Detailed design and fabrication method of the upper and lower ports for the ITER vacuum vessel

The detailed design of the vacuum vessel port structures has been developed based on the conceptual design of the ITER IT (international team) and PT (participant team). The special emphasis was laid on the flange joint between the port extension and the in-port plug to develop the design of the upper port. The structural analyses of the lower RH port have been also performed to verify the capacity for supporting the VV. The fabrication method and the sequence of the detailed fabrication for the ports are developed focusing on the cost reduction as well as the structural simplification. Tolerance study has been performed to avoid the mismatch of each fabricated component and to obtain the suitable tolerances in the assembly at the shop and site. From the several structural analyses and the development of the fabrication method, the upper and lower port designs have been improved and it also complies with the design specification.