Analysis of Existing and Proposed Maintenance Deployment Systems Toward DEMO MPD Development

This article reports on a study of previously existing or proposed maintenance deployment systems with similar functions and structure to that of the proposed multipurpose deployer (MPD) for demonstration (DEMO fusion power plant project). The current MPD design iteration consists of a boom deployment system that is ~30 m long and can support a payload of ~1000 kg, while still being able to access the DEMO vacuum vessel through a 2.78 m high by 1.08 m wide port. The purpose of this work is to benefit from previous experience by comparing the mechanical attributes and performance of systems as well as their advantages and disadvantages and any issues encountered to bring design input to MPD design development. The following systems were investigated: Joint European Torus (JET) in-vessel remote handling booms, telescopic articulated remote mast (TARM), Next European Torus (NET) experimental device for in-torus handling (EDITH), Tokamak Fusion Test Reactor (TFTR) Maintenance Manipulator, and Snake-like Robot Arms in Nuclear Environments. Systems that are currently in development for ITER and Chinese Fusion Engineering Test Reactor (CFETR) were also investigated according to their latest available design iterations. This article concludes that these systems, comprising of articulating links to form long-reach slender structures, give rise to challenges with their payload, stiffness, and control. The straight boom style system would be the most suitable design for the current tasks that a DEMO MPD is expected to perform. However, there is no particularly strong candidate without first fully defining the requirements and constraints that a DEMO MPD must adhere to.