Design Study of Vacuum Vessel Concepts for COMPASS-U Tokamak

COMPASS upgrade (COMPASS-U) is a high-magnetic field, medium-sized tokamak with high-temperature (<; 500 °C) operation. The scientific program is aimed to address the topics of plasma exhaust, liquid metals, enhanced confinement modes, and edge plasma physics. The plasma current is up to 2 MA and the toroidal magnetic field is up to 5 T. Therefore, plasma disruptions can produce large electromagnetic forces on the vacuum vessel (VV) and other conducting structures. This article presents the study of different VV design concepts, which were considered during the COMPASS-U conceptual design phase. This article describes the electromagnetic forces exerted during plasma disruption, high-temperature operation requirements, and other design constraints. INCONEL 625 is selected as a reference material for VVs. FE simulations of the 45° sector of the vacuum vessel were carried out for various load combinations. This article summarizes the wall thickness optimization that limits the vessel deformation and minimizes the stress in the shell. The results are broken down into different categories of stress according to the ASME code and compared with material limits.