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Kaminaga, Kiichi*; Hirose, Eri; 5 of others*
Journal of Radiation Research (Internet), 66(3), p.318 - 328, 2025/05
Times Cited Count:0 Percentile:0.00(Biology)Hidaka, Hiroyuki*; Yanagiya, Shun*; Onodera, Shintaro*; Yanagisawa, Tatsuya*; Amitsuka, Hiroshi*; Tanida, Hiroshi*; Ishitobi, Takayuki
Journal of the Physical Society of Japan, 94(3), p.034706_1 - 034706_9, 2025/03
Times Cited Count:0 Percentile:0.00(Physics, Multidisciplinary)Horiuchi, Hiroto*; Araki, Yasufumi; Wakabayashi, Yuki*; Ieda, Junichi; Yamanouchi, Michihiko*; 7 of others*
Advanced Materials, p.2416091_1 - 2416091_9, 2025/00
Times Cited Count:0 Percentile:0.00(Chemistry, Multidisciplinary)Toyama, Takeshi*; Tanno, Takashi; Yano, Yasuhide; Inoue, Koji*; Nagai, Yasuyoshi*; Otsuka, Satoshi; Miyazawa, Takeshi; Mitsuhara, Masatoshi*; Nakashima, Hideharu*; Onuma, Masato*; et al.
Journal of Nuclear Materials, 599, p.155252_1 - 155252_14, 2024/10
Times Cited Count:0 Percentile:0.00(Materials Science, Multidisciplinary)We investigated the stability of oxide nano particles in oxide dispersion-strengthened (ODS) steel, which is a promising candidate material for next-generation reactors, under neutron irradiation at high temperature to high doses. MA957, a 14Cr-ODS steel, was irradiated with Joyo in Japan Atomic Energy Agency under irradiation conditions of 130 dpa at 502C, 154 dpa at 589
C, and 158 dpa at 709
C. Three-dimensional atom probe (3D-AP) and transmission electron microscope (TEM) observation were performed to characterize the oxide particles in the ODS steels. A high number density of Y-Ti-O particle was observed in the unirradiated and irradiated samples. Almost no change in the morphology of the oxide particles, i.e. average diameter, number density, and chemical composition, has been observed in the samples irradiated to 130 dpa at 502
C and to 154 dpa at 589
C. A slight decrease in number density was observed in the sample irradiated to 158 dpa at 709
CC. The hardness of any of the irradiated samples was almost unchanged from that of the unirradiated sample. It was revealed that the oxide particles existed stable, and the strength of the material was sufficiently maintained even after being neutron irradiated to high dose of
160 dpa at high temperature up to 700
C. A part of this study includes the results of MEXT Innovative Nuclear Research and Development Program Grant Number JPMXD0219214482.
Ono, Ayako; Sakashita, Hiroto*; Yamashita, Susumu; Suzuki, Takayuki*; Yoshida, Hiroyuki
Mechanical Engineering Journal (Internet), 11(4), p.24-00188_1 - 24-00188_12, 2024/07
Japan Atomic Energy Agency (JAEA) is developing the evaluation method for a two-phase flow in the reactor core using simulation codes based on the Volume Of Fluid (VOF) method. JAEA started developing a Simplified Boiling Model (SBM) for the large-scale two-phase flow in the fuel assemblies. In the SBM, the motion and growth equations of the bubble are solved to obtain their diameter and time length at the detachment, of which size scale is within/around the calculation grid size of the numerical simulation. JUPITER calculates the bubble behavior with a scale of more than several m. In this study, the convection boiling on a vertical heating surface is simulated using the developed SBM. The comparison between the simulation and experimental results showed good reproducibility of the heat flux and velocity dependency on the passage period of the bubble.
Lan, Z.*; Arikawa, Yasunobu*; Mirfayzi, S. R.*; Morace, A.*; Hayakawa, Takehito*; Sato, Hirotaka*; Kamiyama, Takashi*; Wei, T.*; Tatsumi, Yuta*; Koizumi, Mitsuo; et al.
Nature Communications (Internet), 15, p.5365_1 - 5365_7, 2024/07
Times Cited Count:5 Percentile:75.95(Multidisciplinary Sciences)Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*
JAEA-Review 2024-006, 54 Pages, 2024/06
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 "Development of elemental technologies of hand-foot-cloth monitors for -contamination visualization" conducted in FY2022. The present study aims to develop hand-foot-monitors for
-contamination visualization and cloth monitors for
/
-contamination visualization consisting of a portable phoswich detector for measuring
/
-contamination distribution and energy to ensure the safety and security of workers involved in the decommissioning project of the 1F. The possibility of practical application of new scintillator materials and devices was examined with the goal of developing such new instruments.
Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*
JAEA-Review 2023-027, 126 Pages, 2024/03
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 FY2020, this report summarizes the research results of the "Study on rational treatment/disposal of contaminated concrete waste considering leaching alteration" conducted from FY2020 to FY2022. The present study aims to understand migration behaviors of radionuclides in relation to the properties of concrete altered by leaching, to develop migration model of radionuclides, and to evaluate waste management scenarios, focusing on underground concrete structures in contact with contaminated water.
Yamada, Kazuo*; Hokora, Hideyuki*; Maruyama, Ippei*; Aihara, Haruka; Tomita, Sayuri*; Tojo, Yasumasa*; Shibuya, Kazutoshi*; Hosokawa, Yoshifumi*; Igarashi, Go*; Koma, Yoshikazu
Proceedings of Waste Management Symposia 2024 (WM2024) (Internet), 7 Pages, 2024/03
Saito, Yuki*; Ishiwata, Tobimaru*; Horiuchi, Misato*; Nishiki, Yuto*; Kikuchi, Ryosuke*; Otake, Tsubasa*; Kawakita, Ryohei; Takayama, Yusuke; Mitsui, Seiichiro; Sato, Tsutomu*
Shigen, Sozai Koenshu (Internet), 11(1), 7 Pages, 2024/03
no abstracts in English
Sawa, Kazuhiro*; Haseda, Masaya*; Aihara, Jun
Nihon Kikai Gakkai Rombunshu (Internet), 89(921), p.22-00314_1 - 22-00314_6, 2023/05
In high temperature gas-cooled reactors (HTGRs), Tri-isotropic (TRISO)-coated fuel particles are employed as fuel. In the high burnup coated fuel particle, stress due to fission gas pressure and irradiation-induced pyrolytic carbon (PyC) shrinkage is introduced into the coating layers and consequently the stress could cause failure of coating layers under high burnup irradiation condition. A failure model has developed to predict failure fraction of TRISO-coated particle under high burnup irradiation. In the model, failure probability is strongly dependent on the irradiation characteristics of PyC. This paper describes the outline of the failure model and evaluation result of high burnup fuel irradiation experiment by the model.
Mitsuhara, Masatoshi*; Kurino, Koichi*; Yano, Yasuhide; Otsuka, Satoshi; Toyama, Takeshi*; Onuma, Masato*; Nakashima, Hideharu*
Tetsu To Hagane, 109(3), p.189 - 200, 2023/03
Times Cited Count:1 Percentile:11.66(Metallurgy & Metallurgical Engineering)Oxide Dispersion Strengthened (ODS) ferritic steel, a candidate material for fast reactor fuel cladding, has low thermal expansion, good thermal conductivity, and excellent resistance to irradiation damage and high temperature strength. The origin of the excellent high-temperature strength lies in the dispersion of fine oxides. In this study, creep tests at 700 or 750C, which are close to the operating temperatures of fast reactors, and high-temperature tensile tests at 900 to 1350
C, which simulate accident conditions, were conducted on 9Cr ODS ferritic steels, M11 and MP23, and 12Cr ODS ferritic steel, F14, to confirm the growth behavior of oxides. In the M11 and F14 creep test samples, there was little oxide growth or decrease in number density from the initial state, indicating that dispersion strengthening by oxides was effective during deformation. After creep deformation of F14, the development of dislocation substructures such as dislocation walls and subgrain boundaries was hardly observed, and mobile dislocations were homogeneously distributed in the grains. The dislocation density increased with increasing stress during the creep test. In the high-temperature ring tensile tests of MP23 and F14, the strength of both steels decreased at higher temperatures. In MP23, elongation decreased with increasing test temperature from 900 to 1100
C, but increased at 1200
C, decreased drastically at 1250
C, and increased again at 1300
C. In F14, elongation decreased with increasing temperature. It was inferred that the formation of the
-ferrite phase was responsible for this complex change in mechanical properties of MP23 from 1200 to 1300
C.
Yamada, Kazuo*; Tojo, Yasumasa*; Aihara, Haruka; Tomita, Sayuri*; Hokora, Hideyuki*; Shibuya, Kazutoshi*; Koma, Yoshikazu; Igarashi, Go*; Hosokawa, Yoshifumi*; Maruyama, Ippei*
Proceedings of Waste Management Symposia 2023 (WM2023) (Internet), 12 Pages, 2023/02
Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*
JAEA-Review 2022-050, 116 Pages, 2023/01
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 (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 FY2019, this report summarizes the research results of the "Safe, efficient cementation of challenging radioactive wastes using alkali activated materials with high-flowability and high-anion retention capacity" conducted from FY2019 to FY2021. Since the final year of this proposal was FY2021, the results for three fiscal years were summarized. The present study aims to explore alkali activated materials with high anionic nuclide retention and flowability and their recipes for safe storage and disposal of iron flocculant from the water treatment facility at 1F, and to propose a design of a solidification device that is feasible as an actual plant. In order to achieve these objectives, the following five items were carried out in this study.
Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*
JAEA-Review 2022-038, 102 Pages, 2023/01
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 FY2020, this report summarizes the research results of the "Study on rational treatment/disposal of contaminated concrete waste considering leaching alteration" conducted in FY2021. The present study aims to understand migration behaviors of radionuclides in relation to the properties of concrete altered by leaching, to develop a model to predict concentration profiles, and to analyze waste management scenarios, with a focus on underground concrete structures in contact with contaminated water. Migration behaviors depend on radionuclides and their chemical species. Sorption of I is less significant on C-S-H and C-A-S-H than on hardened cement paste with two orders of magnitude smaller distribution coefficient
, while
of U was the same …
Kawakita, Ryohei; Saito, Akito*; Sakuma, Hiroshi*; Anraku, Sohtaro; Kikuchi, Ryosuke*; Otake, Tsubasa*; Sato, Tsutomu*
Applied Clay Science, 231, p.106722_1 - 106722_7, 2023/01
Times Cited Count:2 Percentile:17.27(Chemistry, Physical)Zheng, X.*; Kato, Masaru*; Uemura, Yohei*; Matsumura, Daiju; Yagi, Ichizo*; Takahashi, Kiyonori*; Noro, Shinichiro*; Nakamura, Takayoshi*
Inorganic Chemistry, 62(3), p.1257 - 1263, 2023/01
Times Cited Count:8 Percentile:77.83(Chemistry, Inorganic & Nuclear)Oka, Hiroshi*; Tanno, Takashi; Yano, Yasuhide; Otsuka, Satoshi; Kaito, Takeji; Hashimoto, Naoyuki*
Journal of Nuclear Materials, 572, p.154032_1 - 154032_8, 2022/12
Times Cited Count:5 Percentile:60.29(Materials Science, Multidisciplinary)9Cr oxide dispersion strengthened steels with slightly different nitrogen concentrations (0.0034 - 0.029 wt%) were prepared and their creep property at 973 K was investigated with microstructural characterization before and after the creep test. The creep strength decreased significantly as the nitrogen concentration increased. Microstructural observation revealed that, in the higher nitrogen concentration specimen, coarse Y-rich inclusions were found along the boundary between transformed ferrite region and residual ferrite region. The solubility difference of nitrogen in and
phase would induce the localized increment of nitrogen concentration in the boundary region during the austenitizing process, resulting in the thermodynamic destabilization and subsequent coarsening of the dispersed oxide particles. The rows of creep voids were found near the rupture part of the crept specimen, suggesting that the coarse inclusions were the starting point of creep void formation and the subsequent premature fracture.
Momma, Yuichiro*; Sakairi, Masatoshi*; Ueno, Fumiyoshi; Otani, Kyohei
Zairyo To Kankyo, 71(5), p.133 - 137, 2022/05
The effect of the corrosion inhibitor on the corrosion of steel under a thin solution layer was investigated. As a result of forming a thin solution layer with a thickness of 1.0-0.2 mm on the specimen, adding a mixed solution of sodium molybdate and aluminum lactate as a corrosion inhibitor, and performing electrochemical measurement, the corrosion inhibitor suppresses the anodic reaction. And in the thin solution layer, it was suggested that the morphology of the protective layer structure by the corrosion inhibitor changed according to the amount of liquid as compared with the bulk immersion.
Momma, Yuichiro*; Sakairi, Masatoshi*; Ueno, Fumiyoshi; Otani, Kyohei
Zairyo To Kankyo, 71(4), p.121 - 125, 2022/04
The effect of solution layer thickness on the atmospheric corrosion of carbon steel was investigated using novel devices fabricated by a 3D printer. These novel devices allowed us to control the solution layer thickness precisely. Potentiodynamic polarization measurements were performed under thickness-controlled solution layer, and oxygen diffusion limiting current density () and anodic current density (
) were measured. As the solution layer become thinner,
increased and
decreased. This result indicates that corrosion accelerates when the solution layer becomes thinner. The diffusion coefficient of oxygen was calculated as 3.20
10
cm
s
from the relationship between
and solution layer thickness, and the critical diffusion thickness was estimated to be 0.87 mm.