United States Nuclear Regulatory Commission - Protecting People and the Environment
Home > NRC Library > Basic References > Glossary > Emergency classifications

Emergency classifications

Sets of plant conditions that indicate various levels of risk to the public and which might require response by an offsite emergency response organization to protect citizens near the site.

Both nuclear power plants and research and test reactors use the following emergency classifications:

  • Notification of Unusual Event—Events that indicate potential degradation in the level of safety of the plant are in progress or have occurred. No release of radioactive material requiring offsite response or monitoring is expected unless further degradation occurs.
  • Alert—Events that involve an actual or potential substantial degradation in the level of plant safety are in progress or have occurred. Any releases of radioactive material are expected to be limited to a small fraction of the limits set forth by the EPA.
  • Site Area Emergency—Events that may result in actual or likely major failures of plant functions needed to protect the public are in progress or have occurred. Any releases of radioactive material are not expected to exceed the limits set forth by the EPA except near the site boundary.
  • General Emergency—Events that involve actual or imminent substantial core damage or melting of reactor fuel with the potential for loss of containment integrity are in progress or have occurred. Radioactive releases can be expected to exceed the limits set forth by the EPA for more than the immediate site area.

Nuclear materials and fuel cycle facility licensees use the following emergency classifications:

  • Alert—Events that could lead to a release of radioactive materials are in progress or have occurred. The release is not expected to but the release is not expected to require a response by an offsite response organization to protect citizens near the site.
  • Site Area Emergency—Events that could lead to a significant release of radioactive materials are in progress or have occurred. The release could require a response by offsite response organizations to protect citizens near the site.

For further explanation, see Emergency Classification and Backgrounder on Emergency Preparedness at Nuclear Power Plants.

Page Last Reviewed/Updated Tuesday, October 28, 2014