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Luu, V. N.; Taniguchi, Yoshinori; Udagawa, Yutaka; Katsuyama, Jinya
Nuclear Engineering and Design, 442, p.114222_1 - 114222_15, 2025/10
Yin, 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:0Johansen, M. P.*; Gwynn, J. P.*; Carpenter, J. G.*; Charmasson, S.*; Mori, Airi; Orr, B.*; Simon-Cornu, M.*; Osvath, I.*; McGinnity, P.*
Journal of Environmental Radioactivity, 287, p.107706_1 - 107706_8, 2025/07
Times Cited Count:0Gu, G. H.*; Jeong, S. G.*; Heo, Y.-U.*; Harjo, S.; Gong, W.; Cho, J.*; Kim, H. S.*; 4 of others*
Journal of Materials Science & Technology, 223, p.308 - 324, 2025/07
Times Cited Count:0 Percentile:0.00(Materials Science, Multidisciplinary)Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*
JAEA-Review 2025-001, 94 Pages, 2025/06
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 FY2019, this report summarizes the research results of the "Human resource development related to remote control technology for monitoring inside RPV pedestal during retrieval of fuel debris" conducted from FY2019 to FY2023. The present study aims to construct a monitoring platform for understanding the status inside a reactor during fuel debris removal, and measurement and visualization by sensors moving on the platform. In addition, to develop research personnel through research education by participating in such research projects, classroom lectures, and facility tours is also a goal of this project. In FY2023, along with the verification of each system, a three-dimensional reconstruction model was generated using images acquired from a moving camera on the monitoring platform in a simulated environment, and an integrated experiment was conducted to demonstrate that it is possible to present images from the optimal viewpoint for the visualization target, with the cooperation of each research theme.
Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*
JAEA-Review 2024-064, 118 Pages, 2025/06
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 (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 FY2019, this report summarizes the research results of the "Development of extremely small amount analysis technology for fuel debris analysis" conducted from FY2019 to FY2023. Understanding the properties of fuel debris is necessary for handling, criticality control, storage control, etc. A key technique is the chemical analysis of actinide nuclides. We developed sample pretreatment technology and separation / analysis process required for chemical analysis. The purpose of this study is to streamline future planned fuel debris analysis. To promote 1F decommissioning, we will train human resources through on-the-job training. In particular, we applied the extremely small amount analysis (ICP-MS/MS), which has recently been successful in the fields of analytical chemistry and radiochemistry, to the nuclear field. This method allows high-accuracy analysis without pretreatment to isolate the nuclide to be measured. The separation pretreatment can be skipped and a rapid analysis process can be established.
Yoshida, Kazuo; Hiyama, Mina*; Tamaki, Hitoshi
JAEA-Research 2025-003, 24 Pages, 2025/06
An accident of evaporation to dryness by boiling of high-level radioactive liquid waste (HLLW) is postulated as one of the severe accidents caused by the loss of cooling function at a fuel reprocessing plant. In this case, volatile radioactive materials, such as ruthenium (RuO) are released from the tanks with water and nitric-acid mixed vapor into the atmosphere. Accurate quantitative estimation of released Ru is one of the important issues for risk assessment of those facilities. RuO
is expected to be absorbed chemically into water dissolving nitrous acid. Condensation of mixed vapor plays an important role for Ru transporting behavior in the facility building. The thermal-hydraulic behavior in the facility building is simulated with MELCOR code. The latent heat, which is a governing factor for vapor condensing behavior, has almost same value for nitric acid and water at the temperature range under 120 centigrade. Considering this thermal characteristic, it is assumed that the amount of nitric acid is substituted with mole-equivalent water in MELCOR simulation. Compensating modeling induced deviation by this assumption have been assembled with control function features of MELCOR. The comparison results have been described conducted between original simulation and modified simulation with compensating model in this report. It has been revealed that the total amount of pool water in the facility was as same as both simulations.
Sugita, Yutaka; Ono, Hirokazu; Beese, S.*; Pan, P.*; Kim, M.*; Lee, C.*; Jove-Colon, C.*; Lopez, C. M.*; Liang, S.-Y.*
Geomechanics for Energy and the Environment, 42, p.100668_1 - 100668_21, 2025/06
The international cooperative project DECOVALEX 2023 focused on the Horonobe EBS experiment in the Task D, which was undertaken to study, using numerical analyses, the thermo-hydro-mechanical (or thermo-hydro) interactions in bentonite based engineered barriers. One full-scale in-situ experiment and four laboratory experiments, largely complementary, were selected for modelling. The Horonobe EBS experiment is a temperature-controlled non-isothermal experiment combined with artificial groundwater injection. The Horonobe EBS experiment consists of the heating and cooling phases. Six research teams performed the THM or TH (depended on research team approach) numerical analyses using a variety of computer codes, formulations and constitutive laws.
Birkholzer, J. T.*; Graupner, B. J.*; Harrington, J.*; Jayne, R.*; Kolditz, O.*; Kuhlman, K. L.*; LaForce, T.*; Leone, R. C.*; Mariner, P. E.*; McDermott, C.*; et al.
Geomechanics for Energy and the Environment, 42, p.100685_1 - 100685_17, 2025/06
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
We explore the structures of dry and hydrated (HO and D
O) 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 Na
Si
O
melt, whereas the compression of dry Na
Si
O
at 0-10 GPa and 3000 K is governed largely by bending of the Si-O-Si angle. The molecular dynamics simulations on hydrous Na
Si
O
melts further suggest that the sodium ions are scavenged from its network-modifying role via 2(
Si-O
+ Na
)
Si-(O-
Si-O)
+ 2Na
and Si-O
+ Na
+ Si-OH
Si-(O-H-O-Si)
+ Na
with increasing pressure.
Fukushima, Masahiro; Ando, Masaki; Nagaya, Yasunobu
Nuclear Science and Engineering, 199(6), p.1029 - 1043, 2025/06
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)Li, X.; Yamaji, Akifumi*; Sato, Ikken*; Yamashita, Takuya
Annals of Nuclear Energy, 214, p.111217_1 - 111217_13, 2025/05
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)Wilson, J.*; Sasamoto, Hiroshi; Tachi, Yukio; Kawama, Daisuke*
Applied Clay Science, 275, p.107862_1 - 107862_15, 2025/05
Times Cited Count:0High-Level Radioactive Waste (HLW) repositories include iron or steel-based containers/overpack and bentonite buffers. Over the last 25 years or so, research efforts have attempted to elucidate the nature of iron-bentonite interactions, especially the potential for the deleterious alteration of the swelling clay component (smectite), to iron-rich layer silicates, some of which lack the capacity for intracrystalline swelling. This could result in a reduction or loss in swelling pressure in the bentonite buffer which is designed to protect waste containers from shear forces and also acts to restrict water and solute transport, as part of an engineered barrier system. Most data on iron-bentonite interactions come from experimental and geochemical modelling studies, as natural analogue data are lacking. The data suggests that there is the potential for the development of an iron-rich bentonite alteration zone with smectite (generally present as the aluminous montmorillonite type) undergoing alteration to iron-rich solids, including layer silicates and steel corrosion products such as green rust or magnetite. The evidence available is complex, arguably incomplete, with many potential complex couplings. Many uncertainties remain despite efforts taken over the last 25 years, but plausible scenarios for iron-bentonite interactions have been identified and possible implications for buffer properties have been suggested.
Mori, Airi; Johansen, M. P.*; McGinnity, P.*; Takahara, Shogo
Communications Earth & Environment (Internet), 6, p.356_1 - 356_11, 2025/05
Times Cited Count:0Fablet, L.*; Pdrot, M.*; Choueikani, F.*; Kieffer, I.*; Proux, O.*; Pierson-Wickmann, A.-C.*; Cagniart, V.*; Yomogida, Takumi; Marsac, R.*
Environmental Science; Nano, 12(5), p.2815 - 2827, 2025/05
Times Cited Count:0 Percentile:0.00(Chemistry, Multidisciplinary)Nickel is an omnipresent trace element in the environment. Due to its high affinity for iron oxide nanoparticles, its elimination from soils and water by these nanoparticles represents an interesting strategy, specially by magnetites, which is naturally present in the environment. However, the interactions between Ni and magnetite are poorly understood, because of the difficulty to control the stoichiometry (Fe(II)-to-Fe(III) ratio) of magnetite. The behavior of Ni in the presence of magnetite nanoparticles with different stoichiometries, in aqueous solution and inert atmosphere, are probed by adsorption experiments and X-ray Absorption Spectroscopy. This study helps predicting the interactions between Ni and magnetite in environmental conditions, which can be used for the development of efficient remediation strategies.
Usami, Hiroshi; Yoshinaga, Kyohei*; Fujikawa, Keigo*
Nihon Genshiryoku Gakkai-Shi ATOMO, 67(5), p.295 - 299, 2025/05
no abstracts in English
Fukuda, Kodai; Obara, Toru*; Suyama, Kenya
Nuclear Technology, 211(5), p.963 - 973, 2025/05
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)Nagatani, Taketeru; Kosuge, Yoshihiro*; Sagara, Hiroshi*; Nakaguki, Sho; Nomi, Takayoshi; Okumura, Keisuke
Progress in Nuclear Science and Technology (Internet), 7, p.41 - 46, 2025/05
Ouchi, Kazuki; Ueno, Katsuhiro; Watanabe, Masayuki
Scientific Reports (Internet), 15, p.18515_1 - 18515_7, 2025/05
Times Cited Count:0We first demonstrate a nonaqueous rechargeable battery using uranium and iron as active materials. This uranium-iron battery achieves an open-circuit voltage of approximately 1.3 V, exhibits stable cycling performance, and delivers a good Coulombic efficiency of 862%. These characteristics suggest a promising avenue for utilizing depleted uranium in innovative applications.
Ito, Tatsuya; Ogawa, Yuhei*; Gong, W.; Mao, W.*; Kawasaki, Takuro; Okada, Kazuho*; Shibata, Akinobu*; Harjo, S.
Acta Materialia, 287, p.120767_1 - 120767_16, 2025/04
Times Cited Count:0 Percentile:0.00(Materials Science, Multidisciplinary)