ML20126E921

Responds to 810126 Request Re E Tophan Concern About Siting of Facilities Near Minor Fault.Plant Designed to Withstand Earthquake Ground Motion Larger than Ever Recorded within 200 Miles of Site

ML20126E921
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	02/19/1981
From:	Dircks W NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
To:	Aspin L HOUSE OF REP.
Shared Package
ML20126E923	List: ML20126E921 ML20126E924
References
NUDOCS 8103040889
Download: ML20126E921 (2)

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.., N 'FEB 191981 Md j The Honorable Les Aspin

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' United States House .of Representatives- 1. ~ '/

Washington, D. C. 20515 .

/h/g - j y .% . j-j Cear. Congressman l Aspin: y

. Cu Ny Q /, 1 This letter is in-regards to your request ~dited January 26,.1981, 1 concern expressed by Mr. Elgin Tophan of renosha,. Wisconsin, on why? the. f Zion Station is located near a minor fault.< l-Geologic faul'ts are common everywhere. However in'the eastern and central f United States they are generally hundreds of million years old. . Faults of l that age in the central and eastern U. S. are not -considered to 'be~ .

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hazardous. Commonwealth Edison: investigated the. site and region and the results of its investigations were reviewed.by the U. S.' Geological Survey ,

(USGS), the U. S'. Coast and Geodetic Survey ,(USC&GS), and the AEC. The .;

results 'of these reviews led to the conclusion that there are no faults in ~

the site vicinity that would tend to localize earthquakes an:! therefore be considered hazardous. These conclusions were documented in the AEC Safety ,

Evaluation Reports.for thefZion Station dated 21 August 1958 and 6' October. {

1 971 . m In addition, the Zion plant has been designed to withstand earthquake ground notions.of 0.17 , which is equivalent 1to the occurrence of a Modified Mercalli j 7.ntensity (MMI)9VII-VIII near'the site. f o earthquake'that large has ever ,

been recorded within 200 miles of the site. MMI VII-VIII is equal to the largest historical earthquake that has been recorded in the' Central Stable [

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Region of f; orth America, a very broad area 16at extends from the Rocky lbuntain '

Front to the Appalachian Plateaus.

To assure ourselves that all'available infor, ation has been and ' continues to be reviewed so ths.t we may carry out our.res:cnsibility to protect the health i

and safety of the public, our r+.aff contacted Mr. Tophan in hooes of folloning '

up on any lead Mr. Tophan may have. had on t.ninvestigated faults.. While Mr. Tophan had no specific information and could not re:all any geologists that might l have the it. formation requD ed, it .dic' provide us the opportunity to indicate  ;

to Mr. Tophan that the liRC (forner AEC) does require that nuclear power plants  !

be designed assuming the ocr.urrence of the raximum historic earthquake at the <

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Tne 2C staff maintains frequent comunications with the states in the Zicn area and is usually aware of most published information concerning areas arc;nd  ;

nuclear power plants. Mr. Tophsn was not aware that the f3C staff had a :c e cf.stoff geologists and seismologists nor the fact that nuclear power pla ts >

i *. t a have to be designed for earthquakes as great at, the rsxinum historical.

Mr. Tophan has not raised any new information which the staff is not gercrally aware of, we see no need to pursue this subject further. We trust this i answers your request. Please let us know if there are any further questt.as. _

Sincerely,_

(mvA) T. A, Ntm Killiam.J.

Executive Dircks Director for Operations ,

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