The Slovenian project assessed the LILW inventory and considered the implications of Waste Acceptance Criteria for the conditioning and packaging of wastes, together with how this could affect the choice of a preferred siting and disposal concept. Several waste treatment and packaging options were considered in an attempt to identify optimised containment characteristics that would result in safe disposal, taking into account the cost-benefit of alternative safety measures. Performance assessment models for each design and siting option were developed. Modelling of releases from the engineered containment system was undertaken using AMBER. Water fluxes from groundwater flow modelling of each degradation level were then incorporated into the AMBER models for further radionuclide transport calculations appropriate to each packing solution. The approach proved to be highly flexible, transparent and effective in terms of calculation time. Results demonstrated that all waste streams could be accepted at the preferred site with the surface repository option, under the condition that all decommissioning waste would be grouted into high integrity containers. The use of high integrity containers is also recommended for all other waste streams.

Furthermore, as part of a preliminary postclosure safety assessment of permanent repository concepts for LILW in Canada, the following four geotechnically feasible disposal options were analysed using AMBER:

• Covered Above Grade Concrete Vault on sand;
• Covered Above Grade Concrete Vault on till;
• Deep Rock Cavern Vault in shale; and
• Deep Rock Cavern Vault in limestone.

Image courtesy of NDA RWM.