Visualization on Mobilization Behavior of Radioactivated Dust in a Vacuum Chamber

Abstract

Activated-dust mobilization in a vacuum vessel of a fusion reactor under the Loss-of-Vacuum Accident (LOVA) condition was observed to investigate its flow characteristics from a viewpoint of the fusion safety research. The simulated dust was set on a floor in a small vacuum chamber and its flow mobilization when the LOVA occurred was visualized using a slit-light source, CCD camera and VCRs, and a moving speed of the mobilized dust was measured by a laser velocimetry. Experimental parameters in the present study are the breach positions on the vacuum chamber, set-up positions of the dust and temperature. The dust was conveyed from the vacuum chamber to the outside by a natural convection flow under a heated wall condition, and it was not go to the outside under a RT condition. The dust distributions in the vacuum chamber after the LOVA were clarified under conditions of different breach positions.