Optimization of sintering conditions of advanced tritium breeder pebbles fabricated by the emulsion method

Hoshino, Tsuyoshi

Fusion Engineering and Design, 98-99, p.1788 - 1791, 2015/10

https://doi.org/10.1016/j.fusengdes.2015.04.023

Demonstration power reactors require advanced tritium breeders that have high stability at high temperatures. Therefore, an original material of LiTiO with excess Li (LiTiO) as an advanced tritium breeder that can make up to the lithium loss has been proposed. Furthermore, The author has been developing a technique of fabricating LiTiO pebbles using the emulsion method. Considering the tritium release characteristics and the packing factor of the blanket, the desired pebble diameter and grain size after sintering were 1 mm and 5 m, respectively. To prevent the grain growth of pebbles, calcined LiTiO pebbles were sintered in a vacuum atmosphere at 1073 K for 3 h and in a 1%H-He atmoshere at 1323K for 5 h. The average grain size on the surfaces and cross sections of the sintered LiTiO pebbles was 5 m. In addition, the diameter of sintered LiTiO pebbles was 1.07 mm.

Evaluation of tritium release properties of advanced tritium breeders

Hoshino, Tsuyoshi; Ochiai, Kentaro; Edao, Yuki; Kawamura, Yoshinori

Fusion Science and Technology, 67(2), p.386 - 389, 2015/03

https://doi.org/10.13182/FST14-T35

Demonstration power reactors (DEMOs) require advanced tritium breeders that have high stability at high temperatures. Therefore, the pebble fabrication of LiTiO with excess Li (LiTiO) as an advanced tritium breeder was carried out. In this study, a preliminary examination of the tritium release properties of advanced tritium breeders was performed. DT neutron irradiation experiments were performed at the fusion neutronics source (FNS) facility in JAEA. The LiTiO pebbles exhibited good tritium release properties similar to the LiTiO pebbles. In particular, the released amount of HT gas for easier tritium handling was higher than that of HTO water.

Trial examination of direct pebble fabrication for advanced tritium breeders by the emulsion method

Hoshino, Tsuyoshi

Fusion Engineering and Design, 89(7-8), p.1431 - 1435, 2014/10

https://doi.org/10.1016/j.fusengdes.2013.12.052

Demonstration power reactors (DEMOs) require advanced tritium breeders with high thermal stability. For the mass production of advanced tritium breeder pebbles, pebble fabrication by the emulsion method is a promising technique. To develop the most efficient pebble fabrication method, a new direct pebble fabrication process utilizing the emulsion method was implemented. A prior pebble fabrication process consisted of the preparation of raw materials followed by granulation. The new process integrates the preparation and granulation of raw materials. The slurry for the emulsion granulation of LiTiO as a tritium breeder consists of mixtures of LiCO and TiO at specific ratios. The average diameter of the obtained sintered LiTiO pebbles were 1.0 mm. The trial fabrication results suggest that the new process has the potential to increase the fabrication efficiency of advanced tritium breeder pebbles.

Dynamics of edge limit cycle oscillation in the JFT-2M tokamak

Kobayashi, Tatsuya*; Ito, Kimitaka*; Ido, Takeshi*; Kamiya, Kensaku; Ito, Sanae*; Miura, Yukitoshi; Nagashima, Yoshihiko*; Fujisawa, Akihide*; Inagaki, Shigeru*; Ida, Katsumi*; et al.

Nuclear Fusion, 54(7), p.073017_1 - 073017_14, 2014/07

https://doi.org/10.1088/0029-5515/54/7/073017

In the JFT-2M tokamak, limit-cycle oscillation among several variables is observed before L-to-H transition. Spatiotemporal dynamics of the LCO is analyzed in detail. Zonal fows are not seen, and modulation in edge-localized poloidal flow and density gradient is observed. Modulation is also seen in Reynolds stress, caused by that in turbulence intensity and turbulence wavenumber. However, flow acceleration is not able to be explained by the modulation in the Reynolds stress. Rapid inward propagation in density gradient and turbulence packet is also observed. Characteristics of the propagation are veried by means of turbulence spreading theory and diffusion theory.

Development of methods for reprocessing and reuse of tritium breeder materials in broader approach activities

Hoshino, Tsuyoshi

Journal of Nuclear Materials, 442(1-3), p.S425 - S428, 2013/11

https://doi.org/10.1016/j.jnucmat.2013.03.009

Development of reprocessing and reuse of this spent breeder including unburned Li is important from viewpoint of effective utilization Li as a limited resource. This activity has been started between Japan and the EU in the Broader Approach activities. The effect of solvent on dissolution of LiTiO powder was evaluated. LiTiO powder with 99.9% purity was prepared as a starting powder. Solubility of Li was evaluated from the measurement result of the Li content in solution by ICP (inductively coupled plasma) atomic emission spectrometry. Peroxide hydrogen (HO) was selected as solvent. Most of LiTiO was soluble in room temperature, and then the solubility of Li were larger than 90%.

Trial synthesis of LiBeO for high-functional tritium breeders

Hoshino, Tsuyoshi; Oikawa, Fumiaki; Natori, Yuri*; Kato, Kenichi*; Sakka, Tomoko*; Nakamura, Mutsumi*; Tatenuma, Katsuyoshi*

Fusion Engineering and Design, 88(9-10), p.2268 - 2271, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.05.013

Lithium titanate with additional Li (LiTiO) and lithium orthosilicate (LiSiO) is one of the most promising candidates for use in a tritium breeder because of its good chemical and mechanical stabilities. Currently, mixtures of tritium breeder pebble and neutron multiplier (Be or BeTi) pebble are being considered for use in increasing the tritium breeding ratio in a breeding blanket. However, lithium and beryllium are gradually reacted under practical operating conditions, and therefore a high-functional tritium breeder such as lithium beryllium oxide (LiBeO) needs to be developed to compensate for this reactive characteristic under high temperature use. In this study, methods of synthesizing LiBeO have been extensively investigated by means of solid-phase reaction. The solid-phase reaction of LiOH(HO) and BeO is a suitable synthesis method for lithium beryllium oxide (LiBeO). It is expected that single-phase LiBeO will be stable under the mixture conditions of a tritium breeder and neutron multiplier in the blanket region at high temperatures.

Preliminary studies of lithium recovery technology from seawater by electrodialysis using ionic liquid membrane

Hoshino, Tsuyoshi

Desalination, 317, p.11 - 16, 2013/05

https://doi.org/10.1016/j.desal.2013.02.014

Lithium (Li), one of the 31 rare metal elements among the 112 known elements, is fast becoming a valuable commodity. As a means of addressing global warming, the world is increasingly turning to the use of Li-ion batteries in electric vehicles and as storage batteries in the home; therefore, there is a growing need for Li. Li is primarily recovered from salt lakes in South America but is also present in seawater. Thus, I propose a new method for recovering Li from seawater by electrodialysis, wherein Li selectively permeates from the anode side to the cathode side through an ionic liquid. Hoshino developed a novel Li-isotope separation technique that uses an ionic liquid. This technique could also be used to recover Li from seawater. Measurements of the ion concentration at the cathode side as a function of dialysis duration showed that the Li concentration increased to 5.94% after 2 h with an applied electric voltage of 2 V. Moreover, the other ions in the seawater did not permeate an ionic liquid. With both ends of an ionic liquid covered with a MEA (Membrane Electrode Assembly) to prevent outflow of the ionic liquid, the Li concentration increased. This new recovery method shows good energy efficiency and is easily scalable and thus is suitable for use in seawater desalination plants.

Characteristic of tritium release from LiTiO under D-T neutron irradiation

Edao, Yuki; Kawamura, Yoshinori; Ochiai, Kentaro; Hoshino, Tsuyoshi; Takakura, Kosuke; Ota, Masayuki; Iwai, Yasunori; Yamanishi, Toshihiko; Konno, Chikara

JAEA-Research 2012-040, 15 Pages, 2013/02

JAEA-Research-2012-040.pdf:1.8MB

Tritium generation and recovery studies on LiTiO as a solid breeding material under neutron irradiation carried out in the Fusion Neutron Source (FNS) facility. A capsule with LiTiO packed bed was put in a system which simulated an actual blanket system which built in beryllium blocks and lithium titanate ones. Estimated values of the amount of tritium generation by a numerical calculation agreed closely with experimental values. The capsule was heated up to 300C, and helium, helium with water vapor, hydrogen or hydrogen/water vapor were selected as purge gas. In the case of purge by helium added water vapor, the ratio of HTO to total tritium release was 98%. In helium with hydrogen/water vapor purge, the ratio of HTO to total tritium release was 80%, which was confirmed that HTO released by isotope exchange reaction between water vapor and tritium. In helium with hydrogen purge, the ratio of HT to total tritium release was 6070%, which was shown that HT released by isotope exchange reaction between hydrogen gas and tritium. HTO released by water generation reaction between hydrogen in purge gas and oxygen in LiTiO although water vapor was not added in purge gas. The ratio of HTO release seemed to be small under the deoxidized condition of the LiTiO surface. Tritium release behavior in the LiTiO depended on the composition of purge gas, and its chemical form was affected by the surface conditions of LiTiO.

Development of the water cooled ceramic breeder test blanket module in Japan

Enoeda, Mikio; Tanigawa, Hisashi; Hirose, Takanori; Suzuki, Satoshi; Ochiai, Kentaro; Konno, Chikara; Kawamura, Yoshinori; Yamanishi, Toshihiko; Hoshino, Tsuyoshi; Nakamichi, Masaru; et al.

Fusion Engineering and Design, 87(7-8), p.1363 - 1369, 2012/08

https://doi.org/10.1016/j.fusengdes.2012.03.007

The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. For the TBM testing and evaluation toward DEMO blanket, the module fabrication technology development by a candidate structural material, reduced activation martensitic/ferritic steel, F82H, is one of the most critical items from the viewpoint of realization of TBM testing in ITER. Fabrication of a real scale first wall, side walls, a breeder pebble bed box and assembling of the first wall and side walls have succeeded. Recently, the real scale partial mockup of the back wall was fabricated. The fabrication procedure of the back wall, whose thickness is up to 90 mm, was confirmed toward the fabrication of the real scale back wall by F82H. This paper overviews the recent achievements of the development of the WCCB TBM in Japan.

Japanese contribution to the DEMO-R&D program under the Broader Approach activities

Nishitani, Takeo; Yamanishi, Toshihiko; Tanigawa, Hiroyasu; Nozawa, Takashi; Nakamichi, Masaru; Hoshino, Tsuyoshi; Koyama, Akira*; Kimura, Akihiko*; Hinoki, Tatsuya*; Shikama, Tatsuo*

Fusion Engineering and Design, 86(12), p.2924 - 2927, 2011/12

https://doi.org/10.1016/j.fusengdes.2011.07.004

Several technical R&D activities related to the blanket materials are newly launched as a part of the Broader Approach (BA) activities, which was initiated by the EU and Japan. According to the common interests of these parties for DEMO, R&Ds on reduced activation ferritic/martensitic (RAFM) steels as structural material, SiCf/SiC composites as a flow channel insert material and/or alternative structural material, advanced tritium breeders and neutron multipliers, and tritium technology are carried out through the BA DEMO R&D program, in order to establish the technical bases on the blanket materials and the tritium technology required for DEMO design. This paper describes overall schedule of those R&D activities and recent progress in Japan carried out by JAEA as the domestic implementing agency on BA, collaborating with Japanese universities and other research institutes.