05000482/FIN-2013008-11
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Finding | |
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Title | Failure to Verify Adequacy of Electrical Protective Devices to Isolate Fire-Damaged Associated Circuits |
Description | The team identified a Green, non-cited violation of 10 CFR 50, Appendix B, Criterion III, Design Control, which states, in part, Measures shall be established to assure that applicable regulatory requirements and the design basis are correctly translated into specifications, drawings, procedures, and instructions. The design control measures shall provide for verifying or checking the adequacy of design, such as by the performance of design reviews, by the use of alternate or simplified calculational methods, or by the performance of a suitable testing program. Specifically, as of September 2011, Wolf Creek Updated Safety Analysis Report, Appendix 9.5 E, required isolation between safe shutdown circuits and non-safe shutdown (associated) circuits, such that hot shorts, open circuits, or shorts to ground in the associated circuits will not prevent operation of the safe shutdown equipment. On September 29, 2011, the licensee completed study WCNOC-171, Post-Fire Safe Shutdown Associated Circuits Study, Revision 0, but failed to provide documented verification of the adequacy of electrical protective devices for associated shutdown circuits such that hot shorts or shorts to ground will not prevent operation of the safe shutdown equipment. The licensee has entered this issue into their corrective action program as Condition Report CR-73242. The team determined that the licensees failure to provide a documented comparison of upstream and downstream electrical protective devices with maximum short circuit levels, in order to verify the required coordination, was a performance deficiency. This finding was more than minor because it was associated with the Design Control attribute of the Reactor Safety, Mitigating Systems Cornerstone, and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the licensee was unable to provide an analysis to demonstrate that associated shutdown circuits would be isolated from the safe shutdown circuits during fire events. In accordance with NRC Inspection Manual Chapter 0609, Appendix A, Exhibit 2, the inspectors determined the finding was of very low safety significance (Green), because the finding was not a design deficiency and did not result in the loss of operability or functionality. The finding had a cross-cutting aspect in the area of Human Performance, Resources attribute, because the licensee failed to ensure that personnel, equipment, procedures, and other resources are adequate to assure nuclear safety by maintaining long-term plant safety by maintenance of design margins. |
Site: | Wolf Creek |
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Report | IR 05000482/2013008 Section 1R21 |
Date counted | Sep 30, 2013 (2013Q3) |
Type: | NCV: Green |
cornerstone | Mitigating Systems |
Identified by: | NRC identified |
Inspection Procedure: | IP 71111.21 |
Inspectors (proximate) | S Garchow B Correll A Sengupta H Leake R Kopriva T Farnholtz |
Violation of: | 10 CFR 50 Appendix B Criterion III, Design Control |
CCA | H.6, Design Margins |
INPO aspect | WP.2 |
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Finding - Wolf Creek - IR 05000482/2013008 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Wolf Creek) @ 2013Q3
Self-Identified List (Wolf Creek)
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