ML19275A242

Ro:On 790827,during Monthly Load Test,Emergency Generator Failed to Start.Cause Probably Due to Insufficient Fuel in Day Tank.Generator Inspected & Satisfactorily Retested

ML19275A242
Person / Time
Site:	University of Missouri-Columbia
Issue date:	09/27/1979
From:	Mckibben J MISSOURI, UNIV. OF, COLUMBIA, MO
To:
References
NUDOCS 7910030377
Download: ML19275A242 (2)

Text

'-

f UNIVERSITY OF MISSOURI OF Research Reactor Facility Research Pam Columbia. M,ssoun 65211 Telephone (314) 882-4211 September 27, 1979 Director of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Reference:

Docket 50-186 University of Missouri License R-103

Subject:

Failure of Emergency Electrical Generator to Start Description On August 27, 1979, while attempting to perfom a monthly load test of the emergency generator; the generator failed to start the first time it was loaded. The reactor was shutdown at the time due to the scheduled maintenance day.

The generator had been run normally on August 24, 1979 when it was started by the automatic weekly exerciser Therefore, it may be assumed that the generator was not operable during the previous three days of operation which is a deviation from Technical Specification 3.10.a.

Analysis The monthly load test of the emergency generator is performed by opening the breaker that supplies the emergency loads from offsite power, which starts the generator and then shifts the emergency loads to it. On August 27 when the breaker was opened, the generator was cranked over by the starter but did not come up te normal operating speed. After 15 seconds the operator seculad the generator and inspected it but found nothing abnormal. The load test was attemted again and the generator started and carried the emergency loads with no problem. Several cycles of stopping and starting the generator failed to reproduce the failure. Later in the day there was an unexpected loss of offsite power and the generator started and carried the emergency loads with no problem.

No definite cause was found for the failure to start but it is believed to be from not leaving sufficient scel in the day tank. Fuel is supplied from an underground tank to a small " day" tank by an electric fuel pump which is powered by the generator. When the engine starting circuit is energized a

',2 29b Q

.m@jg.

g COLUMBIA KANSAS CITY ROLLA ST. LOUIS 3q]

6 .m eam i ccxnomosmee 791oogo ,4 :

P

d ..

Directo. of Licensing September 27, 1979 Page 2 solenoid opens in the supply line between the day tank and the carburetor, allowing fuel to gravity drain into the carburetor float bowl. Puel for other purposes can be obtained by manually starting the electric fuel pump and collecting it from a manual value in the bottom of the day tank.

If this is done improperly the day tank can be left partially drained.

Corrective Action The generator was immediately inspected and retested. Additionally, the policy has been established the the emergency generator fuel system will not be used to obtain gas for other purposes. The generator has performed satisfactorily under repeated load tests.

Sincerely, k J

~*

J.C. McKibben Reactor Manager JCMK/jac cc: Dir .ctorate of Regulatory Ope rations, Region III Rec tor Advisory Committee Pes, tor Safety Subcommittee 1C,2 299