TXX-4158, Forwards Nonproprietary & Proprietary Topical Rept, Technical Bases for Eliminating Large Primary Loop Pipe Rupture as Structural Design Basis For.... Application for Withholding Encl.Proprietary Rept Withheld (Ref 10CFR2.790)

Forwards Nonproprietary & Proprietary Topical Rept, Technical Bases for Eliminating Large Primary Loop Pipe Rupture as Structural Design Basis For.... Application for Withholding Encl.Proprietary Rept Withheld (Ref 10CFR2.790)

ML20084A674
Person / Time
Site:	Comanche Peak
Issue date:	04/23/1984
From:	Schmidt H TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML19268E843	List: ML20084A677 ML20084A680 TXX-4158, Forwards Nonproprietary & Proprietary Topical Rept, Technical Bases for Eliminating Large Primary Loop Pipe Rupture as Structural Design Basis For.... Application for Withholding Encl.Proprietary Rept Withheld (Ref 10CFR2.790)
References
TXX-4158, NUDOCS 8404250180
Download: ML20084A674 (2)

Text

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Log # TXX-4158 TEXAS UTILITIES GENERATING COMPANY File # 903.6 hKYWAY TE 3WEH

• 100 NipHTII OI,lVE MTHEET I..II. MI

• DAI.I.AM TEXAM 75201 April 23, 1984 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Phillips Building 7920 Norfolk Avenue Bethesda, Maryland 20014

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION DOCKET NOS. 50-445 AND 50-446 ELIMINATION OF LARGE PRIMARY LOOP PIPE RUPTURES REF: a) TUSI Letter No. TXX-4069, dated 10/31/83, Schmidt to Youngblood b) NRC letter to TUGC0 dated 3/2/84, Youngblood to Gary

Dear Mr. Denton:

The reference (a) letter informed the NRC that TUGC0 was evaluating the technical feasibility and potential benefits of eliminating postulated pipe breiks in the RCS primary loop from the structural design basis of the Comanche Peak Units 1 and 2. As part of that letter, Westinghouse reports MT-SME-3135 (and MT-SME-3136), " Technical Bases for Eliminating Large Primary Loop Pipe Ruptures as the Structural Design Basis for Comanche Peak Units 1 and 2," October 1983, Westinghouse Proprietary, were enclosed.

These reports provided the type of information requested by the Staff for NRC review of the technical bases for elimination of RCS primary loop pipe breaks.

The Reference (b) NRC letter indicated that the NRC Staff had reviewed, (1) the leak-before-break analysis provided by the Reference (a) letter, and (2) the generic Westinghouse report WCAP-10456 dealing with fracture toughness of piping materials under thermal aging conditions. As a result of that review, the Materials Engineering Branch requested additional information to complete their evaluation on the subject matter.

At a meeting held March 22, 1984, with repretentatives of the NRC Staff, Texas Utilities, Westinghouse, the responses to the Staff requests for additional information were discussed. At that meeting, the Staff outlined the type of additional'information required by the NRC. The technical information requested is enclosed as follows:

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1. Twenty (20) copies of Westinghouse Report WCAP-10527, " Technical Bases for Eliminating Large Primary Loop Pipe Rupture as the Structural Design Basis for Comanche Peak Units 1 and 2, " April 1984, Westinghouse Proprietary,

2. Twenty (20) copies of Westinghouse Report WCAP-10528, " Technical Bases for Eliminating Large Primary Loop Pipe Rupture as the Structural Design Basis for Comanche Peak Units 1 and 2," April 1984, Non-Proprietary.

Also enclosed is one (1) Application for Withholding, CAW-84-35.

WCAP-10527 is a new report (Proprietary and Non-Proprietary versions as appropriate) prepared specifically for the Comanche Peak Units 1 and 2.

This new report incorporates the previous material in Westinghouse report MT-SME-3135 along with the additional information addressing MEB Items 121.16, 121.17, 121.18 and 121.19. For Item 121.20, an assessment of margins considering the loads, flaw size, and material toughness for the Comanche Peak Units 1 and 2 RCS piping material is also included. Results covering the elastic-plastic fractu.e mechanics analysis of the 4-inch thermally aged pipe in WCAP-10456 is expected to be completed in June 1984 and will be transmitted at that time.

As Enclosure 1 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 Commission and addresses with specificity the considerations listed in paragraph (b)(4) of Section 2.790 of the Commission's regulations.

Accordingly, it is respectfully requested that the information which is proprietary to Westinghouse be withheld from public disclosure in accordance with 10CFR Section 2.790 of the Commission's regulations.

Correspondence with respect to the proprietary aspects of the Application for Withholding or the supporting Westinghouse affidavits should reference CAW-84-35, and should be addressed to R. A. Wiesemann, Manager, Regulatory and Legislative Affairs, Westinghouse Electric Corporation, P.O. Box 355, Pittsburgh, Pennsylvania 15230.

Very truly your,

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• N H. C. Schmidt HCS/grr Attachments