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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.
Collaborative Laboratories for Advanced Decommissioning Science; Kogakuin University*
JAEA-Review 2025-013, 111 Pages, 2025/10
JAEA-Review-2025-013.pdf:7.49MB
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 "Establishment of characterization method for small fuel debris using the world's first isotope micro imaging apparatus" conducted from FY2021 to FY2023. The present study aims to obtain, for the first time in the world, the important data necessary for clarifying the retrieval of small amounts of fuel debris, and to evaluate and examine them. The isotope microimaging apparatus (developed by Kogakuin University) introduced at the JAEA Fuel Monitoring Facility (FMF) can obtain local quantitative data such as isotope composition while processing cross-sections of radioactive micro-samples, which can be used to determine the properties of fuel debris. In FY2021, we improved the isotope microimaging apparatus introduced to the JAEA FMF to accommodate high radiation dose samples. In FY2022, we maintained the isotope microimaging apparatus at the JAEA FMF and succeeded in analyzing real particles containing uranium. In FY2023, we completed development to automate and remotely perform analysis routines using a prototype machine at Kogakuin University. At the JAEA FMF, although manual operations were involved, we succeeded in analyzing each Cs isotope from real particles by resonance ionization. In Nagoya University, we improved the RIMS apparatus to investigate the difference in electronic state caused by ion beam sputtering. And we succeeded in obtaining resonance ionization signals from neutral particles generated by ion beam sputtering. At the JAEA CLADS, they investigated the ionization scheme for important nuclides Nd and Gd. Those proposed ionization schemes were examined at Kogakuin University.
Karimi, V.*; Qvistgaard, C. H.*; Schmidt, S.*; Wolfertz, A.*; Parker, J. D.*; Kai, Tetsuya; Hayashida, Hirotoshi*; Shinohara, Takenao; Angelis, S. D.*; Tengattini, A.*; et al.
ACS Applied Materials & Interfaces, 17(36), p.50742 - 50752, 2025/08
Times Cited Count：0 Percentile：0.00Aoyama, Takahito; Ueno, Fumiyoshi; Sato, Tomonori; Kato, Chiaki; Sano, Naruto; Yamashita, Naoki; Otani, Kyohei; Igarashi, Takahiro
Annals of Nuclear Energy, 214, p.111229_1 - 111229_6, 2025/05
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Sato, Yuki
Radiation Protection Dosimetry, 201(7), p.490 - 500, 2025/05
Times Cited Count：0 Percentile：0.00(Environmental Sciences)Sato, Yuki; Terasaka, Yuta; Ichiba, Yuta*
Journal of Nuclear Science and Technology, 62(4), p.389 - 400, 2025/04
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Sato, Yuki; Minemoto, Kojiro*; Nemoto, Makoto*
Proceedings of Waste Management Conference 2025 (WM2025) (Internet), 9 Pages, 2025/03
Sato, Yuki; Kakuto, Takeshi*; Tanaka, Takayuki*; Shimano, Hiroyuki*
European Physical Journal; Special Topics, 10 Pages, 2025/00
Times Cited Count：0 Percentile：0.00(Physics, Multidisciplinary)Sato, Yuki; Minemoto, Kojiro*; Nemoto, Makoto*; Matsuura, Yasutaka*; Hayashi, Keisuke*
Proceedings of International Conference on Nuclear Decommissioning; Addressing the Past and Ensuring the Future 2023 (Internet), 4 Pages, 2025/00
The development of technology to visualize the distribution of radioactive substances at the decommissioning site of the Fukushima Daiichi Nuclear Power Station (FDNPS) is important for reducing worker exposure and developing a detailed work plan. Sato, one of the authors, developed an integrated Radiation Imaging System (iRIS) that combines a Simultaneous Localization and Mapping (SLAM) device, a Compton camera (a type of gamma-ray imager), and a survey meter, and have successfully produced a 3-D map of the working environment inside the FDNPS that visualizes the location of radioactive hot spots and the distribution of air dose rates. In addition, the authors are developing a system that enables users to experience the radiation environment of the FDNPS in virtual reality (VR) using the 3-D map visualizing such radiation information as input data. This VR system can use a commercially available portable VR head-mounted display, which not only displays the location of the radiation source in a virtual space, but also has the ability to calculate the exposure dose according to the working time. The development status of this VR system, which is expected to be effective in educating inexperienced workers and planning work, will be presented at the conference.
Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*
JAEA-Review 2024-016, 61 Pages, 2024/12
JAEA-Review-2024-016.pdf:2.88MB
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 FY2022. 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 a high-resolution imaging camera for alpha dust and high-dose rate monitor" conducted in FY2022. The present study aims to develop a high-resolution imaging camera for alpha dust and a high-dose rate monitor. To realize the high-resolution imaging camera for alpha dust, we have developed novel scintillation materials with emission bands of 500-800 nm. Moreover, we have prepared several materials for the camera and software. We have also developed novel scintillation materials with emission bands of 650-1,000 nm, and simulation studies have been conducted for the high-dose-rate monitor system consisting of optical fiber.
Materials Sciences Research Center
JAEA-Review 2024-037, 141 Pages, 2024/11
JAEA-Review-2024-037.pdf:13.08MB
Fifteen neutron beam experimental instruments managed by JAEA are installed in JRR-3 (Japan Research Reactor No.3) and are available for internal use including upgrading of instruments and for external users to produce various research results. This report summarizes the progress of internal application research and technical development such as upgrading of neutron beam instruments in the fiscal years 2021 and 2022 after the restart of operation.
Sato, Yuki
Applied Radiation and Isotopes, 212, p.111421_1 - 111421_8, 2024/10
Times Cited Count：1 Percentile：37.73(Chemistry, Inorganic & Nuclear)Collaborative Laboratories for Advanced Decommissioning Science; Kogakuin University*
JAEA-Review 2024-015, 99 Pages, 2024/09
JAEA-Review-2024-015.pdf:5.42MB
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 FY2022. 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 "Establishment of characterization method for small fuel debris using the world's first isotope micro imaging apparatus" conducted in FY2022. The present study aims to obtain, for the first time in the world, the important data necessary for clarifying the retrieval of small amounts of fuel debris, and to evaluate and examine them. SEM-EDS and TEM-EDS cannot be used for isotopic identification and analysis of Pu and B. On the other hand, bulk analysis such as ICP-MS lacks the information in a micro region.
Hasemi, Hiroyuki; Kai, Tetsuya
JAEA-Testing 2024-001, 39 Pages, 2024/08
JAEA-Testing-2024-001.pdf:1.4MB
RAIM is an analysis code that analyzes resonance absorption spectra measured at pulsed neutron sources such as the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC) to obtain information on nuclear densities and temperatures. By calculating the convolution of the pulse functions of neutron beam and the resonance capture function that is based on the nuclear cross section data, RAIM reproduces the resonance absorption spectrum measured by a pulsed neutron source. Then, RAIM determines the density and temperature of specific nuclides in a sample by performing spectral fitting on the resonance absorption spectrum data. In addition, RAIM is developed to facilitate the analysis of resonance imaging data by minimizing the number of parameters for calculation setup and by providing scripts for processing many resonance absorption spectra measured by a two-dimensional detector at once. This manual explains how to install RAIM on a computer and how to simulate resonance absorption spectra and fit them to measured data.
Sato, Yuki; Terasaka, Yuta; Oura, Masatoshi*
Journal of Nuclear Science and Technology, 61(7), p.856 - 870, 2024/07
Times Cited Count：9 Percentile：90.29(Nuclear Science & Technology)Collaborative Laboratories for Advanced Decommissioning Science; Kogakuin University*
JAEA-Review 2024-005, 79 Pages, 2024/06
JAEA-Review-2024-005.pdf:5.72MB
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 FY2021. 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 "Establishment of characterization method for small fuel debris using the world's first isotope micro imaging apparatus" conducted in FY2021. The present study aims to obtain, for the first time in the world, the important data necessary for clarifying the retrieval of small amounts of fuel debris, and to evaluate and examine them. SEM-EDS and TEM-EDS cannot be used for isotopic identification and analysis of Pu and B. On the other hand, bulk analysis such as ICP-MS lacks the information in a micro region.
Sato, Yuki; Kakuto, Takeshi*; Tanaka, Takayuki*; Shimano, Hiroyuki*; Morohashi, Yuko; Hatakeyama, Tomoyoshi*; Nakajima, Junsaku; Ishiyama, Masahiro
Nuclear Instruments and Methods in Physics Research A, 1063, p.169300_1 - 169300_7, 2024/06
Times Cited Count：3 Percentile：76.03(Instruments & Instrumentation)Collaborative Laboratories for Advanced Decommissioning Science; Kyoto University*
JAEA-Review 2023-028, 54 Pages, 2024/03
JAEA-Review-2023-028.pdf:3.81MB
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 FY2022. 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 FY2022. We realized an electron track detecting Compton camera (ETCC) that can measure 
-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.
Murakami, Kenta*; Arai, Taku*; Yamada, Koji*; Momma, Kensuke*; Tsuji, Takashi*; Nakagawa, Nobuyuki*; Onizawa, Kunio
Transactions of the 27th International Conference on Structural Mechanics in Reactor Technology (SMiRT 27) (Internet), 3 Pages, 2024/03
This paper studied the future vision of codes and standards in Japan by systematically comparing Japanese regulatory rules, standards, and industry guides related to long term operation with international safety standards, and confirmed that the Japanese standard system generally meets their recommendations. The recommendation for the future improvements of Japanese codes and standards were summarized into five items.
Sato, Yuki
Applied Radiation and Isotopes, 203, p.111083_1 - 111083_9, 2024/01
Times Cited Count：5 Percentile：72.91(Chemistry, Inorganic & Nuclear)