IFMIF-EVEDA progresses in Japan as one of the EU-Japan Broader Approach Activities. The research is performed to decide whether or not IFMIF is constructed after some uncertainties included in the design are clarified. One of the uncertainties included in the Li purification process is to prove experimentally the removal of 1 weight ppm (wppm) T and 10 wppm D from flowing Li for safety.

Our research group is experimentally investigating the recovery of hydrogen isotopes including T not only in static Li but also in fluidized Li. In the past study, hydrofluoric acid (HF) treatment of Y is successful in removing oxide inevitably formed on its surfaces. The recovery of hydrogen isotopes including T less than 1 wppm is successfully proved with use of the HF-treated Y at 300°C, which is the IFMIF hot-trap temperature. Mass-transfer rates of hydrogen isotopes in the liquid Li and Y under stirred conditions were determined.

In addition, we developed a way to determine an amount of D or T dissolved in Li and Y by using a dissolution method. The quantitative D analysis is performed by using techniques of HNO3 solution for Y and H2O one for Li. The distribution coefficient between Li and Y is determined as a function of temperature and contact time.