Following the development of waste package evolution scenarios for the geological disposal of cemented intermediate-level wastes (see news story dated 15ᵗʰ August 2003), Quintessa has developed a model to investigate the importance of time dependence and heterogeneity effects on post-closure repository performance*.
The waste packages and surrounding engineered barriers were discretised and their physical and chemical evolution was modelled together with the impact on radionuclide migration. In particular, the production, release and transport of organic complexants, and the effects of their concentrations on solubility and sorption, were explicitly modelled. If you would like a copy of the report, please contact Nirex at info@nirex.co.uk.
* Modelling of Waste Package Evolution Scenarios for the Nirex Phased Repository Concept. QRS-1064B-1. David Hodgkinson, Peter Robinson and Sarah Watson, November 2002.