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Kaji, Yoshiyuki; Miwa, Yukio; Shibata, Akira; Nakano, Junichi; Tsukada, Takashi; Takakura, Kenichi*; Nakata, Kiyotomo*
Proceedings of 14th International Conference on Environmental degradation of Materials in Nuclear Power Systems (CD-ROM), p.1181 - 1191, 2009/08
The CGR tests of neutron irradiated Type 304 SS were conducted in BWR conditions and the results were compared with those of Type 304L and 316L SS, and following results were obtained. (1) The CGR increase with increasing neutron fluence and the power law of K on the CGR was observed above F2 neutron fluence level (1.4 dpa). The different tendency is observed between Type 304 SS and L-grade SS (Type 304L and 316L SS) with increasing neutron fluence above F3 (4.3 dpa) level. (2) The CGR of Type 304 SS is slightly small as compared with those of Type 304L and 316L SS at the same neutron fluence and shows an increasing tendency above 4 dpa and reaches to 1.0
10
m/s in 9 dpa. (3) The neutron fluence dependence on uniform elongation is different with Type 304, 304L SS and Type 316L SS, that is, the neutron fluence in which the local deformation like channeling deformation is dominant, is high for Type 316L SS.
Sato, Tomonori; Ugachi, Hirokazu; Tsukada, Takashi; Uchida, Shunsuke
Proceedings of 14th International Conference on Environmental degradation of Materials in Nuclear Power Systems (CD-ROM), p.985 - 995, 2009/08
In order to improve a theoretical prediction of flow accelerated corrosion (FAC), the individual effects of parameters which are water chemistry, material and flow dynamics should be understood. In this study, to determine the effects of minor alloying elements of carbon steel on FAC, corrosion rate of the specimens of carbon steel with various concentrations of minor alloying elements were measured. And the oxide films were examined by surface analyses techniques, e.g. Raman spectroscopy. Obtained effects of contents of Cr, Ni and Cu in carbon steel on FAC behavior are as follows; (1) FAC was suppressed for the carbon steel with more than 0.03% of Cr content. (2) FAC rate decreased as Ni content increased. (3) The hematite rich oxide was observed for Ni added carbon steel, while only magnetite was observed for Cr added one. (4) The clear effects of Cu on FAC rate was not observed.
Sato, Tomonori; Miwa, Yukio; Tsukada, Takashi; Uchida, Shunsuke
Proceedings of 14th International Conference on Environmental degradation of Materials in Nuclear Power Systems (CD-ROM), p.1041 - 1052, 2009/08
At the surface of a pure metal, a particular half cell reaction corresponding to an exposed water chemistry condition occurs. In principle, O
and HO concentrations under irradiation condition can be determined by the comparison of the redox potential responses of some kind of pure metals corresponding to exposed condition. We are developing a new array-type sensor based on this concept to determine O and HO concentrations in aqueous environment under irradiation. In order to confirm the concept of sensor, responses of the redox potentials of pure metals to the changes in O and HO concentrations were measured under non-irradiated condition. (1) The different responses of redox potentials to O and HO concentrations were obtained for the pure Fe, Cr, Zr and Pt electrodes. (2) The possibility of the concept of new array-type sensor to determine the O and HO concentrations was confirmed.