Proceedings of the 22nd International Workshop on the Ceramic Breeder Blanket Interactions

Proceedings of the 22nd International Workshop on the Ceramic Breeder Blanket Interactions 6−8th October 2025 Kyoto University Uji campus, Japan Keisuke Mukai (ed.) National Institute for Fusion Science DOI: 10.5281/zenodo.17685909 https://doi.org/10.5281/zenodo.17685909 1 Contents Introduction ................................................................................................................................... 2 List of participants .......................................................................................................... 4 Photo .............................................................................................................................. 6 Program .......................................................................................................................... 8 Presentations on 6 th Oct. 2025 ..................................................................................... 16 Presentations on 7 th Oct. 2025 ................................................................................... 132 Presentations on 8 th Oct. 2025 ................................................................................... 233 Acknowledgement ...................................................................................................... 293 Workshop website: https://indico.nifs.ac.jp/e/CBBI22 DOI: 10.5281/zenodo.17685909 Published: November 24, 2025 https://doi.org/10.5281/zenodo.17685909 2 Introduction The 22 nd International Workshop on the Ceramic Breeder Blanket Interactions (CBBI-22) was held from 6th to 8th October 2025 at Obaku plaza at Kyoto University in Japan under the auspices of the IEA Implementing Agreement on the Nuclear Technology of Fusion Reactors, and in conjunction with the International Conference on Fusion Materials (ICFRM-22) held in Shizuoka, Japan. The CBBI-22 was held jointly with the 17th International Workshop on Beryllium Technology (BeWS-17), and the joint sessions took place. The workshop provided a forum for the researchers, engineers and technologists, involved in the development of the fusion ceramic breeding blanket concepts for ITER/DEMO/FPP, to exchange the latest progress in the design, fabrication, modeling, materials, isotope separation, and tritium breeding/extraction. Group photo after the CBBI/BeWS joint session on 6 th October 2025 https://doi.org/10.5281/zenodo.17685909 3 Program Advisory Board  M. Abdou (UCLA)  M-Y. Ahn (KFE)  L. V. Boccaccini (KIT)  P. Chaudhuri (IPR)  X. Chen (CAEP)  K. Feng (SWIP)  A. Ibarra(CIEMAT & IFMIF-DONES España)  Y. Kawamura (QST)  R. Knitter (KIT)  T. Terai (IAE) Local organization  Keisuke Mukai (Workshop Chair): National Institute for Fusion Science  Jae-Hwan Kim: National Institutes for Quantum Science and Technology  Juro Yagi: Kyoto University  Takumi Chikada: Shizuoka University Editor Keisuke Mukai (National Institute for Fusion Science) https://doi.org/10.5281/zenodo.17685909 4 List of participants No. Name Affiliation 1 Arturs Zarins University of Latvia, Faculty of Science and Technology, Instute of Chemical Physics 2 Asset Shaimerdenov The Instute of Nuclear Physics 3 Axel Dr. Klix Karlsruhe Instute of Technology 4 Chase Taylor Idaho Naonal Laboratory 5 Daigo Kanamori The Graduate University for Advanced Studies 6 Daniel Wilkinson University of Oxford, Materials Department 7 Dario Passafiume KIT, Instute for Applied Materials (IAM) 8 Dirk Radloff Karlsruhe Instute of Technology (KIT) 9 Donggyu Lee Seoul Naonal University 10 Harsh Patel Instute for plasma research, India 11 Hazel Gardner UKAEA 12 Hiroyasu Tanigawa Naonal Instutes for Quantum Science and Technology 13 Hitoshi Kuma Idemitsu Kosan Co., Ltd. 14 Inesh Kenzhina Satbayev University 15 Jaehwan Kim Naonal Instutes for Quantum Science and Technology 16 Julia Leys Karlsruhe Instute of Technology 17 Kazunari MEGURO Mitsui Mining & Smelng Co.,Ltd. 18 Kazuya Sasaki Hirosaki University 19 Keisuke Mukai Naonal Instute for Fusion Science 20 Kenji Morita Naonal Instutes for Quantum Science and Technology, Rokkasho Instute for Fusion Energy 21 Lee Auco UK Industrial Fusion Soluons Ltd (STEP) 22 Long Wang No.5 Huangjing Road Baijia County Shuangliu Chengdu, Sichuan 23 Magzhan Aitkulov Instute of Nuclear Physics 24 Marta Dias Instuto de Plasmas e Fusão Nuclear, Instuto Superior Técnico, Universidade de Lisboa 25 Maulik Panchal Instute for plasma research, India 26 Michael Moorehead Idaho Naonal Laboratory 27 Milan Zmitko Fusion for Energy (F4E) https://doi.org/10.5281/zenodo.17685909 5 28 Mu-Young Ahn Korea Instute of Fusion Energy 29 Oliver Leys Karlsruhe Instute of Technology 30 Pedr Charlesworth University of Oxford 31 Qilai Zhou Wuhan University of Technology 32 Regina Knier Karlsruhe Instute of Technology 33 Roman Afanasenko Karlsruhe Instute of Technology 34 ruijie zhang Department of Nuclear Engineering, Seoul Naonal University, Seoul 35 Saulet Askerbekov Instute of Nuclear Physics 36 Shumpei Iwasaki Hirosaki university 37 Shurui Shang Instute of Plasma Physics, HFIPS, Chinese Academy of Sciences, Hefei, China 38 Takayuki Terai Instute of Applied Energy 39 Xiao-Ying Yu Oak Ridge Naonal Laboratory 40 Xiaoyong Wang Southwestern Instute of Physics 41 Xinghua Wu Southwestern Instute of Physics 42 Yi-Hyun PARK Korea Instute of Fusion Energy 43 Yonghee Lee Korea Instute of Fusion Energy 44 Young Ah Park Korea Instute of Fusion Energy 45 Yuriy Ponkratov Satbayev Kazakh Naonal Research Technical University 46 Zhanar Bugybay The Instute of Nuclear Physics Number of participants at CBBI-22 from each country/region https://doi.org/10.5281/zenodo.17685909 6 Photo CBBI/BeWS joint session on 6 th October 2025 Tritium transport session on 6 th October 2025 https://doi.org/10.5281/zenodo.17685909 7 Technical tour at Heliotron-J on 8 th October 2025 Group photo after the technical tour at Heliotron-J on 8 th October 2025 https://doi.org/10.5281/zenodo.17685909 8 Program https://doi.org/10.5281/zenodo.17685909 15 https://doi.org/10.5281/zenodo.17685909 16 Presentations on 6 th Oct. 2025 https://doi.org/10.5281/zenodo.17685909 17 https://doi.org/10.5281/zenodo.17685909 18 https://doi.org/10.5281/zenodo.17685909 19 https://doi.org/10.5281/zenodo.17685909 20 https://doi.org/10.5281/zenodo.17685909 21 https://doi.org/10.5281/zenodo.17685909 22 https://doi.org/10.5281/zenodo.17685909 23 https://doi.org/10.5281/zenodo.17685909 24 https://doi.org/10.5281/zenodo.17685909 31 https://doi.org/10.5281/zenodo.17685909 32 https://doi.org/10.5281/zenodo.17685909 33 https://doi.org/10.5281/zenodo.17685909 34 https://doi.org/10.5281/zenodo.17685909 35 https://doi.org/10.5281/zenodo.17685909 36 https://doi.org/10.5281/zenodo.17685909 37 https://doi.org/10.5281/zenodo.17685909 38 https://doi.org/10.5281/zenodo.17685909 39 https://doi.org/10.5281/zenodo.17685909 40 https://doi.org/10.5281/zenodo.17685909 47 https://doi.org/10.5281/zenodo.17685909 48 https://doi.org/10.5281/zenodo.17685909 49 https://doi.org/10.5281/zenodo.17685909 50 https://doi.org/10.5281/zenodo.17685909 51 https://doi.org/10.5281/zenodo.17685909 52 https://doi.org/10.5281/zenodo.17685909 53 https://doi.org/10.5281/zenodo.17685909 54 https://doi.org/10.5281/zenodo.17685909 55 https://doi.org/10.5281/zenodo.17685909 56 https://doi.org/10.5281/zenodo.17685909 63 https://doi.org/10.5281/zenodo.17685909 64 https://doi.org/10.5281/zenodo.17685909 65 https://doi.org/10.5281/zenodo.17685909 66 https://doi.org/10.5281/zenodo.17685909 67 https://doi.org/10.5281/zenodo.17685909 68 https://doi.org/10.5281/zenodo.17685909 69 https://doi.org/10.5281/zenodo.17685909 70 https://doi.org/10.5281/zenodo.17685909 71 https://doi.org/10.5281/zenodo.17685909 72 https://doi.org/10.5281/zenodo.17685909 79 https://doi.org/10.5281/zenodo.17685909 80 https://doi.org/10.5281/zenodo.17685909 81 https://doi.org/10.5281/zenodo.17685909 82 https://doi.org/10.5281/zenodo.17685909 83 https://doi.org/10.5281/zenodo.17685909 84 https://doi.org/10.5281/zenodo.17685909 85 https://doi.org/10.5281/zenodo.17685909 86 https://doi.org/10.5281/zenodo.17685909 87 https://doi.org/10.5281/zenodo.17685909 88 A new perspective on hydrogen isotope permeation behavior of LiAlO 2 layer Long Wang, Fantao Meng, Zhihao Hong, Baoping Gong, Fengchao Zhao, Qixiang Cao Southwestern Institute of Physics, Chengdu 610225, P.R. China Formation of a LiAlO2 layer is inevitable once solid-state reaction occurred between Al2O3 tritium permeation barrier and lithium ceramics. In this study, effect of LiAlO2 layer on the hydrogen isotope permeation behavior was first investigated. LiAlO2 coating were prepared on CLF-1 steel substrates by high-temperature lithium infiltration. The formation process and hydrogen isotope permeation behavior of LiAlO2 coatings were systematically analyzed through experimental and simulation approaches. The results demonstrate that LiAlO2 exhibits inward growth over time, forming a stable LiAlO2 -Al interface after 7 days. Deuterium permeation tests revealed that the LiAlO2 coating effectively resists deuterium permeation and diffusion. Notably, as the LiAlO2 coatings thickens, both the permeability and diffusion rates decrease progressively. Computational simulations further corroborated these findings, attributing the resistance to the low H₂ adsorption energy and high dissociation barrier of the LiAlO2 surface. Keywords: LiAlO2 coating, Gas-driven permeation, Hydrogen isotope behavior https://doi.org/10.5281/zenodo.17685909 95 https://doi.org/10.5281/zenodo.17685909 96 https://doi.org/10.5281/zenodo.17685909 97 Tritium Transfer Behavior from Neutron-Irradiated LiAlO 2 to Zirconium by Heating in a Sealed Quartz Tube Hiroki Isogawaa, Kazunari Katayamaa, Rin Ganahab, Hideaki Matsuurac aDepartment of Advanced Energy Engineering Science, Kyushu University, 6-1 Kasugakouen Kasuga-shi Fukuoka, 816-0811, Japan bSchool of Engineering, Kyushu University, 744 Motooka Nishi-ku Fukuoka-shi Fukuoka, 319-0395, Japan bcDepartment of Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Motooka Nishi-ku Fukuoka-shi Fukuoka, 319-0395, Japan To ensure sufficient tritium inventory for the start-up phase of D-T fusion reactors, we have proposed a method of tritium production by the ⁶Li(n, α)T reaction in high-temperature gas-cooled reactors (HTGR). A key challenge is minimizing tritium loss under high-temperature conditions. While Li₂TiO₃ and Li₄SiO₄ are promising materials for blankets in fusion reactors, LiAlO₂—known for its excellent chemical stability at high temperatures—has been selected as a primary candidate for tritium production in HTGRs. A potential solution involves encapsulating LiAlO₂ with zirconium (Zr) in an Al₂O₃ container, but the tritium behavior in such composite systems is not yet fully understood. In this study, we investigated tritium transfer behavior from LiAlO2 to Zr under heating conditions. LiAlO2 and Ni coated Zr were sealed in a quartz tube and irradiated by neutrons in the JRR-3 reactor. After irradiation, the following 3 experiments were conducted to evaluate the extent of tritium transfer from LiAlO2 to Zr. ・Run 1: LiAlO₂ powder + Ni-coated Zr spheres, heated to effectively 700 °C ・Run 2: LiAlO₂ pebble + Ni-coated Zr spheres, heated to 900 °C ・Run 3: LiAlO₂ powder + Ni-coated Zr spheres, heated to 1000 °C The sealed samples were pre-heated to the target temperature at 30 °C/min and held for 60 minutes. In an Ar-filled glovebox, Zr spheres and LiAlO₂ were separated, and then individually reheated to either 900 °C or 1000 °C at 5 °C/min. Tritium release rates over time were quantified using sequential water bubblers: tritiated water vapor (HTO) was collected in the first bubbler, and gaseous tritium (HT), after oxidation, in the second. The tritium retention ratios in LiAlO₂, Zr, and other components were as follows: ・Run 1: LiAlO₂ powder: Ni-coated Zr : others = 94.0 : 4.3 : 1.7 ・Run 2: LiAlO₂ pebble : Ni-coated Zr : others = 89.0 : 9.9 : 1.1 ・Run 3: LiAlO₂ powder : Ni-coated Zr : others = 95.0 : 4.7 : 0.3 https://doi.org/10.5281/zenodo.17685909 98 These results indicate that more than 90% of the tritium was retained within the LiAlO₂-Zr system after heating above 700 °C. The slightly lower retention in Run 2 may be attributed to the sintering of LiAlO₂ pebbles, which likely led to crystal grain growth and reduced tritium diffusivity. The "others" category represents tritium lost via permeation through the quartz tube during pre-heating and tritium released into the Ar atmosphere during the post-heating quartz breakage process. Keywords: Tritium release, LiAlO2, Zr, neutron irradiation https://doi.org/10.5281/zenodo.17685909 99 https://doi.org/10.5281/zenodo.17685909 100 https://doi.org/10.5281/zenodo.17685909 101 https://doi.org/10.5281/zenodo.17685909 102 https://doi.org/10.5281/zenodo.17685909 103 https://doi.org/10.5281/zenodo.17685909 104 https://doi.org/10.5281/zenodo.17685909 111 https://doi.org/10.5281/zenodo.17685909 112 https://doi.org/10.5281/zenodo.17685909 113 https://doi.org/10.5281/zenodo.17685909 114 https://doi.org/10.5281/zenodo.17685909 115 https://doi.org/10.5281/zenodo.17685909 116 https://doi.org/10.5281/zenodo.17685909 117 https://doi.org/10.5281/zenodo.17685909 118 https://doi.org/10.5281/zenodo.17685909 119 https://doi.org/10.5281/zenodo.17685909 120 https://doi.org/10.5281/zenodo.17685909 127 https://doi.org/10.5281/zenodo.17685909 128 https://doi.org/10.5281/zenodo.17685909 129 https://doi.org/10.5281/zenodo.17685909 130 https://doi.org/10.5281/zenodo.17685909 131 https://doi.org/10.5281/zenodo.17685909 132 Presentations on 7 th Oct. 2025 https://doi.org/10.5281/zenodo.17685909 133 https://doi.org/10.5281/zenodo.17685909 134 https://doi.org/10.5281/zenodo.17685909 135 https://doi.org/10.5281/zenodo.17685909 136 https://doi.org/10.5281/zenodo.17685909 143 https://doi.org/10.5281/zenodo.17685909 144 ] https://doi.org/10.5281/zenodo.17685909 145 https://doi.org/10.5281/zenodo.17685909 146 https://doi.org/10.5281/zenodo.17685909 147 https://doi.org/10.5281/zenodo.17685909 148 https://doi.org/10.5281/zenodo.17685909 149 https://doi.org/10.5281/zenodo.17685909 150 https://doi.org/10.5281/zenodo.17685909 151 https://doi.org/10.5281/zenodo.17685909 152 https://doi.org/10.5281/zenodo.17685909 255 https://doi.org/10.5281/zenodo.17685909 256 https://doi.org/10.5281/zenodo.17685909 257 https://doi.org/10.5281/zenodo.17685909 258 https://doi.org/10.5281/zenodo.17685909 259 https://doi.org/10.5281/zenodo.17685909 260 https://doi.org/10.5281/zenodo.17685909 261 https://doi.org/10.5281/zenodo.17685909 262 https://doi.org/10.5281/zenodo.17685909 263 https://doi.org/10.5281/zenodo.17685909 264 https://doi.org/10.5281/zenodo.17685909 271 https://doi.org/10.5281/zenodo.17685909 272 https://doi.org/10.5281/zenodo.17685909 273 https://doi.org/10.5281/zenodo.17685909 274 https://doi.org/10.5281/zenodo.17685909 275 https://doi.org/10.5281/zenodo.17685909 276 https://doi.org/10.5281/zenodo.17685909 277 https://doi.org/10.5281/zenodo.17685909 278 https://doi.org/10.5281/zenodo.17685909 279 https://doi.org/10.5281/zenodo.17685909 280 https://doi.org/10.5281/zenodo.17685909 287 https://doi.org/10.5281/zenodo.17685909 288 https://doi.org/10.5281/zenodo.17685909 289 https://doi.org/10.5281/zenodo.17685909 290 https://doi.org/10.5281/zenodo.17685909 291 https://doi.org/10.5281/zenodo.17685909 292 https://doi.org/10.5281/zenodo.17685909 293 Acknowledgement The 22 nd International Workshop on the Ceramic Breeder Blanket Interactions (CBBI22) is co-organized and supported by the Joint Usage/Research Program on ZeroEmission Energy Research, Institute of Advanced Energy, Kyoto University (ZE2025D04). Prof. Shigeru Inagaki and Assistant Prof. Fumiyoshi Kin at Institute of Advanced Energy, Kyoto University are thanked for arranging and guiding the technical tour at Heliotron J.