Tokamak Remote Control In-vessel Inspection Manipulator Structure Design

Tokamak is the experiment device for controlled nuclear fusion research, in which high energy plasma is constrained by toroidal magnetic field for heating to reaction temperature. Toroidal vacuum vessel inside Tokamak is formed by the first wall made up by special material tiles, directly exposed to high energy particles. These first wall tiles may get damaged during high energy plasma experiment, therefore a periodical examination of first wall is necessary to ensure safety.This paper proposes a ten DOF remote control in-vessel inspection manipulator for Tokomak’s toroidal first wall maintenance work. The flexible manipulator uses its special four-part structure of movable platform, spreading big arm, inspection small arm and end effector(binocular vison module) to perform complicate inspection work of first wall tiles. The design of inspection manipulator mainly deals with large toroidal space coverage, high temperature high vacuum high radiation in vessel environment adaptation, narrow entrance for manipulator, as well as inspection efficiency and reliability. As primary part of inspection manipulator, the stiffness of spreading big arm will affect its inspection task quality greatly. The PEFT interlayers for high temperature and high vacuum lubrication have large effect on big arm’s stiffness; optimized design of lubrication interlayer can improve quality of inspection work largely. A scale 1 mock-up model of Tokomak is built in the lab to test the 10 axes movement and validate its vacuum vessel entrance ability, and then provides optimization plan for later adjustment for the project.