05000277/FIN-2007002-04
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Finding | |
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Title | Incorrect size breaker resulted in a fire in the 4T4 480 volt load center |
Description | At approximately 9:16 a.m. on February 27, 2007, a fire was suspected to have started based on the receipt of numerous secondary plant alarms in the main control room (MCR) and the report of smoke near the 4T4\' 480 Volt load center. The inspectors responded to the MCR following a site announcement for the fire brigade to respond to a suspected fire in the Unit 3 turbine building. The inspectors monitored the operators response to the event and the status of plant equipment. The observations were primarily focused on the nuclear safety aspects of the plants and operators responses. The inspectors also monitored the response of PBAPSs emergency response organization to the declaration of an UE. Subsequent to the fire, the inspectors discussed the fire with operations, engineering and PBAPS management personnel to gain an understanding of the event and to assess their followup actions. The inspectors reviewed operator logs and operators actions taken in accordance with licensee procedures. Based on the operators narrative logs, the fire brigade was dispatched to the Unit 3 turbine building at approximately 9:20 a.m. Fire personnel investigated and notified the MCR that an actual fire existed at 9:38 a.m. An Unusual Event for a fire not extinguished within 15 minutes (emergency action level (EAL) HU6) was declared at 9:41 a.m. All state and local government notifications were completed by 9:59 a.m. and the NRC Headquarters Operations Officer was notified of the event at 10:36 a.m. The fire was considered to be extinguished at approximately 10:32 a.m. At 11:37 a.m., the Unusual Event was terminated. Prior to the report of the potential fire, Unit 3 was operating at full power. As a result of fire and the associated response actions, numerous non-safety-related loads powered by the 4T4\' 480 Volt load center were de-energized. Equipment that was de-energized included: the B isophase bus cooler fan, the B drywell chiller, the B recirculation pump speed controller, the leading edge flow meters and the B reactor feed pump. Plant operators took the required TS actions and responded to the equipment losses by performing controlled reactor power reductions and stabilized the plant at approximately 50 percent of rated power. The inspectors verified that the required reports were made during the event and that no further reports are planned. The inspectors also verified that this issue (IR 569889) was placed into the CAP. Preliminarily, PBAPS has determined that the fire resulted from an apparent mismatch between the ratings of one breaker and its cubicle in the 4T4\' 480 volt load center. A root cause investigation was ongoing at the end of the inspection period and will be reviewed by the inspectors during a future inspection period. At the close of this inspection period, the inspectors were reviewing the event and awaiting the results of the root cause evaluation to understand the potential performance deficiencies. This issue is unresolved pending review of PBAPSs causal evaluation and corrective actions by the inspectors to characterize the issue. URI 05000277/2007002-04, Incorrect Size Breaker Resulted in a Fire in the 4T4\' 480 Volt Load Center. |
Site: | Peach Bottom |
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Report | IR 05000277/2007002 Section 4OA3 |
Date counted | Mar 31, 2007 (2007Q1) |
Type: | URI: |
cornerstone | Mitigating Systems |
Identified by: | NRC identified |
Inspection Procedure: | IP 71153 |
Inspectors (proximate) | M Brown L Cheung J Caruso J D'Antonio K Mangan D Tifft J Krafty R Nimitz F Bowerm Brownr Fuhrmeister R Nimitz R Cureton F Bower N Perry |
INPO aspect | |
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Finding - Peach Bottom - IR 05000277/2007002 | |||||||||||||
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Finding List (Peach Bottom) @ 2007Q1
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