Analysis of dissolved hydrogen concentration utilizing of channel-flow-electrode method

Miura, Tatsuya*; Nishikata, Atsushi*; Tsuru, Toru*; Yamamoto, Masahiro; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*

Fushoku Boshoku Kyokai Dai-58-Kai Zairyo To Kankyo Toronkai Koenshu, p.15 - 16, 2011/09

There exist some equipments made of Ti or Ti-5Ta alloy in the spent nuclear fuel reprocessing plant. These equipments are investigated for failure by hydrogen embrittlement. To evaluate the stabilities of hydrogen in the solutions using at the reprocessing plant, channel-flow-ellectrode (CFE) method was utilized. The method to determine the dissolved hydrogen concentration was considered from the results of anodic polarization curves.

Investigation of the long term corrosion resistance of the overpack (Contract research)

Tachikawa, Hirokazu*; Kawakubo, Fumie*; Shimizu, Akihiko*; Shibata, Toshio*; Sugimoto, Katsuhisa*; Seo, Masahiro*; Tsuru, Toru*; Fujimoto, Shinji*; Inoue, Hiroyuki*

JAEA-Research 2006-058, 80 Pages, 2006/10

JAEA-Research-2006-058.pdf:10.86MB

The Japan Nuclear Cycle Development Institute submitted "Second Progress Report on Research and Development for the Geological Disposal of HLW in Japan" to the Japanese government. This report contains investigations of the corrosion life time of the overpack on the basis of experimental data and past research, assuming the ranging geological environment of Japan. However some subjects, such as the behavior of the overpack under high pH conditions and the behavior of the engineering barrier with change of near-field environmental condition with time for promoting reliability have still been left. To take into account these conditions, expert committee composed of metal corrosion science experts were established in the Nuclear Safety Research Association and past research outcomes and the theory of safety assessment were investigated from the view points of long term stability and corrosion resistance of engineering barrier.

Development of the corrosion models for the analysis of candidate materials for overpacks

Shibata, Toshio*; *; *; Tsuru, Toru*; Inoue, Hiroyuki*; *

JNC TJ8400 2002-059, 139 Pages, 2003/02

JNC-TJ8400-2002-059.pdf:7.07MB

A technical committee was organized in Japan Society of Corrosion Engineering (JSCE) to review and assess the study of overpack in JNC. The corrosion models for candidate materials for overpacks were developed in terms of corrosion science to contribute the selection of material, establishment of experimental methods and lifetime prediction of overpacks. It is expected that this report is used for the study of overpacks in the process of the research and development of high-level radioactive waste disposal.

Development of the corrosion models for the analysis of candidate materials for overpacks

Shibata, Toshio*; *; *; Tsuru, Toru*; Inoue, Hiroyuki*

JNC TJ8400 2001-008, 94 Pages, 2001/02

JNC-TJ8400-2001-008.pdf:2.05MB

A technical committee was organized in Japan Society of Corrosion Engineering to review and assess the study of overpacks in JNC. The corrosion models for candidate materials for overpaks were developed in terms of corrosion science to contribute the selection of material, establishment of experimental methods and life prediction of overpacks. It is expected that this report is used for the study of overpacks in the process of the research and development of high-level radioactive waste disposal.

The Assessment of corrosion type and corrosion rate of carbon steel in compacted bentonite

Taniguchi, Naoki; ; Kawasaki, Manabu*; Tsuru, Toru*

JNC TN8400 99-003, 88 Pages, 1999/01

JNC-TN8400-99-003.pdf:4.56MB

Carbon steel is one of the candidate materials for overpacks for high-level radioactive waste disposal in Japan. The estimation of corrosion allowance of carbon steel overpack needs to clarify the type of corrosion and the corrosion rate under repository conditions. The type of the corrosion occuring on overpacks depends on whether carbon steel is passivated or not. If carbon steel is passivated under repository conditions, localized corrosion such as pitting, crevice corrosion and stress corrosion cracking may occur under some conditions. On the other hand, if carbon steel is not passivated under repository conditions, general corrosion will occur. Passivation behavior and corrosion rate of carbon steel were investigated by electrochemical measurements under simulated repository conditions. The results of the measurements showed that carbon steel was hard to passivate in highly compacted bentonite. The immersion tests were carried out in compacted bentonite and average corrosion rates were measured from weight loss and the AC impedance of carbon steel specimens. The database of average corrosion rate were made from the data obtained by the weight loss technique. Based on the database of average corrosion rate in compacted bentonite, the relationship between average corrosion rates and test conditions were investigated. The average corrosion depth for 1000years was also estimated to be less than 5mm. In order to simulate the accumulation of corrosion products after long term, the external current were supplied to carbon steel specimens. After the formation of corrosion products, corrosion rates were measured using AC impedance technique. The results of the measurements showed that the corrosion rate of carbon steel did not increase in the presence of corrosion products formed by external current supply.

None

Tsujikawa, Shigeo*; *; *; Tsuru, Toru*; Shibata, Toshio*; *

PNC TJ1560 97-001, 210 Pages, 1997/03

PNC-TJ1560-97-001.pdf:7.28MB

None

Stochastic analysis of initiation process on pitting corrosion of stainless steels in chloride environments

; *

Proc. of the Int. Symp. on Material Chemistry in Nuclear Environment, p.497 - 506, 1992/00

no abstracts in English

Hydrogen absorption behavior of titanium alloys by cathodic polarization

Ishijima, Yasuhiro; Motooka, Takafumi; Ueno, Fumiyoshi; Yamamoto, Masahiro; Uchiyama, Gunzo; Sakai, Junichi*; Yokoyama, Kenichi*; Tada, Eiji*; Tsuru, Toru*; Nojima, Yasuo*; et al.

no journal, , 

Titanium and Ti-5mass%Ta alloy has been utilized in nuclear fuel reprocessing plant material because of its superior corrosion resistance in nitric acid solutions. However, Ti alloy have been known to high susceptibility of hydrogen embrittlement. To evaluate properties of hydrogen absorption and hydrogen embrittlement of Ti alloys, cathodic polarization tests and slow strain rate tests (SSRT) under cathodic polarization were carried out. Results show titanium hydrides covered on the surface of metals and hydrides thickness were within m. Ti and Ti-5%Ta did not show hydrogen embrittlement by SSRT under cathodic charging. These results suggested that Ti and Ti-5%Ta could absorb hydrogen. But hydrogen did not penetrate inner portion of the metals more than m in depth because titanium hydrides act as barrier of hydrogen diffusion. It is considered that retardation of hydrogen diffusion hindered hydrogen embrittlement of Ti and Ti-5%Ta alloys.