[en] The tritium flow diagram within a fusion reactor may be splitted in a series of chemical engineering units. For them, the E.E.C. has launched a review program as well as experimental work. In this framework the CEA has carried out conceptual studies on fuel clean-up process, on gaseous waste treatment and on atmosphere detritiation systems. Moreover measurements with experimental loops are running to determine data necessary to assess unit dimensions; among others: hydrogen permeation rate through Pd-Ag membranes and tritium oxidation catalyst performances