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

• Published in: Journal of nuclear materials 2024-04, Vol.591, p.154905, Article 154905
• Main Authors: Kim, Jae-Hwan, Hwang, Taehyun, Sugimoto, Yutaka, Nakamichi, Masaru
• Format: Article
• Language: English
• Subjects: Be12V pebble; JA DEMO; Li2TiO3 pebble; Mixed pebbles packing; Packing fraction
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2024.154905

•JA DEMO blanket concept requires 2.0 mm-sized Be12V and 0.2 mm-sized Li2TiO3 to achieve 80 % packing fraction.•A rotating electrode process could fabricate single-sized Be12V pebbles with from 0.3 to 2.7 mm.•An emulsion process could fabricate Li2TiO3 pebbles with 0.3 mm by controlling oil viscosity and oil flow ratio.•Li2TiO3 pebbles with 0.3 mm would be adoptable by loading bigger Be12V pebbles with 2.5 mm. 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.