International technical evaluation of alteration mechanisms relevant to glass corrosion – SCK•CEN report: Final report for IAEA CRP 1813 on processing technologies for high level waste, formulation of matri

To gain a fundamental understanding of the dissolution rate law of vitrified waste, six nations (USA, Japan, France, Belgium, UK, Germany) have undertaken collaborative research activities into the mechanisms controlling the long-term corrosion of glass. The collaborating laboratories all conduct fundamental and/or applied research using modern materials science techniques. In order to provide a common benchmark to relate results from different groups using various experimental tools, multi-scale probes, and modeling approaches, it was decided to formulate a common glass that will be studied by all collaborators. This glass is called the International Simple Glass (ISG). The contribution of four of the participating nations (USA, Japan, France, Belgium) is reported for IAEA CRP1813 on processing technologies for high level waste, formulation of matrices and characterization of waste forms. This report describes the work carried out by the Belgian Nuclear Research Centre in this collaborative research project. It was performed as part of the programme of the Belgian Agency for Radioactive Waste and Enriched Fissile Materials (NIRAS/ONDRAF) on the geological disposal of high level/long-lived radioactive waste. The tests performed by the Belgian Nuclear Research Centre have focused on the pH conditions that are expected in the Belgian Supercontainer design for HLW disposal. In this design, the near fiels surrounding the glass will be conditioned by the presence of concrete made with Ordinary Portland Cement.