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I neutron capture cross-section in the keV neutron regionRovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Katabuchi, Tatsuya*
Journal of Nuclear Science and Technology, 63(4), p.358 - 369, 2026/04
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Takito, Kiyotaka; Okuda, Yukihiko; Nakamura, Izumi*; Furuya, Osamu*
Haikan Gijutsu, 68(2), p.1 - 7, 2026/02
no abstracts in English
Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Katabuchi, Tatsuya*
Annals of Nuclear Energy, 225, p.111688_1 - 111688_18, 2026/01
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Ueda, Yuki; Kobayashi, Toru; Nakamura, Satoshi; Ban, Yasutoshi; Kaneta, Yui; Nabatame, Nozomi; Micheau, C.; Tokunaga, Kohei; Nakabe, Rintaro; Kaneko, Masashi*; et al.
Langmuir, 42(1), p.1613 - 1626, 2026/01
Times Cited Count：0 Percentile：0.00(Chemistry, Multidisciplinary)Understanding the structural factors governing the metal ions selectivity of solvent extraction systems is crucial for developing advanced processes for partitioning and transmutation of high-level radioactive waste. Here, we systematically investigated the effect of alkyl side-chain branching in nitrilotriacetamide (NTAamide) extractants on the extraction of lanthanum (La) and neodymium (Nd), chosen as representative lanthanides. Four extractants having each eight carbon atoms as one of the amide chains with identical molecular weights but different degrees of alkyl branching were examined. Distribution ratios were measured as a function of HNO
concentration, and the local coordination structures of La and Nd were analyzed by extended X-ray absorption fine structure (EXAFS), while supramolecular aggregation in the organic phase was characterized by small-angle neutron scattering (SANS). EXAFS analysis revealed that the inner-sphere coordination environment of La and Nd was essentially unaffected by the degree of alkyl branching. In contrast, SANS results showed that extractants with fewer branched alkyl groups formed larger aggregates at low HNO concentrations, particularly in the case of Nd, where aggregation was found to facilitate extraction and prevent precipitation of poorly soluble complexes. These findings demonstrate that alkyl branching strongly influences supramolecular aggregation, which in turn governs extraction behavior. This work highlights the potential of nanoscale structural control as a new design concept for improving selectivity in lanthanide and actinide solvent extraction systems.
Hayashida, Shohei*; Wada, Takeshi*; Ishikado, Motoyuki*; Munakata, Koji*; Iida, Kazuki*; Kamazawa, Kazuya*; Kajimoto, Ryoichi; Inamura, Yasuhiro; Nakamura, Mitsutaka; Iwasa, Kazuaki*; et al.
High Pressure Research, 14 Pages, 2026/00
Nakamura, Yuki*; Kojima, Yoshihiro*; Yamashita, Takuya; Shimomura, Kenta; Mizokami, Shinya
Journal of Nuclear Science and Technology, 62(12), p.1226 - 1230, 2025/12
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Watanabe, Kaho; Nishiyama, Yutaka; Imahashi, Masaki; Taguchi, Yuji; Iitsuka, Yoshinobu; Ouchi, Takuya; Inoue, Shuichi; Kozawa, Takayuki; Nemoto, Takahiro; Sugaya, Takashi; et al.
JAEA-Testing 2025-001, 56 Pages, 2025/11
JAEA-Testing-2025-001.pdf:2.61MB
There is an emergency response team against 7 nuclear facilities (JRR-3 in Nuclear Science Research Institute, Tokai Reprocessing Plant (TRP) in Nuclear Fuel Cycle Engineering Laboratories, JMTR, HTTR and Joyo in Oarai Research and Development Institute, Prototype Fast Breeder Reactor Monju, Fugen Decommissioning Engineering Center) accidents of Japan Atomic Energy Agency (JAEA). The team is in Naraha Center for Remote Control Technology Development (NARREC). On site surveys which are about the situations and the access entering route of the 7 site emergencies were conducted by the team in 2021. And the results of the surveys made the team get two Spot (quadrupedal robots) in 2022. This is because the team thought using Spot gave operators the less exposure than using crawler robots which had been belonged to the team. After that it was confirmed that the Spot have the ability to respond to the emergency on the route of each facility in 2023. This report shows the results of the Spot's run function (= shooting videos, running oversteps, running up and down stairs, and so on) confirmation about 6 facilities (JRR-3, JMTR, HTTR, Joyo, Monju and Fugen).
Nakamura, Tatsuya; To, Kentaro; Kiyanagi, Ryoji; Ohara, Takashi; Hosoya, Takaaki; Tobe, Masahiro; Hishinuma, Yukio*; Ebine, Masumi; Sakasai, Kaoru
Journal of Physics; Conference Series, 3130(1), p.012002_1 - 012002_6, 2025/11
Upgrade of two two-dimensional scintillation neutron detectors for SENJU diffractometer at the Materials and Life science experimental Facility in the Japan Proton Accelerator Research Complex (J-PARC MLF) is underway. The current status of detector development for this project is briefly reviewed. The detector upgrade plan includes detector developments such as thin add-in detectors, high efficiency detectors to replace the original detectors, a large area detector placed under the sample vacuum tank, rectangular shaped one-bank detectors. All of these new detectors are developed based on 
Li:ZnS scintillators and WLS fibers. Recently, we developed a detector with a detection area four times larger than the original one (2 
2 size, 512 512 mm). Based on these results, work is now underway to further expand the detector area with rectangular shape of 1 3 (256 768 mm) and 2 3 (512 768 mm). The design and experimental results of the prototype detectors will be presented.
Ishigaki, Miho*; Tominaga, Nozomu*; Aoki, Wako*; Wanajo, Shinya*; Takiwaki, Tomoya*; Nakamura, Ko*; Iwamoto, Nobuyuki; Nomoto, Kenichi*; Kobayashi, Chiaki*
Astrophysical Journal, 992(2), p.215_1 - 215_17, 2025/10
Times Cited Count：2 Percentile：58.10(Astronomy & Astrophysics)Hasegawa, Kenta; Ambai, Hiromu; Takahatake, Yoko; Watanabe, So; Nakamura, Masahiro; Sano, Yuichi; Takeuchi, Masayuki
Progress in Nuclear Science and Technology (Internet), 8, p.248 - 251, 2025/09
Takito, Kiyotaka; Furuya, Osamu*; Nakamura, Izumi*; Okuda, Yukihiko
Proceedings of the ASME 2025 Pressure Vessels & Piping Conference (PVP2025) (Internet), 10 Pages, 2025/07
Natech stands for Natural Hazard Triggered Technological Accidents. The assessment of Natech and the implementation of appropriate measures have been highlighted by the accidents at the Fukushima Daiichi Nuclear Power Plant (NPP), and the gas tank fire caused by the earthquake in Japan. However, the data related to the structural failure with the system function is not sufficient to carry out the assessment of Natech in industrial plants, not only at NPPs. Therefore, the authors have investigated piping failure modes under seismic input to refer to the relationship between piping failure modes and assurance of piping function. Moreover, the authors have already performed the elbow and tee loading tests, the shaking table tests on a simple piping system to observe the referred failure modes of small-bore carbon steel piping. As a result, the authors have shown two of the referred modes are an elbow collapse and the axial crack growth of an elbow. In addition, it observed bifurcating into collapse mode and low cycle fatigue mode due to the relation between the dead load and input acceleration level. Consequently, to observe the failure modes under more realistic configurations, the authors fabricated a three-dimensional pipe specimen with multiple elbows and performed vibration tests using the vibration table in this study. The test specimen was designed to observe an elbow collapse or the axial crack growth on an elbow and under shaking table test. From the above, this paper reports the overview of this study and the results of the vibration tests. Especially, it shows the observed two different failure modes, axial plus circumferential crack and not just an elbow collapse but the overall fall including deformation of multiple elements under the shaking table tests.
-rays emitted from 
S(n,)
S reaction with polarized neutronsEndo, Shunsuke; Fujioka, Hiroyuki*; Ide, Ikuo*; Iinuma, Masataka*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Kameda, Kento*; Kawamura, Shiori*; Kimura, Atsushi; Kitaguchi, Masaaki*; et al.
EPJ Web of Conferences, 329, p.05003_1 - 05003_3, 2025/06
Times Cited Count：0 Percentile：0.00(Physics, Nuclear)no abstracts in English
Hf(n,)
Hf reaction measurementKawamura, Shiori*; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Kitaguchi, Masaaki*; Nakamura, Shoji; Okudaira, Takuya*; Rovira Leveroni, G.; Shimizu, Hirohiko*; et al.
EPJ Web of Conferences, 329, p.05002_1 - 05002_3, 2025/06
Times Cited Count：0 Percentile：0.00(Physics, Nuclear)no abstracts in English
in downwind East AsiaNozomu, Tsuchiya*; Ikemori, Fumikazu*; Kawasaki, Kazuo*; Yamada, Rena*; Hata, Mitsuhiko*; Furuuchi, Masami*; Iwamoto, Yoko*; Kaneyasu, Naoki*; Sadanaga, Yasuhiro*; Watanabe, Takahiro; et al.
Environmental Science & Technology, 59(21), p.10400 - 10410, 2025/05
Times Cited Count：1 Percentile：40.80(Engineering, Environmental)Black carbon (BC) is a typical primary aerosol emitted from combustion. While its co-existence with iron oxides (FeO
) has recently been reported, the extent of bias caused by FeO mixing to the BC observations is largely unknown. To identify the dominant FeO emission sources and associated overestimation of BC, magnetics properties of PM collected at a remote site in East Asia was investigated in combination with detailed isotopic and chemical analyses. Consequently, biomass burning events did not enhance aerosol magnetism as they did for the mass concentration of BC, whereas coal burning events coincided with periods of high magnetization. Therefore, magnetization/BC ratio is proposed as a highly selective indicator for identifying combustion sources (i.e. coal, oil or biomass burning).
Wada, Yuki*; Morimoto, Takeshi*; Wu, T.*; Wang, D.*; Kikuchi, Hiroshi*; Nakamura, Yoshitaka*; Yoshikawa, Eiichi*; Ushio, Tomoo*; Tsuchiya, Harufumi
Science Advances (Internet), 11(21), p.eads6906_1 - eads6906_10, 2025/05
Times Cited Count：1 Percentile：45.01(Multidisciplinary Sciences)
Sb
with a honeycomb networkAdachi, Tadashi*; Ogawa, Taiki*; Komiyama, Yota*; Sumura, Takuya*; Saito-Tsuboi, Yuki*; Takeuchi, Takaaki*; Mano, Kohei*; Manabe, Kaoru*; Kawabata, Koki*; Imazu, Tsuyoshi*; et al.
Physical Review B, 111(10), p.L100508_1 - L100508_6, 2025/03
Times Cited Count：1 Percentile：41.30(Materials Science, Multidisciplinary)Tanigawa, Masafumi; Seya, Kazuhito*; Asakawa, Naoya*; Hayashi, Hiroyuki*; Horigome, Kazushi; Mukai, Yasunobu; Kitao, Takahiko; Nakamura, Hironobu; Henzlova, D.*; Swinhoe, M. T.*; et al.
JAEA-Technology 2024-014, 63 Pages, 2025/02
JAEA-Technology-2024-014.pdf:3.02MB
The liquid waste treatment process generated sludge items at the plutonium conversion development facility. They are highly heterogeneous and contain large amounts of impurities (Na, Fe, Ni etc.). Therefore, the sludge items have very large sampling uncertainty and so the total measurement uncertainty is very large (approximately 24%). The plutonium scrap multiplicity counter (PSMC) measurement technique for sludge items was developed by joint research between the Japan Atomic Energy Agency (JAEA) and Los Alamos National Laboratory (LANL). The technical validity for sludge items using the PSMC was evaluated using various types of sample measurements and Monte Carlo N-Particle transport code calculations. The PSMC measurement parameters were found to be valid for use with sludge items and the validity of multiplicity analysis was confirmed and demonstrated through comparisons with standard MOX powder and a standard sludge. As a result, the PSMC measurement values were shown to be consistent and reasonable and the large amount of impurity (Fe, Ni etc.) did not impact the results. Therefore, the measurement uncertainty of the improved nuclear material accountancy (NMA) procedure by combined PSMC and high-resolution gamma spectrometry was shown to be 6.5%. In addition, an acceptance test was conducted using PSMC/HRGS and IAEA benchmark equipment. Measured Pu mass by both equipment agrees within the measurement uncertainty of each method, and so the validity for Pu mass measurement by PSMC/HRGS was confirmed. The above results confirm the applicability of PSMC/HRGS as an additional NMA method for sludge and a newly designed NDA procedure based on this study is applied to sludge for NMA in PCDF.
(Mg
Si)-phase in Al-Mg-Si-Ag alloyAhmed, A.*; Uttarasak, K.*; Tsuchiya, Taiki*; Lee, S.*; Nishimura, Katsuhiko*; Nunomura, Norio*; Ikeno, Susumu*; Malik, A.*; Shimizu, Kazuyuki*; Hirayama, Kyosuke*; et al.
Materials Today Communications (Internet), 43, p.111835_1 - 111835_10, 2025/02
Times Cited Count：2 Percentile：57.62(Materials Science, Multidisciplinary)Katsumura, Kosuke*; Takagi, Junichi*; Miyahara, Naoya*; Uchida, Shunsuke*; Koma, Yoshikazu; Karasawa, Hidetoshi; Miwa, Shuhei; Satou, Yukihiko; Nagai, Haruyasu; Kurata, Masaki; et al.
Nihon Genshiryoku Gakkai-Shi ATOMO
, 67(2), p.128 - 132, 2025/02
no abstracts in English
Nakamura, Satoshi; Ishii, Sho*; Kato, Hitoshi*; Ban, Yasutoshi; Hiruta, Kenta; Yoshida, Takuya; Uehara, Hiroyuki; Obata, Hiroki; Kimura, Yasuhiko; Takano, Masahide
Journal of Nuclear Science and Technology, 62(1), p.56 - 64, 2025/01
Times Cited Count：1 Percentile：23.55(Nuclear Science & Technology)A dissolution method for analyzing the elemental composition of fuel debris using the sodium peroxide (Na
O) fusion technique has been developed. Herein, two different types of simulated debris materials (such as solid solution of (Zr,RE)O and molten core-concrete interaction products (MCCI)) were taken. At various temperatures, these debris materials were subsequently fused with NaO in crucibles, which are made of different materials, such as Ni, AlO, Fe, and Zr. Then, the fused samples are dissolved in nitric acid. Furthermore, the effects of the experimental conditions on the elemental composition analysis were evaluated using inductively coupled plasma-atomic emission spectroscopy (ICP-AES), which suggested the use of a Ni crucible at 923 K as an optimum testing condition. The optimum testing condition was then applied to the demonstration tests with Three Mile Island unit-2 (TMI-2) debris in a shielded concrete cell, thereby achieving complete dissolution of the debris. The elemental composition of TMI-2 debris revealed by the proposed dissolution method has good reproducibility and has an insignificant contradiction in the mass balance of the sample. Therefore, this newly developed reproducible dissolution method can be effectively utilized in practical applications by dissolving fuel debris and estimating its elemental composition.
