ML20215M732

Final Deficiency Rept (55(e)-86-12) Re Problem W/Air Start Valve Seat Inserts for Div I & II Emergency Diesel Generators.Initially Reported on 860619.Inserts Replaced.Air Start Distributors for Diesels Readjusted

ML20215M732
Person / Time
Site:	Nine Mile Point
Issue date:	07/03/1986
From:	Mangan C NIAGARA MOHAWK POWER CORP.
To:	Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
(55(E)-86-12), (NMP2L-0767), (NMP2L-767), NUDOCS 8611030209
Download: ML20215M732 (2)

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-< M V NIAGARA R uMOHAWK NIAGARA RIONAWK POWER CORPORAT10N/300 ERIE BOULEVARD WEST, SYRACUSE. N.Y.13202/ TELEPHONE (315) 4741511 July 3,1986 (NMP2L0767)

Mr. R. W. Starostecki, Director U.S. Nuclear Regulatory Comission Region I Division of Reactor Projects 631 Park Avenue King of Prussia, PA 19406 Re: Nine Mile Point - Unit 2 Docket No. 50-410

Dear Mr. Starostecki:

Enclosed is a final report, in accordance with 10CFR50.55(e), for the problem concerning air start valve seat inserts for Division I and II emergency diesel generators. This problem was reported via tel-con to G. Meyer of your staff on June 19, 1986.

Very truly yours, C. . g Senior Vice President CVM/GG/cla (1650H) xc: Director of Inspection and Enforcement l U.S. Nuclear Regulatory Commission Washington, DC 20555 R. A. Gram, NRC Senior Resident Inspector WP2 Project File ,

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NIAGARA M0 HAWK POWER CORPORATION NINE MILE POINT - UNIT 2 DOCKET NO. 50-410 Final Report For a Problem Concerning Air Start Valve Seat Inserts - Division I and II Emergency Diesel Generator (55(e)-86-12)

Description of the Problem During testing, Division I emergency diesel generator, 2EGS*EG1 (Cooper-Bessemer Model KSV-16T), failed to start. An investigation indicated that one air start valve seat insert had dislodged from its cylinder head, another insert was loose, and the air start distributors were out of adjustment.

It is believed that the inserts were dislodged from the cylinder heads because copper plating had been used to build up the bore hole for the insert in one cylinder and the insert used in the other head was not of the correct size.

Cooper Energy Services has determined that copper is not a suitable material for the subject application. Cooper Energy Services has also confirmed that copper has not been used for such applications in other cylinder heads of Division I and II diesels.

Analysis of Safety Implications The air starting system provides compressed air to the main engine cylinders to initiate shaft rotation prior to dieseling. The subject condition could have prevented the required amount of air from entering the engine cylinders.

As a result, the diesel may have failed to start when required. Therefore, had this condition remained uncorrected, it could have adversely affected the safety of operations of the plant.

Corrective Action The two air start valve seat inserts that were dislodged or loose from cylinder heads have been replaced. The insert counterbores were remachined and oversize inserts, with the correct interference, installed. Copper plating, used in rebuilding one cylinder bore hol e , was removed during remachining.

To ensure proper tight fit, the remaining air seat valve inserts in both Division I and II diesels were subjected to a pull test as recommended by Cooper Energy Services. The test results were found to be satisfactory.

The air start distributors for both Division I and II diesels were readjusted.