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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).
Ouchi, Takuya; Nagata, Hiroshi; Shinoda, Yuya; Yoshida, Hayato; Inoue, Shuichi; Chinone, Marina; Abe, Kazuyuki; Ide, Hiroshi; Watahiki, Shunsuke
JAEA-Technology 2025-006, 25 Pages, 2025/10
JAEA-Technology-2025-006.pdf:1.59MB
In the future, radioactive waste which generated from nuclear research facilities in Japan Atomic Energy Agency are planning to be buried for the near surface disposal. It is necessary to establish the method to evaluate the radioactivity concentrations of the radioactive wastes. Therefore, at the Oarai Nuclear Engineering Institute, in order to contribute to the study of methods for evaluating radioactivity concentrations of the radioactive wastes from nuclear research facilities, samples were taken from radioactive waste that are expected to be buried in the future and radiochemical analysis is used to obtain data on the radioactivity concentration of each nuclide contained in the radioactive waste. This report presents the concept of selecting sample collection targets and summarizes the sampling of radioactive materials conducted at the JMTR reactor facility in fiscal years 2023 and 2024 to obtain data on radioactivity concentrations.
Ikenoue, Tsubasa; Tani, Takashi*; Kawamura, Hideyuki; Sato, Yuhi*
Environmental Science & Technology, 7 Pages, 2025/09
Times Cited Count：0 Percentile：58.27Since 2023, ALPS-treated water containing tritium from the Fukushima Daiichi Nuclear Power Plant (1F) accident has been released into the ocean. Monitoring of seafood collected near the Fukushima coast has shown negligible increases in the tritium concentration. However, this monitoring has limitations, including delayed data release and a limited sample size. Therefore, a predictive estimation is necessary to assess the potential for high tritium accumulation in seafood. This study estimated tritium concentrations in Japanese flounder near the Fukushima coast using numerical simulations. The estimation combined an oceanic dispersion model for tritiated water (HTO) with a tritium transfer model for the marine food web. Tritium accumulation was evaluated as organically bound tritium (OBT), the long-retaining chemical form of tritium in organisms. First, the dispersion model's ability to reproduce HTO concentrations in seawater was validated using actual measurement data from the Fukushima coast, showing good agreement. Subsequently, the OBT concentrations in flounder were estimated under the hypothetical maximum release scenario of the treated water. The estimation suggested that even within 100 km of 1F, the maximum concentration of the OBT was comparable with natural levels of tritium in environmental waters. Additionally, the maximum concentration in the flounder remained at a negligible level for internal radiation exposure through consumption.
-butadiene) reinforced by carbon blackWatanabe, Yuki*; Kumagawa, Daiki*; Karitani, Shu*; Inoue, Tadashi*; Iwabuki, Hitoshi*; Nakanishi, Yohei*; Shibata, Motoki*; Motokawa, Ryuhei; Sugita, Tsuyoshi; Ueda, Yuki; et al.
Macromolecules, 58(16), p.8641 - 8648, 2025/08
Times Cited Count：0 Percentile：0.00Kokubun, Yuji; Hosomi, Kenji; Nagaoka, Mika; Seya, Natsumi; Inoue, Kazumi; Koike, Yuko; Uchiyama, Rei; Sasaki, Kazuki; Maehara, Yushi; Matsuo, Kazuki; et al.
JAEA-Review 2024-054, 168 Pages, 2025/03
JAEA-Review-2024-054.pdf:2.73MB
The Nuclear Fuel Cycle Engineering Laboratories conducts environmental radiation monitoring around the reprocessing plant in accordance with the "Safety Regulations for Reprocessing Plant of JAEA, Part IV: Environmental Monitoring". This report summarizes the results of environmental radiation monitoring conducted during the period from April 2023 to March 2024 and the results of dose calculations for the surrounding public due to the release of radioactive materials from the plant into the atmosphere and ocean. In the results of the above environmental radiation monitoring, several items were affected by radioactive materials emitted from the accident at the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company, Incorporated (changed to Tokyo Electric Power Holdings, Inc. on April 1, 2016), which occurred in March 2011. In addition, environmental monitoring plan, analysis and measurement methods, monitoring data and their chronological change, meteorological data after statistical processing, status of radioactive waste release and evaluation results of the data over the normal range are included as appendices.
Inoue, Yuki; Yamada, Junya; Hamaguchi, Takumi; Seya, Natsumi; Muto, Yasunobu; Nohara, Naofumi; Oishi, Tetsuya; Hashimoto, Makoto
JAEA-Data/Code 2024-017, 109 Pages, 2025/03
JAEA-Data-Code-2024-017.pdf:4.54MB
This report presents the results of environmental radiation monitoring at Oarai Nuclear Engineering Institute, JAEA for 10 years from 2011 to 2021 after the accident at the Fukushima Daiichi Nuclear Power Station. Database of monitoring results are included as an appendix. Environmental transfer parameters, deposition velocity, resuspension factor, concentration factor and distribution coefficient, are calculated as an Appendix.
Alam, M. M.*; Yamakita, Eri*; Inoue, Yuzuru*; Koarashi, Jun; Atarashi-Andoh, Mariko; Abe, Yukiko; Nakayama, Hiromasa; Mori, Yuki*; Hiradate, Shuntaro*
Soil Science and Plant Nutrition, 12 Pages, 2025/03
Inoue, Rintaro*; Oda, Takashi; Nakagawa, Hiroshi; Tominaga, Taiki*; Ikegami, Takahisa*; Konuma, Tsuyoshi*; Iwase, Hiroki*; Kawakita, Yukinobu; Sato, Mamoru*; Sugiyama, Masaaki*
Biophysical Journal, 124(3), p.540 - 548, 2025/02
Times Cited Count：2 Percentile：82.06(Biophysics)Inoue, Rintaro*; Nagata, Yuya*; Tominaga, Taiki*; Sato, Sota*; Kawakita, Yukinobu; Yamawaki, Tomonori*; Morishima, Ken*; Suginome, Michinori*; Sugiyama, Masaaki*
Journal of Chemical Physics, 161(5), p.054905_1 - 054905_8, 2024/08
shetta lakes in the Soya Coast region and their paleoenvironmental significance with glacial isostatic adjustment in East AntarcticaInoue, Genki*; Honda, Eisuke*; Ito, Keisuke*; Kang, I.*; Seto, Koji*; Tani, Yukinori*; Watanabe, Takahiro; Kashima, Kaoru*; Otani, Shuji*; Yamanaka, Toshiro*; et al.
Quaternary Science Reviews, 338, p.108822_1 - 108822_18, 2024/08
Times Cited Count：0 Percentile：0.00(Geography, Physical)We studied Holocene paleolimnological changes inferred from biomarkers and microscopic observation of microalgae and cyanobacteria in sediment cores from Rundvshetta lakes (Maruwanminami-ike and Maruwan o-ike) in the Soya Coast of East Antarctica, along with sedimentary facies and radiocarbon dating. Coastal marine environment: Maruwanminami-ike (147-72.5 cm, 5,010-2,590 cal BP) and Maruwan-oike (226-47.2 cm, 5,700-3,190 cal BP) were characterized by low biological production with the predominance of diatoms. Transition period of stratified brackish lake environment: Maruwanminami-ike (72.5-65.6 cm, 2,590-2,500 cal BP) and Maruwan-oike (47.2-28.8 cm, 3,190-2,890 cal BP) were characterized by stratified conditions with marine water overlain by freshwater, and a chemocline developed together with an anoxic layer in the bottom of photic zone.
Cs supply from rivers to coastal waters off Fukushima on the Cs behavior in seabed sedimentIkenoue, Tsubasa; Nakanishi, Takahiro; Shimadera, Hikari*; Kawamura, Hideyuki; Kondo, Akira*
E3S Web of Conferences (Internet), 530, p.02005_1 - 02005_10, 2024/05
The accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) caused a radioactive contamination in seabed sediment. The Cs supply from rivers could be an important process for the long-term behavior of Cs in seabed sediment. In this study, a ten-year simulation of the Cs behavior in seabed sediment was conducted using an oceanic dispersion model combined with a prediction model of Cs behavior in land and river. In the waters north of FDNPP, the simulation results suggested that the Cs supply from rivers had a great impact on the concentrations in coastal sediment due to the initial low concentrations in seabed sediment and the large supply of Cs from rivers. In the waters near FDNPP and south of FDNPP, the simulation results suggested that the impact of the Cs supply on the temporal variation of Cs concentration in coastal sediment was relatively small due to the large initial adsorption from seawater. Overall, these results indicated that Cs supply from rivers had an impact on the spatiotemporal distribution of Cs concentrations in seabed sediment on a decadal time scale and the impact was especially great in the waters north of FDNPP.
Ueji, Rintaro*; Gong, W.; Harjo, S.; Kawasaki, Takuro; Shibata, Akinobu*; Kimura, Yuji*; Inoue, Tadanobu*; Tsuchida, Noriyuki*
ISIJ International, 64(2), p.459 - 465, 2024/01
Times Cited Count：1 Percentile：32.08(Metallurgy & Metallurgical Engineering)Zhang, T.*; Oue, Daigo*; Tajima, Hiroyuki*; Matsuo, Mamoru; Liang, H.*
Physical Review B, 108(15), p.155303_1 - 155303_9, 2023/10
Times Cited Count：3 Percentile：27.64(Materials Science, Multidisciplinary)
Tamii, Atsushi*; Pellegri, L.*; S
derstrm, P.-A.*; Allard, D.*; Goriely, S.*; Inakura, Tsunenori*; Khan, E.*; Kido, Eiji*; Kimura, Masaaki*; Litvinova, E.*; et al.
European Physical Journal A, 59(9), p.208_1 - 208_21, 2023/09
Times Cited Count：10 Percentile：90.47(Physics, Nuclear)no abstracts in English
Toyoda, Shin*; Inoue, Kazuhiko*; Yamaguchi, Ichiro*; Hoshi, Masaharu*; Hirota, Seiko*; Oka, Toshitaka; Shimazaki, Tatsuya*; Mizuno, Hideyuki*; Tani, Atsushi*; Yasuda, Hiroshi*; et al.
Radiation Protection Dosimetry, 199(14), p.1557 - 1564, 2023/09
Times Cited Count：2 Percentile：33.46(Environmental Sciences)Interlaboratory comparison studies are important for radiation dosimetry in order to demonstrate how the technique is universally available. The set of standard samples are examined in each participating laboratory in the present study. After a set of standard samples together with the samples with unknown doses, which were prepared in the same laboratory as the standard samples, are measured at a participating laboratory, those samples are sent to another participating laboratory for next measurement. There is some small difference observed in the sensitivity (the slope of the dose response line) of the standard samples while the differences in the obtained doses for the samples with unknown doses are rather systematic, implying that the difference is mostly due to the samples but not to measurements.
Takabe, Yugo; Otsuka, Noriaki; Fuyushima, Takumi; Sayato, Natsuki; Inoue, Shuichi; Morita, Hisashi; Jaroszewicz, J.*; Migdal, M.*; Onuma, Yuichi; Tobita, Masahiro*; et al.
JAEA-Technology 2022-040, 45 Pages, 2023/03
JAEA-Technology-2022-040.pdf:6.61MB
Because of the decommission of the Japan Materials Testing Reactor (JMTR), the domestic neutron irradiation facility, which had played a central role in the development of innovative nuclear reactors and the development of technologies to further improve the safety, reliability, and efficiency of light water reactors, was lost. Therefore, it has become difficult to pass on the operation techniques of the irradiation test reactors and irradiation technologies, and to train human resources. In order to cope with these issues, we conducted a study on the implementation of irradiation tests using overseas reactors as neutron irradiation sites as an alternative method. Based on the "Arrangement between the National Centre for Nuclear Research and the Japan Atomic Energy Agency for Cooperation in Research and Development on Testing Reactor," the feasibility of conducting an irradiation test at the MARIA reactor (30 MW) owned by the National Centre for Nuclear Research (NCBJ) using the temperature control system, which is one of the JMTR irradiation technologies, was examined. As a result, it was found that the irradiation test was possible by modifying the ready-made capsule manufactured in accordance with the design and manufacturing standards of the JMTR. After the modification, a penetration test, an insulation continuity test, and an operation test in the range of room temperature to 300
C, which is the operating temperature of the capsule, were conducted and favorable results were obtained. We have completed the preparations prior to transport to the MARIA reactor.
Nagata, Shuhei*; Ogawa, Yusuke*; Suzuki, Satoru*; Inoue, Hiroyuki*; Watanabe, Yutaka*; Yamamoto, Masahiro*; Abe, Hiroshi*; Mitsui, Seiichiro
NUMO-TR-22-02, p.21 - 22, 2023/03
no abstracts in English
Tajima, Hiroyuki*; Oue, Daigo*; Matsuo, Mamoru; Kato, Takeo*
PNAS NEXUS (Internet), 2(3), p.pgad045_1 - pgad045_6, 2023/03
Nishikawa, Hidetsugu*; Takeuchi, Masayuki; Kitagaki, Toru; Inoue, Akinori*; Sato, Isamu*
Journal of Nuclear Science and Technology, 60(2), p.185 - 196, 2023/02
Times Cited Count：3 Percentile：34.65(Nuclear Science & Technology)Daido, Hiroyuki*; Yamada, Tomonori; Saruta, Koichi; Miyabe, Masabumi; Ito, Chikara; Shibata, Takuya; Inoue, Kaoru*; Terabayashi, Ryohei*; Hasegawa, Shuichi*
Physica Scripta, 98(3), p.035112_1 - 035112_22, 2023/02
Times Cited Count：1 Percentile：16.75(Physics, Multidisciplinary)Characterization of kW class quasi-continuous wave (a pulse duration of 10 ms) laser interaction with metal targets and those with metal oxide targets are presented in respect to the laser induced breakdown and the successive laser induced melting and evaporation coupled with a mechanical response followed by ejection of various kinds of particles and fragments. An experiment was performed using fiber lasers coupled with a high-speed camera to observe dynamics of the interaction. Ejected fine particles were collected using a cascade impactor and a home-made collector and were observed with electron microscopes. Shapes of irradiation marks were observed with a digital optical microscope. We also measured total ejected mass from a target. The experimental results reveal that firstly the laser threshold intensity of the interaction with the metal target was lower and more stable than those with the metal oxide targets. Secondly, in the stainless steel targets, the dynamics of molten layer created by thermal conduction from the laser heated thin layer and successive particle ejection with less mechanical response by the adjacent solid layer are dominant processes, while in the metal oxide targets, the fracturing in the relatively deeper interaction region coupled with brittle material response having relatively large laser shot to shot fluctuation appears to play a significant role in addition to the laser induced melting.
