GREENCDT Actinide Colloid behaviour in alkaline conditions: Implications for Radioactive Effluent Treatment Processes.

Supervisors

1. Prof. Sam Shaw
2. Prof. Kath Morris
3. Dr Tom Neill

Globally, engineered ‘ponds and silos’ are used for storage of spent nuclear fuels. Decommissioning of legacy fuel ponds and silos is a key priority for the UK, and countries worldwide. Alkaline wastewater effluent from these spent nuclear fuel ponds and silos can contain significant radioactive loadings, and management of the effluents is essential to their safe decommissioning (www.sellafield.com). In the UK, at Sellafield, pond effluents are treated by neutralisation, filtration and ion exchange processes prior to the authorised discharge of the very low level treated effluents to the environment via pipeline to the Irish Sea. Recent studies from our group (Neill et al 2018, 2022 and Foster et al. 2022) using a range of state-of-the-art approaches (e.g. Diamond Light Source http://www.diamond.ac.uk) have highlighted the potential for colloid formation in waste waters from the legacy ponds and silos. Research shows that these nanoparticulate colloids are stable across a range of likely effluent conditions, and are important in controlling the mobility of a range of radionuclides e.g. uranium, plutonium and strontium-90. Understanding the behaviours of these colloids has potential implications for the optimisation of the decommissioning of the legacy pond and silo facilities at Sellafield. Fundamental research into the ponds effluents is required to support the clean-up programme at Sellafield over the next decades, as highlighted in a recent impact report ( see https://www.manchester.ac.uk/research/impact/showcase/improving-radioactive-waste-management-at-sellafield/)

This PhD project will further develop our highly innovative work based on treatment of alkaline effluents. The key aim will be to characterise the nanoparticle chemistry, structure and colloid stability in the presence of key radionuclides, and explore the reaction of the radionuclides with the colloidal particles. This in turn will be used to determine the effect of the colloids on effluent treatment. Overall, the project will provide essential information on radionuclide speciation and fate in these complex systems and the researcher will have the opportunity to work with Sellafield to directly inform the pond decommissioning process, a project of the highest national significance. More generally, the presence of radionuclide colloids in alkaline conditions is relevant in a range of settings including radioactive waste disposal and environmental remediation and many of the skills in this project translate to these areas.

Training:

This PhD studentship is co-funded by Sellafield and the EPSRC GREEN CDT and involves supervision from the National Nuclear Laboratory. This industrially sponsored PhD project will be based in the RADER facility (https://www.nnuf.ac.uk/rader) within the Department of Earth & Environmental Sciences at The University of Manchester. The project will be experimental, and the successful candidate will join a significant ongoing research effort in the nuclear environment and waste area in the group. The project will be based at The University of Manchester and run in close collaboration with Sellafield Ltd. and the National Nuclear Laboratory. Currently, the group has over 20 PhD researchers training across the nuclear environmental area and all of our nuclear PhD graduates gain prompt employment in nuclear related academia / industry / regulatory roles. The researcher will also benefit from the excellent facilities within the RADER Facility and the Williamson Research Centre for Molecular Environmental Science which include facilities for radiochemical, chemical, mineralogical and colloidal characterisation of samples. Students will also have access to advanced facilities available within The University of Manchester (e.g. electron microscopy, X-ray photo electron spectroscopy, mass spectrometry) as well as national and international facilities where we can analyse radioactive samples such as the Diamond Light Source (http://www.diamond.ac.uk). Finally, the students will work closely with industrial supervisors within the National Nuclear Laboratory and Sellafield to ensure their research is focussed on real site challenges and has optimal impact at Sellafield.

Specification:

This project is experimental in scope and the successful candidates should have a strong background in the Chemical / Environmental Sciences (BSc / Masters in Chemistry, Environmental Chemistry, Geochemistry, Geosciences or similar). If you require further details about the project, please contact the supervisors, Prof. Sam Shaw (sam.shaw@manchester.ac.uk) and / or Prof. Katherine Morris (kath.morris@manchester.ac.uk). Applications can be made through The University of Manchester site http://www.manchester.ac.uk/study/postgraduate-research/admissions/