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Mochizuki, Masahito*; Katsuyama, Jinya; Ihara, Ryohei*; Mori, Hiroaki*; Mikami, Yoshiki*; Onizawa, Kunio
Proceedings of 2009 ASME Pressure Vessels and Piping Division Conference (PVP 2009) (CD-ROM), 8 Pages, 2009/07
Stress corrosion cracking near the welded zone of core internals and recirculation piping has been observed at the surface where tensile residual stress exists due to welding and/or surface machining. The tensile residual stress in the inner surface of the pipe is caused by welding and surface machining. In this study, Vickers hardness and residual stress distributions at the inner surface of butt-weld joint with surface-machining before and after welding were experimentally evaluated. Welding simulation has been performed to study the distribution and the occurrence mechanism of tensile residual stress. It was shown that residual stress and hardness distributions by welding after surface machining depended on the welding condition and that the effect of surface machining disappeared. Residual stress distributions due to surface-finishing after welding were also found to depend on surface-machining condition but the region was limited to a thin area of surface hardened layer.
Ishikawa, Satoru*; Arao, Tomohito*; Baba, Koji*; Mori, Shinsuke*; Nishizawa, Naoko*; Nakanishi, Hiromi*; Yoshihara, Ryohei; Hase, Yoshihiro
JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 80, 2008/11
no abstracts in English
Watanabe, Masayuki; Mirvaliev, R.*; Tachimori, Shoichi; Takeshita, Kenji*; Nakano, Yoshio*; Morikawa, Koshi*; Chikazawa, Takahiro*; Mori, Ryohei*
Solvent Extraction and Ion Exchange, 22(3), p.377 - 390, 2004/06
Times Cited Count:32 Percentile:65.8(Chemistry, Multidisciplinary)The synergistic extraction with N,N,N',N'-tetrakis(2-methylpyridyl)-ethylenediamine (TPEN) and di(2-ethylhexyl)phosphoric acid (D2EHPA) demonstrates a good selectivity for Am(III) over macro amount of Ln(III) in 1-octanol. The maximum apparent separation factor, which is defined as the ratio of the distribution ratio of Am(III) to that of Eu(III), is ca. 80 while the molar fraction between D2EHPA and TPEN is 2.0. This ratio is corresponding to the result of the spectrophotometric titration, which indicates that TPEN and D2EHPA form an aggregate in 1-octanol and two D2EHPA molecules coordinate to Eu(III) TPEN complex, [Eu(TPEN)]. In the present study, the association of D2EHPA and TPEN is one of the most important factors for the synergistic extraction and the complexation of TPEN and D2EHPA with Eu(III).
Watanabe, Masayuki; Mirvaliev, R.*; Tachimori, Shoichi; Takeshita, Kenji*; Nakano, Yoshio*; Morikawa, Koshi*; Mori, Ryohei*
Chemistry Letters, 31(12), p.1230 - 1231, 2002/12
Times Cited Count:40 Percentile:73.32(Chemistry, Multidisciplinary)Encapsulative semi-podand type ligand, N, N, N', N' #8211; tetrakis(2-methylpyridyl)ethylenediamine (TPEN) gives good selectivity of Am(III) over trivalent lanthanide by solvent extraction. This is the first robust extraction system which can separate Am(III) from trivalent lanthanide.
Yamada, Ryohei; Hashimoto, Hiroki*; Tamakuma, Yuki*; Omori, Yasutaka*; Hosoda, Masahiro*; Akata, Naofumi*; Uchiyama, Rei; Nakada, Akira; Endo, Michitaka*; Imajo, Yusuke*; et al.
no journal, ,
no abstracts in English