Speaker
Tsuyoshi Hoshino
(Breeding Functional Materials Development Group)
Description
Any demonstration power reactor (DEMO), which applies solid breeder blankets, requires “advanced tritium breeders” with high tritium breeding ratios and increased stability at high temperatures. However, the fabrication techniques of advanced tritium breeder pebbles have yet to be established. Therefore, the R&D on the fabrication technologies of the advanced tritium breeders and the characterization of the developed materials have been addressed in a collaborative effort between the EU and Japan (JA) in the DEMO R&D of the International Fusion Energy Research Centre (IFERC) project as a part of the Broader Approach (BA) activities from 2007 to 2016.
In the EU, two-phase materials consisting of Li4SiO4 and Li2TiO3 were developed and pebbles are produced by a novel melt-based processing. By material as well as process optimizations, the product quality as well as the yield of the process could be improved.
In the JA, Li2+xTiO3+y with Li2ZrO3 (LTZO) was developed as new ceramic composites with both high stability and high Li density. The pebbles are fabricated by an emulsion method. With respect to the tritium release characteristics of the blanket, a grain size of less than 5 μm after sintering is anticipated. Therefore, the fabrication conditions were surveyed to fabricate such pebbles.
Moreover, a number of collaborative works were performed. For instance, long-term annealing experiments of EU and JA pebbles were carried out, and the effects on the pebble quality were investigated. Also, the novel two-phase Li4SiO4 pebbles with Li2TiO3, LiAlO2 or LixLayTiO3 were fabricated by the emulsion method as promising future breeder pebbles.
This BA activity will be completed within this year, thus, we summarize the progress of R&D on advanced tritium breeders.
Co-authors
H.H. Kolb Matthias
(Institute for Applied Materials (IAM-KWT), Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany)
Regina Knitter
(Institute for Applied Materials (IAM-KWT), Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany)
Tsuyoshi Hoshino
(Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Sector of Fusion Research and Development, Japan Atomic Energy Agency, 2-166 Obuch, Omotedate, Rokkasho-mura, Kamikita-gun, Aomori, Japan)
