Stereolithography and gelcasting of Li2TiO3 block breeders with a Gyroid structure: slurry optimization and performance evaluation

This study proposes porous block structures as a viable alternative to conventional pebble bed structures, aiming to overcome the structural drawbacks including low packing fractions, extensive stress concentrations, and low thermal conductivity. To validate the feasibility of the porous block structures, Gyroid Li2TiO3 block breeders were prepared by the hybrid process of stereolithography and gelcasting. The resulting Gyroid Li2TiO3 block breeders, measuring ~18.8 × 18.8 × 18.8 mm3, achieved a high packing fraction of ~78.8% through optimized slurry and sintering at 1100 °C for 3h. These Gyroid Li2TiO3 block breeders exhibited clear contours, integrated channels, a compressive strength of 8.78MPa, and a low isotropic sintering shrinkage of ~6%. The hybrid process demonstrated enormous advantages over the reported 3D printing for the preparation of porous block breeders with low shrinkage and large-sized dimensions. This study offers an effective avenue for the manufacture of porous block breeders with tunable tritium-releasing channels and large-sized configurations.