Corrosion issues of radioactive waste packages in geological disposal systems

This chapter looks at the corrosion issues of radioactive waste packages in view of their final disposal in geological repositories. First, the main waste form categories are introduced: vitrified high-level waste (HLW), spent nuclear fuel, and cemented intermediate level waste. The relation of the corrosion of these different waste forms with the geological disposal concept and with the safety assessment of the disposal site is highlighted. Next, the corrosion of the different types of waste forms, and of the metallic container for the HLW forms is discussed in terms of (1) the corrosion or dissolution processes, (2) current experimental approaches, and (3) the modelling of corrosion and lifetime predictions. One of the main challenges in this internationally-oriented research is obtaining data and reliable predictions for behaviour over long time periods, as geological disposal of these types of waste must remain safe for thousands to hundreds of thousands of years.