Waste and site related issues Fredrik Vahlund SKB

Waste characteristics The consultancy report is based on the following IAEA documents: – GSG-1: “Classification of Radioactive Waste” – SSG-14: “Geological Disposal Facilities for Radioactive Waste” – Nuclear Energy Series No.NW-T-1.20: “Disposal Approaches for Long Lived Low and Intermediate Level Radioactive Waste”

Half-life and activity Is vital when determining the minimum containment period during which waste must be isolated from the environment. Is vital when determining Heat generation which may have impact on repository design. Amount of Fissile material may need to be taken into account. Co-locating LLW/ILW disposal facilities.

Chemotoxicity Potential presence of toxic or chemically hazardous substances needs to be taken into account. Groundwater protection regulation (or other regulations) must be taken into account when selecting depth and developing design.

Waste volumes HLW constitute, in general, a relatively low volume of waste. LLW (that is disposed of in near surface facilities) constitutes a high part of the total radioactive waste volume. ILW must be treated as a separate waste stream.

Waste form properties and waste conditioning With respect to the groundwater pathway, the tendency of a radionuclide to be dissolved and transported depends on: The resistance of the waste form to bio/radio/hydro degradation processes. The physical and chemical forms of released radionuclides. The chemical characteristics of the disposal environment (pH; redox; complexing ligands, colloids or corrosive species initially present or progressively induced by material degradation). The sorption characteristics of dissolved radionuclides on the adjacent engineered and natural materials.

Waste form properties related to the operational safety Other waste package characteristics that need to be taken into account; Surface dose rate, which may require additional shielding or remote handling. Potential surface contamination. Resistance of waste packages to operational hazards (drop, fire, etc).

Site related characteristics Geological properties Permafrost and glaciation Erosion Human intrusion Redox Other depth related properties