ML20084K019

Final Deficiency Rept 83-07 Re Reactor Coolant Pump Bearing Failure.Initially Reported on 830505.Metallurgical Exam of Damaged Bearing Components Revealed No Evidence of Matl or Process Deficiencies

ML20084K019
Person / Time
Site:	Byron
Issue date:	05/02/1984
From:	Tramm T COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
8257N, 83-07, 83-7, NUDOCS 8405110070
Download: ML20084K019 (2)

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( '7 Address Reply to: Post Office Box 767 j Chicago, filinois 60690 May 2, 1984 Mr. James G. Keppler Regional Administrator 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

, References (a): June 9, 1983 leller from E. D. Swartz to J. G. Keppler.

(b): September 23, 1983 letter from T. R.

Tramm to J. G. Keppler.

Dear Mr. Keppler:

This letter provides the final report on the failure 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. References (a) and (b) provided interim reports of the analysis of this event. For NRC tracking purposes, this deficiency is numbered 83-07.

Metallurgical examination of the damaged bearing components has been completed. Westinghouse performed standard metallography and hardness characterizations, emission spectroscopy, standard chemical analysis, electron microscopy and surface analyses evalua-tions. These evaluations revealed no evidence of material or process deficiencies. They demonstrated that silica sand was present in the remelted metallic debris as well as on the scored surface of the rotor journal. Because no other evidence of a failure mechanism has been identified we conclude that introduction of sand particles into i the bearing annulus caused scoring which lead to complete surface destruction.

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H. R..Denton May 2, 1984 .

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L The source of the containment sand is not know. Only one  !

of four pumps failed. It failed after operating over 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />  :

with no apparent difficulties. Plant cleaning procedures and .  !

filtering systems appear to be adequate. We will keep you advised  !

of further problems of this type. I l I l Please address further questions regarding this matter to - ;

! this of fice.  !

Very truly yours, l' t

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T. R. Tramm Nuclear Licensing Administrator ,

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cc: Director of Inspection and Enforcement i Resident Inspector - Byron  !

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