ML20057C465

Discusses Review of Util Setpoint Methodology Using Statistical Combination of Uncertainties,Vol 3, Bases for Uncertainties Included in Statistical Combinations

ML20057C465
Person / Time
Site:	Maine Yankee
Issue date:	09/22/1993
From:	Trottier E Office of Nuclear Reactor Regulation
To:	Frizzle C Maine Yankee
References
NUDOCS 9309280402
Download: ML20057C465 (4)

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WASHINGTON, D.C. 20555-0001 September 22, 1993 Docket No. 50-309 Mr. Charles D. Frizzle, President Maine Yankee Atomic Power Company 83 Edison Drive Augusta, Maine 04336

SUBJECT:

MAINE YANKEE RPS SETPOINT METHODOLOGY USING STATISTICAL COMBINATION OF UNCERTAINTIES, VOLUME 3, " BASES FOR THE UNCERTAINTIES INCLUDED IN THE STATISTICAL COMBINATIONS" t

On April 19, 1988, you submitted Volumes 1 and 2 of your report titled

" Maine Yankee RPS Setpoint Methodology Using Statistical Combination of Uncertainties" for staff review. The staff found this methodology acceptable for use by Maine Yankee, as described in its Safety Evaluation dated September 20, 1990. However, Volumes 1 and 2 of the subject report contained representative values for the uncertainties. Therefore, the staff requested i

that the actual uncertainty values and the justification for their'use--as well as the statistical departure from nucleate boiling ratio (DNBR) limits derived for use in safety related calculations--be provided to the staff prior to the first operating cycle to which the methodology would be applied.

We have received Volume 3 of the subject report, which was enclosed with your letter of transmittal dated July 7, 1993. Volume 3 documents the actual values for the uncertainties, and the distributions and their bases used to derive the final Power to Centerline Melt Specific Acceptable Fuel Design Limit curve fit and statistical DNBR limits. Volume 3 also documents the final statistical DNBR limits developed using the methodology described in Volumes 1 and 2, using the uncertainties defined in Volume 3.

Your letter dated July 7,1993 states that Yankee Atomic Electric Company and Combustion Engineering, Inc. consider Volume 3 proprietary and requests that it be withheld from public disclosure, pursuant to 10 CFR 2.790. Our Office of General Counsel currently is evaluating your request.

You will be advised by letter of the results of that evaluation.

This completes all existing requirements regarding the Maine Yankee RPS Setpoint Methodology Using Statistical Combination of Uncertainties.

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I Mr. Charles D. Frizzle September 22, 1993 Please do not-hesitate to contact me if-you have any questions or require further information on this matter.

i Sincerely, s

Original signed by:

E. H. Trottier, Project Manager Project Directorate I-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation cc:

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Mr. Charles D. Frizzle September 22, 1993 Please do not hesitate to contact me if you have any questions or require further information on this matter.

Sincer y,

'W E. H. Trottier, Project Manager Project Directorate I-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation cc:

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'T Mr. Charles D. Frizzle Maine Yankee Atomic Power Station cc:

Mr. Charles B. Brinkman Manager - Washington Nuclear Mr. James R. Hebert, Manager Operations Nuclear Engineering and Licensing Combustion Engineering, Inc.

Maine Yankee Atomic Power Company 83 Edison Drive 12300 Twinbrook Parkway, Suite 330 Augusta, Maine 04336 Rockville, Maryland 20852 Mr. Robert W. Blackmore Thomas G. Dignan Jr., Esquire Plant Manager Ropes & Gray One International Place Maine Yankee Atomic Power Company P.O. Box 408 Boston, Massachusetts 02110-2624 Wiscasset, Maine 04578 Mr. Uldis Vanags Mr. G. D. Whittier, Vice President State Nuclear Safety Advisor Licensing and Engineering State Planning Office State House Station #38 Maine Yankee Atomic Power Company 83 Edison Drive Augusta, Maine 04333 Augusta, Maine 04336 Mr. P. L. Anderson, Project Manager Mr. Patrick J. Dostie Yankee Atomic Electric Company 580 Main Street State of Maine Nuclear Safety Inspector Bolton, Massachusetts 01740-1398 Maine Yankee Atomic Power Company P. O. Box 408 Regional Administrator, Region I Wiscasset, Maine 04578 U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, Pennsylvania 19406 First Selectman of Wiscasset Municipal Building i

U.S. Route 1 i

Wiscasset, Maine 04578 Mr. J. T. Yerokun Senior Resident Inspector Maine Yankee Atomic Power Station t

U.S. Nuclear Regulatory Commission P. O. Box E Wiscasset, Maine 04578 Mr. Graham M. Leitch Vice President, Operations Maine Yankee Atomic Power Company P.O. Box 408 Wiscasset, Maine 04578 i