Thermal Analysis of the Vertical Target for the ITER Divertor Design

Abstract

Monoblock tile design for the vertical target of the ITER is used for the utilization of the high density power from the tokamak plasma. The presented thermal analysis of the vertical target subjected to highly concentrated (q0 ap 382 MW/m2) near normal heat load demonstrates the developed code high ability to perform the transient thermal analysis on 2-D models with the complex nonlinear boundary conditions and makes it possible to draw the following conclusions: the concentrated heat load onto the vertical target tile causes the erosion of the plasma facing tile surface; about 20% of the incident heat load is lost by material evaporation and radiation from the vertical target external surface, by this way helping to relieve slightly cooling channel from the heat load. The main purposes of the paper are (a) to present the mathematical model, which makes possible to simulate the following peculiarities of the discussed problem: the tile surface erosion due to evaporation resulting in evolution of the loaded surface profile; redistribution of the temperature field and heat fluxes inside the vertical target body due to highly concentrated lateral heat load and surface burn-out; heat lost by radiation; shifting of the heat removal mode closer to critical heat flux (CHF); and (b) basing on the thermal analysis performed by the developed code to investigate possible consequences of a tile failure to avoid the cascade effect during transients.