05000334/FIN-2015007-01
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Finding | |
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| Title | Unanlayzed Condition Resulting from Unfused Direct Current Control Circuits |
| Description | On April 30, 2014, FENOC identified a violation of very low safety significance of 10 CFR 50, Appendix R, Section III.G for BVPS Unit 1 in that unfused direct current (DC) control circuits for DC motors were routed from the turbine building through other fire areas. The DC breakers used to protect the motor power conductors were insufficient to protect the control conductors for these circuits and it is postulated that a fire induced short in one fire area could adversely impact safe shutdown equipment by overheating the cable and causing a secondary fire in other fire areas where the cable is routed. The team identified that FENOC did not establish a fire watch in one of the affected fire areas, the turbine building, as a compensatory measure. Therefore, because FENOC did not initiate immediate corrective action or compensatory measures or both within a reasonable time, enforcement discretion will not be exercised. This violation will be treated as a NRC-identified violation. In response to the NRC finding, FENOC promptly initiated a one hour roving fire watch patrol in the turbine building. The lack of compensatory measures in the turbine building occurred because administrative procedure, 1/2-ADM-1900, Fire Protection Program, used to determine compensatory measures for fire protection program deficiencies, was inadequate in its guidance to plant personnel for review of cable separation issues. For cable separation issues, 1/2-ADM-1900 required fire watches in only one of two affected adjacent fire areas. FENOC entered this issue into its corrective action program as condition report (CR) CR-2015-10546 and planned to revise 1/2-ADM-1900 to ensure fire watches were established in all affected fire areas that involved cable separation issues. FENOC initiated CR-2014-07961 to resolve the DC circuit non-conformance using National Fire Protection Association (NFPA) 805 performance based fire risk evaluations considering the low probability of a secondary cable fire due to overheating of cables associated with the pump motor control circuits during an electrical fault condition with no circuit protection. This finding was more than minor because it adversely affected the protection against external factors (i.e., fire) attribute of the Mitigating Systems Cornerstone and affected the cornerstone objective of ensuring the availability and reliability of systems that respond to initiating events to prevent undesirable consequences. FENOC reviewed the cable routes and evaluated this issue through use of its fire probabilistic risk assessment (PRA). FENOC determined that the change in core damage frequency attributed to the issue for Unit 1 was 8.5E-7 per reactor year. NRC staff reviewed this evaluation and concluded that the risk numbers were bounded by conservative assumptions and that this issue would be of very low safety significance. This finding had a cross-cutting aspect in the area of Human Performance, Resources, because FENOC did not ensure that procedures were adequate to support nuclear safety. Specifically, 1/2-1900-ADM was too restrictive for safe shutdown circuit separation issues in that it mandated an hourly fire watch patrol in only one of the two adjacent fire areas and for this issue FENOC did not appropriately establish an hourly fire watch patrol in the Unit 1 turbine building. [H.1] |
| Site: | Beaver Valley |
|---|---|
| Report | IR 05000334/2015007 Section 1R05 |
| Date counted | Sep 30, 2015 (2015Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.05 |
| Inspectors (proximate) | C Cahill D Orr J Patel J Rady J Rogge S Galbreath |
| Violation of: | 10 CFR 50 Appendix R 10 CFR 50 Appendix R Section III.G |
| CCA | H.1, Resources |
| INPO aspect | LA.1 |
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Finding - Beaver Valley - IR 05000334/2015007 | |||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Beaver Valley) @ 2015Q3
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