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Horiguchi, Naoki; Yoshida, Hiroyuki; Kitatsuji, Yoshihiro; Hasegawa, Makoto*; Kishimoto, Tadafumi*
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 7 Pages, 2023/05
From the viewpoint of energy security in Japan and reduction of the environmental load, continuous operation of light water reactors is essential. Since a pH adjuster with enriched Li-7 ions is required for water quality control on PWR, the development of Li-7 enrichment technology is one of the key issues. The multi-channel counter-current electrophoresis (MCCCE) method has been developed as the technology with a low environmental load. To put this method into practical use, it is necessary to understand Li-7 ion behavior in the channel flow and optimize the experimental condition to separate Li-7 and its isotope. In this paper, to understand Li-7 ion behavior in a single channel of the experimental apparatus, a numerical simulation method based on a computational fluid dynamics (CFD) code with a particle tracking method, TPFIT-LPT, was developed. In the method, the motion of multiple ions under the electric field was simulated as a particle with an added velocity by the electric field. The difference in the isotopes was represented by changing of the magnitude of the added velocity. We also considered that although it is impossible to measure the behavior of each ion, it is important to measure the flow velocity of the bulk fluid for the validation of the numerical simulation. We developed a lab-scale experimental apparatus in which the single channel of the actual apparatus was simplified to measure the flow velocity by Particle Image Velocimetry (PIV). We set a pulsation flow condition on the lab-scale experiment, which is one of difficult conditions for the numerical simulation, and measured the velocity. As the result, we confirmed that the pulsation flow was reproduced. We set the measured data as the inlet boundary condition of the numerical simulation and conducted it. As the numerical result, we confirmed the ions affected by the electric field moved upstream with pulsation. We also confirmed the effect of the electric field on the motion of the isotope.
Amekura, Hiroshi*; Ishikawa, Norito; Okubo, Nariaki; Ridgway, M.*; Giulian, R.*; Mitsuishi, Kazuki*; Nakayama, Yoshiko*; Buchal, C.*; Mantl, S.*; Kishimoto, Naoki*
Physical Review B, 83(20), p.205401_1 - 205401_10, 2011/05
Times Cited Count：35 Percentile：78.45(Materials Science, Multidisciplinary)Elongation of metal nanoparticles (NPs) embedded in silica induced by swift heavy-ion irradiation, from spheres to spheroids, has been evaluated at low fluences by linearly polarized optical absorption spectroscopy. It is important to clarify whether the high fluences, i.e., track overlaps, are essential for the elongation. Zn NPs embedded in silica were irradiated with 200-MeV Xe ions. The comparison with numerical simulation suggested that the elongation of Zn NPs was induced by nonoverlapping ion tracks.
Suzuki, Motofumi*; Takahashi, Michiko*; Tsukamoto, Takashi*; Watanabe, Satoshi; Matsuhashi, Shimpei; Yazaki, Junshi*; Kishimoto, Naoki*; Kikuchi, Shoshi*; Nakanishi, Hiromi*; Mori, Satoshi*; et al.
Plant Journal, 48(1), p.85 - 97, 2006/10
Times Cited Count：172 Percentile：95.77(Plant Sciences)
ionsLee, C. G.; Omura, Takahito*; Takeda, Yoshihiko*; Matsuoka, Saburo*; Kishimoto, Naoki*
Journal of Nuclear Materials, 326(2-3), p.211 - 216, 2004/03
Times Cited Count：4 Percentile：29.26(Materials Science, Multidisciplinary)Magnesium aluminate spinel of single crystal was irradiated with 60 keV Cu at a dose rate up to 100 
A/cm
, to a total dose of 3
10
ions/cm, in order to study changes in hardness and step-height swelling by high-flux implantation. Hardness determined by nano-indentation measurements steeply decreased with implantation. There is a strong negative correlation between dose-rate dependences of the hardness and the step-height swelling: the former decreases as the latter increases. The Rutherford Backscattering Spectrometry (RBS)/channeling measurements showed that the spinel is not completely amorphized over the dose-rate range in this study, and the radiation-induced softening observed is not due to amorphization. Results of optical absorbance suggested that radiation-induced point defects and their clusters on the anion sublattices of the spinel played an important role in the radiation-induced swelling under high-flux ion implantation.
Horiguchi, Naoki; Yoshida, Hiroyuki; Kitatsuji, Yoshihiro; Fukumori, Mai*; Takemura, Yuki*; Hasegawa, Makoto*; Kishimoto, Tadafumi*
no journal, ,
no abstracts in English
Horiguchi, Naoki; Yoshida, Hiroyuki; Kitatsuji, Yoshihiro; Fukumori, Mai*; Hasegawa, Makoto*; Kishimoto, Tadafumi*
no journal, ,
A Li-7 enriched pH adjuster is essential for water quality control on PWRs. As the required Li-7 enrichment technology, we have developed the multi-channel counter-current electrophoresis (MCCCE) method. In this research, to understand the behavior of ions in the enrichment experiment, we developed a numerical simulation method of the long-time behavior of the ions based on the 3-dimensional field data of the electricity by commercial software and the flow by TPFIT-LPT. In this work, we applied it to the behavior of the ions in a simplified plate-type flow channel from the experimental one. Since the separation coefficient calculated from the simulation results of Li-7 and Li-6 ions agreed well with the experimental value, we confirmed the applicability of the method.
