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Yoshida, Hiroyuki; Suzuki, Takayuki*; Nabeshima, Kunihiko; Takase, Kazuyuki
Nihon Kikai Gakkai Kanto Shibu Dai-15-Ki Sokai Koenkai Koen Rombunshu, p.105 - 106, 2009/03
no abstracts in English
Suzuki, Takayuki*; Yoshida, Hiroyuki; Takase, Kazuyuki
Nihon Kikai Gakkai Kanto Shibu Dai-15-Ki Sokai Koenkai Koen Rombunshu, p.103 - 104, 2009/03
no abstracts in English
Ioka, Ikuo; Suzuki, Jun; Maruyama, Nobutoshi*; Kiuchi, Kiyoshi; Nakayama, Jumpei
no journal, ,
Optimization of composition for high Cr-W-Si Ni base alloy has been studied to apply to a nitric acid with high oxidation-reduction potential of advanced reprocessing plants. The corrosion resistance of the Ni base alloy is superior to that of conventional stainless steels. In addition, The Ni base alloy has an excellent resistance of weld crack and ability of plastic deformation caused by extra high purity (EHP) refining technology. However, the Ni base alloy has a technical limitation in hot working and welding for practical use. Several Ni base EHP alloys with different content of Si and W were manufactured to choose an optimum composition range without losing corrosion resistance. High strain rate tensile tests at high temperature, corrosion tests and weldability tests were carried out to examine the optimum composition range of Ni base EHP alloy.
Ioka, Ikuo; Yonekawa, Kazuo; Maruyama, Nobutoshi*; Kiuchi, Kiyoshi; Nakayama, Jumpei
no journal, ,
Nb-W binary alloy which is superior to current zirconium for corrosion and cracking in severer environment is developed for advanced reprocessing plants. Ductility of Nb-W binary alloy is improved by an application of extra high purity (EHP) refining technology, but mechanical strength deteriorates. A ductile-brittle transition temperature (DBTT) of Nb-W binary alloy rises, though the increase in W improves mechanical strength. DBTT of the weld tends to be high in comparison with the base metal, and a rise of DBTT by increase in W becomes the problem. Nb-W EHP alloys with different content of W were manufactured to choose an optimum composition range. Tensile, corrosion and Charpy impact tests were carried out to examine the optimum composition range of Nb-W EHP alloy.
Naoe, Takashi; Wakui, Takashi; Yamaguchi, Yoshihito; Futakawa, Masatoshi
no journal, ,
Liquid mercury was selected as a target material of the high-power spallation neutron source. The target vessel which embrace the mercury receives repeated stress due to the pressure wave and the thermal stress. Then, it is concerned about the Liquid Metal Embrittlement (LME) of the target vessel. In this study, fatigue tests in mercury were performed to investigate the compatibility between mercury and austenitic stainless steel. Furthermore, the effect of liquid metal on fatigue crack propagation was examined by the fracture surface analysis and the opening distance measurement.
Yoshiie, Toshimasa*; Sato, Koichi*; Xu, Q.*; Futakawa, Masatoshi; Naoe, Takashi; Kawai, Masayoshi*
no journal, ,
A mercury target in high-power spallation neutron sources is subjected to the pressure wave caused by proton beam. Subsequent formation and collapse of cavitation bubbles lead to cavitation damage on the target vessel, especially the beam window. The cavitation damage in Ni and austenitic stainless steel SUS304SS were studied by using MIMTM (electro-Magnetic IMpact Testing Machine) developed to simulate the damage. The existence of dislocations, stacking fault tetrahedra and vacancies was detected by positron annihilation lifetime measurement in Ni and non-cellar dislocation structures were observed by transmission electron microscopy in Ni and SUS316SS. High density of twins was also observed in SUS304SS. These results were compared with those of high speed compression test by using high speed projectile and proved that the cavitation damage by MIMTM corresponded to high speed deformation.
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.
Sato, Hidetomo*; Nakano, Hiromasa*; Yokota, Hitoshi*; Suzuki, Tetsuya*; Maekawa, Katsuhiro*; Kurata, Yuji
no journal, ,
Liquid lead-bismuth is a candidate material used for accelerator driven systems and fast reactors. One of difficulties to apply Pb-Bi to nuclear systems is the corrosiveness of liquid Pb-Bi to structural steels. Recently, an Al alloy coating technique using Al and Ti powders was developed. In this study, type 316 stainless steel was coated with Al-Ti-Fe alloy layer to enhance corrosion resistance in liquid lead-bismuth. As a result of the corrosion test of the Al alloy coated specimens in liquid lead-bismuth, it was found that the coated layer exhibited good corrosion resistance to lead-bismuth.
Wakui, Takashi; Teshigawara, Makoto; Naoe, Takashi; Kogawa, Hiroyuki; Haga, Katsuhiro; Futakawa, Masatoshi
no journal, ,
The liquid mercury target system for the MW-class pulse spallation neutron source was installed at the material and life science experimental facility (MLF) in J-PARC. The laser Doppler vibrometer system was installed as diagnostic system on the structural integrity of the mercury target. Vibration measurements on the liquid mercury target vessel were carried out using this system. The amplitude of the first peak increase with an increase of the proton beam power. The delay time until the vibration starts in experimental results is longer than in analytical results. The slope of the regression line indicating the relationship between the delay time and the injection position of the proton beam is higher than that estimated by the sound velocity of the mercury. That is, the sound velocity of the mercury in the mercury vessel is predicted to be lower than that calculated using material constants.