Burning petrol and other hydrocarbons from fossil fuels is damaging to the environment and wasteful of resources that could otherwise be used to make substances that improve the quality of life. However, the strength of the carbon-hydrogen bond, coupled with the difficulties associated with selectively accessing a specific site on a particular molecule, means that highly reactive metal compounds are needed to catalyse such processes.A single C-H bond in methane, the simplest and most abundant hydrocarbon, is potentially the most financially important target for selective functionalisation, but the activation of C-H bonds in more complex hydrocarbons is also a highly desirable 'toolbox' component for scientists working in all areas of chemical synthesis. This selectivity will become increasingly more important as our palette of platform chemicals changes from fossil fuel-derived to biomass-derived in the coming years.Organometallic compounds of the lanthanides and actinides first gave a tantalising glimpse of their potential with the selective cleavage of one C-H bond in methane some 25 years ago, but the limitations of the supporting ligands precluded any further functionalisation step. Since then, a variety of C-H bond activation chemistry has been demonstrated at d- and f-block metal centres that has increased our fundamental understanding of this reaction, but not yet provided profitable applications. Recent advances in organometallic f-block chemistry (both in terms of academic breakthroughs, and characterisation methods), and the desire to find C-H activation catalysts not based on the rare and expensive platinum group metals, is now pushing f-block metals back to the forefront of C-H bond activation chemistry.We have made a variety of contributions to organometallic f-block chemistry that challenge traditional views of f-block structure and bonding, such as the isolation of f-block complexes with new polar metal-element bonds (J. Am. Chem. Soc. 2007), and the demonstration of unprecedented reactivity of the U=O oxo groups of the uranyl dication towards C-Si and N-Si bond cleavage (Nature, 2008).The proposed programme of work focuses on the selective activation and functionalisation of hydrocarbon C-H bonds, and builds on our recent successes and proof-of-concept results in functional organolanthanide and actinide chemistry. We have identified three mechanistically distinct types of C-H bond activation, and have combined them into one programme, to offer the highest chance of success. A fellowship offers the ideal opportunity for the PI to manage this intensive and internationally collaborative research programme and deliver new f-block catalysts for hydrocarbon activation.This work contributes to the Energy priority, by providing catalytic, atom-efficient, low-energy chemical routes to convert hydrocarbons from biomass or fossil fuels into high-value chemicals, so benefitting both industry and society.The fundamental understanding that comes from the reactivity and bonding studies of unusual f-block compounds improves our ability to handle nuclear materials and wastes, while the researchers on this project will gain actinide handling skills that are identified as a key shortage in the UK. Finally, the demonstration of important hydrocarbon chemistry by depleted uranium compounds would help to enhance the public image of uranium in our future nuclear age.

As a result of 60 years of using nuclear energy in civil and defence operations, the UK has generated a large legacy of nuclear waste, with a total volume capable of filling Wembley Stadium (450,000m3). The hazards posed to the general public from the radiation arising from this waste make its disposal extremely challenging; any solution must be long-lived as the waste will be radioactive for more than 100,000 years. For this reason, the Governments of several countries, including the UK, propose that the long-term disposal of this waste should be in a deep geological facility, several hundreds of metres below the ground. The formal term for an engineered geological disposal site is a Geological Disposal Facility (GDF). This man-made facility will be used to isolate the waste from future populations by using multiple layers of containment carefully designed to prevent radioactive elements (radionuclides) from entering the underground rock environment and eventually reaching the surface. Arguably, the most important part of the GDF is the nuclear waste itself; the release of radionuclides to the environment is controlled by the interaction of groundwater with the waste - if this material can be shown to be particularly durable in the presence of ground water, the release of radionuclides will be very small and the risk to future populations from the GDF will be low. The focus of my Fellowship is on understanding the release of radionuclides from one particular type of nuclear waste, known as spent fuel, upon contact with groundwater. Many countries are planning to dispose of spent fuel in a GDF (e.g. Sweden, Finland), however the spent fuel in the UK is unique, because it originates from nuclear reactors that only exist in the UK. This is problematic because the potential behaviour of this material when it comes into contact with groundwater is poorly understood; this gives rise to uncertainty in the long-term safety of this material in a GDF. Therefore, the goal of this Fellowship is to develop an understanding of UK spent fuel, of how its structure and chemistry affect the release of radionuclides upon contact with water, and to evaluate its performance compared to other spent fuel types. Because real spent fuel is extremely hazardous, the Fellowship research team will develop an analogue for spent fuel, known as HIP-SIMFUEL, using state-of-the-art material processing technologies. The development of HIP-SIMFUEL, which will resemble spent fuel more closely than any other analogue currently available, represents a significant advancement for scientists working in the field of spent fuel research. Using HIP-SIMFUEL and a suite of advanced, high-resolution microscopy techniques, we will build the first ever atomic-scale understanding of the structure and chemistry of UK spent fuel, and we will develop novel imaging techniques to assess the role of these features in the mechanisms and rate of radionuclide release to groundwater. The results from experiments with HIP-SIMFUEL will be compared with those from real spent fuel particles; my team will examine particles of spent fuel that were discharged to the environment during the Chernobyl accident, which have subsequently been leached by natural groundwater for many years. My Fellowship is particularly timely, given the UK Government's ongoing task of selecting a site for the disposal facility. The research represents a significant step in the understanding of the long-term performance of nuclear waste in the GDF, will enhance predictive models of future GDF behaviour and will help optimise the design of the containment system. Ultimately, this will lead to enhanced safety of the long-term management of nuclear waste in the UK and worldwide, and will increase public confidence of geological disposal concepts.

A thriving nuclear industry is crucial to the UKs energy security and to clean up the legacy of over 50 years of nuclear power. The research performed in the ICO (Imperial Cambridge Open universities, pronounced ECO!) CDT will enable current reactors to be used longer, enable new reactors to be built and operated more safely, support the clean up and decommissioning of the UKs contaminated nuclear sites and place the UK at the forefront of international programmes for future reactors for civil and marine power. It will also provide a highly skilled and trained cohort of nuclear PhDs with a global vision and international outlook entirely appropriate for the UK nuclear industry, academia, regulators and government. Key areas where ICO CDT will significantly improve our current understanding include in civil, structural, mechanical and chemical engineering as well as earth science and materials science. Specifically, in metallurgy we will perform world-leading research into steels in reactor and storage applications, Zr alloy cladding, welding, creep/fatigue and surface treatments for enhanced integrity. Other materials topics to be covered include developing improved and more durable ceramic, glass, glass composite and cement wasteforms; reactor life extension and structural integrity; and corrosion of metallic waste containers during storage and disposal. In engineering we will provide step change understanding of modelling of a number of areas including in: Reactor Physics (radionuclide transport, neutron transport in reactor systems, simulating radiation-fluid-solid interactions in reactors and finite element methods for transient kinetics of severe accident scenarios); Reactor Thermal Hydraulics (assessment of critical heat flux for reactors, buoyancy-driven natural circulation coolant flows for nuclear safety, simulated dynamics and heat transfer characteristics of severe accidents in nuclear reactors); and Materials and Structural Integrity (residual stress prediction, fuel performance, combined crystal plasticity and discrete dislocation modelling of failure in Zr cladding alloys, sensor materials and wasteforms). In earth science and engineering we will extend modelling of severe accidents to enable events arising from accidents such as those at Chernobyl and Fukushima to be predicted; and examine near field (waste and in repository materials) and far field (geology of rocks surrounding the repository) issues including radionuclide sorption and transport of relevance to the UKs geological repository (especially in geomechanics and rock fracture). In addition, we will make key advances in development of next generation fission reactors such as examining flow behaviour of molten salts, new fuel materials, ultra high temperature non-oxide and MAX phase ceramics for fuels and cladding, thoria fuels and materials issues including disposal of wastes from Small Modular Reactors. We will examine areas of symbiosis in research for next generation fission and fusion reactors. A key aspect of the ICO CDT will be the global outlook given to the students and the training in dealing with the media, a key issue in a sensitive topic such as nuclear where a sensible and science-based debate is crucial.