Microbiologically Influenced Corrosion of Nuclear Waste Containers

Abstract

Microbiologically influenced corrosion (MIC) is one of a num-ber 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 decisiontree 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.

Bacterial Attachment and Initiation of Biofilms on the Surface of Copper Containing Stainless Steel

“…6) Microbially influenced corrosion is henceforth serious problems in the world and attracts the attentions of scientists and engineers. 7) Microbiologically influenced corrosion was found even on stainless steels, [8][9][10][11] which have good corrosion resistance in moderate environments and therefore have a wide range of applications in industries. Corrosion failure of type 304L stainless steels under a mild environment, i.e.…”

Environmental Degradation of Engineered Barrier Materials in Nuclear Waste Repositories

“…MIC could affect the three corrosion processes mentioned above mainly by changing the environment in the vicinity of the containers. King provided a decision tree approach to determine if MIC would be an important factor in determining the lifetime of the containers [29]. Figure 36.1 shows schematically how metallurgical and environmental factors may control the occurrence of the three main corrosion processes.…”

Modelling Groundwater Contamination Above High-Level Nuclear-Waste Repositories in Salt, Granitoid and Clay

“…The experimentally derived diffusion coefficient of aqueous sulphide in bentonite is approximately 7 x 10 -8 cm 2 /s (King & Stroes-Gascoyne, 1995;King et al, 2002). The groundwater of the envisaged repositories in Finland, Sweden and Canada has sulphide concentrations in the range from <3 x 10 -7 to 3 x 10 -5 mol/L.…”