ML20198D063

Significant Deficiency Rept SD-26 Re Potential for Undetectable Failure in Online Testing Circuits within Westinghouse Solid State Protection Sys.Initially Reported on 820804.Circuit Mod Obviates 820910 Testing Commitment

ML20198D063
Person / Time
Site:	Millstone
Issue date:	10/21/1985
From:	Opeka J NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
F0877A, F877A, SD-26, NUDOCS 8511120257
Download: ML20198D063 (3)

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HARTFORD. CONNECTICUT 06141-0270 k k J CE3C',Cg", (203) 665-5000 October 21,1985 Docket No. 50-423 F0377A Dr. Thomas E. Murley Regional Administrator U. S. Nuclear Regulatory Commission Region 1 631 Park Avenue King of Prussia, PA 19406

Reference:

(1) W. G. Counsil letter to R. C. Haynes, B10560, dated September 10,1932.

Dear Dr. Murley:

Millstone Nuclear Power Station, Unit No. 3 Reporting of Potential Significant Deficiencies in Accordance with 10CFR50.55(e): Solid State Protection System - Undetectable Failure (SD-26)

In an August 4,1932 telephone conversation between your Mr. L. Briggs and our Mr. R. Lefebvre, Northeast Nuclear Energy Company (NNECO) reported a potential significant deficiency in the construction of Millstone Unit No. 3 in accordance with 10CFR50.55(e). This potential significant deficiency involved an undetectable failure which could exist in the on-line testing circuits for relays within the Westinghouse solid state protection system.

In Reference (1), NNECO determined this to be a significant deficiency.

Additionally in Reference (1), NNECO committed to implement the Westinghouse recommended test procedures revision which would assure that such a failure could not go undetected.

Although no design changes were deemed necessary at the time to resolve safety concerns, Westinghouse undertook a design review of the matter in the interest of prudent engineering.

Subsequently, Westinghouse sent (FCN-NEUM-10558) Field Change Notice to NNECO recommending a design change to the SSPS system. This design change modified the SSPS output relay test panel to insure detection of a potentially undetectable test circuit failure. NNECO implemented the design change and installed the change per the FCN. Once the change was installed, the circuit was tested in accordance with the SSPS technical manual.

This minor circuit modification obviated the need for the special testing described in Ref. (1).

8511120257 851021 PDR ADOCK 05000423 1 S PDR IOc x1

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The purpose . of this update is to delete the . testing commitment noted in Reference 1 and report the incorporation of the above described modification.

i We consider this information sufficient to close this issue.

! Very truly yours, I

NORTHEAST NUCLEAR ENERGY COMPANY  ;

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J. F. Opekd" i Senior Vice President i

- cc: Mr. J. M. Taylor, Director ,

Division of Inspection and Enforcement J~

U. S. Nuclear Regulatory Commission Washington, D. C. 20555 i

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