Numerical Investigation of Electromagnetic Forces on Tokamak Fusion Reactor System During Quench Event

The performance improvement in high-temperature superconductors (HTS), particularly rare-earth barium copper oxide (REBCO), and the introduction of no-insulation (NI) winding technique have enhanced the capabilities of HTS magnets. These performance enhancements are expected to realize plasma confinement under high magnetic fields in fusion reactors. Subsequently, fundamental experiments on fusion REBCO magnets are progressing rapidly. Tokamak fusion reactors are equipped with several toroidal field (TF) magnets arranged in a toroidal configuration. At steady state, these magnets are balanced by each other's magnetic attractive force. In tokamak fusion reactors, a problem has been pointed out that imbalance electromagnetic forces arise among the TF magnets during a quench event, especially for NI magnets. In this paper, the electromagnetic forces acting on the TF magnet are simulated under poloidal magnetic fields during the quench events. As the simulation results, large currents are induced reaching to the critical currents. A large imbalance electromagnetic force, a maximum of approximately 120 MN, is observed. The imbalance force is concentrated depending on a portion in TF magnets, because the torsional forces due to the PF magnetic field is added to the electromagnetic forces between the TF magnets.