Chemical conditions in a repository

The chemical conditions in a repository for nuclear waste in granitic bedrock are of major importance for the integrity of the barriers in the repository, especially for the corrosion of waste canisters and dissolution of radionuclides. The chemistry of the nearfield, i.. the pH, Eh and potential complexing ions, also affects the solubility and chemical form of radionuclides and the transport in the repository and the bedrock. The purpose of this study was to establish the effect of the materials introduced into the repository, such as construction materials, buffer and backfill materials and waste canisters, upon the chemical conditions in a repository for low and intermediate level reactor waste and spent fuel in granitic bedrock. The approach was through experimental studies of near field components, e.g. the wasteform, backfill on groundwater chemistry and theoretical studies, including modelling, which aimed at studying the evolution of the chemistry over longer time scales