ITER cryostat thermal shield detailed design

摘要

The structural design and study on fabrication and assembly of the cryostat thermal shield for International Thermonuclear Experimental Reactor (ITER) has been conducted. The cryostat thermal shield is attached to cover the cryostat inner wall in order to reduce the radiation heat loads applied to the superconducting coils operation at 4 K. The thermal shield consists of low- emissivity foils which are passively cooled and shield plates which are actively cooled with low temperature helium gas. The foils are multi-layered assemblies and are attached on both surfaces of the shield plates. The material of the foils are silver coated 304 stainless steel, polyimide or polyester. The silver coated stainless steel foils should be adopted to the foils at the locations where radiation dose is over 10 MGy. The route of coolant pipes for the shield plates is designed so as to keep the surface temperature of the shield plates below 100 K. This report describes the detailed design of the cryostat thermal shield, and outlines the fabrication and assembly procedures. (J.P.N.)