ML20197G891
| ML20197G891 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 06/08/1984 |
| From: | Counsil W NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| F0520A, F520A, SD-47, NUDOCS 8406180195 | |
| Download: ML20197G891 (2) | |
Text
1 General Offices e Seiden Street, Berlin, Connecticut 5
P.O. BOX 270 C E.)'*,, **
HARTFORD. CONNECTICUT 06141-0270
.se w cow (203) 666-6911 g
June 8,1984 Docket No. 50-423 F0520A 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 letter to T.
E.
Murley, F0429A, dated December 9,1983.
(2)
W. G. Counsil letter to T. E. Murley, F0449A, dated March 9, 1984.
Dear Dr. Murley:
Millstone Nuclear Power Station, Unit No. 3 Reporting of Potential Significant Deficiencies in Design and Construction:
Seismic Duct Welds Potentially Underdesigned (SD-47)
In a November 9,1983 telephone conversation between your Mr. T. Usasser 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(c). The potential significant deficiency involves duct weld joints which may be underdesigned with respect to seismic requirements.
This was the result of inconsistent interpretation of weld symbols between the duct fabricator and the architect-engineer. This resulted in partial penetration welds rather than full penetration welds which was specified by the duct designer.
Our architect-engineer, Stone & Webster Engineering Corporation, conducted a test program on weld strength and inspected a random sample of existing welds.
Calculations were performed for required weld strength and it was determined that the as-built weld penetrations for square groove butt welds in this ductwork will provide strengths well in excess of base material or design limit values. Our engineering staff has reviewed these calculations and concurs with their conclusion.
Based on this, we have determined that no corrective action is necessary and do not consider this to be a significant deficiency.
8406180195 840608 PDR ADOCK 05000423 G
PDR l
I D li Nl
. We consider this to be our final report regarding SD-47. We trust that this information satisfactorily responds to your concerns.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY 4
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 Avenue Bethesda, MD 20014 i
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