSOC reviews Corrective Action Program documents and conducts interviews and continues to provide good independent insight focused on plant improvement, going above and beyond compliance with regulations. Dr. Meshkati congratulated Mr. Tyman on the effort to go beyond regulations, as Dr. Meshkati stated regulations are typically promulgated based on the least common denominator of the stakeholders. Dr Budnitz observed that the NSOC is appointed by and reports to PG&E management. He reported that the DCISC has been attending the NSOC exit meetings for some time now and the discussion and the feedback at those meetings is intended to be frank and confidential and the DCISC is bound by that restriction in its public reports. Dr. Budnitz remarked the NSOC and DCISC often focus on the same matters and reach similar conclusions. Dr. Peterson remarked that the ability to have access to and to follow the conclusions and recommendations of various oversight bodies is useful to the DCISC. In response to Dr. Meshkati, Mr. Tyman stated he and his organization are not part of the conversations with the PG&E Corporation's Safety and Nuclear Oversight Committee.

XXIX CONSULTANT REPORTS & RECEIVE, APPROVE, AND AUTHORIZE TRANSMITTAL OF FACT FINDING REPORTS TO PG&E          

K.        The Chair requested Consultant Mr. McWhorter to provide a summary report on the April 28-29, 2025, fact-finding visit with Dr. Meshkati. Mr. McWhorter reviewed the topics discussed with PG&E during the April 2025 visit as follows:

→        Outage Management Overview – Consultant McWhorter reported the DCISC fact-finding team (FFT) conducted their visit during day 16 of refueling outage 1R25 for Unit 1 which occupied a total of 35 days. The FFT received a briefing on outage scheduling and management and the status of major activities during 1R25 including the removal of reactor pressure vessel surveillance Capsule B. He reported a briefing was given on the additional scope of work associated with the work on the high-pressure turbine. The FFT concluded 1R25 was being managed well.

→        High-Pressure Turbine Replacement Update and Plant Tour – the FFT toured the plant to observe and receive a briefing on work on the high-pressure turbine internals. Mr. McWhorter reported the internals, consisting of the shaft and turbine blades as one piece and the eight stator rings, will be replaced, but the turbine shell will be retained. Mr. McWhorter reported additional work was identified in connection with the turbine shell sealing surfaces where erosion was found. Mr. McWhorter reported the turbine was known to be near the end of its lifecycle and it was intended to run the turbine to the end of its lifecycle by 2024-2025, but with the decision to extend operations the decision was taken to change the rotating and stator elements. He reported contingency plans were in place as the erosion found was anticipated and the additional work added four or five days to the work to complete the scope. Mr. McWhorter displayed photos of the FFT inspecting the area of the work. The FFT concluded the replacement of the high-pressure turbine was proceeding satisfactorily including implementation of the proactive pre-planning for the contingency plan to address erosion on the sealing of the turbine shell.

→        Observe Outage Maintenance Activity- Consultant McWhorter reported the work observed was removal of a pipe snubber restraint which limits the pipe's motion for seismic events. The snubber was near operable Component Cooling Water Heat Exchanger 1-1 which during shutdown needs to remain in operation to cool safety equipment. Risk mitigation management and rigging plans were in place and protective barriers were put in place and inspected by the FFT and the FFT concluded those plans and actions were appropriate.

→        Cause Evaluation Process – Mr. McWhorter reported this topic was a follow up from the January 2025 fact-finding visit to review recommendations made on that occasion. Mr. McWhorter reported cause evaluations from 2023 and 2024 were provided and reviewed to focus on organizational learning tools and to assess how lessons learned from those tools were incorporated into the corrective actions. The FFT had an open discussion with the plant staff responsible for Correction Action Program and for cause evaluations and some actions for improvement were identified. The FFT concluded the use of organizational learning tools and safety culture assessments was generally effective in capturing and initiating appropriate corrective actions and the recommendation to the Committee from the January fact finding visit was completed and is recommended for closure. The Committee discussed and then agreed that with approval of this Fact Finding Report the recommendation and any action related to the recommendation for closure will be closed and the Open Items List revised accordingly. However, Mr. McWhorter reported there are two new recommendations to PG&E, one of which is new and one that was previously discussed but was not made the subject of a recommendation.

The recommendation that was previously discussed is that PG&E should review its cause evaluation process and initiate actions to ensure that deficiencies observed in the organizational learning tool and safety culture assessment are captured and tied to the initiation of appropriate corrective actions. PG&E has accepted this recommendation and is working to address it and a Notification has been created. Dr. Meshkati commended Mr. Blair Jones, Chief of Staff to the PG&E Chief Nuclear Officer and his colleagues for accepting this recommendation.

The other recommendation, which Mr. McWhorter observed is similar to the other previously discussed recommendation, concerns "periodic trending' which involves reviewing cause evaluations to identify trends in particular areas of organizational learning tools.  

Dr. Peterson remarked that because the Committee has made its recommendations more complex, tracking the recommendations has become more complex.

→        Root Cause Evaluation for Auxiliary Saltwater System (ASW) Pump Motor Failure – this inquiry concerned the failure of an ASW pump motor bearing in 2023 that was a repeat instance of a failure that occurred in 2018. The FFT reviewed the procedure changes put into place and validated in the field and found them to be adequate. The FFT received an update on why the 2018 root cause evaluation was deficient to preclude recurrence, but Mr. McWhorter reported that Notification remains open and a recommendation has been accepted for PG&E to continue to evaluate this issue.

→        Auxiliary Saltwater System (ASW) Discharge Arrangement, Area Tour, and Flex Program – Mr. McWhorter reported at the January 2025 fact finding meeting the FFT reviewed a new tsunami report by PG&E for the California Coastal Commission and during that meeting the FFT asked about the effect of a tsunami on the Discharge Structure in context of FLEX[30]. Mr. McWhorter stated after the January 2025 fact finding a drawing was received that showed the ASW piping located in the concrete Discharge Structure which is under earth and fill. He reported that failure of the Discharge Structure is addressed in the plant's Updated Final Safety Analysis Report (UFSAR) and a collapse of the Discharge Structure is unlikely to clog the ASW discharge outlet piping, but the FFT posed the question as to why there are no FLEX guidelines for loss of ASW discharge due to collapse of the Discharge Structure and PG&E has agreed to review this question. Mr. McWhorter reported the FFT visited the Discharge Structure, which they found clean and well lit, and he used a sketch of a cross-section of the Discharge Structure to illustrate his comments. In response to Consultant Kadak's query Mr. McWhorter stated Dr. Meshkati asked the question which initiated the inquiry and the Discharge Structure is not designed to the same safety standards for seismic events as other areas of the plant. He reported that the FFT did not find this to be a major safety concern, but the issue came up in a programmatic context in terms of FLEX. The FFT concluded that in the event of a possible collapse of the Discharge Structure onto the ASW outlets this scenario should be further reviewed and a determination made as to whether it should be included as part of the FLEX Program guidelines, to provide an alternative discharge path for the ASW following a beyond design basis event that may cause the Discharge Structure to collapse or to otherwise obstruct the ASW discharge flow. Mr. McWhorter reported the recommendation to the Committee from the January 2025 fact finding should accordingly be closed and a recommendation opened to PG&E to review this issue. He reported PG&E has opened a Notification and the matter should be put on the agenda for a fact finding visit this summer.

→        Observe 0730 Senior Leadership Team Outage Briefing – Consultant McWhorter stated the 0730 Leadership Team Outage Briefing reviews the various outage activities and provides management decisions and guidance as needed. The subject matter was the status of the units, safety, any emergent issues, and the status of projects and he reported focused observations are required of the participants. He reported this group also provides backup to the Notification Review Team for outage Notifications initiated within the prior 24-hour period. The FFT concluded that the meeting was conducted efficiently and effectively.

→        Meet with NRC Resident Inspector – Mr. McWhorter reported the FFT met with the Resident Inspectors to review the items on the agenda for the fact finding, talk about the FLEX Program, and regulatory requirements. The discussion also included the Radiation Inspection and the In-Service inspections being conducted by the NRC.

→        Containment Tour – Dr. Meshkati and Mr. McWhorter toured Containment and found it and the equipment, including Reactor Coolant Pump 1-3, to be in generally good condition.

→        Meet with DCPP Officer – the FFT met with Vice President for Business and Technical Services Ms. Maureen Zawalick to discuss Dr. Meshkati's upcoming meeting with representatives of the PG&E Corporation's Board of Director's Safety and Nuclear Oversight Committee to review their perspective on the station with regards to nuclear safety in context of the role of that Committee.

→        Review of Anonymous Notification Trends – Consultant McWhorter reported that during the January 2025 fact finding visit a discussion of the anonymous contacts by persons to the Employee Concerns Program led to a request for statistics. Mr. McWhorter reported there were 88 such contacts during 2024 reported and these were ascribed as to their subject matter on a coded spreadsheet which he stated was not inconsistent with prior years, with majority being for issues unrelated to nuclear safety or safety in general and no trends were identified. Dr. Peterson observed some persons might use the anonymous venue to raise their issues simply because it is convenient and he remarked it appears there is some confidence that items submitted will be addressed. Mr. McWhorter reported contacts for non-safety issues will not receive feedback unlike for certain safety related concerns. He reported the Nuclear Safety Culture Monitoring Panel provides a secondary review of anonymous contacts. The FFT recommended that the recommendation from the January 2025 fact finding be closed.

→        Station Update – Mr. McWhorter reported this update was beneficial.

            On a motion made by Dr. Peterson, seconded by Dr. Meshkati the April 28-29, 2025 Fact Finding Report was unanimously approved.

L.         The Chair requested Consultant Mr. McWhorter to continue his presentation and provide a summary report on the May 7-8, 2025, fact-finding visit with Dr. Budnitz. Mr. McWhorter reviewed the topics discussed with PG&E during the May 2025 visit as follows:

→        Workplace Seismic Safety – Consultant McWhorter reported this was a follow up to issues identified in December 2024 and in March 2025 and a recommendation to PG&E. He reported that the FFT was presented with documentation on the updated site standards now in place for bracing office furniture and the checklist now in use by persons assigned as process owners for specific areas during annual inspections. He reported a full round of inspections was satisfactorily performed, but a few new items were identified due to having been inspected for the first time or because of the extensive nature of the checklists. The FFT concluded the corrective actions appear appropriate and should prevent recurrence in the future. Mr. McWhorter recommended leaving the Open Item List item SC-12 open to continue Committee monitoring, but he recommended closure of the previous recommendation regarding why an extent of condition for an unbraced cabinet found in July 2024 did not prevent identification of similar conditions.

→        High-Pressure Turbine Replacement Update and Plant Tour – Mr. McWhorter reported at the time of the visit weld repairs had been completed and reassembly was in progress such that the stationary assemblies were installed in the turbine casings. The casings having been reassembled with an alignment tool and they would then be reopened, the stator assemblies aligned and verified and checked prior to installation of the rotor. In response to Dr. Peterson's query Mr. McWhorter replied that foreign material control was in place through the installation of covers on the openings where the few pipes go out from the openings in the lower casing. Dr. Budnitz commented he was impressed by the cleanliness of housekeeping in the area. The FFT concluded the planned replacement of the high-pressure turbine was proceeding satisfactorily.

→        Chemistry Program – Mr. McWhorter stated the Chemistry Program maintains primarily water chemistry in various primary and secondary systems. The industry employs a Chemistry Effectiveness Indicator (CEI) using all parameters to develop a weighted index where zero means meeting all recommended guidelines. At the time of the FFT visit Unit 1 had been at zero for more than ten months on the CEI and Unit 2 had just returned to zero on the CEI having been at 1.3 for 18 months which was caused by condenser tube leakage contamination failing to have been removed by the condensate polishers. He observed it is particularly important to avoid intrusion of contaminants into the steam generators as this can cause deposits which create areas for steam tube cracking to develop. He observed contaminants were from the tube leakage and also partly due to the ion exchange resin in the condensate polisher which can break down and release various impurities. He stated Unit 1 and Unit 2 use different ion exchange material and the product used in Unit 2 was changed. The FFT inquired concerning the condition of the condenser tubes. Mr. McWhorter reported that the plant reviewed this as part of a review under the PMO++ Program [the Preventative Maintenance Optimization ++ Program]. The decision was made not to pursue replacement of the condenser tubes, but instead to coat the tube sheets and continue to monitor and inspect the health of the system and do proactive plugging as needed using a very low plugging criteria threshold as a sizeable number of tubes can be plugged without affecting thermal performance of the condensers. The FFT found the Chemistry Program was performing well without any major issues.

→        Meet with DCPP Officer – the FFT met with Vice President Ms. Maureen Zawalick to discuss items of mutual interest.

→        Foreign Material Exclusion Program – Consultant McWhorter reported this was a periodic review which the Committee tries to do after outages, although this visit was at the end of an outage. The Foreign Material Exclusion Program (FME) is intended to prevent incursion of foreign material into any of the plant systems that depend upon being clean and free of impurities. He reported there have been significant revisions to the governing procedures which were reviewed by the FFT. The change primarily better aligned the program with industry conventions. The FME addresses events where foreign material causes damage to equipment or affects the plant in some way, threats where an item is found where it should not be but causes no impact, and conditions where violations of procedures are promptly remedied. He reported over the last three outages the number of conditions has come down from 15 (1R24) to 3 (2R24) to 2 (1R25). For 1R25 there were some significant deficiencies/conditions identified on how the covers were installed on various parts of the generator. During 1R24 there was one threat when a component cooling water motor was opened for maintenance and was found to have disintegrating debris from a rag left inside which did not cause the motor to fail to perform its function. The FFT concluded the FME Program was performing well with no major issues.

→        Intake Structure Tour – the FFT toured the Intake Structure to assess the condition of the structure with regards to concrete and other degradation. Mr. McWhorter reported that overall the condition of the Intake Structure was good and the facility was being maintained to a high standard. A small amount of concrete degradation was observed and an inspection program is in place concerning repairs. Dr. Budnitz observed the facility is in a marine environment and was found to be very clean. Mr. McWhorter displayed photos of the FFT at the Intake Structure. He commented that during the visit Auxiliary Saltwater Pump 1-1 was visible as the watertight door was open and it was in apparent good condition with only minor corrosion at the base. The FFT concluded conditions at the Intake Structure were good.

→        Observe Senior Leadership Team Outage Briefing – Mr. McWhorter reported this was the same meeting he discussed in his previous presentation and the FFT conclusions were the same, in that the meeting was conducted efficiently and effectively.

→        Large Transformers - Mr. McWhorter reported large transformers are the 14 transformers that step-up or step-down voltage connected to the 230kV or 500kV transmission systems. Six main transformers step the generator voltage up to grid voltage, four auxiliary transformers step grid voltage down for use when the plant is operating online, and four start-up transformers step down grid voltage for use in the plant when it is offline. He reported that over past years the plant has completed addressing multiple issues and performing maintenance on the large transformers including draining and replacing oil, inspecting internals, repairing leaks and fans, and addressing external corrosion. He reported the PMO++ Program developed new life cycle management plans for the transformers which are under review and not yet complete. Mr. McWhorter reported this summer the spare transformers now located next to the in-service transformers will be relocated to a new concrete pad up the hill behind the plant and near the switchyard to remove them and continue to maintain them away from a corrosive salt spray environment. The FFT concluded the transformers are in acceptable health with a considerable amount of maintenance having been performed.

→        Observe Outage Scope Review Team and Daily Notification Review Team Meetings- Mr. McWhorter reported these teams review all Notifications related to equipment and make the determinations as to the priority of the corrective actions. He reported that the Daily Notification Review Team meetings during an outage are integrated with the Outage Scope Review Team meetings such that the issues are assigned a priority and the decision is made to address the issue during the outage or later online or at the next refueling outage. The FFT concluded the meeting which addressed approximately 40 Notifications was conducted efficiently and effectively.

→        Observe Corrective Action Review Board (CARB) Meeting – Consultant McWhorter stated the CARB represents the highest level of review of items in the Corrective Action Program and usually focuses on one to three specific items at each meeting. The CARB also reviews Corrective Action Program assignments that are considered to be the oldest to ensure they are being pursued to resolve open Level 1 and Level 2 assignments and work group evaluations. The CARB also conducts another review of the Notifications. The FFT concluded the meeting was conducted effectively and accomplished its objectives. In response to Consultant Kadak's query Mr. McWhorter stated the Performance Improvement organization is responsible for identifying trends in Corrective Action Program items and the identified trends are part of the CARB's agenda. In response to Dr. Meshkati's question as to whether the CARB is the body that decides on a hierarchy for cause evaluation, root cause evaluations, and common cause evaluations Mr. McWhorter stated that was among the CARB's review functions, but the decision as to what level of causal review is employed is made by the Notification Review Team using criteria in the procedures and then reviewed and confirmed by the CARB and other plant organizations. Dr. Budnitz reported that a high level of confirmation is required to initiate a root cause evaluation which Dr. Meshkati commented has a safety culture assessment associated. Dr. Meshkati commented on the importance of making the decision on the causal evaluation of an incident. Mr. McWhorter identified the four levels of causal evaluations in descending order, with the most extensive listed first, as: root cause evaluation, cause evaluation, work group evaluations and common cause evaluations. He reported there have been 17 cause evaluations in the last two years with a greater number of work group evaluations. In response to Dr. Meshkati's question as to whether the recurring issue with the ASW System pump repair should have been assigned a common cause evaluation Mr. McWhorter commented the root cause evaluation has a very extensive extent of condition component that reviews whether the problem has occurred elsewhere in the plant and Mr. McWhorter suggested Dr. Meshkati may want to explore this question further with the plant. A PG&E representative recommended that Dr. Meshkati raise his question about the ASW pump with the Performance Improvement organization. 

→        Station Update – the FFT received a project update for projects completed in the outage.

→        Management Observation Program – Mr. McWhorter reported this was a routine review of a formal program to have supervisors observe workers and staff in the field performing various tasks to ensure they are following site standards. He reported the program has evolved over five to seven years and the emphasis is now on making numerous observations and documenting the results electronically as part of a station-wide tracking program which can track and assess performance on different issues specific to each department. He reported the results of these observations are discussed at department review meetings. In response to Dr. Kadak's comment Mr. McWhorter stated the DCISC is provided with high level performance improvement summaries for each department. Mr. McWhorter stated it is his observation that if something is identified as a trend, a trend Notification is then initiated and pursued. Dr. Budnitz stated during the discussion with the FFT he was impressed with the level of detail the DCPP personnel were aware of through their analyses and the level of understanding they displayed. The FFT concluded the Management Observation Program was being well implemented by DCPP.

            On a motion by Dr. Meshkati, seconded by Dr. Peterson, the May 7-8, 2025 Fact Finding Report was unanimously approved.

XXX  CONCLUDING REMARKS & DISCUSSION BY COMMITTEE MEMBERS

            OF FUTURE DCISC ACTIVITIES                                                            

                        M.        Future Actions by the Committee.    

                        N         Further Information to Obtain/Review.

                        O.        Confirmation of Future Site Visits, and Public Meetings.

            Dr. Peterson observed all of the above three agenda items had been fully covered by the Committee during its previous discussions during this meeting. He then extended the thanks of the Committee to PG&E and to Ms. Lopez and Mr. Soenen for their capable support of the Committee, to the technicians of AGP Video for their ability to broadcast and record the meeting. and to the members of the public who contributed and attended during the course of the meeting. Dr. Budnitz reported that his seat on the Committee is now up for and pending appointment by the California Attorney General and he is unsure whether he will be reappointed and accordingly this could be his last meeting as a Member of the DCISC after 18 years of service. Dr. Meshkati extended thanks to Counsel Rathie and Consultants McWhorter and Wardell for their efforts.

XXXIII ADJOURNMENT OF THE ONE HUNDRED AND ELEVENTH PUBLIC MEETING

            There being no further business, the one hundred and eleventh public meeting of the Diablo Canyon Independent Safety Committee was adjourned by its Chair Dr. Per F. Peterson, at 3:21 p.m.