Key Issues
Nuclear Plants Designed and Constructed to Withstand Earthquakes
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July 2009
Key Facts
Designed for Maximum Projected Seismic Event
Every U.S. nuclear power plant is designed to withstand an earthquake equal to the plant’s maximum projected seismic event without any release of radioactive materials. U.S. reactors must be designed such that they can safely shut down during any earthquake within this range. Plant operators will shut down the reactor even if the seismic event is well within levels the design can accommodate. Operators then perform extensive inspections prior to restarting the plant.
If an earthquake exceeds the maximum level for which a plant is designed, it is not permitted to restart without U.S. Nuclear Regulatory Commission approval, following extensive inspections to determine if it has sustained any damage.
Each plant has seismic instrumentation to record earthquake-induced motions at the site. The recordings are used to evaluate the level of earthquake vibrations at the plant and determine if the plant is required to shut down.
Physical inspections supplement the recordings to evaluate the impact of an earthquake at the site and the condition of the plant structures, systems and equipment. In the event of an earthquake, employees will analyze the recordings and the inspection results before restarting the reactor.
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July 2009
Key Facts
- Nuclear power plant design and construction ensure the plants can withstand powerful earthquakes. Plant designs include a detailed evaluation of potential earthquake-induced ground motion at the site. This is followed by thorough analysis and testing of the plant structures, systems and equipment, using simulated earthquake-induced vibrations.
- If an earthquake above a specified level affects a plant, it must perform extensive inspections before a company can restart a reactor.
Designed for Maximum Projected Seismic Event
Every U.S. nuclear power plant is designed to withstand an earthquake equal to the plant’s maximum projected seismic event without any release of radioactive materials. U.S. reactors must be designed such that they can safely shut down during any earthquake within this range. Plant operators will shut down the reactor even if the seismic event is well within levels the design can accommodate. Operators then perform extensive inspections prior to restarting the plant.
If an earthquake exceeds the maximum level for which a plant is designed, it is not permitted to restart without U.S. Nuclear Regulatory Commission approval, following extensive inspections to determine if it has sustained any damage.
Each plant has seismic instrumentation to record earthquake-induced motions at the site. The recordings are used to evaluate the level of earthquake vibrations at the plant and determine if the plant is required to shut down.
Physical inspections supplement the recordings to evaluate the impact of an earthquake at the site and the condition of the plant structures, systems and equipment. In the event of an earthquake, employees will analyze the recordings and the inspection results before restarting the reactor.
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