Design and Development on the Remote Maintenance Tools and Strategy of the Port Closure Plate in DEMO

In the international thermonuclear experimental reactor (ITER) and the demonstration power plant (DEMO), there are three kinds of ports: the upper port (UP), the equatorial port (EP), and the lower port (LP). The applications and structures of the upper, equatorial, and LPs are different between those of ITER and DEMO. In DEMO, the breeding blankets (BBs) could be removed from the UP, a multipurpose deployer is transported and installed in the EP, and the divertor is maintained through the LP. It is noted that during remote maintenance (RM), the operating environment must be safe for the operators. To achieve this goal, reliable RM tools and RM strategies must be designed and developed. One of the containment barriers of the tokamak is the port closure plates (PCPs), which weighs between 1.3 and 25 tons depends on its location, and the PCPs need to be removed during the maintenance process. Therefore, in this article, the current designs of the PCPs are first presented. Then, the RM tools in both commercial and research stages are studied for the RM of the PCPs. Next, the RM strategies are designed and developed for each port. Finally, suggestions for the development of different RM tools are proposed.