Numerical Modeling of Condensation Pool (NUMPOOL)

The behaviour of a pressure suppression containment of a BWR is studied by performing CFD and Fluid-Structure Interaction (FSI) calculations. Experiments performed at the Lappeenranta University of Technology with the PPOOLEX facility are modelled. PPOOLEX is a scaled-down two-compartment model of a pressure suppression containment of a BWR. In the experiments, vapour is blown into the drywell compartment. When the pressure increases, the mixture of air and vapour flows through the vent pipe into the water pool of the wetwell compartment. Two-phase CFD simulation of an experiment has been performed by using the FLUENT code. Large, rapidly condensing steam bubbles may cause severe loads on the pool structures. The bubble collapse and the resulting pressure loads are first analyzed analytically and numerically by using simplified assumptions. The obtained pressure source is then used for preliminary analysis of the bubble collapse in a realistic BWR containment. Calculations of the BWR containment are performed by using an acoustic-structural FEM model with FSI coupling.