Fabrication and Characterization of Li2TiO3–Li4SiO4 Pebbles for Tritium Breeder

Lithium based ceramics have been regarded as the promising ceramic breeders of the test blanket modules. As lithium burn-up of ceramic pebbles in the fusion reactor will be limited to about 15 % due to Li transmutation. The phase and composition (Li+ transferring process) of Li2TiO3–Li4SiO4 ceramic pebbles with a certain amount of Li loss (−xLi2TiO3 and −xLi4SiO4, x = 0, 5, 10, 20 %, molar ratio) were simulated by thermogravimetry and differential scanning calorimetry and X-ray diffractometer for the first time. The results showed that the Li+ of Li4SiO4 could move to Li4Ti5O12 to form Li2SiO3 and Li2TiO3 as the octahedral (16c) sites of Li4Ti5O12 are empty. In order to tailor the properties for optimization, 20 % Li2TiO3–80 % Li4SiO4 pebbles were fabricated by a graphite bed process. In combining these materials, the pebbles obtained reasonable pores, small grains, and relative high crush load.