Grant: Collaborative Research and Development Grants

The present management scenario for the permanent disposal of high level nuclear waste is to bury it in sealed metallic containers buried in a deep stable geologic repository. The primary function of the waste container is to isolate the radioactive waste form from groundwater until radioactivity levels have decayed to innocuous levels. For the present thick-walled container design gamma radiation fields on the outside of the container would have a negligible influence on container corrosion. However, to overcome a number of fabrication and welding issues, thinner walled containers are being contemplated making a reassessment of the influence of gamma radiation on container corrosion a potential licensing requirement. This project addresses this issue by proposing a study of radiation effects on corrosion under simulated repository conditions, which will evolve from initially hot and dry to warm, aerated, and humid and eventually cool, aqueous and anoxic. A program of electrochemical, analytical and corrosion experiments will be employed to determine the mechanistic features of the corrosion process and to determine the evolution of corrosion damage as waste repository conditions evolve and radiation fields decay. A model will be developed to assess the extent to which the container wall can be thinned without compromising container corrosion performance.