ML20083H713

Interim Deficiency Rept Re Mechanical Snubbers Supplied by Pacific Scientific Co.Initially Reported on 831117.Seven Snubbers Tested Revealed Broken Capstan Spring Tang. Investigation Ongoing.Final Rept by 840616

ML20083H713
Person / Time
Site:	Nine Mile Point
Issue date:	12/16/1983
From:	Mangan C NIAGARA MOHAWK POWER CORP.
To:	Starostecki NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
(7822), NUDOCS 8401130321
Download: ML20083H713 (2)

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. NIAGARA MOHAWK POWER CORPORATION /300 ERIE BOULEVARD WEST. SYRACUSE, N.Y.13202/ TELEPHONE (315) 4741511 December 16, 1983 (7822) l Mr. R. W. Starostecki, Director U.S. Nuclear Regulatory Commission Region I Division of Project and Resident Programs 631' Park Avenue King of Prussia, PA 19406 Re: Nine Mile Point Unit 2 Docket No.-50-410-

Dear Mr. Starostecki:

- Enclosed is an interim report for the problem concerning mechanical snubbers supplied by Pacific Scientific Company. This problem was reported via telecon to R. Gallo of your staff on November 17, 1983.

Very truly yours, CA.G W g C. V. Mangag Vice President Nuclear Engineering & Licensing CVM/TL:ja Enclosure xc: Director of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 Mr. R. Gramm, P,esident Inspector l

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NIAGARA M0 HAWK POWER CORPORATION NINE MILE POINT UNIT 2 DOCKET N0. 50-410 LInterim Report for a Problem Concerning Mechanical Snubbers Description-of -the-Problem The problem concerns the mechanical snubbers supplied by Pacific Scientific Company. The vendor has informed Stone & Webster Engineering Corporation thet during testing of mechanical snubber Model PSA-1, at another plant, four of

- the seven snubbers tested revealed a broken capstan spring tang. Pacific Scientific indicated that the broken springs were sent for an independent metallurgical examination, and the metallurgical report indicates spring cracking occurred because of stresses induced-during spring forming, which

. caused hydrogen cracking during subsequent silver plating. The capstan springs are manufactured for Pacific Scientific Company by a spring manufacturer. Pacific Scientific has also indicated that the problem pertains to only nechanical snubber Models PSA-1 and PSA-3 with certain serial numbers.

The matter.is still under investigation, and a final report will be submitted

-by June 16, 1984.