Membrane separation by zeolite membranes has been proposed as a pre-concentration stage for the tritium extraction from the purge helium of the breeding blanket combined with a final recovery by the catalytic membrane reactor PERMCAT. This fully continuous operation improves the tritium management in fusion machines, minimizing the tritium inventory. In this work permeation measurements for mixtures of hydrogen, helium and water vapor at different compositions are presented.  In parallel the first results of a simulation work comprising a model for multistage separation, allowing scaling up towards DEMO application, are discussed.