This paper describes the system being designed to study the processes of hydrogen isotopes (or their mixtures) interaction with a solid body at pressures up to 500 MPa. Hydrogen isotopes pressure is produced by a thermodesorption source based on vanadium dihydride. Gas is sampled through an intermediate volume. Cias chromatograph is used to analyze the gas for isotopic composition. Possibility of the system development is exemplified by temperature dependencies of equilibrium desorption pressures for vanadium dihydride in a pressure range up to 500 MPa obtained using available equipment.