Simulation of Electromagnetic Transients in ITER Thermal Shield Manifolds

A study of eddy currents and forces associated with electromagnetic (EM) transients for the event of current quench in the ITER thermal shield manifolds is presented. EM response of the tokamak passive structures with respect to their inductive coupling has been estimated using the shell approximation. The external field obtained within the model, assuming their 40-degree symmetry, has been applied to the local model of the thermal shield (TS) manifolds covering the 360-degree domain. Fields sources are modeled accurately to the input data description. At this stage of the study related to first estimates of EM loads, acting on the TS manifolds, the electric contact between the cooling tubes and adjacent TS plates was neglected. The current flow is restricted between the neighboring panels. Such simplification uncouples galvanically the manifold tubes from other TS conducting shells, which makes possible a local simulation of eddy currents and EM loads on the manifolds. Two design options with/without electrical breaks in outlet manifolds have been considered. Detailed temporal and spatial distributions of eddy currents and EM forces were obtained. The simulated results were validated in a comparison with a lumped equivalent circuit. Maximal EM loads per unit length were evaluated and found to be low.