Analysis of three-dimensional fluid field in the cavity for high pressure melt ejection(HPME)

This paper presents a study of three-dimensional fluid flow in the cavity for High Pressure Melt Ejection(HPME) scenario of severe accidents. This study was conducted to get a firm understanding of gas flow pattern inside the cavity based on cavity geometry before entering into the study of debris particle entrainment and trapping in the gas flow, which is usually associated with the interface heat transfer between the particles and gas flow. Using a simplified cavity geometry of Yonggwang units 3 and 4, several parameters such as inlet velocity, inlet/outlet sizes, capture volumes, horizontal/vertical heights, and maintenance gate were investigated, which appear to influence debris release mechanism to the containment atmosphere. The result shows non-uniform velocity profile at the cross-section (usually ratio of five to seven between the maximum and minimum velocities). Having a deeper capture volume showed strong recirculation inside the capture volume, which might help debris accumulation. These results will be used to implement the cavity design for future reactor types. Continuous study including heat transfer and particle transport will be conducted as part of this research in the near future