Modeling the extraction of bound rubber from silica-filled styrene-butadiene rubber with toluene

Tamura, Yukiko*; Arakawa, Masato*; Takenaka, Mikihito*; Nakanishi, Yohei*; Fujinami, So*; Shibata, Motoki*; Yamamoto, Katsuhiro*; Miyata, Noboru*; Yamada, Masako*; Seto, Hideki*; et al.

Polymer, 333, p.128662_1 - 128662_8, 2025/08

https://doi.org/10.1016/j.polymer.2025.128662

Incommensurate antiferromagnetism in UTe under pressure

Knafo, W.*; Thebault, T.*; Raymond, S.*; Manuel, P.*; Khalyavin, D. D.*; Orlandi, F.*; Ressouche, E.*; Beauvois, K.*; Lapertot, G.*; Kaneko, Koji; et al.

Physical Review X, 15(2), p.021075_1 - 021075_16, 2025/05

https://doi.org/10.1103/PhysRevX.15.021075

A Decade of neutron diffraction study of iron hydrides

Aoki, Katsutoshi*; Machida, Akihiko*; Saito, Hiroyuki*; Hattori, Takanori

Koatsuryoku No Kagaku To Gijutsu, 35(1), p.4 - 11, 2025/03

https://doi.org/10.4131/jshpreview.35.4

Iron reacts with hydrogen to form solid solutions with body-centered cubic, face-centered cubic, hexagonal close packed, and double hexagonal close packed structures at high temperatures and high pressures. Neutron diffraction is the most powerful tool for determining the occupation sites and occupancies of hydrogen atoms dissolved in a metal lattice. Structural parameters, including hydrogen occupation sites and occupancies, are refined via Rietveld analysis for neutron diffraction data. We present our expertise in Rietveld refinement of iron hydrides accumulated over 10 years.

Water-intercalated and humidity-responsive lamellar materials by self-assembly of sodium acrylate random copolymers

Horiike, Yuki*; Aoki, Hiroyuki; Ouchi, Makoto*; Terashima, Takaya*

Journal of the American Chemical Society, 147(8), p.6727 - 6738, 2025/02

https://doi.org/10.1021/jacs.4c16219

Sm synchrotron-radiation-based Mssbauer spectroscopy of Sm-based heavy fermion compounds

Tsutsui, Satoshi; Higashinaka, Ryuji*; Mizumaki, Masaichiro*; Kobayashi, Yoshio*; Nakamura, Jin*; Ito, Takashi; Yoda, Yoshitaka*; Matsuda, Tatsuma*; Aoki, Yuji*; Sato, Hideyuki*

Interactions (Internet), 245(1), p.9_1 - 9_10, 2024/12

https://doi.org/10.1007/s10751-024-01851-y

Surface depth analysis of chemical changes in random copolymer thin films composed of hydrophilic and hydrophobic silicon-based monomers induced by plasma treatment as studied by hard X-ray photoelectron spectroscopy and neutron reflectivity measurements

Yamamoto, Katsuhiro*; Imai, Tatsuya*; Kawai, Atsuki*; Ito, Eri*; Miyazaki, Tsukasa*; Miyata, Noboru*; Yamada, Norifumi*; Seto, Hideki*; Aoki, Hiroyuki

ACS Applied Materials & Interfaces, 16(48), p.66782 - 66791, 2024/11

https://doi.org/10.1021/acsami.4c17393

Characterization of mineral composition using PIXE and EXAFS analyses to elucidate the Barium adsorption mechanism

Oguri, Kaori; Hagura, Naoto*; Yamaguchi, Akiko; Okumura, Masahiko; Matsuura, Haruaki*; Tsunashima, Yasumichi; Aoki, Katsumi; Arai, Yoichi; Watanabe, So

Nuclear Instruments and Methods in Physics Research B, 556, p.165516_1 - 165516_8, 2024/11

https://doi.org/10.1016/j.nimb.2024.165516

Ningyo-toge is the uranium mine that has been operated in Japan. Various radioactive elements such as Uranium (U), and Radium (Ra) are still present in the mine ground water with very small amount, and behavior of those elements is not fully understood. In this study, we investigated the composition of metal oxides and clay minerals in a soil of slag deposit at the mine, and systematics of adsorption structure of various ions were examined. Identifying the composition and chemical forms of minerals present in the soil of slag can provide useful information for the safety assessment and evaluation of influence on the surrounding environment.

Evaluation study of fault activity on Shionohira and Kuruma Faults located at the border of Fukushima and Ibaraki Prefecture, Japan

Aoki, Kazuhiro; Imai, Hirotaro; Seshimo, Kazuyoshi; Kimura, Megumi; Kirita, Fumio; Nakanishi, Ryuji

JAEA-Research 2024-005, 177 Pages, 2024/10

JAEA-Research-2024-005.pdf:12.02MB

This study presents a method for evaluating displacements on active faults that lack clear markers of fault offset. The method uses geological surveys, core studies, and chemical analyses along with hydraulic and mechanical tests. We applied this method to three test sites along the Shionohira Fault (Shionohira and Betto sites) and the Kuruma Fault (Minakamikita site). Laboratory friction tests on the fault gouge using a variable-speed, rotating shear friction apparatus were conducted. The samples from the Shionohira and Betto sites showed velocity weakening or strengthening, but no velocity dependence was observed at the Minakamikita site. A small-scale test to induce fault slip was conducted using the SIMFIP method. At the Shionohira site, fault slip can be modeled as a Coulomb rupture and shows a frictional dependence on slip velocity. On the other hand, at the Minakamikita site, a complex response using multiple fractures and slip planes was observed. Based on the water pressure response, the hydraulic properties of the area between the faults were evaluated. The transmissivity and specific storage are larger at Shionohira than at Minakamikita. Fault slip data such as shear plane attitude or shear sense were obtained from core samples and stress inversion analysis was performed. We attempted to elucidate the history of the movement and stress that formed the fracture zone. The results reconstructed five activity stages at Shionohira site and two stages at Minakamikita site. As shown in this report, the frictional properties, fault rupture mode, hydraulic properties and the history of fault motion were found to be different between the Shionohira and Kuruma sites. However, the results are based on a few locational data, so case studies at other sites and more applications to other faults should be considered to improve the reliability of the evaluation.

Project plan of HTTR heat application test facility; Safety design and Safety analysis

Aoki, Takeshi; Hasegawa, Takeshi; Kurahayashi, Kaoru; Nomoto, Yasunobu; Shimizu, Atsushi; Sato, Hiroyuki; Sakaba, Nariaki

Proceedings of 11th International Topical Meeting on High Temperature Reactor Technology (HTR 2024), 6 Pages, 2024/10

Japan Atomic Energy Agency (JAEA) is planning to perform a test named HTTR heat application test coupling HTTR (High temperature engineering test reactor) and a hydrogen production plant. The present study reports results of the safety design and safety analysis for HTTR heat application test facility. As a safety design, safety classification of structures, systems, and components was defined in the test facility based on their safety functions. As a preliminary safety analysis, a thermal-hydraulic analysis was performed with RELAP5 code. The safety analysis revealed that newly identified events for HTTR heat application test facility except for the rupture of heat transfer tube of steam generator was enveloped by the licensing basis events in conventional HTTR. The preliminary analysis proved that the safety criteria is satisfied in the candidate of licensing basis event.

R&D status of digital technology on inverse estimation of radioactive source distributions and related source countermeasures; Fast Digital Twin Tech. in Decommissioning Field: 3D-ADRES-Indoor FrontEnd

Machida, Masahiko; Yamada, Susumu; Kim, M.; Tanaka, Satoshi*; Tobita, Yasuhiro*; Iwata, Ayako*; Aoki, Yuto; Aoki, Kazuhisa; Yanagisawa, Kenichi*; Yamaguchi, Takashi; et al.

RIST News, (70), p.3 - 22, 2024/09

Inside the Fukushima Daiichi Nuclear Power Plant (1F), there are many locations with high radiation levels due to contamination by radioactive materials that leaked from the reactor. These pose a significant obstacle to the smooth progress of decommissioning work. To help solve this issue, the Japan Atomic Energy Agency (JAEA), under a subsidy from the Ministry of Economy, Trade, and Industry's decommissioning and contaminated water management project, is conducting research and development on digital technologies to improve the radiation environment inside the decommissioning site. This project, titled "Development of Technology to Improve the Environment Inside Reactor Buildings (Enhancing Digital Technology for Environment and Source Distribution to Reduce Radiation Exposure)," began in April of FY 2023. In this project, the aim is to develop three interconnected systems: FrontEnd, Pro, and BackEnd. The FrontEnd system, based on the previously developed 3D-ADRES-Indoor (prototype) from FY 2021-2022, will be upgraded to a high-speed digital twin technology usable on-site. The Pro system will carry out detailed analysis in rooms such as the new office building at 1F, while the BackEnd system will serve as a database to centrally manage the collected and analyzed data. This report focuses on the FrontEnd system, which will be used on-site. After point cloud measurement, the system will quickly create a 3D mesh model, estimate the radiation source from dose rate measurements, and refine the position and intensity of the estimated source using recalculation techniques (re-observation instructions and re-estimation). The results of verification tests conducted on Unit 5 are also presented. Furthermore, the report briefly discusses the future research and development plans for this project.