Zeolite membranes were identified to be used in the future fusion reactors to separate traces of tritiated species from large helium flows. Due to the lack of data in the literature, separation experiments with helium, hydrogen and water vapor have been performed in the Tritium Laboratory Karlsruhe (Germany). The obtained results shall be used to predict performances at reactor scale. Therefore, a simulation tool of a permeator has been developed to perform calculations ab-initio of its performance at several experimental conditions. In the present work, numerical results for the binary mixture hydrogen/helium at different concentrations are compared with the experimental results obtained with a zeolite MFI-ZSM5 tubular membrane, where separation factors below 2 were measured for different cuts. Very good agreement between experiments and simulations was observed. This agreement gives confidence to integrate this numerical tool into a membrane cascade simulator, in development in the TLK, toward the modeling of the zeolite membranes' performances at reactor scale. (c) 2016 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.