Design of Thermal Shield for the ITER Cryostat

摘要

Japan Atomic Energy Research Institute is studying a thermal shield in a cryostat, whose diameter is 36m and height is 34m, for International Thermonuclear Experimental Reactor. The thermal shield is cooled by 80-K helium gas. The designed radiation heat leak from room temperature to 4-K superconducting coil and the structure is less than 0.24 W/m~2 by using a multi-layer metal plate. Total heat load of thermal shield is 147 kw at 80K. The thermal shield is a segment structure in order to allow a maintenance and replacement by remote handling system.