A scheme of escalating emergency classes, each declared when pre-set emergency action levels are met. US plants use Notification of Unusual Event, Alert, Site Area Emergency and General Emergency; international practice uses alert, facility emergency, site area emergency and general emergency. Each class fixes who is notified, which facilities staff up and whether protective actions for the public are recommended.
Two barriers potentially lost, classify Site Area Emergency and get the EOF staffed.
Classify on the emergency action level that is met, not on where the event might go next; drills grade both under- and over-classification.
Also heard as
- emergency classification level
- ECL
Related terms
Fission product barrier
One of the successive physical barriers that keep radioactive fission products away from people and the environment.
EPZ
Emergency planning zone: the area around a nuclear plant where protective actions are pre-planned.
Sheltering
A protective action in which people stay indoors with doors and windows shut to reduce dose from a passing plume.
Defence in depth
The safety strategy of stacking independent layers of protection so no single failure can lead to harm.