05000455/FIN-2014005-04
Finding | |
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| Title | Failure to Evaluate Operability of a TS SSC Upon Discovery of a Support System Degraded Condition |
| Description | Inspectors identified a finding of very low safety significance and associated NCV of 10 CFR Part 50, Appendix B, Criterion V, Instructions Procedures, and Drawings, for failure to implement procedure OP-AA-108-115, Operability Determinations (CM-1), as written when a degraded condition was identified for a non-TS SSC that supported a TS SSC. Specifically, during a surveillance test of the flood barrier door to the 2B emergency diesel generator (EDG) fuel oil storage tank room in March 2014, maintenance technicians identified a degraded condition that, while not affecting immediate functionality of the barrier, was identified to have the potential to impact the door functionality prior to the next scheduled performance of the surveillance. An Operability Determination was not performed for the supported TS SSCs at that time as required by OPAA108115 and in June of 2014 (the next surveillanc
performance), the door failed the test, and both Unit EDGs were declared inoperable. The issue was entered in the CAP as Issue Report (IR) 1675255. Upon discovery of the failure of the water-tight door, a temporary water-tight barrier was immediately installed, restoring operability of the Unit 2 EDGs. The permanent water-tight door was repaired and returned to service at a later date. Failure to perform and document an operability determination of the Unit 2 EDGs and fuel oil transfer pumps upon discovery of the degraded condition of the support system (i.e., flood barrier door) is a performance deficiency. The finding was more than minor because, if left uncorrected, failure to evaluate operability through a SSCs surveillance interval can lead to more significant safety concerns and an unevaluated assumption o risk by the station. The finding affected the Mitigating Systems Cornerstone because it impacted an External Events Mitigation System (degraded flood protection). Because a complete loss of the water-tight door could impact both Unit 2 EDG trains, the NRC Senior Reactor Analysts (SRAs) performed a more detailed significance determination and determined that the finding was not greater than Green. The finding had a cross-cutting aspect of Conservative Bias in the area of Human Performance (IMC 0310 H.14) because the licensees decisions regarding disposition of the degraded condition did not indicate a conservative bias that emphasized prudent choices over those that were allowable. Even though mechanics identified the potential for the condition to degrade further in the near future, the work request was not given a high priority and continued functionality of the door was not evaluated through the nex surveillance period by the licensee. |
| Site: | Byron  |
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| Report | IR 05000455/2014005 Section 1R15 |
| Date counted | Dec 31, 2014 (2014Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | C Thompson J Cassidy J Draper J Ellegood J Mcghee M Bielby M Holmberg R Baker R Jickling T Bilik |
| Violation of: | 10 CFR 50 Appendix B Criterion V Technical Specification Technical Specification - Procedures |
| CCA | H.14, Conservative Bias |
| INPO aspect | DM.2 |
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Finding - Byron - IR 05000455/2014005 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Byron) @ 2014Q4
Self-Identified List (Byron)
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