ML20009G905

Advises That Util 810309 Response to Evaluation of SEP Topic III-2.A Re Severe Weather Phenomena Does Not Provide Sufficient Justification to Modify NRC Values Re Design Wind Speed & Tornado Loadings

ML20009G905
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	08/03/1981
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:	Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
References
TASK-02-02.A, TASK-2-2.A, TASK-RR LSO5-81-08-004, LSO5-81-8-4, NUDOCS 8108050215
Download: ML20009G905 (4)

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Mr. David P. Hoffman 24 AUG 0 5 IW

.0 fluclear Licensing Administrator u p wumas Con ' rs Power Company WM

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212 West Michigan Avenue

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Jackson, Michigan 49201

SUBJECT:

BIG ROCK POIrlT - SEP TOPIC II-2.A, SEVERE WEATHER PHEf40MEf1A By letter cated December 17, 1980, we forwarded to you our evaluation of SEP Topic II-2.A, " Severe Weather Phenomena" for the Big Rock Point site.

Your response of March 9,1981, indicated that the staff values for extreme temperature, lightning strike frequency and ice and snow loading were appropriate.

However, you indicated that the staff values for design wind speed and tornado loadings are too high.

The extreme straight line wind speed of 80 mph selected by the staff represents an approximate 100 year wind as determined at both Grand l

Ranids and Sault Ste Marie, Michigan and reported in f4BS Building Science l

Series 118, " Extreme Wind Speeds at 129 Stations in the Contiguous United States." Your response suggests that a 62 mph wind sneed would be more appropriate in spite of observations of 67 mph at both the aforementioned n;ca ti on s.

In either case, the 62 mph wind would be expected to occur more frequently than every 20 years.

Viewed in this perspective the 80 mph wind provides a conservative basis for structural response evaluation.

The tornado wind speed chosen by the staff, 360 mph, is based upon the results ofastudybyJ.McDonaldofTexasTech. University (Enclosure 2ofphe December 17, 1980 letter) and represents an upper 95 percentile, 10-probability per year tornado.

In ficDonald's analysis, an expected 10-7 tornado wind speed of 272 mph which in higher thart the 250 mph suggested by CPCo, was identified, as appropriate.

The statistical analysis by Mcdonald utilizes weighting factors for population density, terrain features and tornado intensity based on the Fujita classification scheme which provides some degree of allowance for uncertainty in tornado observation.

The additional conservatism provided by use of the upper 95 percentile at the 10-7 proba-bility level assures that the 260 mph wind speed has a low likelihood of being exceeded.

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Based on the above, we feel that you have not provided sufficient justiff-cation for us to revise our evaluation. Therefore, we conclude that the evaluation sent to you on December 17, 1980 is correct and topic II-2.A is complete. The evaluation will be a basic innut to the integrated safety assessment for your facility.

The assessment may be revised in the future if your facility design is changed or if the NRC criteria relating to the subject is modified before the integrated assessment is completed.

Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing cc: See next page ADg[

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7/17/81 7/J 81 7/.y/81 7/V /81 7g/81 7/g/81 Nucresu m nesois~cu 24e OFFICIAL RECORD COPY

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o Mr. David P. Hoffman U. S. Favironmental Protecticn '

cc Mr. Paul A. Perry, Secretary.

Censumers Pcwer Coreany Agency Feceral Activities Branch 212 West Michigan Avenue Jackson, Michigan 49201 Region V Office ATTN: EIS COORDINATOR 230 South Dearborn Street Judd L. Bacon, Esquire Consumers Pcwer Company Chicago, Illinois 60604 212 West Michigan Avenue Jackson, Micnigan 49201 Hertert Grcssman, Esq., Chi ran Atcmic Safety and Licensing Joard U. S. Nuclear Regulatory Conmission Joseph Gallo, Esquire Isnam, Lincoln & Beale Washington, D. C.

20555 1120 Connecticut Avenue Dr. Oscar H. Paris Rcom 325 Atomic Safety and Licensing Board Washington, D. C.

20036 U. S. Nuclear Regulatory Commission Peter W. Steketee, Esquire Washington, D. C.

20555 505 Pecples Building Grand Rapids, Michigan 49503 Mr. Crederick J. Shen Atomic Safety and Licensing Board Alan S. Rosenthal, Esq., Chairman U. S. Nuclear Regulatory Commissicn Atomic Safety & Licensing Appeal Board Washington, D. C.

20555 i

U. S. Nuclear Regulatory Cocmission Big Rock Point Nuclear Pcwer Plant Wasningten," D. C.

205f5 ATTN:

Mr. C. J. Hartman Plant Superintendent Mr. J onn O' Neill, II Charlevoix, Micnigan 49720 R:ute 2, Box 44

aple City, Michi;an 49664 Chri sta-Mari a Rcute 2, Box 1CSC

^harlevoix Puclic Library Charlevoix, Michigan 49720 107 Clinton Street Charlevoix, Micnigan William J. Scanien, Esquire 2034 ?auline Boulevard Chai rman Ann Ar cr, Michigan 18103 County Scarc Of Supervisors Charlevcix Ccunty Charlevoix, Michigan 49720 Resident Inspector Big Rock Point Plant Office of the Governor (2) c/o U.S. NRC RR 13, Box 500 Room 1 - Capitol Building Lansing, Michigan 48913 Charlevoix, Michigan 49720 Mr. Jim E. Mills Herbert Semmel Ccuncil for Christa Maria, et al.

Reute 2, Box 108C Charlevoix, Michigan 49720 Ur:an Law Institute Anticch School of Law Thomas S. Moore 263316th Street, NW Atomic Safety & Licensing Apceal Board Washington, D. C.

204c0 U. 5. Nuclear Reculatory Ccamission Washington, D. C.

205

Mr. Dayid P. Hoffnan cc Dr. John H. Buck.

Atomic Safety end Licensing Appeal Board U. S. tiuclear Regulatory Corxaission Washington, D. C.

20555 Ms. JoAnn Bier 204 Clinton Street Charlevoix, Michigan 49720 e