フィルタベントシステム高効率化におけるベンチュリノズルの流動特性に関する基礎研究

抄録

Nuclear power plants are equipped with several facilities to prevent radioactive materials from leaking into the surrounding environment in the event of a severe accident such as a loss of total power supply (station blackout, SBO). One of them is venting to prevent the Primary Containment Vessel (PCV) from being damaged due to pressure increase inside the PCV. In the venting operation, hydrogen and water vapor (vent gas) inside the PCV are released outside the PCV to reduce the pressure inside the PCV and maintain the integrity of the PCV. The filtered containment venting system (FCVS) removes radioactive materials from the vent gas before releasing them to the environment during the venting process. On the other hand, in actually, when the filtered containment venting system is used, the flow rate of the vent gas varies with time after the start of venting because the vent gas is discharged into the environment from PCV. In addition, the removal efficiency of radioactive materials by the filtered containment venting system is greatly affected by the flow pattern of the venturi scrubber nozzle. However, previous studies have not clarified the change in flow pattern due to the change in vent gas flow rate. In this study, the vent gas flow rate into the venturi scrubber nozzle was varied, and the flow pattern inside and outside the nozzle was clarified.