Emergencies at Nuclear Power Plants

Nuclear plants are designed to provide multiple barriers to prevent escape of radioactive material. The operation of these facilities is closely monitored and regulated by the Nuclear Regulatory Commission (NRC). Accidents at these plants are very unlikely, but possible. All nuclear plants work with local, state and federal officials to prepare emergency plans for the area within a ten mile radius of the plants. An outdoor emergency warning system is currently in place. It consists of sirens placed throughout the ten mile radius of each plant. The sirens are tested the first Wednesday of each month. Four categories have been established to describe the potential impact on the public and the severity of emergency conditions at the nuclear power plant.

Unusual Event
Events are in process or have occurred which indicate a potential degradation of 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 of the level of safety of the plant or a security event that involves probable 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 in process or have occurred which involve actual or likely major failures of 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) that prevent effective access to equipment needed for protection of the public. Any releases are not expected to result in exposure levels which exceed 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 results in 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.