05000382/FIN-2014008-02
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Finding | |
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Title | Failure to Identify and Correct Condition Adversely Affecting Flooding Mitigation Design |
Description | The team identified a non-cited violation of 10 CFR Part 50, Appendix B, Criterion XVI, for the licensees failure to identify and correct a condition adverse to quality. On May 19, 2014, the team identified a significant amount of debris on the floor of one of the main steam isolation valve areas. In a probable maximum precipitation event, this debris could have prevented sufficient water removal by the floor drains to meet design basis assumptions. Following identification, the licensee entered this condition into its corrective action program as Condition Report CR-WF3-2014-03037 and removed the debris from the area. Excessive debris in the main steam isolation valve A area that could challenge the water removal capability of safety-related drain systems was a condition adverse to quality. The licensees failure to promptly identify and correct this condition adverse to quality as required by 10 CFR Part 50, Appendix B, Criterion XVI was a performance deficiency. This performance deficiency was more than minor because if left uncorrected, it had the potential to lead to a more significant safety concern. The lead inspector performed the initial significance determination for performance deficiency using NRC Inspection Manual 0609, Appendix A, Exhibit 4, External Events Screening Questions, dated July 1, 2012. The finding required a detailed risk evaluation because it involved the degradation of equipment specifically designed to mitigate a flooding event. Therefore, a Region IV senior reactor analyst performed a bounding detailed risk evaluation. The bounding change to the core damage frequency was 4.7x10-8 per year (Green). The dominant core damage sequences included extremely heavy rainfall, a loss of offsite power initiating event, failure of the train B 4.16kV bus, and failure of the pressurizer safety relief valves to close. The low initiating event frequency reduced the risk significance. This finding has a resolution cross-cutting aspect in the problem identification and resolution cross-cutting area because the licensee failed to take effective corrective actions to address issues in a timely manner commensurate with their safety significance. Specifically, the licensees corrective actions from the previous non-cited violation did not fully address the issue (P.3). |
Site: | Waterford ![]() |
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Report | IR 05000382/2014008 Section 4OA2 |
Date counted | Jun 30, 2014 (2014Q2) |
Type: | NCV: Green |
cornerstone | Mitigating Systems |
Identified by: | NRC identified |
Inspection Procedure: | IP 71152 |
Inspectors (proximate) | G Miller P Jayroe S Crane A Sanchez C Speer E Ruesch |
Violation of: | 10 CFR 50 Appendix B Criterion XVI |
CCA | P.3, Resolution |
INPO aspect | PI.3 |
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Finding - Waterford - IR 05000382/2014008 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Waterford) @ 2014Q2
Self-Identified List (Waterford)
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