Fabrication and characteristics of lithium metatitanate tritium breeder via polymer-assisted sedimentation method under different sintering conditions

Abstract Helium-Cooled Pebble-Bed (HCPB) will be chosen as the preferred Test Blanket Modules (TBMs) in International Thermonuclear Experimental Reactor (ITER) and DEMO fusion reactor. Lithium metatitanate (Li 2 TiO 3 ) ceramic pebbles are proposed as one of promising candidates of solid-type breeder blanket for the outstanding comprehensive performance. Previous fabrication methods still need to be improved on the mild preparation condition, uniform diameter, and high sphericity. In this paper, an improved wet process for pebble fabrication based on polymer-assisted sedimentation is employed. Gel pebbles are formed by dropping the slurry droplets into hot viscous liquid, and the spherical drops are solidified by polymerization reaction inside the droplet during sedimentation. In sintering process, the relationship between the sintering condition and crystalline structure of Li 2 TiO 3 is carefully discussed. Li 2 TiO 3 condensation and phase transitions are studied in particular. Finally, the optimal sintering temperature and time have been determined. This method could meet requirements for industrial mass production of the Li 2 TiO 3 pebbles, due to the mild preparation conditions, simplified transfer and purification process.