Experiment of Recovery of Tritium from Li by Y and Design of Hot Trap

The recovery of tritium, T, from neutron-irradiated Li by a Y plate was experimentally investigated, and a Y hot trap was designed to remove T from a flowing Li target loop of IFMIF. T generated in Li ranging from 0.01 to 0.05ppm in molar fraction was successfully removed by a Y plate at 300-500°C. The ratio of recovered T to generated one increased with temperature and immersion time. HT was the main chemical species of T that was released from Li, while HTO was the main one without Y absorption. SEM-EDX analysis revealed the transfer of not only T but also O originally included in Li as an impurity. Treatment of Y by HF was effective to remove oxides formed on the as-received Y plate and enhanced its hydrogenating rate. Conditions of a Y hot trap designed for the flowing Li target loop of IFMIF are given in the present paper.