In this paper, we introduce a set of low-pressure palladium membrane diffuser designed to recover hydrogen isotopes from inert mixture gases. Several gaseous mixtures (D-2/Ar and D-2/He) with different deuterium concentration have been used for cleanup test of the low-pressure palladium membrane diffuser at 723 K. Effect of the composition of feed gas on the pressure of permeate side has been observed by gas chromatography (CC) and pressure sensor. With the feed flow rate of the mixture gases increasing, the D-2 permeate pressure is increasing as well. Decontamination factor (DF) of more than 1000 and recovery efficiency greater than 99.9% have been obtained by controlling the feed gas flow rate. The same palladium membrane diffuser was used to process helium-3 gas with more than 10% hydrogen isotope and about 0.3% tritium gas. The pure helium-3 (above 99.4%) with low content of hydrogen isotopes (about 0.084%) has been obtained. Recovery efficiency of all hydrogen isotopes is 99.5% above. (C) 2008 Elsevier B.V. All rights reserved.