Nuclear energy supplies approximately 20% of the UK’s energy. While this power is greenhouse-gas free, reactor components and waste materials represent long term radiation hazards. To address this hazard the permanent disposal of wastes is planned in a Geological Disposal Facility (GDF).
Project background
GDF’s are designed to contain and prevent the release of radionuclides into the environment. Ensuring that GDF components will safely contain radionuclides during long-term disposal is a priority. As a result, understanding the environmental processes, especially the fate and management of produced gases, that could occur over the GDF’s life span, and the implications of those processes on containment is critically important. The projects focus on gas management from Low Heat Generating Wastes (LHGW). LHGW include intermediate level waste (ILW) arising from the operation and decommissioning of reactors and other nuclear facilities, and a small amount of low level waste (LLW) unsuitable for near surface disposal.
Project 1: Microbial Consumption of GDF Gases and Implications for Long-Term GDF Performance
Gases will be produced during container corrosion and may overpressurize the GDF, but the ultimate fate of GDF gases remains uncertain. This project will investigate the role of microbiological activity in consuming produced gases and its impacts on GDF components to ensure Engineered Barrier System (EBS) performance over the planned lifespan. Experiments will re-create GDF conditions predicted to be dominant over the one million year safety assessment timeframe, assess how microbial processes are consuming gases, and identify by-products and geochemical reactions from gas consumption. An emphasis of the work will be testing how these by-products and geochemical reactions impact the performance of each GDF component. Computer modelling will be used to predict the implications of experimental results for long-term GDF performance.
Project 2: LHGW GDFs in the Circular Economy: Utilising waste rocks as Engineered Barrier System material
The Engineered Barrier System (EBS) is a key component for GDF safety. The EBS slows the flow of water to limit corrosion, protects the structural integrity of the container, and prevents radionuclides from being released into the environment. The EBS is intended to manage gases produced during container corrosion and waste degradation, through providing pore-space to passively control gas release by storage and to limit pressures. This project explores use of waste rocks from quarries, excavated GDF rocks and re-use of other materials (e.g. concrete waste from NDA sites) for the EBS. Their use as an EBS material would lower the environmental footprint and prevent these materials from filling landfills. We will assess whether waste rock/bentonite mixtures meet criteria for EBS usage, including mechanical strength, fluid/gas permeability, microbial activity for gas consumption and the long-term performance of these re-used materials.
Training
A comprehensive training programme will be provided comprising both specialist scientific training and generic transferable and professional skills. The supervisory team has significant expertise in all of the required experimental and numerical/computational techniques for this project. They will be providing training and support for the experimental work as well as programming/numerical-based model development.
Requirements
Minimum entry qualification - an Honours degree at 2:1 or above (or International equivalent) in a relevant science or engineering discipline.
Applications are welcome from students with backgrounds in chemistry, earth and geosciences, civil and environmental engineering, microbiology or other closely related disciplines.
Industry Links
You will have the chance to work closely with leading edge industrial partners. This project is funded through Radioactive Waste Management (RWM) and work will be conducted in close collaboration with both RWM, and the project’s industrial partner Quintessa
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