05000482/FIN-2009004-03
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Finding | |
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Title | Inadequate Evaluation of Emergency Diesel Generator for Common Cause Failure in the Supporting Essential Service Water System |
Description | On June 30, 2009, the inspectors identified a noncited violation of Technical Specification 3.8.1 for failure to perform an adequate common cause evaluation within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to demonstrate no common cause failure mechanism existed between the emergency diesel generators after a through-wall leak was discovered on the essential service water piping. Wolf Creek did not start the opposite train emergency diesel generator and declared that the through-wall flaw was not a common cause failure without any evaluation or supporting statements. Nondestructive testing had not been started at this time. Subsequent evaluation of the flaw per American Society of Mechanical Engineers (ASME) Code Case N513.2 restored operability to the essential service water piping. The licensee entered this issue in their corrective action program as Condition Report 18347. The inspectors determined that the failure to demonstrate, per Technical Specifications 3.8.1 Required Actions B.3.1 or B.3.2, that no common cause failure existed for the emergency diesel generators was a performance deficiency. The inspectors determined that this finding was more than minor because it is associated with the equipment performance attribute for the Mitigating Systems Cornerstone and affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The inspectors evaluated the significance of this finding using Phase 1 of Inspection Manual Chapter 0609, Appendix A, Significance Determination of Reactor Inspection Findings for At Power Situations, and determined that the finding was of very low safety significance (Green) because the issue was not a design or qualification deficiency confirmed to result in loss of operability or functionality, did not represent a loss of system safety function, an actual loss of safety function of a single train for greater than its technical specification allowed outage time, an actual loss of safety function of a nontechnical specification risk-significant equipment train, and did not screen as potentially risk significant due to a seismic, flooding, or severe weather initiating event. The cause of the finding has a problem identification and resolution crosscutting aspect in the area associated with the corrective action program because Wolf Creek failed to thoroughly evaluate the failure mechanism such that the resolutions address the causes and extent of conditions, as necessary. Specifically Wolf Creek did not properly consider the possibility of common-cause pitting failures which could have impacted the essential service water piping Train A structural integrity thereby affecting its cooling loads, including the Emergency Diesel Generator A P.1(c) |
Site: | Wolf Creek |
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Report | IR 05000482/2009004 Section 1R15 |
Date counted | Sep 30, 2009 (2009Q3) |
Type: | NCV: Green |
cornerstone | Mitigating Systems |
Identified by: | NRC identified |
Inspection Procedure: | IP 71111.15 |
Inspectors (proximate) | C Long C Peabody C Ryan G Apger G Miller G Tutak J Adams P Jayroe S Alferinkc Longc Peabody G Miller G Werner M Shannon N O'Keefe P Jayroe R Kellar S Garchow |
CCA | P.2, Evaluation |
INPO aspect | PI.2 |
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Finding - Wolf Creek - IR 05000482/2009004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Wolf Creek) @ 2009Q3
Self-Identified List (Wolf Creek)
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