Current progress on fabrication processes of breeding functional materials for JA DEMO fusion applications

Abstract

A JA DEMO blanket requires Be12V pebbles with 2 mm (or bigger) and Li2TiO3 with 0.2 mm as a mixed pebbles packing concept for achieving an 80 % packing fraction. The authors' group has achieved a significant milestone by successfully manufacturing Be12V pebbles through a pioneering rotating electrode process, marking a world-first achievement. Simultaneously, Li2TiO3 pebbles have been produced utilizing an emulsion process developed by the same research group. It is worth noting that most prior studies focused on pebbles with a 1 mm diameter, as this size was initially recommended for the ITER TBM before the introduction of the new packing concept. The rotating electrode process has successfully yielded Be12V pebbles measuring 2.5 mm or larger, and their characteristics have been thoroughly examined, offering a comprehensive overview of the current progress in Be12V pebble production. Furthermore, to meet the specific requirements of the JA DEMO blanket, experiments were conducted to fabricate smaller Li2TiO3 pebbles. It was discovered that Li2TiO3 pebbles with 0.3 mm could be successfully produced by adjusting the oil viscosity and flow ratio within the existing emulsion process system.