Radiation-hard AC servomotor and O-ring development for the ITER blanket remote handling system

The ITER blanket remote handling system (BRHS) will be deployed into the vacuum vessel after plasma operations of ITER are halted for maintenance, and will handle the blanket modules, which can weigh up to 4.5 ton and be larger than 1.5 m, stably and with a high degree of positioning accuracy. The BRHS will operate in a high radiation environment as the in-vessel components will have been activated by neutrons. The dose rate is estimated to be up to 250 Gy/h and the ITER project requires 1 MGy of radiation hardness for the BRHS components.The BRHS is composed of mechanical, electrical, and optical components, the irradiation tests of which are still ongoing. This paper describes the irradiation test results of AC servo motor and O-ring as they are the most developed of the BRHS components. The BRHS will operate by using AC servomotors whose insulating and lubricant parts have been replaced with radiation hard materials. Irradiation tests confirmed the radiation hardness of the modified AC servomotors up to 10 MGy. Stationary parts of the BRHS will use O-rings to seal in lubricant grease; therefore a new rubber compound was developed to increase the radiation hardness and oil resistance of these O-rings. The radiation hardness of new rubber compound was confirmed up to 3 MGy via irradiation testing. The O-rings of the new rubber compound underwent leak testing, the result of which are described in this paper.The 18th International Conference on Fusion Reactor Material