Speaker
Description
The KSTAR's NBI heating system achieves an output of about 5.46 MW, 8.7s through the 2017 KSTAR Campaign. The second NBI system (NBI2) has being installed to increase the output of the NBI heating system. The NBI2 system consists of one on-axis and two off-axis ion sources, and the maximum output is designed to be 6 MW based on the neutral beam output. The ion source of NBI2 is in the same form as the NBI1 ion source except: (1) the electrode terminal size of the source table has been enlarged, (2) the size of the ceramic part has been enlarged to improve the cooling efficiency of the filament feedthrough, (3) the beamlet aperture center of the G3 grid is moved in the outward direction in order to improve the transmission efficiency, (4) the G1 grid of the NBI2 ion source accelerator has been changed the bonding between the body and the manifold to prevent the problem of thermal deformation and clogging of the inner cooling channel which has been a problem continuously. To verify the NBI2 ion source produced, we will carry out the inspections and performance tests: (1) Thermal load test for G1 grid, (2) Thermal shock test of Bellows’s O-ring for grid cooling parts, (3) Hi-pot test in vacuum. Inspections include dimension inspection, leak test, pressure test, insulation test, and assemblability. In this paper, we will describe that inspections and performance results of KSTAR NBI-2 ion source by beam conditioning and the 2018 KSTAR Campaign.
