ML17083C404

Forwards Nonproprietary WCAP-13038 & Proprietary WCAP-13039, Technical Justification for Eliminating Large Primary Loop Pipe Rupture as Structural Design Basis For.... Proprietary WCAP-13039 Withheld (Ref 10CFR2.790)

ML17083C404
Person / Time
Site:	Diablo Canyon
Issue date:	03/16/1992
From:	Rueger G PACIFIC GAS & ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML16341G488	List: ML16341G487 ML17083C404 ML17083C405
References
DCL-92-059, DCL-92-59, NUDOCS 9203230334
Download: ML17083C404 (6)

Text

ACCELERATED DISTRIBUTION

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ACCESSION NBR:9203230334 DOC.DATE: 92/03/16 NOTARIZED: YES DOCKET FACIL:50-275 Diablo Canyon Nuclear Power Plant, Unit 1, Pacific Ga 05000275 50-323 Diablo Canyon Nuclear Power Plant, Unit 2, Pacific Ga 05000323 AUTH. NAME AUTHOR AFFII IATION RUEGER,G.M. Pacific Gas & Electric RECIPIENT AFFILIATION Cc. g~ &~-/Pygmy/ y g+~ /g-)3+/'ECIP.NAME Document Control Branch (Document Control Desk)

SUBJECT:

Forwards nonproprietary WCAP-13038 & proprietary WCAP-13039, "Technical Jusitification for Eliminating Large Primary Loop Pipe Rupture as Structural Design Basis for...." Proprietary WCAP-13039 withheld (ref 10CFR2.790).

DISTRIBUTION CODE: RPOID TITLE: Proprietary Review COPIES RECEIVED:LTR Distribution J ENCL /

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RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 ROOD,H 3 3 INTERNAL: ACRS 6 6 AEOD DO+ 1 1 OGC/HDS1 1 0 1 1 EXTERNAL: NRC PDR NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WAS'ONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

Pacific Gas and Electric Company 77 Scale Street Gregory M. Rueger San Francisco, CA 94106 Senior Vice President and 415/973-4684 General Manager Nuclear Power Generation March 16, 1992 PG&E Letter No. DCL-92-059 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Re: Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 Transmittal of WCAP-13039 and WCAP-13038 Gentlemen:

Enclosed for your review are copies of WCAP-13039 (proprietary) and WCAP-13038 (non-proprietary), "Technical Justification for Eliminating Large Primary Loop Rupture as the Structural Design Basis for the Diablo Canyon Units 1 and 2 Nuclear Power Plants," dated November 1991.

This report provides the "leak-before-break" (LBB) evaluation of the reactor coolant loop piping and contains the technical basis for the elimination of the dynamic effects associated with postulated primary loop pipe ruptures from the design basis for Diablo Canyon, as permitted by the revised General Design Criterion 4 (GDC-4) of Appendix A to 10 CFR 50.

Westinghouse has successfully applied LBB methodology for the primary loops in over 30 plants. The LBB evaluation follows the guidelines of Standard Review Plan Section 3.6.3, "Leak-Before-Break Evaluation Procedure." The Diablo Canyon reactor coolant pressure boundary leakage detection system is described in FSAR Update Section 5.2.7. It was reviewed and accepted by the NRC and found to conform with the functional requirements and detection capabilities recommended in Regulatory Guide 1.45 (see Diablo Canyon Safety Evaluation Report Section 5.2.7, October 16, 1974).

PG&E requests approval of this report, which will eliminate the dynamic effects of postulated primary loop pipe ruptures from the design basis of Diablo Canyon. Specifically, the following breaks are eliminated: the six terminal ends in the cold, hot, and crossover legs; a split in the steam generator inlet elbow; and the loop closure weld in the crossover leg. Approval of this report will not affect the containment design basis, the design basis for ECCS, nor environmental qualification of

'quipment.

NRC approval of this report will allow the removal of affected whip restraints and jet impingement shields, which will increase accessibility, decrease inservice inspection personnel radiation doses, and improve maintenance. Also, pending NRC approval, the FSAR Update will be amended to reflect the revised design basis as a result of implementing LBB methodology.

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Document Control sk March 16, 1992 PGKE Letter No. DCL-92-059 As WCAP-13039 contains information proprietary to Westinghouse Electric Corporation, it is supported by an affidavit signed by Westinghouse, the owner of the information. The affidavit sets forth the basis on which the information may be withheld from public disclosure by the NRC and addresses, with specificity, the considerations listed in 10 CFR 2.790(b)(4).

Accordingly, included in the enclosures is Westinghouse Letter CAW-92-257, "Application for Withholding Proprietary Information from Public Disclosure,"

dated January 24, 1992, containing Affidavit CAW-92-257, a Proprietary Information Notice, and a copyright notice. It is respectfully requested that the information proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CFR 2.790.

Correspondence regarding the proprietary aspects of the Application for Withholding or the supporting Westinghouse affidavit should reference CAW-92-257 and should be addressed to R. P. Di Piazza, Manager, Nuclear Safety Licensing, Westinghouse Electric Corporation, P.O. Box 355, Pittsburgh, Pennsylvania 15230-0355.

Sincerely,

~JL Gregory H. Rueger Enclosures cc: Ann P. Hodgdon John B. Hartin (w/enc.)

Philip J. Horrill Harry Rood Howard J. Wong CPUC Diablo Distribution 5609S/85K/HWZ/1841