Safety Valve and Helium Recovery System for JT-60SA Superconducting Coils

JT-60SA is a fusion experimental device using superconducting coils and a joint international research and development project involving Japan and Europe. It is to be built in Naka, Japan using infrastructure of the existing JT-60 Upgrade experiment. The missions of the design of JT-60SA safety valve and helium recovery system are to ensure safety for the excess pressure in the superconducting coil system, and to fully recover a large amount of helium gas to storage vessels during the normal transition (quench) or the fast discharge of the coils. In this paper, we designed the JT-60SA safety valve system. Installed places of pressure relief valves, flow diagrams, a concept with a selection of valve type, the detailed design and the operation scheme, and manufacturing of safety valve units are reported.