Local and electronic structures of BaTiO/KNbO nanocomposite particles

Yoneda, Yasuhiro; Kobayashi, Toru; Tsuji, Takuya; Shibata, Goro; Takeda, Yukiharu*; Saito, Yuji; Khanal, G. P.*; Fujii, Ichiro*; Ueno, Shintaro*; Sato, Yukio*; et al.

Japanese Journal of Applied Physics, 64(8), p.08SP07_1 - 08SP07_8, 2025/08

https://doi.org/10.35848/1347-4065/adf4f1

It has become possible to synthesize high-quality composite nanoparticles in which a different material is grown on the surface of nanoparticle crystals. To evaluate such nanostructures, it is effective to combine different evaluation methods at various scales. We performed various structural and electronic state evaluations of BaTiO/KNbO nanocomposite particles using synchrotron radiation. From the structural evaluation, it was confirmed that the nanocomposite particles have a core of 100 nm of BaTiO covered with 20 nm of KNbO. The O-K absorption edge spectrum of the outermost surface KNbO was different from that of the bulk and nanoparticles, and it was found that the chemical bonding state changes when KNbO is made into composite particles.

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2023

Kokubun, Yuji; Hosomi, Kenji; Seya, Natsumi; Nagaoka, Mika; Inoue, Kazumi; Koike, Yuko; Hasegawa, Ryo; Kubota, Tomohiro; Hirao, Moe; Iizawa, Shogo; et al.

JAEA-Review 2024-053, 116 Pages, 2025/03

JAEA-Review-2024-053.pdf:3.26MB

Based on the regulations (the safety regulation of Tokai Reprocessing Plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution prevention act, and by law of Ibaraki Prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2023. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

Large-eddy simulation analysis on the area of influence of local hilly terrains on plume dispersion released from a stack

Sato, Takuto; Goger, B.*; Nakayama, Hiromasa

SOLA (Scientific Online Letters on the Atmosphere) (Internet), 21, p.17 - 23, 2025/01

https://doi.org/10.2151/sola.2025-003

In this study, we conducted large-eddy simulations of turbulent flows and plume dispersion over idealized two-dimensional double steep hills. In the simulations, we investigated the distribution patterns of the mean plume concentrations, considering various distances between the hills and emission sources. Our objective was to provide information on the area of influence of local hilly terrains on plume dispersion from the viewpoint of accuracy, i.e., determining if the conventional Gaussian plume model can accurately predict plume concentrations. The result showed that the clockwise circulation was dominant in the area between the windward and leeward hills (valley) when the valley width was less than 10 times the hill height (). This circulation makes the flow close to the stack remain in the valley, resulting in the higher concentrations in the valley than in wider-valley ( 10 valley) cases. The effect of the leeward hill on the flow field was negligible when the valley width was greater than 10. In the area beyond 20 from the crest of the windward hill, estimated plume spreads for all cases were similar, indicating that the area of influence of the hills was approximately 20.

Analysis work on flush-out of plutonium and uranium for decommissioning of main plant in Tokai Reprocessing Plant

Sato, Hinata; Mori, Amami; Kuno, Sorato; Horigome, Kazushi; Goto, Yuichi; Yamamoto, Masahiko; Taguchi, Shigeo

JAEA-Technology 2024-011, 56 Pages, 2024/10

JAEA-Technology-2024-011.pdf:2.5MB

Flush-out, which recovers remaining nuclear materials in the process and transfer it to a highly radioactive liquid waste storage tank, has been performed at main plant of Tokai Reprocessing Plant. The flush-out has been composed from three steps: first step is to remove of spent fuel sheared powder, second step is to collect plutonium solution stored in the process, and third step is to convert uranium solution into uranium trioxide powder. The first step of flush-out activity has been completed in 2022. Second and third steps of flush-out have been completed from March 2023 to February 2024. Process control analysis has been performed for operation of the facility, and material accountancy analysis has been performed to control the accountancy of nuclear materials. In addition, related analytical work such as pretreatment for transporting inspection samples for safeguards analysis laboratories in IAEA has been also performed. This report describes results of analytical work performed in collections of plutonium and uranium solutions in second and third steps of the flush-out, including calibration of analytical equipment, waste generation, and education and training of analytical operator.

Single-shot laser-driven neutron resonance spectroscopy for temperature profiling

Lan, Z.*; Arikawa, Yasunobu*; Mirfayzi, S. R.*; Morace, A.*; Hayakawa, Takehito*; Sato, Hirotaka*; Kamiyama, Takashi*; Wei, T.*; Tatsumi, Yuta*; Koizumi, Mitsuo; et al.

Nature Communications (Internet), 15, p.5365_1 - 5365_7, 2024/07

https://doi.org/10.1038/s41467-024-49142-y

Existence of local polar domains in perovskite oxyfluoride, BaFeOF

Katsumata, Tetsuhiro*; Suzuki, Ryo*; Sato, Naoto*; Oda, Ryoya*; Motoyama, Shingo*; Suzuki, Shumpei*; Nakashima, Mamoru*; Inaguma, Yoshiyuki*; Mori, Daisuke*; Aimi, Akihisa*; et al.

Chemistry of Materials, 36(8), p.3697 - 3704, 2024/04

https://doi.org/10.1021/acs.chemmater.3c03275

A perovskite-type oxynitride BaFeOF was prepared by high-pressure synthesis. Since the SHG signal was observed in the obtained material, suggesting the existence of spontaneous polarization, the mechanism of polarization was investigated by synchrotron high-energy X-ray diffraction. The obtained pair distribution functions were fitted, and a local polarization mechanism with different orientations was found. Since BaFeOF is also a magnetic material, a magnetic domain and a ferroelectric domain are considered to coexist.

ICRU Report 98, Stochastic nature of radiation interactions; Microdosimetry

Braby, L. A.*; Conte, V.*; Dingfelder, M.*; Goodhead, D. T.*; Pinsky, L. S.*; Rosenfeld, A. B.*; Sato, Tatsuhiko; Waker, A. J.*; Guatelli, S.*; Magrin, G.*; et al.

Journal of ICRU, 23(1), p.1 - 168, 2023/12

https://doi.org/10.1177/14736691231211380

This report provides a comprehensive description of the basic concepts and theories, computational and experimental procedures, and applications of microdosimetry.

Analysis work report on removal of spent fuel sheared powder for decommissioning of main plant

Aoya, Juri; Mori, Amami; Sato, Hinata; Kono, Soma; Morokado, Shiori; Horigome, Kazushi; Goto, Yuichi; Yamamoto, Masahiko; Taguchi, Shigeo

JAEA-Technology 2023-008, 34 Pages, 2023/06

JAEA-Technology-2023-008.pdf:1.92MB

Flush-out, by which nuclear materials in the Tokai Reprocessing Plant process are recovered, has been started in June 2022 as the first step of decommissioning. Flush-out consists of removal of spent fuel sheared powder, plutonium solution, uranium solution, and the other nuclear materials. Removal of spent fuel sheared powder has been completed in September 2022. During removal of spent fuel sheared powder, uranium concentration, plutonium concentration, acid concentration, radioactivity concentration, and solution density have been analyzed for process control. For nuclear material accountancy, uranium concentration, plutonium concentration, isotope ratio, and solution density have been analyzed. Analysis work including sample pretreatment before transportation to IAEA analytical facility for safeguards, and the other operations related to Flush-out such as calibration of analytical instruments, education, and training of operators are reported.

Americium(III)/curium(III) complete separation and sensitive fluorescence detection by capillary and gel electrophoresis using emissive hexadentate/octadentate polyaminocarboxylate ligands

Saito, Shingo*; Haraga, Tomoko; Marumo, Kazuki*; Sato, Yoshiyuki; Nakano, Yuta*; Tasaki-Handa, Yuiko*; Shibukawa, Masami*

Bulletin of the Chemical Society of Japan, 96(3), p.223 - 225, 2023/03

https://doi.org/10.1246/bcsj.20220346

Highly efficient and effective separation between americium (Am) and curium ion (Cm) was achieved by two simple electrophoresis-based techniques. Am and Cm ions were complexed with fluorophore-modified acyclic hexadentate and octadentate polyaminocarboxylates and then were electrophoretically separated and fluorescently detected in free solution with ternary complexation or in gel medium.

Strangeness physics programs by S-2S at J-PARC

Gogami, Toshiyuki*; Ebata, Kengo; Fujita, Manami; Harada, Takeshi; Hasegawa, Shoichi; Hosomi, Kenji; Ichikawa, Yudai; Imai, Kenichi*; Kim, S.; Nanamura, Takuya; et al.

EPJ Web of Conferences, 271, p.11002_1 - 11002_7, 2022/11

https://doi.org/10.1051/epjconf/202227111002