Status of design of the first wall for ITER

Abstract

The First Wall (FW) is one of the key components of the International Thermonuclear Experimental Reactor (ITER). It must be designed to remove the surface heat flux from the plasma, while, in combination with a structurally integral shield, reduce the nuclear effects in the vacuum vessel and protect the superconducting coils from excessive nuclear heating and radiation damage. As the principal plasma facing element it will be exposed to the 1500 MW fusion power at an average neutron wall loading of about 1 MW/m2 and must be designed for a life of 0.3 MWa/m2 during the Basic Performance Phase. In addition the First Wall must successfully withstand peaked thermal and electromagnetically loads resulting from plasma disruptions.A conceptual design of the ITER First Wall has evolved as a result of the Engineering Design Activity. This design utilizes a beryllium plasma facing layer, bonded onto a copper layer which conducts the heat to the contained active cooling tubes. The copper is bonded to stainless steel for structural support and attachment to the water cooled stainless steel shield section. As discussed in this paper, the basic FW configuration developed for use at most locations, referred to as the primary wall, must be modified for different power requirements at two specific locations, the plasma limiter and the baffle. Carbon Fiber Composite (CFC) is being considered as an alternative material for the baffle and limiter FW because of its high thermomechanical performance and its high resistance to thermal shock.