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Okuizumi, Mao*; Auton, C. J.*; Endo, Shunsuke; Fujioka, Hiroyuki*; Hirota, Katsuya*; Ino, Takashi*; Ishizaki, Kohei*; Kimura, Atsushi; Kitaguchi, Masaaki*; Koga, Jun*; et al.
Physical Review C, 111(3), p.034611_1 - 034611_6, 2025/03
Times Cited Count:0 Percentile:0.00(Physics, Nuclear)Murakami, Masashi; Yoshida, Yukihiko; Nango, Nobuhito*; Kubota, Shogo*; Kurosawa, Takuya*; Sasaki, Toshiki
Journal of Nuclear Science and Technology, 12 Pages, 2025/02
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)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
Times Cited Count:1 Percentile:0.00(Engineering, Geological)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.
Kang, Z.; Okuda, Yukihiko; Nishida, Akemi; Tsubota, Haruji; Ito, Masaharu; Li, Y.
Proceedings of 31st International Conference on Nuclear Engineering (ICONE31) (Internet), 9 Pages, 2024/11
Most studies conducted till now on local damage of reinforced concrete (RC) slab structures subjected to missile 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 effect of the stiffness of the supports for oblique impact on the reaction forces of RC slab. Until now, static loading tests were conducted to confirm the stiffnesses of the supporting parts that supported the RC specimen during oblique impact tests. Based on the obtained load-displacement relationships, and so on, the stiffnesses of the supporting parts are estimated.
Wozniak, N.*; Shemon, E.*; Feng, B.*; Ohgama, Kazuya; Doda, Norihiro; Uwaba, Tomoyuki; Futagami, Satoshi; Tanaka, Masaaki; Yamano, Hidemasa; Ota, Hirokazu*; 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 using multiple ducts 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 thermal bowing of a row of assemblies.
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.
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
Times Cited Count:0 Percentile:0.00(Physics, Multidisciplinary)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.
Koda, Yuya; Matsuno, Hiroki; Matsushima, Akira; Kubota, Shintaro; Toda, Keisuke; Nakamura, Yasuyuki
JAEA-Review 2024-003, 38 Pages, 2024/06
"Fugen Decommissioning Engineering Center", in planning and carrying out our decommissioning technical development, organizes "Technical special committee on Fugen decommissioning" which consists of the members well-informed, aiming to make good use of Fugen as a place for technological development which is opened domestic and international, as the central place in research and development base of Fukui prefecture, and to utilize the outcome in our decommissioning to the technical development effectively. This report consists of presentation paper are "The current status of Fugen decommissioning", "Regarding dismantling and decontamination of steam drums", "Knowledge of radiation management in dismantling contaminated equipment", "Achievements and considerations for identifying and separating contaminated parts of nonradioactive waste" and "Regarding technology development plans for nuclear reactor dismantling" which is presented in the 41st Technical Special Committee on Fugen Decommissioning.
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
Times Cited Count:1 Percentile:23.17(Physics, Nuclear)Kaneko, Koji; Tabata, Chihiro; Hagihara, Masato; Yamauchi, Hiroki; Oba, Yojiro; Kumada, Takayuki; Kubota, Masato; Kojima, Yuki*; Nabatame, Nozomi; Sasaki, Miki; et al.
JPS Conference Proceedings (Internet), 41, p.011015_1 - 011015_6, 2024/03
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
Times Cited Count:2 Percentile:58.81(Physics, Nuclear)no abstracts in English
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.
Okuda, Yukihiko; Kang, Z.; 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
The outer walls of nuclear facility buildings consist of reinforced concrete (RC) panels. When a projectile collides with a nuclear facility building, local damages such as penetration, scabbing, and perforation can occur in the RC panels. Numerical simulation using finite element analysis (FEA) is generally employed to assess these damage conditions. However, the impact analysis by FEA modelled with continuum elements is difficult to address phenomena such as scattering fragments of concrete because the elements deletion method for large deformation is used to prevent interruption of numerical calculations. Recently, a numerical method known as Smooth Particles Hydrodynamics (SPH), one of the particle methods, has been employed to address discontinuous phenomena. In this paper, we focus on the scabbing damages to RC panels and report on the findings obtained through the validation of the numerical analysis using the SPH method.
Yamashita, Takayuki*; Harjo, S.; Kawasaki, Takuro; Morooka, Satoshi; Gong, W.; Fujii, Hidetoshi*; Tomota, Yo*
ISIJ International, 64(2), p.192 - 201, 2024/01
Times Cited Count:0 Percentile:0.00(Metallurgy & Metallurgical Engineering)Ota, Kyugo*; Matsumoto, Yuji*; Watabe, Yuki*; Kaneko, Koji; Tabata, Chihiro; Haga, Yoshinori
New Physics; Sae Mulli, 73(12), p.1170 - 1173, 2023/12
We have performed the neutron scattering study of antiferromagnet UPt
Al
with the honeycomb lattice to determine the magnetic structure. U
Pt
Al
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.
Toyota, Kodai; Imagawa, Yuya; Onizawa, Takashi; Kato, Shoichi; Furuya, Yoshiyuki*
Nihon Kikai Gakkai Rombunshu (Internet), 89(928), p.23-00206_1 - 23-00206_15, 2023/12
In order to design fast reactors, it is necessary to consider high cycle fatigue of structural materials up to 110
cycles; to evaluate high cycle fatigue at 1
10
cycles, it is necessary to develop a best-fit fatigue curve applicable up to 1
10
cycles. In this study, high cycle fatigue tests were conducted under strain-controlled conditions and ultrasonic fatigue tests were also conducted to develop a high cycle fatigue evaluation method for Mod.9Cr-1Mo steel, which is a candidate material for fast reactor structural materials. Based on the test results, the best-fit fatigue curves were extended and the applicability of the JSME best-fit fatigue curves up to 1
10
cycles was verified.
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
Times Cited Count:4 Percentile:40.37(Physics, Multidisciplinary)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.
Yamada, Ryohei*; Tamakuma, Yuki*; Kuwata, Haruka*; Saigusa, Yumi*; Watanabe, Yuki; Hirota, Seiko*; Jin, Q.*; Cai, Y.*
Hoken Butsuri (Internet), 58(3), p.169 - 177, 2023/11
no abstracts in English
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
Times Cited Count:1 Percentile:18.07(Optics)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.
Li, P. J.*; Beaumel, D.*; Lee, J.*; Assi, M.*; Chen, S.*; Franchoo, S.*; Gibelin, J.*; Hammache, F.*; Harada, T.*; Kanada-En'yo, Yoshiko*; et al.
Physical Review Letters, 131(21), p.212501_1 - 212501_7, 2023/11
Times Cited Count:21 Percentile:93.59(Physics, Multidisciplinary)The cluster structure of the neutron-rich isotope Be has been probed via the (
) reaction. The triple differential cross-section was extracted and compared to distorted-wave impulse approximation reaction calculations performed in a microscopic framework using the Tohsaki-Horiuchi-Schuck-R
pke wave function and the wave function deduced from Antisymmetrized Molecular Dynamics calculations. The remarkable agreement between calculated and measured cross-sections in both shape and magnitude validates the description of the
Be ground-state as a rather compact nuclear molecule.