05000361/LER-1982-016, Forwards LER 82-016/01L-0.Detailed Event Analysis Submitted

Forwards LER 82-016/01L-0.Detailed Event Analysis Submitted

ML20053E572
Person / Time
Site:	San Onofre
Issue date:	06/01/1982
From:	Ray H SOUTHERN CALIFORNIA EDISON CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20053E573	List: 05000361/LER-1982-016, Forwards LER 82-016/01L-0.Detailed Event Analysis Submitted 05000361/LER-1982-016-01, /01L-0:on 820516,during Mode 4 Operation,Two Inverters to Vital Buses de-energized Simultaneously. Followup Rept Will Be Provided by 820615
References
NUDOCS 8206090030
Download: ML20053E572 (2)

LER-1982-016, Forwards LER 82-016/01L-0.Detailed Event Analysis Submitted

Event date:
Report date:
3611982016R00 - NRC Website

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h C; en S A N ONOF RE f,UC LE A R GE NER A TING S T A T TON P.O. B O X 128 a-S A N C L EME N T E. C A LIF ORNI A 92672

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p H. B. R A Y TELEPHONE SF A F TON M AN AGE R q r14 g 4,2 y 700 June 1,1982 U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region V 1450 Maria Lane, Suite 210 Walnut Creet, California 94596-5396 Attention: Mr. R. H. Engelken, Regional Administrator Oear Sir:

Subject:

Docket No. 50-361 Licensee Event Report No.82-016 San Onofre Nuclear Generating Station, Unit 2

Reference:

(a)

Facsimile Transmission, SCE letter H.B. Ray (SCE) to R.H. Engelken (NRC) dated May 17, 1982 l

This letter provides an interim report to the prompt notification of reference (a) pursuant to Technical Specification Section 6.9.1.12.b, of an event involving Limiting Condition for Operation 3.8.3.1 and its associated Action statements. The follow-up report normally provided in 14 days and a completed Licensee Event Report will be provided by June 15, 1982.

On May 16,1982 an investigation into the source of radio frequency interference on reactor protection system channel "D" log power indication was in progress. Trouble shooting had indicated that the prime suspects were the voltage inverters supplying the 120 VAC Vital Busses 2Y03 and 2YO4.

While in mode 4, limiting Condition for Operation (LCO) 3.8.3.1 requires that each of the 4 Vital Busses be energized from it's e ociated inverter connected to separate D.C. busses. Action statement (b), associated with this L.C.0,, permits one AC Vital Bus to be energized from its alternate source for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> before cooldown would be required.

Contrary to the provisions of Action Statement (b), two AC Vital Busses were energized from alternate sources for a period of 10 minutes, p

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R.H. Engelken June 1,1982 Our review of this matter has included an independent review and evaluation intended to identify corrective actions warranted by this particular occurence as well as any need for more generic corrective action in procedures and training.

The follow-up report and Licensee Event Report to be provided by June 15, 1982 will address the conclusions of this independent review.

If there are any questions regarding the above, please contact me.

M9 lnur

Enclosure:

LER 82-016 i

U.S. Nuclear Regulatory Commission cc:

Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Office of Management Information and Program Control Institute of Nuclear Power Operations (INP0)

A.E. Chaffee (USNRC Resident Inspector Unit 2) i