NRC Mitigation Strategies

Mitigation Strategies

Mitigation Strategies Order

At 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.
Process Overview
Mitigating Strategies: Safely Responding to Extreme Events (NUREG/BR-0523)

Related Documents:

• NRC Order on Mitigation Strategies (EA-12-049) (March 12, 2012)
• NRC-issued guidance for Mitigation Strategies Order (JLD-ISG-2012-01), Revision 1 (January 22, 2016)
• Industry-issued guidance for Mitigation Strategies Order (NEI 12-06), Revision 2 (Decmeber 2015)

For plant-specific documents, visit our Plant-Specific Japan Lessons-Learned Activities page.