Etats-Unis : Brunswick : Local control capability of emergency diesel generator 2 not available under certain conditions

29 août 2012

Le groupe électrogène fournissant l’électricité de secours de la centrale est indisponible dans certaines configurations.

Available in english only.

Facility : BRUNSWICK - Region : 2 State : NC - Unit : [1] [2] Event Date : 08/29/2012 - Event Time : 21:34 - Emergency Class : NON EMERGENCY

Event Text

"On August 28, 2012, during planned maintenance on Emergency Diesel Generator No.2, a post-maintenance continuity testing associated with the Alternate Safety Shutdown (ASSD) switch on Emergency Diesel Generator No.2 (EDG 2) revealed unexpected results when the switch was taken to the LOCAL position. Troubleshooting activities determined the switch to be operating properly, meaning the contacts are actually open. However, a current path preventing isolation of the control room circuit remained. It was determined that a wire, not identified in EDG wiring diagrams, created a short between two ASSD switch contacts.

"At 2134 hours Eastern Daylight Time (EDT) on August 29, 2012, it was concluded that the condition may impact the ability of EDG 2 to perform its intended ASSD function. In the event of a fire, an induced fault could potentially affect the ability to locally control EDG 2. Local control of EDG 2 is credited in the safe shutdown analysis. Therefore, this condition is being reported in accordance with 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition.

"This condition did not result in any adverse impact to the health and safety of the public. This condition has no affect on the Technical Specification operability of EDG 2 and it was fully capable of performing its intended design basis accident response functions given the as-found condition of the circuitry.

"The initial safety significance of this condition is minimal. This condition has no affect on the Technical Specification operability of EDG 2 and it was fully capable of performing its intended design basis accident response functions given the as-found condition of the circuitry.

"Repairs to the ASSD switch wiring have been completed. Post maintenance testing is occurring at this time. Planning is in progress to inspect the remaining Emergency Diesel Generators for similar conditions."

The licensee has notified the NRC Resident Inspector.

https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2012/20120831en.html

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