Evaluation of dryout region in a heap-like debris bed formed in an APR1400 pre-flooded reactor cavity

•The coolability of debris bed formed in APR1400 pre-flooded reactor cavity is analyzed.•The shape of debris bed is assumed considering the geometry of APR1400 reactor cavity.•Multi-phase flows in heat-generating porous bed are calculated using CFD.•The ratio of dryout region of debris bed is calculated according to system pressure, effective diameter of particles, and repose angle of debris bed.