DESIGN OF THE ITER EDA PLASMA-FACING COMPONENTS

The design of the plasma facing components (PFC) in ITER has evolved w ith the detailed design of the reactor. The structures exposed to the plasma have different requirements according to their functions. The p rimary wall, surrounding most of the plasma along the last closed magn etic surface, is exposed to a moderate heat flux (0.5 MW m(-2)) but ha s to withstand the highest neutron load. The baffle wall is exposed to a peak heat flux of 3 MW m(-2) and to severe erosion from neutral par ticles due to their high neutrals pressure in the divertor. The limite r is subjected to the same loads as the primary wall during plasma bur n conditions and a higher peak heat flux (depending on its location) d uring the start-up and shut down phases when the plasma is leaning on its surface. The divertor vertical targets intercept the open magnetic flux surfaces near the separatrix and have to withstand the highest h eat flux and erosion in their lower part. The divertor dome is located directly below the null point and works in conditions similar to the baffle. The divertor wings receive similar thermal loads as the dome b ut can be subjected to high heat shocks and electromagnetic forces dur ing plasma disruption. The paper describes the solutions adopted for t he PFC and the results of analyses performed to validate the design. T he description is focused on the part of the PFC which is exposed to t he plasma. (C) 1998 Elsevier Science S.A. All right!; reserved.