21st Annual Report, Executive Summary, Conclusions and Recommendations
History and Introduction
The Diablo Canyon Independent Safety Committee (DCISC) was established as part of the June 24, 1988 settlement agreement which arose from the rate proceedings for the Diablo Canyon Nuclear Power Plant (DCPP). The DCISC was formed in late 1989 with the appointments of Committee Members and began formal review activities and meetings on January 1, 1990. The original settlement agreement (D.88-12-083) was terminated by the California Public Utilities Commission (CPUC) in its decision to open the state electricity markets to competition on January 1, 1998; however, under the provisions of the Commission’s Decisions 97-05-088, issued on May 21, 1997, and 04-05-055, issued on May 27, 2004, the DCISC will continue to function and fulfill its responsibilities as established under the terms of the 1988 settlement agreement.
On May 27, 2004, the CPUC issued Decision 04-05-055. In its decision, the CPUC changed the nomination procedures by eliminating from the process the participation of PG&E and the Dean of Engineering at the University of California at Berkeley; modified the requirements for membership on the DCISC to add “knowledge and background in nuclear safety issues” to the “experience in the field of nuclear power facilities” and modified the DCISC’s mandate to require it to undertake public outreach in the community. The Decision concluded the DCISC should retain the discretion to determine how best to accomplish its mandate and that the DCISC shall otherwise continue to exist and to operate and continued funding through cost-of-service rates. To implement this directive the DCISC has continued to expand its public outreach as described in Section 8.0 Public Input and Outreach and continues to consider additional outreach activities.
On January 25, 2007, the CPUC issued Decision 07-01-028. The CPUC had previously adopted new practices and expectations for the DCISC without concurrently restating the Committee’s charter to reflect the changes. In its decision, the CPUC granted the DCISC application for authority to restate its charter including the incorporation into the Restated Charter of several terms, conditions, changes and clarifications necessitated by, and previously authorized by, the CPUC which govern the composition, responsibilities and operations of the Committee. In its decision, the CPUC found the Restated Charter to be in the public’s interest as it reflects the latest authority and obligations of the DCISC. The Committee’s application was unopposed.
The original settlement agreement provided for a three-member Independent Safety Committee for the purpose of “reviewing and assessing the safety of operations of DCPP”. The members serve three-year staggered terms and remain on the DCISC until a new appointment or their reappointment is made. To fill an expired term or a vacancy the CPUC issues a public notice soliciting interested persons. Under the revised process in accordance with the restated charter, candidates are selected by the CPUC from the applications plus the incumbent, if willing to serve. The candidates must be “persons with knowledge, background and experience in the field of nuclear power facilities and nuclear safety issues.” From the list of candidates, the new or returning member is appointed by the Governor of California, the Attorney General of California or the Chairperson of the California Energy Commission (CEC), whichever made the original appointment.
The Committee Members during this period were as follows:
- Dr. Robert J. Budnitz, a scientist with the University of California Lawrence Berkeley National Laboratory, appointed by the California Attorney General, served as a Member for the period October 10, 2007–June 30, 2010 and was reappointed for a second three-year term beginning July 1, 2010. Dr. Budnitz served as Chair for the full period. Dr. Budnitz’s term ends June 30, 2013.
- Dr. Per F. Peterson, Professor of Nuclear Engineering and Chair of the Nuclear Engineering Department at the University of California–Berkeley, appointed by the California Attorney General, served as a Member for the period September 2, 2004–October 9, 2007. Dr. Peterson was subsequently appointed by the Governor of California to a three-year term ending June 30, 2011.
- Dr. Peter Lam, Administrative Judge Emeritus of the U.S. Nuclear Regulatory Commission, appointed by the Chair of the California Energy Commission, commencing July 1, 2009 and ending June 30, 2012.
Overview of Activities during the Current Period
The Committee regularly performs the following activities:
- Three sets of two-day public meetings each year in the vicinity of the plant
- Three tours of the Diablo Canyon Nuclear Power Plant (DCPP) each year with members of the public
- Numerous fact-finding visits by individual Committee Members and Consultants to assess issues, review plant programs and activities, and interview PG&E personnel
- Visits by the DCISC Members and legal counsel to offices of the CPUC and appointing officials (the Governor of California, California Attorney General and California Energy Commission) to update them on DCISC Activities
- Use of several regular part-time technical consultants to perform assessments and reviews
- Use of legal counsel to advise the Committee on its activities
- Use of expert consultants, as needed
The DCISC issues a report for each reporting year, which runs from July 1 to June 30. The report is approved by the Committee Members at the fall public meeting following the end of the reporting period. The first six-month interim report and subsequent twenty annual reports covered the periods January 1, 1990–June 30, 2010.
This twenty-first annual report covers the period July 1, 2010—June 30, 2011.
Three public meetings were held in the vicinity of the plant in San Luis Obispo, California during this reporting period. The following significant items were reviewed:
- DCPP performance and operational events
- Refueling outage overviews, plans and results
- Review of DCPP performance indicators
- Human error performance improvement program
- Nuclear Safety Oversight Committee (NSOC) activities
- Steam Generator replacements
- Radiation exposure during refueling outages
- On-Site Spent Fuel Storage Plans (Independent Spent Fuel Storage Installation [ISFSI])
- Plant security review for effects on plant safety
- Problem Identification and Resolution Program (Corrective Action Program)
- Operating Experience Program
- Online Maintenance
- Radiological Release Reports
- Transformer malfunctions and oil leaks
- Reactivity Management Program
- Engineering, Operations and Maintenance Organizations
- Emergency Preparedness (EP)
- Management Review Committee
- Fire Protection
- Public Outreach
- Equipment Reliability
- Response to Winter Ocean Storms
- Error Prevention tools and Human Performance and Safety Training
- Component Mispositioning
- Single Point Vulnerabilities
- Employee Concerns and Differing Professional Opinion Program
- Containment Fan Cooler Reverse Rotation
- INPO (Institute of Nuclear Power Operations) Evaluations
- Natural Phenomena (earthquakes and tsunamis)
- DCPP Business Plan Support of Safety
- Quality Verification Organization, Performance Reports and Audits
- Regular discussions with NRC Resident Inspectors
Many other items were reviewed in eleven fact-finding visits, inspections and tours at DCPP by individual Committee Members and consultants. DCISC Members visited representatives from the Attorney General’s Office and California Energy Commission to provide updates on DCISC Activities, to discuss agency concerns and comments, and to provide copies of the Committee’s Annual Report.
Public input and questions were received at the public meetings, and by telephone, letter and E-mail. Members of the public spoke at two of the three DCISC public meetings. The DCISC has responded to all of their questions, concerns and requests during this period.
- Overall Conclusion
- The DCISC concludes that PG&E operated DCPP safely during the period July 1, 2010—June 30, 2011.
Based on its activities, the DCISC has the following specific conclusions from the major review topics examined during the current reporting period (references to sections of this report are shown in parentheses). Conclusions are based on, but may vary from, information contained in Committee Fact-finding Reports in Exhibit D in Volume II of this report.
- The DCISC received regular reports on the Nuclear Regulatory Commission (NRC) Performance Indicators, DCPP License Event Reports (LERs) sent to NRC, and NRC Inspection Reports and Enforcement Actions (violations) at each of its public meetings as well as copies of these documents throughout the reporting period.
- The Committee notes that, although the NRC concluded that, “Overall, Diablo Canyon Nuclear Power Plant, Units 1 and 2, operated in a manner that preserved public health and safety … ,” it identified 36 Non-cited Violations, four Severity Level IV violations, and continued a substantive crosscutting issue. The increase in number of these violations and the crosscutting issue (in problem identification and resolution) are concerns to the DCISC. The DCISC plans to augment its review of DCPP NRC regulatory performance during the next reporting period. (Section 3.5)
- Operations had performed satisfactorily in the normal operation of the plant. Actions to address component mispositionings, steam generator iron and sulfate concentrations, and operator burdens appeared to be appropriate. The Operational Focus Action Plan was well conceived and appeared to be getting good results. Implementation of the Operations Revitalization Action Plan appeared to be obtaining good overall results with respect to improving the relationship between Operations managers and workers. One worker concern was being addressed by DCPP management and was reviewed and appeared to have no impact on nuclear safety. (4.1.3)
- The DCPP Maintenance Program appeared to be functioning satisfactorily. No concerns were identified pertaining to nuclear safety. However, a sharp decline was observed during the past five years with regard to personnel awareness of the elements of Post Maintenance Testing (PMT) and its importance. This was concluded to be due primarily to the attrition of key experienced personnel. Improvements to better support PMT were also found to be needed in a number of areas such as clarity of procedures and work packages, Operations Verification Testing, and the involvement of a Senior Reactor Operator early in the process. DCPP’s Foreign Material Exclusion (FME) Program performance was noted to have degraded during refueling outages 2R15 and 1R16 but showed an improving trend after 1R16 in October 2010. DCPP was making improvements in the program to better address outage and non-outage FME performance. The DCPP On-Line Maintenance (OLM) Program, continued to improve by adopting better risk analysis procedures and tools and by upgrading OLM to the station program level. (4.2.3)
- Collectively, the topics, issues, and activities associated with addressing DCPP problem evaluation were extensive and detailed. DCPP had developed an extensive action plan and had begun to utilize a wide array of performance indicators to track progress on this issue. Many actions were well underway. The DCPP Air Operated Valve (AOV) Program appeared to be satisfactory. Valves were appropriately categorized for priority and testing and were tested on a schedule during outages. Testing had been successful. A June 2010 self-assessment identified no nuclear safety, programmatic, or regulatory violations but did reveal some gaps to excellence and enhancements, which were documented in the Program Health Report for action and tracking. The DCPP Environmental Qualification Program (EQP) for safety-related electrical equipment appeared sound. A self-assessment found the EQP to be effective in meeting the regulatory requirements of 10CFR50.49. The EQP appeared to be in a good position to assure applicable DCPP equipment is compliant with the 20-year plant life extension. The nearly completed initial Phase I work of the Environmental Qualification (EQ) Program had provided a good foundation for moving forward with Phase II, the main project initiative.
- DCPP’s Margin Management Program appeared to be functional and healthy. Margin issues had been identified and prioritized. Responsibilities, actions, and completion dates/horizons had been established for identified issues. The Margin Management Committee appeared to be serving as a vehicle, not only for reviewing margin issues, but also for reinforcing margin concepts. Improvements in the System Engineering Program combined with those in the Plant Health Committee process appeared to have good potential for maintaining DCPP systems healthy. DCPP system health had improved since these changes were made. DCPP had responded aggressively to the significant performance gaps identified in its engineering evaluation thoroughness and rigor. DCPP had developed a detailed, comprehensive Evaluation Thoroughness Action Plan that appeared to address the identified performance gaps; however, DCPP had not satisfactorily completed its first significant measure of corrective action: a self-assessment to have been performed in 2010. (4.3.3)
- DCPP human performance (HP) is good and improving overall with plant-wide performance better than a progressively tightening goal and over 529 days without a clock reset, which is an indicator of outstanding performance. Most departments are within their goals with one, Operations, slightly better than goal. (4.4.3)
- The Premier Survey, like other employee surveys conducted on a regular basis, remained effective both as a communication tool between management and employees and as a measure of employee thinking. To the extent that this company-wide survey communicates with company-wide management, it can play a special role. The results of the survey were reported to be similar to those of earlier DCPP surveys. The action plan resulting from the Premier Survey was under development. The action plan to increase visibility of the DCPP Employee Concerns Program appeared to be appropriate. (4.5.3)
- DCPP’s Performance Improvement Program continues to be strengthened with the addition of the Performance Improvement Review Board, a management board which monthly meets to review the program and specific items, which are lagging, and the Performance Improvement Action Plan, a multi-faceted plan to integrate the results of several assessments and reviews of the program.
- DCPP’s Corrective Action Program (CAP) has for some time continued to undergo significant reviews, assessments and audits by both internal and external organizations. Actions continue to be taken to respond to the reviews. The NRC has identified a substantive crosscutting issue in the DCPP Problem Identification and Resolution area, indicating unsolved problems with the CAP. The DCISC will continue to monitor the CAP.
- DCPP’s Operating Experience (OE) Program appears to be in jeopardy of becoming resource-limited if the function is reduced to just a single person performing OE duties. The DCISC will monitor this situation (4.6.3)
- Responses to the July 7, 2010 simulated event by Control Room personnel were generally methodical and effective. However, improvements were needed in the performance of the Operational Support Facility with respect to on-site radiological controls. Media briefings in the Joint Information Center (JIC) appeared to have improved substantially.
- The August 11, 2010 NRC-evaluated DCPP emergency exercise Joint Information Center performance observed by the DCISC was much improved from prior exercises/drills in that news releases, press conferences, and use of the Site Vice-President as public spokesperson combined for timely, accurate, and understandable information release. The plant operational response to the emergency was, as in previous exercises observed by the DCISC, professional and effective.
- At DCISC’s June 2011 Public Meeting, DCPP’s presentations of strengths and areas for improvement regarding the EP drill rehearsal in July 2010, the NRC’s graded emergency exercise in August 2010, and the unplanned release of carbon dioxide in June 2010 were focused, self-critical, and consistent with information accumulated by the DCISC.
- Significant enhancements and expansions have been completed on DCPP emergency dose assessment systems, which exceed regulatory requirements and increase the level of protection for the public in the event of an unplanned radiological release. (4.7.3)
- DCPP’s Probabalistic Risk Assessment (PRA) Group is being returned to a somewhat satisfactory staffing level, following several years of decline and use of contractors to accomplish its analyses. The decline came about due to loss of key personnel who have been difficult to replace. The Group is progressing well on several important PRA fronts, including a Fire PRA, updated Seismic PRA, and the performance-based PRA analysis to support the move to National Fire Protection Association (NFPA) Standard 805. DCPP has finally caught up with industry in its use of Safety Monitor, which is used to gauge the risk of removing components from service for on-line maintenance. The DCISC will continue to closely monitor PRA activities at DCPP. (4.8.3)
- DCPP performed a mid-cycle assessment of its progress in satisfying the Areas for Improvement (AFIs) from the 2009 Institute of Nuclear Power Operations (INPO) evaluation. DCPP was preparing for its August 2011 evaluation. The DCPP Nuclear Safety Oversight Committee (NSOC) is satisfactorily staffed with strong external members and their review of issues is appropriately intrusive, focusing on the most important safety issues. (4.9.3)
- DCPP radiation releases this period, as in previous periods, were very small fractions of Technical Specification and regulatory limits. The DCPP Radiation Protection (RP) Group performed successfully in Outage 1R16 in working to keep the plant Collective Radiation Exposure of 118.8 Person-Rem below the plant goal of 126 Person-Rem. The replacement of the Reactor Vessel Closure Head and Integrated Assembly contributed 36.2 Person-Rem to the total exposure, compared to a planned exposure of 32.6 Person-Rem for the project. This total exposure, however, places DCPP in the industry fourth quartile, a position RP is working to improve. Performance in Outage 2R16 was significantly improved with total radiation dose of 29.7 person-Rem due primarily to reduced in-containment major equipment work. RP is taking a forward-looking approach to the next sets of outages to keep lowering the exposures. The DCISC will continue to monitor DCPP’s progress in radiation protection. (4.10.3)
- QV continues to identify items that need correction, in particular gaps in the DCPP Corrective Action Program evaluation thoroughness, which was also identified by the NRC as a substantive cross-cutting issue. The Key Gaps that are listed are clear and well supported. The process of highlighting continuing Key Gaps and escalating issues as deemed necessary appears sound and effective. Because of the number and significance of QV-escalated items and Top Concerns, the DCISC will increase its monitoring and review in the QV area. (4.11.3)
- DCPP nuclear fuel has performed well, especially Unit 1 fuel, which has had 12 cycles of defect-free fuel. Unit 2 fuel is improving, having had three cycles defect-free, preceded by three clean cycles followed by a debris-caused leak. DCPP has experienced fuel assembly thimble tube wear in some instrumented assemblies due to flow-induced vibration. This is becoming an industry problem, which is being closely by DCPP and its fuel vendor, Westinghouse. DCPP is also evaluating a transition to a 24-month refueling outage interval, which would avoid the need to have more than one refueling outage per year and would simplify outage planning. The DCISC should follow this issue. (4.12.3)
- DCPP appeared to be managing the Equipment Reliability (EP) Program well. ER at DCPP had improved as a result of the Preventive Maintenance (PM) Program and PM Optimization. (4.13.3)
- During 2010 DCPP received important support from the STARS association of nuclear plants in a number of important areas such as cross-cutting issues, corrective action, self-assessment, and licensing basis verification. DCPP’s overall composite performance indicator for the first three quarters of 2010 compared favorably within the STARS group and within the nuclear industry as a whole. DCISC’s next review of DCPP’s participation in STARS need not be until about two years hence. (4.14.3)
- DCPP has dealt effectively with most equipment and system problems and is focused on improving system health. DCPP’s Plant Health Committee has been improved to focus more on system/component health and meet more frequently, and overall system health has improved. The System Engineer/Component Program continues to be effective. (4.15.3)
- All eight DCPP new, replacement steam generators (SG) were determined to be in very good condition after their first inspections, which were required by Plant Technical Specifications to be performed during their first refueling outage after the SG replacements. (4.16.3)
- DCPP successfully completed its 1R16 and 2R16 refueling outages in which most goals were met, except that outage durations were longer than predicted due to emergent work and some rework. Nuclear safety was upheld. (4.17.3)
- DCPP appears to have an effective program for maintaining its safety/security interface and satisfactory plans and resources to implement its cyber-security program. The DCISC will follow up on both of these during the next reporting period. (4.18.3)
- DCPP has successfully completed construction of its Independent Spent Fuel Storage Installation (ISFSI) and completed two major loading campaigns of 16 casks for a total of 512 spent fuel assemblies. The campaigns have all gone according to plans and expectations. DCPP is ordering additional casks and planning to construct more concrete pads to accommodate additional spent fuel at the ISFSI. At the end of 60 years plant life both the Spent Fuel Pool and the ISFSI will be full. (4.19.3)
- DCPP is in a unique seismic area with the potential for large earthquakes, and its design basis takes this into account. The DCISC notes that little progress appears to have made during the period late 2010–early 2011 regarding protecting personnel in office spaces from moving objects that could cause personnel injury and/or impede response to an emergency in the event of an earthquake. Performance appears to have improved considerably in the area of DCPP’s Seismically Induced Systems Interaction Housekeeping Program since mid-2010. The preliminary results of the PG&E analysis of the Shoreline Fault rupture showed that the DCPP seismic design basis remained valid for any of three possible scenarios: either (1) as a single segment, or (2) as all three segments together, or (3) as all three segments together combined with a Hosgri rupture. (4.20.3)
- DCPP continues develop its analysis to support conversion from NRC’s current deterministic fire protection regulations to the performance-based, risk-informed National Fire Protection Association (NFPA) 805 standard, which has been accepted by NRC. DCPP’s Fire Protection System is currently in White (acceptable) health; however, it had been Red and Yellow (both unacceptable, but operable) for a long time, and the DCISC will continue to monitor it closely. (4.21.3)
- Although the July 2010 DCPP self-assessment of Technical and Engineering Training Programs was based upon comparisons to industry best practices rather than to minimum acceptable performance. The Negative Comments in the assessment report both individually and collectively reflect a lack of rigor in some aspects of DCPP Technical and Engineering Training Programs. The DCISC will continue to follow this issue in the next reporting period. (4.22.3)
- The DCPP License Renewal proceeding continues to progress with NRC’s draft favorable Safety Evaluation Report (SER) having been released and the Advisory Committee on Reactor Safeguards (ACRS) Sub-Committee meeting completed. There are several open technical issues with the NRC, but these are being resolved, meaning that the technical portion of the application is being completed. The NRC has admitted four contentions by intervener San Luis Obispo Mothers for Peace. It appeared that the license extension could be issued in early 2012, if the environmental review were to proceed on-schedule and the contentions were to be satisfactorily settled in the hearings; however, on April 10, 2011, PG&E submitted a request to the NRC to defer its issuance of the DCPP license renewal until certain seismic reviews are completed in 2015.
- The DCISC has responded to the California Energy Commission’s request that it look into whether there is a nexus between the Hosgri and Shoreline Faults and reactor vessel pressurized thermal shock (PTS). The DCISC concluded that there is no direct relationship between having earthquakes, even very large earthquakes, and PTS issues associated with neutron embrittlement of the reactor vessel. This is in agreement with both PG&E’s and NRC’s initial conclusions (4.23.3)
- A possible mandate for plant retrofit to use closed, salt-water cooling towers in the future could have major impacts on plant safety. A range of adverse nuclear safety impacts is known qualitatively at this time and is of concern to the DCISC. The DCISC will continue to take seriously the charge to review the safety impacts of the elimination of Once Through Cooling (OTC) at DCPP and provide analysis and input to the process. (4.24.3)
- As a result of the Japanese Fukushima Nuclear Plant earthquake and tsunami damage, the U.S. Nuclear Regulatory Commission, nuclear industry groups, and individual plants are reviewing plants’ capabilities to handle “beyond design basis” events, i.e., events beyond which the plants were originally designed. Because of substantial design margins and differences between U.S. and Japanese designs and operating and emergency response procedures, U.S. plants, especially Pressurized Water Reactors similar to DCPP, have different capabilities than Japan to handle beyond design basis events. PG&E has established a formal team to determine the plant’s capabilities and recommend improvements. Based on Fact-finding meetings and public meetings on this subject, the DCISC believes that PG&E is taking the appropriate actions. (4.25.3)
- Concerns are items which, while not necessarily warranting recommendations, the DCISC believes need continuing Committee review and improvement or attention by PG&E. Concerns are monitored more actively and at a higher-level by the Committee than other items. The DCISC concerns are as follows:
- NRC identified 36 Non-cited Violations, four Severity Level IV violations, and continued a substantive crosscutting issue. The increase in number of these violations and the crosscutting issue (in problem identification and resolution) are concerns to the DCISC. The DCISC plans to augment its review of DCPP NRC regulatory performance during the next reporting period. (3.1.6)
- DCPP’s Corrective Action Program (CAP) has continued to undergo significant reviews, assessments and audits by both internal and external organizations. Actions are being taken to respond to the reviews. The NRC has continued its substantive crosscutting issue in the DCPP Problem Identification and Resolution area, indicating unsolved problems with the CAP, a similar situation which occurred in 2004. The DCISC will step up its review of the CAP. (4.6.3)
- Although the studies examining the possible installation of a Once Through Cooling capability for DCPP’s main condensers are still in progress, the DCISC expresses a significant initial concern regarding the potential impact that such a modification would have on nuclear plant safety and reliability (4.24.3)
- DCISC recommendations are listed below along with references to sections where recommendations originate. Recommendations are based on, but may vary from, information contained in Committee Fact-finding Reports in Exhibit D, Volume II of this report.
- Recommendation R11-1
- Due to the substantial increase in the numbers of NRC Non-cited Violations and Severity Level IV Violations over the last two reporting periods and because the NRC Substantive Crosscutting Issue in Problem Identification and Resolution still exists, the DCISC recommends that DCPP re-examine its earlier Root Cause Analysis for effectiveness and consider an independent review of its corrective actions by Quality Verification, the Nuclear Safety Oversight Committee, or the Institute of Nuclear Power Operations in an assist visit. (3.5)
- Basis for Recommendation:
- Licensee Event Reports, Violations, and the Substantive Crosscutting Issue in PI&R are related issues because they all deal with the identification and resolution of plant events. If there is a common cause or similar causes for these negative trends, DCPP should identify and resolve them. The DCISC notes that the DCPP Corrective Action Program has undergone many reviews and assessments in the last several years apparently without an effective, sustainable resolution.
The DCISC had a similar recommendation in the previous reporting period as follows:
Recommendation R10-1: Due to the increases in the numbers of Licensee Event Reports and Severity Level IV Violations and because of the newly re-identified NRC Substantive Crosscutting Issue in Problem Identification and Resolution, the DCISC recommends that DCPP perform a comprehensive analysis to determine the cause of these negative regulatory trends.
DCPP responded as follows:
“PG&E has performed multiple analyses, as documented in the Corrective Action Program, for these events. A common cause analysis was performed to examine the number of traditional enforcement violations (as documented on SAP Notification 50331845). This common cause analysis was approved by the Corrective Action Review Board on October 5, 2010.
The substantive cross-cutting issue in problem evaluation was analyzed in the Corrective Action Program via a root cause analysis (as documented in SAP Order 60024480). This root cause analysis was approved by the Corrective Action Review Board on June 7, 2010.
Both these Corrective Action Program documents were the subject of an inspection by Nuclear Regulatory Commission inspectors in December 2010. The NRC inspectors concluded that the corrective actions appear to be appropriate and on target, but lacked sufficient run-time to demonstrate their effectiveness at he time of the inspection.”
The conclusions in the December 2010 inspection report are encouraging, but the DCISC notes that the substantive cross-cutting issue still exits.
- Recommendation R11-2
- The DCISC recommended that DCPP initiate and promptly complete its first self-assessment of the significant gap in the thoroughness and rigor of its engineering evaluations, which was to have been completed by the end of 2010. (4.3.3)
- Basis for Recommendation:
- The DCISC Fact-finding Team requested the Engineering Evaluation Rigor Improvement Action Plan self-assessment (a self-assessment to be conducted in late 2010 concluding performance is improving); however, it had been improperly performed, was not complete at the time, and a definitive completion date was not provided. This is a concern to the DCISC because this was to have been the first significant measure of a significant problem at DCPP. The DCISC should recommend that this self-assessment be promptly completed.
- Recommendation R11-3
- DCPP’s Post Earthquake Response Procedure should be expanded to require examination of Spent Fuel Pool (SFP) levels after an earthquake and sampling locally for indications of possible SFP liner leakage. DCPP should also consider providing permanently installed, remote wide-range SFP level monitoring capability. (4.20.3)
- Basis for Recommendation:
- DCPP’s Post Earthquake Response Procedure, CP M-4, does not require a visual inspection of SFP level as a post earthquake response action. Significant inventory loss from the pool would result in a low-level alarm, and the response procedure for the alarm would prompt an inspection. It is possible that an earthquake could not only cause a decrease in SFP level and create a leak in the SFP liner but could also disable the instrument that activates the SFP Low Level Alarm. Sampling for liner leakage would help verify the integrity of the pool, and thus allow plant personnel to focus subsequent efforts on responding to other effects of the earthquake without concern about potential losses of pool inventory.
- Recommendation R11-4
- DCPP needs to develop and implement a schedule for taking the necessary actions to brace furniture appropriately throughout the station, and to better educate plant staff about seismic hazards and seismic safety. (4.20.3)
- Basis for Recommendation:
- Not much progress in seismically securing heavy furniture appears to have been made during 2011. Some aspects of the design and testing room for the Auxiliary Building Control Board Replacement Project, Room 206 in Building 102, need to be more in keeping with seismic standards. Specifically, several tall shelving units containing boxes were not braced to the wall and other tall stands/bookcases were freestanding and away from the walls of the room. One desk had a large number of heavy boxes stored at a high elevation above the desk. The file cabinets in the Shift Manager’s office, which had been noted not to have been braced during the May 2010 Fact-finding Visit, were still in the same condition. While these file cabinets may not be tall enough to formally require seismic bracing, they are very heavy and are located a few feet from a large table, so if they were to fall over during an earthquake they would pin operators against the table and potentially cause serious injuries.
Finally, the DCISC appreciates PG&E’s cooperation in arranging and providing information for DCISC Fact-finding meetings and tours at DCPP and for the high quality and professional presentations at DCISC public meetings.