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Taniguchi, Naoki; Kawasaki, Manabu*; Kawakami, Susumu; Suzuki, Haruo*
JNC TN8400 2003-016, 89 Pages, 2003/03
JNC-TN8400-2003-016.pdf:1.29MB
In current repository concept of high-level radioactive disposal in soft rock system, concrete support will be emplaced around the buffer material, and groundwater pH will be increased by the contact with cement. In such condition, carbon steel overpack i
Taniguchi, Naoki; Kawasaki, Manabu*; Kawakami, Susumu; Suzuki, Haruo*
13th Asian Pacific Corrosion Control Conference (APCCC-13) (CD-ROM), H06, 8 Pages, 2003/00
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Suzuki, H.*; Hata, Yuji*; Shimada, T.*; Yamada, M.*
JNC TJ8400 2003-027, 125 Pages, 2002/03
JNC-TJ8400-2003-027.pdf:13.32MB
Laboratory scale test was conducted in order to investigate the corrosion behavior of carbon steel overpack material by simulating gaps between buffer materials, which are supposed to be generated when the buffer material is set in the disposal facility. Fifty-eight day tests were performed under various aqueous solutions in the buffer material by changing the pH of the solutions and the width of the gaps simulated. The longer period of 150 day test was also conducted, and the data on the corrosion behavior of the overpack carbon steel were obtained. Based on the test results such as corrosion rates, depth profiles, electrode potential etc. of the carbon steel test specimens, the corrosion behavior was discussed taking into account of the aqueous solution environment and the gap width of the buffer material. As a test result, the influence of the gap width of the buffer material was very little and the higher pH condition of the aqueous solutions as being contact with cement gave the higher corrosion rate to the carbon steel than the ordinary seawater. The extent of local corrosion in the present test was compared with those of the former reports. The result showed the extent of the local corrosion, a ratio of maximum and average depth, was not influenced by the width of the gap between buffer material or by the aqueous environment. All the ratios obtained in the present study were below or within the data band of the former data taken in the various aqueous conditions and natural soils, implying that the corrosion safety was preserved even when the gaps were generated between the buffer materials. Furthermore, problems of the laboratory scale test and needs for a large scale test were also discussed.
*; Hata, Yuji*; *
JNC TJ1400 2002-002, 89 Pages, 2001/08