Deuterium retention and desorption behavior of lithium titanate

Solid breeding material, lithium titanate (Li2TiO3), employed for a solid breeder blanket, was irradiated by 1.7-keV deuterium ions to investigate an amount of retained deuterium and desorption behavior of deuterium. Dependence of deuterium ion fluence on the amount of retained deuterium was also obtained. Similar experiments were conducted for Li and Ti in order to examine a trapping mechanism of deuterium in Li2TiO3. Deuterium implanted to Li2TiO3 desorbed in forms of HD, D2, HDO and D2O. The amount of deuterium desorbed in form of HDO was largest in these gas species. The desorption peak appeared at 600 K, but significant desorption up to 900 K was observed. The temperature in the solid breeder blanket ranges from 550 K to 1200 K. The present result suggests that the tritium produced at low temperature region is not completely desorbed during the operation. Thus, a spatial distribution of temperature in the blanket has to be controlled for the tritium to be easily desorbed. The desorption spectra of deuterium in Li2TiO3 were similar to those of Li. This suggests that most of implanted deuterium is trapped in form of Li-D and Li-OD.