The conditions in which materials are required to operate are becoming ever more challenging. Operating temperatures and pressures are increasing in all areas of manufacture, energy generation, transport and environmental clean-up. Often the high temperatures are combined with severe chemical environments and exposure to high energy and, in the nuclear industry, to ionising radiation. The production and processing of next-generation materials capable of operating in these conditions will be non-trivial, especially at the scale required in many of these applications. In some cases, totally new compositions, processing and joining strategies will have to be developed. The need for long-term reliability in many components means that defects introduced during processing will need to be kept to an absolute minimum or defect-tolerant systems developed, e.g. via fibre reinforcement. Modelling techniques that link different length and time scales to define the materials chemistry, microstructure and processing strategy are key to speeding up the development of these next-generation materials. Further, they will not function in isolation but as part of a system. It is the behaviour of the latter that is crucial, so that interactions between different materials, the joining processes, the behaviour of the different parts under extreme conditions and how they can be made to work together, must be understood. Our vision is to develop the required understanding of how the processing, microstructures and properties of materials systems operating in extreme environments interact to the point where materials with the required performance can be designed and then manufactured. Aligned with the Materials Genome Initiative in the USA, we will integrate hierarchical and predictive modelling capability in fields where experiments are extremely difficult and expensive. The team have significant experience of working in this area. Composites based on 'exotic' materials such as zirconium diborides and silicon carbide have been developed for use as leading edges for hypersonic vehicles over a 3 year, DSTL funded collaboration between the 3 universities associated with this proposal. World-leading achievements include densifying them in <10 mins using a relatively new technique known as spark plasma sintering (SPS); measuring their thermal and mechanical properties at up to 2000oC; assessing their oxidation performance at extremely high heat fluxes and producing fibre-reinforced systems that can withstand exceptionally high heating rates, e.g. 1000oC s-1, and temperatures of nearly 3000oC for several minutes. The research planned for this Programme Grant is designed to both spin off this knowledge into materials processing for nuclear fusion and fission, aerospace and other applications where radiation, oxidation and erosion resistance at very high temperatures are essential and to gain a deep understanding of the processing-microstructure-property relations of these materials and how they interact with each other by undertaking one of the most thorough assessments ever, allowing new and revolutionary compositions, microstructures and composite systems to be designed, manufactured and tested. A wide range of potential crystal chemistries will be considered to enable identification of operational mechanisms across a range of materials systems and to achieve paradigm changing developments. The Programme Grant would enable us to put in place the expertise required to produce a chain of knowledge from prediction and synthesis through to processing, characterisation and application that will enable the UK to be world leading in materials for harsh environments.

The conditions in which materials are required to operate are becoming ever more challenging. Operating temperatures and pressures are increasing in all areas of manufacture, energy generation, transport and environmental clean-up. Often the high temperatures are combined with severe chemical environments and exposure to high energy and, in the nuclear industry, to ionising radiation. The production and processing of next-generation materials capable of operating in these conditions will be non-trivial, especially at the scale required in many of these applications. In some cases, totally new compositions, processing and joining strategies will have to be developed. The need for long-term reliability in many components means that defects introduced during processing will need to be kept to an absolute minimum or defect-tolerant systems developed, e.g. via fibre reinforcement. Modelling techniques that link different length and time scales to define the materials chemistry, microstructure and processing strategy are key to speeding up the development of these next-generation materials. Further, they will not function in isolation but as part of a system. It is the behaviour of the latter that is crucial, so that interactions between different materials, the joining processes, the behaviour of the different parts under extreme conditions and how they can be made to work together, must be understood. Our vision is to develop the required understanding of how the processing, microstructures and properties of materials systems operating in extreme environments interact to the point where materials with the required performance can be designed and then manufactured. Aligned with the Materials Genome Initiative in the USA, we will integrate hierarchical and predictive modelling capability in fields where experiments are extremely difficult and expensive. The team have significant experience of working in this area. Composites based on 'exotic' materials such as zirconium diborides and silicon carbide have been developed for use as leading edges for hypersonic vehicles over a 3 year, DSTL funded collaboration between the 3 universities associated with this proposal. World-leading achievements include densifying them in <10 mins using a relatively new technique known as spark plasma sintering (SPS); measuring their thermal and mechanical properties at up to 2000oC; assessing their oxidation performance at extremely high heat fluxes and producing fibre-reinforced systems that can withstand exceptionally high heating rates, e.g. 1000oC s-1, and temperatures of nearly 3000oC for several minutes. The research planned for this Programme Grant is designed to both spin off this knowledge into materials processing for nuclear fusion and fission, aerospace and other applications where radiation, oxidation and erosion resistance at very high temperatures are essential and to gain a deep understanding of the processing-microstructure-property relations of these materials and how they interact with each other by undertaking one of the most thorough assessments ever, allowing new and revolutionary compositions, microstructures and composite systems to be designed, manufactured and tested. A wide range of potential crystal chemistries will be considered to enable identification of operational mechanisms across a range of materials systems and to achieve paradigm changing developments. The Programme Grant would enable us to put in place the expertise required to produce a chain of knowledge from prediction and synthesis through to processing, characterisation and application that will enable the UK to be world leading in materials for harsh environments.

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.