The Development of a Multiphysics Coupled Solver for Studying the Effect of Dynamic Heterogeneous Configuration on Particulate Debris Bed Criticality and Cooling Characteristics

For a sodium-cooled fast reactor, the capability for stable cooling and avoiding re-criticality on debris bed is essential achieving in-vessel retention when severe accidents occur. However, an unexploited uncertainty still existed regarding compound effect of heterogeneous configuration dynamic particle redistribution bed’s criticality safety assessment. Therefore, this research aims to develop numerical tool investigating effects different transformations configurations criticality/cooling Based newly proposed methodology in research, via integrating Discrete Element Method (DEM) with Computational Fluid Dynamics (CFD) Monte-Carlo-based Neutronics (MCN), coupled CFD–DEM–MCN solver was constructed originally created interface integrate two existing codes. The configurations’ assessments were also quantitively confirmed, indicating that particle-centralized fissile material had dominant negative margin re-melting more evident impact than net bed-centralized effect. This can serve further assess multi-physics simulation approach, leading safer SFR design concepts.