Design and analysis of the Agile Robot Transporter for ITER in-vessel maintenance

In-vessel maintenance of the ITER tokamak machine needs to be carried out remotely as the radiation level inside the vacuum vessel (VV) is high for human workers because of the activation caused by the neutrons generated from fusion reactions. There are neutron diagnostics measuring the neutrons within the VV that need to be calibrated during initial assembly and operation phases that require remote handling of a neutron generator. This paper describes the design and analysis of the transporter of an in-vessel RH system called “Agile Robot Transporter (ART)” that is devised to handle a neutron calibration source and a dual arm manipulator. Its design is focused on agility to have better operational efficiency by reducing the number of port opening, less deployment/removal/operational time, efficient tool change, modular design for easy maintenance and decontamination. The design methodology is described starting from initial design, selection of commercial-off-the-shelf (COTS) components, identification of bespoke components, and iterative processes including mechanical design and analysis. Mechanical design is conducted based on the selected components while respecting the space constraints of the system itself and interfacing systems. The mechanical design includes cabling for the actuators and sensors, means for contamination protection, and modular design for maintenance. Iterative multi-body dynamic analyses by using the MATLAB/Simscape/Multibody and finite element analyses (FEA) by using ANSYS are carried out to find a feasible design solution. Maintainability assessment is conducted by showing the disassembly process.