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Environmental Effects on Localized Corrosion of a High-Level Nuclear Waste Container Material

Published online by Cambridge University Press:  28 February 2011

N. Sridhar ,
G. Cragnolino  and
W. Machowski
N. Sridhar
Affiliation:
Southwest Research Institute, Center for Nuclear Waste Regulatory Analyses, 6220 Culebra Rd., San Antonio, TX 78228–0510
G. Cragnolino
Affiliation:
Southwest Research Institute, Center for Nuclear Waste Regulatory Analyses, 6220 Culebra Rd., San Antonio, TX 78228–0510
W. Machowski
Affiliation:
Southwest Research Institute, Center for Nuclear Waste Regulatory Analyses, 6220 Culebra Rd., San Antonio, TX 78228–0510
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Abstract

The effect of environmental variables on the localized corrosion behavior of alloy 825 is examined in this paper. Cyclic, potentiodynamic polarization tests based on a two-level, full factorial experimental design were conducted. An index incorporating both the visual and scanning electron microscope examinations of localized corrosion and the electrochemical parameters was used for the statistical analysis. The analysis showed that chloride is the single most important promoter of localized corrosion, while nitrate was the single most important inhibitor. Fluoride was a weak inhibitor, especially at low chloride levels. Sulfate was a weak promoter, especially at high chloride levels. Temperature did not have a significant effect within the chloride levels examined. Separate experiments indicated that silicon, added as metasilicate, did not have any significant effect on localized corrosion. The adverse effect of chloride was observed at concentrations as low as 100 ppm. Addition of H2O2 increased the corrosion potential of alloy 825 to a value above the repassivation potential observed in the 300 ppm chloride solution.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 212: Symposium P – Scientific Basis for Nuclear Waste Management XIV , 1990 , 269
Copyright
Copyright © Materials Research Society 1991

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References

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