ML19224C540
| ML19224C540 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 05/24/1979 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | Aldrich H MAINE BAG CO. |
| Shared Package | |
| ML19224C541 | List: |
| References | |
| NUDOCS 7907020504 | |
| Download: ML19224C540 (3) | |
Text
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4 UNITED STATES
. {h [] j NUCLEAR REGULATORY COMMISSION
,.g-WAS! *tNGTON, D. C. 20555 e,f M [p!
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J M9 Mr. H. N. Aldrich Maine Bag Company P.O. Box 550 Caribou, ME 04736
Dear Mr. Aldrich:
This is in response to your letter regarding the erciars by the Nuclear i
Regulatory Commission on March 23, 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.
t 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 overstressing of piping and supports for earthquakcs wMch eculd reasonably be expected to occur during the lifetimes of thest piants.
The eastern United States is generally believed to be a region of lcw seismicity, when compared to the western part of the country, but is not without significant historical seismic activity.
Attached is a map showing the location and intensity of earthquakes that hate occurred in your region.
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 p eventing 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, b
Ck.,
Harold R. Denton, Director Office of Nuclear Reactor Regulation
Enclosures:
Earthquake Maps for Southern Maine and Northern New England 700702 0 56 t/
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