05000346/FIN-2013005-02
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Finding | |
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| Title | Emergency Diesel Generator No. 2 Rendered Unavailable By Scheduled Maintenance |
| Description | The inspectors identified a finding of very low safety significance and an associated NCV of 10 CFR 50.65(a)(4) for the licensees failure to implement appropriate risk management actions during planned maintenance for Emergency Diesel Generator (EDG) No. 2. Specifically, field observations of the maintenance activities by the inspectors called into question the availability of EDG No. 2, which the licensee was crediting as available for at-power risk management purposes during the maintenance. Afterwards, it was identified that certain aspects of the planned maintenance activities should have resulted in the EDG being declared unavailable for a period of about an hour, and during this period the station should have entered a heightened awareness condition (yellow) for at-power risk management. The finding was determined to be of more than minor significance because it was associated with the Mitigating Systems Cornerstone of Reactor Safety and directly impacted the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, as a result of the licensee's error, EDG No. 2 was rendered unavailable without the station entering the appropriate heightened awareness condition (yellow) for at-power risk management. The inspectors evaluated the finding using IMC 0609, Appendix K, Maintenance Risk Assessment and Risk Management Significance Determination Process. Using Flowchart 1 Assessment of Risk Deficit, the inspectors determined the finding to be of very low safety significance (Green) because the difference in incremental core damage probability (ICDP), or risk deficit, at the station during the one-hour period when EDG No. 2 should have been unavailable and the station in a heightened awareness condition (yellow) for at-power risk management was much less than the threshold value of 1.0E-6 specified in Appendix K. This finding has a cross-cutting aspect in the area of human performance, work control component, because the licensee had failed to appropriately plan the EDG No. 2 work activities by incorporating applicable risk insights. (H.3(a)) |
| Site: | Davis Besse  |
|---|---|
| Report | IR 05000346/2013005 Section 1R13 |
| Date counted | Dec 31, 2013 (2013Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.13 |
| Inspectors (proximate) | C Moore D Kimble J Cameron J Laughlin J Neurauter M Bielby M Marshfield M Mitchell T Briley |
| Violation of: | 10 CFR 50.65(a)(4) 10 CFR 50.65 |
| CCA | H.5, Work Management |
| INPO aspect | WP.1 |
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Finding - Davis Besse - IR 05000346/2013005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Davis Besse) @ 2013Q4
Self-Identified List (Davis Besse)
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