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Miyakawa, Susumu*; Ito, Toshimasa*; Iwahori, Keisuke*; Aoyama, Yoshihiko*; Kubo, Ryosuke*; Murata, Shinji*; Shobu, Takahisa; Shiro, Ayumi*; Kajiwara, Kentaro*
Zairyo, 69(4), p.308 - 314, 2020/04
White etching area which looks white with nital corrosive liquid may be recognized at the flaking part of a rolling bearing on which high contact stress of several GPa is applied repeatedly. Up to now, studies of white etching area of a ball have been less than studies of white etching area of inner and outer rings. In this study, as part of the flaking mechanism explication with white etching area of a ball, internal residual stress distributions of ball by using high energy white X-ray of SPring-8 (A method) and laboratorial X-ray measurement equipment (B method) were investigated. The former was modified by surface residual stress according to B method. The latter was modified by releasing stress in the form of electrolytic polishing. The results showed modified residual stress distributions almost agree qualitatively.
Maeda, Koji; Sasaki, Shinji; Kumai, Misaki; Sato, Isamu; Suto, Mitsuo; Osaka, Masahiko; Goto, Tetsuo*; Sakai, Hitoshi*; Chigira, Takayuki*; Murata, Hirotoshi*
Journal of Nuclear Science and Technology, 51(7-8), p.1006 - 1023, 2014/07
Times Cited Count：14 Percentile：72.55(Nuclear Science & Technology)Since the start of the severe accident at the Fukushima Daiichi Nuclear Power Plant in March 2011, concrete surfaces within the reactor buildings have been exposed to radioactive contaminants. Released radiation sources still remain too high to permit entry into some areas of the RBs to allow the damage to be assessed and to allow carrying out the restoration of lost safety functions, decommissioning activities, etc. In order to clarify the situation of this contamination in the RBs, 18 samples were subjected to analyses to determine the surface radionuclide concentrations and to characterize the radionuclide distributions in the samples. Decontamination tests on the sample of Unit 2 were conducted to reduce the levels of radioactivity present near the sample surface. As a result of the tests, the level of radioactivity of the sample was reduced with the removal of 97% of the contamination present near the sample surface.
Maeda, Koji; Sasaki, Shinji; Kumai, Misaki; Sato, Isamu; Osaka, Masahiko; Fukushima, Mineo; Kawatsuma, Shinji; Goto, Tetsuo*; Sakai, Hitoshi*; Chigira, Takayuki*; et al.
Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.272 - 277, 2013/09
Ohashi, Yusuke; Nakatsuka, Yoshiaki; Kawatsuma, Shinji; Hata, Haruhi; Tsunashima, Yasumichi; Murata, Masato; Tokizawa, Takayuki; Sugitsue, Noritake
no journal, ,
Sludge waste derived from research and discussion for uranium refining and conversion exclude much uranium. We must recover uranium from them from the point of view of use of resource and we dispose of residue generated by the process. We recovered uranium from real waste by water or hydrochloric acid. The dissolution rates of uranium from sludge from neutralization and NaF, filter medium, alumina, MgF
wastes were more than 99% by 2 hour 1N HCl treatment. The dissolution rate of uranium from bed material waste was more than 99% by 24h 1N HCl treatment and addition of hydrogen peroxide. The dissolution rates of NaF, filter medium waste by water treatment were 99% and 88%. From the results, we confirmed dissolution characteristics of real waste as basic data to study recovery process of uranium.
Tsunashima, Yasumichi; Nakatsuka, Yoshiaki; Kawatsuma, Shinji; Ohashi, Yusuke; Murata, Masato; Tokizawa, Takayuki; Sugitsue, Noritake; Hata, Haruhi
no journal, ,
The operation waste generated from the uranium handling facilities of the uranium conversion and uranium enrichment, etc. is called a sludge. They are assumed to be execution of the uranium collection if necessary, cement solidification, and disposal. Therefore, the examination that confirmed the range where cement solidifies was executed. The cement kind, the water cement ratio, and the sludge mixture rate were assumed to be a parameter and the solidification test was executed. The range of solidification was confirmed by the bleeding water after 24 hours had passed. The uniaxial compression was measured with cement in the solidification condition. A possibility miscible from 40wt% to about 60wt% was able to be confirmed from these examination results in the absorbent (NaF pellet and active alumina), the bed materials (no active alumina), Neutralizing precipitation.
Yaita, Yumi*; Sakai, Hitoshi*; Endo, Hiroshi*; Otani, Tomomi*; Takahashi, Yoshiaki*; Oikawa, Kageharu*; Murata, Hirotoshi*; Fukushima, Mineo; Kawatsuma, Shinji
no journal, ,
no abstracts in English
Onitsuka, Hironori*; Yano, Masahiro*; Nemoto, Yuji*; Takahashi, Takuya*; Kaneda, Masayuki*; Murata, Hirotoshi*; Chigira, Takayuki*; Fukushima, Mineo; Kawatsuma, Shinji
no journal, ,
no abstracts in English
Higashiuchi, Atsushi; Maeda, Koji; Otani, Akira; Sasaki, Shinji; Katsuyama, Kozo; Chigira, Takayuki*; Murata, Hirotoshi*
no journal, ,
no abstracts in English
Higashiuchi, Atsushi; Maeda, Koji; Sasaki, Shinji; Katsuyama, Kozo; Otani, Akira; Chigira, Takayuki*; Murata, Hirotoshi*
no journal, ,
In the development of remote decontamination technology of the reactor building, we were carried out a detailed analysis of concrete samples (hereinafter referred to as "core sample") taken from TEPCO Fukushima Daiichi Nuclear Power Station (hereinafter referred to as "1F") Unit 1 reactor building first floor south side floor, etc..
