Physicochemical interactions of advanced nuclear fuel and cladding materials

Nuclear power accounts for 20% of the UK energy production making it a critical energy source for the development of society and economy towards Net-Zero. In addition, it is the largest electricity supply of non-greenhouse gas emitting resource, making it key to the UKs greenhouse gas emission reduction targets. However, in 2011, the Fukushima accident highlighted weaknesses of the current UO₂-zircalloy cladding assemblies, whereby during the loss of coolant accident (LOCA) caused fuel temperature to rise to levels where Zr catalysed the production of hydrogen and ultimately lead the explosions of several of the reactor buildings and the fuel core melting down. The poor thermal properties of UO₂ results in a high centreline temperature of the fuel, roughly twice the temperature at the fuel pellet rim. This leads to a shortened time between the loss of coolant and the temperature at which the fuel assembly melts.

New, accident tolerant fuel (ATF) materials, such as uranium silicide (U₃Si₂) and uranium nitride (UN) have enhanced thermal conductivity and aim to reduce the centreline temperatures in the fuel and thus, buy more time in a LOCA scenario for engineers to control the situation. These fuel materials along with other novel cladding materials, such as silicon carbide (SiC) are strong candidates to replace the currently used fuel assemblies in Gen III water called systems. Furthermore, they are also strong candidates for advanced Gen IV nuclear power plant designs, for example, the high temperature gas reactor being pursued by the UK involved particles of fuel materials such as UN coated with graphite and SiC.

However, there is little to no understanding of the chemical interaction between these new fuels and cladding materials in the extreme environments experienced in a nuclear reactor core, which can potentially lead to mechanical failure of the fuel pin and release fission products and radionuclides into the coolant. This project will examine the fuel-cladding interactions of novel fuel materials with current (Zr alloys) and advanced (SiC) cladding materials with/without the presence of fission products under both high temperature and radiation damage environments. The student will be based in the in the National Fuel Centre for Excellence (NFCE) at the University of Manchester which houses equipment for the production of uranium fuel materials within a suite of atmosphere‐controlled glove‐boxes.

This PhD project is part of a wider project on ‘New Fuel Assemblies for Advanced Nuclear’ in collaboration with the University of Oxford, Bangor University, MIT and the National Nuclear Laboratory.

Information about the Nuclear Engineering PhD programme, including entry requirements, can be found at https://www.manchester.ac.uk/study/postgraduate-research/programmes/list/03112/phd-nuclear-engineering/. Applicants should have a background in Materials Science or a related Engineering or physical science subject. 

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