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Sc
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O
determined by single-crystal neutron diffractionTanaka, Seiya*; Kiyanagi, Ryoji; Ishikawa, Yoshihisa*; Amako, Yasushi*; Iiyama, Taku*; Futamura, Ryusuke*; Maruyama, Kenichi*; Utsumi, Shigenori*
Physical Review Materials (Internet), 7(1), p.014403_1 - 014403_11, 2023/01
Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)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.
Shiraishi, Fumito*; Chihara, Ryoji*; Tanimoto, Risa*; Tanaka, Kazuya; Takahashi, Yoshio*
Island Arc, 31(1), p.e12448_1 - e12448_9, 2022/05
Times Cited Count：0 Percentile：0(Geosciences, Multidisciplinary)At Yunotaki Fall in north Japan, manganese-oxidizing bacteria were previously assumed to have oxidized manganese to precipitate birnessite, which relied on oxygen released from algae. However, it remained unclear whether larger-scale manganese oxide precipitation was actually occurring under light conditions. This study evaluated the contribution of indirect oxidation using microelectrodes to analyze local water chemistry, in addition to bulk water chemistry and DNA analyses. The results of this study demonstrate that low bulk pH values in the hot spring water hindered indirect oxidation despite the occurrence of active oxygenic photosynthesis and that direct oxidation by manganese-oxidizing bacteria is considered to dominate in the investigated sample.
Sc)O (0 
x 0.2) hexagonal ferriteMaruyama, Kenichi*; Tanaka, Seiya*; Kiyanagi, Ryoji; Nakao, Akiko*; Moriyama, Kentaro*; Ishikawa, Yoshihisa*; Amako, Yasushi*; Iiyama, Taku*; Futamura, Ryusuke*; Utsumi, Shigenori*; et al.
Journal of Alloys and Compounds, 892, p.162125_1 - 162125_8, 2022/02
Times Cited Count：2 Percentile：16.86(Chemistry, Physical)Sc)O single crystalsUtsumi, Shigenori*; Tanaka, Seiya*; Maruyama, Kenichi*; Amako, Yasushi*; Kiyanagi, Ryoji; Nakao, Akiko*; Moriyama, Kentaro*; Ishikawa, Yoshihisa*; 9 of others*
ACS Omega (Internet), 5(38), p.24890 - 24897, 2020/09
Times Cited Count：4 Percentile：21.18(Chemistry, Multidisciplinary)Fabricating large, high-crystalline-quality single-crystal samples of hexagonal ferrite Ba(FeSc)O is the first important step to elucidating its helimagnetic structure and developing it for further applications. In this study, single crystals of Ba(FeSc)O of various Sc concentrations 
were successfully grown by the spontaneous crystallization method using Na
O-FeO
flux. X-ray diffraction and elemental analysis revealed that the obtained crystals were composed of single-phase Ba(FeSc)O of high crystalline quality. The temperature dependence of magnetization and the magnetization curves at 77 K of the = 0.128 crystal exhibited behavior characteristics of helimagnetism. Neutron diffraction measurements of the = 0.128 crystal exhibited magnetic satellite reflection peaks below 211K, proving evidence that Ba(FeSc)O behaves as a helimagnetic material.
Ikeda, Shugo*; Kaneko, Koji; Tanaka, Yuki*; Kawasaki, Takuro; Hanashima, Takayasu*; Munakata, Koji*; Nakao, Akiko*; Kiyanagi, Ryoji; Ohara, Takashi; Mochizuki, Kensei*; et al.
Journal of the Physical Society of Japan, 89(1), p.014707_1 - 014707_7, 2020/01
Times Cited Count：1 Percentile：12.02(Physics, Multidisciplinary)Tanaka, Masaru*; Gofuku, Akio*; Ishizaka, Kaoru*; Sato, Kazuhiko; Nagahama, Yoji
JAEA-Research 2014-019, 103 Pages, 2014/12
JAEA-Research-2014-019.pdf:12.1MB
We had been conducting a research on risk perception and confidence-building among stakeholders regarding environmental remediation of Uranium mine site and disposal of industrial waste from FY 2007. FY 2011, we study how the Great East Japan Earthquake and Fukushima nuclear accident affects public risk perception. Therefore, a questionnaire survey on public risk perception of environmental remediation of Uranium mine site and disposal of the industrial waste in Okayama prefecture had been carried out. Another questionnaire survey on public risk perception of the disposal of disaster waste for residents in Okayama prefecture has been carried out. Following are some of the results: (1) For risk perception regarding environmental remediation of Uranium mine site, "knowledge of radiation" and "Concern about radioactive material" and "Information literacy" did not change significantly. Conversely trust in "Public administration" and "facility owner" and "Science and technology" was decreased significantly. (2) For risk perception regarding disaster waste, many people recognize the need for wide area disposal of disaster waste. Conversely, many residents are concerned about radioactive materials.
Tanno, Takashi; Otsuka, Satoshi; Yano, Yasuhide; Kaito, Takeji; Oba, Yojiro*; Onuma, Masato*; Koyama, Shinichi; Tanaka, Kenya
Journal of Nuclear Materials, 440(1-3), p.568 - 574, 2013/09
Times Cited Count：17 Percentile：78.22(Materials Science, Multidisciplinary)This study carried out mechanical tests and microstructure characterizations of several 9Cr and 11Cr-ODS tempered martensitic steels, and discussed the appropriate chemical composition range of 11Cr-ODS tempered martensitic steel from the viewpoint of high-temperature strength improvement. It was shown that the residual 
-ferrite fraction in 11Cr-ODS steel was successfully controlled to the same level as the 9Cr-ODS steel by selecting the matrix chemical compositions on the basis of the multi-component phase diagram. The tensile strength decreased with decreasing W content from 2.0 to 1.4 wt%. On the other hand, creep strength at 973 K did not degrade by the decreasing W content. Both tensile strength and creep strength increased with increasing population of the nano-sized oxide particles. Small angle X-ray scattering analysis revealed that titanium and excess oxygen contents were key parameters in order to improve the dispersion condition of nano-sized oxide particles.
Asakura, Nobuyuki; Shinya, Kichiro*; Tobita, Kenji; Hoshino, Kazuo; Shimizu, Katsuhiro; Uto, Hiroyasu; Someya, Yoji; Nakamura, Makoto; Ono, Noriyasu*; Kobayashi, Masahiro*; et al.
Fusion Science and Technology, 63(1T), p.70 - 75, 2013/05
no abstracts in English
Asakura, Nobuyuki; Shinya, Kichiro*; Tobita, Kenji; Hoshino, Kazuo; Shimizu, Katsuhiro; Uto, Hiroyasu; Someya, Yoji; Nakamura, Makoto; Ono, Noriyasu*; Kobayashi, Masahiro*; et al.
Fusion Science and Technology, 63(1T), p.70 - 75, 2013/05
Times Cited Count：14 Percentile：72.14(Nuclear Science & Technology)Design study of poloidal field coil (PFC) locations and current distribution for the advanced divertor in the Demo tokamak reactor was presented. Concept of the super-X divertor (SXD) for Demo reactor has an outer divertor leg longer than the conventional divertor, and it extends outboard to increase both the target wetted area and connection length to the outer target (
). Equilibrium calculation code, TOSCA, was developed by introducing two parameters, i.e. super-X null radius (
) and a ratio of the poloidal flux at the super-X null to that at the separatrix (
). Some SXD magnetic configurations with minimal number of PFCs located outside toroidal field coil (TFC) were Demonstrated. Locations of the divertor target were also investigated. It was found that the flux expansion can be increased up to 4-10 depending on the target location and , and that SXD has an advantage to increase with . Thus, the divertor plasma temperature is expected to decrease at the same upstream plasma density. On the other hand, large currents for the divertor PFCs were necessary. Other arrangements of PFCs such as (1) larger and (2) inside TFC, can reduce the PFC currents.
Tanaka, Masaru*; Gofuku, Akio*; Ishizaka, Kaoru*; Sato, Kazuhiko; Nagahama, Yoji
JAEA-Research 2012-016, 23 Pages, 2012/07
JAEA-Research-2012-016.pdf:9.41MB
Japan Atomic Energy Agency, Okayama University, Tottori University of Environmental Studies and Research Institute of Solid Waste Management Engineering had been conducting a research on risk perception and confidence-building among stakeholders regarding environmental remediation of Uranium mine site and disposal of industrial waste. Cognitive structure of public on safety for wide area disposal of disaster waste which had been generated from Iwate and Miyagi prefectures after the Great East Japan Earthquake would be important from a view of our research. Therefore, a questionnaire survey on public risk perception of the disposal of disaster waste for residents in Okayama prefecture has been carried out. The results are; (1) 93% of respondents support the local government cooperation for the disposal, (2) 87% of respondents support the acceptance and the disposal in their home town, and (3) 70% of respondents were concerned about radioactive contamination caused by the disposal.
Cheng, S.*; Tanaka, Yohei*; Gondai, Yoji*; Kai, Takayuki*; Zhang, B.*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; et al.
Journal of Nuclear Science and Technology, 48(10), p.1327 - 1336, 2011/10
Times Cited Count：27 Percentile：87.21(Nuclear Science & Technology)To clarify this behavior, a series of experiments have been performed in which nitrogen gas has been percolated uniformly through a particle bed. In these experiments, solid particles and water contained in a rectangular tank simulate respectively fuel debris and coolant. Based on the data obtained, an empirical model was developed to describe the transient variation in the bed inclination angle during the self-leveling process. Good agreement has been obtained between calculated and experimental values. Verification of the model has been confirmed through detailed analysis of the effects of experimental parameters such as particle size, particle density, and gas flow rate. Its applicability to extended conditions was further discussed by performing modeling simulations and comparing results against experimental data obtained from a larger-scale experimental system that employed a conventional boiling method.
Cheng, S.*; Hirahara, Daisuke*; Tanaka, Yohei*; Gondai, Yoji*; Zhang, B.*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; et al.
Experimental Thermal and Fluid Science, 35(2), p.405 - 415, 2011/02
Times Cited Count：30 Percentile：75.93(Thermodynamics)The current experiments were conducted under two dimensional (2D) and three dimensional (3D) conditions separately, in which water was used as liquid phase, and bubbles were generated by injecting nitrogen gas from the bottom of the viewing tank. Various particle-bed parameters were varied, including particle-bed height (from 30 mm to 200 mm), particle diameter (from 0.4 mm to 6 mm) and particle type (beads made of acrylic, glass, alumina and zirconia). Under these experimental conditions, three kinds of bubbling behavior were observed for the first time using digital image analysis methods that were further verified by quantitative detailed analysis of bubbling properties including surface bubbling frequency and surface bubble size under both 2D and 3D conditions.
Cheng, S.*; Tanaka, Yohei*; Gondai, Yoji*; Kai, Takayuki*; Zhang, B.*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; et al.
Proceedings of 7th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-7) (CD-ROM), 7 Pages, 2010/11
Cheng, S.*; Hirahara, Daisuke*; Tanaka, Yohei*; Gondai, Yoji*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu
Proceedings of 18th International Conference on Nuclear Engineering (ICONE-18) (CD-ROM), 8 Pages, 2010/05
A series of experiments on bubble behavior in a particle bed was performed to clarify three-phase flow dynamics in debris bed, which is essential in heat-removal capability, under coolant boiling conditions. The current experiment was conducted in a 2D tank. Water was used as liquid phase, while bubbles were generated by injecting nitrogen gas from the bottom of the tank. Various experimental parameters were taken, including different particle bed height, various particle diameter, different particle type, and different nitrogen gas flow rate. By using digital image analysis method, three kinds of bubble rise behavior were observed under current experimental conditions and confirmed by the quantitative detailed analysis of bubble rise properties including bubble departure frequency and bubble departure size.
Ando, Masami*; Nakata, Kiyotomo*; Ito, Mikiro*; Tanaka, Norihiko*; Koshiishi, Masato*; Obata, Ryoji*; Miwa, Yukio; Kaji, Yoshiyuki; Hayakawa, Masao*
Proceedings of 13th International Conference on Environmental Degradation of Materials in Nuclear Power Systems (CD-ROM), 16 Pages, 2007/00
Long term SCC growth tests for nuclear grade stainless steel (SUS316(NG)) were conducted in a simulated BWR environment using specimens taken from mock-up PLR piping weld joints to obtain the crack growth rate (CGR) of the hardened heat affected zone due to weld shrinkage around weld, in order to develop the CGR curve which will be used for flaw evaluation. The piping joints were made of forged and extracted materials with several welding techniques. The obtained CGRs were higher than that of solution heat treated material. The CGRs for hardened SUS316(NG) have a correlation with hardness regardless of materials and welding techniques. The CGRs increased with hardness in the range from 210 to 250 Hv. The CGR acceleration mechanism in hardened HAZ of low carbon stainless steel was estimated based on the strain distribution and the AFM image around a SCC crack tip. It was suggested that the interaction of the plastic strain gradient at a crack tip and local strain along GBs.
Otaki, Kiyoshi*; Tanaka, Yoji*; Katsurai, Kiyomichi*; Aoki, Kazuo*
JAERI-Review 2005-035, 79 Pages, 2005/09
JAERI-Review-2005-035.pdf:4.57MB
In order to collect technical information for the assessment on future nuclear power reactors and fuel cycle systems in Japan, investigation has been made on the characteristics and performance of future reactor options including reduced moderation water reactors (RMWRs) and their fuel cycle systems since the fiscal year 1998. The subjects of investigation are divided into three categories; breeder reactors and their fuel cycle, alternative to sodium-cooled FBR systems,plutonium recycling, spent fuel reprocessing and waste disposal. This report is a summary of the investigation carried out so far.
Senda, Mamoru*; Inaoka, Kyoji*; Yoshimura, Shinya*; Muramatsu, Toshiharu; Murakami, Satoshi*; Tanaka, Masaaki
JNC TY9400 2005-003, 66 Pages, 2004/12
JNC-TY9400-2005-003.pdf:7.85MB
Heat transfer experiments have been carried out in order to clarify the effect of the low-frequency fluid temperature fluctuation on the unsteady heat transfer in a channel, which is related to the thermal striping phenomena. In this study, fluid temperature fluctuation was realized by the periodic large-scale shedding vortices in the channel with a rectangular cylinder, where the hot and cold water flows into the test section from the lower and upper parts of the contraction. The frequency of fluid temperature fluctuation was controlled by changing the width-to-height ratio of the cylinder. The unsteady heat transfer coefficient of the channel wall was measured by the thin-film heat flux sensor. The experiments were made for the Reynolds number of 9000 and the Strouhal numbers ranging from about 0.16 to about 0.2. It is found that the time averaged Nusselt numbers in the fluid temperature fluctuation field are almost equal to those of the constant fluid temperature regardless of the Strouhal number under the present experimental conditions.And numerical simulation was carried out for typical experiment condition. By the numerical simulation, dominant frequency of Nusselt number fluctuation and fluid temperature fluctuation showed good agreement between experiment and calculation.
Tanimoto, Ryoji*; Kikuchi, Toshiaki*; Tanaka, Hirokazu*; Amino, Masaki*; Yanai, Minoru*
JNC TJ9420 2004-001, 258 Pages, 2004/02
JNC-TJ9420-2004-001.pdf:10.19MB
Process and layout design of external wet gelation stages in vibropacking process was examined for the feasibility study of commercialized FBR cycle system. In tbhis study, following process stages for the oxide core fuel production line were covered, that is, solidification, washing, drying, calcination, reduction, sintering stages including interim storage of sintering particles and reagent recovery stage.
Sato, Osamu; Tatematsu, Kenji; Tanaka, Yoji*
Genshiryoku eye, 47(7), p.60 - 64, 2001/07
no abstracts in English
