Characteristic of tritium release from LiTiO under D-T neutron irradiation

Edao, Yuki; Kawamura, Yoshinori; Ochiai, Kentaro; Hoshino, Tsuyoshi; Takakura, Kosuke; Ota, Masayuki; Iwai, Yasunori; Yamanishi, Toshihiko; Konno, Chikara  

Tritium generation and recovery studies on LiTiO as a solid breeding material under neutron irradiation carried out in the Fusion Neutron Source (FNS) facility. A capsule with LiTiO packed bed was put in a system which simulated an actual blanket system which built in beryllium blocks and lithium titanate ones. Estimated values of the amount of tritium generation by a numerical calculation agreed closely with experimental values. The capsule was heated up to 300C, and helium, helium with water vapor, hydrogen or hydrogen/water vapor were selected as purge gas. In the case of purge by helium added water vapor, the ratio of HTO to total tritium release was 98%. In helium with hydrogen/water vapor purge, the ratio of HTO to total tritium release was 80%, which was confirmed that HTO released by isotope exchange reaction between water vapor and tritium. In helium with hydrogen purge, the ratio of HT to total tritium release was 6070%, which was shown that HT released by isotope exchange reaction between hydrogen gas and tritium. HTO released by water generation reaction between hydrogen in purge gas and oxygen in LiTiO although water vapor was not added in purge gas. The ratio of HTO release seemed to be small under the deoxidized condition of the LiTiO surface. Tritium release behavior in the LiTiO depended on the composition of purge gas, and its chemical form was affected by the surface conditions of LiTiO.