Optimization of mass-production conditions for tritium breeder pebbles based on slurry droplet wetting method

Highlights: • An automatic dispensing system was developed to improve uniformity and production rate of breeder pebbles. • The production rate of this system for Li₂TiO₃ pebble was estimated at 50 kg/year. • The optimization of dispensing and sintering conditions for the mass-production of Li₂TiO₃ pebble was conducted. • Integrity of Li₂TiO₃ pebble was able to be ensured during mass-production process, especially during batch process. - Abstract: Lithium metatitanate (Li₂TiO₃) is being considered as tritium breeding material for solid-type breeding blanket, which are used in pebble-bed form. The total amount of Li₂TiO₃ pebbles in Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) is approximately 80 kg. Furthermore, DEMO reactor requires a great deal of breeder pebbles. Therefore, the development of mass-production system for breeder pebbles is necessary. The slurry droplet wetting method was adopted in the mass-production process for Li₂TiO₃ pebbles, which had been developed in Korea. In this method, an automatic slurry dispensing system is one of the key apparatuses because the uniformity of pebbles and production rate are able to be improved. The system was successfully manufactured, which was consisted of a dispensing unit for instillation of Li₂TiO₃ slurry, a glycerin bath for hardening of droplets, and an automatic maintaining unit for constant distance between syringe needle and glycerin surface. The production rate of this system for Li₂TiO₃ pebble was estimated at 50 kg/year. In this study, it was investigated that the effect of dispensing and sintering conditions on the mass-production of Li₂TiO₃ pebbles.