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Saito, Shigeru; Suzuki, Kazuhiro; Hatakeyama, Yuichi; Suzuki, Miho; Dai, Y.*
Journal of Nuclear Materials, 534, p.152146_1 - 152146_16, 2020/06
Times Cited Count:1 Percentile:11.8(Materials Science, Multidisciplinary)A post-irradiation examination (PIE) was performed on the tensile specimens prepared from the MEGAPIE (MEGAwatt Pilot Experiment) target which were irradiated in flowing lead-bismuth eutectic (LBE). Thicknesses of the specimens were over two times larger than that of the standard specimen. The PIE revealed that the T91 specimens showed a 1.5-2.0 times larger total elongation (TE) compared to the literature values for a specimen with standard t/w (ratio of thickness to width). It could be suggested that the t/w and TE were strongly correlated. Then, we tried to investigate the effects of the t/w on the TE by comparing unirradiated specimens. We found that there was no t/w dependence on the strength and uniform elongation. On the other hand, the TE increases with increasing t/w. Based on the experimental data, we correlated the TE with various specimens t/w to estimate appropriate TE values, including that for the standard specimen.
Wakai, Eiichi; Matsukawa, Shingo; Yamamoto, Toshio*; Kato, Yoshiaki; Takada, Fumiki; Sugimoto, Masayoshi; Jitsukawa, Shiro
Materials Transactions, 45(8), p.2641 - 2643, 2004/08
Times Cited Count:6 Percentile:41.09(Materials Science, Multidisciplinary)no abstracts in English
Yamaki, Tetsuya; Ito, Hisayoshi; Matsubara, Masakazu*; Abe, Hiroaki*; Asai, Keisuke*
Transactions of the Materials Research Society of Japan, 28(3), p.879 - 882, 2003/10
Titanium oxide nanoparticles were formed by pulsed laser ablation of a TiO rutile pellet with a KrF excimer laser ( = 248 nm). The ablation was performed in atmospheres of Ar and O at total pressures ranging from 0.2 and 10 Torr. At a higher pressure than 1 Torr, Ti in the nanoparticles had an oxidation state of 4+ to form TiO. According to the X-ray diffraction analyses, the nanopartiles were found to contain both the anatase and rutile phases, which crystallized through extremely energetic, non-equilibrium reactions in an ablation plume. In contrast, at pressures of 0.2 and 0.5 Torr, the nanoparticles were composed of dominant TiO with a small amount of a less oxidized phase such as TiO. The important result is that the XRD patterns of the samples prepared at 1 and 5 Torr showed the different anatase-to-rutile ratio of the peak intensities. This indicates that the weight fraction of the rutile/anatase crystalline phases can be controlled by the ambient gas pressure.
Wakai, Eiichi; Ezawa, Tadashi*; Imamura, Junko*; Takenaka, Tsuyoshi*; Tanabe, Tetsuo*; Oshima, Ryuichiro*
Journal of Nuclear Materials, 307-311(Part.1), p.367 - 373, 2002/12
Times Cited Count:29 Percentile:84.85(Materials Science, Multidisciplinary)no abstracts in English
Yamaki, Tetsuya; Shinohara, Ryuji*; Asai, Keisuke*
Thin Solid Films, 393(1-2), p.154 - 160, 2001/08
Times Cited Count:10 Percentile:50.69(Materials Science, Multidisciplinary)no abstracts in English
*
JNC TJ9400 2000-007, 46 Pages, 2000/03
For fission cross section and prompt fission neutron spectrum, which largely influence core characteristics of a fast reactor, we have performed experimental and analytical studies for developing an advanced technique to measure absolute fission cross section and neutron fission spectrum for actinide nuclides such as Np237. As the results, we could develop an advanced technique, which combines a normalization technique for the well-known differential cross section and a correction method by a Monte-Carlo code for sample effects. This advanced technique accurately provides both absolute fission cross section and prompt fission neutron spectrum individually. By employing this technique, in this study, we have measured for three actinides (Np, Th and U), then, have obtained the fission cross sections and fission spectrum parameter data for those nuclides. Furthermore, we have also performed an analytical study to examine sensitivity of fission spectrum parameter to core multiplication factor by using the standard calculation code for a first reactor.
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Journal of Nuclear Materials, 132, p.92 - 94, 1985/00
Times Cited Count:0 Percentile:0.4(Materials Science, Multidisciplinary)no abstracts in English
Yoneda, Yasuhiro; Kunisada, Ryoichi*; Chikada, Tsukasa*; Ueno, Shintaro*; Fujii, Ichiro*; Wada, Satoshi*
no journal, ,
High-energy X-ray diffraction measurements were performed to analyze KNbO nanocrystals. We used KNbO nanocrystals with cubic shape. Moreover, these nanocrystals have cubic structure owing to their small crystal size. Therefore, these nanocrystals are ideal for applying the Scherrer's equation. Crystal-growth mechanism was considered with the crystal size obtained by the Scherrer's equation. It was found the growth mechanism of KNbO by comparing the crystal size and average structure obtained by Rietveld analysis and coherent size obtained by atomic pair-distribution function method.