ML19289C846
| ML19289C846 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 01/15/1979 |
| From: | Stello V Office of Nuclear Reactor Regulation |
| To: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| TASK-03-06, TASK-3-6, TASK-RR NUDOCS 7901250297 | |
| Download: ML19289C846 (3) | |
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WASHINGTON, D. C. 20555 j
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g January 15, 1979 Docket No. 50-245 Northeast Nuclear Energy Company ATTN: Mr. W. G. Counsil, Vice President Nuclear Engineering and Operations Post Office Box 270 Hartford, Connecticut 06101 RE: MILLSTONE 1 As part of the Systematic Evaluation Program (SEP) the NRC staff is conducting a search of your docket for pertinent infoniation related to the seismic design bases of your facility. We are comparing the available infomation with current seismic design criteria in an effort to assess safety margins in the areas of geologic and seismic input and structural capability of safety-related structures, systems and equipment to with-stand earthquake effects.
As you know, the major NRC regulations dealing with seismic design are 10 CFR Part 50, Appendix A (General Design Criterion 2) and 10 CFR Part 100, Appendix A.
We recognize that both of these regulations were issued subsequent to the design of your facility. However, one of the objectives of the SEP is to compare the original design basis with current criteria.
Currently, the infomation on the docket is not sufficiently complete to adequately address the potential hazard of earthquakes, nor to detemine whether backfitting of additional seismic resistance would provide sub-stantial additional protection required for safety.
At this time, based on the docketed infomation, we expect that our safety assessmcat of the design bases in your FSAR and other filings will be positive in tems of actual safety margins at your facility.
However, we encourage you to closely follow our review as it progresses and to initiate any effort that you may believe necessary to confim the actual seismic safety margins of your facility. As part of our assessment, it is expected that we will require significant additional seismic design infomation not on the docket to support our seismic safety assessment. As our review indicates the need for such infoma-tion, we will infom you.
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r Northeast Nuclear Energy Company January 15, 1979 We expect the major area of review to be our assessment of the significance of changes in seismic design techniques from those used for your facility and those used today. As part of the effort to satisfy this objective, we have conducted a preliminary evaluation which indicates that the major area of difference in seismic input from current criteria relates to the shape of the ground response spectra used.
In this regard, the NRC staff is evaluating various site specific response spectra methodologies which may demonstrate a more realistic approach in detemining seismic input than that used in current licensing reviews. We encourage you to closely follow the progress of our work and initiate any effort you may feel is necessary to better assess the seismic safety margins of your plant.
To provide maximum assurance that the scope of any planned evaluations is appropriate, we suggest that detailed working level meetings with the NRC staff for your facility prior to the Initiation of your efforts would be beneficial. Until our evaluation of site specific response spectra metho-dologies is complete, it is our intent to use current criteria design spectra (e.g., Regulatory Guide 1.60, suitably modified for inelastic be-havior) as a baseline for our initial evaluation of actual seismic safety margins.
The NRC staff will be contacting you rariodically over the next several months to obtain information pertinc.it to our seismic evaluation of your plant. We expect that significant interaction with your technical staff will be required.
Si lcerely, 1,
or h Division of Operating Reactors Office of Nuclear Reactor Regulation cc:
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' Nor'theast Nuclear Energy Company cc:
William H. Cuddy, Esquire Day, Berry & Howard Counselors at Law One Constitution Plaza Hartford, Connecticut 06103 Anthony Z. Roisman Natural Resources Defense Council 917 15th Street, N. W.
Washington, D. C.
20005 E.
Northeast Nuclear Energy Company ATTN: Superintendent Millstone Plant P. O. Box 128 Waterford, Connecticut 06385 Waterford Public Library Rope Ferry Road, Route 156 Waterford, Connecticut 06385 Mr. James R. Himmelwright Post Office Box 270 Hartford, Connecticut 06101 Nuclear Regulatory Commission, Region I Office of Inspection and Enforcement ATTN: John T. Shediosky 631 Park Avenue King of F'ussia, Pennsylvanis 19406 o
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