###Thermal and chemical effects on the long- and short-term hydro-mechanical properties of engineered barrier systems in geological disposal facilities
Project ID: 2228bd1189 (You will need this ID for your application)
Research Theme: Energy and Decarbonisation
UCL Lead department: Earth Sciences
Lead Supervisor: Thomas Mitchell
Project Summary:
Currently, significant efforts are being made in industry and academia to explore locations for storing radioactive waste in the subsurface, and ensuring that they remain safely isolated for tens of thousands of years. Manufactured compacted bentonite clays are planned to be used as part of engineered barrier systems in geological disposal facilities (GDF), and are used as a buffer between nuclear waste canisters and the hosting rock formation deep underground. Once the clays hydrate, they swell sealing the canisters tightly in an ultra-low permeability barrier with excellent radionuclide retention. Our previously funded EPSRC research has demonstrated that these favourable properties are likely retained, even at the sub-zero conditions and extreme changes in salinity that might occur during climate variations over many thousands of years (e.g. permafrost during future ice ages). However, strong temperature gradients existing between the waste canisters (several hundreds of degrees) and the cooler surrounding host rock, which may potentially induce thermo hydro-mechanical gradients and potential for inducing leaks.
This project will collaborate with industry (Radioactive Waste Management) and the British Geological Survey. We will use state-of-the-art custom designed and built equipment to test the effects of such gradients, temperature cycling and fluid chemistry on both manufactured compacted bentonite, and a variety of potential host rocks (e.g. sedimentary rocks, granite), in order to test the long term safety of such barriers in a variety of geological settings. We will also look at similar effects on sand/bentonite mixes which are planned to be used as backfill in the larger tunnels of waste repositories.
We are looking for excellent, self-motivated candidates with interest in a cross-disciplinary research project in geological sciences and engineering, and have interest in collaborating with industry.