ML19269E922
| ML19269E922 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley, Surry, Maine Yankee, FitzPatrick  |
| Issue date: | 05/24/1979 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | Schmidt A AFFILIATION NOT ASSIGNED |
| References | |
| NUDOCS 7906290821 | |
| Download: ML19269E922 (1) | |
Text
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UNITED STATES
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MAY 3 41979 Mr. Allen Schmidt 7005 Bristol Blvd.
Edina, MN 55435
Dear Mr. Schmidt:
This is in response to your telephone call to the office of Vice President Mondale regarding the orders by the Nuclear Regulatory Commission on March 13, 1979, to shut down five nuclear power plants in the eastern United States because of questions about the ability of their piping systems to withstand earthquakes.
Shortly before those orders were issued, it became apparent to NRC staff that analysis techniques which had been used in the seismic design of safety-related piping for these five plants were not in accord with proven and generally accepted engineering practice.
The result could be over-stressing of piping and supports for earthquakes which could reasonably be expected to occur during the lifetimes of these plants. The eastern United States is generally believed to be a region of low seismcity, when compared to the western part of the country, but is not without signifi-cant historical seismic activity.
Some of the piping systems involved could, if failure occurred, cause loss of coolant to the nuclear reactor.
In addition, systems needed to shut the plant down safely in that event could also be affected. Thus, an earthquake of not extremely low likelihood would have the potential for causing an accident and for preventing operation of safety systems designed to cope with the accident.
Our objective is to review the situation in an expedited and disciplined manner so that these plants can be returned to operation with assurance that this will not constitute a threat to the public health and safety.
Sincerely, A
Harold R. Denton, Director Office of Nuclear Reactor Regulation 7906290g33 2142 2l4
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