The development of a radionuclide transport model for a tunnel of a repository for short-lived low and intermediate level waste is presented in this work. The model is two-dimensional and uses the finite element method to describe a cross-section perpendicular to the tunnel's main axis. It is shown that the use of a realistic geometry of the system, albeit in 2D, results in a transparent model that can handle the equations in a flexible way. The geometry can easily be changed and also extended to a 3D representation without affecting the numerical code. The disadvantage is the computational requirement. It is expected however that radionuclide transport modelling will evolve to 2D or 3D representations that are more realistic and transparent than today's 1D analytical models which involve many simplifications whose impact on the output is difficult to evaluate.