Effects of structural and electromagnetic loads on vacuum vessel of Pakistan spherical Tokamak

Abstract

Abstract This paper focuses on the effects of electromagnetic and structural loads on the vacuum vessel (VV) of Pakistan Spherical Tokamak (PST). The configured MAXWELL 3D and ANSYS Mechanical suits are used to investigate the different variables for structural analysis. The simulation is performed for transient current excitation of all coils and major plasma disruption, respectively. The electromagnetic (EM) loads derived from MAXWELL 3D are directly imported to the ANSYS Mechanical where structural loads are also assigned to VV. Stresses and deformations were determined from the associated loads. The 30° section of the VV with all coils is modeled in the design modeler and its step file format was imported to MAXWELL 3D. The section model was based on the axial symmetry of all coils system. By changing the thickness of inner cylinder of VV, the EM effects were studied. The variation of EM force, eddy current, and heat generation due to eddy current were studied with time for different thicknesses of the inner cylinder. As the thickness of inner cylinder decreases from 8 mm to 3 mm the magnitude of eddy current is observed to decrease uniformly for both cases (all coils and plasma disruption). The EM effect was found very strong in the case of coils transient. The results were compared using the design criterion of the RCC-Mx standard. It showed that PST geometry is safe, even 3 mm thickness of its inner cylinder can tolerate current transients of coils and associated dead loads based on the design criterion of the standard.