The SCONE Software for Corium-Sodium Interaction

For the conception of the ASTRID fast neutron sodium-cooled reactor by CEA and its partners, severe accidents have to be taken into account. We focus here on a particular phenomenon that could occur during a severe accident sequence: the Fuel Coolant Interaction (FCI) or vapor explosion. A FCI would take place if corium (mixture of hot (similar to 3000 degrees C) molten core materials) came into contact with the more volatile liquid sodium which would lead to heavy corium fragmentation and to a pressure wave that could threaten the reactor structures, depending on the physical conditions. In the aim of precisely assessing the consequences of FCIs in the ASTRID reactor, CEA has started the development of the SCONE1 mechanistic computer code. In this paper, we briefly recall the physics that will have to be represented, describe the object-oriented architecture that was designed for our needs, explain our first numerical choices for SCONE before showing first results of the architecture capabilities.