Severe Accidents in Sodium-Cooled Fast Reactors: Computational Fluid Dynamics Sensitivity Studies on the Thermal Ablation of Core Catcher

The present work aims at testing the computational fluid dynamics capabilities to simulate erosion of materials which interact with a corium mass. The main foreseen application is the design of external/internal core catchers or in-vessel retentions devices used to mitigate severe accidents for sodium-cooled fast reactors. 2D axisymmetric simulations of a corium jet impinging a sacrificial solid material show evidence of a pool-effect, previously observed in experiments, which contributes to limit the ablation process. Complementary sensitivity calculations assess the influence of jet diameter, temperature, and velocity.