ML20107G098

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Forwards Proprietary Technical Bases for Eliminating Large Primary Loop Pipe Rupture as Structural Design Basis for Beaver Valley..., to Resolve Unresolved Safety Issue A-2, Asymmetric LOCA Loads. Rept Withheld (Ref 10CFR2.790)
ML20107G098
Person / Time
Site: Beaver Valley
Issue date: 02/19/1985
From: Sieber J
DUQUESNE LIGHT CO.
To: Varga S
Office of Nuclear Reactor Regulation
Shared Package
ML19269B099 List:
References
REF-GTECI-A-02, REF-GTECI-RV, TASK-A-02, TASK-A-2, TASK-OR NUDOCS 8502260304
Download: ML20107G098 (3)


Text

'Af Telephone (412) 3934000 gr civision Shippingport, PA 150U4004 February 19, 1985 Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Attn: Mr. Steven A. Varga, Chief Operating Reactors Branch No. 1 Division of Licensing Washington, DC 20555

Reference:

Beaver Valley Power Station, Unit No.1 Docket No. 50-334, License No. DPR-66 Leak-Before-Break Analysis Gentlemen:

In our July 31, 1984 letter we informed you of our intent to perfonn an evaluation to justify a leak-before-break position in order to resolve Unresolved Safety Issue A-2, " Asymmetric LOCA Loads," for Beaver Valley Unit 1. This evaluation has been completed and enclosed for your review are:

1. Five (5) copies of " Technical Bases for Eliminating Large Primary Loop Pipe Rupture as a Structural Design Basis for Beaver Valley Unit 1," dated December 1984, WCAP-10743 (Proprietary).
2. Five (5) copies of " Technical Bases for Eliminating Large Primary Loop Pipe Rupture as a Structural Design Basis for Beaver Valley Unit 1," dated December 1984, WCAP-10742 (Non-proprietary).

Also enclosed is a Westinghouse authorization letter, CAW-84-106, and accompanying affidavit.

Item 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 infonnation which is proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CFR Section 2.790 of the Commission's regulations. Cor-respondence with respect to the proprietary aspects of the. Application for Withholding or the supporting Westinghouse affidavit should reference CAW-84-106, and should be addressed to R. A. Wiesemann, Manager, Regulatory

-& Legislative Affairs, Westinghouse Electric Corporation,' P.O. Box 355, Pittsburgh, PA 15230. O J

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February 19, 1985 Beaver Valley Power Station, Unit No.1 Docket No. 50-334, License No. DPR-66 Leak-Before-Break Analysis Page 2 Included in WCAP-10743 is a discussion of the effects of thermal aging on the material toughness for the primary loop piping. From this review we have detemined that the predicted end-of-life toughness for some of the material heats used in the primary loop piping does not meet the current Westinghouse toughness criteria to justify a leak-before-break analysis until end of life. However, we are able to justify a leak-before-break posi-tion for Beaver Valley Unit 1 for 11.7 years at operating temperature since all of the piping will exceed the Westinghouse toughness criteria for. this period of operation.

We have calculated the cumulative themal aging time for Beaver Valley Unit 1 primary loop piping as of December 31, 1984. As of this time, 5.24 years of themal aging have occurred. This number is conservatively based on the time above 200 F (Mode 5). Therefore, as of January 1, 1985, 6.46 years at operating temperature remain before Beaver Valley Unit I limiting material heat reaches the toughness criteria.

Only a limited amount of testing of themally aged material has been perfomed at this time. Therefore, only a limited database presently exists-which does not envelop all of the existing material heats in service.. Since the Westinghouse toughness criteria are based on the limited database, they.

also do not envelop all of the existing material heats in service, . including some material heats used at Beaver Valley Unit 1. We are currently review-ing possible actions'to resolve the thermal aging . concerns for Beaver Valley Unit 1 and will inform you of our plans in future correspondence.

If you have any questions concerning this. matter, please contact my office.

Very truly 'yours', .

. b J. D. Sieber-Senior Manager y '

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t February 19, 1985 Beaver Valley Power Station, Unit No.1 Docket No. 50-334, License No. DPR-66 Leak-Before-Break Analysis Page 3 P

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Mr. W. M. Troskoski, Resident Inspector U.S. Nuclear _ Regulatory Commission Beaver Valley Power Station Shippingport, PA 15077 U.S Nuclear Regulatory Commission c/o Document Management Branch Washington, DC 20555 Mr. Peter Tam, Project Manager U.S. Nuclear Regulatory Commission

-Phillips Building-Washington, DC 20555

-Mail Stop 438-

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