05000445/FIN-2011006-04
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Finding | |
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| Title | Repeated Diesel Generator Cam Cover Bolt Failures |
| Description | The team identified a Green noncited violation of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, in that the licensee did not correct a condition adverse to quality regarding the safety related diesel generators. Specifically, as of July 12, 2011, the licensee failed to assure that the identified broken cam cover bolts on the diesel generators were adequately corrected. The licensee entered the finding into the corrective action program as Condition Report CR 2011-008505. The performance deficiency was determined to be more than minor because it was associated with the equipment performance attribute of the Mitigating System Cornerstone and affects the cornerstone objective to ensure the availability and reliability of safety related diesel generators that respond to initiating events to prevent undesirable consequences in that the safety related diesel generators supply power to vital and safety related loads. Because Manual Chapter 0609, Attachment 4, Phase 1 Initial Screening and Characterization of Findings, was not well suited for this finding a Phase 3 Risk Significance Estimation was required. A Region IV senior reactor analyst performed a bounding Phase 3 significance determination and found that the finding was of very low safety significance. The bounding change to core damage frequency was 6.7E-7/year. The SPAR model does not include the contribution of the recently installed alternate power generators, which would considerably lower the risk significance of safety related diesel generator failure for the station blackout sequences, which comprise most of the risk of this finding. The team determined that there was a crosscutting aspect in the area of problem identification and resolution because the licensee failed to thoroughly evaluate problems such that the resolutions address causes and extent of conditions, as necessary. |
| Site: | Comanche Peak  |
|---|---|
| Report | IR 05000445/2011006 Section 4OA2 |
| Date counted | Sep 30, 2011 (2011Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | J Reynoso W Sifre J Kramer J Braisted D Powers |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - Comanche Peak - IR 05000445/2011006 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Comanche Peak) @ 2011Q3
Self-Identified List (Comanche Peak)
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