ML20083R420

Final Significant Deficiency Rept SD-46 Re Potential Defective Springs on Pacific Scientific Mechanical Snubbers.Initially Reported on 831018.Deficiency Not Reportable Per 10CFR50.55(e)

ML20083R420
Person / Time
Site:	Millstone
Issue date:	04/13/1984
From:	Counsil W NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
F0448A, F448A, SD-46, NUDOCS 8404240132
Download: ML20083R420 (2)

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General Offices

• Selden Street Bertin, Ccnnecticut n E N E Ye = cU.~= HARTFORD. CONNECTICUT 06141-0270

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April 13,1984 Docket No. 50-423 F0448A 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, B10970, dated December 6, 1983.

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

Potential Defective Spr ings on Pacific Scientific Mechanical Snubbers (SD-46)

In an October 18, 1983 telephone conversation between your Mr. 3. Robertson and our Mr. R. E. Lefebvre, 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 involves broken and cracked tangs on capstan springs used on Pacific Scientific size 1 and 3 mechanical snubbers.

A site review by our architect-engineer, Stone & Webster Engineering Corporation, identified 181 units with potential spring deficiencies which were returned to the vendor for inspection. Of the 181 units inspected, 86 had microcrack indications in their springs which were subsequently replaced.

The vendor has performed testing on snubbers with microcrack indications and has concluded that these snubbers would have performed their safety function for the 40-year design life. Based on this testing, NNECO concludes that if the cracked springs had gone undetected, the safety function of the Category I systems associated with these snubbers would not have been compromised.

Therefore, this topic is not considered to be a significant deficiency with respect to 10CFR50.55(e).

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As such, we consider this to be our final report on SD-46. Based on a February 3, 1984 telephone conversation between your Mr. . T. Elsasser and our Ms. P.

Capello-Bandzes, and a March 30,1984 conversation between your Mr. T.

Rebelowski and our Mr. R. E. Lefebvre, this report is being provided to you by j April 16,1984. We trust that the above information satisf actorily responds to

] your concerns.

4 Very truly yours, f NORTHEAST NUCLEAR ENERGY COMPANY l

Af/Adt' '

W.'G. Cou6sil

Senior V.ce President i,

cc: Mr. R. C. DeYoung, Director Division of Inspection and Enforcement U.S. Nuclear Regulatory Commission l Phillips Building j 7920 Norfolk Avenue j Bethesda, MD 20014 1

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