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Soma, Yasutaka; Komatsu, Atsushi; Ueno, Fumiyoshi
Zairyo To Kankyo, 67(9), p.381 - 385, 2018/09
In-situ measurement of electrical conductivity of solution within crevice of SUS316L stainless steel in 288
C water has been conducted with newly developed electrochemical sensor system. The sensor measures local electrical conductivity of crevice solution beneath the electrode (
) with electrochemical impedance method. The sensors were installed at different positions within tapered crevice of SUS316L stainless steel. The crevice specimen with the sensors were immerged into 288C, 8 MPa, pure oxygen saturated high purity water for 100 h. at a position with crevice gap of 
59.3
m was 8-11S/cm, least deviate from conductivity of 288C pure water (4.4S/cm) and no localized corrosion occurred. On the contrary, at a position with crevice gap of 4.4m increased with time and showed maximum value of 1600S/cm at 70 h. Localized corrosion occurred in the vicinity of this position. Thermodynamic equilibrium calculation showed of 1600S/cm being equivalent to pH of 3 to 3.7. It can be concluded that acidification occurred in tight crevice even under high purity bulk water and resulted in localized corrosion.
Soma, Yasutaka; Ueno, Fumiyoshi
Zairyo To Kankyo, 67(5), p.222 - 228, 2018/05
Localized corrosion in crevice of SUS316 stainless steel after immersion in 288C high purity water with dissolved oxygen concentration of 32 ppm for 100 h was analyzed. Two different types of localized corrosion initiated on grain boundary and inclusions. The former initiated on grain boundary and oxide grown into grain matrix. The oxidized area showed duplex structure composed of microcrystalline FeCr
O
and island-shaped residual metals. The latter initiated on inclusions containing Ca and S and microcrystalline FeCrO grown into metal matrix. These localized corrosion occurred selectively in oxygen depleted area indicated formation of macroscopic corrosion cell with the corroded area as anode and surrounding oxygenated area as cathode.
Takeuchi, Tomoaki; Nakano, Hiroko; Uehara, Toshiaki; Tsuchiya, Kunihiko
Nuclear Materials and Energy (Internet), 9, p.451 - 454, 2016/12
Times Cited Count：1 Percentile：84.04(Nuclear Science & Technology)no abstracts in English
Soma, Yasutaka; Kato, Chiaki; Ueno, Fumiyoshi
Fushoku Boshoku Kyokai Dai-63-Kai Zairyo To Kankyo Toronkai Koenshu, p.253 - 256, 2016/10
Contribution of corrosion to advance of stress corrosion cracking (SCC) of stainless steel in high temperature water must be assessed because serious corrosion can be found within SCC of light water reactors. The corrosion took the form of both intergranular and grain-matrix attack indicate aggressive corrosion condition was formed in the crevice of the SCC. We have investigated the crevice environment electrochemically and found that local electrical conductivity of the crevice solution at satisfactory narrow crevice gap having more than 100 times higher than that of bulk solution. In this research we assessed effect of cyclic deaerated and aerated bulk solution to the crevice environment. The result showed that electrical conductivity of the crevice solution under the deaerated bulk solution increased more than 10times by injection of pure oxygen suggest that the dissolved oxygen caused aggressive corrosion condition within the crevice.
Nakano, Hiroko; Uehara, Toshiaki; Takeuchi, Tomoaki; Shibata, Hiroshi; Nakamura, Jinichi; Matsui, Yoshinori; Tsuchiya, Kunihiko
JAEA-Technology 2015-049, 61 Pages, 2016/03
JAEA-Technology-2015-049.pdf:14.7MB
In Japan Atomic Energy Agency, we started a research and development so as to monitor the Nuclear Plant Facilities situations during a severe accident, such as a radiation-resistant monitoring camera under a severe accident, a radiation resistant in-water transmission system for conveying the information in-core and a heat-resistant signal cable. As part of advance in a heat-resistant signal cable, we maintained to ex-core high-temperature and pressure water loop test equipment which can be simulated conditions of BWRs and PWRs for evaluation reliability and property of construction sheath materials. This equipment consists of Autoclave, water conditioning tank, water pump, high-pressure metering pump, preheater, heat exchanger and pure water purification equipment. This report describes the basic design and the results of performance tests of construction machinery and tools of ex-core high-temperature and pressure water loop test equipment.
Kimura, Takaumi; Kirishima, Akira*; Arisaka, Makoto
Kidorui, (47), p.43 - 56, 2005/11
no abstracts in English
Tsukada, Takashi; Miwa, Yukio; Ugachi, Hirokazu; Matsui, Yoshinori; Itabashi, Yukio; Nagata, Nobuaki*; Dozaki, Koji*
Proceedings of International Conference on Water Chemistry of Nuclear Reactor Systems (CD-ROM), 5 Pages, 2004/10
IASCC initiation and propagation tests will be performed on the per-irradiated specimen in the Japan Materials Testing Reactor (JMTR). Since in core, the radiolysis of water causes a generation of various kind of radical species and some oxidizing species such as hydrogen peroxide, the water chemistry in irradiation capsules must be assessed by measurements of the electrochemical corrosion potential (ECP). For the in-core measurement of ECP in JMTR, we fabricated and tested the Fe/Fe
O type ECP sensor. After the fabrication, the function of each sensor was examined in high temperature water by out-of-core thermal cycling and high temperature holding tests.
Kimura, Takaumi; Nagaishi, Ryuji; Arisaka, Makoto*; Ozaki, Takuo; Yoshida, Zenko
Radiochimica Acta, 90(9-11), p.715 - 719, 2002/11
Times Cited Count：15 Percentile：29.73(Chemistry, Inorganic & Nuclear)no abstracts in English
Tsukada, Takashi
Nippon Yosetsu Kyokai "Genshiryoku Kozo Kiki No Zairyo, Sekkei, Seko, Kensa Ni Kansuru Koshukai" Tekisuto, 40 Pages, 2002/00
no abstracts in English
Tsukada, Takashi; Ebine, Noriya
Nippon AEM Gakkai-Shi, 9(2), p.171 - 177, 2001/06
no abstracts in English
Ouchi, Nobuo; Kusano, Joichi; Akaoka, Nobuo*; Mizumoto, Motoharu; Inoue, Hitoshi*; Noguchi, Shuichi*; Saito, Kenji*; Takeda, O.*; Murai, T.*; Kijima, Y.*; et al.
KEK Proceedings 99-25, p.33 - 37, 2000/02
no abstracts in English
Tsukada, Takashi
Proceedings of Seminar on Water Chemistry of Nuclear Reactor Systems '99, p.26 - 32, 1999/00
no abstracts in English
Tsukada, Takashi
JAERI-Research 98-007, 187 Pages, 1998/03
JAERI-Research-98-007.pdf:17.46MB
no abstracts in English
*; Hasegawa, Kazuo; Honda, Yoichiro*; Kusano, Joichi; Mizumoto, Motoharu; Mukugi, Ken*; Ouchi, Nobuo; Inoue, Hitoshi*; Noguchi, Shuichi*; Saito, Kenji*
Proceedings of 6th European Particle Accelerator Conference (EPAC98) (CD-ROM), p.734 - 736, 1998/01
no abstracts in English
Matsui, Yoshinori; Niimi, Motoji; Hoshiya, Taiji; Tsukada, Takashi; Tsuji, Hirokazu
Journal of Nuclear Materials, 258-263, p.378 - 382, 1998/00
Times Cited Count：0 Percentile：100(Materials Science, Multidisciplinary)no abstracts in English
Akaoka, Nobuo*; Kusano, Joichi; Ouchi, Nobuo; Mizumoto, Motoharu; Takeda, O.*; Noguchi, Shuichi*; Saito, Kenji*; *; *; *
Proceedings of 23rd Linear Accelerator Meeting in Japan, p.289 - 291, 1998/00
no abstracts in English
Kusano, Joichi; Ouchi, Nobuo; Akaoka, Nobuo*; *; Noguchi, Shuichi*; Mukugi, Ken*; Hasegawa, Kazuo; Mizumoto, Motoharu
Proc. of 11th Symp. on Accelerator Sci. and Technol., p.240 - 242, 1997/00
no abstracts in English
Tsukada, Takashi; Miwa, Yukio; Nakajima, Hajime; *
Proc. of 8th Int. Symp. on Environ. Degradation of Materials in Nuclear Power Systems - Water Reactors, 2, p.795 - 802, 1997/00
no abstracts in English
Tsukada, Takashi; Miwa, Yukio; Shindo, Masami
Fourth Japan-China Symp. on Mater. for Advanced Energy Systems and Fission and Fusion Engineering '96, 0, p.223 - 227, 1996/00
no abstracts in English
Tsukada, Takashi; Miwa, Yukio; ; Tsuji, Hirokazu; Nakajima, Hajime
Proc. of 2nd Japan-Central Europe Joint Workshop on Modelling of Materials and Combustion, 0, p.80 - 83, 1996/00
no abstracts in English
