Progress of ITER TF Coil Development in Japan

The authors performed some trials on TF coil fabrication and started first TF coil fabrication. In the trial on radial plate (RP) fabrication, flatness of machined RP section satisfied the target flatness of 1 mm and laser welding technique for joining RP sections was developed. The RP manufacturing plan is revised based on these trial results and fitting method of heat-treated conductor, whose length changes by its heat treatment, is also decided in this plan. Fabrication of the RP materials for the first TF coil has been completed and they satisfied the requirements, such as yield strength of 900 MPa at 4K. Preparation and commissioning of the tooling are in progress.