Nuclear shielding design study for JT-60 Super Upgrade

The nuclear shielding design for the vacuum vessel of the JT-60SU has been studied for deuterium operation. A low activation material, Ti-6Al-4V, is proposed through a design study. A 25-40 cm thick water tank-type vacuum vessel using Ti-6Al-4V and boron (1% of /sup 10/B) doped water are shown to be the best choice. This design concept gave results consistent with the design requirements: the one-turn resistivity of the vacuum vessel is /spl sim/50 /spl mu//spl Omega/, and the dose inside the vessel is /spl sim/15 mrem/h a year after the shutdown. The total nuclear heating of the whole TF coil can be reduced to /spl sim/11 kW for a D-D fusion neutron rate of 1/spl times/10/sup 18//s.