Progress of Manufacturing Trials for the ITER Toroidal Field Coil Structures

Japan Atomic Energy Agency (JAEA) has been conducting manufacturing feasibility trials of the toroidal field coil structures since 2009. Their feasibility was confirmed; however, since the structures were welded by using a one-side welding method, welding deformation was much larger than expected. By using a double-side welding method and optimizing the welding sequence, welding deformation can be minimized. Therefore, JAEA conducted full-scale trial manufacturing of basic segments to optimize the double-side welding sequence. After optimization, welding deformation was reduced. As a result, the double-side welding method will be used to manufacture the toroidal field coil structures as a manufacturer's selection.