05000458/FIN-2014002-04
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Finding | |
|---|---|
| Title | Failure to Promptly Correct a Degraded Emergency Diesel Generator Voltage Regulator |
| Description | The inspectors identified a non-cited violation of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, for failure to promptly correct a degraded voltage regulator in the Division 3 emergency diesel generator. Specifically, the station failed to use operating experience in a timely manner, which resulted in the lockout of the Division 3 emergency diesel generator output breaker. The station replaced the voltage regulator to correct this condition. The licensee entered this issue into their corrective action program as Condition Report CR-RBS-2013-06789. The inspectors determined that the failure of the licensee to promptly correct the cause of erratic KVAR/voltage output from the Division 3 emergency diesel generator is a performance deficiency. The performance deficiency is more than minor, and therefore a finding, because it is associated with the Mitigating Systems Cornerstone attribute of equipment performance and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). The inspectors used the NRC Inspection Manual 0609, Appendix A, Exhibit 2, Mitigating Systems Screening Questions. The finding required a detailed risk evaluation because it involved a potential loss of one train of safety-related equipment for longer than the technical specification allowed outage time. The total exposure period was 20.3 days. The allowed outage time was 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The analyst determined the change to the core damage frequency was 1.6E-7/year (Green). The finding was of very low safety significance (Green). The dominant core damage sequences included loss of offsite power events leading to station blackout. Equipment that helped mitigate the risk included recovery of an emergency diesel generator or offsite power. The finding was not a significant contributor to the large early release frequency (LERF). The cause of the performance deficiency appeared to be the ineffective use of industry operating experience. Therefore, the finding had a cross-cutting aspect in the area of problem identification and resolution, associated with the operating experience component because the licensee failed to systematically and effectively collect, evaluate, and implement relevant internal and external operating experience in a timely manner. |
| Site: | River Bend  |
|---|---|
| Report | IR 05000458/2014002 Section 4OA2 |
| Date counted | Mar 31, 2014 (2014Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | R Kopriva T Skaggs Ryan A Barrett D Allen G Larkin J O'Donnell L Ricketson |
| Violation of: | 10 CFR 50 Appendix B Criterion XVI Technical Specification |
| CCA | P.5, Operating Experience |
| INPO aspect | CL.1 |
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Finding - River Bend - IR 05000458/2014002 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (River Bend) @ 2014Q1
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