Li vaporization properties of candidate materials for tritium breeder with high Li density

Highlights: • Li vaporization properties of sintered bodies of Li₂TiO₃, Li₈ZrO₆, β-Li₅AlO₄ and mixture of these phases are investigated. • Li₂TiO₃ is stable during the thermal annealing at 900 °C. • Li₈ZrO₆ is decomposed to form Li₆Zr₂O₇ and Li₂ZrO₃, and Li₅AlO₄ is decomposed into LiAlO₂. • β-Li₅AlO₄ and two-phases of β-Li₅AlO₄-Li₂TiO₃ and β-Li₅AlO₄-Li₈ZrO₆ have potential as a new advanced tritium breeder. - Abstract: Lithium vaporization properties of sintered compacts of single-phase Li₂TiO₃, Li₈ZrO₆, β-Li₅AlO₄, and two-phase β-Li₅AlO₄-Li₈ZrO₆ and β-Li₅AlO₄-Li₂TiO₃ are investigated. Li vaporization rates from the sintered pellets are measured by gravimetric methods, and crystalline phase changes are analyzed by X-ray diffraction. Li₂TiO₃ is stable during thermal annealing at 900 °C. In contrast, Li is evaporated from the other materials, and β-Li₅AlO₄ and Li₈ZrO₆ are, respectively, decomposed to LiAlO₂ and a mixture of Li₆Zr₂O₇ and Li₂ZrO₃. Considering the high Li density, which is estimated from the Li vaporization rate and initial Li density in the pebble, and appearance stability, the sintered compacts of single-phase β-Li₅AlO₄ and the two-phase materials β-Li₅AlO₄-Li₂TiO₃ and β-Li₅AlO₄-Li₈ZrO₆ have the potential to be applied to new advanced tritium breeders with high Li density.