The EPR overall approach for severe accident mitigation

摘要

The EPR design includes provisions to cope with severe accidents including core melt situations: 1. Situations that would lead to large early releases such as containment bypass, high reactivity accidents, high-pressure core melt or global hydrogen detonation have to be prevented. 2. All other situations, including low pressure core melt have to be mitigated in such a way that the corresponding radiological consequences would necessitate only very limited protective countermeasures in a relatively small area and for a limited time for the population living in the neighborhood of the power plant. This means that there would be no need for permanent relocation, no need for evacuation outside the immediate vicinity of the plant, limited sheltering and no long-term restrictions in food consumption. To reach this objective, which is one of the Safety Authority's requirements, the EPR relies on a very robust containment and on various design measures intended to withstand extreme loads caused by a large range of internal events and external hazards. The deterministic method is used for the EPR safety demonstration, supplemented by probabilistic methods and appropriate R&D work. This paper outlines the major mitigating design features, summarizes the results of the Level 2 PSA and gives the main results of the evaluation of the radiological consequences of core melt on the environment.