05000259/FIN-2012004-02
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Finding | |
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Title | Automatic Reactor Scram Due to Inadequate Design Review of Relay Setting |
Description | A self-revealing finding (FIN) was identified for the licensees failure to provide an adequate design review of vendor calculations as required by TVA-NQAPLN89- A, Nuclear Quality Assurance Plan which resulted in the 3A Unit Station Service Transformer (USST) differential current protection relay trip settings being incorrectly set. The licensee reset and adequately tested the function of the relay. The licensee has evaluated vendor-provided modifications for similar protective relays and plans to revise the design review process to provide increased licensee accountability and specificity of reviews for vendor designs. The licensee entered this issue into their corrective action program as problem evaluation report (PER) 555573. This finding was determined to be more than minor because it was associated with the Design Control attribute of the Initiating Events cornerstone and adversely affected the cornerstone objective to limit the likelihood of those events that upset plant stability. Specifically, the failure to provide an adequate design review of vendor calculations directly contributed to a reactor scram of Unit 3. The significance of the finding was evaluated using Phase 1 of the Significance Determination Process (SDP) in accordance with Inspection Manual Chapter 0609 Attachment 4 and Appendix A and was determined to be of very low safety significance (Green) because it did not contribute to both the likelihood of a reactor trip and the likelihood that mitigating equipment or functions were not available. The cause of this finding was directly related to the cross-cutting aspect of Complete Documentation in the Resources component of the Human Performance area, because the licensee failed to ensure procedure NEDP-5, Design Document Reviews was consistent with TVANQA- PLN89-A, Nuclear Quality Assurance Plan |
Site: | Browns Ferry ![]() |
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Report | IR 05000259/2012004 Section 4OA3 |
Date counted | Sep 30, 2012 (2012Q3) |
Type: | Finding: Green |
cornerstone | Initiating Events |
Identified by: | Self-revealing |
Inspection Procedure: | IP 71153 |
Inspectors (proximate) | C Stancil D Dumbacher E Guthrie D Jones C Kontz P Niebaum J Montgomery L Pressley T Stephen |
CCA | H.7, Documentation |
INPO aspect | WP.3 |
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Finding - Browns Ferry - IR 05000259/2012004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Browns Ferry) @ 2012Q3
Self-Identified List (Browns Ferry)
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