NRC STAFF ISSUES BULLETIN TO NUCLEAR POWER PLANTS

ON STRATEGIES TO HANDLE EXTREME EVENTS

The Nuclear Regulatory Commission staff has issued a Bulletin to companies licensed to

operate U.S. nuclear power plants, requesting information on how the plants are complying with 

requirements to deal with the potential loss of large areas of the plant after extreme events.

The events at the Fukushima nuclear power plant in Japan, following the March 11

earthquake and tsunami, have highlighted the potential need for U.S. plants to implement 

mitigative strategies, sometimes called “B5b” strategies. The NRC seeks information on the 

plants’ approach to ensuring their strategies remain effective over time. The NRC continues to 

conclude these strategies can effectively cool down reactor cores and spent fuel pools even if a 

plant’s normal safety systems are damaged or unavailable.

“Our initial guidance on these strategies focused on the mitigative actions themselves, but 

we also need to consider things such as operator training and maintaining the related equipment,” 

said Eric Leeds, Director of the NRC’s Office of Nuclear Reactor Regulation. “These strategies 

and resources are an important part of the multi-layered approach the NRC requires so plants can 

maintain or restore their abilities for core cooling, containment integrity, and spent fuel pool 

cooling even if they lose large areas of the plant, for instance after an explosion or fire.”

“We’ll review the plants’ responses to see if they need to take any additional actions to 

meet our existing requirements, along with seeing what the NRC might need to do to enhance 

those requirements and continue to protect public health and safety,” said NRC Chairman 

Gregory B. Jaczko. “Our task force examining information from the Japan quake will also go 

over the Bulletin responses as part of its ongoing review of our requirements.” 

Plants have until June 10 to respond to the Bulletin with information confirming their 

mitigative-strategy equipment is in place and available, as well as that the strategies can be 

carried out with current plant staffing. Plants have until July 11 to respond to the Bulletin with

further information in areas including:

• how essential resources are maintained, tested and controlled to ensure 

availability;

• how strategies are re-evaluated if plant conditions or configurations change; and

• how arrangements are reached and maintained with local emergency response 

organizations.

NRC NEWS

U.S. NUCLEAR REGULATORY COMMISSION

Office of Public Affairs Telephone: 301/415-8200

Washington, D.C. 20555-0001

E-mail: opa.resource@nrc.gov Site: www.nrc.gov

Blog: http://public-blog.nrc-gateway.gov

No. 11-078 May 11, 2011
Plant management must guarantee under oath that all responses to the Bulletin are accurate and 

complete. 

Bulletin 2011-01, “Mitigating Strategies,” will be available on the NRC website and via 

the agency’s electronic document database, ADAMS, by entering “ML111250360” in the 

ADAMS search engine.

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