05000368/FIN-2014002-02
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Finding | |
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Title | Failure to Correctly Install Flexible Link Bolted Connection on Phase C of 6.9 kV Bus |
Description | Inspectors documented a self-revealing finding for the licensees failure to correctly install the flexible link bolted connection on phase C of the 6.9 kV non-segregated bus of the Unit 2 auxiliary transformer, which contributed to the explosion of the Unit 2 auxiliary transformer. The licensee documented the issue in Condition Report CR-ANO-2-2013-02242. The licensee 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. The transformer is scheduled to be replaced during the upcoming refueling outage starting in May. Inspectors concluded that the licensees failure to correctly install the flexible link bolted connection on phase C of the Unit 2 auxiliary transformer 6.9 kV bus 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 incorrectly installed flexible link bolted connection resulted in a reactor trip. 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 mos significant contributor was not indicative of present performance. Specifically, the flexibl links and insulation had been installed in this configuration since at least 197 (Section 4OA3). |
Site: | Arkansas Nuclear |
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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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