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Doda, Norihiro; Kato, Shinya; Hamase, Erina; Kuwagaki, Kazuki; Kikuchi, Norihiro; Ohgama, Kazuya; Yoshimura, Kazuo; Yoshikawa, Ryuji; Yokoyama, Kenji; Uwaba, Tomoyuki; et al.
Proceedings of 20th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-20) (Internet), p.946 - 959, 2023/08
An innovative design system named ARKADIA is being developed to realize the design of advanced nuclear reactors as safe, economical, and sustainable carbon-free energy sources. This paper focuses on ARKADIA-Design for design studies as a part of ARKADIA and introduces representative verification methods for numerical analysis methods of the core design. ARKADIA-Design performs core performance analysis of sodium-cooled fast reactors using a multiphysics approach that combines neutronics, thermal-hydraulics, core mechanics, and fuel pin behavior analysis codes. To confirm the validity of these analysis codes, validation matrices are identified with reference to experimental data and reliable numerical analysis results. The analysis models in these codes and the representative practices for the validation matrices are described.
Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Hatakeyama, Nozomi*; Miura, Ryuji*; Miyamoto, Naoto*; Miyamoto, Akira*; Ara, Kuniaki; Shimoyama, Kazuhito; Kato, Atsushi; Yamamoto, Tomohiko
Journal of Computer Chemistry, Japan, 21(2), p.61 - 62, 2022/00
no abstracts in English
Tsutsui, Satoshi; Higashinaka, Ryuji*; Nakamura, Raito*; Fujiwara, Kosuke*; Nakamura, Jin*; Kobayashi, Yoshio*; Ito, Takashi; Yoda, Yoshitaka*; Kato, Kazuo*; Nitta, Kiyofumi*; et al.
Hyperfine Interactions, 242(1), p.32_1 - 32_10, 2021/12
Times Cited Count:1 Percentile:84.42Hama, Katsuhiro; Mikake, Shinichiro; Ishibashi, Masayuki; Sasao, Eiji; Kuwabara, Kazumichi; Ueno, Tetsuro; Onuki, Kenji*; Beppu, Shinji; Onoe, Hironori; Takeuchi, Ryuji; et al.
JAEA-Review 2015-024, 122 Pages, 2015/11
Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technical basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase III, as the Phase II was concluded for a moment with the completion of the excavation of horizontal tunnels at GL-500m level in February 2014. This report presents the results of the investigations, construction and collaboration studies in fiscal year 2014.
Yamagishi, Isao; Nagaishi, Ryuji; Kato, Chiaki; Morita, Keisuke; Terada, Atsuhiko; Kamiji, Yu; Hino, Ryutaro; Sato, Hiroyuki; Nishihara, Kenji; Tsubata, Yasuhiro; et al.
Journal of Nuclear Science and Technology, 51(7-8), p.1044 - 1053, 2014/07
Times Cited Count:16 Percentile:76.9(Nuclear Science & Technology)For safe storage of zeolite wastes generated by treatment of radioactive saline water at the Fukushima Daiichi Nuclear Power Station, properties of the Herschelite adsorbent were studied and its adsorption vessel was evaluated for hydrogen production and corrosion. Hydrogen production depends on its water level and dissolved species because hydrogen is oxidized by radicals in water. It is possible to evaluate hydrogen production rate in Herschelite submerged in seawater or pure water by taking into account of the depth effect of the water. The reference vessel of decay heat 504 W with or without residual pure water was evaluated for the hydrogen concentration by thermal hydraulic analysis using obtained fundamental properties. Maximum hydrogen concentration was below the lower explosive limit (4 %). The steady-state corrosion potential of a stainless steel 316L increased with absorbed dose rate but its increase was repressed by the presence of Herschelite. At 750 Gy/h and 60C which were values evaluated at the bottom of the vessel of 504 W, the localized corrosion of SUS316L contacted with Herschelite would not immediately occur under 20,000 ppm of Cl concentration.
Yamagishi, Isao; Nagaishi, Ryuji; Terada, Atsuhiko; Kamiji, Yu; Kato, Chiaki; Morita, Keisuke; Nishihara, Kenji; Tsubata, Yasuhiro; Ji, W.*; Fukushima, Hisashi*; et al.
IAEA-CN-211 (Internet), 5 Pages, 2013/01
Since the accident at Fukushima Daiichi Nuclear Power Station, a large amount of radioactive contaminated water has been generated to cool damaged reactor cores. Adsorption of cesium with zeolite-like media was employed for treatment of this contaminated saline water. As spent zeolite media are highly radioactive, their safe storage is a pressing issue. Japan Atomic Energy Agency has extensively conducted R&D on the management of secondary wastes produced by the operation of the treatment system. Subjects on the safe storage of spent zeolites include the analysis of their characteristics and the evaluation of effectiveness of the present safety measures in consideration of decay heat emission and hydrogen generation by water radiolysis as well as durability of vessels exposed to saline. Preliminary results obtained are described in the present paper.
Okazaki, Ryuji*; Konczykowski, M.*; Van der Beek, C. J.*; Kato, Tomonari*; Hashimoto, Kenichiro*; Shimozawa, Masaaki*; Shishido, Hiroaki*; Yamashita, Minoru*; Ishikado, Motoyuki; Kito, Hijiri*; et al.
Physica C, 470(Suppl.1), p.S485 - S486, 2010/12
Times Cited Count:0 Percentile:0(Physics, Applied)We report the lower critical fields measurements on Fe-based oxipnictide PrFeAsO single crystals for and -planes. To avoid the difficulty of determinations due to the flux pinning, we developed a novel method using a miniature hall-sensor array which can evaluate the local magnetic induction ai each sensor position. The hall sensor which is placed on the edge of the crystal clearly resolves the first flux penetration from the Meissner state. The temperature dependence of for is well scaled by the in-plane penetration depth and is consistent with a full-gap superconducting state. The anistropy of at low temperatures is estimated to be 3, which is much smaller than of . This indicates the multiband superconductivity, in which the active bands for superconductivity are more two-dimensional.
Van der Beek, C. J.*; Rizza, G.*; Konczykowski, M.*; Fertey, P.*; Monnet, I.*; Okazaki, Ryuji*; Kato, Tomonari*; Hashimoto, Kenichiro*; Shimozawa, Masaaki*; Shishido, Hiroaki*; et al.
Physica C, 470(Suppl.1), p.S385 - S386, 2010/12
Times Cited Count:1 Percentile:6.5(Physics, Applied)Crystalline disorder in the pnictide superconductor PrFeAsO is studied using magneto-optical visualisation of flux penetration, transmission electron microscopy, and X-ray diffraction using synchrotron radiation. Critical-state like flux distributions and the magnitude and temperature dependence of the critical current demonstrate bulk vortex pinning by oxygen vacancies at all temperatures.
Kondo, Takafumi*; Asano, Akira*; Yang, J.*; Norizawa, Kimihiro*; Takahashi, Kenji*; Taguchi, Mitsumasa; Nagaishi, Ryuji; Kato, Ryuji*; Yoshida, Yoichi*
Radiation Physics and Chemistry, 78(12), p.1157 - 1160, 2009/12
Times Cited Count:28 Percentile:85.96(Chemistry, Physical)Spectrum and kinetic behavior of solvated electrons (e) in alkyl ammonium ionic liquids (ILs), DEMMA-TFSI, DEMMA-BF4, TMPA-TFSI, PP13-TFSI, P13-TFSI and P14-TFSI were investigated by pulse radiolysis method. The e in the ILs have same absorption peak at 1100 nm with a molar absorption coefficient of 1.5-2.310 dmmolcm. The reaction rate constant of e with Pyrene (Py) was 1.5-3.510 dmmols. These values were about one order of magnitude higher than that of diffusion controlled limit, which was calculated from measured viscosity. The dry electron (e) reacts with Py, and its rate constant in DEMMA-TFSI was 7.910 dmmols, three orders of magnitude higher than that of the e reactions.
Okazaki, Ryuji*; Konczykowski, M.*; Van der Beek, C. J.*; Kato, Tomonari*; Hashimoto, Kenichiro*; Shimozawa, Motoyuki*; Shishido, Hiroaki*; Yamashita, Minoru*; Ishikado, Motoyuki; Kito, Hijiri*; et al.
Physical Review B, 79(6), p.064520_1 - 064520_6, 2009/02
Times Cited Count:59 Percentile:87.81(Materials Science, Multidisciplinary)We have studied the lower critical fields H of superconducting iron oxipnictide PrFeAsO single crystals for H parallel and perpendicular to the ab-planes.
Yang, J.*; Kondo, Takafumi*; Norizawa, Kimihiro*; Nagaishi, Ryuji; Taguchi, Mitsumasa; Takahashi, Kenji*; Kato, Ryuji*; Anishchik, S. V.*; Yoshida, Yoichi*; Tagawa, Seiichi*
Radiation Physics and Chemistry, 77(10-12), p.1233 - 1238, 2008/10
Times Cited Count:25 Percentile:82.59(Chemistry, Physical)First observation of picosecond dynamics in ionic liquid of DEMMA-TFSI in radiation chemistry was reported. It is found that the electron produced by ionization is solvated to full solvation in ionic liquid with a rate constant of 3.910 s. The yield of solvated electrons in picosecond time region is 1.210 mol J. The dry electron in ionic liquid reacts rapidly with biphenyl and pyrene with a rate constant of 3.8 to 7.910 L mol s. The geminate ion recombination in n-dodecane and n-hexane was also observed by monitoring the transient absorptions at 523 nm.
Kato, Ryuji*; Yoshida, Yoichi*; Katsumura, Yosuke; Takahashi, Kenji*
Journal of Physical Chemistry B, 111(18), p.4770 - 4774, 2007/05
Times Cited Count:53 Percentile:76.58(Chemistry, Physical)Kimura, Takaumi; Nagaishi, Ryuji; Kato, Yoshiharu; Yoshida, Zenko
Journal of Alloys and Compounds, 323-324(1-4), p.164 - 168, 2001/07
Times Cited Count:50 Percentile:87.72(Chemistry, Physical)no abstracts in English
Kimura, Takaumi; Nagaishi, Ryuji; Kato, Yoshiharu; Yoshida, Zenko
Radiochimica Acta, 89(3), p.125 - 130, 2001/05
Times Cited Count:66 Percentile:96.82(Chemistry, Inorganic & Nuclear)no abstracts in English
Hosogane, Nobuyuki; Asakura, Nobuyuki; Sugie, Tatsuo; Yoshino, Ryuji; Fukuda, Takeshi; Kusama, Yoshinori; Tobita, Kenji; Ide, Shunsuke; Shimada, Michiya; Sengoku, Seio; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 75(2), p.156 - 161, 1999/02
no abstracts in English
Watashi, Katsumi; Aoto, Kazumi; Aoki, M; Komine, Ryuji; Ito, Takushi; Hasebe, Shinichi; Kato, Shoichi; Koi, Mamoru; Wada, Yusaku
PNC TN9410 93-142, 120 Pages, 1993/06
Much progress has been made in improving established creep properties of Type 316 stainless steel and to develop a new structural material named "FBR Grade Type 316 Stainless Steel", 316FR, with superior creep properties. This report includes a draft of Material Strength Standard of 316FR and its interpretation on the basis of the major result of research and development conducted so far. The draft includes identical items described in the "Standards for the Strength of Materials" for Monju, and was carefully prepared to have an identical style for convenience in design evaluation. Creep damage evaluation diagrams, which are depicted in the "Structural Design Guide for Class 1 Components of Prototype Fast Breeder Reactor for Elevated Temperature Service" (ETSDG) for individual materials, are also included in this report.
Takahashi, Kenji*; Hiejima, Yusuke*; Kato, Ryuji*; Nagaishi, Ryuji; Taguchi, Mitsumasa; Kojima, Takuji; Kondo, Takafumi*; Yang, J.*; Yoshida, Yoichi*
no journal, ,
Solvated electrons were studied using the pulse radiolysis and photo ionization methods. The Vis-NIR spectra and reactivity of the solvated electrons in ionic liquids are discussed.
Osone, Ryuji; Bucheeri, A.; Kurishita, Hiroaki*; Kato, Masahiro*; Yamasaki, Kazuhiko*; Maekawa, Katsuhiro*; Naoe, Takashi; Futakawa, Masatoshi
no journal, ,
Liquid mercury target system for high power spallation neutron sources is being developed. When high intensity proton beams are injected into the target, pressure waves are generated by the thermal shock in mercury and pitting damage will be imposed on the target vessel. Bubble injection into mercury is effective to mitigate the pressure waves. In this work, we propose a method of fabricating meso-nozzle for bubble injection. The method is based on powder metallurgy by inserting thin glass fibers into a metal powder matrix to create a green compact, followed by sintering at a temperature between the melting points of the powder and the fiber. SUS316L and molybdenum powders were used as the nozzle matrix materials. In order to investigate optimum sintering condition, experiments were performed at different combination of pressing load and sintering temperature. We found that in molybdenum high relative density and straight hole with circlar cross section were obtained.
Kondo, Takafumi*; Yang, J.*; Yoshida, Yoichi*; Nagaishi, Ryuji; Taguchi, Mitsumasa; Takahashi, Kenji*; Kato, Ryuji*
no journal, ,
The effect of the coexistence water on the solvated electrons in ammonium ionic liquids was studied by the electron pulse radiolysis method. The optical absorption band of the solvation electron decreased by coexistence of water, and new absorption band like a hydrated electron were generated in the medium wavelength region between solvated electron and hydrated electron. Furthermore, if quantity of water increase in the hydrophilic ionic liquid, it was found that the spectrum changed into the hydrated electron.