Analytical study of electromagnetic forces induced by eddy current in ITER divertor

It is a key issue to design robust divertor modules for the International Thermonuclear Experimental Reactor (ITER). The divertor module, which consists of a cassette body with high heat flux components, has to be designed to handle not only severe particle fluxes and thermal loads from the main plasmas, but also various electromagnetic forces during the operations. In particular, the electromagnetic force induced by eddy currents during plasma disruptions is the most severe condition from engineering design point of view. Based on the ITER disruption scenarios, dynamic electromagnetic forces of the divertor module induced by the eddy currents have been analyzed. To simplify modeling, the actively cooled structure made of copper alloys was considered because of its much lower electrical resistivity compared to the other materials. In the analyses, parametric studies related to electrical connections, divertor cassette configurations and disruption scenarios, have been considered. Based on the electromagnetic force analyses, elastic stress analysis has also been performed. In particular at the vertical displacement event, analytical results show that the maximum force over 5 MN/m(2) which corresponds to the elastic stress of as high as several hundreds MPa is expected in the divertor high heat flux components and that some design modifications for the mitigation of the electromagnetic force will be necessary.