Design of Thermal Shield for the ITER Cryostat

Publisher Summary 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(ITER). In ITER, superconducting coils, such as Toroidal Field (TF) coils and Poloidal field (PF) coils are used and the total weight is around 25,000 tones. 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/m2 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. The thermal shields are designed to meet the heat load and cooling condition requirements. Additionally, they are designed to be maintained using remote handling techniques.