CFD Simulations in Complex Nuclear Containment Configurations

Abstract

Two-phase flows with water droplets have a significant influence on the thermal-hydraulic behaviour within Pressurized Water Reactors PWR. Such flows take place in the form of spray cooling, inter alia, in French nuclear reactors. In the case of a leak in the primary circuit of a PWR, hot steam will be released in the containment, which results in a pressure and temperature increase. The spray system ensures the reduction of the containment pressure and may, thus, help to avoid nuclear incidents. This work presents firstly a CFD simulation of spray cooling as well as aerosol particle washout by means of a spray system in a real size nuclear containment. The parallel performance of the simulations within a two-room model containment called $THAI^+$ is also investigated. Due to the large size and geometric complexity of this configuration, numerical grids with high refinement levels have to be generated to get accurate simulation results. For this reason, a good scalable CFD code is indispensable in order to achieve accurate simulations in realistic computional times. Since another aim of this work is to define guidelines for the optimum use of computational resources, the scalability tests will be performed on four different grid styles with six mesh resolutions up to $39{-}40\times 10^6$ elements.