Research and development of remote maintenance equipment for ITER divertor maintenance

Takeda, Nobukazu; Kakudate, Satoshi; Nakahira, Masataka

To facilitate easy maintainability, the ITER divertor is divided into 60 cassettes, which are transported for replacement using the remote equipments. The cassette of 25 tons has to be transported and installed with a positioning accuracy less than 2 mm in the limited space under the intense gamma radiation field. Based on these requirements, the following design and tests were performed. (1) Link mechanism was studied to apply to the transportation. A compact mechanism with links is designed through the optimization of the link angle taking account of space requirement and force efficiency. The lifting capacity of 30 tons has been demonstrated. (2) Compact link mechanism was also studied to apply for locking of the cassette. The final positioning accuracy of 0.03 mm for installation from the initial positioning error of 5 mm has been demonstrated. (3) Sensor-based control of the remote equipment was tested using simple sensors. It is found that the positioning accuracy of 0.16 mm has been achieved and this value is sufficient.