ML20080L386

Second Interim Deficiency Rept 83-07 Re Reactor Coolant Pump Bearing Failure.Initially Reported on 830505.Introduction of Foreign Matl Into Bearing Annulus Still Appears to Be Cause of Failure.Final Rept Will Be Provided by Endl of Oct

ML20080L386
Person / Time
Site:	Byron
Issue date:	09/23/1983
From:	Tramm T COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, 7327N, 83-07, 83-7, NUDOCS 8309300285
Download: ML20080L386 (1)

Text

/ N Comm:nwrith Edison

[ . ji ) cne Fi[s! Natgal_ Plaza Chicago._ libnois 1- -

} Address Reply to. Post Othee Box 767

\ s' Chicago, Ilhnois 60690 September 23, 1983 Mr. James G. Keppler, Regional Administrator

- Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137

Subject:

Byron Generating Station Units 1 and 2 Reactor Coolant Pump Bearing Failure NRC Docket Nos. 50-454 and 50-455 Reference (a): June 9, 1983, letter from E. D. Swartz to J. G. Keppler.

Dear Mr. Keppler:

This letter provides a second interim report on the f ailure of a bearing on reactor coolant pump 1A at Byron Station. This event was originally reported to the NRC pursuant to 10 CFR 50.55(e) on May 5, 1983. For NRC tracking purposes, this deficiency is numbered 83-07.

Damaged internal components from reactor coolant pump 1A have now been examined by the manufacturer, Westinghouse. They have reviewed all manufacturing records and reconstructed the history of the pump from the time of shipment from the factory to the time of the bearing failure.

Extensive metallurgical examinations have been completed. Several possible failure scenarios have been evaluated against the available information. It appears that the failure was not caused by insufficient seal injection flow, pump shaft misalignment, or deficiencies in the stellite or graphitar components. Introduction of foreign material into the bearing annulus still appears to be the cause of failure.

Westinghouse's chemical evaluations of the damaged components are not conclusive at this time. Preliminary results on some of the pieces indicate that the silicon content is higher than that which one would expect from the graphitar, stellite, and stainless steel constitu-ents. The results of further analyses should he available in October.

It is expected that a final report on this deficiency will be provided by the end of October.

Please address further questions regarding this matter to this office.

Very truly yours, 8309300285 830923

{DRADOCK 05000454 PDR k , [, 4ta^

T. R. Tramm Nuclear Licensing Administrator 1m cc: Director Of Inspection and Enforcement ggp16 60 7327N