Development of a water hydraulics remote handling system for ITER maintenance

ITER will be the next step fusion reactor. Owing to plasma interactions, some in-vessel components are expected to erode to such an extent that they will require replacement several times during the lifetime of the machine. As the irradiation of the torus structure forbids direct human access inside the vessel, all the nominal maintenance will be carried out with help of remote handling means. Hydraulic technology provides manipulators with very interesting payload/weight ratio in relatively small volumes when compared to electrical actuating technology. For that reason their use for maintenance application in space constrained areas like fusion reactors may provide interesting solutions. In addition operating in a fusion reactor requires a cleanliness level that oil hydraulics cannot ensure. Pure water hydraulics therefore proposes a good alternative. Indeed demineralised water self evaporates in case of leakage and cannot become radioactive after radiations exposure. This paper presents the complete MAESTRO system and gives an overview of the development activities currently carried out to adapt it to ITER hazardous conditions.