Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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)Ji, Y.-Y.*; Joung, S.*; Ji, W.*; Ochi, Kotaro; Sasaki, Miyuki; Sanada, Yukihisa
Journal of Radiological Protection, 45(4), p.042501_1 - 042501_11, 2025/12
This study reports the development and field validation of KAERI's UAV-based gamma-ray spectrometry system equipped with LaBr
(Ce) detectors. Joint surveys with JAEA near Fukushima Daiichi Nuclear Power Plant (FDNPP) showed reliable dose rate estimation after applying altitude based attenuation correction, through discrepancies occurred in sloped terrain. Incorporating terrain data is recommended to enhance accuracy for emergency response applications.
Watanabe, Kaho; Nishiyama, Yutaka; Kakuta, Masakatsu*; Hayasaka, Toshiro*
JAEA-Testing 2025-003, 52 Pages, 2025/11
JAEA-Testing-2025-003.pdf:5.17MB
There is an emergency response team against nuclear facilities accidents of Japan Atomic Energy Agency (JAEA). The team is managed by the Maintenance and Operation Section for Remote Control Equipment. One of the important tasks of the team is purchasing remote-control robots, the quadrupedal robots (called Spot), were purchased in 2022 and 2023 to prepare for the nuclear disaster in JAEA. This report shows the remote-control manual for the quadrupedal robots (Spot), and it is focused on the necessary operations for the team.
Hotoku, Shinobu; Ban, Yasutoshi; Konda, Miki; Kitatsuji, Yoshihiro
JAEA-Technology 2025-009, 33 Pages, 2025/11
JAEA-Technology-2025-009.pdf:1.9MB
High-level liquid waste (HLLW) produced from reprocessing of spent nuclear fuels contains heat generating nuclides such as Sr-90, Y-90, Cs-137, Ba-137m, and Am-241. Separation and recovery of these nuclides lead to reduce the volume and toxicity of high-level waste. Furthermore, the recovered nuclides and elements could be utilized as resources after purification. In this test, Sr separation by extraction chromatography using Sr resin and Pb resin, Cs separation by co-precipitation using ammonium phosphomolybdate (AMP), and Am separation by solvent extraction using alkyl diamideamine (ADAAM) were carried out, cold tests were performed for the separation of Cs and Sr in a nitric acid solution. Based on the results, hot tests were performed using dissolution solutions of spent fuel at the Nuclear Fuel Cycle Safety Engineering Research Facility (NUCEF), and each component contained in the separated solution was analyzed. In the Sr separation by extraction chromatography, most of Sr was separated from other elements using 8 mol/L nitric acid for absorption and 0.02 mol/L nitric acid for elution. In the separation of Cs, more than 99.9% of Cs was selectively co-precipitated by adding AMP to the HLLW, in which nitric acid concentration was adjusted to 3.1 mol/L. In solvent extraction of Am by ADAAM, 81.4% of Am-241 was recovered by a single stage batch experiment. Since Sr, Cs, and Am were properly separated and recovered from HLLW, the effectiveness of the present separation method was successfully demonstrated.
Irisawa, Eriko; Kato, Chiaki
Corrosion Science, 256, p.113173_1 - 113173_16, 2025/11
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)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.
Kawasaki, Nobuchika
JAEA-Review 2025-043, 74 Pages, 2025/10
JAEA-Review-2025-043.pdf:2.45MB
Russia is one of the most advanced countries in the civilian use of nuclear energy. However, understanding the internal mechanisms of its nuclear program remains difficult due to various reasons. Therefore, this study presents a historical overview of Russia's nuclear energy utilization, fuel supply, fuel manufacturing capabilities, and concepts regarding reprocessing and the nuclear fuel cycle. From this overview, insights have been extracted and analyzed. These insights are then organized under two strategic perspectives: "Strategic diversity and continuity in developments and demonstrations" and "Diversity in utilizations and deployments," with considerations of implications for Japan, as below. Russia's nuclear energy policy strategically utilizes a variety of reactor types and fuel cycle technologies to expand nuclear power generation both domestically and internationally. Currently, nuclear power, centered on light-water reactors (VVER series), accounts for about 20% of Russia's electricity supply, and there are plans to increase this share to 25% by 2045. A wide range of reactors, from large-scale to medium and small modular reactors, are being constructed in Russia. Russia is also actively developing fast reactor technologies, and focusing on the reprocessing and recycling of spent fuel. Internationally, VVER-1200 reactors are under construction in several countries, and cooperation with China is deepening in the field of fast reactors. Notably, Russia offers an integrated, or selectively customizable, package of nuclear technology services on the international stage. These include not only reactor deployment, but also fuel supply, reprocessing, waste management, and even the provision of radioisotopes. Rather than simply exporting products or technology, Russia fosters long-term relationships and trust by flexibly responding to the conditions and needs of partner countries. For this reason, Russia promotes the technology developments in advance within the country in areas anticipated for future overseas deployment. It carefully selects target technologies and services and systematically rolls them out. This flexible strategy, combining "technological diversity" and "strategic consistency", enables cooperation with countries across various geopolitical contexts. For Japan, this strategic approach offers valuable lessons on how to engage in comprehensive international nuclear cooperation, not merely through technology exports, but through integrated approaches that encompass the entire fuel cycle, and by combining elements such as fast reactors and RI supply.
Collaborative Laboratories for Advanced Decommissioning Science; Yokohama National University*
JAEA-Review 2025-025, 90 Pages, 2025/10
JAEA-Review-2025-025.pdf:5.59MB
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 passive wireless communication systems operatable under inferior-wireless environment with obstacles" conducted in FY2023. This study aims to develop a wireless communication system for obstacle-dense environments by designing base stations, sensor nodes (SN), positioning algorithms, and wireless area formation methods for electromagnetic wave-shielded regions. Key outcomes are as follows: For direction-finding with high-performance antennas, triangulation positioning accuracy was evaluated, and a sensor information demodulation system was built. SNs with frequency-scanning analog and frequency-fixed digital methods achieved communication distances of 6-8 meters and wireless charging of 1-2 V in 3-15 minutes at 6 meters. Diode characteristics remained unchanged after 1,000 Gy radiation. Positioning algorithms using multipath tomography were validated with a high-resolution measurement system in the lab. Simulations with reactor building CAD diagrams optimized node numbers and arrangements. Wireless coverage in electromagnetic wave-shielded regions was tested using a composite antenna (patch array and waveguide), achieving a range of approximately 1.5 meters.
-contamination visualization (Contract research); FY2023 Nuclear Energy Science & Technology and Human Resource Development ProjectCollaborative 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.
Collaborative Laboratories for Advanced Decommissioning Science; Kyoto University*
JAEA-Review 2025-020, 74 Pages, 2025/10
JAEA-Review-2025-020.pdf:5.85MB
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 FY2022, this report summarizes the research results of the "Establishment of 3-D dose dispersion forecasting method and development of in-structure survey using the transparency difference of each line gamma-ray" conducted in FY2023. We realized an electron track detecting Compton camera (ETCC) that can measure gamma-ray images (linear images) with the bijective projection. In the "Quantitative analysis of radioactivity distribution by imaging of high radiation field environment using gamma-ray imaging spectroscopy" (hereinafter referred to as the previous project) adopted in FY2018, the 1 km square area including the reactor buildings was imaged at once. In FY2021, 3-D dosimetry in the reactor building of the Institute for Integrated Radiation and Nuclear Science was carried out, and 3-D imaging of gamma-rays was successfully obtained. This project will build on the results of the previous project to develop a practical 3-D contaminant dispersion detection and prediction system for sub-mSv/h environments. In addition, a 3-D radiographic Cs distribution measurement method inside the reactor building using highly penetrating 
Cs gamma-rays will be developed. In FY2023, we fabricated a lightweight and highly effective shielding specifically for the TPC of ETCC based on simulations. In addition, by conducting calibration experiments at the FRS facility, we were also able to repair bugs in the signal processing circuit. Those meticulous advance preparations enabled us to successfully conduct a 3-D experiment within 1F in March 2024.
Wada, Yuki; Shibamoto, Yasuteru; Hibiki, Takashi*
International Journal of Heat and Mass Transfer, 249, p.127219_1 - 127219_16, 2025/10
Times Cited Count：0 Percentile：0.00(Thermodynamics)Jeong, S. G.*; Kwon, J.*; Kim, E. S.*; Prasad, K.*; Harjo, S.; Gong, W.; Kawasaki, Takuro; Estrin, Y.*; Bouaziz, O.*; Hong, S. I.*; et al.
Materials Science & Engineering A, 942, p.148712_1 - 148712_11, 2025/10
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)Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*
JAEA-Review 2025-015, 73 Pages, 2025/09
JAEA-Review-2025-015.pdf:5.9MB
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 FY2021, this report summarizes the research results of the "Research on radioactive aerosol control and decontamination at Fukushima Daiichi Nuclear Power Station decommissioning" conducted from FY2021 to FY2023. The present study aims to develop a safe laser decontamination system that integrates advanced particle detection and characterization systems with aerosol dispersion control, in collaboration with UK researchers. For aerosol dispersion control, new containment methods ranging from simple mechanical containment hoods to optical laser shields are jointly investigated. The Japanese team will develop a radioactive dispersion control method based on the use of water mist and water spray to reduce radiation risks during laser cutting and decontamination applications. Based on data on aerosol particles provided by the UK team, the potential to enhance aerosol scrubbing efficiency will be explored. Additionally, the effect of charge enhancement will be evaluated. The UK team will develop laser-based aerosol containment methods and conducting experiments to improve the condensation of aerosol particles and mist in spray scrubbing. The development of aerosol removal technologies and strategies will be carried out through comprehensive experimental and computational studies. Experiments will be conducted at UTARTS facility to verify simultaneous operations such as laser decontamination, cutting, and spray operations. Aerosol measurements will also be performed to obtain high spatial resolution data that can better validate CFD models. In the final year, mock-up tests will be conducted to verify the system's operation and decontamination performance at full scale, evaluating the decontamination system developed through this research.
Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*
JAEA-Review 2025-014, 86 Pages, 2025/09
JAEA-Review-2025-014.pdf:9.38MB
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 FY2021, this report summarizes the research results of the "Novel mechanical manipulator for efficient fuel debris retrieval" conducted from FY2021 to FY2023. The present study aims to the development of a collision-tolerant robotic manipulator with the mechanical variable impedance actuators in an unknown environment. Another research target is the system architecture of an artificial intelligence-based control method for efficient exploration and decommissioning. In addition to conducting an investigation in the area deep inside the aperture, which has been difficult with conventional investigations, we aim to recover pebble-shaped fuel debris at the bottom of the pedestal using a gripper at the tip of the manipulator. We will establish a manipulator mechanism and remote-control system to cope with the environmental constraints inside the pedestal. This year focused on developing a manipulator navigation algorithm, evaluating control performance, and conducting on-site scenario demonstration experiments. Studies included building a driving model, designing a control algorithm, and assessing manipulator control performance, with comparisons to simulation models. Demonstration experiments were conducted at facilities like the JAEA Naraha Center for Remote Control Technology Development. The research was promoted in close collaboration with the UK team and external advisors, including bi-weekly meetings. At the end of the fiscal year, an oral presentation introducing the project was given at an international workshop organized by the University of Tokyo and Technical University of Munich (TUM).
Fukushima Research and Engineering Institute*
JAEA-Evaluation 2025-001, 23 Pages, 2025/09
JAEA-Evaluation-2025-001.pdf:0.72MB
JAEA-Evaluation-2025-001-appendix(CD-ROM).zip:185.38MB
Japan Atomic Energy Agency (hereinafter referred to as "JAEA") consulted an assessment committee, "Evaluation Committee of Research and Development related to the Accident at TEPCO's Fukushima Daiichi Nuclear Power Station" (hereinafter referred to as "Committee") for ex-ante evaluations of "Research and Development Related to the Accident at TEPCO's Fukushima Daiichi Nuclear Power Station" in accordance with "General Guideline for the Evaluation of Government Research and Development (R&D) Activities" by Cabinet Office, Government of Japan, "Guideline for Evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology" and "Regulation on Conduct for Evaluation of R&D Activities" by JAEA. Based on a request from JAEA, the committee conducted a post-evaluation of research and development activities in the fourth phase (April 2022 to March 2029) of the medium-term research plan. This report summarizes the results of the assessment by the Committee.
Shamoto, Shinichi; Shin, K.*; Akatsu, Mitsuhiro*; Imai, Masaki; Ueta, Daichi*; Yokoo, Tetsuya*; Nemoto, Yuichi*; Hassan, A. M. A.*; Chang, L.-J.*; Ieda, Junichi; et al.
Applied Physics Letters, 127(13), p.132403_1 - 132403_5, 2025/09
Yamaguchi, 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.
Otani, Kyohei; Igarashi, Takahiro
Journal of the Electrochemical Society, 172(9), p.091503_1 - 091503_8, 2025/09
Times Cited Count：0 Percentile：0.00Watanabe, 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：0 Percentile：0.00The 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.
