Global thermodynamic approach of the molten core-concrete interaction (MCCI) and selected applications in the nuclear field

As part of a study on nuclear reactor safety, we modelled the thermodynamical properties of a complex mixture called 'corium' obtained in the unlikely event of a severe accident in a nuclear power plant, if the reactor core melts through the vessel and slumps into the concrete reactor cavity. When the core and the concrete interact, the phenomenon is called 'molten' Core-Concrete Interaction (MCCI). The equilibrium state of the corium is calculated by the GEMINI2 program linked to the database TDBCR, which includes the thermochemical properties of the main constituents of the different materials present in a pressurized water reactor. The methodology of assembling a self-consistent database and more selected applications are presented. Such an approach is essential to increase the knowledge base of the material 'corium' to feed other codes assigned to nuclear reactor safety. (authors)