05000368/FIN-2014002-03
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Finding | |
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| Title | Failure to Land Signal Wire From Differential Relay Output to Generator Lockout Relay |
| Description | Inspectors documented a self-revealing finding for the licensees failure to correctly land the signal wire from the Unit 2 auxiliary transformer differential relay output contacts to the main generator lockout relay, which contributed to the explosion of the Unit 2 auxiliar
transformer. The licensee documented the issue in Condition Report CR-ANO-2-2013-02242. The licensee correctly landed the wire and aligned startup transformer 3 (preferred offsite power source) to carry the plant loads during normal power operations and restarted the plant on January 10, 2014. Inspectors concluded that the licensees failure to correctly land the wire, in accordance with the drawing, in the common circuit for the differential current relays was a performance deficiency. The performance deficiency was more than minor because it was associated with the human performance attribute of the initiating events cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, the non-landed wire resulted in catastrophic failure of the Unit 2 auxiliary transformer after a fault occurred. Using Inspection Manual Chapter 0609, Attachment 4, Initial Characterization of Findings, and Appendix A, The Significance Determination Process (SDP) for Findings At-Power, Exhibit 1, Initiating Events Screening Questions, the inspectors determined that the finding was of very low safety significance (Green) because the finding did not result in a reactor trip and the loss of mitigation equipment relied upon to transition the plant from the onset of a trip to a stable shutdown condition. This finding did not have a cross-cutting aspect associated with it because the most significant contributor was not indicative of present performance. Specifically, the last time the wire could have been removed was 1995 (Section 4OA3). |
| Site: | Arkansas Nuclear  |
|---|---|
| Report | IR 05000368/2014002 Section 4OA3 |
| Date counted | Mar 31, 2014 (2014Q1) |
| Type: | Finding: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | A Fairbanks B Tindell C Alldredge G Werner J Melfi L Carson M Young |
| INPO aspect | |
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Finding - Arkansas Nuclear - IR 05000368/2014002 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Arkansas Nuclear) @ 2014Q1
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