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Sasaki, Yoshito; Onuki, Toshihiko; Itabashi, Yasuhiro*; Shigihara, Takashi*; Kurikami, Hiroshi; Amamiya, Hiroki*; Niizato, Tadafumi
Chemosphere, 379, p.144431_1 - 144431_8, 2025/06
no abstracts in English
Sonehara, Masateru; Okano, Yasushi; Uchibori, Akihiro; Oki, Hiroshi*
Journal of Nuclear Science and Technology, 62(5), p.403 - 414, 2025/05
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)For sodium-cooled fast reactors, understanding sodium combustion behaviour is crucial for managing sodium leakage accidents. In this study, we perform benchmark analyses of the Sandia National Laboratories (SNL) T3 experiment using the multi-dimensional thermal hydraulic code AQUA-SF. Conducted in an enclosed space with a large vessel volume of 100 m
and a sodium mass flow rate of 1 kg/s, the experiment highlighted the multi-dimensional effects of local temperature increase shortly after sodium injection. This study aims to extend the capabilities of AQUA-SF by focusing on the simulation of these multi-dimensional temperature variations, in particular the formation of high temperature regions at the bottom of the vessel. The proposed models include the temporary stopping of sodium droplet ignition and spray combustion of sodium splash on the floor. Furthermore, it has been shown that additional heat source near the floor is essential to enhance the reproduction of the high temperature region at the bottom. Therefore, case studies including sensitivity analyses of spray cone angle and prolonged combustion of droplets on the floor are conducted. This comprehensive approach provides valuable insights into the dynamics of sodium combustion and safety measures in sodium-cooled fast reactors.
Hirata, Yoshinobu*; Nakagawa, Hiroshi; Yamauchi, Hiroki; Kaneko, Koji; Hagihara, Masato; Yamaguchi, Hideyuki*; Imaizumi, Teppei*; Nishizu, Takahisa*
International Journal of Biological Macromolecules, 306, p.141668_1 - 141668_7, 2025/03
Times Cited Count：0 Percentile：0.00(Biochemistry & Molecular Biology)We used quasi-elastic neutron scattering (QENS) to investigate the effect of the ratio of water to rice on the molecular dynamics of cooked rice starch during retrogradation. X-ray diffraction and differential scanning calorimetric measurements revealed that the degree of recrystallization and change in enthalpy were smaller with an increase in the amount of water added for cooking rice, whereas little difference in the crystallinity of the gelatinized rice starch was detected. The QENS measurements determined that the elastic incoherent structure factor (EISF) values of gelatinized samples were smaller with an increase in the amount of water added for cooking rice, indicating that the molecular dynamics of gelatinized rice starch with higher added water content were spatially more extended.
Shimomura, Koichiro*; Koda, Akihiro*; Pant, A. D.*; Sunagawa, Hikaru*; Fujimori, Hiroshi*; Umegaki, Izumi*; Nakamura, Jumpei*; Fujihara, Masayoshi; Tampo, Motonobu*; Kawamura, Naritoshi*; et al.
Interactions (Internet), 245(1), p.31_1 - 31_6, 2024/12
C and 500CTakagi, Honoka*; Yabutsuka, Takeshi*; Hayashida, Hirotoshi*; Song, F.; Kai, Tetsuya; Shinohara, Takenao; Kurita, Keisuke; Iikura, Hiroshi; Yamamoto, Norio*; Nakajima, Minoru*; et al.
Solid State Ionics, 417, p.116716_1 - 116716_7, 2024/12
Times Cited Count：2 Percentile：26.43(Chemistry, Physical)
= 0.01-600C, 
= 1-3000 bars, 
= 0.35-1.1 g cm
, and 
= 0
Walker, C. S.*; Arthur, R. C.*; Anraku, Sohtaro; Sasamoto, Hiroshi; Mihara, Morihiro
Applied Geochemistry, 175, p.106086_1 - 106086_17, 2024/11
Times Cited Count：0 Percentile：0.00(Geochemistry & Geophysics)The thermodynamic properties and revised Helgeson-Kirkham-Flowers equation of state (r-H-K-F EoS) parameters of the hydrated (Si(OH)
(aq), SiO(OH)
and SiO
(OH)
) and fictive dehydrated (SiO(aq), HSiO and SiO) monomeric silicon species are used extensively to describe the pH, composition, temperature, and pressure dependence of formation/breakdown reactions of all silicon-bearing compounds globally. Experimental log10 equilbrium constant, K values describing the formation reactions of the hydrated and dehydrated monomeric silicon species were therefore compiled from the literature, extrapolated to zero ionic strength by specific ion interaction theory as required and used to derive their thermodynamic properties and r-H-K-F EoS parameters. Consideration of all formation reactions in the same study provides a collective, internally consistent update to the thermodynamic properties and r-H-K-F EoS parameters of the monomeric silicon species that can provide a satisfactory match to the experimental log10 K values at = 0.01-600C, = 1-3000 bars, = 0.35-1.1 g cm, and zero ionic strength. These temperature and pressure limits comfortably bracket t=0.01-100C and P =1-270 bars relecant to the geological disposal of radioactive wastes at depths of up to 1 km.
Ogawa, Tatsuhiko; Hirata, Yuho; Matsuya, Yusuke; Kai, Takeshi; Sato, Tatsuhiko; Iwamoto, Yosuke; Hashimoto, Shintaro; Furuta, Takuya; Abe, Shinichiro; Matsuda, Norihiro; et al.
EPJ Nuclear Sciences & Technologies (Internet), 10, p.13_1 - 13_8, 2024/11
The latest updates on PHITS, a versatile radiation transport code, focusing specifically on track-structure models are presented. Track structure calculations are methods used to simulate the movement of charged particles while explicitly considering each atomic reaction. Initially developed for radiation biology, these calculation methods aimed to analyze the radiation-induced damage to DNA and chromosomes. Several track-structure calculation models, including PHITS-ETS, PHITS-ETS for Si, PHITS-KURBUC, ETSART, and ITSART, have been developed and implemented to PHITS. These models allow users to study the behavior of various particles at the nano-scale across a wide range of materials. Furthermore, potential applications of track-structure calculations have also been proposed so far. This collection of track-structure calculation models, which encompasses diverse conditions, opens up new avenues for research in the field of radiation effects.
Yoshimune, Wataru*; Higuchi, Yuki*; Song, F.; Hibi, Shogo*; Matsumoto, Yoshihiro*; Hayashida, Hirotoshi*; Nozaki, Hiroshi*; Shinohara, Takenao; Kato, Satoru*
Physical Chemistry Chemical Physics, 26(47), p.29466 - 29474, 2024/11
Times Cited Count：2 Percentile：56.45(Chemistry, Physical)Kowatari, Munehiko*; Yoshitomi, Hiroshi; Tani, Kotaro*; Tanimura, Yoshihiko; Kurihara, Osamu*
Radiation Protection Dosimetry, 200(16-18), p.1574 - 1579, 2024/11
Times Cited Count：0 Percentile：0.00(Environmental Sciences)
Tc separation/concentration technology from 
Mo by (n, 
) method, 2Fujita, Yoshitaka; Hu, X.*; Yang, Y.*; Kitagawa, Taiga*; Fujihara, Yasuyuki*; Yoshinaga, Hisao*; Hori, Junichi*; Do, T. M. D.*; Suzuki, Tatsuya*; Suematsu, Hisayuki*; et al.
KURNS Progress Report 2023, P. 122, 2024/07
no abstracts in English
Morito, Makoto*; Fujii, Shun*; Yoshimura, Koki*; Sanada, Yukihisa; Baba, Shoichiro*; Matsunaga, Hiroshi*; Mori, Takami*; Sato, Keiichiro*; Tahara, Junichiro*
Proceedings of 34th International Ocean and Polar Engineering Conference (ISOPE-2024), p.3754 - 3761, 2024/06
This study proposes a method that combines sliding mode control and neural networks as a control method for unmanned surface vehicle to measure radiation in submarine soil. Sliding mode control is used as the base of control input, and corrective inputs are added using a neural network controller so that one of the parameters of sliding mode control, 
, and its rate of change are reduced. After producing a control system using this method, we conducted simulation tests and sea area tests to evaluate whether the survey could be conducted using this method.
Usui, Yoshiya*; Ueshima, Makoto*; Hase, Hideaki*; Ichihara, Hiroshi*; Aizawa, Koki*; Koyama, Takao*; Sakanaka, Shinya*; Ogawa, Tsutomu*; Yamaya, Yusuke*; Nishitani, Tadashi*; et al.
Journal of Geophysical Research; Solid Earth, 129(5), p.e2023JB028522_1 - e2023JB028522_22, 2024/05
Times Cited Count：2 Percentile：60.18(Geochemistry & Geophysics)We elucidated the crustal heterogeneities beneath a strain concentration area on the back-arc side of the northeastern Japan Arc based on electrical resistivity. By deploying magnetotelluric surveys, we revealed the three-dimensional electrical resistivity structure in the crust, suggesting the coexistence of two types of strain-concentration mechanisms in the strain-concentration area. The shallow conductive layers and lower-crustal conductors appear to act as low-elastic-modulus and low-viscosity areas, respectively, and are responsible for the strain concentration. We found a spatial correlation between the edges of the lower-crustal conductors and the epicenters of large intraplate earthquakes. Weak shear zones in the conductive lower crust may cause stress loading on faults in the brittle upper crust, resulting in large earthquakes. We also identified vertical conductors ranging from the lower crust to Quaternary volcanoes, which may indicate fluid paths to these volcanoes.
Higuchi, Yuki*; Yoshimune, Wataru*; Kato, Satoru*; Hibi, Shogo*; Setoyama, Daigo*; Isegawa, Kazuhisa*; Matsumoto, Yoshihiro*; Hayashida, Hirotoshi*; Nozaki, Hiroshi*; Harada, Masashi*; et al.
Communications Engineering (Internet), 3, p.33_1 - 33_7, 2024/02
Sato, Tatsuhiko; Iwamoto, Yosuke; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Kai, Takeshi; Matsuya, Yusuke; Matsuda, Norihiro; Hirata, Yuho; et al.
Journal of Nuclear Science and Technology, 61(1), p.127 - 135, 2024/01
Times Cited Count：144 Percentile：99.97(Nuclear Science & Technology)The Particle and Heavy Ion Transport code System (PHITS) is a general-purpose Monte Carlo radiation transport code that can simulate the behavior of most particle species with energies up to 1 TeV (per nucleon for ions). Its new version, PHITS3.31, was recently developed and released to the public. In the new version, the compatibility with high-energy nuclear data libraries and the algorithm of the track-structure modes have been improved. In this paper, we summarize the upgraded features of PHITS3.31 with respect to the physics models, utility functions, and application software introduced since the release of PHITS3.02 in 2017.
Hanamachi, Yuji*; Walker, C.*; Sasamoto, Hiroshi; Mihara, Morihiro
NIMS Bisai Kozo Kaiseki Purattofuomu Riyo Hokokusho (Internet), 2 Pages, 2023/12
A High-volume Fly ash Silica fume Cement (HFSC) has been considered as the use of concrete support of drift in deep disposal of radioactive wastes. JAEA has been carried out experiments and modeling studies to evaluate chemical stability of C-A-S-H gel synthesized which would be believed as the dominant component of the HFSC. For the modeling purpose, it is necessary to evaluate the chemical composition both of C-A-S-H gel synthesized and accompanied minerals in the experiment. In the year of 2020, 
Al and 
Si NMR measurement were performed to identify Al and Si distribution in the sample and chemical composition of C-A-S-H gel was derived. However, it was impossible to derive the C-A-S-H gel composition having the expected Al/Si molar ratio since there were several accompanied minerals produced in the experiment due to the short term of immersion. This time similar approach to derive C-A-S-H gel composition is adopted using NMR measurement for the sample of longer time (6 months).
Nozaki, Hiroshi*; Kondo, Hiroki*; Shinohara, Takenao; Setoyama, Daigo*; Matsumoto, Yoshihiro*; Sasaki, Tsuyoshi*; Isegawa, Kazuhisa*; Hayashida, Hirotoshi*
Scientific Reports (Internet), 13, p.22082_1 - 22082_8, 2023/12
Times Cited Count：3 Percentile：21.01(Multidisciplinary Sciences)
Pb and 
Bi in proton-induced reactions near 100 MeVIwamoto, Hiroki; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Ishi, Yoshihiro*; Uesugi, Tomonori*; Yashima, Hiroshi*; Nishio, Katsuhisa; Sugihara, Kenta*; 
elik, Y.*; et al.
Nuclear Instruments and Methods in Physics Research B, 544, p.165107_1 - 165107_15, 2023/11
Times Cited Count：4 Percentile：68.76(Instruments & Instrumentation)The lack of double-differential cross-section (DDX) data for neutron production below the incident proton energy of 200 MeV hinders the validation of spallation models in technical applications, such as research and development of accelerator-driven systems (ADSs). The present study aims to obtain experimental DDX data for ADS spallation target materials in this energy region and identify issues related to the spallation models by comparing them with the analytical predictions. The DDXs for the (
) reactions of Pb and Bi in the 100-MeV region were measured over an angular range of 30 to 150 using the time-of-flight method. The measurements were conducted at Kyoto University utilizing the FFAG accelerator. The DDXs obtained were compared with calculation results from Monte Carlo-based spallation models and the evaluated nuclear data library, JENDL-5. Comparison between the measured DDX and analytical values based on the spallation models and evaluated nuclear data library indicated that, in general, the CEM03.03 model demonstrated the closest match to the experimental values. Additionally, the comparison highlighted several issues that need to be addressed in order to improve the reproducibility of the proton-induced neutron-production DDX in the 100 MeV region by these spallation models and evaluated nuclear data library.
Kurita, Keisuke; Iikura, Hiroshi; Tsuchikawa, Yusuke; Kai, Tetsuya; Shinohara, Takenao; Odaira, Naoya*; Ito, Daisuke*; Saito, Yasushi*; Matsubayashi, Masahito
Journal of Physics; Conference Series, 2605, p.012005_1 - 012005_6, 2023/10
The Japan Research Ractor-3 (JRR-3) is operation resumed on February 26, 2021, and the shared use was also restarted in July, 2021. With the resumption of JRR-3 operation, two imaging facilities called TNRF and CNRF have also resumed their utilization. In this presentation, we report the details of these two neutron facilities.
symmetry for anisotropic 
hybridization in the heavy-fermion superconductor CeNiGeFujiwara, Hidenori*; Nakatani, Yasuhiro*; Aratani, Hidekazu*; Kanai-Nakata, Yuina*; Yamagami, Kohei*; Hamamoto, Satoru*; Kiss, Takayuki*; Yamasaki, Atsushi*; Higashiya, Atsushi*; Imada, Shin*; et al.
Physical Review B, 108(16), p.165121_1 - 165121_10, 2023/10
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)Sonehara, Masateru; Okano, Yasushi; Uchibori, Akihiro; Aoyagi, Mitsuhiro; Oki, Hiroshi*
Dai-27-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 4 Pages, 2023/09
An analysis code AQUA-SF has been developed to evaluate the effects of sodium combustion in three dimensions, which enables more detailed elucidation of sodium combustion phenomena and evaluation of the effectiveness of safety measures. In this paper, we examine the multidimensional effects of spray combustion for the SNL-T3 test as a benchmark analysis. In order to simulate the decrease of pressure and the temperature rise near the floor during the test, a new model is developed to take into account temporal cessation of sodium ignition, increased drag coefficient due to droplet deformation and liquid splash effect due to collision between the jet stream and the floor surface, and the results are compared with the test measurements.
