05000361/LER-2007-005, For San Onofre, Unit 2 Regarding Loose Electrical Connection Results in Inoperable Pump Room Cooler
| ML082910134 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 10/16/2008 |
| From: | Hochevar A Southern California Edison Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 07-005-00 | |
| Download: ML082910134 (2) | |
| Event date: | |
|---|---|
| Report date: | |
| 3612007005R00 - NRC Website | |
text
SOUTHERN CALIFORNIA An EDISON INTERNATIONAL@ Company October 16, 2008 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555-0001
Subject:
Docket No. 50-361 Licensee Event Report No. 2007-005 San Onofre Nuclear Generating Station, Unit 2
Dear Sir or Madam:
This submittal provides a voluntary Licensee Event Report (LER) 2007-005 to report the inoperability of a pump room cooler due to a loose electrical connection. Neither the health nor the safety of plant personnel or the public was affected by this occurrence.
If you require any additional information, please contact me.
Sincerely, Albert R. Hochevar Station Manager Unit 2 LER No. 2007-005 cc:
E. E. Collins, NRC Regional Administrator, Region IV G. G. Warnick, NRC Senior Resident Inspector, San Onofre Units 2 & 3 P.O. Box 128 San Clemente, CA 92674-0128
Abstract
On 3/1/07 with Unit 2 at about 99 percent power, the Spent Fuel Pool (SFP) Pump [DA] Room Emergency Air Conditioning Fan was started for air flow measurement and tripped on thermal overload. SCE found the phase A connection loose with evidence of arcing. SCE concluded this caused high current in the other 2 phases and the trip. SCE subsequently determined the loose connection likely resulted from incomplete maintenance on 10/27/06 when the thermal overloads were replaced. SCE considers the fan was inoperable from 10/27/06 to 3/1/07.
The Bases for Technical Specification 3.7.10, Emergency Chilled Water [KM], requires SCE to enter the applicable Action for supported equipment if an inoperable room cooler is not restored within 14 days. This Action was Licensee Controlled Specification 3.7.106.A. The inoperability was not recognized and the Action was not entered. Failure to enter this Action does not violate TS, but it does not meet its expectations.
SCE verified that there was no increase in decay heat load in the SFP from 10/27/06 to 3/1/07. Therefore, there was little safety significance to the event.
SCE identified this event in an 8/18/08 audit of previous occurrences of loose electrical connections. The audit and assessment for reportability is part of corrective actions resulting from previous events (LER 2-2008-006, submitted 9/17/08 and LER 3-2005-01, submitted 8/23/05).