Electromagnetic model for finite element analyses of plasma disruption events used in the design phase of the COMPASS-U tokamak

Abstract

Large electromagnetic forces acting on the vacuum vessel and passive stabilizing plates of the COMPASS-U tokamak (R = 0.894 m, a = 0.27 m, BT ≤ 5 T, IP ≤ 2 MA) due to disruption events are expected during its operation. An electromagnetic model based on the finite element method was developed using ANSYS software to determine the maximal possible forces on the vacuum vessel assembly that might occur. The effects of current quench, thermal quench, vertical displacement events and halo currents are all incorporated in the model. The toroidal eddy currents, the poloidal eddy currents (caused by thermal and current quench) and the poloidal halo current are taken into account. The model predicts that the induced toroidal current can reach the value up to 1.33 MA in the vacuum vessel shell and the value up to 0.52 MA in the passive stabilizing plates. Vertical force up to 4.1 MN acting on the entire vacuum vessel assembly can be expected and force up to 2 MN acting on the stabilizing plates, in particular. The results of the presented electromagnetic model are part of the load specification for the mechanical design of the vacuum vessel assembly of the COMPASS-U tokamak.