05000305/FIN-2011003-01
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Finding | |
|---|---|
| Title | Technical Support Center Diesel Generator Output Breaker Fails to Close |
| Description | A finding of very low safety significance was self-revealed for the failure to perform adequate preventive maintenance on latching relay VR1/B46, a relay required for closure of the Technical Support Center (TSC) diesel generators (DGs) output breaker and automatic restoration of bus 1-46, which powers the TSC DGs cooling system. Specifically, on March 20, 2011, during a partial loss of offsite power event, the TSC DG started but failed to load onto bus 1-46. After approximately 43 minutes of operation, the DG automatically shut down from an over-temperature condition, as designed. The licensee initiated condition report 417289 and performed apparent cause evaluation 018573. The licensees short-term corrective actions included troubleshooting the initial failure, repairing relay VR1/B46, and restoring the TSC DG to functional status. The licensees long-term corrective actions were in-progress at the completion of this inspection period. The finding was determined to be more than minor because the finding was associated with the Mitigating Systems Cornerstone attribute of equipment performance and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the failure of the output breaker to close and energize bus 1-46 caused the TSC DG to overheat and automatically shut down during a partial loss of offsite power. The inspectors concluded the finding could be evaluated in accordance with IMC 0609, Significance Determination Process, Attachment 0609.04, Phase 1 - Initial Screening and Characterization of Findings, Table 4a, for the Mitigating Systems Cornerstone. The inspectors answered Yes to questions 2 and 4 of the Mitigating Systems Cornerstone column and determined that the finding required a Phase 2 analysis. The Region III senior reactor analyst completed a Phase 2 analysis and determined the risk significance of the issue to be very low (Green). The finding has a cross-cutting aspect in the area of human performance, resources, because a licensee effort to review various plant components for possible inclusion in a preventive maintenance optimization project had assigned a low priority to this relay (H.2(a)). |
| Site: | Kewaunee  |
|---|---|
| Report | IR 05000305/2011003 Section 1R12 |
| Date counted | Jun 30, 2011 (2011Q2) |
| Type: | Finding: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.12 |
| Inspectors (proximate) | R Winter J Cassidy M Kunowski R Krsek K Barclay K Carrington |
| CCA | H.6, Design Margins |
| INPO aspect | WP.2 |
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Finding - Kewaunee - IR 05000305/2011003 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Kewaunee) @ 2011Q2
Self-Identified List (Kewaunee)
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