[en] The migration of individual radionuclides in a porous medium were hydrodynamic dispersion takes place and where the radionuclides in the matrix of solid medium by diffusion has been calculated for a variety of cases. The cases center around the main case in the second KBS study on spent fuel. The main differences from the KBS study is the inclusion of matrix diffusion and the use of large dispersivities. The effluent rates of 23 important nuclides are presented as functions of distance and time for various values of important parameters such as rock permeabilidiffusion coefficients, release rates, time of first release, fissure spacing and longitudinal dispersion coefficients. (Authors)