Development of bolting tool for remote handling of ITER first wall central bolt

This article presents development of remote handling tool for FW central bolt tightening and its demonstration of the functional requirements in prototype testing. A compliance mechanism was newly designed and successfully demonstrated for the capacity to handle the misalignment of the thread part and to withstand 10 kN m torque. Maraging steel wrench with out-of-standard Torx bit was designed and fabricated. Irradiation test of the maraging steel material, in which corrosion was found at the total dose 0.3MGy, is also reported.