ML20214P477

Forwards SER Re TMI Action Item II.K.3.31, Compliance W/ 10CFR50.46, Per Util 850725 & s Ref WCAP-11145, Westinghouse Small Break LOCA ECCS Evaluation Model Generic Study.... Calculations Conservative.Action Complete

ML20214P477
Person / Time
Site:	North Anna
Issue date:	11/21/1986
From:	Engle L Office of Nuclear Reactor Regulation
To:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
References
TASK-2.K.3.31, TASK-TM GL-83-35, NUDOCS 8612040232
Download: ML20214P477 (4)

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> November 21, 1986 ,

I Docket Nos. 50-338~ D T ION and 50-339 4

• L. Engle NRC PDR D. Miller Local PDR ACRS (10)

Mr. W. L. Stewart, Vice President PAD #2 Rdg Tech Branch Nuclear Operations T. Novak Virginia Electric and Power Company OGC-Bethesda Post Office Box 26666 E. Jordan Richmond, Virginia ~ 23261 8. Grimes J. Partlow

Dear Mr. Stewart:

N. Thompson, DHFT By letters dated July 25, 1985, and July 25, 1986, you responded to TMI Action Plan Item II.K.3.31, " Compliance with 10 CFR 50.46" by referencing WCAP-11145,

" Westinghouse Small Break LOCA ECCS Evaluation Model Generic Study with the NOTRUMP code." The topical report demonstrates that the small break LOCA calculations in the North Anna FSAR are conservative in comparision to the NOTRUMP evaluation model calculations. This is the requirement of NRC Generic Letter 83-35 for compliance with Action Item II.K.3.31. Staff review of WCAP-11145 has been completed. Our Safety Evaluation for the North Anna Units is enclosed.

This completes our actions on this item. Since the North Anna Units are already .;

in compliance with 10 CFR 50.46, no additional requirements or schedular implementation dates are required.

Sincerely, Leon B. Engle, Pro.iect Manager PWR Pro.iect Directorate #2 Division of PWR Licensing-A

Enclosure:

As stated cc: See next page LA 2 PM: PD:P 0#2 DMiller LEngle:he LRubertstein 11/20/86 11/2C/86 11/'y/86 8612040232 861121 PDR ADOCK 05000338 P PDR

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Mr. W. L. Stewart North Anna Power Station l Virginia Electric & Power Company ' Units 1 and 2 ,

CC: .

Richard M. Foster, Esq. Atomic Safety and Licensing Appeal l Cockrell, Quinn & Creighton Board Panel 1 516 Cherry Tower U.S. Nuclear Regulatory Commission 920 South Cherry Street. Washington, DC 20555 Denver, Colorado 80222 Regional Administrator, Region II Michael W. Maupin, Esq. U.S. Nuclear Regulatory Commission Hunton, Williams, Gay and Gibson Office of Executive Director P. O. Box 1535 for Operations Richmond, Virginia 23212 101 Marietta Street N.W., Suite 3100 Atlanta, Georgia 30323 Mr. W. T. Lough ,

Virginia Corporation Commission =Mr. E. W. Harrell Division of Energy Regulation P. O. Box 402 P. O. Box 1197 Mineral, Virginia 23117 Richmond, Virginia 23209 Old Dominion Electric Cooperative Ellyn R. Weiss, Esq. c/o Executive Vice President Harmon, Weiss and Jordan Innsbrook Corporate Center 2001 S Street NW 4222 Cox Road, Suite 102 Washington, DC 20009 Glen Allen, Virginia 23060 Mr. J. T. Rhodes Mr. William C. Porter, Jr.

Senior Vice President - Power Ops. County Administrator Virginia Electric and Power.Co. Louisa County Post Office Box 26666 P. O. Box 160 Richmond, Virginia 23261 Louisa, Virginia 23093

, Mr. Patrick A. O' Hare Office of the Attorney General Supreme Court Ruilding 101 North 8th Street Richmond, Virginia 73219 Resident Inspector / North Anna c/o U.S. NRC Senior Resident Inspector Route 2, Box 78 Mineral, Virginia 23117 Mr. Paul W. Purdom Environmental Studies Institute Drexel University 32nd and Chestnut Streets

! Philadelphia, Pennsylvania 19104 4

/ UNITED STATEc

/' N NUCLEAR REGULATORY COMMISSION

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. ,E WASHINGTON, D. C. 20555

\...../

SAFETY EVALUATION REPORT TMI ACTION PLAN ITEM II.K.3.31 COMPLIANCE WITH 10 CFR 50.46 NORTH ANNA UNITS 1 AND 2 Item II.K.3.30 of NUREG-0737 outlines the Comission requirements for the industry to demonstrate that its small break LOCA methods continue to comply with the requirements of Appendix K to 10 CFR 50. The technical issues to be addressed were listed in NUREG-0611 including comparison with semiscale experimental test results.- In response to Item II.K.3.30, the Westinghouse Owners Group elected to reference the NOTRUMP code as the new licensing small break LOCA model. The NOTRUMP code and methodology are described in WCAP-10079 and WCAP-10054. The staff reviewed and approved NOTRUMP as the new licensing tool for calculating small break LOCA response for Westinghouse plant designs.

The staff further concluded that the Westinghouse Owners Group had met the requirements of Item II.K.3.30.

Referencing the new computer cede did not imply deficiencies in the WFLASH code (which was previously utilized for small break LOCA analysis) such that the code did not comply with Appendix K to 10 CFR 50. The decision to use NOTRUMP was based on desires of the industry to perform licensing evaluations with a computer program specifically designed to calculate small break LOCAs with greater phenomenological accuracy than capable by WFLASH.

Item II.K.3.31 of NUREG-0737 required that each license holder or applicant submit a new small break analysis using the model approved under Item II.K.3.30 NRC Generic Letter 83-35 provided clarification for the II.K.3.31 requirements by allowing license holders and applicants to comply on a generic basis by demonstrating that the WFLASH analyses are conservative when compared to analyses performed using NOTRUMP.

In response to this guidance the Westinghouse owners submitted WCAP-11145, which contains generic comparisons to WFLASH analyses for various plant types. These include comparisons for 3-loop plants of the North Anna design.

If plant specific analyses were perfonned for North Anna using NOTRUMP, lower peak clad temperatures should be expected in comparison with the generic NOTRUMP analysis (about 228 lower than the 1,627*F PCT currently calculated with WFLASH S8LOCA EMI.

Although the calculated peak temperatures are significantly lower for the NOTRUMP analyses than for the WFLASH analyses, the 4 inch break remains the limiting break size.

Staff review of WCAP-1145 has been completed and accepted as a licensing basis for SPLOCA analysis. By letter dated July 25, 1986, the licensee has referenced WCAP-1145 (which consists of the results from calculations using approved methodology) in lieu of submitting a plant specific analysis and meets the i as stated in NRC Generic Letter 83-35. The staff, therefore, concludes

.cr iter a that the North Anna FSAR analyses of small break LOCA have been demonstrated to be conservative in comparison with the NOTRUMP Evaluation Model. This meets the requirements of TMI Action Plan Item II.K.3.31 and 10 CFR 50.46 for North Anna.

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