THAI-HM2 Benchmark Study with STAR-CCM+ Code Simulation

The Filtered Containment Venting System (FCVS) has been emphasized that it should passively retain fission product releases to environment and control the hydrogen produced in a severe accident. It is possible to have combustion or explosion of hydrogen by a convection flow, a diffusion process, and a condensation or a change of vapor and hydrogen in the local and global region of containment. When a FCVS is operating, i.e., exhausting the containment atmosphere, it needs to check the gas components and hydrogen risk. THAI Project is an experiment about Thermal hydraulics, Hydrogen, Aerosols, and Iodine by OECD/NEA organization from 2010. THAI-HM2 benchmark studies are performed with STAR-CCM+ code, f℃using on the mesh structures, turbulent models, and gas models. Numerical errors by a mesh type was found quite important, and controlling turbulent model could ease off the erosion problem. Whether the equation of state is the ideal gas property or the real gas property (Redlich-Kwong model) did not make differences. With these insights, in the study about nuclear containment scaled cases, the polyhedral mesh is recommended because the heat transfer between solid structure and fluid flow region is significantly locurred. Also, such case could be that turbulent diffusion coefficient is larger than laminar diffusion coefficient, i.e., the turbulent Schmidt number could have a significant role. This work was supported by the Nuclear Safety Research Program through the Korea Foundation Of Nuclear Safety (KOFONS), granted financial resource from the Nuclear Safety and Security Commission (NSSC), Republic of Korea (No. 1305008- 0315-SB110).