Structural analyses and preliminary design of HT-7U cryostat

The cryostat of HT-7U Tokamak is a large vacuum vessel surrounding the entire Basic Machine with cylindrical shell, dished top and flat bottom. The main function of HT-7U cryostat provides the thermal barrier between the ambient temperature testing hall and the liquid helium cooled superconducting magnet. The loads applied to the cryostat are vacuum pressure, dead weight, seismic events and electromagnetic forces originated by eddy currents. It also provides feed through penetrations for all the connecting elements inside and outside the cryostat. The main material selected for the cryostat is stainless steel 304L. The structural analyses including buckling for the cryostat vessel under the plasma operation condition have been carried out using finite element code. Stress analysis results show that the maximum stress intensity was below the allowable value. In this paper, we emphasize on the structural analyses of HT-7U cryostat. The preliminary design of the cryostat is also described.