05000482/FIN-2011007-03
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Finding | |
|---|---|
| Title | Failure to Ensure Post-Fire Safe Shutdown Components Remain Free of Fire Damage |
| Description | The team identified a non-cited violation of License Condition 2.C(5) because the licensee failed to implement and maintain in effect all provisions of the approved fire protection program. Specifically, the licensee failed to properly analyze for fire damage in the form of shorts-to-ground related to the residual heat removal Train B refueling water storage tank suction valve and the pressurizer power-operated relief valves. Certain postulated shorts-to-ground could spuriously actuate these valves such that safe shutdown would be impacted. The licensee documented these deficiencies in Condition Reports 044912 and 045452, respectively. The failure to protect the residual heat removal Train B suction cables and the pressurizer power operated relief valve cables against all modes of cable failure during post-fire safe shutdown circuit analysis was a performance deficiency. The performance deficiency was more than minor because it was associated with the design control attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The team used Manual Chapter 0609, Appendix F, Fire Protection Significance Determination Process, because the performance deficiency affected fire protection defense-in-depth strategies involving post-fire safe shutdown. The team categorized the finding as having a high degradation rating because the post-fire safe shutdown analysis was not complete. Because the Phase 1 screening criteria were not met, the team performed a Phase 2 analysis. The team walked down the affected fire area for each example as part of the Phase 2 quantitative screening. The team identified fire ignition sources and targets, and specific fire growth and damage scenario combinations for each example. The sum of the conditional core damage frequencies for the fire scenarios was 5.15E-7/year, which bounded the total change in core damage frequency associated with this performance deficiency. This performance deficiency had a cross-cutting aspect in the area of human performance associated with decision making because the licensee did not use conservative assumptions during their design review process. Specifically, the licensee did not follow industry guidance related to performing a circuit analysis |
| Site: | Wolf Creek  |
|---|---|
| Report | IR 05000482/2011007 Section 1R05 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.05 |
| Inspectors (proximate) | G Pick G Miller S Alferink J Mateychick B Correll |
| INPO aspect | |
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Finding - Wolf Creek - IR 05000482/2011007 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Wolf Creek) @ 2011Q4
Self-Identified List (Wolf Creek)
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