4.0 Summary of Major DCISC Review Topics, 17th Annual Report - July 1, 2006 thru June 30, 2007
4.17 Outage Management
4.17.1 Overview and Previous Activities
The DCISC monitors PG&E’s outage plans, actions, and results in the following ways:
- Review of outage safety evaluations and plans
- Regular Fact-finding meetings to discuss planned major modifications, inspections, maintenance and activities
- Regular reports from PG&E at DCISC Public Meetings on outage plans and outage performance, noting any special situations or problems affecting safety
- Visits to DCPP during outages to monitor the Outage Coordination Center, Control Room and activities of interest
- Reviews of documentation and reports of outage activities such as steam generator tube inspections, major equipment problems, and events affecting safety
PG&E completed its thirteenth Unit 1 & 2 refueling outages (1 R13 & 2R13) during the 2005-2006 reporting period. Since the DCISC began review of this subject in 1990, outage management performance has steadily improved as shown in the table below. PG&E expects its outages can routinely run in the high-twenty to low-thirty day range.
Other outage indicators also are showing continuous improvement. With the exception of anomalous 1R9 radiation levels, radiation exposure and personnel injuries have been generally declining in the last three outages as follows:
| Outage Duration (days) | Radiation Exposure (person-Rem) | Personnel Safety (recordable injuries) | ||||
|---|---|---|---|---|---|---|
| Outage | Unit 1 | Unit 2 | Unit 1 | Unit 2 | Unit 1 | Unit 2 |
| R10 | 40.4 | 29.5 | 162 | 108 | 2 | 1 |
| R11 | 30.3 | 33.5 | 138 | 125 | 4 | 2 |
| R12 | 77.5 | 57.0 | 149 | 98 | 5 | 0 |
| R13 | 41.0 | 38.8 | 116 | 74 | 5 | 3 |
| R14 | 29.8 | - | 103 | - | 6 | - |
The DCISC reviewed the following during the previous reporting period.
- Outage 1R13 Planning, Safety Plan, Tour and Results
- Outage 2R13 Planning, Safety Plan, Tour and Results
The DCISC concluded in the previous period that it appeared that PG&E managed the 1R13 and 2R13 outages effectively but experienced a larger amount of emergent work and more restart difficulties than normal. Outage radiation doses are trending lower. The DCPP outage lessons-learned program has improved.
4.17.2 Current Period Activities
The DCISC reviewed the following outage-related topics during the current period:
- Outage 2R13 Safety Plan
- Outage 1R14 Work and Safety Plans
- Readiness for Restart Program
- Outage 1R14 Results
Outage 2R13 Safety Plan
The DCISC Fact-finding Team met with Brad Hinds, Outage Manager, at the August 2-3, 2006 Fact-finding Meeting (Volume II, Exhibit D.1, Section 3.2) to review the update on the Outage Safety Plan.
Due to disturbing trends in the number of loss–of-cooling events in the industry, DCPP completed a comprehensive overhaul of its outage safety plan in 2005. As a result, DCPP’s shutdown defense-in-depth (DID) program is more effective and practical. It ensures that forced core-cooling methods are maintained at all times. It also ensures that should the required forced cooling system or support systems fail, at least one passive core cooling method is available until forced cooling can be restored. It also identifies the necessary plant conditions that make passive cooling capability either delayed or unavailable and minimizes the time that the plant is in these “transition periods.”
The safety plan provides operators with comprehensive guidance for taking appropriate mitigating actions and ensures that the plant condition and configurations are maintained to support the basis for that guidance. In addition, methods are established for evaluating emergent conditions that threaten or reduce DID. These factors reveal that DCPP has kept a robust focus on event mitigation and Containment closure capability in its program. While the DCPP DID program is effective and practical, it appears from internal and external operating experience that there is continued justification for strengthening DCPP’s means of event prevention.
INPO has requested all utilities to perform a detailed assessment of the shutdown DID. DCPP completed their assessment in March-June, 2006. As part of the INPO request, there was a set of 35 questions for each utility. The Shutdown DID self-assessment was performed in March-June, 2006 by DCPP employees and peers from Callaway Plant. This self-assessment identified 5 strengths, 3 areas for improvement, and 8 recommendations. The self-assessment also responded to the 35 questions on the INPO DID review areas.
The final report should be out by the end of August 2006. The outage safety plan for 1R14 will incorporate the improvements and recommendations made in this assessment.
DCPP had made improvements in their outage safety plan in 2005. The Institute of Nuclear Power Operations (INPO) requested self-assessment with peer reviewers appears to have identified additional improvements and recommendations which should make for additional improvements in the outage safety plan.
Outage Safety Plan for 1R14
The DCISC Fact-finding Team met with Dennis Peterson, Director Outage Management and Jeff Knisley, Outage Manager 1R14, at the April 18-19, 2007 Fact-finding Meeting (Volume II, Exhibit D.8, Section 3.10) to review the Outage Safety Plan for 1R14.
Outage 1R14 is scheduled to start April 30, 2007. DCPP procedure AD8.ID1, "Outage Planning and Management," requires an Outage Safety Plan be written and approved for each refueling outage. The purpose of the plan is to provide information on outage safety requirements and risk areas to the plant staff. In order to assess outage safety impact, the Outage Safety Plan should be referred to prior to making major schedule changes. Industry events during refueling outages continue to show that plants are susceptible to variety of situations challenging safety during shutdown conditions..
The outage safety plan provides background information for the logic contained in the outage safety checklists. The checklists provide the logic used to develop the outage safety schedule. The outage safety schedule, along with the checklists, ensures the equipment and plant conditions assumed in the shutdown abnormal procedures are met. The shutdown abnormal procedures provide guidance for providing passive core cooling and key system restoration..
Mr. Peterson reported that the outage safety schedule review has been performed and approved by Plant Staff Review Committee (PSRC). This review verified the outage safety schedule will provide an outage schedule that maintains all the key safety functions at or above the minimum required levels for the entire outage..
Plant procedures provide an appropriate level of safety oversight. However, due to the constant changes in plant conditions, diligence must be maintained to verify key safety functions and defense in depth are assured throughout the outage. The diligence and oversight is provided by specific instructions in AD8.DC55, which require verification that the outage safety checklists will be met, to removing plant equipment from service and prior to changing plant conditions.
The 1R14 outage safety plan is similar to those in the last few outages (1R13 & 2R13). They will not be performing a hot mid-loop operation during this outage, have not performed a hot mid-loop operation in the last several outages, and will not be performing a hot mid-loop in future outages unless there is a big advantage (shorten the outage 1 to 3 days).
The 1R14 outage safety plan is about the same as the last few outages (1R13 & 2R13). DCPP will not be performing a hot mid-loop operation during this outage and will not be performing a hot mid-loop in future outages unless there is a big advantage (shorten the outage 1 to 3 days). The DCISC will continue to review the outage safety plan prior to each refueling outage.
Readiness for Restart following Refueling Outages
The DCISC Fact-finding Team met with Jeff Knisley, Outage Manager, at the May 30-31, 2007 DCISC Fact-finding Meeting (Volume II, Exhibit D.9, Section 3.7) to review the DCPP Readiness for Restart (RFR) process.
RFR is a process for determining whether all aspects of the plant are ready for the restart or mode changes and return to power following a refueling outage. The process is governed by Procedure OP1.ID1, Revision 22, dated April 12, 2006. The procedure includes personnel responsibilities and a checklist for determining readiness.
Checklists are individually tailored to each functional area. For example, the Operations Checklist includes the following:
- These areas have been inspected for any conditions that could impact a safe restart in accordance with Procedures AD4.ID1 & AD4.DC2:
- Cable Spreading Room
- Solid State Protection System
- Control Room
- Hot Shutdown Panel
- Control Room instruments and annunciators were reviewed. Components not functioning properly have been identified and evaluated for affect to Unit restart.
- The status of Control Room instruments and annunciators
- The effect of all malfunctioning components for unit restart have been evaluated and compensated for, if necessary.
- All malfunctioning components have been tagged per OP2.ID2.
- All open Prompt Operability Assessments (POAs) have been reviewed to determine if they must be resolved prior to power ascension MODE changes.
Prior to the change form Mode 4 (Hot Shutdown) to Mode 3 (Hot Standby), the Plant Staff Review Committee (PSRC) must meet and approve the readiness for change.
The DCISC Fact-finding Team reviewed the completed checklists for restart following Outage 1R14. The reviews and checklists appeared to have been executed satisfactorily. There were approximately ten mostly minor exceptions, most of which affected the transition from Mode 3 (Hot Standby) to Mode 2 (Reactor Critical). One exception dealt with leaking Turbine Lube Oil Coolers in which water was leaking into the lube oil. This was an emergent issue which was crucial for turbine operation. Using Operational Decision Making, DCPP decided to run with only one cooler and have a new tube bundle manufactured (two months) for the backup cooler. On its plant tour, the DCISC Team inspected the tube bundle. While the Team was on site, power escalation was in-progress at about 60% full power.
The DCPP Readiness for Restart Process appeared rigorous and comprehensive for determining whether the plant was fully ready to restart from a refueling outage. The completed documentation for restart from Outage 1R14 appeared satisfactory.
Outage 1R14 Results
The DCISC Fact-finding Team met with Jeff Knisley, Outage Manager, at the May 30-31, 2007 DCISC Fact-finding Meeting (Volume II, Exhibit D.9, Section 3.8) to review the results of Refueling Outage 1R14 and a preview of Outage 2R14. The DCISC also received a public meeting presentation on Outage 1R14 (Volume II, Exhibit B.9, Page B.9-34).
Outage 1R14 had a significant scope. In addition to the usual refueling operations and maintenance, the major work items were as follows:
- Containment Sump Modification
- 4kV Vital Bus “F” Hinge Wire & Cable Replacement
- Reactor Coolant system (RCS) Make-Up System Replacement
- Centrifugal Charging Pump Replacement
- Flow Accelerated Corrosion (FAC) Piping Replacement
- Main Bank Transformer Cooler Replacement
- Service Cooling Water (SCW) Chemical Cleaning
- Reactor Coolant Pump (RCP) 1-1 Ten-Year Inspection
- RCP 1-1 & 1-3 Seal Replacement
- Steam Generator Replacement Activities
Performance with respect to outage goals was as follows:
| Performance Areas | Goal | Actual |
|---|---|---|
| Nuclear Safety Events | 0 | 0 |
| Disabling Injuries | 0 | 1 |
| Recordable Injuries | 0 | 6 |
| Radiation Dose | 84 Person-Rem | 103.3 Person-Rem |
| Human Perf. Clock Resets | 0 | 1 |
| Significant FME Events | 0 | 0 |
| Outage Duration | < or = to 25 Days | 29 Days, 20 Hours |
| Power Ascension | < or = to 5 Days | 3 Days 22 Hours* |
| Safety Schedule Changes | o | 1** |
* Forecast, ** Loss of 230kV Event
This outage was the shortest ever for Unit 1 and the second shortest for either unit. The operating cycle preceding Outage 1R14 was the first time Unit 1 had no mid-cycle outages. It was the best Unit 1 Operating Capacity Factor of 100.89% (excluding 1R14) and best Capacity Factor of 95.72% (including 1R14).
Causes of outage duration overage were the Generator air test, maintenance resources unavailability, turbine lube oil cooler leaks, and Reactor Coolant Pump Seal repair. The radiation dose overage was caused by emergent work in radiation areas, RCP seal replacement, reactor cavity leak, Containment cleaning following sump work, and removal of insulation in Containment.
The DCISC Fact-finding Team believed Outage 1R14 was performed safely overall.
DCPP Outage 1R14 was performed safely with most goals being met.
Mr. Petersen reviewed the major scope items for 2R14 including:
- Steam generator replacement
- Containment fibrous material elimination and recirculation sump modification
- 10-year Integrated Containment Leak Rate Test
- Normal charging pump replacement
- RCS makeup controls upgrade
- 4 kV Bus F load cables and cubicle hinge replacement
- Service Cooling Water System chemical cleaning
- Reactor vessel head inspection
- Main generator inspection with rotor swap
The 2R14 safety plan includes no RCS "hot" mid-loop operations prior to reactor core unload. Mid-loop operations will be performed after core reload to perform RCS vacuum refill with all electrical power to be available during mid-loop. Infrequently performed tasks or evolutions during 2R14 include "cold" mid-loop operations.
The key challenges for 2R14 include maintaining excellent industrial safety and human performance, integrating other containment work scope with the Steam Generator Replacement Project including the integrated leak rate test, sump modification and fibrous material elimination, the reactor vessel head inspection, and site access issues including parking and traffic controls. DCPP’s on-site workforce will be augmented by 1,000 to 1,200 contractor personnel during 2R14.
4.17.3 Conclusions and Recommendations
- Conclusions:
- DCPP 1R14 Outage refueling outage results were good with relatively low collective personnel radiation dose and human error, and no significant nuclear safety concerns or events. DCISC will continue to review the performance of each refueling outage.
- Recommendations: None