[en] A nuclide migration device called RADMIG, which can simulate the high level radioactive waste (HLW) repository environments, was designed and manufactured for further suitability evaluation of Gaomiaozi bentonite as the buffer/backfill materials of a HLW repository in China through adsorption and diffusion experiments. It also can be used for granite, the host-rock of the HLW repository in China. The design parameters are: pressure: 1-5.0 MPa; temperature: ambient ∼100 degree C; Eh: ≤-200 mV. The blank test results show that RADMIG can work steadily under any environments in the range of design parameters. And the migration experiments are in progress. (author)