Hardening inspection devices to ultra-high vacuum, temperature and high magnetic field

In order to demonstrate the feasibility of a mini-invasive inspection arm in ITER, the next step in fusion energy research machines, and to match the need for such a device in the French tokamak Tore Supra, a hardened long-reach robot has been developed by the CEA-LIST robotics team. The AIA (Articulated Inspection Arm), a 8 m long, highly articulated dexterous carrier with a 10 kg payload has been developed to be deployed anywhere in the Tore Supra vacuum vessel from one single ∅ 250 mm entry point, while the vessel is kept at the operating temperature (120°C) and pressure (10^-5 Pa). Since its successful demonstration in Tore Supra in September 2008, the robot has been identified by different teams of scientists working on the tokamak for various potential tasks, from vision to diagnostic calibration or component analysis. In order to make such a device even more available, the CEALIST team is now working on the magnetic field constraint on robots. The goal being to demonstrate capabilities of intervention in ITER conditions, the considered field is 4 to 8 T. Technologies, command schemes and design strategies available for an inspection robot tolerant to high magnetic field have been studied. This paper first details the different technologies chosen for the AIA. How such an inspection device has been integrated on a multidisciplinary research machine such as Tore Supra is then detailed in a second part. The paper finally presents various concepts and experimentations to be used in a magnetic field tolerant robot for inspection of a large superconductor machine.