Welding technology R&D on port joint of JT-60SA vacuum vessel

This paper focuses on one of the JT-60SA vacuum vessel manufacturing R&D, onsite welding technology of the port joint. The work space is limited inside the vessel, and manipulator application is examined through the simulation and the mock-up trial. As a result, the most difficult port of the upper vertical is successfully weld-jointed. The quality as the product joint and the controllability of the manipulator are assured and perspectives to the other ordinary port joints are discussed with issues gained from this R&D.