05000305/FIN-2013002-02
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Finding | |
|---|---|
| Title | Inadequate Risk Assessment for Degraded Equipment |
| Description | The inspectors identified a finding of very low safety significance and associated non-citied violation of 10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, Paragraph (a)(4), for the failure to properly assess the risk during scheduled testing of EDG B, on February 25. Specifically, the licensee failed to update the risk model after identifying that the manual bypass switch (MBS) for BRD-109, a risk-significant inverter, was not functioning properly. On February 13, 2013, the licensee identified that the MBS for the output of BRD-109 was broken, and BRD-109 was not powering BRD-115, a non-interruptible bus, even though the Normal position was selected. The licensee did not include the alternate switch position in the risk model until prompted by the NRC inspectors on February 26. This resulted in the risk from the EDG B testing being incorrectly assessed as green, when it was actually yellow. The licensee entered the issue into the corrective action program (CAP) and assigned an apparent cause evaluation (ACE) to determine the causes for the organizational failures that occurred. The ACE was not yet complete at the end of this inspection period, The inspectors determined that the failure to properly assess risk was a performance deficiency. The finding was determined to be more than minor because it was associated with the Mitigating Systems Cornerstone attribute of Human Performance, and adversely affected the Cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). The inspectors evaluated this finding using the worksheets from IMC 0609, Appendix K, Maintenance Risk Assessment and Risk Management Significance Determination Process, dated May 19, 2005, because the finding is a maintenance risk assessment issue. Flowchart 1, Assessment of Risk Deficit, requires the inspectors to determine the risk deficit associated with this issue. This finding was determined to be of very low safety significance because the incremental core damage probability deficit was less than 1 x 10-6. This finding has a cross-cutting aspect in the area of problem identification, corrective action program, because the licensee did not ensure that issues potentially impacting nuclear safety are promptly identified, fully evaluated, and that actions were taken to address safety issues in a timely manner, commensurate with their significance. |
| Site: | Kewaunee  |
|---|---|
| Report | IR 05000305/2013002 Section 1R13 |
| Date counted | Mar 31, 2013 (2013Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.13 |
| Inspectors (proximate) | K Riemer D Szwarc R Krsek K Barclay V Myers M Ziolkowski |
| Violation of: | 10 CFR 50.65 |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - Kewaunee - IR 05000305/2013002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Kewaunee) @ 2013Q1
Self-Identified List (Kewaunee)
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