[en] Model experiments were carried out to investigate the generation of radiolysis gases in inactive bitumen salt mixtures by external γ-irradiation (10-100 MR). The amount of gases induced is proportional to the applied dose, their main component is hydrogen. Its specific rate of generation (appr. 1 x 10^-2 cm³ MR^-1 per g bitumen) is almost inependent of the type of bitumen and the composition of the salt mixtures, respectively. In separate experiments the diffusion parameters of hydrogen were determined in bitumens salt mixtures. Their H₂-sorption capacity is low (3.2 x 10^-3 cm³ g^-1), while the rate of H₂-permeation in these matrices (2.3 x 10^-9 cm³ s^-1 cm^-) is large, compared with its estimated rates of generation. (orig.)