Design of a storage ring based on a fixed-field alternating-gradient configuration with an internal target for heavy-ion beams with stochastic charge state conversions

Ishi, Yoshihiro*; Uesugi, Tomonori*; Mori, Yoshiharu*; Nishio, Katsuhisa

Physical Review Accelerators and Beams (Internet), 29(5), p.050101_1 - 050101_14, 2026/05

https://doi.org/10.1103/th5l-mq3q

Development of elemental technologies of hand-foot-cloth monitors for -contamination visualization (Contract research); FY2023 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*

JAEA-Review 2025-021, 63 Pages, 2025/10

JAEA-Review-2025-021.pdf:5.71MB

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 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 FY2022, this report summarizes the research results of the "Development of elemental technologies of hand-foot-cloth monitors for -contamination visualization" conducted in FY2023. The present study aims to develop hand-foot-monitors for -contamination visualization and cloth monitors for /-contamination visualization consisting of a portable phoswich detector. ZnS(Ag) thick films by AD method and rare earth complexes have been studied for development of -ray scintillator materials. The scintillator properties of the newly prepared ZnS(Ag) thick films were improved from those prepared in 2022. A rare earth complex shows strong emission intensity under -ray irradiation, which was 12.5 times higher than that of a commercially available plastic scintillator (Saint-Gobain, BC400). By optimizing the manufacturing process conditions (molding die, sintering conditions, cutting process, annealing conditions, grinding/polishing processes) for La-GPS polycrystalline thin plates, the preparing process for 50 mm square La-GPS was established. The prepared La-GPS provided excellent performance for -ray scintillators. The cloth monitors for /-contamination visualization were also improved for the reflection of the actual situation. Furthermore, the basic performance of the prototype cloth monitors was evaluated, and alpha-ray energy and position distribution information were obtained. In an evaluation test of the phoswich detector, a precise discrimination between - and -rays was achieved.

Nacre-like MXene/polyacrylic acid layer-by-layer multilayers as hydrogen gas barriers

Auh, Y. H.*; Neal, N. N.*; Arole, K.*; Regis, N. A.*; Nguyen, T.*; Ogawa, Shuichi*; Tsuda, Yasutaka; Yoshigoe, Akitaka; Radovic, M.*; Green, M. J.*; et al.

ACS Applied Materials & Interfaces, 17(21), p.31392 - 31402, 2025/05

https://doi.org/10.1021/acsami.5c03632

Opposing mixed convection heat transfer for turbulent single-phase flows (Contract research, Translated document)

Motegi, Kosuke; Shibamoto, Yasuteru; Hibiki, Takashi*; Tsukamoto, Naofumi*; Kaneko, Junichi*

JAEA-Review 2024-039, 45 Pages, 2024/09

JAEA-Review-2024-039.pdf:2.23MB

Several heat transfer correlations have been reported related to single-phase opposing flow; however, these correlations are based on experiments conducted in various channel geometries, working fluids, and thermal flow parameter ranges. Therefore, establishing a guideline for deciding which correlation should be selected based on its range of applicability and extrapolation performance is important. This study reviewed the existing heat transfer correlations for turbulent opposing-flow mixed convection. Furthermore, the authors evaluated the predictive performance of each correlation by comparing them with the experimental data obtained under various experimental conditions. The Jackson and Fewster, Churchill, and Swanson and Catton correlations can accurately predict all the experimental data. The authors confirmed that heat transfer correlations using the hydraulic-equivalent diameter as a characteristic length can be used for predictions regardless of channel-geometry differences. Furthermore, correlations described based on nondimensional dominant parameters can be used for predictions regardless of the differences in working fluids.

Development of elemental technologies of hand-foot-cloth monitors for -contamination visualization (Contract research); FY2022 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*

JAEA-Review 2024-006, 54 Pages, 2024/06

JAEA-Review-2024-006.pdf:2.21MB

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 (1F), 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 FY2022, this report summarizes the research results of the "Development of elemental technologies of hand-foot-cloth monitors for -contamination visualization" conducted in FY2022. The present study aims to develop hand-foot-monitors for -contamination visualization and cloth monitors for /-contamination visualization consisting of a portable phoswich detector for measuring /-contamination distribution and energy to ensure the safety and security of workers involved in the decommissioning project of the 1F. The possibility of practical application of new scintillator materials and devices was examined with the goal of developing such new instruments.

Ion-pairing extraction and their reaction modeling of anionic M-Cl species with cationic NTAamide(C6) extractant and comparison with density functional theory calculations

Kinoshita, Ryoma; Sasaki, Yuji; Kaneko, Masashi; Matsumiya, Masahiko*; Shinoku, Kota*; Shiroishi, Hidenobu*

Hydrometallurgy, 222, p.106159_1 - 106159_12, 2023/10

https://doi.org/10.1016/j.hydromet.2023.106159

Solvent extraction is conducted using a total of 20 metals revealing high stability constants with Cl and hexahexyl-nitrilotriacetamide (NTAamide(C6)) extractant. The metals used here may behave as anions at high Cl concentrations, and NTAamide(C6), which contains a tertiary N atom, is protonated under acidic conditions. Most of the metal ions in this study display higher distribution ratios (D(M)) from HCl than those from HNO, and exhibit 1:1 stoichiometries with NTAamide. Following the experimental results, the association constants and distribution coefficients of the group 12 elements are calculated via ion-pair extraction modeling using density functional theory calculations, and the simulations of D yield calculated values with the same trend as that of the measured values.

EBR-II MOX fuel characterization enabling ARES Phase I testing

Bess, J. D.*; Chipman, A. S.*; Pope, C. L.*; Jensen, C. B.*; Ozawa, Takayuki; Hirooka, Shun; Kato, Masato*

Nuclear Science and Engineering, 197(8), p.1845 - 1872, 2023/08

https://doi.org/10.1080/00295639.2022.2156240

Pretransient characterization was performed for the EBR-II MOX fuel pellets from the SPA-2/-2B Operational Reliability Testing collaboration between Japan and US. The continued collaboration will investigate the transient performance of these rods in TREAT at Idaho National Laboratory. The results will fill a gap in existing transient performance data for MOX as these rods have a peak burnup of ~134.4 GWd/t in the EBR-II. Fuel pellet properties were gathered from available resources and their irradiation and decay history evaluated. Further reactor physics calculations were performed to support the experiment design, reactor operations, and safety analyses necessary to enable the programmatic success. Of the three irradiated fuel pins, two will undergo transient testing, and all three will undergo post-irradiation examination.

The Effects of unburned-gas temperature and pressure on the unstable behavior of cellular-flame fronts generated by intrinsic instability in hydrogen-air lean premixed flames under adiabatic and non-adiabatic conditions; Numerical simulation based on the detailed chemical reaction model

Thwe Thwe, A.; Kadowaki, Satoshi; Nagaishi, Ryuji

Journal of Nuclear Science and Technology, 60(6), p.731 - 742, 2023/06

https://doi.org/10.1080/00223131.2022.2143448

In this study, we performed numerical calculations of unsteady reaction flow considering detailed chemical reactions, investigated the unstable behavior of hydrogen-air dilute premixed flame due to intrinsic instability, and clarified the effects of unburned gas temperature and pressure. I made it. The unstable behavior of the flame in a wide space was simulated, and the burning rate of the cellular flame was obtained. Then, the effects of heat loss and flame scale on flame unstable behavior were investigated. The burning velocity of a planar flame increases as the unburned-gas temperature increases and it decreases as the unburned-gas pressure and heat loss increase. The normalized burning velocity increases when the pressure increases and heat loss becomes large, and it decreases when the temperature increases. This is because the high unburned-gas pressure and heat loss promote the unstable behavior and instability of flame.

Unusually kinetically inert monocationic neptunyl complex with a fluorescein-modified 1,10-phenanthroline-2,9-dicarboxylate ligand; Specific separation and detection in gel electrophoresis

Yamagata, Kazuhito*; Ouchi, Kazuki; Marumo, Kazuki*; Tasaki-Handa, Yuiko*; Haraga, Tomoko; Saito, Shingo*

Inorganic Chemistry, 62(2), p.730 - 738, 2023/01

https://doi.org/10.1021/acs.inorgchem.2c02908

The inert NpO complex with a fluorescein-modified phenanthroline-2,9-dicarboxylic acid was found by kinetic selection using polyacrylamide gel electrophoresis (PAGE) from a small chemical library. The small spontaneous dissociation rate constant of 810 s (the half-life of 23 hours) was determined. This is the singly-charged NpO complex exhibiting unusual kinetic inertness in aqueous solution, one million times slower than widely accepted fast kinetics of neptunyl complexes. Selective fluorescence detection of NpO was achieved in PAGE with a detection limit of 68 pmol dm(17 fg). This system was successfully applied to simulated spent nuclear fuel and high-level radioactive waste samples.

Rotation of complex ions with ninefold hydrogen coordination studied by quasielastic neutron scattering and first-principles molecular dynamics calculations

Omasa, Yoshinori*; Takagi, Shigeyuki*; Toshima, Kento*; Yokoyama, Kaito*; Endo, Wataru*; Orimo, Shinichi*; Saito, Hiroyuki*; Yamada, Takeshi*; Kawakita, Yukinobu; Ikeda, Kazutaka*; et al.

Physical Review Research (Internet), 4(3), p.033215_1 - 033215_9, 2022/09

https://doi.org/10.1103/PhysRevResearch.4.033215