ML19260C327

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Submits Addl Info for Proposed Tech Spec Amend 27 Re LOCA- ECCS Calculation for Small Break Using Nonheatup Rate Dependent Burst Curve
ML19260C327
Person / Time
Site: North Anna  Dominion icon.png
Issue date: 12/19/1979
From: Stallings C
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To: Harold Denton, Schwencer A
Office of Nuclear Reactor Regulation
References
986B, NUDOCS 7912260209
Download: ML19260C327 (2)


Text

3 VIRGINEA ELECTHIC AND Powzu Cour.wy Rrcumonn,Vzno MIA nO261 December 19, 1979 Mr. Harold R. Denton, Director Serial No.: 986B Office of Nuclear Reactor Regulation FR/MLB: mvc Attn: Mr. A. Schwencer, Chief Operating Reactors Branch No. 1 Docket No.: 50-338 Division of Operating Reactors 50-339 U. S. Nuclear Regulatory Commission Washington, DC 20555 License No.: NPF-4 SUPPLEMENTAL INFORMATION TO AMENDMENT TO OPERATING LICENSE NPF-4 NORTH ANNA POWER STATION UNITS NO.1 AND 2 PROPOSED TECHNICAL ' SPECIFICATIONS 'CIWIGE NO. 27 My letter to you dated November 29, 1979, Serial No. 986, transmitted our proposed Technical Specifications Change No. 27 and a supporting LOCA-ECCS analysis which met the limits of 10 CFR 50.46. This analysis was determined to be in compliance with Appendix K to 10 CFR 50 even though the' cladding heatup rate dependent burst curve used was revised and had not been explicitly reviewed by the B:RC. This approach was taken because the revised modeling was more technically correct. To facilitate the NRC staff review and understanding of this revision, we are providing, as supplemental information. to our transmittal of November 29, 1979, a LOCA-ECCS calculation for the C = 0.4 DECLG break (limitingbreaksize)usingthenon-heatupratedependektburstcurvemodeling documented in the February 1978 version of the Westinghouse ECCS Evaluation Model.

This calculation resulted in a peak clad temperature of 2088 F.

Both the analysis provided in our November 29, 1979 submittal and the above analysis meet the criteria denoted in 10 CFR 50.46. However, as indicated in the Westinghouse (T. M. Anderson) to NRC (D. G. Eisenhut) letter of December 7, 1979 (Serial No. NS-TMA-2174), additional impacts on the limiting peak clad

. temperature may result if the flow blockage modeling documented in draf t report NUREC 0630 (reference NRC (D. B. Vassalo) letter of November 28, 1979) is used.

At this time, we do not believe that these potential impacts will be significant when the NRC review is completed. Further, these potential impacts can be offset by the modeling improvements documented by Westinghouse in their above letter of December 7, 1979. These benefits are expected to more than offset any potential impacts on North Anna 1 & 2 even if implementation of the current version of draf t report NUREG-0630 is required. As a result, the reduction in the limiting F valuesasproposedinourrequestedTechnicalSpecificationsJhangeNo.27rkmains appropriate for supporting continued operation.

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visoixu EuerEIC AND Powra CoxPAxv To Mr. Harold R. Denton 2 Should you have questions, please coatact our Mr. M. L. Bowling (804-771-3183) at your earliest convenience.

Very truly yours,

. . dlY

.C. M. Stallings Vice President-Power Supply and Production Operations cc: Mr. James P. O'Reilly, Director Office of Inpsection and Enforcement, Region II Mr. O. D. Parr, Chief Light Water Reactors Branch No. 3 Mr. J. E. Rosenthall, Reactor Safety Branch Division of Operating Reactors 1616 360