Unveiling the effects of Mn, Cr, Al, and Si on the low-temperature tempering behaviors of high-carbon martensite

Zhang, Y.*; Marusawa, Kenji*; Kudo, Kohei*; Morooka, Satoshi; Gong, W.; Harjo, S.; Miyamoto, Goro*; Furuhara, Tadashi*

Journal of Materials Science & Technology, 275, p.250 - 259, 2026/12

https://doi.org/10.1016/j.jmst.2026.04.015

Interactions between U-Zr-O and concrete near the melting range of concrete

Sudo, Ayako; Sato, Takumi; Nagae, Yuji

Journal of Nuclear Materials, 632, p.156936_1 - 156936_16, 2026/10

https://doi.org/10.1016/j.jnucmat.2026.156936

Current molten corium concrete interaction codes are based on large-scale tests in which core materials interact with concrete and the initial temperature of the molten pool is below 2000C. Suboxides such as U-Zr-O may react with concrete at lower temperatures near the melting range of concrete. Investigating the reactions between core materials and concrete near the melting range of concrete is essential for advancing severe accident analyses. As a result of small-scale reaction tests between concrete and U-Zr-O under an Ar atmosphere at 1200C and 1300C, held for 2 hours, a Si-Zr-U-O layer was formed at the reaction interface. At 1500C, held for 2 hours, three layers were formed: (i)Si-Zr-U-O layer, (ii) (U,Zr)O and concrete, and (iii) Si-Zr metallic precipitates. The thermodynamic analysis, indicate that Ca dissolves in (U,Zr)O, whereas U is not predicted to be present in the Si-Zr-U-O layer. These discrepancies arise because the calculations assume complete mixing of the core materials and concrete. The present study demonstrated that, within the temperature range of 1200C-1500C, the reaction layer formed between U-Zr-O and concrete became thicker with increasing temperature, and that the composition of the reaction layer could not be adequately predicted by thermodynamic calculations alone.

Changes in surface conditions of cobalt oxides on stainless steel in nitrogen ultrafine bubble water under ultrasonic irradiation

Nakahara, Masaumi; Sasaki, Misa*; Yamagata, Ryohei*; Koka, Masashi*; Moriguchi, Tetsuji*

Nuclear Instruments and Methods in Physics Research B, 579, p.166229_1 - 166229_6, 2026/10

https://doi.org/10.1016/j.nimb.2026.166229

To decrease secondary radioactive waste, a removal technique of contaminants with ultrafine bubble water has been proposed for decommissioning of nuclear reactors. In this study, removal experiments with ultrafine bubbles were performed with simulated contaminants precipitated Co oxides, and the surface conditions of test specimens were analyzed and evaluated.

Nanoplastics reprogram fungal metabolism to reshape extracellular microenvironments and manganese biomineralization

Wu, C.*; Qiu, X.*; Tanaka, Kazuya; Tani, Yukinori*; Lloyd, J. R.*; Yu, Q.*

Bioresource Technology, 456, p.134916_1 - 134916_9, 2026/09

https://doi.org/10.1016/j.biortech.2026.134916

no abstracts in English

Unveiling post-deformation transformation mechanism and ferrite microstructure evolution for tailoring mechanical properties of low-carbon martensitic steels

Tong, Z.*; Xia, C.*; Li, W.*; Ding, W.*; Guo, B.*; Min, N.*; Gong, W.; Harjo, S.; Tsuji, Nobuhiro*

Journal of Materials Science & Technology, 266, p.127 - 140, 2026/09

https://doi.org/10.1016/j.jmst.2025.12.004

Clarification of key input parameters for site boundary dose due to criticality of fuel debris at the Fukushima Daiichi Nuclear Power Plant

Fukuda, Kodai; Shiba, Shigeki*; Iwahashi, Daiki*; Gunji, Satoshi

Journal of Nuclear Science and Technology, 63(9), p.1001 - 1014, 2026/09

https://doi.org/10.1080/00223131.2026.2648997

Investigating the N(,)O reaction rates via the F(,)F reaction

Kim, S. H.*; Chae, K. Y.*; Asai, Masato; Hirose, Kentaro; Sato, Tetsuya; Makii, Hiroyuki; Nishio, Katsuhisa; Orlandi, R.; Smallcombe, J.; Suzaki, Fumi; et al.

Journal of the Korean Physical Society, 89(5), p.488 - 493, 2026/09

https://doi.org/10.1007/s40042-026-01643-3

no abstracts in English

Initiatives for technical succession and human resource development through on-site inspection of substation equipment

Takahashi, Shinsuke; Nishida, Tetsuro; Kawasaki, Ichio; Kanazawa, Koichiro; Shimazaki, Takejiro

Nihon Hozen Gakkai Dai-22-Kai Gakujutsu Koenkai Yoshishu, 2 Pages, 2026/09

Inspecting substation equipment is essential for ensuring safety; however, variations in employee knowledge levels and years of experience have led to a challenge of technical expertise being siloed within individuals. Therefore, we are implementing on-site inspection procedures that incorporate On-the-Job Training (OJT) provided by experienced personnel, aiming to systematically improve technical capabilities and facilitate the sharing of specialized knowledge.

Sustainable management for Japan's cedar stands towards national carbon neutrality

Ota, Masakazu; Takagi, Kentaro*; Liang, N.*; Takahashi, Yoshiyuki*; Koarashi, Jun

Resources, Conservation & Recycling, 235, p.109089_1 - 109089_9, 2026/09

https://doi.org/10.1016/j.resconrec.2026.109089

To achieve carbon neutrality by 2050, Japan is revitalizing forestry. However, it is unclear what specific forest management method should be implemented. Using a numerical model, here we explore carbon balance and economy of currently feasible managements for Japanese cedar plantation, the Japan's most economically important stand. We show that a repetition of 45-year rotation cycle most sequesters carbon dioxide from the atmosphere, also generating highest revenue from wood production. Applying this management to domestic cedar stands contributes 35%-73% of Japan's 2030 interim target of carbon dioxide absorption by forests, offsetting 1.4%-3.0% of national net emission target. However, sustainability of the management depends on subsidies, requiring over two-thirds of forestry costs. These indicate continued and sufficient support for the forestry sector is necessary to enable Japan's cedar stands to significantly contribute to carbon neutrality.

Development and validation of an irradiation noise reduction method for strain gauge measurement data on fuel rod cladding in simulated reactivity-initiated accident experiments

Nakamura, Tomoki; Mihara, Takeshi; Udagawa, Yutaka; Katsuyama, Jinya; Kakiuchi, Kazuo

JAEA-Technology 2026-012, 94 Pages, 2026/08

JAEA-Technology-2026-012.pdf:4.02MB
JAEA-Technology-2026-012-appendix(CD-ROM).zip:0.15MB

Nuclear Safety Research Reactor (NSRR) of Japan Atomic Energy Agency (JAEA) is a test research reactor to observe and analyze fuel rod behavior under conditions simulating reactivity-initiated accidents (RIA). In the NSRR experiments, strain gauges are employed to measure the mechanical strain on the surface of the fuel rod cladding. However, the measurement data from the strain gauge instrumentation contained signals believed to be noise during pulse irradiation, making it difficult to obtain the true deformation of the test fuel rod from the data. In this report, the noise signals obtained from strain gauges were analyzed in terms of their waveform characteristics and amplitudes, and the relationships between these noise signals and reactor power, as well as various influencing factors such as installation conditions of the strain gauge instrumentation, measurement conditions, and the strain gauge manufacturer, were clarified. Furthermore, based on these analyses, a model for predicting the noise signal waveform for the purpose of removing noise components from strain gauge measurement data was developed. This report presents the results of the development and verification of our proposed method obtained from the strain gauge during RIA simulated test by NSRR.