ML19289C842
| ML19289C842 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 01/15/1979 |
| From: | Stello V Office of Nuclear Reactor Regulation |
| To: | Reed C COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 7901250289 | |
| Download: ML19289C842 (3) | |
Text
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4 UNITED STATES i
NUCLEAR REGULATORY COMMISSION g
WASHINGTON, D. C. 20665 f
January 15, 1979 Docket No. 50-10 Commonwealth Edison Company ATTN: Mr. Cordell Reed Assistant Vice President Post Office Box 767 Chicago, Illinois 60690 Gentlemen:
RE: DRESDEN NUCLEAR POWER STATION UNIT NO.1 As part of the Systematic Evaluation Program (SEP) the NRC suff has completed a search of your docket for pertinent infomation related to the seismic design bases of ynur facility. We find that your docket lacks sufficient infomation concerning the seismic design input and structural capability for safety-related structures, systems and equip-ment to withstand earthquake effects to enable us to complete our evaluation.
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 y
resistance would provide substantial additional protection required for safety.
We recognize that your facility possesses inherent structural capabili-ties to withstand earthquake effects. However, there is insufficient infomation docketed to adequately quantify such capability. We believe that a significant effort on your part may be required to assess the seismic safety margins of your facility, This matter has been generally discussed with your representatives, as part of the SEP, to assure that the issue will be properly resolved within the time frame of the SEP.
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Commonwcalth Edison Company January 15, 1979 While the docket does not contain sufficient information on geologic and seismic input to allow a comparison to current criteria, seismic input information for your facility could be developed based on current criteria and a bounding conservative assessment; however, evaluation of various site specific response spectra methodologies may demonstrate a more realistic approach in determining seismic input. Staff effort in these methodologies is expected to lead to acceptable procedures for determining site specific spectra. We encourage you to closely follow the progress of our work aimed at the development of a seismic input for your facility.
Although we have undertaken this seismic input effort, we expect you to be responsible for a documented seismic design basis for your facility.
In addition to seismic input, this would include analytical or other pro-cedures fer demonstrating that acceptable structural design criteria are satisfied. The staff expects to work with you in this effort, especially in the areas of definition of acceptable seismic structural design criteria and seismic input.
If you wish to follow such an approach, as suggested by the staff, please inform us within 30 days. Additionally, please provide, within the next 90 days, a description outlining your program for documenting a seismic design basis and a program schedule. To provide maximum assurance that both the scope and schedule are acceptable, we suggest that detailed working meetings for your facility in the next 90 days would be beneficial.
- incerely,
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'Commo' wealth Edison Canpany January 15, 1979 n
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Mr. John W. Rowe Isham, Lincoln & Beale Counselors at Law One First National Plaza, 42nd Floor Chicago, Illinois 60603 Mr. B. B. Stephenson Plant Superintendent Dresden Nuclear Power Station
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Rural Route #1 Morris, Illinois 60450 Morris Public Library 604 Liberty Street Morris, Illir.ois 60451 U. S. Nuclear Regulatory Commission ATTN: Jimmy L. Barker Post Office Box 706 Morris, Illinois 60450 s
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