Mass Transfer Behavior and Microstructure Evolution of Li4TiO4-Li2TiO3 Core-shell Breeding Ceramic Under Harsh Operating Conditions

The development of novel tritium breeding materials was urgently needed in order to continuously optimize the tritium breeding ratio (TBR) of thermonuclear fusion reactors. From this point of view, Li4TiO4-Li2TiO3 core-shell breeding materials with more reasonable structure and theoretical Li density of 0.464 g/cm3 were prepared in this work. Notably, the mass transfer experiment at 900 °C in 1% H2/Ar shows that the theoretical Li density of this core-shell material after heating for 30 days was significantly higher than that of other breeding materials, indicating that it can provide more stable and efficient TBR. Specifically, the Li mass loss of the sample after 30 days heating was 3.4%, resulting in a decrease of Li density to 0.415 g/cm3. The mechanism of Li mass loss in Li4TiO4-Li2TiO3 core-shell breeding materials was investigated in detail. Moreover, the samples did not crack or collapse during the long-term heating process, and always maintained a satisfactory crushing load, revealing that this core-shell breeding ceramic can be used for a long time under severe operating conditions.