Thermal Hydraulic Analysis for CFVS Depending on Outlet Orifice Size

Containment Filtered Venting System (CFVS) is one action that can be used to protect the containment and the facility while mitigating radioactivity releases to the environment. The Containment Filtered Vented System (CFVS) is installed in nuclear power plant to protect the integrity of containment building against the over pressurization and to remove fission products which are in aerosol from the fuel into the containment during severe accidents. This study analysed the thermal hydraulic characteristic using the FLOWNEX about design criteria of under accident condition according to four different orifice size, such as 0.13, 0.15, 0.2 and 0.3m. The orifice size of 0.1 m and 0.3 m are satisfied for design criteria at the level of scrubbing water and depressurization, respectively. The optimum orifice size is 0.15 m because the operator can less open the isolation valves manually.