Tritium recovery from blanket sweep gas via ceramic proton conductor membrane

Electrochemical hydrogen pump can extract hydrogen isotopes selectively from a blanket sweep gas, because one of its driving forces of hydrogen transportation is electric potential difference. In this work, transportation properties of multi-component hydrogen isotopes including tritium were investigated experimentally. Ceramic proton conductor membrane used in this work was SrCe0.95Yb0.05O3−α made by TYK Co. H2–D2 mixture balanced with He was supplied to the hydrogen pump, that was kept at 873 K and applied the voltage between 0 and 1000 mV, and the permeated gas was analyzed with a gas chromatograph. The rate-determining step of hydrogen transfer via ceramic membrane seems to be close to the diffusion step in the bulk of ceramic with increase of the applied voltage. HT–H2 mixture balanced with He was also supplied to the hydrogen pump, and recovery of tritium via ceramic membrane was done. Diffusivity of hydrogen in the proton conductor ceramic is larger than that of tritium. Hence, hydrogen is enriched in the gas of the permeation side. In this experimental condition, about 40% of tritium supplied was recovered and the decontamination factor was 1.5.