05000461/FIN-2012004-01
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Finding | |
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| Title | Failure to Correctly Assemble Diesel Generator Ventilation System Damper Resulted in Inoperable Diesel Generator |
| Description | A finding of very low safety significance with an associated non-cited violation of 10 CFR 50, Appendix B, Criteria V, Instructions, Procedures, and Drawings was self-revealed on March 1, 2012 when the Division 1 diesel generator (DG) ventilation system supply damper was discovered failed closed with the ventilation supply fan running during a Division 1 DG surveillance test. The damper failure occurred due to the licensees failure to establish an adequate procedure to perform maintenance. Specifically, the maintenance procedure did not contain an appropriate verification step to ensure that locknuts on the damper hydramotor coupling were tightly fastened. As a result, vibration of the coupling during operation over time caused the coupling to separate such that the damper would not open. The licensee entered this issue into its corrective action program for evaluation, repaired the damper, and initiated corrective actions to revise the maintenance procedure. The finding was of more than minor significance since it was associated with the Procedure Quality attribute and adversely affected the Mitigating Systems Cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, the damper failure rendered the Division 1 DG inoperable. Although the finding involved an actual loss of function of a single train for greater than its Technical Specification allowed outage time, it was determined to be of very low safety significance during a detailed quantitative Significance Determination Process review since the delta core damage frequency and delta large early release frequency were both determined to be negligible based upon crediting operator recovery actions to restore DG room ventilation. The inspectors concluded that this finding affected the cross-cutting area of human performance since adequate licensee resources involving personnel and procedures did not support successful human performance. Specifically, the maintenance procedure did not contain adequate instructions to ensure that locknuts on the damper hydramotor coupling were tightly fastened. |
| Site: | Clinton  |
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| Report | IR 05000461/2012004 Section 1R15 |
| Date counted | Sep 30, 2012 (2012Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | B Kemker D Lords D Passehl J Beavers J Bozga J Draper M Ring R Ruiz S Mischkea Shaikhb Kemker B Orlikowski D Lords D Reeser J Draper J Laughlin S Mischke V Myers |
| CCA | H.13, Consistent Process |
| INPO aspect | DM.1 |
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Finding - Clinton - IR 05000461/2012004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Clinton) @ 2012Q3
Self-Identified List (Clinton)
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