05000361/LER-1982-080, Forwards LER 82-080/03L-0.Detailed Event Analysis Submitted

Forwards LER 82-080/03L-0.Detailed Event Analysis Submitted

ML20065H502
Person / Time
Site:	San Onofre
Issue date:	09/22/1982
From:	Ray H SOUTHERN CALIFORNIA EDISON CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20065H505	List: 05000361/LER-1982-080, Forwards LER 82-080/03L-0.Detailed Event Analysis Submitted 05000361/LER-1982-080-03, /03L-0:on 820823,during Mode 4 Feeder Breaker Testing After Returning Breaker 2A0101 to Svc,Feeder Breaker 2A0104 Failed to Open.Cause Unidentified.Event Considered Isolated.No Further Action Deemed Necessary
References
NUDOCS 8210050151
Download: ML20065H502 (2)

LER-1982-080, Forwards LER 82-080/03L-0.Detailed Event Analysis Submitted

Event date:
Report date:
3611982080R00 - NRC Website

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<~s S AN ONOFRE NUCLE AR GENER ATING S T A TION P.O. B' O 1 12 9 S AN C LEME NT E. C A LIF ORNI A 92672

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September 22, 1982 cT T ON o.N.Ga.

U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region V 1450 Maria Lane, Suite 210 Walnut Creek, California 94596-5368 Attention:

Mr. R. H. Engelken, Regional Administrator

Dear Sir:

Subject: Docket No. 50-361 30-Day Report Licensee Event Report No.82-080 San Onofre Nuclear Generating station, Unit 2 l

This submittal is in accordance with the reporting requirements of Section 6.9.1.13b of Appendix A to Facility Operating License NPF-10. It describes a reportable condition involving Limiting Condition for Operation (LCO) 3.8.1.1 associated with A.C. electrical power sources. A completed copy of LER 82-080 is' enclosed.

On August 23,1982 at 1401, while in kbde 4 and returning feeder breaker 2A0101 to service after repair, feeder breaker 2A0104 failed 10 open during testing for proper breaker operation. Reactor Coolant Pump (RCP)-004, the only load on bus 2A01, was then secured. At the time, and in accordance with Technical Specification 3.8.1.la, the two offsite transmission networks were feeding the reserve auxiliary transformer 2XR3 and main transformer 2XM/ unit auxillary transformer 2XU1. To manually open feeder breaker 2A0104 for trouble shooting, main transformer 2XM was de-energized and the associated Action Statement entered.

As required by this Action Statement, feeder breaker 2A0104 was racked out and power was restored to 2XM at 1410 on August 23, 1982.

On August 24, 1982, the breaker was placed in a breaker test stand and after repeated testing, proved to be working satisfactorily. The breaker was then racked into its cubicle and tested satisfactorily. This event is believed to be an isolated occurrence and no further corrective action is planned.

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1 L R.I' H. Engel k:n September 22, 1982

.Since the redundant offsite transmission network remained operable as

- well as the two standby diesel generators, both of which are capable of supplying electrical power to all necessary engineered safety feature systems, there was no impact on health and safety of plant personnel or the public, if there are any questions regarding the above, please contact me.

Sincerely, Heby Ir>6 Enclosure: LER 82-080 cc:

A. E. Chaf fee (USNRC Resident inspector, San Onof re Unit 2)

U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Of fice of Management Infonnation and Program Cc,r. trol Institute of_ Nuclear Power Operations