Abstract
In this study, we construct the GOTHIC model of Chin Shan Nuclear Power Plant and FCVS (Filtered Containment Venting System) designed by IMI/Sulzer with GOTHIC code. Under conservative assumptions, we investigate the three cases: the first case investigate how long does it take to lower volume fraction of air of FCVS to below 20%; the second case investigate whether the combination of the volume fraction of air and volume fraction of hydrogen can enter flammable or detonable region at the transient of opening; the third case investigate whether the air will flow into FCVS when venting under low pressure;. The consequence of this study shows that the volume fraction of air of FCVS will be lower than 20% in 60 seconds; the combination of volume fraction of air and volume fraction of hydrogen can enter flammable or detonable region at the transient of opening; air will not flow into the FCVS when venting with FCVS even under low pressure. To lower the risk of hydrogen explosion, we suggest that when using FCVS, it should equip with nitrogen vessel and preheater to make the FCVS inert and avoid steam condensation before venting with FCVS, and accumulation of static electric charge should be avoided during venting process at any place of the venting route.