Design and structure analysis of the HT-7U vacuum vessel

The vacuum vessel of the HT-7U superconducting tokamak has a full welded structure with double wall which will be filled with borated water is used for neutron shielding, non-circular cross-section is used for plasma elongating, horizontal and vertical ports are used for diagnosing, vacuum pumping, plasma heating and plasma current driving, etc. The vacuum vessel consists of 16 segments. It will be baked out at 250 °C and plasma facing components (PFCs) baked out at 350 °C to get a cleaning wall. When the machine is in operation, hot wall (vacuum vessel wall is around 100 °C and first wall is around 150 °C) and cold wall (vacuum vessel wall and first wall is in normal equilibrium temperature) are both considered. The stress caused by thermal deformation and electromagnetic (EM) loads caused by 1.5 MA plasma disrupt in 3.5 T magnetic field are important in the design of the HT-7U vacuum vessel and PFCs. Finite element method was accepted for structure analysis of the vacuum vessel.