Design progress of the ITER in-wall shielding

Morimoto, Masaaki; Ioki, Kimihiro; Terasawa, Atsumi; Utin, Y.*

The ITER in-wall shielding is mounted in between the double walls of the Vacuum Vessel. Boron-doped stainless steel and SS430 ferritic steel are used. The design improvement of the in-wall shielding has focused on reducing electromagnetic forces acting on shielding blocks. It has been found that the calculated electromagnetic forces have been significantly reduced. Magnetization forces have also been calculated for ferromagnetic inserts. Based on these load conditions, structural analyses have been performed and structural integrity has been validated. Shapes of boron-doped shielding plates which have low ductility are carefully designed to prevent excessive stress concentrations and not to take high mechanical loads. This makes shielding plate design simpler and more robust. Suitable dimensions and gaps between shielding blocks and between shielding block and the VV have been designed to fit to tolerances of the VV.