ML20090L641

Submits Suppl to Util 751110 ATWS Ltr.Results of Studies, Proposed Course of Action & Schedule for Implementation Will Be Available by 760630

ML20090L641
Person / Time
Site:	Monticello
Issue date:	12/23/1975
From:	Mayer L NORTHERN STATES POWER CO.
To:	Ziemann D Office of Nuclear Reactor Regulation
References
14375, NUDOCS 9102120477
Download: ML20090L641 (2)

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/ NSE3 NORTHERN STATES POWER COMPANY MIN N E A POLL e. M O N N E SOTA 58400 s . - ~ . $f' lr December 23 , 1975 '

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Mr. D. L. Ziemann, Chief .

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Operating Reactors Branch #2 Division of Reactor Licensing

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Dear Mr. Ziemann:

MONTICELLO NUCLEAR GENERATING PIANT Docket No. 50-263 License No. DPR-22 Supplement to November 10 1975 A1VS 1.e t te r Your August 21, 1975 letter stated that design modifications should be implemented at Monticello to reduce the probability or consequences of an Anticipated Transient Without Scram (ATWS) event. In our Nov-ember 10, 1975 response, we agreed to provide additional information as it became availabic.

Work is presently underway in two areas on the ATWS issue. The prob-ability of an ATWS event having serious consequences is being evaluated l for plants similar to Monticello. The consequences of an ATWS event, l with various alternative modifications to mitigate the consequences, are being studied. We expect to have the results of these studies, our proposed course of action, and a schedule for implementation available by June 30, 1976. We believe this schedule is in agreement with the staff position on Monticello which states, ". . .the probability of oc-currence of an ATWS event with serious consequences is low enough to satisfy our safety objective today and for the next few years." (Docket No. 50-263, " Supplemental Testimony of Nuclear Regulatory Commission Staf f on Contention 11-33," February 28, 1975, page 93.)

Yours very truly, M" o.

L. O. Mayer, PE Manager, Nuclear Support Services L@t/MHV/ deb 1437b-cc: J. G. Keppler G. Charnoff MPCA Attn: J. W. Ferman m

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