ML20093M778

Final Significant Deficiency Rept SD-58 Re Overpressure Condition in Westinghouse Component Cooling Water Sys. Initially Reported on 840713.Item Not Reportable Per 10CFR50.55(e)

ML20093M778
Person / Time
Site:	Millstone
Issue date:	09/25/1984
From:	Counsil W, Sears C NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
F0595A, F595A, SD-58, NUDOCS 8410230270
Download: ML20093M778 (2)

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General Offices

• Selden Street, Berlin. Connecticut 3 $' '5 m ** P.O. BOX 270 HARTFORD. CONNECTICUT 06141-0270 L L J **"*'**"""",%~,,

Z [2 (203) 66s-s000 September 25,1984 Docket No. 50-423 F0595A Dr. Thomas E. Murley Regional Administrator Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406

Reference:

(1) W. G. Counsil to T. E. Murley, F0586A, dated August 10, 1984.

Dear Dr. Murley:

Millstone Nuclear Power Station, Unit No. 3 i Reporting of Potential Significant Deficiencies in Design and Construction:

Potential for Overpressure Condition in Westinghouse Component Cooling Water System (SD-58_1 In a July 13, 1984 telephone conversation between your Mr. T. Rebelowski and our Mr. R. R. Viviano, Northeast Nuclear Energy Company (NNECO) reported a potential significant deficiency in the design and construction of Millstone Unit No. 3 as required by 10CFR50.55(e). The potential significant deficiency involves component cooling water systems designed by Westinghouse. There is a potential for an overpressure condition in Westinghouse component cooling water systems resulting from the automatic closure of the surge tank vent valve on a high radiation signal from the component cooling water system radiation monitor.

As committed in Reference (1), we have completed our review of the Millstone Unit No. 3 component cooling water system which was designed by Stone &

Webster Engineering Corporation to determine whether or not this condition could exist in the Millstone Unit No. 3 design. Millstone Unit No. 3 does not have valves on the surge tank vent line. Therefore, without some means of blocking the vent line, overpressurization of the component cooling water system could not occur. Hence, this is not a significant deficiency for Millstone Unit No.3.

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We consider this to be our final report closing out SD-58. We trust that .this

-Information satisfactorily responds to your concerns. .

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY W .Gr .D W. G. Counsil Senior Vice President By: C. F. Sears Vice President cc: Mr. R. C. DeYoung, Director Division of Inspection and Enforcement U. S. Nuclear Regulatory. Commission Phillips Building 7920 Norfolk Avenue :

Bethesda, MD 20014

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