ML19246C403

Forwards NRC to Westinghouse Requesting Addl Info Re Small Break LOCA Analyses & Analysis Methods.Nrc Will Eventually Require Documentation Re Applicability of Westinghouse Results to Analyses at Facility

ML19246C403
Person / Time
Site:	Prairie Island
Issue date:	06/11/1979
From:	Schwencer A Office of Nuclear Reactor Regulation
To:	Mayer L NORTHERN STATES POWER CO.
References
NUDOCS 7907240550
Download: ML19246C403 (2)

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JUNE I 1 1979 Docket Nos.50-28L, and'50-306 c

Mr. L. O. Mayer, Manager Nuclear Support Services Northern States Power Company 414 Nicollet Mall - 8th Floor Minneapolis, Minnesota 55401

SUBJECT:

INFORMATION COPY OF REQUEST FOR ADDITIONAL INFORMATION REGARDING WESTINGHOUSE SMALL BREAK LOCA ANALYSIS As we discussed with you during our meeting on May 30, 1979, the NRC staff is evaluating certain aspects of the NRC licensing process in light of the Three Mile Island Unit 2 (TMI-2) accident of March 28, 1979.

One of the aspects being addressed by the staff in its evaluation is the status of the models used in safety analyses, especially with regard to transients and small break LOCAs. Enclosed is a copy of an NRC letter, dated June 4,1979, requesting infomation from your nuclear steam supply vendor, the Westinghouse Electric Corporation, regarding small break 10CA analyses and analysis methods. This enclosure is provided for your infomation.

It is our understanding that you are participating in this effort as it applies to your licensed power plants through an owners group.

At some point in this effort we will require that you document the applicability of the results these Westinghouse analyses to your plants.

To that end, a copy at all correspondence to Westinghcuse and the owners group on this matter will be provided to you and placed in our files on your specific plants.

Please contact P. D. O'Reilly, the staff's assigned proj2ct manager -

for this matter, if you have any questions.

Sincerely, h&eze w

hwencer, Chief A. Sc Operating Reactors Branch #1 Division of Operating Reactors

Enclosure:

NRC June 4,1979 letter to Westinghouse cc: w/enclasures 3b4 2b)

See next page 7 0072.40 @

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JUNE 11 E79 Mr. L. O. Mayer Northern States Power Company cc: Gerald Charnoff, Esquire Shaw, Pittman, Potts and Trowbridge i800 M Street, N.W.

Washi ngton, 0.. C.

20036 Sandra S. Gardebring Executive Director Minnesota Pollution Control Agency 1935 W. County Road B2 Roseville, Minnesota 55113 The Environmental Conservation Library Minneapolis Public Library 300 Nicollet Mall Minneapolis, Minnesota 55401 Mr. F. P. Tierney, Plant Manager Prairie Island Nuclear Generating Plant Northern States Power Company Route 2 Welch, Minnesota 55089 Joclyn F. Olson, Esquire Special Assistant Attorney General Minnesota Pollution Control Agency 1935 W. County Road B2 Roseville, Minnesota 55113 Robert L. Nybo, Jr., Chairman Minnesota-Wisconsin Boundary Area Commi ssion 619 Second Street Hudson, Wisconsin 54016 Clarence D. Fierabend U. S. Nuclear Regulat; y Commission F. O. Box 374 Red Wing, Minnesota 55066 b 'I 2hg

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WASHING TON, D. C. 20555 o, % E "%... / JUN < 1979 Mr. Tom M. Anderson, Manager Nuclear Safety Departirant Westinghouse Electric Corporatien P. O. Box 355 Pittsburgh, Pennsylvania 1523D

SUBJECT:

REQUEST FOR ADDITIONAL INIORMATION REGARDING SMALL BREAK LOCA ANALYSIS As you are aware, the NRC staff is evaluating certain aspects of the NRC licer. sing process in light of the Three Mile Island Unit 2 (TMI-2) accident, of March 28, 1979. One of the aspects being addressed in this evaluation is the status of models used in safety analyses, especially those used to analyze transients and small break LOCA's. In order for the staff to complete its evaluation of the response of currently operating Westinghouse-designed plants to postulated small break LOCA's, additional information is reqJired. These information needs, which pertain to expected system behavior following postulated small break LOCA's and small break LOCA analysis methods and results, are identified in the enclosure to this letter. Please provide, within seven days of the date of receipt of this letter, your schedule for responding to the items contained in the enclosure. We recognize that some of the requested information may have already been provided to the staff in the course of otner reviews. In lieu of refer-encing already submitted material, we would prefer, in order to facilitate our review, that the responses be provided in one complete document. The information contained in the enclosure was discussed with your repre-sentatives at our May 31,1979 meeting. If you have any question regarding the contents of this letter, please contact P. D. O'Reilly, the assigned project manager. Sincerely, L jDUPLICATE DOCUMENT .).iEntire docu:aent previously entered into system under: t ANO_

Enclosure:

O No. of pages: 7 As stated Og j 6 f'. Lu.. ,~ "w M* ' a ~ :: ~ ~. ....u~ &T, C...,, a.a ,O}}