ML20101F539
| ML20101F539 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 12/07/1984 |
| From: | Counsil W NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| F0637A, F637A, SD-63, NUDOCS 8412270208 | |
| Download: ML20101F539 (2) | |
Text
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L J ",,o",Z "[',',1"". C (203) 665-5000 December 7,1984 Docket No. 50-423 F0637A Dr. Thomas E. Murley Regional Administrator Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
Dear Dr. Murley:
Millstone Nuclear Power Station, Unit No. 3 Reporting of Potential Significant Deficiencies in Design and Construction:
Auxiliary Feedwater Pump Wear Rings (SD-63)
In a November 7,1984 telephone conversation between your Mr. T. Rebelowski and our Mr. A. K. Gulesserian, Northeast Nuclear Energy Company (NNECO) reported a potential significant deficiency in the construction of Millstone Unit No. 3 as required by 10CFR50.55(e).
The potential significant deficiency involved the failure of auxiliary feedwater pump impeller wear rings. Northeast Utilities was notified by Bingham Willamette Company (BWC) that an auxiliary feedwater pump at the Palo Verde Nuclear Generating Station had experienced the failure of the first stage impeller wear ring. BWC stated that the Millstone Unit No. 3 auxiliary feedwater pumps have the identical wear ring design and material (440A spuncast) as the Palo Verde pumps.
The f ailure of an impeller wear ring would most likely result in a degradation of performance for the affected stage. The presence of metal fragments in the flow path caused by the failure could potentially affect other stages within the pump by restricting the discharge flowpath. This could lead to a reduction or loss of pumping capacity such that coincident with a postulated single f ailure in the auxiliary feedwater system, the system's ability to remove core sensib;e and decay heat could be adversely impacted. A common cause failure of impeller wear rings on multiple pumps could also adversely impact the system's ability to perform its intended function. Because of the similarity between the Millstone Unit No. 3 and Palo Verde pumps, we consider this to be a significant deficiency.
BWC has agreed to repair the impeller wear rings. Corrective action will include the replacement of auxiliary feedwater pump impeller wear rings, throttle sleeves, and bushings with components fabricated from AISI 420 wrought material. All three auxiliary feedwater pump rotors have already been shipped g%
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to BWC for material replacement and are expected back for reinstallation by the end of this year.
We consider this to be our~ final report closing out SD-63. We trust that the above information satisfactorily responds to your concerns.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY W. G.'Counsil Senior Vice President ec:
Mr. R. C. DeYoung, Director Division of Inspection and Enforcement i.
U. S. Nuclear Regulatory Commissicn Phillips Building 7920 Norfolk Avenue Bethesda, MD 20014 4
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