Manufacturing Design Assessment of the Welded In-Wall Shield Rib for ITER Vacuum Vessel

Between inner and outer shells of vacuum vessel, numerous in-wall shielding (IWS) blocks are installed to provide neutron shielding. Uniquely, the IWS ribs in sector 1 and 6 are manufactured by welding and its manufacturing design shall be secured for not only manufacturability but safety point of views. For the design of IWS ribs, complex loads for multiple directional electromagnetic force, coolant pressure, and earthquake shall be considered simultaneously. Moreover, in-service inspection (ISI) is impossible after commissioning ITER, and therefore, proper design assessment procedure should be applied with reasonable conservatism. In this paper, an approach for manufacturing design of welded IWS ribs is proposed. On the basis of that approach, four representative models are screened by geometric factors and load magnitude. Under the most conservative loads among multiple loading conditions, structural safety of each representative models is verified with RCC-MR. The deviation requests for this assessment were approved to IO and ANB. This approach and results could be used as a reference for the design of vacuum vessel components, which is impossible for ISI.