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Kasukabe, Yoshitaka*; Yamamura, Tsutomu*; Wang, J. J.*; Nishida, Shinsaku*; Yamamoto, Shunya; Yoshikawa, Masahito
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 146, 2007/02
no abstracts in English
Kasukabe, Yoshitaka*; Wang, J. J.*; Yamamura, Tsutomu*; Fujino, Yutaka*; Yamamoto, Shunya; Yoshikawa, Masahito
Materia, 45(1), p.23 - 31, 2006/01
no abstracts in English
Kasukabe, Yoshitaka*; Wang, J. J.*; Yamamura, Tsutomu*; Yamamoto, Shunya; Fujino, Yutaka*
Thin Solid Films, 464-465, p.180 - 184, 2004/10
Times Cited Count:9 Percentile:44.02(Materials Science, Multidisciplinary)no abstracts in English
Wang, J. J.*; Kasukabe, Yoshitaka*; Yamamura, Tsutomu*; Yamamoto, Shunya; Fujino, Yutaka*
Thin Solid Films, 464-465, p.175 - 179, 2004/10
Times Cited Count:1 Percentile:7.13(Materials Science, Multidisciplinary)no abstracts in English
Kawai, Masayoshi*; Furusaka, Michihiro; Li, J.-F.*; Kawasaki, Akira*; Yamamura, Tsutomu*; Mehmood, M.*; Kurishita, Hiroaki*; Kikuchi, Kenji; Takenaka, Nobuyuki*; Kiyanagi, Yoshiaki*; et al.
Proceedings of ICANS-XVI, Volume 3, p.1087 - 1096, 2003/07
In order to establish the technique fabricating a thin target slab with a real size, thin tantalum-clad tungsten slab with a hole for a thermocouple was fabricated with the high-precision machinery techniques and the HIP'ing method. The ultrasonic diagnostic showed that tantalum and tungsten bond was perfect. The HIP optimum condition was certified by means of the small punch test as already reported. The electrolytic coating technique in a molten salt was developed to make a thinner tantalum cladding on a tungsten target with a complicated shape, in order to reduce radioactivity from tantalum in an irradiated target.
Kawai, Masayoshi*; Furusaka, Michihiro*; Kikuchi, Kenji; Kurishita, Hiroaki*; Watanabe, Ryuzo*; Li, J.*; Sugimoto, Katsuhisa*; Yamamura, Tsutomu*; Hiraoka, Yutaka*; Abe, Katsunori*; et al.
Journal of Nuclear Materials, 318, p.35 - 55, 2003/05
R&D works for MW class solid target composed of tungsten to produce pulsed intense neutron source has been made in order to construct a future scattering facility. Three methods were investigated to prevent corrosion of tungsten from water; those are hipping, brazing and electric coating in molten salt bath. Hipping condition was optimized to be 1500 degree C in the previous work: here small punch test shows highest load for crack initiation of hipped materials at the boundary of W/Ta. The basic techniques for the other two methods were developed. Erosion test showed that uncovered W is susceptible of flowing water velocity. At high velocity w is easy to be eroded. For solid target design slab type and rod type targets were studied. As long as the optimized neutron performance is concerned, 1MW solid target is better than mercury target.
Mehmood, M.*; Kawaguchi, Nobuaki*; Maekawa, Hideki*; Sato, Yuzuru*; Yamamura, Tsutomu*; Kawai, Masayoshi*; Kikuchi, Kenji
Materials Transactions, 44(2), p.259 - 267, 2003/02
Times Cited Count:8 Percentile:52.13(Materials Science, Multidisciplinary)Electrochemical study has been carried out on the electro-deposition of tantalum in LiF-NaF-CaF melt containing KTaF at 700C. This has been done for determining the mechanistic features for preparing electrolytic coating of tantalum on nickel and tungsten substrates. Electro-deposition of metallic tantalum occurs primarily by electro-reduction of Ta(V). Pure metallic tantalum without any entrapped salt is successfully deposited on tungsten by galvanostatic polarization at reasonably low current densities. An additional feature on nickel is the formation of an intermetallic compound at potential 0.25V nobler than that of pure tantalum as a result of underpotential deposition of tantalum. This intermetallic compound covers the surface within a short time followed by deposition of pure tantalum, although intermetallic compound keeps growing at the interface of pure tantalum deposit and the substrate as a result of diffusion.
Hayashi, Hirokazu; Okamoto, Yoshihiro; Ogawa, Toru; Sato, Yuzuru*; Yamamura, Tsutomu*
Molten Salt Forum, 5-6, p.257 - 260, 1998/00
no abstracts in English
Myochin, Munetaka; Kofuji, Hirohide; Yamana, Hajimu*; Shirai, Osamu*; Yamamura, Tsutomu*; Umesaki, Norimasa*; Matsuura, Haruaki*; Kajinami, Akihiko*; Iwadate, Yasuhiko*; Otori, Norikazu*; et al.
no journal, ,
no abstracts in English
Kasukabe, Yoshitaka*; Yamamura, Tsutomu*; Wang, J. J.*; Nishida, Shinsaku*; Yamamoto, Shunya; Yoshikawa, Masahito
no journal, ,
no abstracts in English
Kikuchi, Kenji; Tezuka, Masao; Yamamura, Tsutomu*
no journal, ,
Wetting experiment of Pb-Bi was done in the gold image furnace by changing temperatures up to 500 degree C. A piece of solid Pb-Bi was put on the plate made of aluminum, SS316L and cast iron. Shapes are observed by microscope and data was recorded by video system. Contacting angles between Pb-Bi and metal plate are meadured. Bad wetting was described by the order of Aluminum, SS316 and Cast iron. Bad wetting makes good corrosion resistenace but bad heat transfer. Wetting property is seemed to be a parameter to be compatible with Pb-Bi.
Kawai, Masayoshi*; Futakawa, Masatoshi; Naoe, Takashi; Yamamura, Tsutomu*; Igarashi, Tadashi*
no journal, ,
A serious problem encountered when a liquid-Hg target is used for MW-class pulsed spallation neutron source is pitting damage caused to vessel walls. This pitting damage is due to the impact of cavitation-bubble collapse immediately after intense proton beams are made incident on the target. Pitting damage is thought to be as important as or more important than radiation damage in determining the life time of the target. An effectiveness of an SS/Au-double-layer-coated SS plate in reducing pitting damage is investigated. An FEM analysis reveals that the Au layer absorbs the impact from the surface plate and significantly reduced the stress on the SS substrate. SS/Au/SS specimens are fabricated by using the diffusion bonding method, and the development of pitting damage is investigated by using the MIMTM. The specimens are then analyzed by EDX for determining the thickness of the diffusion layer and by laser microscopy for detecting micro-cracks and the extent of pitting damage.
Naoe, Takashi; Futakawa, Masatoshi; Kawai, Masayoshi*; Yamamura, Tsutomu*; Igarashi, Tadashi*
no journal, ,
Mitigation of the pitting damage formation induced by the pressure wave in mercury is the most important issue to realize the MW-class spallation neutron source in J-PARC. From the viewpoint of the material approach, to mitigate the localized impact by cavitation and fatigue strength degradation due to the cavitation induced microcrack propagation, we focused on a multilayered surface treatment. Optimized multilayered surface which effectively reduced damage formation was designed by numerical calculation. Furthermore, the effects of multilayered surface treatments were experimentally evaluated by the pitting damage tests in mercury with the diffusion bonded specimen.