RI production using research reactors; Activities at JRR-3

Kinase, Masami

Radioisotopes, 74(2), p.233 - 238, 2025/07

https://doi.org/10.3769/radioisotopes.740212

no abstracts in English

Nacre-like MXene/polyacrylic acid layer-by-layer multilayers as hydrogen gas barriers

Auh, Y. H.*; Neal, N. N.*; Arole, K.*; Regis, N. A.*; Nguyen, T.*; Ogawa, Shuichi*; Tsuda, Yasutaka; Yoshigoe, Akitaka; Radovic, M.*; Green, M. J.*; et al.

ACS Applied Materials & Interfaces, 17(21), p.31392 - 31402, 2025/05

https://doi.org/10.1021/acsami.5c03632

Conceptual study of J-PARC Proton Beam Irradiation Facility

Meigo, Shinichiro; Iwamoto, Hiroki; Sugihara, Kenta*; Hirano, Yukinori*; Tsutsumi, Kazuyoshi*; Saito, Shigeru; Maekawa, Fujio

JAEA-Technology 2024-026, 123 Pages, 2025/03

JAEA-Technology-2024-026.pdf:14.22MB

Based on the design of the ADS Target Test Facility (TEF-T) at the J-PARC Transmutation Experimental Facility, a conceptual study was conducted on the J-PARC proton beam irradiation facility. This research was carried out based on the recommendations of the Nuclear Transmutation Technology Evaluation Task Force of the MEXT. The recommendations state that it is desirable to consider facility specifications that can make the most of the benefits of using the existing J-PARC proton accelerator while also solving the engineering issues of the ADS. We considered facilities that could respond to a variety of needs while reducing the facilities that were not needed in the TEF-T design. In order to clarify these diverse needs, we investigated the usage status of representative accelerator facilities around the world. As a result, it became clear that the main purposes of these facilities were (1) Material irradiation, (2) Soft error testing of semiconductor devices using spallation neutrons, (3) Production of RI for medical use, and (4) Proton beam use, and we investigated the facilities necessary for these purposes. In considering the facility concept, we assumed a user community in 2022 and reflected user opinions in the facility design. This report summarizes the results of the conceptual study of the proton irradiation facility, various needs and responses to them, the roadmap for facility construction, and future issues.

Annual report of Nuclear Science Research Institute, JFY 2023

Nuclear Science Research Institute

JAEA-Review 2024-058, 179 Pages, 2025/03

JAEA-Review-2024-058.pdf:7.42MB

Nuclear Science Research Institute (NSRI) is composed of Planning and Management Department and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Criticality and Hot Examination Technology and Department of Decommissioning and Waste Management, and each department manages facilities and develops related technologies to achieve the "Medium- to Long-term Plan" successfully and effectively. And, four research centers which are Advanced Science Research Center, Nuclear Science and Engineering Center, Nuclear Engineering Research Collaboration Center and Materials Sciences Research Center, belong to NSRI. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2023 as well as the activity on research and development carried out by Collaborative Laboratories for Advanced Decommissioning Science, Nuclear Safety Research Center and activities of Nuclear Human Resource Development Center, using facilities of NSRI.

Renovation and restart of STACY (Static Experiment Critical Facility)

Sono, Hiroki

Robutsuri No Kenkyu (Internet), (78), 12 Pages, 2025/03

https://rpg.jaea.go.jp/else/rpd/annual_report/pdf78/No78-03.pdf

The Static Experiment Critical Facility (STACY) was renovated from a "solution fuel reactor" to a "reactor using fuel rods and light water moderator", and restarted operation on August 2, 2024, after a hiatus of 13 years and 8 months. During that time, it took 8 years and 11 months to obtain its permission and approval, 3 years and 1 month for its construction, and 4 months for pre-operation inspections on the reactor performance. This article reports on the history of STACY from its birth to its restart of operation, as well as its future utilization.

Renovation and restart of STACY (Static Experiment Critical Facility)

Sono, Hiroki

Genshiryoku Kiko, Genken OB Kai Kaiho, (86), P. 2, 2025/01

The Static Experiment Critical Facility (STACY) was renovated from a "solution fuel reactor" to a "reactor using fuel rods and light water moderator", and restarted operation on August 2, 2024, after a hiatus of 13 years and 8 months. During that time, it took 8 years and 11 months to obtain its permission and approval, 3 years and 1 month for its construction, and 4 months for pre-operation inspections on the reactor performance. This article reports on the history of STACY from its birth to its restart of operation, as well as its future utilization.

Assessment of individual external exposure doses based on environmental radiation in areas affected by the Fukushima Daiichi Nuclear Power Station accident

Sato, Rina; Yoshimura, Kazuya; Sanada, Yukihisa; Mikami, Satoshi; Yamada, Tsutomu*; Nakasone, Takamasa*; Kanaizuka, Seiichi*; Sato, Tetsuro*; Mori, Tsubasa*; Takagi, Marie*

Environment International, 194, p.109148_1 - 109148_8, 2024/12

https://doi.org/10.1016/j.envint.2024.109148

Assessment of individual external doses from ambient dose equivalents is used for predictive and retrospective assessments where personal dosimeters are not applicable. However, it tends to contain more errors than assessment by personal dosimetry due to various parameters. Therefore, in order to accurately assess the individual dose from ambient dose equivalents, a model that estimates effective doses considering life patterns and the shielding effects by buildings and vehicles, were developed in this study. The model parameters were examined using robust datasets of environmental radiation measured in the areas affected by the Fukushima Daiichi Nuclear Power Station accident in 2020 to 2021. The accuracy of the model was validated by comparison with 106 daily personal doses measured in Fukushima Prefecture in 2020. The measured personal dose was well reproduced by the model-estimated effective dose, showing that the model can be used to assess the individual exposure dose, similar to personal dosimetry. Furthermore, this model is an effective tool for radiation protection, as it can estimate the individual dose predictively and retrospectively by using environmental radiation data.

Nuclear fuel storage container opening inspection and metal inner container repacking

Licensing Application Group, Fuels and Materials Department

JAEA-Testing 2024-002, 20 Pages, 2024/08

JAEA-Testing-2024-002.pdf:1.46MB

The contamination accident occurred at Plutonium Fuel Research Facility (PFRF) in Japan Atomic Energy Agency (JAEA) Oarai Research and Development Institute on June 6, 2017. During the work of opening the fuel storage container and checking the properties of the contents, the plastic bag that double-packed the inner container burst. The scattering of the fuels contaminated the work room and exposed the worker. The cause of the plastic bag burst was that the enclosed epoxy resin was decomposed by -rays and the internal pressure increased due to the generated hydrogen gas. The 54 storage containers containing plutonium held at PFRF also at risk of increasing internal pressure. Therefore, an opening inspection was conducted to confirm the contents of the storage container in the hot cell. In addition, the contents of storage containers that may generate gas were stabilized. We are planning to transport the fuel storage containers out to another facility for the decommission of PFRF. The other 9 storage containers include oxide raw material powder: Pu + U in excess of 220 g. In order to decrease to less than 220 g (the limit of transport cask), the metal inner containers in the storage container were taken out and repacked in another storage container. This report describes advance measures such as permit application and the details of about storage container opening inspection and metal inner container repacking.

Study on the evaluation methodology of the radioactivity concentration in low-level radioactive concrete wastes generated from JPDR

Aono, Ryuji; Haraga, Tomoko; Kameo, Yutaka

JAEA-Technology 2024-006, 48 Pages, 2024/06

JAEA-Technology-2024-006.pdf:1.77MB

In the future, radioactive waste which generated from nuclear research facilities in Japan Atomic Energy Agency are planning to be buried for the near surface disposal. It is necessary to establish the method to evaluate the radioactivity concentrations of the radioactive wastes. In this work, we studied the evaluation methodology of the radioactivity concentrations in concrete waste generated from JPDR. In order to construct the evaluation methodology of the radioactivity concentration, the validity of the evaluation methods was confirmed by mainly theoretical calculation and using the result of radiochemical analysis. Correcting the theoretical calculations using results of nuclide analysis, it is possible to evaluate the radioactivity concentrations of nuclides preliminary selected.

Perpendicular magnetic anisotropy of thin films

Takanashi, Koki; Seki, Takeshi*

Magune, 19(3), p.100 - 106, 2024/06

Perpendicular magnetic anisotropy of thin films currently plays an important role in spintronics as well as magnetic recording. Regarding perpendicular magnetic anisotropy, in this article, the fundamentals, the research history, and the recent research trends are reviewed, showing specific examples with perpendicular magnetization such as magnetic multilayers, ordered alloy films, rare earth-transition metal amorphous alloy films, and inhomogeneous or granular films. The physical origins for perpendicular magnetic anisotropy, including interface anisotropy due to structural symmetry breaking, magnetoelastic anisotropy due to strain, bulk-type magnetocrystalline anisotropy, and directional pair ordering of atoms, are discussed in each example.