The Development of Material and Fabrication Technologies for ITER Magnet Supports

The research and development of manufacture-related technology for ITER magnet supports is one of the tasks for construction. AISI 316LN austenitic stainless steel has been developed and tested as the main raw material. The material shows excellent mechanical properties at room temperature, 77 K, and 4.2 K. An alternative design for the toroidal field support manufacture without welding was carried out. The structural analysis shows no stress concentration and buckling in the present design during ITER operation. However, further engineering tests of the structural stability under various load combinations are also scheduled. A brazed connection to attach the cooling pipes to the support plates is suggested. Several kinds of candidate brazing fillers, such as Sn-Pb-, Ag-, and Cu-based alloys have been developed. The tensile strength of the brazed solders is up to 400 MPa at 77 K for the Ag-based and Cu-based fillers. For correction coil support, the plasma spray insulation coating was developed and introduced.