Basic technology for Li enrichment using an ionic-liquid impregnated organic membrane

Hoshino, Tsuyoshi; Terai, Takayuki*

The tritium as a fuel for fusion reactors is produced by the reaction of lithium-6 (Li) with a neutron in tritium breeding material. However, natural Li contains only about 7.6% Li, and the enrichment of Li up to 30 - 90% is required for tritium breeding material in the fusion reactor. The mercury amalgam method is superior as one of the lithium isotope enrichment methods, and might be currently utilized in practice. In Japan, on the other hand, the development of lithium isotope enrichment methods using the ion exchange membrane and molten salt has been conducted to avoid the environmental pollution. However, the isotope separation coefficient and efficiency is too low in the case of these methods. Therefore, these methods were difficult to apply to mass production for the large need of fusion blanket. Preliminary experiments were conducted. Organic membranes impregnated with TMPA-TFSI and PP13-TFSI as ionic liquids were prepared, and the relationship between the Li separation coefficient and the applied dialysis electric current was measured. The results showed that Li isotope separation coefficient by this method (about 1.21.4) was larger than that by the mercury amalgam method (about 1.06).