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Nuclear Power Plant

Commercial nuclear power plants have long been one of, if not the most regulated aspect of US Critical Infrastructure. With 98 reactors within 60 nuclear power plants in operation in 30 states, nuclear power consistently generates approximately 20% of our nation’s electricity. Within the reactor core, uranium fuel pellets contained in rods produce a considerable amount of heat through a process called fission. This heat is converted into steam which powers a turbine to generate electricity for our homes.

The construction and operation of these facilities is closely monitored and regulated to prevent incidents. If the primary and secondary systems fail, emergencies are possible, including those with a radioactive release that could affect public health and safety. As a result, federal, state and local officials, in addition to these utilities are required to have comprehensive emergency plans in place to protect against and respond to incidents at these facilities. Through oversight provided by both the US Nuclear Regulatory Commission (NRC) and the Federal Emergency Management Agency (FEMA), these plans are reviewed, drilled and evaluated regularly to ensure they meet regulatory standards. It is the responsibility of The Division of Homeland Security and Emergency Management to maintain New Hampshire’s nuclear power plant off-site emergency plans, including annual reviews and updates.

To facilitate a preplanned strategy for issuing precautionary and protective actions during an emergency, there are two Emergency Planning Zones (EPZs) around a commercial nuclear power plant. The first, a Plume Exposure Pathway EPZ is a geographical area extending 10-miles beyond a nuclear power plant where it is possible people could be harmed by direct radiation exposure. The second, an Ingestion Exposure Pathway EPZ is a geographical area extending 50-miles beyond a nuclear power plant, where radioactive materials could contaminate water, food, and livestock.

As a way to group emergencies at these facilities and coordinate appropriate responses based upon actual effects and consequences, incidents at nuclear power plants are broken into Emergency Classification Levels (ECLs). From least severe to most severe, they are: Unusual Event, Alert, Site Area Emergency, and General Emergency.
  • Unusual Event: Events are in process or have occurred which indicate a potential degradation in the level of safety of the plant or indicate a security threat to facility protection has been initiated. No releases of radioactive material requiring offsite response or monitoring are expected unless further degradation of safety systems occurs.

  • Alert: Events are in process or have occurred which involve an actual or potential substantial degradation in the level of safety of the plant or a security event that involves probably life threatening risk to site personnel or damage to site equipment because of HOSTILE ACTION. Any releases are expected to be limited to small fractions of the EPA Protective Action Guideline exposure levels.

  • Site Area Emergency: Events are in process or have occurred that involve actual or likely major failures in plant functions needed for protection of the public or HOSTILE ACTION that results in intentional damage or malicious acts; (1) toward site personnel or equipment that could lead to the likely failure of or; (2) prevent effective access to, equipment needed for the protection of the public. Any releases are not expected to result in exposure levels which exceed the EPA Protective Action Guideline exposure levels beyond the site boundary.

  • General Emergency: Events are in process or have occurred which involve actual or imminent substantial core degradation or melting with potential for loss of containment integrity or HOSTILE ACTION that result in an actual loss of physical control of the facility. Releases can be reasonably expected to exceed EPA Protective Action Guideline exposure levels offsite for more than the immediate site area.

Seabrook Station:
The State of New Hampshire has one nuclear power plant within its borders, Seabrook Station in Seabrook, NH. This plant generates approximately 1,244 million watts of electricity per year, enough power to supply the annual needs of approximately 1.2 million families. There are seventeen (17) New Hampshire towns within the 10-mile EPZ around Seabrook Station: Brentwood, East Kingston, Exeter, Greenland, Hampton, Hampton Falls, Kensington, Kingston, New Castle, Newfields, Newton, North Hampton, Portsmouth, Rye, Seabrook, South Hampton and Stratham. There are also six Massachusetts towns in the Seabrook 10-mile EPZ.

For More Information:
Seabrook Station Emergency Prepareness Information




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