Quintessa assists clients with the appraisal of different options for waste packaging, taking into account a broad range of technical factors, cost and stakeholder input. This is complemented by studies aimed at optimising earlier phases of the waste management lifecycle to minimise factors such as cost, risk, hazard and environmental impact.

Also, Quintessa carries out research aimed at understanding and quantifying the potential failure of waste packages during the operational and post-closure phases. This work analyses and models interactions of the container with the wasteform and external environment to assess the nature and quantify the likelihood of potential failure mechanisms. The potential canister materials that have been assessed includes copper, carbon steel, titanium alloys, nickel alloys and stainless steels.

For example, a model and associated software tool has been developed to predict the corrosion behaviour of stainless steel canisters during storage and the operational period of a geological disposal facility. Also, reactive chemical transport modelling has been used to assess the interaction of steel containers with saturated bentonite buffers, and potential corrosion failure mechanisms of copper canisters linked to buffer erosion have been assessed using coupled modelling.

Assessment models and associated software tools have been developed to quantify potential radionuclide releases from waste packages. For example, the STMAN code models releases from high-level vitrified waste, spent fuel ans low-level cementitios waste packages. Also, radionuclide source term models have been developed for a range of intermediate-level wastes, both with and without encapsulants, including irradiated graphite wastes.

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