Change in dislocation density via ausforming in Fe-5%Mn-C alloy with lath martensitic structure

Takanashi, Misa*; Hidaka, Ryota*; Okubo, Kota*; Masumura, Takuro*; Tsuchiyama, Toshihiro*; Morooka, Satoshi; Maeda, Takuya*; Nakamura, Shuichi*; Uemori, Ryuji*

ISIJ International, 65(9), p.1384 - 1393, 2025/08

https://doi.org/10.2355/isijinternational.ISIJINT-2025-090

Change in dislocation density via ausforming in Fe-5%Mn-C alloy with lath martensitic structure

Takanashi, Misa*; Hidaka, Ryota*; Okubo, Kota*; Masumura, Takuro*; Tsuchiyama, Satoshi*; Morooka, Satoshi; Maeda, Takuya*; Nakamura, Shuichi*; Uemori, Ryuji*

Tetsu To Hagane, 111(9), p.503 - 513, 2025/06

https://doi.org/10.2355/tetsutohagane.TETSU-2024-092

A Decade of neutron diffraction study of iron hydrides

Aoki, Katsutoshi*; Machida, Akihiko*; Saito, Hiroyuki*; Hattori, Takanori

Koatsuryoku No Kagaku To Gijutsu, 35(1), p.4 - 11, 2025/03

https://doi.org/10.4131/jshpreview.35.4

Iron reacts with hydrogen to form solid solutions with body-centered cubic, face-centered cubic, hexagonal close packed, and double hexagonal close packed structures at high temperatures and high pressures. Neutron diffraction is the most powerful tool for determining the occupation sites and occupancies of hydrogen atoms dissolved in a metal lattice. Structural parameters, including hydrogen occupation sites and occupancies, are refined via Rietveld analysis for neutron diffraction data. We present our expertise in Rietveld refinement of iron hydrides accumulated over 10 years.

Development of genetic and electrochemical diagnosis and inhibition technologies for invisible corrosion caused by microorganisms (Contract research); FY2022 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; National Institute for Materials Science*

JAEA-Review 2023-031, 101 Pages, 2024/01

JAEA-Review-2023-031.pdf:24.47MB

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 FY2020, this report summarizes the research results of the "Development of genetic and electrochemical diagnosis and inhibition technologies for invisible corrosion caused by microorganisms" conducted from FY2020 to FY2022. The present study aims to develop innovative diagnostic techniques such as accelerated test specimens and on-site genetic testing for microbially induced and accelerated corrosion of metallic materials (microbially influenced corrosion, MIC), and to identify the conditions that promote MIC at 1F for proposing methods to prevent MIC through water quality and environmental control.

Development of genetic and electrochemical diagnosis and inhibition technologies for invisible corrosion caused by microorganisms (Contract Research); FY2021 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; National Institute for Materials Science*

JAEA-Review 2022-045, 82 Pages, 2023/01

JAEA-Review-2022-045.pdf:4.6MB

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 FY2020, this report summarizes the research results of the "Development of genetic and electrochemical diagnosis and inhibition technologies for invisible corrosion caused by microorganisms" conducted in FY2021. The present study aims to develop innovative diagnostic techniques such as accelerated test specimens and on-site genetic testing for microbially induced and accelerated corrosion of metallic materials (microbially influenced corrosion, MIC), and to identify the conditions that promote MIC at 1F for proposing methods to prevent MIC through water quality and environmental control. We also aim to develop a research base based on materials, microorganisms, and electrochemistry, to develop technologies that can be used by engineers in the field, …

Current status of new research reactor at the Monju Site

Mineo, Hideaki

Nihon Genshiryoku Gakkai-Shi ATOMO, 64(11), p.617 - 621, 2022/11

https://doi.org/10.3327/jaesjb.64.11_617

In December 2016 Decisions were made by the Government on the Fast Breeder Prototype Reactor "Monju", which were decommissioning of the reactor and installation of a new research reactor at the Monju site. After the decisions, MEXT started research to list reactor candidates suitable for the site. Among the candidates, medium power reactor type of which thermal output less than 10,000 kW was chosen to utilize neutron beams. Then, from 2020, MEXT launched an entrusted business and adopted JAEA, Kyoto University and University of Fukui as the core institutions of the business to carry out the conceptual design. This paper describes the system to proceed the conceptual design and to examine the utilization management of the new research reactor and also shows their status.

Determination of site occupancy of boron in 6H-SiC by multiple-wavelength neutron holography

Hayashi, Koichi*; Lederer, M.*; Fukumoto, Yohei*; Goto, Masashi*; Yamamoto, Yuta*; Happo, Naohisa*; Harada, Masahide; Inamura, Yasuhiro; Oikawa, Kenichi; Oyama, Kenji*; et al.

Applied Physics Letters, 120(13), p.132101_1 - 132101_6, 2022/03

https://doi.org/10.1063/5.0080895

Numerical reproduction of dissolved U concentrations in a PO-treated column study of Hanford 300 area sediment using a simple ion exchange and immobile domain model

Saito, Tatsuo; Sato, Kazuhiko; Yamazawa, Hiromi*

Journal of Environmental Radioactivity, 237, p.106708_1 - 106708_9, 2021/10

https://doi.org/10.1016/j.jenvrad.2021.106708

We succeeded at numerical reproduction of dissolved U concentrations from column experiments with PO-treated Hanford 300 Area sediment. The time-series curves of dissolved U concentrations under various Darcy flow rate conditions were reproduced by the numerical model in the present study through optimization of the following parameters:(i) the mass of U in mobile domain (on surface soil connected to the stream) and the rest of the total U left as precipitation in immobile domain (isolated in deep soil);(ii) the mixing ratio between immobile and mobile domains, to fit the final recovering curve of concentration; and (iii) the cation exchange capacity (CEC) and equilibrium constant (k) of the exchange reaction of UO and H on simulated soil surface (), to fit the transient equilibrium concentration, forming the bed of the bathtub curve.

Early emergency responses of the Japan Atomic Energy Agency against the Fukushima Daiichi Nuclear Power Station Accident in 2011

Okuno, Hiroshi; Sato, Sohei; Kawakami, Takeshi; Yamamoto, Kazuya; Tanaka, Tadao

Journal of Radiation Protection and Research, 46(2), p.66 - 79, 2021/06

https://doi.org/10.14407/jrpr.2020.00185

The nuclear accident at the Fukushima Daiichi Nuclear Power Station (NPS) of Tokyo Electric Power Company (TEPCO) was a typical one of the disastrous damages that induced evacuation of the residents around the NPS, which was triggered by the hugest earthquake and associated tsunami. This paper summarized early responses of the Japan Atomic Energy Agency (JAEA), especially of its Nuclear Emergency Assistance and Training Center (NEAT) to the off-site emergencies associated with the TEPCO's Fukushima Daiichi NPS. The paper addressed activities of emergency preparedness of the NEAT before 2011 in relevant to the TEPCO's Fukushima Daiichi NPS, the situation of the NEAT on March 11, 2011, and its early responses to the related off-site emergencies including those caused by the accident at the TEPCO's Fukushima Daiichi NPS. The paper also discussed issues associated with complex disasters.

Development of gel filler that facilitates fuel debris retrieval (Contract research); FY2018 Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development

Collaborative Laboratories for Advanced Decommissioning Science; Osaka University*

JAEA-Review 2019-029, 36 Pages, 2020/02

JAEA-Review-2019-029.pdf:2.33MB

JAEA/CLADS, had been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. The Project aims to contribute to solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. 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 Gel Filler that Facilitates Fuel Debris Retrieval". When gel materials such as polymer, silicate and clay minerals with adjusted viscosity are used in the process of debris retrieval, the gel would not leak down from the damaged parts, resulting in the reduction of surrounding air dose rate. In addition, gel materials can reduce the diffusion and scattering of dust that is produced by cutting. For these reasons, we propose a method where inside of a containment vessel is filled by gel materials in order to simplify the debris retrieval.