ESCADRE and ICARE code systems

The French severe accident code development program is following two parallel approaches. The first one is dealing with ''integral codes'' which are designed for giving immediate engineering answers. The second one uses a more mechanistic approach to produce the capability for detailed analysis of experiments, in order to get a better understanding of the scaling problem and produce better confidence in plant calculations. In the first approach a complete system has been developed and is being used for practical cases: this is the ESCADRE system. In the second approach, a set of codes dealing first with primary circuit is being developed: a mechanistic core degradation code, ICARE, has been issued and is being coupled with the advanced thermalhydraulic code CATHARE. Fission product codes have been also coupled to CATHARE. The ∫ ESCADRE system and the mechanistic ICARE and associated codes are described. Their main characteristics are reviewed and the status of their development and assessment given. Future studies are finally discussed. (Author)