ITER-FEAT vacuum vessel and blanket design features and implications for the R&D programme

A configuration in which the vacuum vessel (VV) fits tightly to the plasma aids the passive plasma vertical stability, and ferromagnetic material in t he VV reduces the toroidal field ripple. The blanket modules are supported directly by the VV. A full scale VV sector model has provided critical info rmation related to fabrication technology and for testing the magnitude of welding distortions and achievable tolerances. This R&D validated the funda mental feasibility of the double wall VV design. The blanket module configu ration consists of a shield body to which a separate first wall is mounted. The separate first wall has a facet geometry consisting of multiple flat p anels, where 3-D machining will not be required. A configuration with deep slits minimizes the induced eddy currents and loads. The feasibility and ro bustness of solid hot isostatic pressing joining were demonstrated in the R &D by manufacturing and testing several small and medium scale mock-ups and finally two prototypes. Remote handling tests and assembly tests of a blan ket module have demonstrated the basic feasibility of its installation and removal.