ML19296D374

Responds to NRC 791017 Request for Util Input Re ATWS Issue. Util Concurs W/Basic NRC Objectives.Alternative II of NUREG- 0460 Meets All Mitigation Criteria for Hypothesized ATWS Situation for Util BWR-5 Reactor Sys

ML19296D374
Person / Time
Site:	Zimmer
Issue date:	02/27/1980
From:	Borgmann E CINCINNATI GAS & ELECTRIC CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NUDOCS 8003040453
Download: ML19296D374 (2)

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TIIE CINCINNATI GAS & ELECTRIC C O M PA N Y '~ ^~ ~ ' "5 CINCIN N ATI OHIO 4 52 01 EA BORGMANN

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Docket No. 50-358 February 27, 1980 Mr. Harold Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 RE: WM. H. ZIMMER NUCLEAR POWER STATION -

UNIT 1 (ZPS-1), THE CINCINNATI GAS &

ELECTRIC COMPANY'S POSITION ON ATWS

Dear Mr. Denton:

This is in response to your October 17, 1979 letter seeking utility input on the ATWS issue. While CG&E concurs with the basic Staff objectives, at the same time, we believe that all other considerations should not be totally disregarded.

Consistent with this philosophy, we have concluded that Alternative II as set forth in NUREG 0460 meets all mitigation criteria for a hypothesized ATWS situation for the Zimmer reactor system, a BWR-5. Our review of your Staff's approach to the mechanisms leading to postulated failure to scram results in the identification of only two such triggering events: failure of the initiating logic cr failure of the scram air header valves.

Both of these are mitigated by the use of Alternative II as here-tofore proposed. If your Staff has considered other initiating mechanisms, we would appreciate being apprised so that we can review the matter further. To repeat the commitment contained in our September 30, 1976 letter, upon receipt of your concurrence, we stand ready to begin implementation of Alternative II.

In response to the next to the last paragraph in your letter of October 17, 1979, no formal BWR ATWS owners group has been formed, but we have and will continue to participate in an ad hoc owners group. This group participated in the development and review of the General Electric Company December 1979 submittal regarding ATWS.

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To: Mr. Harld Denton, Director February 27, 1980 Re: Wm. H. Zimmer Nuclear Power Station - Page #2 Unit 1 (ZPS-1), The Cincinnati Gas &

Electric Company's Position on ATWS Let me reemphasize the Company's commitment to work with the Staff to come to a mutually acceptable resolution of this matter.

Very truly yours, THE CINCINNAT. S& ELECTRIC COMPANY By P "

E. A. BORGMANN Senior Vice President EAB: dew