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Nishioka, Tsuyoshi*; Tsuchiya, Hiroaki*; Fujimoto, Shinji*; Tachikawa, Hirokazu*; Taniguchi, Naoki
no journal, ,
no abstracts in English
irradiationYukawa, Takuji*; Inoue, Hiroyuki*; Kojima, Takao*; Tachikawa, Hirokazu*; Taniguchi, Naoki
no journal, ,
no abstracts in English
Igarashi, Takahiro; Komatsu, Atsushi; Yamamoto, Yudai*; Fushimi, Koji*; Ueno, Fumiyoshi
no journal, ,
In order to understand the hydrogen permeation behavior into the steel with solution flow, we developed a simulation model of hydrogen permeation reaction considering solution flow and conducted simulation analyses. We will discuss the effect of frequently controlled (like sine-curve) solution flow velocity on phase difference between cathode current density and permeation current density.
Soma, Yasutaka; Ueno, Fumiyoshi; Yamamoto, Masahiro
no journal, ,
Diffusion behavior of dissolved oxygen into crevice of stainless steel in high temperature is very important to understand crevice environment. In this research, we developed 3D model of crevice and using it, we carried out numerical simulation of dissolved oxygen diffusion into the crevice. The result of numerical simulation showed good agreement with experimentally obtained result.
Soma, Yasutaka; Kato, Chiaki; Ueno, Fumiyoshi; Aoki, So; Inagaki, Hiromitsu*
no journal, ,
Crevice environment was measured by electrochemical sensors in high temperature pure water. Crevice environment and surface oxide layer on the crevice surface was analyzed in terms of crevice's geometrical factors (crevice gap, g and depth, d). The results were plotted on the g-d plane. It was shown that electrical conductivity of crevice solution was very high in oxygen depleted zone and the zone shrinked with increasing crevice gap, g.
Tsukada, Takashi; Ueno, Fumiyoshi
no journal, ,
It is necessary to predict the corrosion behavior of steel materials used for primary containment vessel etc. toward a decommissioning of the reactors at Fukushima Daiichi Nuclear Power Plant. The Rotating corrosion test of carbon steel (SGV 480) specimen was conducted by alternating exposure in gas/aqueous environments, assuming the vicinity of the gas-liquid interface and inner surface of the vessel where cooling water is flowing down. As a result, an acceleration of corrosion due to the alternating exposure was observed, and it was considered that a major cause of the acceleration is due to a thin water film formed on the surface of specimen. In this presentation, the influence of rotating speed, oxygen concentration and test temperature on the corrosion behavior will be presented.
Nemoto, Yoshiyuki; Kaji, Yoshiyuki; Ogawa, Chihiro*; Nakashima, Kazuo*; Tojo, Masayuki*
no journal, ,
To cope with the hypothetical loss-of-cooling or lost-of-coolant severe accident in spent fuel pools (SFPs), it is important to understand the high temperature oxidation behavior of the Zirconium claddings exposed in the air or in the atmosphere of air/steam mixture which are presumed for the environment in spent fuel rack internal in the SFP accident. The authors have investigated the detail of high temperature oxidation behavior of the Japanese fuel cladding materials in dry air with flow rate in the hypothetical SFP accident condition, and proposed oxidation models as well. Since there is not enough knowledge about influence of air / steam mixing ratio in atmosphere on cladding oxidation in SFP accident condition, the authors conducted high temperature oxidation tests of claddings in atmosphere of air / steam mixture with flow rate of hypothetical SFP accident condition, and investigated the influence of air / steam mixing ratio on cladding oxidation behavior.