R&D and Design Studies for the ASTRID Core-Catcher

The reinforcement of safety requirements for new sodium fast reactors leads to take into account whole core melting situations during the reactor design phase. In order to mitigate the consequences of a hypothetical core melting in ASTRID, a core-catcher will be implemented. Its main requirements are to fit the whole material core-inventory, to insure the sub-criticality and cooling of the corium during the accidental and post-accidental phases. Two options of core-catcher designs are studied: one implemented in the primary vessel ('in-vessel'), one located outside the primary vessel ('ex-vessel'). To support the core-catcher development, a large R&D program is underway regarding the molten core progression (characteristics of the corium arriving on the core-catcher), protective materials to limit the thermo-mechanical loads of the core-catcher, corium behavior and cooling on the core-catcher – all being supported by experimental programs. (author)