ML20091J316

Significant Deficiency Rept SD-52 Re Deformation of Copper Nickel Pipes in Vicinity of Carbon Steel Trunnions Resulting in Attachment Weld Leaks During Tests.Initially Reported on 830606.Final Rept by 841016

ML20091J316
Person / Time
Site:	Millstone
Issue date:	05/22/1984
From:	Counsil W NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
F0511A, F511A, SD-52, NUDOCS 8406050471
Download: ML20091J316 (2)

Text

a General Offices

• Seiden Street, Berlin, Connecticut 5 ~~ P.O. BOX 270 CM7 cot, HARTFORD, CONNECTICUT 06141-0270 g J amm unni ence cow- (203) 666-6911 w w w w .nonaa m .

May 22,1984 Docket No. 50-423 F0511 A Dr. Thomas E. Murley Regional Administrator Region I U. S. Nuclear Regulatory Commission 631 Park Avenue

' l'ing of Prussi% PA 19406

Reference:

(1) W. G. Counsil letter to T. E. Murley, F0489A, dated March 7, 1984.

Dear Dr. Murley:

Millstone Nuclear Power Station, Unit No. 3 Reporting of Potential Significant Deficiencies in Design and Construction: Service Water Pipe Trunnions (SD-52)

In a February 6,1984 telephone conversation between your Mr. T. Elsasser and our Mr. R. W. Vogel, 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 fabrication of integral welded carbon steel trunnions to copper nickel piping in the Service Water System. Deformation of the copper nickel pipes in the vicinity of the carbon steel trunnions was observed. Two attachment weldments leaked during hydrostatic tests.

Our architect-engineer, Stone and Webster Engineering Corporation, and our engineering staff are in the process of performing an evaluation of this potential significant deficiency. Although not complete at this time, the evaluation has shown that certain trunnion attachments have deformed the pipe during welding to the extent that replacement is necessary. The status to date is as follows:

1. Twenty-seven (27) supports with trunnion attachments were installed in the Service Water System at Millstone Unit No. 3. Initial evaluation found problems with pipe deformation in several installations and possible reduction in corrosion protection on some piping where access to pipe internals was possible. All installed trunnion attachments will be replaced.

2. Design review shows nineteen (19) supports with trunnion attachments that have not yet been installed. In order to avoid f urther complications in field welding, all of there supports will be redesigned.

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3. The redesign has eliminated supports with trunnion attachments where possible and replaced other trunnion attachments with non-integral support designs. In cases where welded trunnion supports are still required, carbon steel trunnions will be replaced with copper-nickel trunnions.

Of the total of forty-six (46) trunnion supports that had been previously designed,

• N eighteen (18) supports were eliminated, three (3) supports were replaced with non-integral support designs, and twenty-five (25) supports require copper-nickel

.: trunnions. All of these supports have been redesigned.

E' Based 'on a telephone conversation between your Mr. T. Rebelowski and our

. Mr. R. R. Viviano, this report is being provided to you on May 22, 1984 rather than May 15, 1984. We will provide you with a final report on this matter by

' - October 16,1984.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY ff/< h W. G. Counsil' Senior Vice President cc: Mr. R. C. DeYoung, Director Division of Inspection and Enforcement U. S. Nuclear Regulatory Commission Phillips Building 7920 Norfolk Av-nue Bethesda, MD 20014 t

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