Conceptual design of 5 MW-NBI injector for HL-2 M tokamak

•A completely new tokamak HL-2M is now being under construction in Southwestern Institute of Physics in China now.•As one of the main auxiliary heating systems for HL-2M tokamak, a new 5MW-NBI beam line based on 4 sets of 80kV/45A/5s bucket ion sources is conceptually designed.•The preliminary structure and layout of key components are determined.•Beam power transmission efficiency is calculated with geometrical algorithm.