Local structure analysis of heavy fermion CePtGa with a honeycomb structure using extended X-ray absorption fine structure

Matsumoto, Yuji*; Watabe, Yuki*; Iesari, F.*; Osumi, Masakatsu*; Ota, Kyugo*; Haga, Yoshinori; Hatada, Keisuke*; Okajima, Toshihiko*

Metals, 15(4), p.436_1 - 436_13, 2025/04

https://doi.org/10.3390/met15040436

Physicochemical characterization of the youngest active domain in major fault zones using the weathering index and X-ray computed tomography

Iwamori, Akiyuki*; Ogita, Yasuhiro; Shimada, Koji; Tateishi, Ryo*; Takagi, Hideo*; Ota, Toru*; Cho, T.*; Kudo, Shunsuke*; Nojiri, Keisuke*; Shigemitsu, Yasumune*; et al.

Engineering Geology, 344, p.107821_1 - 107821_20, 2025/01

https://doi.org/10.1016/j.enggeo.2024.107821

Clarification of the physicochemical characterization of brittle fault rocks is important not only for understanding the history of the fault activity and deformation mechanisms, but also for assessing the siting conditions of important facilities such as nuclear power plants, radioactive waste disposal sites, and oil storage bases. Here, we apply the chemical weathering index (W values) to the brittle fault rocks of the Shiraki-Nyu fault (granite), the Tsuruga fault (geological boundary between granite and greenstone), and the Yamada fault (adamellite), which are active faults in the peripheral area of Wakasa Bay, and their respective protoliths (hard rocks), and investigate the physicochemical characteristics of the youngest active domain of brittle fault rocks based on the relationship between computed tomography data (CT numbers) and alteration intensity (AI values). The W values of the fault rocks are mainly affected by changes in NaO and CaO, corresponding to the elution or deposition of plagioclase and calsite for granite, clinopyroxene and hornblende for greenstone, and plagioclase for adamellite. The W values mainly indicate the effects of hydrothermal alteration up to 50 60 percent and of weathering at over 60 percent. On the other hand, the CT values of the fault rocks are lowest in the fault gouge corresponding to the latest active zone, which was identified as the lowest density zone. In addition, fresh plagioclase fragments are present in each fault gouge of the latest active zone of the active faults in this study. The application of W values to brittle fault rocks is an effective method for understanding the trends of mineralogical variations associated with hydrothermal alteration and weathering in fault rocks, and it is highly possible to improve the accuracy of identifying the youngest active domain in major fault zones through joint analyses of CT numbers.

Validation study on SFR core bowing codes using Joyo ex-core experiment data; Single duct bowing benchmark

Ohgama, Kazuya; Doda, Norihiro; Uwaba, Tomoyuki; Futagami, Satoshi; Tanaka, Masaaki; Yamano, Hidemasa; Ota, Hirokazu*; Ogata, Takanari*; Wozniak, N.*; Shemon, E.*; et al.

Proceedings of International Conference on Nuclear Fuel Cycle (GLOBAL2024) (Internet), 4 Pages, 2024/10

To enhance the accuracy of the safety evaluations in sodium-cooled fast reactors, it is necessary to develop a method to realistically evaluate the reactivity caused by core deformation. In this regard, Japan and the United States jointly conducted a benchmark analysis of thermal bowing experiments of a single duct of Joyo-type fuel assembly. The aim was to confirm the validity of the core bowing analysis codes. Comparisons of analysis and test results revealed that the core bowing analysis codes used by both countries were able to reasonably predict the axial distribution of horizontal duct displacement of a single duct due to thermal bowing and the contact load on the duct pad.

Production cross-sections of residual nuclides from Zr + at 27 MeV/nucleon

Hwang, J.*; Chillery, T.*; Dozono, Masanori*; Imai, Nobuaki*; Michimasa, Shinichiro*; Sumikama, Toshiyuki*; Chiga, Nobuyuki*; Ota, Shinsuke*; Nakayama, Shinsuke; 49 of others*

Progress of Theoretical and Experimental Physics (Internet), 2024(9), p.093D03_1 - 093D03_12, 2024/09

https://doi.org/10.1093/ptep/ptae139

Nuclear transmutation emerges as a promising approach for reprocessing high-level waste, specifically treating long-lived nuclides like Zr from spent fuel. It is essential to accumulate reaction data for these nuclei to advance this prominent treatment and to build a comprehensive understanding of reaction mechanisms. In this study, the residual production cross-sections resulting from proton-induced reactions on Zr were measured at 27 MeV/nucleon in inverse kinematics. At the RIKEN-RIBF facility the OEDO beamline was used to deduce production cross-sections for isotopes, Nb, Zr, and Y. Comparing the results from this study and prior research with calculated excitation functions, a moderate agreement is found with theoretical predictions derived from TALYS and CCONE. Despite the potential limitations of low-energy proton-induced reactions for Zr transmutation, the measured cross-sections offer valuable insights for future considerations in nuclear-waste treatment facilities. This is particularly relevant for facilities exploring innovative methods, such as accelerator-driven systems.

High sensitivity of a future search for effects of -odd/-odd interactions on the 0.75 eV -wave resonance in + forward transmission determined using a pulsed neutron beam

Nakabe, Rintaro*; Auton, C. J.*; Endo, Shunsuke; Fujioka, Hiroyuki*; Gudkov, V.*; Hirota, Katsuya*; Ide, Ikuo*; Ino, Takashi*; Ishikado, Motoyuki*; Kambara, Wataru*; et al.

Physical Review C, 109(4), p.L041602_1 - L041602_4, 2024/04

https://doi.org/10.1103/PhysRevC.109.L041602

Onset of collectivity for argon isotopes close to

Linh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Duguet, T.*; Gmez-Ramos, M.*; Holt, J. D.*; Hu, B. S.*; et al.

Physical Review C, 109(3), p.034312_1 - 034312_15, 2024/03

https://doi.org/10.1103/PhysRevC.109.034312

no abstracts in English

Numerical analyses on perforation damage using test results of reinforced concrete panel subjected to oblique impact

Kang, Z.; Okuda, Yukihiko; Nishida, Akemi; Tsubota, Haruji; Li, Y.

Transactions of the 27th International Conference on Structural Mechanics in Reactor Technology (SMiRT 27) (Internet), 10 Pages, 2024/03

Most studies conducted till now on local damage of reinforced concrete (RC) slab structures subjected to projectile impact are about normal impact, while few research related to oblique impact can be found. The objective of this study is to carry out impact tests under different impact conditions including oblique impacts, to confirm the different impact behaviors of the RC slab structure, to develop an analysis method by investigating the test results and analytical conditions, and to validate the analysis method through comparison with the test results. This study focuses on the scabbing damage which is one of the local damage modes of RC slab. Based on oblique impact test results due to soft projectile with hemispherical nose shape, we investigate the relationship between the criterion related to the concrete fracture and the occurrence of scabbing damage.

Neutron scattering study of antiferromagnet UPtAl

Ota, Kyugo*; Matsumoto, Yuji*; Watabe, Yuki*; Kaneko, Koji; Tabata, Chihiro; Haga, Yoshinori

New Physics; Sae Mulli, 73(12), p.1170 - 1173, 2023/12

https://doi.org/10.3938/NPSM.73.1170

We have performed the neutron scattering study of antiferromagnet UPtAl with the honeycomb lattice to determine the magnetic structure. UPtAl exhibits two phase transitions at = 9 K and = 26 K. In phase I at , the magnetic reflections described by a propagation vector = (1/3, 0, 0) were observed. In phase II at , magnetic reflections of = (1/3, 0, 0) and = (1/2, 0, 0) were observed and the magnetic reflection intensity of = (1/3, 0, 0) is weak but finite. The hysteresis in the temperature dependent intensities is observed across the phase transition at , suggesting that the transition at is of first order.

Studying the impact of deuteron non-elastic breakup on Zr + d reaction cross sections measured at 28 MeV/nucleon

Chillery, T.*; Hwang, J.*; Dozono, Masanori*; Imai, Nobuaki*; Michimasa, Shinichiro*; Sumikama, Toshiyuki*; Chiga, Nobuyuki*; Ota, Shinsuke*; Nakayama, Shinsuke; 49 of others*

Progress of Theoretical and Experimental Physics (Internet), 2023(12), p.121D01_1 - 121D01_11, 2023/12

https://doi.org/10.1093/ptep/ptad139

The deuteron is a loosely bound system which can easily break up into its constituent proton and neutron whilst in the presence of Coulomb and nuclear fields. Previous experimental studies have shown that this breakup process has a significant impact on residual nucleus production from deuteron bombardment in the high energy range of 50 - 210 MeV/nucleon. However, there remains a lack of cross-section data at energies below 50 MeV/nucleon. The current study determined Zr + d reaction cross sections under inverse kinematics at approximately 28 MeV/nucleon using the BigRIPS separator, OEDO beamline, and SHARAQ spectrometer. Cross sections from this research were compared with previous measurements and theoretical calculations. The experimental results show a large enhancement of the production cross sections of residual nuclei, especially those produced from a small number of particle emissions, compared to the proton-induced reaction data at similar bombarding energy. The DEURACS calculation, which quantitatively takes deuteron-breakup effects into account, reproduces the data well. As a long-lived fission product, Zr remains a challenge for nuclear waste disposal and treatment. This study's low-energy data may assist future consideration of nuclear-waste treatment facilities, where Zr + d may feasibly transmute the waste into short-lived/stable nuclei.

The Role of collision ionization of K-shell ions in nonequilibrium plasmas produced by the action of super strong, ultrashort PW-class laser pulses on micron-scale argon clusters with intensity up to 5 10 W/cm

Skobelev, I. Yu.*; Ryazantsev, S. N.*; Kulikov, R. K.*; Sedov, M. V.*; Filippov, E. D.*; Pikuz, S. A.*; Asai, Takafumi*; Kanasaki, Masato*; Yamauchi, Tomoya*; Jinno, Satoshi; et al.

Photonics (Internet), 10(11), p.1250_1 - 1250_11, 2023/11

https://doi.org/10.3390/photonics10111250

It is challenging to clearly distinguish the impacts of the optical field and collisional ionization in the evolution of the charge state of a plasma produced when matter interacts with high-intensity laser pulses. In this work, time-dependent calculations of plasma kinetics are used to show that it is possible only when low-density gaseous targets with sufficiently small clusters are used. In the case of Ar plasma, the upper limit of the cluster radius was estimated to be m.