Fabrication of Li2TiO3 pebbles using PVA–boric acid reaction for solid breeding materials

• Li2TiO3 pebbles were successfully fabricated by the slurry droplet wetting method.
• Boron was used as hardening agent of PVA and completely removed during sintering.
• Microstructure of fabricated Li2TiO3 pebble was exceptionally homogeneous.
• Suitable process conditions for high-quality Li2TiO3 pebble were summarized.

Lithium metatitanate (Li2TiO3) is a candidate breeding material of the Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM). The breeding material is used in pebble-bed form to reduce the uncertainty of the interface thermal conductance. In this study, Li2TiO3 pebbles were successfully fabricated by the slurry droplet wetting method using the cross-linking reaction between polyvinyl alcohol (PVA) and boric acid. The effects of fabrication parameters on the shaping of Li2TiO3 green body were investigated. In addition, the basic characteristics of the sintered pebble were also evaluated. The shape of Li2TiO3 green bodies was affected by slurry viscosity, PVA content and boric acid content. The grain size and average crush load of sintered Li2TiO3 pebble were controlled by the sintering time. The boron was completely removed during the final sintering process.