05000454/FIN-2017007-02
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Finding | |
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Title | Failure to Promptly Identify Degraded Reactor Containment Fan Cooler Circuitry |
Description | The inspectors identified a finding of very low safety significance and an associated NCV of Title 10 of the Code of Federal Regulations (CFR), Part 50, Appendix B, Criterion XVI, Corrective Action, when the licensee failed to promptly identify a condition adverse to quality resulting in a safety -related system becoming inoperable. Specifically, from May 5, 2017, to August 4, 2017, the licensee failed to trend available surveillance data in a timely manner and did not identify a degraded condition in the 1A reactor containment fan cooler (RCFC) time delay circuitry prior to the system becoming inoperable. The licensee entered this issue into their CAP as AR 04039037 and AR 04045767, replaced the failed relay, and planned to update the RCFC system monitoring plan to note abnormal changes in time delay relay actuation times and improve coordination between engineering and operations to reduce the time it takes engineering to obtain RCFC surveillance data for trending after surveillances are completed. The inspectors determined that the failure to promptly identify a condition adverse to quality associated with the time delay relay circuitry in the 1A RCFC was a performance deficiency. The performance deficiency was more than minor because it was associated with the Mitigating Systems cornerstone attribute of Equipment Performance and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the failure to identify a degraded condition in the time delay circuitry associated with the 1A RCFC resulted i n a missed opportunity for the licensee to evaluate the cause and initiate prompt actions to respond to the degraded condition prior to the failure. The inspectors answered No to questions A.1 through A.4 of IMC 0609, Appendix A, The Significance Determination Process for Findings At -Power, Exhibit 2, Mitigating Systems Screening Questions ; therefore, the finding screened as 4 having very low safety significance. This finding affected the Cross -Cutting area of Problem Identification and Resolution in the aspect of Trending because information was available that indicated a degraded condition in the 1A RCFC time delay relay circuitry for three months prior its failure in August , but was not identified and evaluated by the licensee prior to failure [P.4] . |
Site: | Byron ![]() |
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Report | IR 05000454/2017007 Section 4OA2 |
Date counted | Sep 30, 2017 (2017Q3) |
Type: | NCV: Green |
cornerstone | Mitigating Systems |
Identified by: | NRC identified |
Inspection Procedure: | IP 71152 |
Inspectors (proximate) | R Ng C Hunt C Norton A Dunlop G Edwards C Thompson E Duncan |
Violation of: | 10 CFR 50 Appendix B 10 CFR 50 Appendix B Criterion XVI |
CCA | P.4, Trending |
INPO aspect | PI.4 |
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Finding - Byron - IR 05000454/2017007 | |||||||||||||||||||||||||||||||||||
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Finding List (Byron) @ 2017Q3
Self-Identified List (Byron)
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