Microbiologically Influenced Corrosion of Nuclear Waste Containers

Abstract

Microbiologically influenced corrosion (MIC) is one of a number of threats to the long-term integrity of nuclear waste containers. As such, the potential for, and extent of, MIC must be assessed and suitable models developed for predicting the long-term behavior of the container. There are two broad approaches to assessing the threat posed by MIC; first, to determine whether the environment will support microbial activity and, if so, where and when it will occur, and second, to estimate the maximum amount of damage that could occur if microbial activity in the repository is possible. A decision-tree approach is used to present evidence for both of these approaches and to decide whether MIC is a significant threat to the integrity of the container. Examples are provided from various international nuclear waste management programs. It is concluded that microbial effects will not compromise the safety of the overall disposal system because they will not lead to either early container failures or to a large number of simultaneous failures, both factors that can lead to an increase in the peak dose.