Series production of the toroidal field (TF) coils for the ITER has been launched since Oct. 2013. In advance of manufacturing of the actual products, we have performed the preliminary tests and mock-up tests to clarify and confirm the conditions of the welding and machining processes. The ITER TF coil is a welded-structure to endure strong magnetic forces, and it is a huge component in the ITER machine with dimensions of 16.5m height and 9.0m width and a weight of more than 300 ton per coil. In addition, dimensional requirements to the TF coil are very tight from a view point of stable plasma confinement.
In the following section, features of the ITER TF coil are briefly introduced, and performance tests of manufacturing technologies such as welding processes are described, and typical results are summarized. In order to suppress welding deformation, combination method of Tungsten-inert gas welding (TIG) and beam welding (such as an Electron Beam Welding (EBW) and a Laser Beam Welding (LBW)) has been applied to a thick plate weld. Furthermore, process conditions of the EBW and LBW suitable for the thick plate have been investigated to improve work efficiency.