United States Nuclear Regulatory Commission - Protecting People and the Environment
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Mitigation Strategies

Mitigation Strategies Order

Mitigating Strategies LogoAt Fukushima, flooding from the tsunami disabled internal electrical power systems after the earthquake had cut off external power sources, leaving the plants with only a few hours' worth of battery power.  Nuclear power plants need electrical power 24 hours per day, even when the nuclear reactors are shut down, to run equipment that cools the reactor core and spent nuclear fuel. The NRC issued a Mitigation Strategies Order on March 12, 2012, requiring all U.S. nuclear power plants to implement strategies that will allow them to cope without their permanent electrical power sources for an indefinite amount of time These strategies must keep the reactor core and spent fuel cool, as well as protect the thick concrete containment buildings that surround each reactor.  The mitigation strategies are expected to use a combination of currently installed equipment (e.g., steam-powered pumps), additional portable equipment that is stored on-site, and equipment that can be flown in or trucked in from support centers.

Related Documents:

For plant-specific documents, visit our Plant Implementation Status page.

Station Blackout Mitigation Strategies (SBOMS) rulemaking

At Fukushima, the earthquake and tsunami disabled both external and internal electrical power systems, leaving the plants with only a few hours' worth of battery power.  Since nuclear power plants need electrical power to keep their reactor cores and spent fuel pools cool, this loss of internal and external power—known as a station blackout (SBO)—was a significant challenge to workers at Fukushima.  The NRC's Station Blackout Mitigation Strategies rulemaking effort will permanently write into the agency's rules the requirements already imposed by the Mitigation Strategies Order that was issued by the NRC on March 12, 2012.  The eventual rule will ensure that if a plant loses power, it will have sufficient procedures, strategies, and equipment to cope with the loss of power for an indefinite amount of time.

Related Documents:

Learn more about the NRC’s rulemaking process.

Page Last Reviewed/Updated Wednesday, June 26, 2013