05000259/FIN-2012004-03
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Finding | |
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Title | Automatic Reactor Scram Due to Inadequate Testing of Current Transformer |
Description | A self-revealing finding (FIN) was identified for the licensees failure to adequately test a Unit 3 main turbine generator current transformer (CT) as required by TVA-NQA-PLN89-A, Nuclear Quality Assurance Plan which resulted in the improper wiring of the CT. The licensee switched the CT leads to correct the input to the main transformer relay, adequately tested all other new Unit 3 relays, implemented a transition plan to incorporate the protective relay group into the nuclear organization, and planned post startup monitoring for the Unit 1 and 2 digital differential protective relays. The licensee entered this issue into their corrective action program as PER 558183. 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 adequately test a Unit 3 main turbine generator CT 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 was determined to be of very low safety significance (Green) because it did not contribute to both a reactor trip and the loss of mitigation equipment relied upon to transition the plant from the onset of the trip to a stable shutdown condition. The cause of this finding was directly related to the cross-cutting aspect of Supervisory and Management Oversight in the Work Practices component of the Human Performance area, because the supervisors failed to ensure proper procedure quality, procedure usage, worker qualification, and proper work preparation associated with the protective relay groups work activities such that nuclear safety was supported. |
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.2, Field Presence |
INPO aspect | LA.2 |
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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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