Analysis of Gas Behavior in Reactor Building by 3D Compressible Thermal Fluid Dynamics Simulation Code: BAROC for Safety Analysis Under Severe Accident Conditions

Abstract

We developed the CFD analysis code BAROC for the reactor containment vessel and reactor building in a situation of severe accident. BAROC can analyze the three-dimensional thermal-hydraulics of multi-component gas and FP (fission product) aerosol in detail. By applying the implicit method and partially parallel processing, high-speed calculation is possible even for large-scale systems. The physical model and numerical solution method used in BAROC, as well as the results of analysis of the leakage and diffusion behavior of hydrogen and FP in the reactor building at the time of the accident of the Fukushima Daiichi Nuclear Power Plant are introduced.