05000271/FIN-2014007-01
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Finding | |
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| Title | Inadequate Design Control of SBO Loading Calculation |
| Description | The team identified a finding of very low safety significance (Green), in that Entergy did not ensure correct implementation of their design control process when establishing the capacity requirement for the new Station Blackout (SBO) alternate alternating current (AAC) power source. Specifically, Entergy did not use the latest revision of the SBO load capacity analysis as a design input to the load capacity requirement when verifying the adequacy of the sizing of the new SBO diesel generator (DG). Entergy entered the issue into their corrective action system to evaluate the capability of the SBO DG to support the expected SBO loads and initiated actions to ensure the design analysis assumptions for loading are consistent with the established operational procedures for SBO response. The finding is more than minor because it is associated with the design control attribute of the Mitigating Systems cornerstone and affected the cornerstone objective of ensuring the capability of systems that respond to initiating events to prevent undesirable consequences. In addition, inspectors reviewed IMC 0612, Appendix E, Examples of Minor Issues, and found that example 3.j was similar, in that, the team had reasonable doubt of the capability of the SBO DG to operate within its analyzed load rating. Specifically, the most limiting condition with residual heat removal service water (RHRSW) pumps in service had not been accounted for in the SBO DG load rating evaluation. In accordance with IMC 0609.04, Initial Characterization of Findings, and Exhibit 2 of IMC 0609, Mitigating Systems Screening Questions, Section A, Mitigating SSCs and Functionality, the team concluded that this finding was a design deficiency that did not result in the SBO DG losing its functionality. Specifically, the team evaluated decay heat level requirements and determined there was reasonable assurance the SBO DG load would have remained within its design rating. The team determined that this finding had a cross-cutting aspect in the area of Human Performance, Procedure Adherence, because the design control engineering change process procedure was not adequately followed, in that, the increased SBO load associated with a second RHRSW pump was not evaluated and resolved through the design review process. |
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
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| Report | IR 05000271/2014007 Section 1R21 |
| Date counted | Jun 30, 2014 (2014Q2) |
| Type: | Finding: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | J Patel J Schoppy M Orr P Krohn F Arner G Gardner |
| CCA | H.8, Procedure Adherence |
| INPO aspect | WP.4 |
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Finding - Vermont Yankee - IR 05000271/2014007 | |||||||||||||||||||||||||||||||||||||||||
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Finding List (Vermont Yankee) @ 2014Q2
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