Dust Removal Experiments for ITER Blanket Remote Handling System

Abstract

To reduce maintenance workers' dose rate caused by activated dust adhering to the ITER blanket remote handling system (BRHS), dust must be removed from BRHS surfaces. Dust that adheres to the top surface of the BRHS rail from cyclic loading of the vehicle manipulator is considered to be the most difficult dust to remove. Dust removal experiments were conducted to simulate the materials, conditions, and cyclic loading of actual BRHS operations. The tungsten powder used to simulate the dust was squashed, and the area of contact by cyclic load was increased, but the powder was not embedded into the matrix. The increase in the area of contact increased the total intermolecular force between a tungsten particle and the surface, which was considered the main force adhering dust to the test piece surface. A combination of dust removal methods, including vacuum cleaning and brushing, was applied to the simulated dust that adhered to the test pieces. The results showed that vacuum cleaning is effective in removing dust from the non-cyclic loaded surface. The combined methods were highly efficient in removing the dust that strongly adhered to the rail surface.