Muon spin relaxation in mixed perovskite (LaAlO)(SrAlTaO) with

Ito, Takashi; Higemoto, Wataru; Koda, Akihiro*; Nakamura, Jumpei*; Shimomura, Koichiro*

Interactions (Internet), 245(1), p.25_1 - 25_7, 2024/12

https://doi.org/10.1007/s10751-024-01866-5

Quantitative analysis of microstructure evolution, stress partitioning and thermodynamics in the dynamic transformation of Fe-14Ni alloy

Li, L.*; Miyamoto, Goro*; Zhang, Y.*; Li, M.*; Morooka, Satoshi; Oikawa, Katsunari*; Tomota, Yo*; Furuhara, Tadashi*

Journal of Materials Science & Technology, 184, p.221 - 234, 2024/06

https://doi.org/10.1016/j.jmst.2023.10.037

Development of a hybrid method for evaluating the long-term structural soundness of nuclear reactor buildings using response monitoring and damage imaging technologies (Contract research); FY2022 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2023-048, 151 Pages, 2024/05

JAEA-Review-2023-048.pdf:8.48MB

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 FY2021, this report summarizes the research results of the "Development of a hybrid method for evaluating the long-term structural soundness of nuclear reactor buildings using response monitoring and damage imaging technologies" conducted in FY2022. The present study aims to develop an evaluation method necessary to obtain a perspective on the long term structural soundness of accident-damaged reactor buildings, where accessibility to work sites is extremely limited due to high radiation dose rate and high contamination. In FY2022, the second year of the three-year plan, some tests and other activities on the following research items were conducted following FY2021, based on the specific research methods and research directions clarified in FY2021.

Experimental investigation on local flow structures of upward cap-bubbly flows in a vertical large-size square channel

Sun, Haomin; Kunugi, Tomoaki*; Yokomine, Takehiko*; Shen, X.*; Hibiki, Takashi*

Experimental Thermal and Fluid Science, 154, p.111171_1 - 111171_24, 2024/05

https://doi.org/10.1016/j.expthermflusci.2024.111171

Organization of malonamides from the interface to the organic bulk phase

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

https://doi.org/10.1016/j.molliq.2024.124372

Supramolecular organization of extractant molecules impacts metal ions separation behavior. Probing bulk and interfacial structures of the relevant systems is expected to provide key insights into the metal ion selectivity and kinetic aspects. The supramolecular features of two solvent extraction systems based on malonamide extractants THMA in toluene and DBMA in n-heptane were studied using small-angle X-ray scattering for the organic bulk phases, as well as interfacial tension and neutron reflectivity measurements for the interfaces. In the bulk solution, THMA forms dimeric/trimeric associates but no aggregates in toluene, while DBMA forms large aggregates in n-heptane. On the other hand, THMA accumulates in a diffuse layer at the interface at high THMA concentration, whereas DBMA forms a compact but thinner layer. After Pd(II) extraction, the thickness of interfacial layers decreases in the case of THMA, and totally vanishes in the case of DBMA. Based on these new structural information, two mechanisms are proposed for Pd(II) and Nd(III) extraction with malonamides. In toluene, THMA associates slightly accumulate in the vicinity of the interface, then coordinate Pd(II) and diffuse into the organic bulk phase. In n-heptane, DBMA aggregates adsorb at the interface then pick up Nd(III) cations in their polar cores and finally diffuse into the bulk.

First demonstration of a single-end readout position-sensitive optical fiber radiation sensor inside the Fukushima Daiichi Nuclear Power Station based on wavelength-resolving analysis

Terasaka, Yuta; Sato, Yuki; Uritani, Akira*

Nuclear Instruments and Methods in Physics Research A, 1062, p.169227_1 - 169227_6, 2024/05

https://doi.org/10.1016/j.nima.2024.169227

Stochastic ray tracing for Fresnel diffraction

Seto, Keita

Optics Express (Internet), 32(10), p.16999 - 17011, 2024/05

https://doi.org/10.1364/OE.521317

Determination of Sr in highly radioactive aqueous samples via conversion to a kinetically stable 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid complex followed by concentration-separation-fractionation based on capillary electrophoresis-liquid scintillation

Ouchi, Kazuki; Haraga, Tomoko; Hirose, Kazuki*; Kurosawa, Yuika*; Sato, Yoshiyuki; Shibukawa, Masami*; Saito, Shingo*

Analytica Chimica Acta, 1298, p.342399_1 - 342399_7, 2024/04

https://doi.org/10.1016/j.aca.2024.342399

Given that conventional methods of high-dose sample analysis pose substantial exposure risks and generate large amounts of secondary radioactive waste, faster procedures allowing for decreased radiation emission are highly desirable. To address this need, we developed a Sr quantitation technique that is based on liquid scintillation counting-coupled capillary transient isotachophoresis (ctITP) with two-point detection and relies on the rapid concentration, separation, and fractionation of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-complexed Sr in a single run. This method, which allows for the handling of high-dose radioactive specimens at the microliter level and is substantially faster than conventional ion-exchange protocols, was used to selectively quantify Sr in real high-dose waste. The successful concentration-separation in ctITP was ascribed to the inertness of the Sr-DOTA complex to dissociation.

Electrochemical behavior of neptunium in NaCl-2CsCl melt

Hayashi, Hirokazu; Minato, Kazuo*

Electrochemistry (Internet), 92(4), p.043020_1 - 043020_5, 2024/04

https://doi.org/10.5796/electrochemistry.23-69159

The electrochemical behavior of neptunium in NaCl-2CsCl melt at 823-923 K was investigated by cyclic voltammetry, differential pulse voltammetry, and open-circuit chronopotentiometry after polarization. The results show that Np ions are reduced to Np metal by a two-step mechanism via Np ions in NaCl-2CsCl melt. The diffusion coefficients of Np and Np ions were determined from cyclic voltammograms. The apparent standard potentials of Np/Np and Np/Np redox couples have been determined to be E(Np/Np) = -3.353 + 7.6710T, and E(Np/Np) = -1.175 + 4.9910 T vs. Cl/Cl (V), respectively. The activity coefficients of Np and Np ions were also determined using the reported data on the Gibbs free energy of formation for NpCl and NpCl in supercooled liquid state.

Field-induced insulator-metal transition in EuTe

Takeuchi, Tetsuya*; Honda, Fuminori*; Aoki, Dai*; Haga, Yoshinori; Kida, Takanori*; Narumi, Yasuo*; Hagiwara, Masayuki*; Kindo, Koichi*; Karube, Kosuke*; Harima, Hisatomo*; et al.

Journal of the Physical Society of Japan, 93(4), p.044708_1 - 044708_10, 2024/04

https://doi.org/10.7566/JPSJ.93.044708