ENS 44425
ENS Event | |
---|---|
15:10 Aug 19, 2008 | |
Title | Alternate Safe Shutdown Local Start Capability of All Four Emergency Diesel Generators May Not Be Available Under Certain Conditions |
Event Description | On August 18, 2008, during biennial (i.e., every two years) non-Technical Specification related testing, Emergency Diesel Generator (EDG) No. 4 failed to start from the EDG local control panel. This occurred with the EDG aligned for Alternate Safe Shutdown (ASSD) response versus its normal alignment. The purpose of the testing is to confirm that the EDG control logic is isolated from the control room and only operable via local controls. Based on troubleshooting activities, it was discovered that this failure to start was due to improper wiring in the circuitry associated with the EDG lockout relay. The improper wiring was introduced by a modification performed on all four EDGs in 2007.
At 1110 hours0.0128 days <br />0.308 hours <br />0.00184 weeks <br />4.22355e-4 months <br /> Eastern Daylight Time (EDT) on August 19, 2008, it was concluded that this condition impacted the ability of EDG Nos. 2, 3, and 4 to perform their intended ASSD function. The 2007, modification affected the termination point for the power to the EDG lockout relay reset coil. Per the modification, this termination point was incorrectly connected to the downstream side of the alternate shutdown isolation switch which results in a loss of power to the lockout reset when the switch is placed in local control. Therefore, in the unlikely event of a fire, an induced failure could potentially initiate a lockout signal which could not be reset from the EDG local control panel. Although the modification was installed on all four EDGs, only the local control of EDGs 2, 3, and 4 is credited in the safe shutdown analysis. This condition does not affect the Technical Specification operability of the EDGs and they remain fully capable of performing their intended design basis accident response functions. The NRC Resident Inspector has been notified. Compensatory fire watches have been established and an engineering change package to correct the condition is being developed. |
Where | |
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Brunswick ![]() North Carolina (NRC Region 2) | |
Reporting | |
10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
LER: | 05000325/LER-2008-006 |
Time - Person (Reporting Time:+2.28 h0.095 days <br />0.0136 weeks <br />0.00312 months <br />) | |
Opened: | Curtis Dunsmore 17:27 Aug 19, 2008 |
NRC Officer: | Bill Huffman |
Last Updated: | Aug 19, 2008 |
44425 - NRC Website
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Unit 1 | |
---|---|
Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (100 %) |
Unit 2 | |
---|---|
Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (100 %) |
WEEKMONTHYEARENS 499352014-03-20T13:11:00020 March 2014 13:11:00
[Table view]10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Fire-Related Unanalyzed Condition That Could Impact Credited Safe Shutdown Analysis ENS 492222013-07-29T14:42:00029 July 2013 14:42:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Fire Related Unanalyzed Condition That Could Impact Credited Safe Shutdown Analysis ENS 482532012-08-30T01:34:00030 August 2012 01:34:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Local Control Capability of Emergency Diesel Generator #2 Not Available Under Certain Conditions ENS 474522011-11-17T18:45:00017 November 2011 18:45:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition on Startup Following Maintenance Outage ENS 473412011-10-13T14:00:00013 October 2011 14:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Fire Related Unanalyzed Condition That Could Impact Equipment Credited in Safe Shutdown Analysis ENS 444252008-08-19T15:10:00019 August 2008 15:10:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Alternate Safe Shutdown Local Start Capability of All Four Emergency Diesel Generators May Not Be Available Under Certain Conditions ENS 411602004-10-29T20:00:00029 October 2004 20:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Discovered in 480 Volt Switchgear Room 2014-03-20T13:11:00 | |