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duplex stainless steel weld overlay cladding of light-water reactor pressure vessel steelsMatsukawa, Yoshitaka*; Kakubo, Yuta*; Nozawa, Yasuko*; Toyama, Takeshi*; Nagai, Yasuyoshi*; Takeuchi, Tomoaki; Yamaguchi, Yoshihito; Katsuyama, Jinya; Nishiyama, Yutaka
no journal, ,
Crystal structure change and composition change of G-phase (Ni
Si
Mn
) precipitates in a duplex stainless steel welded on an RPV steel were analyzed by transmission electron microscopy combined with atom-probe tomography. Based on TEM crystallographic analysis data and atom-probe composition analysis data, together with simulation results of electron diffraction patterns, it was found that those precipitates turned G-phase in structure-wise before they turned stoichiometric composition.
Suzudo, Tomoaki; Yamaguchi, Masatake; Tsuru, Tomohito
no journal, ,
He-embrittlement is a major concern for the structural material of future fusion devices, such as the first wall of the blanket, and the understanding of its mechanism is critical for the material design. Although previous studies using the first principles calculations reveal that He weakens the strength of some grain boundaries, a countless types of grain boundaries exist and in principle it is not realistic to analyze all of those types. Consequently, it is important to retrieve common features over the different grain boundaries. In the present study, we analyzed He-embrittlement of plenty types of grain boundaries of alpha-Fe and found that the loss of grain-boundary strength roughly scales with He concentration at each grain boundary regardless of the grain boundary type.
Otsuka, Satoshi; Yano, Yasuhide; Tanno, Takashi; Kaito, Takeji; Tanaka, Kenya
no journal, ,
In the neutron irradiation test of 9Cr-ODS steel using a Russian experimental fast reactor BOR-60, anomalous microstructure change had occurred. This report describes the high-temperature thermal aging test results of defective 9Cr-ODS steel containing metallic Cr inclusions, which was carried out with the intention of reproducing the anomalous microstructure change in the BOR-60 irradiation test.
and ZrNishida, Yuki*; Tsukada, Yuki*; Koyama, Toshiyuki*; Kurata, Masaki
no journal, ,
In a severe accident of light water reactors, interaction layers are formed between UO pellet and Zry cladding in the beginning stage. The melting temperature of a part of layers are rather lower than that of Zry cladding. In the present study, a base MPFM model was developed for understanding solid-solid diffusion and layer formation between UO and Zr, which are major constituents of pellet and cladding, respectively. Then, liquefaction condition of each layer was discussed using MPFM model. Model calculation indicates that meta-stable liquid phase is possibly formed in intermediate stage of mutual diffusion even at 1773 K, which is far lower than melting temperature of Zry. Also, in case of mutual diffusion between UO and Zr, spinodal separation of each phase potentially accerelates the layer formation.
CuH
(x
1)Saito, Hiroyuki; Takagi, Shigeyuki*; Endo, Naruki; Machida, Akihiko; Aoki, Katsutoshi; Orimo, Shinichi*; Katayama, Yoshinori
no journal, ,
no abstracts in English
( = Fe, Co, Ni) alloys at high pressure and temperatureEndo, Naruki; Ishikawa, Kazuhiro*; Saito, Hiroyuki; Machida, Akihiko; Katayama, Yoshinori
no journal, ,
no abstracts in English
Machida, Akihiko; Saito, Hiroyuki; Hattori, Takanori; Sano, Asami; Endo, Naruki; Watanuki, Tetsu; Katayama, Yoshinori; Aoki, Katsutoshi; Sato, Toyoto*; Matsuo, Motoaki*; et al.
no journal, ,
no abstracts in English
Yamaguchi, Masatake; Kameda, Jun*
no journal, ,
no abstracts in English