ML20129H529

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Forwards Value Impact of Implementing Leak-Before-Break & Elimination of Associated Pipe Whip Restraints & Jet Deflectors on RCS Primary Loop, to Support Partial Exemption from GDC-4
ML20129H529
Person / Time
Site: Byron, Braidwood, 05000000
Issue date: 06/28/1985
From: Ainger K
COMMONWEALTH EDISON CO.
To: Harold Denton
Office of Nuclear Reactor Regulation
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ML20129H533 List:
References
0295K, 295K, NUDOCS 8507190226
Download: ML20129H529 (2)


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Commonwealth Edison t ) One First Nabonal Ptm Chicago. Ilknois

( Address Reply to: Post Office Box 767

- Chicago, Illinois 60690 June 28, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 Elimination of Postulated Pipe Breaks in the RCS Primary Loops NRC Docket Nos. 50-454, 50-455, 50-456 and 50-457 Reference (a): September 17, 1984 letter from E. D.

Swartz to H. R. Denton. g 4

\* i

Dear Mr. Denton:

\

Reference (a) provided the technical justification for applying the leak-before-break concept to the reactor coolant system (RCS) primary loops 4 at Byron and Braidwood stathos. This concept eliminates postulated pipe breaks from the design basis of the RCS primary loops and is the basis for the partial exemption from General Design Criterion (GDC) 4 that was 4 requested in reference (a). In addition to the technical information y provided in reference (a), a value impact analysis has been performed to support granting the partial exemption.

Enclosed ir the value impact analysis, in terms of man-rem exposure, for implementing the leak-before-break concept to eliminate pipe whip restraints and jet deflectors on the Byron and Braidwood RCS primary loops.

Although Byron Unit 1 is operating in compliance with the requirements of GDC-4, our value impact analysis demonstrates a man-rem savings over this unit's 40-year life by removing the installed pipe whip restraints and jet deflectors at the earliest opportunity.

It is our understanding that the tRC is now pursuing a change to GDC-4 thrnugh the rulemaking process. Therefore, Commonwealth Edison requests a partial exemption from GDC-4 be granted for the first two fuel cycles of each Byron and Braidwood unit.

()yh 0507190226 050620 '\ I i PDR ADOCK 05000454 3 P PDR

. - _______ ____ _ __ ______ _________________ _.___._ f

H. R. Denton June 23, 1985 One signed original and fifteen ccpies of this letter and enclosure are provided for NRC review.

Please direct any questions regarding this matter to this office.

Very truly yours, K. A. Ainger Nuclear Licensing Administrator 1m Enclosure cc: Byron Resident Inspector Braidwood Resident Inspector 9

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