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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.
Tran Duy, T.*; Sawada, Shinichi; Hasegawa, Shin; Yoshimura, Kimio; Oba, Yojiro*; Onuma, Masato*; Katsumura, Yosuke*; Maekawa, Yasunari
Macromolecules, 47(7), p.2373 - 2383, 2014/04
Times Cited Count:27 Percentile:70.31(Polymer Science)The hierarchical structures of graft-type ETFE-based polymer electrolyte membranes (ETFE-PEMs) were investigated using small- and ultrasmall-angle X-ray cattering experiments. The ETFE-PEMs with IECs 2.4 mmol/g possessed conducting graft domains around lamellar crystals, with a d-spacing of 21.8-29.1 nm, and oriented crystallites with short and long correlation distances of 218-320 and 903-1124 nm, respectively. The membranes with IECs 2.7 mmol/g showed a new phase of crystallite network domains with a d-range of 225-256 nm, indicating a phase transition from oriented crystallite to crystallite network structures in the IEC range of 2.4-2.7 mmol/g. Noted that for the ETFE-PEMs with high IECs higher conductivity at 30% RH and compatible tensile strengths at 100% RH and 80 C, compared with Nafion, originated from the well-interconnected ion channels around the crystallites and the remaining lamellar crystals and crystallites, respectively.
Mimura, Kojiro*; Hosokawa, Shinya*; Happo, Naohisa*; Hu, W.; Hayashi, Koichi*; Wakita, Kazuki*; Ishii, Hirofumi*; Yoshimura, Masato*; Jeyakanthan, J.*; Mamedov, N.*
e-Journal of Surface Science and Nanotechnology (Internet), 9, p.273 - 276, 2011/07
Hosokawa, Shinya*; Happo, Naohisa*; Hayashi, Koichi*; Mimura, Kojiro*; Wakita, Kazuki*; Hu, W.; Ishii, Hirofumi*; Yoshimura, Masato*; Jeyakanthan, J.*; Mamedov, N.*
Japanese Journal of Applied Physics, 50(5), p.05FC06_1 - 05FC06_2, 2011/05
Times Cited Count:7 Percentile:31.34(Physics, Applied)Nagashima, Yoshihiko*; Hoshino, Katsumichi; Nagaoka, Kenichi*; Shinohara, Koji; Fujisawa, Akihide*; Uehara, Kazuya; Kusama, Yoshinori; Ida, Katsumi*; Yoshimura, Yasuo*; Okamura, Shoichi*; et al.
Plasma and Fusion Research (Internet), 1(9), p.041_1 - 041_15, 2006/09
Nonlinear processes between meso-scale structures and turbulent fluctuations in the edge region of the toroidal plasmas were studied using the bispectrum analysis. In the JFT-2M tokamak, divertor plasmas were investigated as well as the limiter plasmas, and the amplitude and phase of the bispectrum function of the potential fluctuation were found to be consistent with an analysis of the drift wave-zonal flow system. In the CHS machine, the edge plasmas during the H-mode were investigated. It was found that the edge potential begins to decrease before the decrease of the intensity of the deuterium line (by about 30ms), and the edge fluctuations are found to be composed of low frequency MHD fluctuations, drift wave like broad band electrostatic fluctuations and high frequency electromagnetic fluctuations. Nonlinear coupling between the MHD fluctuations and the electrostatic fluctuations or the electromagnetic fluctuations were found for the first time.
Nagashima, Yoshihiko*; Ito, Kimitaka*; Ito, Sanae*; Fujisawa, Akihide*; Hoshino, Katsumichi; Nagaoka, Kenichi*; Ejiri, Akira*; Takase, Yuichi*; Yagi, Masatoshi*; Shinohara, Koji; et al.
Europhysics Conference Abstracts (CD-ROM), 30I, 4 Pages, 2006/00
The results of the analyses of nonlinear processes in the plasma in JFT-2M tokamak and CHS machine are reported. In both machines, the measurements of the fluctuations were done by electrostatic probes. The obtained bicoherence and biphase from the potential data in JFT-2M were found to be close to the values obtained from a theoretical model of the interaction of the zonal flow and the drift wave turbulence. Therefore the experimentally obtained nonlinear interaction is considered to be that interaction of the zonal flow and the drift wave turbulence. By the analysis of the CHS H-mode plasma, a marked nonlinear interaction was found between a characteristic MHD magnetic fluctuation and density turbulence. By analysing the cross bispectrum of the density fluctuation and the potential fluctuation, it was found that the fluctuating particle flux is affected by the MHD oscillation. As stated above, we progressed in the investigation of the nonlinear processes of the edge plasmas.
Yashima, Masatomo*; Hirose, Teruo*; Katano, Susumu; Suzuki, Yasuo*; Kakihana, Masato*; Yoshimura, Masahiro*
Physical Review B, 51(13), p.8018 - 8025, 1995/04
Times Cited Count:115 Percentile:97.2(Materials Science, Multidisciplinary)no abstracts in English
Nagashima, Yoshihiko*; Hoshino, Katsumichi; Shinohara, Koji; Uehara, Kazuya; Kusama, Yoshinori; Nagaoka, Kenichi*; Fujisawa, Akihide*; Ida, Katsumi*; Yoshimura, Yasuo*; Okamura, Shoichi*; et al.
no journal, ,
We present an invited talk on the experimental study of the nonlinear interaction processes of the edge plasma turbulence studied in the JFT-2M tokamak machine of JAEA and in the CHS helical machine of the NIFS. We made a progress in understanding the nonlinear interaction of the drift wave turbulence and the zonal flow by measuring the potential fluctuations and density fluctuations by the measurement of the electrostatic probes. We found that the measured indices such as the bicoherence or the biphase are consistent with the results of a theoretical study of the drift-wave-zonal-flow system for the first time. We also made the convergence characteristic of these indices clear against the realization numbers for the first time. The study progresses the understanding of the plasma turbulence and structural formation in the plasma, and the results contributes much to the understanding of the transport process in the plasma.
Takayama, Reona*; Oe, Kazuhiro*; Komori, Yukiko*; Fujisawa, Hiroyuki*; Kuriyama, Ai*; Kikutani, Yuki*; Kikunaga, Hidetoshi*; Kasamatsu, Yoshitaka*; Yoshimura, Takashi*; Takahashi, Naruto*; et al.
no journal, ,
The extraction behavior of trivalent actinides (Am, Cm, Cf, Es, and Fm) into di(2-ethylhexyl)phosphoric acid, HDEHP, in benzene from HNO was studied together with lanthanides. The extraction constants, values, of lanthanides, Am, Cm, Cf, and Es were determined by a batch method using stable lanthanide isotopes and radiotracers of Am, Cm, Cf, and Es, respectively, while that of Fm was measured with Fm which was produced in the U(O,4n) reaction and was on-line supplied by a gas-jet method at the AVF cyclotron of RCNP, Osaka University. The values were determined by the slope analysis for the variation of the distribution ratio as a function of the concentration of HDEHP. We found that the of Fm is smaller than that of Dy in spite of the similar ionic radii while those of other actinides are almost the same as those of each lanthanide with a similar ionic radius.
Tran, D. T.; Sawada, Shinichi; Hasegawa, Shin; Yoshimura, Kimio; Oba, Yojiro*; Onuma, Masato*; Katsumura, Yosuke*; Maekawa, Yasunari
no journal, ,
Fundamental understanding of the structure-property relationship of PEM is prerequisite for proper material design to improve PEM performance. In this work, we studied hierarchical structures of ETFE-based graft-type polymer electrolyte membranes using small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), and field emission scanning electron microscopy (FE-SEM). Then the relationship between hierarchical structures and fuel cell properties of ETFE-PEM was explained. The membrane possesses a shoulder peak at low q range with d-spacing of 36.1 nm and new peak at high q range with d-spacing of 1.48 nm. Such peaks should be originated from lamellar structure and correlation distance of the sulfo groups in poly(styrene sulfonic acid) grafts, respectively. In FE-SEM images, the clear phase separation between hydrophobic and hydrophilic domains was observed.
Tran, D. T.; Sawada, Shinichi; Hasegawa, Shin; Yoshimura, Kimio; Oba, Yojiro*; Onuma, Masato*; Katsumura, Yosuke*; Maekawa, Yasunari
no journal, ,
Fundamental understanding of the structure-property relationship of PEM is prerequisite for a material design satisfying PEM performance requirement. Therefore, the hierarchical structures of ETFE-PEMs were characterized using wide q observation in small angle X-ray scattering (SAXS) by comparing those of precursor original ETFE and polystyrene-grafted film (grafted ETFE). ETFE-PEM possesses three distinct structures: (1) Graft polymer domains with d-spacing of 390 nm, which should act as ion conducting layer; (2) Lamellar structures with d-spacing of 29 nm; (3) An inner structure of graft domains with d-spacing of 1.5 nm correspond to correlation distances of sulfonic acid group. The ion-conducting layers and lamellar structures with d-spacing of 390 nm and 29 nm in ETFE-PEM can be confirmed by atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM), respectively.
Iwata, Yoshihiro; Miyabe, Masabumi; Wakaida, Ikuo; Yoshimura, Shoki*; Matsumura, Tamaki*; Morita, Masato*; Sakamoto, Tetsuo*
no journal, ,
Information on the elemental and isotopic compositions of fuel debris is essential for the decommissioning of TEPCO's Fukushima Daiichi Nuclear Power Station. In this study, we have developed a double-resonance ionization scheme for highly sensitive and accurate isotope analysis of neodymium (Nd), which is a burnup indicator.