Phonon-enhanced spin-dependent Seebeck effect in magnetic carbon films

Wang, C.*; Yang, Z.*; Ren, Q.*; Mo. X.*; Kikkawa, Takashi; Daimon, Shunsuke*; Diao, D.*; Saito, Eiji

Carbon, 246, p.120909_1 - 120909_7, 2026/01

https://doi.org/10.1016/j.carbon.2025.120909

Diffusion of Cs, I and HDO onto pre-Neogene sedimentary rocks

Hou, L.*; Fukatsu, Yuta; Okamoto, Shunichi*; Toda, Kanako*; Nakata, Kotaro*; Nohara, Shintaro*; Ishidera, Takamitsu; Saito, Takumi*

Journal of Nuclear Science and Technology, 62(11), p.1121 - 1134, 2025/11

https://doi.org/10.1080/00223131.2025.2528482

Fabrication of low-O/M fast reactor MOX fuel and analysis on its oxygen potential behaviors

Hirooka, Shun; Vauchy, R.; Horii, Yuta; Sunaoshi, Takeo*; Saito, Kosuke

Proceedings of TopFuel 2025; Nuclear Reactor Fuel Performance Conference (Internet), 10 Pages, 2025/10

Reducing the oxygen-to-metal (O/M) ratio in MOX fuels plays an important role in suppressing the corrosion depth in the cladding due to fuel-cladding chemical interaction (FCCI), which is the key to determining the lifetime of fast reactor MOX fuels. Owing to a number of irradiation and post-irradiation experiments, a clear decreasing trend in the corrosion depth with lower O/M ratio in the as-fabricated MOX pellet was reported, whereas a significant redistribution of the O/M ratio in a pellet driven by the radial temperature gradient during irradiation could supply a higher oxygen potential near the pellet periphery where the FCCI should occur. The reduction of the O/M ratio in the MOX pellet fabrication processes can be achieved by heat treatment by taking high temperature, longer time, and lower oxygen partial pressure in the gas into account; the properties governing the reduction are not sufficiently studied. This study demonstrated the variation of O/M ratio in MOX pellets and the in-situ O/M ratio during the heat treatment was analyzed by using a thermogravimeter, which revealed a decreasing behavior during heating and dwell as well as an increasing behavior in the O/M ratio during the cooling step. Furthermore, the redistribution of O/M ratio, analyzed by Sari's model, was discussed to investigate the O/M ratio and the oxygen potential near the pellet periphery which is likely to have a more direct influence on the FCCI than the as-fabricated O/M ratio. By using the recent oxygen potential data on MOX, it is found that the oxygen potential profile in the radial direction is especially drastic near the pellet periphery and is sensitive to the as-fabricated O/M ratio.

Control and irradiation behaviors of oxygen potential of MOX fuel

Hirooka, Shun; Vauchy, R.; Horii, Yuta; Sunaoshi, Takeo*; Saito, Kosuke; Ozawa, Takayuki

Proceedings of Workshop on Fuel Performance Assessment and Behaviour for Liquid Metal Cooled Fast Reactors (Internet), 8 Pages, 2025/07

no abstracts in English

Oxygen potential of plutonium and plutonium-americium dioxides

Vauchy, R.; Hirooka, Shun; Saito, Kosuke

Materials Today Communications (Internet), 41, p.110676_1 - 110676_17, 2024/12

https://doi.org/10.1016/j.mtcomm.2024.110676

Oxygen potential measurements of PuO reported in the open literature were reviewed and re-interpreted using the defect chemistry model developed by our team. An empirical, easy-to-use, relationship connecting the O/Pu ratio, the equilibrium oxygen potential, and the temperature is proposed based on the interpolation of the experimental data in the 953-2100 K temperature range. The effect of americium on the oxygen potential of PuO is also discussed.

Conceptual study of Post Irradiation Examination (PIE) Facility at J-PARC

Saito, Shigeru; Meigo, Shinichiro; Makimura, Shunsuke*; Hirano, Yukinori*; Tsutsumi, Kazuyoshi*; Maekawa, Fujio

JAEA-Technology 2023-025, 48 Pages, 2024/03

JAEA-Technology-2023-025.pdf:3.11MB

JAEA has been developing Accelerator-Driven Systems (ADS) for research and development of nuclear transmutation using accelerators in order to reduce the volume and hazardousness of high-level radioactive waste generated by nuclear power plants. In order to prepare the material irradiation database necessary for the design of ADS and to study the irradiation effects in Lead-Bismuth Eutectic (LBE) alloys, a proton irradiation facility is under consideration at J-PARC. In this proton irradiation facility, 250 kW proton beams will be injected into the LBE spallation target, and irradiation tests under LBE flow will be performed for candidate structural materials for ADS. Furthermore, semiconductor soft-error tests, medical RI production, and proton beam applications will be performed. Among these, Post Irradiation Examination (PIE) of irradiated samples and RI separation and purification will be carried out in the PIE facility to be constructed near the proton irradiation facility. In this PIE facility, PIE of the equipment and samples irradiated in other facilities in J-PARC will also be performed. This report describes the conceptual study of the PIE facility, including the items to be tested, the test flow, the facilities, the test equipment, etc., and the proposed layout of the facility.

Latent ion tracks were finally observed in diamond

Amekura, Hiroshi*; Chettah, A.*; Narumi, Kazumasa*; Chiba, Atsuya*; Hirano, Yoshimi*; Yamada, Keisuke*; Yamamoto, Shunya*; Leino, A. A.*; Djurabekova, F.*; Nordlund, K.*; et al.

Nature Communications (Internet), 15, p.1786_1 - 1786_10, 2024/02

https://doi.org/10.1038/s41467-024-45934-4

Injecting high-energy heavy ions in the electronic stopping regime into solids can create cylindrical damage zones called latent ion tracks. Although these tracks form in many materials, none have ever been observed in diamond, even when irradiated with high-energy GeV uranium ions. Here we report the first observation of ion track formation in diamond irradiated with 2-9 MeV C fullerene ions. Depending on the ion energy, the mean track length (diameter) changed from 17 (3.2) nm to 52 (7.1) nm. High resolution scanning transmission electron microscopy (HR-STEM) indicated the amorphization in the tracks, in which -bonding signal from graphite was detected by the electron energy loss spectroscopy (EELS).

Development of a non-destructive depth-selective quantification method for sub-percent carbon contents in steel using negative muon lifetime analysis

Ninomiya, Kazuhiko*; Kubo, Kenya*; Inagaki, Makoto*; Yoshida, Go*; Chiu, I.-H.; Kudo, Takuto*; Asari, Shunsuke*; Sentoku, Sawako*; Takeshita, Soshi*; Shimomura, Koichiro*; et al.

Scientific Reports (Internet), 14, p.1797_1 - 1797_8, 2024/01

https://doi.org/10.1038/s41598-024-52255-5

The amount of C in steel, which is critical in determining its properties, is strongly influenced by steel production technology. We propose a novel method of quantifying the bulk C content in steel non-destructively using muons. This revolutionary method may be used not only in the quality control of steel in production, but also in analyzing precious steel archaeological artifacts. A negatively charged muon forms an atomic system owing to its negative charge, and is finally absorbed into the nucleus or decays to an electron. The lifetimes of muons differ significantly, depending on whether they are trapped by Fe or C atoms, and identifying the elemental content at the muon stoppage position is possible via muon lifetime measurements. The relationship between the muon capture probabilities of C/Fe and the elemental content of C exhibits a good linearity, and the C content in the steel may be quantitatively determined via muon lifetime measurements. Furthermore, by controlling the incident energies of the muons, they may be stopped in each layer of a stacked sample consisting of three types of steel plates with thicknesses of 0.5 mm, and we successfully determined the C contents in the range 0.20 - 1.03 wt% depth-selectively, without sample destruction.

Pd nanoparticles on the outer surface of microporous aluminosilicates for the direct alkylation of benzenes using alkanes

Misaki, Satoshi*; Miwa, Hiroko*; Ito, Takashi; Yoshida, Takefumi*; Hasegawa, Shingo*; Nakamura, Yukina*; Tokutake, Shunta*; Takabatake, Moe*; Shimomura, Koichiro*; Chun, W.-J.*; et al.

ACS Catalysis, 13(18), p.12281 - 12287, 2023/09

https://doi.org/10.1021/acscatal.3c02309

Study of the and shell gap for Ti and V by the first high-precision multireflection time-of-flight mass measurements at BigRIPS-SLOWRI

Iimura, Shun*; Rosenbusch, M.*; Takamine, Aiko*; Tsunoda, Yusuke*; Wada, Michiharu*; Chen, S.*; Hou, D. S.*; Xian, W.*; Ishiyama, Hironobu*; Yan, S.*; et al.

Physical Review Letters, 130(1), p.012501_1 - 012501_6, 2023/01

https://doi.org/10.1103/PhysRevLett.130.012501