Design, research and development for plasma facing components in JT-60SA

An overview of plasma facing components (PFCs) in JT-60SA is introduced, including the upper divertor, lower divertor, inboard first wall and outboard first wall. These PFCs are upgraded in four stages during a plasma experiment in JT-60SA. At stage one, only a partial inboard first wall and upper divertor are installed with graphite tiles and inertial cooling. At stage two, the remaining PFCs including the outboard first wall and lower divertor are installed, and the inboard surface is fully covered. At stage three, the vertical targets of the lower divertor are replaced with CFC monoblock targets and water cooling. At stage four, the whole carbon wall is replaced with a tungsten wall, and remote handling for the lower divertor is introduced. The research and development on major issues concerning PFCs are presented. Mock-ups of a CFC monoblock target were fabricated and it showed good heat removal of the expected maximum heat load of 15MWm-2 without degradation of the performance. Tungsten-coated samples were fabricated on the CFC and they showed no severe damage at surface temperatures of up to 2000 degrees C. Laser-welded samples showed good appearance and no defects were found by RT.