ML20148B142

RO-18-16:on 781024,while Generator B Out of Svc for Maint, Voltage Regulator for Generator Malfunctioned & Generator a Shutdown.Cold Shutdown of Reactor Commenced.Generator a Returned to Svc.Full Rept to Follow

ML20148B142
Person / Time
Site:	Rancho Seco
Issue date:	10/25/1978
From:	Oubre R SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
References
RJR-78-476, NUDOCS 7810310087
Download: ML20148B142 (1)

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1SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT C 1708 59th Street, Box 15830, Sacramento, Califorrua 95813;(916)452 3211 RJR 78-476 October 25, 1978 U. S. Nuclear Regulatory Commission ATTN: Mr. R. H. Engelken, Director NRC Operations Of fice, Region V 1990 North Cali fornia Boulevard Walnut Creek Plaza, Suite 202 Walnut C reek, Cali fornia 94596 4

Re: Operating License DPR-54 Docket No. 50-312 Reportable Occurrence 78-16

Dear Mr. Engelken:

The Sacramento Municipal Utility District informed Mr. A. Johnson of NRC this date of Reportable Occurrence 78-16 as defined by Regulatory Guide 1.16, Section C.2.a(2).

On October 24, 1978, at 11: 50 a.m., the "A" diesel generator was paralleled to the "A" Nuclear Service Bus running at partial load, while the "B" diesel generator was out of service due to maintenance work associated with fire protection modifications. At 11:50 a.m. the voltage regulator circuit for the "A" diesel generator malfunctioned, resulting in shutting down of the "A" diesel gene ra tor. This constituted a loss of both diesel generators and, in accordance wi th Technical Specifications Paragraph 3 7.3, a shutdown was commenced with the plan of putting the reactor in a cold shutdown condition.

At 7: 05 p.m. on October 24, 1978, the "A" diesel generator was returned to service and paralleled at partial load. The reactor shutdown was terminated.

A detailed report will follow within fourteen (14) days.

Respectfully submitted, i >

J

\ /

R. P. Oubre' Acting Manager, Nuclear Operations RP0:HH: sal .

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