Modeling Alloy 22 general corrosion in the Yucca Mountain nuclear waste repository

Abstract

How would you… …describe the overall signifi cance of this paper? This paper describes the general corrosion of Alloy 22 under the Yucca Mountain environment. Long-term modeling and data analysis for Alloy 22 are presented to estimate the performance of the Alloy 22 waste package outer barrier in the repository. …describe this work to a materials science and engineering professional with no experience in your technical specialty? Relatively few studies focus on longterm general corrosion behavior of highly corrosion-resistant Ni-Cr-Mo alloys such as Alloy 22. This work presents Alloy 22 general corrosion data analysis and modeling for longterm performance prediction. …describe this work to a layperson? General corrosion is an important mode of degradation of alloys. This paper summarizes the Alloy 22 general corrosion testing and modeling that has been undertaken in support of the Yucca Mountain Project. Longterm modeling and data analysis for Alloy 22 are presented. This paper presents the general corrosion model used by the Yucca Mountain Project to account for general corrosion degradation of the Alloy 22 waste package outer barrier. The general corrosion rates were determined from mass-loss measurements of specimens exposed to repository-relevant solutions at 60°C and 90°C for about fi ve years. An Alloy 22 general corrosion temperature dependence was obtained from short-term polarization resistance measurements and found to be consistent with values quoted in the literature. Uncertainty in mass-loss data and model fi tting was evaluated and incorporated into the resultant Alloy 22 general corrosion model.

Progress in corrosion protection as a requirement for technical progress

“…A well‐known problem is, of course, the storage of nuclear waste that has to be kept away from the environment for at least 10 000 years. Since no experience with corrosion exists over such a long period of time, prediction methods have to be developed, which are also a part of the research in the United States and other highly industrialized countries 24–27. Nevertheless, this kind of corrosion assessment requires prediction over several orders of magnitudes, which from a scientific point of view can be associated with high risk.…”