Thermal Loading of DEMO Divertor Cassette During Maintenance Conditions

In this paper thermal loading on the divertor cassette of the DEMO fusion reactor during maintenance conditions is analyzed. Thermal radiation and decay heat in activated structure material are the main heat transfer mechanisms contributing to the cassette heating. Before carrying out numerical simulations of the real case, the simulation accuracy of the thermal radiation model in the ANSYS CFX program is cheeked with simplified analytical example. The geometry of the analytical case (closed ring) tends to resemble the DEMO tokamak as far as possible but it is still simple enough to allow analytical solution. Finally, the thermal loading of the vacuum vessel during replacement of one divertor cassette is simulated with the ANSYS CFX using the baseline geometry of the most recent DEMO tokamak design with 54 divertor cassettes [1]. The simulation accuracy is appropriately evaluated.