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Solid tritium breeding materials are used in a high temperature condition for a long time in a fusion reactor blanket. It is expected that a certain amount of Li will be evaporated and the pebble structure will be changed. Understanding of Li mass transfer behavior in the blanket is an important issue from viewpoints of establishment of tritium cycle and tritium safety. In this work the pebbles of Li2TiO3 with excess Li were heated at 900 °C in 1000 Pa H2/Ar flow for a long time (72, 240, 720, 1200 h). The amount of Li mass loss under the hydrogen atmosphere was 0.665 wt% which was less than that under the water vapor atmosphere observed in the previous study. No significant Li mass loss was observed after 240 h. By heating for 240 h, the grain diameter increased from 1.8 to 3.1 μm and the specific surface area decreased from 0.72 to 0.20 m2/g. After 240 h, no significant grain growth and no significant decrease in the specific surface area were observed. From these results, it seems that there is a relation between Li mass loss and grain growth.

In a solid breeding blanket, ceramic breeder pebbles are in contact with reduced activation ferritic martensitic (RAFM) steel at high temperatures for years and accordingly form a corrosion layer on the blanket structural steel. Present study focuses on corrosion characteristics of EUROFER97 RAFM steel by an advanced breeder material of Li2TiO3 with excess Li (initial ratio of Li/Ti = 2.2) at 623, 823, and 1073 K under sweep gas (He + 0.1% H2) flow. Formation of a thick oxide double layer was found on the surface of the EUROFER plates heated at 823 and 1073 K, while the corrosion layer formed at 673 K was

Lithium titanate with excess lithium (Li2+xTiO3+y) is one of the most promising candidates among advanced tritium breeders for demonstration power plant reactors because of its good tritium release characteristics. However, the tritium breeding ratio (TBR) of Li2+xTiO3+y is smaller than that of e.g., Li2O or Li8TiO6 because of its lower Li density. Therefore, new Li-containing ceramic composites with both high stability and high Li density have been developed. Thus, this study focused on the development of a solid solution with a new characteristic. The solid-solution pebbles of Li2+xTiO3+y with Li2ZrO3 (Li2+x(Ti,Zr)O3+y), designated as LTZO, were fabricated by an emulsion method. The X-ray diffraction patterns of sintered LTZO pebbles are approximately the same as those of Li2+xTiO3+y pebbles, and no peaks attributable to Li2ZrO3 are observed. These results demonstrate that LTZO pebbles are not a two-phase material but rather a solid solution. Furthermore, LTZO pebbles were easily sintered under air. Thus, the LTZO solid solution is a candidate breeder material for super advanced (SA) tritium breeders.