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Corrosion of Iron and Migration of Corrosion Products in Compacted Bentonite

Published online by Cambridge University Press:  15 February 2011

T. Kozaki
Affiliation:
Hokkaido Univ., Department of Nuclear Engineering, Sapporo 060, Japan
Y. Imamura
Affiliation:
Hokkaido Univ., Department of Nuclear Engineering, Sapporo 060, Japan
J. Takada
Affiliation:
Research Reactor Institute, Kyoto Univ., Kumatori-cho, Sennan-gun, Osaka, 590–04, Japan
S. Sato
Affiliation:
Hokkaido Univ., Department of Nuclear Engineering, Sapporo 060, Japan
H. Ohashi
Affiliation:
Hokkaido Univ., Department of Nuclear Engineering, Sapporo 060, Japan
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Abstract

For safety assessment of the geological disposal of the high level radioactive waste, it is necessary to study corrosion of the overpack materials and migration of the corrosion products in the compacted bentonite. In the present study, average corrosion rates of iron foil and apparent diffusion coefficients of the corrosion products were determined using a neutron- activated iron foil. The average corrosion rates were on the order of 10-6m/y, while apparent diffusion coefficients were in the range from 10-12 to 10-14m2/s. No tendency to decrease in the corrosion rates with increasing corrosion time was observed. This suggests that the iron foil corrodes under reducing condition. Asymmetric concentration profiles of iron corrosion products were obtained in some experiments. It can be considered that either cathodic or anodic reaction would dominantly occur on one side of the iron foil surfaces and that each reaction would change the pH in pore water of bentonite specimens adjacent to the iron foil surfaces.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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References

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