Tritium recovery from blanket sweep gas via ceramic proton conductor membrane

セラミックプロトン導電体膜を介したブランケットスイープガスからのトリチウム回収

河村 繕範; 山西 敏彦

Kawamura, Yoshinori; Yamanishi, Toshihiko

電気化学水素ポンプは水素輸送の駆動力が電位差であるため、ブランケットスイープガスから水素同位体を選択的に取り出すことができる。本研究では、トリチウムを含む水素同位体多成分系での水素同位体の移動特性を実験により調べた。印加電圧の増加に伴い、物質移動の律速過程はセラミック格子内の拡散に近接していくように見える。HT-H系では、水素の拡散係数がトリチウムより大きいため、透過下流では水素が濃縮される。供給したトリチウムの40%が回収され、除染係数は1.5であった。

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. 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-H 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.