Nuclear power plant emergencies are classified into one of four classifications described below. At each level, PG&E would notify local, state and federal officials. These officials would take action as outlined in their emergency plans.
Unusual Event A minor, unplanned event has taken place, or a security threat may have occurred. No risk to public health and safety.
Alert A plant safety system has been damaged or may have been damaged, or security event may have taken place that involves risk to site personnel or damage to site equipment.
A Site Area Emergency A radiological release may be expected to occur or has occurred, or a security event may have taken place that damaged plant equipment. The release would not be expected to exceed federal exposure limits beyond the plant site boundary, an area about 1,000 yards from the reactors.
A General Emergency A significant release of radioactivity has occurred or may occur, or a security event may have taken place that results in loss of physical control of the plant. Protective actions may be directed in several of the Protective Action Zones.