05000390/FIN-2012009-04
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Finding | |
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| Title | Failure to Adequately Protect SAFETY-RELATED Equipment During Flood Mode Preparation |
| Description | The inspectors identified an AV of 10 CFR 50, Appendix B, Criterion III, Design Control, for the licenseefs failure to adequately protect safety-related equipment during flood mode preparation. The licenseefs failure to adequately protect safety-related equipment during flood mode preparation as implemented by AOI-7.1, Maximum Probable Flood, was a performance deficiency. This performance deficiency was considered more than minor because it was associated with the Protection Against External Factors attribute of the Reactor Safety/Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, the TACF was incapable of preventing water damage, during a PMF event, to both trains of important equipment, specifically the thermal barrier booster pumps (TBBPs), necessary for coping with the PMF impact on Unit 1. Without the TBBPs and with reactor coolant pump (RCP) seal injection lost, there is no engineering assurance that RCP seal damage would not occur, leading to an RCP seal loss of coolant accident (LOCA). The performance deficiency involved external events. Consequently a Phase 2 analysis could not be performed and therefore a Phase 3 analysis was conducted. The increase in core damage frequency (CDF) for this issue was estimated at 6.35~10-6; which has an impact of low to moderate safety significance. The NRC concluded that the significance of the finding is preliminarily of low to moderate safety significance (White). This finding has a cross-cutting aspect in the Work Practices component of the Human Performance area because it was directly related to the licensee not ensuring adequate supervisory and management oversight of engineering design work activities associated with a plant design change to protect the TBBPs during certain flood events. |
| Site: | Watts Bar  |
|---|---|
| Report | IR 05000390/2012009 Section 1R01 |
| Date counted | Mar 31, 2013 (2013Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.01 |
| Inspectors (proximate) | K Miller R Monk S Shaeffer |
| Violation of: | 10 CFR 50 Appendix B Criterion III, Design Control |
| CCA | H.2, Field Presence |
| INPO aspect | LA.2 |
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Finding - Watts Bar - IR 05000390/2012009 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Watts Bar) @ 2013Q1
Self-Identified List (Watts Bar)
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