05000482/FIN-2011005-01
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Finding | |
|---|---|
| Title | Failure to Evaluate Gasket Capability |
| Description | The inspectors reviewed a self-revealing, non-cited violation of 10 CFR Part 50, Appendix B, Criterion III, Design Control, associated with an improperly selected essential service water gasket that sprayed safety-related electrical equipment. On August 31, 2011, essential service water pump A was started and a 1 gpm leak from a bolted flange on the strainer was observed spraying a Class 1E supply transformer. The gasket was found to be broken due to excessive torque, and was replaced. Wolf Creeks apparent cause evaluation concluded that the cause of the gasket failure was not evaluating the suitability of existing gasket material to be used in conjunction with the new, hard Ceramalloy coating applied to the strainers as part of a design change in 2003. The strainer joints had been previously re-tightened to stop leakage without evaluating the cause. Selecting inappropriate gasket material, which led to repeated leaks and tightening until the gasket broke, was a performance deficiency. The performance deficiency is more than minor because it could be a precursor to a loss of essential service water event. Specifically, the water spray was wetting a transformer that could have cause the loss of the train A traveling screen, strainer, and ventilation. The inspectors used Inspection Manual Chapter 0609.04, and determined the issue was Green, or very low safety significance, because assuming worst case degradation, the finding did not affect train B. Also, train A essential service water was inoperable for less than its allowed outage time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> because it was successfully run the previous day. The finding had a cross-cutting aspect in the area of problem identification and resolution because Wolf Creek did not thoroughly evaluate the problem such that the resolutions address causes and extent of conditions, as necessary. Specifically the bolted flanges of the essential service water strainer A had leaked multiple times over the past 2 years, but did not get evaluated because they were classified as find and fix. |
| Site: | Wolf Creek  |
|---|---|
| Report | IR 05000482/2011005 Section 1R12 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | NCV: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.12 |
| Inspectors (proximate) | R Deese G Guerra P Elkmann L Willoughby N O'Keefe C Long C Peabody C Steely D Strickland N Makris |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - Wolf Creek - IR 05000482/2011005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Wolf Creek) @ 2011Q4
Self-Identified List (Wolf Creek)
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