Establishment of 3-D dose dispersion forecasting method and development of in-structure survey using the transparency difference of each line gamma-ray (Contract research); FY2022 Nuclear Energy Science & Technology and Human Resource Development Project

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.

Quantitative visualization of a radioactive plume with harmonizing gamma-ray imaging spectrometry and real-time atmospheric dispersion simulation based on 3D wind observation

Nagai, Haruyasu; Furuta, Yoshihiro*; Nakayama, Hiromasa; Satoh, Daiki

Journal of Nuclear Science and Technology, 60(11), p.1345 - 1360, 2023/11

https://doi.org/10.1080/00223131.2023.2197445

A novel monitoring method for the quantitative visualization of 3D distribution of a radioactive plume and source term estimation of released radionuclides is proposed and its feasibility is demonstrated by preliminary test. The proposed method is the combination of gamma-ray imaging spectroscopy with the Electron Tracking Compton Camera (ETCC) and real-time high-resolution atmospheric dispersion simulation based on 3D wind observation with Doppler lidar. The 3D distribution of a specific radionuclide in a target radioactive plume is inversely reconstructed from line gamma-ray images from each radionuclide by several ETCCs located around the target by harmonizing with the air concentration distribution pattern of the plume predicted by real-time atmospheric dispersion simulation. A prototype of the analysis method was developed, showing a sufficient performance in several test cases using hypothetical data generated by numerical simulations of atmospheric dispersion and radiation transport.

Visualization software for radioactive contamination based on Compton camera: COMRIS

Sato, Yuki; Minemoto, Kojiro*; Nemoto, Makoto*

Radiation Protection Dosimetry, 199(8-9), p.1021 - 1028, 2023/06

https://doi.org/10.1093/rpd/ncad106

Development of high-resolution imaging camera for alpha dust (Contract research); FY2021 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2022-065, 111 Pages, 2023/03

JAEA-Review-2022-065.pdf:6.8MB

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 FY2018, this report summarizes the research results of the "Development of high-resolution imaging camera for alpha dust" conducted from FY2018 to FY2021. Since the final year of this proposal was FY2021, the results for four fiscal years were summarized. The present study aims to develop a novel alpha-ray camera consisting of imaging and an energy spectrometer to find the alpha dust to reduce the risk of health damage in decommissioning. We have developed the camera with a position resolution of less than 10 m, and the measurement test for the energy spectra was operated using several alpha-ray sources with an unfolding method.

Estimation of radioactivity and dose equivalent rate by combining Compton imaging and Monte Carlo radiation transport code

Sato, Yuki

Applied Radiation and Isotopes, 185, p.110254_1 - 110254_7, 2022/07

https://doi.org/10.1016/j.apradiso.2022.110254

Noninvasive imaging of hollow structures and gas movement revealed the gas partial-pressure-gradient-driven long-distance gas movement in the aerenchyma along the leaf blade to submerged organs in rice

Yin, Y.-G.*; Mori, Yoshinao*; Suzui, Nobuo*; Kurita, Keisuke; Yamaguchi, Mitsutaka*; Miyoshi, Yuta*; Nagao, Yuto*; Ashikari, Motoyuki*; Nagai, Keisuke*; Kawachi, Naoki*

New Phytologist, 232(5), p.1974 - 1984, 2021/12

https://doi.org/10.1111/nph.17726

Rice () plants have porous or hollow organs consisting of aerenchyma, which is presumed to function as a low-resistance diffusion pathway for air to travel from the foliage above the water to submerged organs. However, gas movement in rice plants has yet to be visualized in real time. In this study involving partially submerged rice plants, the leaves emerging from the water were fed nitrogen-13-labeled nitrogen ([N]N) tracer gas, and the gas movement downward along the leaf blade, leaf sheath, and internode over time was monitored.

Visualization of radioactive substances using a freely moving gamma-ray imager based on Structure from Motion

Sato, Yuki; Minemoto, Kojiro*; Nemoto, Makoto*; Torii, Tatsuo

Journal of Nuclear Engineering and Radiation Science, 7(4), p.042003_1 - 042003_12, 2021/10

https://doi.org/10.1115/1.4048843

Non-invasive C-imaging revealed the spatiotemporal variability in the translocation of photosynthates into strawberry fruits in response to increasing daylight integrals at leaf surface

Miyoshi, Yuta*; Hidaka, Kota*; Yin, Y.-G.*; Suzui, Nobuo*; Kurita, Keisuke; Kawachi, Naoki*

Frontiers in Plant Science (Internet), 12, p.688887_1 - 688887_14, 2021/07

https://doi.org/10.3389/fpls.2021.688887

In this study, C-photosynthate translocation into strawberry fruits in individual plants was visualized non-invasively and repeatedly using a positron emission tracer imaging system (PETIS) to assess the spatiotemporal variability in the translocation dynamics in response to increasing daylight integrals. This is the first study to use C-radioisotopes to clarify the spatiotemporal variability in photosynthate translocation from source leaves to individual sink fruits in vivo in response to increasing daylight integrals at a high spatiotemporal resolution.

A Concept of mirror world for radioactive working environment by interactive fusion of radiation measurement in real space and radiation visualization in virtual space

Sato, Yuki

Physics Open (Internet), 7, p.100070_1 - 100070_8, 2021/05

https://doi.org/10.1016/j.physo.2021.100070

Neutron Bragg-edge transmission imaging for microstructure and residual strain in induction hardened gears

Su, Y. H.; Oikawa, Kenichi; Shinohara, Takenao; Kai, Tetsuya; Horino, Takashi*; Idohara, Osamu*; Misaka, Yoshitaka*; Tomota, Yo*

Scientific Reports (Internet), 11, p.4155_1 - 4155_14, 2021/02

https://doi.org/10.1038/s41598-021-83555-9