Development of a laser deflection-type ultrasonic wideband 3D imaging system for in-vessel visualization in high-radiation and non-visible environments (Contract research); FY2024 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Institute of Science Tokyo*

JAEA-Review 2026-007, 65 Pages, 2026/06

JAEA-Review-2026-007.pdf:4.67MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), has been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") from FY2019. 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 FY2024, this report summarizes the research results of the "Development of a laser deflection-type ultrasonic wideband 3D imaging system for in-vessel visualization in high-radiation and non-visible environments" conducted in FY2024. The present study aims to maximize the safety of debris-cutting operations by enabling visualization of in-vessel structures, fuel debris shapes, and scattered particles at distances on the order of several meters, even under dusty and turbid water conditions during work. To achieve this, a compact and portable ultrasonic device suitable for mounting on robots and manipulator arms is employed to develop a laser deflection-type ultrasonic wideband 3D imaging system. In FY2024, the project carried out imaging performance evaluation and studies for the advancement and acceleration of the ultrasonic imaging system, numerical simulations, prototyping and full-scale verification of the system, radiation resistance tests, construction of a submillimeter ultrasonic ranging system, application of the ultrasonic sub-millimeter ranging system to LIBS, as well as battery-powered remote operation of the measurement system. These outcomes are summarized in this report.

Neutron capture cross-section measurements at TC-Pn in KUR for tungsten among nuclides in decommissioning

Nakamura, Shoji; Shibahara, Yuji*; Kimura, Atsushi; Endo, Shunsuke; Rovira Leveroni, G.

KURNS Progress Report 2025, P. 101, 2026/06

https://adm.rri.kyoto-u.ac.jp/pub/progressrep2/

no abstracts in English

Proceedings of the 10th "Conference for R&D Initiative on Nuclear Decommissioning Technology by the Next Generation"

Usami, Hiroshi; Ito, Rintaro; Sanada, Yukihisa

JAEA-Review 2025-050, 57 Pages, 2026/02

JAEA-Review-2025-050.pdf:17.19MB

The decommissioning of the TEPCO's Fukushima Daiichi Nuclear Power Station is a long-term project, and the training of young engineers and researchers who will be responsible for future decommissioning is a necessary and urgent task. Since 2016, Collaborative Laboratories for Advanced Decommissioning Science has been continuously organizing "Conference for R&D Initiative on Nuclear Decommissioning Technology by the Next Generation (NDEC)" for students who are engaged in research activities for decommissioning. NDEC is a forum for students to present their research for the purpose of human resource development and networking among young researchers, and to increase their motivation for decommissioning research. NDEC-10 was held at "Plaza-Bansho" in Tsuruga-City, Fukui Prefecture, from February 26 - 27, 2025. This proceeding compiles the contents of report papers in the conference.

Development of a prototype shielding-free radiation-resistant diamond neutron measurement system (Contract research); FY2023 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*

JAEA-Review 2025-028, 66 Pages, 2025/11

JAEA-Review-2025-028.pdf:3.59MB

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 (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 FY2023, this report summarizes the research results of the "Development of a prototype shielding-free radiation-resistant diamond neutron measurement system" conducted in FY2023. The present study aims to develop a prototype of a shielding-free neutron measurement system for 1F. The system consists of diamond neutron detectors and radiation-resistant silicon integrated circuits, and has radiation resistance of more than 10 MGy and 4 MGy, respectively, at the component level in terms of integrated dose, and has a track record of stable operation under -ray dose rate environment of 1.5 kGy/h. Future applications are expected to include neutron detectors for debris investigation, criticality proximity monitoring monitors, and neutron detectors for dry tube investigation in pressure vessels. In this development, a prototype consisting of 100 diamond detector elements of 5 mm square will be developed to obtain system construction technology and to evaluate system performance. In addition, a subcriticality evaluation method will be developed. This development will lead to the completion of system development, development of the actual system in collaboration with the manufacturer, and introduction of the system into 1F decommissioning project.

Research on radioactive aerosol control and decontamination at Fukushima Daiichi Nuclear Power Station Decommissioning (Contract research); FY2023 Nuclear Energy Science & Technology and Human Resource Development Project

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.

Development of robot technology that contributes to the decommissioning of the 1F NPS; Development of robotics for harsh environments in 1F decommissioning utilizing DX at the JAEA Naraha Center for Remote Control Technology Development (NARREC)

Tagawa, Akihiro

Nihon Genshiryoku Gakkai-Shi ATOMO, 67(9), p.510 - 513, 2025/09

https://doi.org/10.3327/jaesjb.67.9_510

no abstracts in English

Measurements of neutron capture cross-section for nuclides of interest in decommissioning (III); Er(n,)Er and Hf(n,)Hf reactions

Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Rovira Leveroni, G.; Kimura, Atsushi

Journal of Nuclear Science and Technology, 62(7), p.617 - 630, 2025/07

https://doi.org/10.1080/00223131.2025.2457589

Development of HCl-free solid-phase extraction combined with ICP-MS/MS for rapid assessment of difficult-to-measure radionuclides, 3; Measurement of Se concentration in concrete rubble

Banjarnahor, I. M.; Do, V.-K.; Furuse, Takahiro; Ota, Yuki; Tanaka, Kosuke

Journal of Radioanalytical and Nuclear Chemistry, 334(7), p.4997 - 5006, 2025/05

https://doi.org/10.1007/s10967-025-10143-w

Assessment report of research and development activities in FY2023; Activity "Implementation and technological development of decommissioning of nuclear facilities" and "Implementation and technological development of radioactive waste processing" (In-advance evaluation)

Nuclear Backend Technology Development

JAEA-Evaluation 2024-002, 86 Pages, 2025/03

JAEA-Evaluation-2024-002.pdf:8.29MB

Japan Atomic Energy Agency (hereinafter referred to as "JAEA") consulted the "Evaluation Committee on Research and Development Activities for Decommissioning" (hereinafter referred to as "Committee") about the in-advance evaluation of research themes which had started after FY2021 of R&D plan for the 4th medium- and long-term objectives period concerning "Decommissioning of nuclear facilities and development of technologies for the treatment of related radioactive waste" project in accordance with the "Guideline for evaluation of government R&D activities". In response, the Committee evaluated to the evaluation points of view made by JAEA.

Measurements of neutron capture cross-section for nuclides of interest in decommissioning (II); Fe(n,)Fe

Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Rovira Leveroni, G.; Kimura, Atsushi

Journal of Nuclear Science and Technology, 62(3), p.300 - 307, 2025/03

https://doi.org/10.1080/00223131.2024.2427244