Some considerations of the use of concrete for radioactive waste repositories

Abstract

This paper describes three particular investigations which have been undertaken in relation to the potential use of concrete as a backfill material for deep radioactive waste repositories. The first of these investigations considered some of the consequences of backfilling around heat generating wastes, with particular regard to identifying appropriate computer models and obtaining an indication of the temperature generated stresses in a hypothetical situation. The second study was concerned with the possibility of forming the concrete from grouted pre-packed aggregate which was thought to be less susceptible to creep and shrinkage than conventional concretes. No such benefits were identified. In the third study samples of concretes up to 2500 years old were obtained and subjected to chemical and physical examination to identify the characteristics which had contributed to the long life of these materials. An understanding of these mechanics may provide reassurance about the future reliability of equivalent current materials.