Engineering design of ion dump for EAST neutral beam injection system

Considering the working principle of the neutral beam injection system (NBI) for experimental advanced superconducting tokamak (EAST), the ion dump using calorimetric method with cooling tube inside was proposed to absorb the un-neutralized ions and measure the loaded energy. According to the physical characteristics of EAST NBI, together with the engineering limitation and requirement for measurement and cooling method, the detailed design decision of ion dump was given after the design performance indexes were analyzed, especially the dump board, including the material, design and arrangement of the cooling way inside. The proposed ion dump of V-shape with the cooling tube inside in this study was constructed and tested in the test bed of EAST NBI, and the feasibility of ion dump was proved by the experiment results under the working condition of 4 MW power and 10 s pulse length. This study lays a solid foundation to realize the experiment target of high power with high parameters and steady state for EAST NBI in the next step.