ML19309A702

Interim Deficiency Rept Re out-of-tolerance Threads for NSSS Support Anchor Bolt Nuts.Analytical & Empirical Test Data Will Be Correlated to Establish More Precise Methods for Determining Strength of Threads on Nut

ML19309A702
Person / Time
Site:	Wolf Creek
Issue date:	03/05/1980
From:	Koester G KANSAS GAS & ELECTRIC CO.
To:
References
NUDOCS 8004010034
Download: ML19309A702 (2)

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• KANSAS GAS AND ELECTRIC COMPANY

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G LEN N L. nOCSTEm vict patssogni.oetaceous March 5, 1980 Mr. W.C. Seidle, Chief Reactor Construction and Engineering Support branch U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 Re: STN 50-482 Subj: Interim Status Report - NSSS Lateral Support Anchor Nuts

Dear Mr. Seidle:

The purpose of this letter is to supplement our previous notification of December 27, 1979, to you concerning difficulties experienced at the Wolf Creek Site with out-of-tolerance threads for the NSSS lateral support anchor bolt nuts. In that notification you were advised that additional inspections and analyses of selected anchor bolt nuts would be initiated in order to ful.lv determine the extent and scope of these difficulties and, further, to assess the safety significance of .his matter pursuant to 10CFR50.55(e) regulations. A follow up report by March 1, 1980 was indicated at t*:' time.

Follow-up studies have since been initiated involving representative samples of nonconforming nuts identified at the two SNUPPS jobsites.

To date over 900 1/2 inch diameter nuts have been inspected and pertinent out-of-tolerance conditions identified for further analyses.

Three such nuts, representing worst case conditions identified between the two jobsites, have been tested at Lehigh University in accordance with test procedures approved by Bechtel Power Corporation. The results of these tests are currently being analyzed and will be compared with maxi-mum bolt loads being calculated for a given support structure. Based upon these analyses, efforts will also be made to correlate analytical and empirical test data in order to more precisely establish methods for determining the strength of the threads on the nut. This effort is expected to be complete on or about June 1, 1980. Until this effort is complete, we are unable to conclude whether the described difficulties represent a Significant Deficiency as defined in 10CFR50.55(e) .

! Upon completion of the studies indicated above, you will be advised of additional follow-up actions required, as well as our conclusions regarding 8004010 201 N Market - Wochsta. Kansas - Mail Accress: P.O. Box 208 l Wichsta. Kansas QQ

- Telephone: Area Code (316)2614451

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Mr. W.C. Seidle March 5, 1980

-the safety significance and reportability of this matter. In the event this item cannot be satisfactorily resolved by June 1st, an additional interim status report will be prepared and forwarded to you.

Very truly yours, j w, , = >) ge n0 J Gl'enn L. Koester Vice President - Operations GLK:bb

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