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Dechenaux, B.*; Brovchenko, M.*; Araki, Shohei; Gunji, Satoshi; Suyama, Kenya
Annals of Nuclear Energy, 223, p.111555_1 - 111555_11, 2025/12
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Nakagawa, Hiroshi; Ubbink, J.*
Food Hydrocolloids, 168, p.111453_1 - 111453_9, 2025/12
Times Cited Count：1 Percentile：0.00(Chemistry, Applied)The molecular mechanism of plant protein texturization under extrusion conditions was unraveled at the secondary structure level by decoupling the effects of heating, cooling and shearing on protein secondary structure. Upon heating without shearing, native alpha-helices and intramolecular-beta-sheets unfold to random domains, followed by the formation of intermolecular beta-sheets, inducing aggregation. During cooling, the intermolecular beta-sheets become increasingly ordered, and random domains partially fold into non-native beta-structures. Combined heating and shearing results in more extensive beta-sheets than heating alone. The resulting beta-rich structures provide for an entangled network of protein chains and a cohesive protein matrix.
Dei, Shuntaro; Shibata, Masahito*; Negishi, Kumi*; Sugiura, Yuki; Amano, Yuki; Bateman, K.*; Wilson, J.*; Yokoyama, Tatsunori; Kagami, Saya; Takeda, Masaki; et al.
Results in Earth Sciences (Internet), 3, p.100097_1 - 100097_16, 2025/12
Interactions between cement and host rock in geological repositories for radioactive waste will result in a chemically disturbed zone, which may potentially affect the long-term safety. This paper investigates the chemical evolution at the interface between cement (Ordinary Portland Cement: OPC and Low Alkaline Cement: LAC) and mudstone after 11 years of in situ reactions at the Horonobe Underground Research Laboratory. The study combines various analytical techniques to identify the key reactions at the cement-rock interface, including cement dissolution, precipitation of secondary minerals such as calcite and C-(A-)S-H phases, cation exchange in montmorillonite and reduced porosity in mudstone. The study also highlights the effects of cement-mudstone interactions on radionuclide migration, such as reduction of diffusivity due to reduced porosity and enhancement of sorption due to incorporation into secondary minerals in the altered mudstone.
Koarashi, Jun; Nagano, Hirohiko*; Nakayama, Masataka*; Atarashi-Andoh, Mariko; Nagaoka, Mika
Chemosphere, 389, p.144715_1 - 144715_11, 2025/11
Radiocesium (
Cs) contamination poses a long-term ecological challenge, particularly in forest ecosystems. The role of soil microorganisms in determining its fate remains insufficiently understood. This study presents a dynamic assessment of microbial Cs retention, focusing on the complex interplay among microorganisms, organic matter, and clay minerals within the organic layer-mineral soil system. Our results show that rapid microbial cycling sustains a potentially bioavailable Cs pool in the organic layer. This microbial involvement diminishes as Cs activity concentrations in the organic layer decline. In the mineral soil, minimal microbial Cs retention was observed, suggesting an indirect role in facilitating Cs immobilization by clay minerals. Notably, microbial Cs retention in the organic layer is regulated by Cs availability, independent of region, forest type, and time since deposition. These findings provide a unified explanation for observed differences in Cs persistence in organic layers between European and Japanese forests.
C-stainless steel composites using the improved MPS methodAhmed, Z.*; Wu, S.*; Sharma, A.*; Kumar, R.*; Yamano, Hidemasa; Pellegrini, M.*; Yokoyama, Ryo*; Okamoto, Koji*
International Journal of Heat and Mass Transfer, 250, p.127343_1 - 127343_17, 2025/11
Times Cited Count：2 Percentile：0.00(Thermodynamics)Asamori, Koichi; Sueoka, Shigeru; Komatsu, Tetsuya; Ogata, Manabu; Uchida, Mao; Nishiyama, Nariaki; Tanaka, Kiriha; Kobayashi, Tomoharu; Mitsuguchi, Takehiro; Murakami, Osamu; et al.
JAEA-Review 2025-035, 29 Pages, 2025/10
JAEA-Review-2025-035.pdf:1.12MB
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2025. The objectives and contents of this research are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.
Asamori, Koichi; Sueoka, Shigeru; Kobayashi, Tomoharu; Nishiyama, Nariaki; Tanaka, Kiriha; Murakami, Osamu; Fukuda, Shoma; Ogata, Manabu; Uchida, Mao; Komatsu, Tetsuya; et al.
JAEA-Research 2025-007, 99 Pages, 2025/10
JAEA-Research-2025-007.pdf:12.36MB
This annual report documents the progress of research and development (R&D) in the 3rd fiscal year of the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028) to provide the scientific base for assessing geosphere stability for long-term isolation of high-level radioactive waste. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. The current status of R&D activities with previous scientific and technological progress is summarized.
Hagiwara, Hiroki; Watanabe, Yusuke; Konishi, Hiromi*; Funaki, Hironori; Fujiwara, Kenso; Iijima, Kazuki
Applied Geochemistry, 190, p.106490_1 - 106490_10, 2025/10
Times Cited Count：0
CPham, V. H.; Kurata, Masaki; Nagae, Yuji; Ishibashi, Ryo*; Sasaki, Masana*
Corrosion Science, 255, p.113098_1 - 113098_9, 2025/10
Times Cited Count：1 Percentile：0.00(Materials Science, Multidisciplinary)Reiser, J. T.*; Neeway, J. J.*; Cooley, S. K.*; Parruzot, B.*; Heredia-Langner, A.*; Gin, S.*; Thomas, M.*; Smith, N. J.*; Icenhower, J. P.*; Stone-Weiss, N.*; et al.
International Journal of Applied Glass Science, 16(4), p.e16707_1 - e16707_16, 2025/10
Times Cited Count：0 Percentile：0.00(Materials Science, Ceramics)Luu, V. N.; Taniguchi, Yoshinori; Udagawa, Yutaka; Katsuyama, Jinya
Nuclear Engineering and Design, 442, p.114222_1 - 114222_15, 2025/10
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Kubo, Kotaro; Mori, Kenji*; Muramatsu, Ken
Nuclear Engineering and Design, 442, p.114176_1 - 114176_14, 2025/10
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Nakayama, Masashi; Ishii, Eiichi; Hayano, Akira; Aoyagi, Kazuhei; Murakami, Hiroaki; Ono, Hirokazu; Takeda, Masaki; Mochizuki, Akihito; Ozaki, Yusuke; Kimura, Shun; et al.
JAEA-Review 2025-027, 80 Pages, 2025/09
JAEA-Review-2025-027.pdf:6.22MB
The Horonobe Underground Research Laboratory Project is being pursued by the Japan Atomic Energy Agency to enhance the reliability of relevant technologies for geological disposal of high-level radioactive waste through investigating the deep geological environment within the host sedimentary rocks at Horonobe Town in Hokkaido, north Japan. In the fiscal year 2025, we continue R&D on "Study on near-field system performance in geological environment" and "Demonstration of repository design options". These are identified as key R&D challenges to be tackled in the Horonobe underground research plan for the fiscal year 2020 onwards. In the "Study on near-field system performance in geological environment", we continue to obtain data from the full-scale engineered barrier system performance experiment, and work on the specifics of the full-scale engineered barrier system dismantling experiment. As for "Demonstration of repository design options", the investigation, design, and evaluation techniques are to be systemized at various scales, from the tunnel to the pit, by means of an organized set of evaluation methodologies for confinement performance at these respective scales. Preliminary borehole investigations will be conducted within a 500 m gallery, with the objectives of obtaining rock strength and rock permeability data, as well as surveying the extent of the excavation damaged zone surrounding the test tunnel via tomographic analysis. A planning study for the in-situ construction test will be conducted to investigate the construction of backfill material and watertight plugs. The volume of water inflow associated with the excavation of the 500 m gallery will be observed, and its magnitude will be compared with the range of water inflow predicted in the analysis. The test plan to determine the extent of the excavation damaged zone around the pit, which is planned to be constructed in the 500 m gallery, will be studied to determine the in-situ excavation damaged zone. In addition, the investigation and evaluation methods for the amount of water inflow from fractures and the extent of the excavation damaged zone around the pit will be organized. Concerning the construction and maintenance of the subsurface facilities, excavation of the West Access Shaft and the 500 m gallery will continue. It is anticipated that the construction of the facilities will be completed by the end of the fiscal year 2025. In addition, we continue R&D on the following three tasks in the Horonobe International Project; Task A: Solute transport experiment with model testing, Task B: Systematic integration of repository technology options, and Task C: Full-scale engineered barrier system dismantling experiment.
Naganuma, Masayuki; Ikusawa, Yoshihisa; Shuji, Yoshiyuki; Suzuki, Kiichi; Yamada, Yoshikazu; Kamiya, Masayoshi
JAEA-Research 2025-006, 165 Pages, 2025/09
JAEA-Research-2025-006.pdf:5.93MB
As a study for advancing LWR MOX fuel, the fuel concept that can contribute to effective plutonium utilization (e.g. reduction of the number of plu-thermal plants required) and reduction of spent fuel subassemblies (interim storage subassemblies) by using existing reactors was investigated. Specifically, since an increase of Pu loading is effective for the above purposes, MOX fuel candidate concepts with the potential to increase Pu loading in the range of the current MOX fuel guidelines (Pu content: 
13 wt%, burnup: 45 GWd/t, MOX fuel loading: 1/3) for PWRs were identified and compared in terms of "core and fuel design", "front-end", and "back-end", and the promising fuel concept was selected. Consequently, it was found that placing fuel elements with burnable poisons in the periphery (mainly in the corners) and adjusting the power peaking in the subassembly can increase the Pu content of the fuel elements in the periphery compared to the existing MOX fuel, which is effective in increasing the total Pu loading. Based on this measures, several fuel candidate concepts were devised, then each fuel specification that maintain criticality and power peaking equivalent to the existing MOX fuel were evaluated. As a result of the comparison of the characteristics of each candidate, the fuel concept in which UO
-Gd fuel is loaded near the corners was conclusively selected as the most promising concept, because it can increase Pu loading by approximately 15% compared to the existing MOX fuel core and has a lower development burden. Moreover, schematic evaluations were conducted for this fuel concept using the Nuclear Material Balance Analysis Code, confirming the quantitative prospect on how much the above increase in Pu loading would actually affect the number of required plu-thermal plants and the material balance of nuclear fuel cycle.
Mn
N and Fe
Co
N filmsYin, W.*; Ito, Keita*; Tsubowa, Yusuke*; Tsujikawa, Masahito*; Shirai, Masafumi*; Umetsu, Rie*; Takanashi, Koki
Journal of Magnetism and Magnetic Materials, 628, p.173157_1 - 173157_8, 2025/09
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)Tomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka
Journal of Nuclear Science and Technology, 12 Pages, 2025/09
Times Cited Count：0Yamaguchi, Yuji; Kondo, Yasuhiro; Meigo, Shinichiro; Shinozaki, Shinichi; Takayanagi, Tomohiro; Fujimori, Hiroshi*; Kawamura, Naritoshi*
Journal of Physics; Conference Series, 3094(1), p.012023_1 - 012023_5, 2025/09
The 3-GeV proton beam from the rapid cycling synchrotron (RCS) of J-PARC is transported to the spallation neutron source at Materials and Life Science Experimental Facility (MLF) by a 3-GeV RCS to Neutron facility Beam Transport (3NBT) line. Recently, the first design idea of a new proton beam transport line has been proposed for a future target station of the MLF (TS2). In the present study, proton beam transport is simulated near the TS2 target where a bending magnet and a solenoid are located for muon beam transport. The purposes are to clarify the magnetic field effects on the proton beam by the magnets and to present a method to correct each effect. Orbit deviation by the bending magnet and vertical size expansion due to profile rotation by the solenoid can be corrected by installing additional bending magnets and a solenoid with reversal magnetic field, respectively. The correction method is expected to be effective and also needs to be studied further for detail design.
Kamiya, Junichiro; Wada, Kaoru*; Htwe, N. T. T.*
Journal of Vacuum Science and Technology B, 43(5), p.054204_1 - 054204_13, 2025/09
Times Cited Count：0
Cm(
Ti,xn)
Og reaction cross sectionGall, B. J.-P.*; Asai, Masato; Ito, Yuta; Toyoshima, Atsushi*; 30 of others*
Journal of the Physical Society of Japan, 94(9), p.094201_1 - 094201_9, 2025/09
Times Cited Count：0An experiment to search for Og isotopes using the Ti beam impinging on Cm target was performed at RIKEN Nishina Center. The optimal beam energy was determined from the quasielastic barrier distribution extracted from the excitation function of quasielastic backscattering. As a result, no Og decay was found, enabling only an estimation of the sensitivity for one event of 0.27 pb, and the 1
cross section upper limit of 0.50 pb.
Watanabe, Taku*; Maejima, Yui*; Ueda, Yuki; Motokawa, Ryuhei; Takabatake, Ai*; Takeda, Shinichi*; Fudoji, Hiroshi*; Kishikawa, Keiki*; Koori, Michinari*
Langmuir, 41(34), p.22762 - 22773, 2025/09
Times Cited Count：0The assembled structures of melanin particles, i.e., colloidal particles coated with a melanin-like polydopamine (PDA) layer, create vivid structural colors. While the thickness of the PDA layer influences the particle arrangement and optical properties, the underlying mechanism has remained controversial. We demonstrate that the water swelling characteristics of PDA are crucial factors governing the dispersion and aggregation of these particles in solution. Detailed comparisons between dry and wet conditions revealed that the PDA layer readily absorbs water molecules, which leads to significant swelling in the thicker layers. The swelling of the PDA layers determined whether the particles remained dispersed or partially aggregated in the water, ultimately controlling the particle arrangement in the dry state once the water evaporated. These findings provide insights into the self-assembly of colloidal particles and offer a strategy for tuning the periodic particle order. This feature is pivotal for various applications in optical and sensing technologies.
