During the emergency phase, the Crisis Cell defines the spheres of action and intervention. This is the area covering the territories in which emergency preventive or protective measures are put in place immediately following a nuclear accident. In an emergency, these spheres are proposed on the basis of radiological evaluation for the implementation of the following measures:
- the area in which shelter should be sought;
- the area in which potassium iodide tablets should be taken;
- the evacuation area;
- the area in which foodstuffs must be monitored and protected;
- the area for agricultural products and feed for livestock.
Its boundaries are not necessarily those of the primary planning zone, and can therefore exceed its limits.
Such a sphere is defined on the basis of the reference levels measured, taking into account the principles of proportionality and effectiveness. Each sphere can include one or several entire communes and/or one or several areas of one or several communes.
Such a sphere does not necessarily cover the entire primary planning zone and can exceed its limits.
While the planning zone defines the territories for which a protective measure is planned in advance, the action and intervention sphere includes the part of the territory where it is decided this measure should be implemented in an emergency.