In-situ disposal of cementitious wastes at nuclear sites

The reuse of construction and demolition wastes at nuclear sites as a fill material supports the UK waste strategy by avoiding costly and environmental disadvantageous off-site disposal.

The project is focused on understanding the interactions of authentic crushed concrete wastes (CCW) produced at NDA sites and longer-lived radionuclide contaminants. Specifically, we will use batch and flow through column experiments to understand the potential for reactive alkaline phases (e.g. calcium-silicate-hydrate, portlandite) in the waste to enhance radionuclide sorption; and, for carbonation reactions with dissolved and atmospheric CO2 to produce secondary minerals (e.g. calcite), which can readily incorporate and immobilise important radionuclides (e.g. Sr-90; U). We will investigate the fate of radionuclides incorporated in, or transported into a CCW fill, and the impact of leachate from aged and freshly crushed materials on the stability of radionuclides in neighbouring contaminated ground.

The student will develop skills in waste characterisation using methods from geochemistry, environmental mineralogy and radiochemistry, utilising state of the art synchrotron and electron microscopy-based analysis. The work will help determine if in situ disposals can meet strict regulatory standards, and, if other associated benefits such as radionuclide attenuation and CO2 capture can be realised in NDA estate closure plans.