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Nuclear Power Plants

Nuclear power plants, like many sorts of industrial facilities, involve the use of hazardous materials. But unlike other facilities, the nation’s 103 nuclear power plants are required to have detailed emergency plans to protect the public in the event of an accident that could result in the release of radioactivity. Emergency plans for nuclear power plants are regulated by the Nuclear Regulatory Commission and the Federal Emergency Management Agency, which supervise graded exercises of those plans. The Bureau of Emergency Management is responsible for maintaining New Hampshire’s nuclear plant emergency plans. Those plans are reviewed and updated annually.

New Hampshire has one nuclear power plant, Seabrook Station in Seabrook, located within its borders and another plant, Vermont Yankee, located nearby in Vernon, Vermont. Both plants have 10-mile Emergency Planning Zones around them where emergency planning is concentrated.

The Seabrook Emergency Planning Zone (EPZ) includes 17 New Hampshire towns, all in Rockingham County: Brentwood, East Kingston, Exeter, Greenland, Hampton, Hampton Falls, Kensington, Kingston, New Castle, Newfields, Newton, North Hampton, Portsmouth and Rye. There are also six Massachusetts towns in the Seabrook EPZ.

The Vermont Yankee EPZ includes five New Hampshire towns, all in Cheshire County: Chesterfield, Hinsdale, Richmond, the Westport Section of Swanzey and Winchester. There are also seven Massachusetts and five Vermont towns in the Vermont Yankee EPZ.

Emergencies at nuclear power plants are classified at four levels (from least serious to most serious): unusual event, alert, site area emergency and general emergency.

  • Unusual events are in process or have occurred which indicate a potential degradation of the level of the safety of the plant. No releases of radioactive material requiring offsite response or monitoring are expected unless further degradation of safety systems occurs.
  • An alert indicates that events are in process or have occurred which involve an actual or potential substantial degradation of the level of safety of the plant. Any releases are expected to be limited to small fractions of the Environmental Protection Agency Protective Action Guideline exposure levels.
  • During a site area emergency events are in process or have occurred which involve actual or likely major failures of plant functions needed for protection of the public. Any releases are not expected to exceed EPA Protective Action Guideline exposure levels except near the plant site boundary.
  • In a general emergency events are in process or have occurred which involve actual or imminent substantial reactor core degradation or melting with potential for loss of containment integrity. Releases can be reasonable expected to exceed EPA Protective Guideline exposure levels offsite for more than the immediate plant site area.

For details on New Hampshire's emergency plans for Seabrook Station and Vermont Yankee, please refer to the following:

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