ML093430127
| ML093430127 | |
| Person / Time | |
|---|---|
| Site: | Indian Point, Zion  |
| Issue date: | 06/05/1980 |
| From: | William Cahill, Early P Consolidated Edison Co of New York, Power Authority of the State of New York |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8006170451 | |
| Download: ML093430127 (2) | |
Text
CONSOLIDATED EDISON COMPANY of NEW YORK, INC.
4 IRVING PLACE, NEW YORK, N. Y., 10003 POWER AUTHORITY of the STATE of NEW YORK 10 COLUMBUS CIRCLE, NEW YORK, N. Y., 10019 June 5, 1980 Re:
Indian Point Unit No. 2 Docket No. 50-247 Indian Point Unit No. 3 Docket No. 50-286 Mr. Harold R. Denton, Director office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555
SUBJECT:
Report on Zion/Indian Point Near Site Study
Dear Mr. Denton:
The attached report entitled "Mitigation of Severe Accident Study Report Zicn and Indian Point Nuclear Units" and prepared by Westinghouse Electric Corporation covers the work performed on behalf of Consolidated Edison, the Power Authority of the State of New York, and Commonwealth Edison Company during the 60 day pericd of the subject study.
The report includes the presentations made to the NRC and ACRS on February 20 and March 5, 1980 respectively, and a brief status description.
The document reports the results of a series of state-of the-art analyses conducted within the 60 day time frame. It also includes, in some areas, conservative analyses based on existing MARCH work and is not Indian Point site specific.
This report is preliminary in nature and does not necessarily represent "firm" technical positions unless such positions are explicitly stated and identified as such in the document. Even where such "firm" technical positions are taken, we acknowledge that they may be subject to revision as a result of our on-going technical work and the information obtained from our joint technology meetings.
For example, p(A), the large pipe break probability_ 10-4), is more conservative than that chosen by the NRC (10
) in their April 9, 1980 letter regarding unresolved safety issues (see A-2). In addition, costs reported for the filtered vent containment system are very preliminary in nature* and should not even be considered as order of magnitude estimates of instale costs.
It is noted that our containment ultimate capacity evaluations fL?
are scheduled for completion in July 1980. A purely judgmental value was employed in the 60 day report, and our current assessment is that this is a conservative value. In support of this conservatism, Sections 4 and 8 clearly show that the steam explosion is not a credible event.
Also, the treatment of hydrogen in the 60 day 8oo617045r, I-re Is report may require substantial refinement for similar reasons.
these factors, coupled with other uncertainties, mean that the conclusions in the containment transient analysis area (Section 5) should be considered as preliminary, even though they represent our current best assessment of the plant response to these events.
Finally, we previously submitted on May 23,. 1980 an edited version of Section 3 covering residual risk assessment.
Section 3 is also being supplemented in our on-going work by a more detailed and comprehensive probabilistic risk assessment.
While we do not expect substantial differences in sequence ordering, we will employ this more detailed work to analyze both preventative and mitigative features.
We trust that, with these qualifications, this report will be a useful tool for your review efforts in this area.
We have attempted to present a balanced, comprehensive analysis given the permitted time frame.
Very truly yours, Paul J. Early William J. Cahill, Jr.
Vice President and Vice President Assist. Chief Engineer Consolidated Edison Co.
(Projects) of New York, Inc.
Power Authority of the State of New York Attachment cc:
Mr. J. Olshinski U. S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20014 Dr. J. Meyer U. S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20014 Mr., T. Rebelowksi, Resident Inspector U. S.. Nuclear Regulatory Commission P. 0. Box 38 Buchanan, New York 10511