ML20132F352

Preliminary Part 21 Rept Re 3.5-inch Crack on Snubber Ball Bearing.Vendor Attempting to Have Bearing Returned for Exam & Evaluation by Skf Industries.Next Rept Will Be Submitted When Significant Info Available

ML20132F352
Person / Time
Site:	Prairie Island
Issue date:	09/26/1985
From:	Laurenson A GRINNELL CORP. (FORMERLY ITT GRINNELL CORP.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
References
REF-PT21-85-432-000 PT21-85-432, PT21-85-432-000, NUDOCS 8510010306
Download: ML20132F352 (2)

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"T 1T 1 ITTGrinnellCorporation Executive Offices i 260 WestExchangeStreet Providence, RhodeIsland02901  !

CIRTIFIED MAIL - RE'IERN RECEIPT ggg September 26, 1985 Director, Office of Inspection andTnforcement U. S. Nuclear Regulatory Comission Washington, DC 20555

Dear Sir:

This letter provides a Part 21 report of a potential safety concern ITT Grinnell has under consideration. This report is preliminary because we do not have at this time enmgh information to know whether ITT Grinnell is required to file this report.

ITT Grinnell furnished to Northern ' tates S Power (NSP) four snubbers to replace 'four non-ITT Grinnell snubbers. The hydraulic cylinders for the ITT Grinnell snubbers, including the bearings, were furnished by Chicago Fluid Power, Roto Thrust Division.

The concern is that me bearing for use m one of the replacement snubbers has been reported to cmtain a hairline crack approximately 31/2 inches long m the ball.

The snubber is designed for use m NSP's Prairie Island Plant as replacement for the installed snubbers. A total of only fcur such replacement snubbers have been provided by ITT Grinnell. Each of the four snubbers utilize two bearings #SKF GEZ-312-ESB for a total of 8 bearings. These bearings were manufactured in Germany by SKF Industries, Inc. which has an office at 9800 McKnight Road, Pittsburgh, Pennsylvania 15237. The bearings are load rated at 1102.5 ' kips. The rated load of the snubbers is 900 kips, fDR DOC DR S I 1 0

'ID: Nuclear Regulatory Commission PAGE2 The four snubbers were each designed for 1000 kips load. Each snubber was successfully tested by ITT Grinnell at 1000 kips. No crack was observed by ITT Grinnell after these tests and before delivery, and we have no basis for believing that the crack existed before delivery.

The above numbered bearing has not been utilized in any other snubber furnished by ITT Grinnell to EP or to any other. customer.

After delivery and prior to completion of installation of this snubber by EP this bearing was visually examined by EP personnel.who observed. the hairline crack and reported it to ITT Grinnell by telephone. An ITT Grinnell employee was imediately sent to the EP site to visually verify the existence of .the crack. NSP personnel reported to ITT Grinnell that they visually examined the other seven bearings in the four snubbers and saw no other cracks.

Chicago Fluid Power has been kept abreast of the situation. SKF Industries has also been informed by. telephone of this crack. SKF Industries indicated during that telephone conversation that this crack is unique.

ITT Grinnell is attempting to have the . bearing returned to it so that the bearing may be returned to SKF Industries for examination and evaluation.

ITT Grinnell will provide the EC with a further report on this matter as soon as significant new information becomes available.

-If you have any questions, please contact Mr. E. Beffa or myself at the above nunber.

Very truly yours, ITT p NNE N Ar ur La renson Corporate Quality Assurance Manager AL: tar CC: Gerald Gore, EP ~

D. L. IIenry SKF Industries R. Mills, Cilicago Fluid Power 7864L-