Structural analysis of the KSTAR toroidal field magnet system

The toroidal field (TF) magnet system of Korea superconducting tokamak advanced research (KSTAR) device consists of 16 superconducting coils enclosed in the steel cases. The TF magnet structure protects the winding pack from mechanical, electrical, and thermal loads, and also supports three pairs of poloidal field (PF) coils as well as four pairs of central solenoid (CS) coils. A three-dimensional finite element (FE) model including the winding pack, insulation and filler material has been developed using solid brick elements, and a hybrid model with beam-shell elements has been also built for the verification purposes. The structural reliability of the TF magnet system is investigated by performing various analyzes such as a global/local analysis, a detailed analysis, and a fatigue evaluation. The results reveal that the maximum stress intensities of the TF magnet structure are below the allowable stress limit and its fatigue life complies with the requirements of the design criteria, so it can safely withstand the reference scenario operations. In addition, the design loads obtained from analysis results can be used for the detailed structural design of other supplementary components.