This project explores one of the most consequential and least fully resolved challenges
in nuclear fuel science: how fission gases and solid fission products interact under
irradiation to shape the performance, safety, and lifetime of nuclear fuel.

Inside a reactor, uranium dioxide fuel is constantly transformed. Fission events generate gases such as xenon and krypton, which migrate through a defect-rich lattice, cluster into bubbles, and interact with evolving microstructures. These bubbles are not passive features. They degrade thermal conductivity, elevate fuel temperatures, drive swelling, and increase mechanical stress on the cladding. Under accident conditions, they can rapidly release stored gas, contributing to sudden pressurisation and potential fuel failure. Despite their importance, current predictive models often treat fission gas behaviour in isolation, overlooking the coupled dynamics between gases, irradiation defects, and other fission products. This simplification limits predictive accuracy and introduces uncertainty in fuel performance simulations, particularly at high burnup and under transient conditions. 

This project develops a cutting-edge multiscale modelling framework to overcome these limitations. It combines Density Functional Theory (DFT) to uncover atomic-scale interaction mechanisms, Kinetic Monte Carlo methods to capture long-timescale defect evolution, and Molecular Dynamics simulations to resolve mesoscale bubble formation and growth. These methods are unified within a scale-bridging framework designed to integrate directly with fuel performance codes. 

A central goal is to quantify and reduce uncertainty in nuclear fuel behaviour by explicitly modelling coupled gas, defect, fission- product interactions. This will lead to more reliable, physics-based predictions of fuel performance under both normal and
extreme operating conditions. 

Aligned with the PANDA DFA programme, the project contributes to advancing high-fidelity, data-informed modelling approaches for complex nuclear systems. It supports the development of robust digital tools for safety-critical applications, with relevance to both civil nuclear energy and defence contexts. 

By combining fundamental physics with advanced computational modelling, this project aims to deliver a step change in our understanding of fission gas behaviour and strengthen the predictive foundations of next-generation nuclear fuel modelling.

Eligibility 

About PANDA 

This studentship is part of the PANDA (Programme for Accelerating Nuclear Development and Applications) Nuclear Doctoral Focal Award. PANDA is a consortium of researchers led by Bangor University and delivered with the universities of Birmingham, Bristol, Cambridge, Derby and Manchester, Imperial College London alongside UK National Nuclear Laboratory. PANDA will train up to 100 doctoral researchers to help meet the UK’s future nuclear, clean energy and defence needs. It is funded by UKRI, the Ministry of Defence and the Department of Energy Security and Net Zero. 

Alongside your research activities you will undertake a rich programme of events including a training programme that includes Nuclear Science and Engineering; Methods for Innovation and the PANDA Professionalism Programme. Due to our close links with industry, there will be opportunities for extended placements with industrial partners, allowing a deeper understanding of what it is like to be a nuclear professional during your studies. 

This studentship covers full tuition fees at the home student rate and an enhanced tax-free stipend of £26,000. The studentship also comes with access to additional funding in the form of a research training support grant which is available to fund research activities including training events, conference attendance, and placements. Students are also supported by the UKRI family leave and pastoral provisions that apply to UKRI-funded studentships, including maternity, paternity, adoption and neonatal care leave. A PANDA hardship fund is also available.