HT-7U vacuum vessel

The HT-7U superconducting tokamak is under construction. It is expected to complete the fabrication and installation in the next 2–3 years. Overall configuration of the device is described in other paper. The vacuum vessel is full welded with “D” shaped cross-section and double wall. It consists of 16 segments and supported by eight flexible multiple plate supports. Ports are distributed at top, bottom and middle plan. Low stiffness supports, and two sections of bellows on each port allow the vacuum vessel can move a little in radial direction to accommodate the expansion during the vessel bake-out to 250 °C. Some R&D of the vacuum vessel is completed, and fabrication is in progress.