Evaluation of debris transport in ECSS long term core cooling period using VOF method and particle tracking method

In the present study, the coolant flow in the containment pool and debris transportation are analyzed using Computational Fluid Dynamics (CFD). The flow field is calculated using Volume of Fluid (VOF) method and transport fraction of debris is evaluated using the Lagrangian particle tracking method. The particle dynamic equations are calculated after achieving a steady state of the flow field. A friction force between sediment debris and the containment floor is added to particle dynamic equations. The transport fraction calculated using the particle tracking method is compared to that calculated using the evaluation method in guidelines of PWR recirculation sump evaluation methodology (NEI 04-07). The evaluation method in NEI 04-07 shows more conservative with respect to the transport fraction than the particle tracking method. (authors)