ML20154S164

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Special Rept 86-05:on 860310,while diesel-driven Fire Pump Out of Svc for maint,motor-driven Fire Pump Tripped on Ground Fault.Cause Undetermined.Motor Inspected & Returned to Svc
ML20154S164
Person / Time
Site: Rancho Seco
Issue date: 03/24/1986
From: Latham W
SACRAMENTO MUNICIPAL UTILITY DISTRICT
To: Martin J
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
86-05, 86-5, RJR-86-119, NUDOCS 8603310381
Download: ML20154S164 (2)


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esuun SACRAMENTO MUNICPAL UTIUTY DISTHICT i 6201 S Street, P.O. Box 1583o. Sacramento CA 95852 1830.1916)452-3211 AN ELECTRIC SYSTEM SERVING THE HEART OF CAllFORNIA RJR 86-119 March 24,1986 J B MARTIN REGIONAL ADMINISTRATOR REGION V 0FFICE OF INSPECTION AND ENFORCEMENT ATTENTION DOCUMENT CONTROL DESK U S NUCLEAR REGULATORY COMMISSION WASHINGTON DC 20555 GCCKET N0. 50-312 LICENSE NO. DPR-54 SPECIAL REPORT N0. 86-05, LOSS OF FIRE PUMPS The Sacramento Municipal Utility District hereby submits Special Report 86-05 in accordance with Rancho Seco Nuclear Generating Station Technical Specifications, Sections 3.14.2.3 and 6.9.5.E.

During cold shutdown conditions, while attempting to start the motor driven fire pump (P-440), on March 10, 1986, a trouble alarm was received in the control room for the 3E Bus. An operator was sent to investigate and it was determined that the motor driven fire pump tripped on a ground fault.

Coincident with the trip of the motor driven fire pump, the diesel driven fire pump was out-of-service for major maintenance.

Corrective action was taken immediately to have the motor inspected prior to reenergizing the breaker. The motor was determined to be operable and the breaker was reenergized.

The motor driven pump was then returned to service and operated properly. The motor driven fire pump was out-of-service for approximately 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />, which is less than the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> specified in Technical Specification 3.14.2.3.a.

In addition, the breaker was inspected and no apparent cause of the ground fault trip was identified.

There was, however, a thundershower passing over the site _at the time of the trip.

The NRC was notified pursuant to Technical Specification 3.14.2.3.b.(1).

No fires were experienced during the period that the motor driven pump was out-of-service.

The reasons for the diesel driven fire pump being out-of-service will be provided as a separate special report, scheduled for submittal to the NRC by April 2, 1986.

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PDR fp RANCHO SECO NUCt. EAR GENERATING STATION O 1444o Twin Cities Road, Herald, CA 95638-9799;(209) 333-2935 L

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J B MARTIN March 24, 1986 If you have any questions concerning this report, please contact Mr. Ron Colombo at the Rancho Seco Nuclear Generating Station Unit No' 1,

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W. K. LATHAM ACTING GENERAL MANAGER