05000312/LER-1982-005, Forwards LER 82-005/03L-0.Detailed Event Analysis Submitted

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Forwards LER 82-005/03L-0.Detailed Event Analysis Submitted
ML20042A917
Person / Time
Site: Rancho Seco
Issue date: 03/12/1982
From: Mattimoe J
SACRAMENTO MUNICIPAL UTILITY DISTRICT
To: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20042A918 List:
References
NUDOCS 8203240272
Download: ML20042A917 (2)
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LER-1982-005, Forwards LER 82-005/03L-0.Detailed Event Analysis Submitted
Event date:
Report date:
3121982005R00 - NRC Website
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SACRAMENTO MUNICIPAL UTILITY DISTRICT O 6201 S Street, Box 15830, Sacramento, California 95813: (916) 452-3211 E8? MA3 I 7 A? ll: 03 March 12, 1982 EEC' f V !.

R H ENGELKEN, REGIONAL ADMINISTRATOR REGION V 0FFICE OF INSPECTION AND ENFORCEMENT X

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In accordance with Rancho Seco Nuclear Generating Station Technical Specifications Sections 3.7.2 and 6.9.4.2.b and Regulatory Guide 1.16 Section C.2.b(2), the Sacramento Municipal Utility District hereby submits the following 30-day report of Licensee Event Report 82-05.

On February 10, 1982, the "B" Emergency Diesel Generator monthly surveillance was performed. When the diesel was secured, a "B" Diesel Trouble alarm was received in the control room. This alarm was immediately investigated and a high fuel filter differential pressure alarm was observed on the Engine Control Panel in the "B" Diesel Generator Room.

It was assumed that this was the function that had initiated the trouble alarm in the control room (this condition will, in fact, cause that control room alarm to annunciate).

Since a high fuel filter differential pressure will not prevent the diesel from operating, a work recuest was initiated to repair / replace the fuel filter.

On February 11, 1982 the fuel filters were replaced.

The "B" Diesel Trouble alana did not clear, so the Shift Supervisor requested that the Electrical Maintenance group investigate a possible annunciator problem.

Electrical Maintenance personnel found the fault flag dropped on the "B" diesel generator output breaker, 52-4B11. This had appar-ently been caused when the diesel generator had been unloaded and secured during the surveillance test on February 10. The likely cause would be a reverse power trip energizing the relay, which could have been the result of improperly unloading the diesel at the end of the surveillance.

This relay would have in turn energized the 486 relay, Mg 5

preventing the closure of the "B" diesel generator output breaker.

Thus, the "B" diesel generator had actually been inoperable since j (

approximately 0904 on February 10. The "B" diesel was declared inoper-able at 1330 on February 11; was subsequently started; and the monthly surveillance was again performed to verify operability at 1340.

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R. H. Engelken March 12,1982 It should be noted that the operator had the capability to close the breaker from the control room. This was, in fact, the way the alam was finally cleared to allow the surveillance test to be performed.

This was done by pushing the " trip"~ button on panel H2ES which resets the lockout relay.

Also, the reverse power trip annunicates on the Diesel Trouble alarm but does not alarm on the Engine Control panel or the Generator panel. All other alanns that input to the Diesel Trouble alarm do have alarm lights on these panels.

Although Operations personnel checked the 4B switchgear each shift while the dropped flag condition existed, it was not observed. This is, therefore, a similar event to Licensee Event Report 81-33 which had discussed corrective actions such as providing a means to better mark the relays so that target flags would be easier to identify. A method had been developed but was not yet in place at the time of this occurrence. That method is a white frame or outline placed on the relay glass cover to define where to look for targets. These outlines are now in place.

Additionally, training for Operations personnel was conducted to ensure that the location and meaning of target flags was understood.

As a final corrective action, this relay alarm will be moved to a different annunicator, Diesel Not Ready for Autostart, which is con-sidered to be a better location for indications of any condition that would render the diesel generator inoperable.

The NRC Resident Inspector was informed of this event on February 11, 1982.

Since the "A" diesel generator was operable, there were no effects on plant.or public safety, nor were there any transients associated with this event.

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% To John J. Matt moe Assistant General Manager and C Hef Engineer cc:

I&E Washington (30 MIPC (3)

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