05000325/FIN-2013005-01
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Finding | |
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Title | Failure of Transformer Common C and Loss of Emergency Core Cooling System Keepfill |
Description | The inspectors opened an unresolved item (URI) to determine if a performance deficiency exists with the loss of Transformer Common C and the emergency core cooling system (ECCS) keepfill system. On February 22, 2012, the Common C 4160/480V transformer failed. This resulted in a loss of power to the circulating water intake pump (CWIP) traveling screen motors, which lead to high delta-pressure across the traveling screens. The CWIP 1B tripped due to high delta-pressure across its associated traveling screen. In anticipation of a loss of condenser vacuum, the licensee inserted a manual reactor SCRAM on Unit 1. As a result of the SCRAM, reactor water level reached the Reactor Water Level - Low Level 1 actuation set point and the Primary Containment Isolation System (PCIS) Groups 2 and 6 isolations occurred. Additionally, the Main Steam Isolation Valves (MSIVs) (PCIS Group 1) were manually closed prior to reaching the Condenser Vacuum Low actuation set point. Also, a loss of the Common C Transformer resulted in the loss of the demineralized water transfer pumps, which is the source of keepfill for the ECCS piping. With the loss of keepfill, ECCS systems started to depressurize, with Unit 1 ECCS depressurizing in 17 minutes and Unit 2 ECCS depressurizing in 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 29 minutes. With depressurized ECCS, both units entered TS 3.0.3. The licensee provided temporary power to a single demineralized water pump and successfully filled and vented the ECCS within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and 16 minutes of the event. The inspectors opened an URI to determine if a performance deficiency exists with the loss of Transformer Common C and the ECCS keepfill. The licensee entered this issue in the CAP as NCR 519193. This issue is being tracked as URI 05000325/2013005-01, Failure of Transformer Common C and Loss of Emergency Core Cooling System Keepfill. |
Site: | Brunswick |
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Report | IR 05000325/2013005 Section 1R12 |
Date counted | Dec 31, 2013 (2013Q4) |
Type: | URI: Green |
cornerstone | Mitigating Systems |
Identified by: | NRC identified |
Inspection Procedure: | IP 71111.12 |
Inspectors (proximate) | A Nielsen A Vargas D Bacon G Hopper M Catts M Meeks M Schwiegj Laughlinm Bates M Catts M Schwieg P Lessard D Jackson G Hopper J Austin J Dodson |
INPO aspect | |
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Finding - Brunswick - IR 05000325/2013005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Brunswick) @ 2013Q4
Self-Identified List (Brunswick)
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