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Prihutami, P.*; Toda, Kanako*; Chaerun, R. I.; Oya, Yusuke*; Kikuchi, Ryosuke*; Otake, Tsubasa*; Sato, Tsutomu*; Saito, Takumi*
Applied Clay Science, 292, p.108330_1 - 108330_9, 2026/11
Times Cited Count：0Limited understanding of zinc (Zn) immobilization in altered geopolymers limits prediction of waste-form durability. This study examined the local structure and retention mechanism of Zn in a metakaolin-based potassium geopolymer by X-ray absorption spectroscopy (XAS). Zn-bearing samples were prepared from metakaolin, zinc chloride (ZnCl
) solution, potassium silicate, and potassium hydroxide, cured at 40
C and 25C for 48 h, and leached in deionized water for up to 90 days. Zn release was only 0.14%, with limited Al, Si, and Cl release. The main geopolymer framework was preserved after leaching. XAS showed that Zn was initially tetrahedrally coordinated with oxygen and linked to Si or Al tetrahedra. After leaching, Zn changed to octahedral coordination and formed a brucite-like Al-bearing co-precipitate, indicating strong Zn retention despite local structural alteration.
-curing condition on phase assemblage and mechanical response of C
S pastes; Insights from atomic, crystallographic, and macroscopic deformationsCho, S.*; Im, S.*; Tominaga, Aki; Shobu, Takahisa; Bae, S.*; 5 of others*
Journal of Building Engineering, 128, p.116694_1 - 116694_31, 2026/06
Times Cited Count：0
-ray beam measurementsOmer, M.; Shizuma, Toshiyuki*; Koizumi, Mitsuo; Taira, Yoshitaka*; Zen, H.*; Ogaki, Hideaki*; Hajima, Ryoichi*
Radiation Physics and Chemistry, 240, p.113467_1 - 113467_8, 2026/03
Times Cited Count：1 Percentile：46.18(Chemistry, Physical)Makarov, S. S.*; Zhakhovsky, V. V.*; Grigoryev, S. Yu.*; Chuprov, P.*; Pikuz, T. A.*; Inogamov, N. A.*; Khokhlov, V. A.*; Petrov, Y. V.*; Perov, E. A.*; Shepelev, V.*; et al.
Nature Communications (Internet), 16, p.11504_1 - 11504_13, 2025/12
Times Cited Count：1 Percentile：0.00(Multidisciplinary Sciences)Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*
JAEA-Review 2025-011, 74 Pages, 2025/08
JAEA-Review-2025-011.pdf:5.31MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science &Z Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2023. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2021, this report summarizes the research results of the "Development of a cooperative operation robot system for radiation source exploration" conducted from FY2021 to FY2023. The present study aims to develop a robot system (CORRASE: Cooperative Operation Robot system for RAdiation Source Exploration), realizing radiation source exploration with wide field of view, rapidity, and low cost. In FY2023, our research efforts focused on verification tests for radiation source exploration by summarizing the results of our previous studies. Polyhedral type gamma-ray directional detectors were fabricated from 8 BGO scintillators and shielding bodies. Radiation source exploration experiments were performed by developing a cooperative operation robot system consisting of 3 multi-legged robots carrying the gamma-ray detectors, IMUs (Inertial Measurement Units), and LiDARs (Light Detection And Ranging). An unknown test environment for the radiation source exploration was constructed by placing obstacles and a 10 MBq 
Cs sealed source as a simulated radioactive contamination source in a room measuring 7.8 
5.3 m
. The developed system was used to create the environmental map, to formulate the exploration plan, to create the heatmap of the radiation counts, and to image the radiation source from the calculated optimal observation position. The localization of the simulated radioactive contamination source was successfully performed with the cooperation of the 3 robot systems by displaying the image of the radiation source fused on the environmental map. It can be concluded that the initial goal of this study has been successfully achieved by developing the robot system realizing radiation source exploration.
Ohashi, Tomonori*; Sakamaki, Tatsuya*; Funakoshi, Kenichi*; Steinle-Neumann, G.*; Hattori, Takanori; Yuan, L.*; Suzuki, Akio*
Journal of Mineralogical and Petrological Sciences (Internet), 120(1), p.240926a_1 - 240926a_13, 2025/06
Times Cited Count：1 Percentile：36.35(Mineralogy)We explore the structures of dry and hydrated (HO and DO) Na
Si
O
melt at 0-6 GPa and 1000-1300 K and glasses recovered from high pressure and temperatures by in-situ neutron and X-ray diffraction. The structures of the melts at 0-10 GPa and 3000 K are also investigated by ab-initio molecular dynamics simulation. In-situ neutron experiments revealed that the D-O distance increases with compression due to the formation of -O-D-O- bridging species, which is reproduced by the molecular dynamics simulations. The pressure-induced -O-D-O- formation reflects a more rigid incorporation of hydrogen, which acts as a mechanism for the experimentally observed higher solubility of water in silicate melts. Together with shrinking modifier domains, this process dominates the compression behavior of hydrous NaSiO melt, whereas the compression of dry NaSiO at 0-10 GPa and 3000 K is governed largely by bending of the Si-O-Si angle. The molecular dynamics simulations on hydrous NaSiO melts further suggest that the sodium ions are scavenged from its network-modifying role via 2(![$$^{[4]}$$](/search/images/ERPHWWZULV4SI.gif)
Si-O
+ Na
) 
Si-(O-![$$^{[5]}$$](/search/images/ERPHWWZVLV4SI.gif)
Si-O)
+ 2Na and Si-O + Na + Si-OH Si-(O-H-O-Si) + Na with increasing pressure.
Suzuki, Kenji*; Miura, Yasufumi*; Toyokawa, Hidenori*; Shiro, Ayumi*; Shobu, Takahisa; Morooka, Satoshi; Shibayama, Yuki
Quantum Beam Science (Internet), 9(2), p.15_1 - 15_15, 2025/06
Tomota, Yo*; Harjo, S.; Xu, P. G.; Morooka, Satoshi; Gong, W.; Wang, Y.*
Metals, 15(6), p.610_1 - 610_19, 2025/05
Times Cited Count：4 Percentile：35.62(Materials Science, Multidisciplinary)
phases in undoped and Ca-modified sodium niobatesAso, Seiyu*; Matsuo, Hiroki*; Yoneda, Yasuhiro; Morikawa, Daisuke*; Tsuda, Kenji*; Oyama, Kenji*; Ishigaki, Toru*; Noguchi, Yuji*
Physical Review B, 111(17), p.174114_1 - 174114_12, 2025/05
Times Cited Count：2 Percentile：49.43(Materials Science, Multidisciplinary)We investigate the crystal structures, phase transitions, and phase stability of undoped and Ca-modified NaNbO through a combined analysis of high-resolution synchrotron radiation X-ray and neutron diffraction, convergent-beam electron diffraction, and density functional theory (DFT) calculations. It is demonstrated that the antiferroelectric (AFE)- phase is stabilized over a wide temperature range of 200 to 800 K by Ca modification, and that the NaNbO
is stabilized by temperature-driven isostatic pressure accompanied by lattice expansion, whereas the Ca-modified NaNbO is induced by composition-induced chemical pressure along with lattice shrinkage.
under hydrostatic pressure; A Combined neutron, X-ray, Raman, and first-principles calculation studyEfthimiopoulos, I.*; Klotz, S.*; Kunc, K.*; Baptiste, B.*; Chauvigne, P.*; Hattori, Takanori
Physical Review B, 111(13), p.134103_1 - 134103_13, 2025/04
Times Cited Count：1 Percentile：28.15(Materials Science, Multidisciplinary)We present a comprehensive study of the high pressure behaviour of ReO using X-ray and neutron diffraction, Raman scattering and first-principles calculations to 15 GPa. We show that the ambient pressure 
structure converts at 0.7 GPa in a continuous phase transition directly to a cubic phase with space group 
and rhombohedral 
structures in this pressure range are an artifact due to an alteration of the sample by high-flux synchrotron X-ray radiation. The structural pressure dependence of the 
O samples are presented. The data shed light onto the unusual transition and densification mechanism due to progressive tilting of essentially rigid ReO octahedra.
Hizukuri, Kyoko*; Fujibuchi, Toshio*; Han, D.*; Arakawa, Hiroyuki*; Furuta, Takuya
Radiological Physics and Technology, 18(1), p.196 - 208, 2025/03
One of the radiation protection measures for medical personnel engaged in X-ray fluoroscopy is the use of radiation-protective plates and a simulation tool to evaluate effect of the plates is desired. Monte Carlo simulation has an advantage of being able to accurately calculate the interaction between radiations and various objects present in the X-ray room. However, Monte Carlo simulation has a disadvantage of being computationally time-consuming. Therefore, we developed a new simplified method to calculate the dose distribution in a short time with the presence of protective plates using pre-computed directional vectors (SCV). Using the Monte Carlo code PHITS, we simulated the ambient dose equivalent distribution the X-ray fluoroscopy room without the presence of protective plates. Assuming the dose at each voxel was all contributed from radiations in the direction indicated by the directional vector, the shielding effect of the protective plates for the dose at the voxel was determined whether the line toward backtrace of the directional vector has a intersect with the protective plate or not. With SCV, the computational time for the whole dose distribution with the presence of a protective plate was reduced approximately 1/6000 of the full PHITS simulation keeping the good accuracy to evaluate the effect of the plate.
Suzuki, Seiya; Katsube, Daiki*; Yano, Masahiro; Tsuda, Yasutaka; Terasawa, Tomoo; Ozawa, Takahiro*; Fukutani, Katsuyuki; Kim, Y.*; Asaoka, Hidehito; Yuhara, Junji*; et al.
Small Methods, 9(3), p.2400863_1 - 2400863_9, 2025/03
Times Cited Count：5 Percentile：33.08(Chemistry, Physical)
/
/-rays radiolysis (Contract research); FY2022 Nuclear Energy Science & Technology and Human Resource Development ProjectCollaborative Laboratories for Advanced Decommissioning Science; Tohoku University*
JAEA-Review 2024-019, 102 Pages, 2024/09
JAEA-Review-2024-019.pdf:4.4MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2022. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2020, this report summarizes the research results of the "Development of a new corrosion mitigation technology using nanobubbles toward corrosion mitigation in PCV system under the influence of //-rays radiolysis" conducted from FY2020 to FY2022. The present study aims to corrosion, which is considered to be an important factor in the aging degradation of confinement functions (PCV, negative pressure maintenance system, etc.) during the fuel debris removal process. If the chemical species (especially HO) generated by radiolysis become locally concentrated in the areas where short-range - and -radiation emitting nuclides come into contact, the corrosion of steels may be greatly accelerated in those areas.
Micheau, C.; Ueda, Yuki; Motokawa, Ryuhei; Akutsu, Kazuhiro*; Yamada, Norifumi*; Yamada, Masako*; Moussaoui, S. A.*; Makombe, E.*; Meyer, D.*; Berthon, L.*; et al.
Journal of Molecular Liquids, 401, p.124372_1 - 124372_12, 2024/05
Times Cited Count：4 Percentile：48.43(Chemistry, Physical)-GaO(001)Tsai, Y. H.*; Kobata, Masaaki; Fukuda, Tatsuo; Tanida, Hajime; Kobayashi, Toru; Yamashita, Yoshiyuki*
Applied Physics Letters, 124(11), p.112105_1 - 112105_5, 2024/03
Times Cited Count：6 Percentile：41.54(Physics, Applied), , and X-rays (Contract research); FY2022 Nuclear Energy Science & Technology and Human Resource Development ProjectCollaborative Laboratories for Advanced Decommissioning Science; Japan Chemical Analysis Center*
JAEA-Review 2023-022, 93 Pages, 2023/12
JAEA-Review-2023-022.pdf:4.7MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2022. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2020, this report summarizes the research results of the "Development of rapid and sensitive radionuclide analysis method by simultaneous analysis of , , and X-rays" conducted from FY2020 to FY2022. The present study aims to enable rapid analysis of radionuclides in fuel debris and waste, we have established the latest measurement system, such as the multiple -ray detection methods, and the Spectral Determination Method (hereinafter referred to as "SDM") was developed. In the research in 2022, we developed a code that handles measurement data of LSC, singles Ge, and 2D spectra (multiple ). In addition, to develop an integrated database, spectral data of 40 nuclides were obtained by actual measurements and simulation calculations.
PtAl
Ota, Kyugo*; Watabe, Yuki*; Haga, Yoshinori; Iesari, F.*; Okajima, Toshihiko*; Matsumoto, Yuji*
Symmetry (Internet), 15(8), p.1488_1 - 1488_13, 2023/07
Times Cited Count：3 Percentile：32.24(Multidisciplinary Sciences)
X-ray synchrotron diffractionLi, H.*; Liu, Y.*; Zhao, W.*; Liu, B.*; Tominaga, Aki; Shobu, Takahisa; Wei, D.*
International Journal of Plasticity, 165, p.103612_1 - 103612_20, 2023/06
Times Cited Count：51 Percentile：97.57(Engineering, Mechanical)In order to clarify the strength properties of Co-free maraging steel, tensile experiment using high energy synchrotron X-ray diffraction was performed. Diffraction profiles from the martensitic and austenitic phases were obtained, and their strength and width were observed to vary as loading. Analysis of the diffraction profiles showed that the content of martensite in the as-aged material decreased slowly at low stress levels and decreased rapidly at high stress levels. On the other hand, the austenite phase in the as-solution materials was significantly transformed the martensite phase as the stress increased. It was clarified to be responsible for their respective strength properties.
Tsai, T.-H.; Sasaki, Shinji; Maeda, Koji
Journal of Nuclear Science and Technology, 60(6), p.715 - 723, 2023/06
Times Cited Count：1 Percentile：9.47(Nuclear Science & Technology)Iyota, Muneyoshi*; Matsuda, Tomoki*; Sano, Tomokazu*; Shigeta, Masaya*; Shobu, Takahisa; Yumoto, Hirokatsu*; Koyama, Takahisa*; Yamazaki, Hiroshi*; Semba, Yasunori*; Ohashi, Haruhiko*; et al.
Journal of Manufacturing Processes, 94, p.424 - 434, 2023/05
Times Cited Count：14 Percentile：66.79(Engineering, Manufacturing)