ML20138K840

Final Part 21 & Deficiency Rept SD-41 Re Gould Type He 4 100-amp Frame Size Breaker in 480-volt Motor Control Ctr Which Failed When Pole C Did Not Close When Breaker Operated.Initially Reported on 830608.Breakers Replaced

ML20138K840
Person / Time
Site:	Millstone
Issue date:	12/03/1985
From:	Mroczka E, Opeka J NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
REF-PT21-85, REF-PT21-86-007-000 F0930A, F930A, PT21-86-007-000, PT21-86-7, SD-41, NUDOCS 8512190092
Download: ML20138K840 (2)

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HAR TFORD. CONNECTICUT 06141-0270 k k J (( [] j,] ", (203) 665-5000 December 3,1985 Docket No. 50-423 F0930A Dr. Thomas E. Murley Regional Administrator U.S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406

Reference:

(1) W. G. Counsil letter to T. E. Murley, B10837, dated July 8, 1933.

Dear Dr. Murley:

Millstone Nuclear Power Station, Unit No. 3 Reporting of Potential Significant Deficiencies in Accordance with 10CFR 50.55(e): Gould Type HE 4 Breakers (SD-41)

In a June 8,1983 telephone conversation between your Mr. T. Elsasser and our Mr. R. E. 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).

The potential significant deficiency involved a Gould Type HE 4100 amp frame-size breaker in a 480 V Motor Control Center which failed when the "C" pole did not close when the breaker was operated. Three-phase loads will not operate if one pole of the supply is open. As noted in Reference (1) this potential significant deficiency was held open pending the results of our investigation into this matter.

Gould notified NNECO that an Advisory Notice of Part Potential Product Defect had been transmitted to the NRC pursuant to 10CFR21. Gould had determined that the potentially defective breakers can be identified by date code. The effected date codes run from November 1,1981 to February 16, 1982.

To correct this problem, all Gould Type HE 4100 ampere frame-size breakers were inspected and those found with date codes f alling within the time interval of November 1,1981 to February 16, 1982 were considered suspect and replaced.

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t We consider this to be our final report for SD-41. We trust that the above  ;

information satisfactorily responds to your concerns. t Very truly yours, .

I NORTHEAST NUCLEAR ENERGY COMPANY JE0%

3. F. Opeka Senior Vice President  !

By: E. 3. f) fro'czka []

l Vice Presdent 4

cc: Mr. 3. M. Taylor, Director j Division of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C. 20555 e

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