An Assessment of the Long-Term Durability of Concrete in Radioactive Waste Repositories

Abstract

A preliminary assessment of the long-term durability of concrete in a repository sited in clay is presented. The assessment is based on recorded experience of concrete structures and both field and laboratory studies. It is also supported by results of the examination of a concrete sample which had been buried in clay for 43 years.The enoineering lifetime of a 1 m thick reinforced concrete slab, with one face in contact with clay, and the way in which pH in the repository as a whole is likely to vary with time have both been estimated from available data. The estimates indicate that engineering lifetimes of about 10³ years are expected (providing that sulphate resisting cement is used) and that pH is likely to remain above 10.5 for about 10⁶ years.