Projects at Liverpool

These projects are run by Liverpool University. Application information can be found in their how to apply section. Please contact the relevant person below before applying. Click on the titles below to see contact details and more information.

  • Crystallography and thermophysical properties of fission products with coherent domains

    Nuclear fission by its very nature induces change, i.e. transmutation of elements, how a structure accommodates this change is vital to the long-term stability of nuclear fuel. Current nuclear fuel is based on UO2, adopting the cubic fluorite structure, many fission products are soluble within this structure, and can give rise to new phases being formed. These new phases will impact fuel performance, through modification of thermophysical properties, thus potentially reducing the ability of the fuel to be used within the core longer term. The project examines the impact arising from the formation of phases which form as precipitates in the fuel, with a structure formed from ‘non-equilibrium’ synthesis.

    The formation of fission products within fuel, dramatically impacts both the thermophysical and structural response coupling in many cases with the induced radiation damage. For example, not only will fuel
    experience change in microstructure through formation of gas bubbles, but such change induces a reduction in thermal conductivity, which leads to heat being retained within the fuel. Fission product formation within the fuel can either be soluble, or insoluble, with each having differing impact on behaviour. For many fission products there is a miscibility gap in solubility. For example, in the systems U-Ln-O, the miscibility gap gives rise to the formation of new phases, forming coherent domains within the broader matrix. Domain behaviour, and formation is not fully understood and is ripe for further examination.

     

    Contact: Prof Karl Whittle 

  • Role of digital twin concept in decision-making in the nuclear industry

    Digital twins are computational representations of individual physical systems that can be used to model the response of the physical system and inform decisions that have serious consequences. Digital twins have been pioneered in the aerospace industry for scenario analysis; however the nuclear industry has been slow to adopt the approach which offers time and cost reductions combined with safer more reliable operation. The successful implementation of digital twins requires a wide range of stakeholders to have confidence in the outcomes of simulations, i.e. the models and their results must have credibility. While there are established procedures used by modellers for validating computational models, there are no recognised approaches for constructing credibility in the eyes of stakeholders who are not modellers. The aim of this project will be to increase the admissibility of computer simulations to support engineering decision-makers in the civil nuclear industry. The research will include consideration of the place of the digital twin concept within a classification framework based on the degree to which they are principled and testable. This is expect to inform the development of an understanding of the role of confidence and credibility in the relationship between modellers and stakeholders, which in turn will underpin research to establish a methodology for translating modeller confidence into decision-maker credibility. The methodology is likely to include both probabilistic metrics and forms of language that communicate an evidence-based message about model reliability. The methodology will be tested and demonstrated using case studies developed in collaboration with industry.

    Establishing stakeholder confidence is key to maximising the value of computer simulations when applied in the civil nuclear industry. The digital twin concept is used in other industries as a vehicle for improving confidence by enhancing the accessibility and fidelity of the simulation throughout the engineering plant/product lifecycle. This project will assess how the benefits of the digital twin approach can be potentially realised in a civil nuclear context. The project centres on the relationship between the modeller and decision-making stakeholder and how confidence can be established and translated between the two. The role of the digital twin will be considered both as a resource for industrial stakeholders and also as a mechanism to promote public confidence. A series of case studies will be developed to illustrate the insights gained.

     

    Contact: Prof Eann Patterson

     

  • Understanding the mobility behaviour of radionuclides in plasma vitrification of ILW surrogate

    The aim of this project is to get a better understanding and controlling of thermal plasma vitrification process for the treatment of ILW surrogate to bridge the gap between key science and technology. Particular emphasis will be placed on the investigation of the effect of different operating parameters and the roles of plasma generated species on the mobility and transition behaviour of radionuclides (e.g. Cs) during the plasma vitrification of ILW surrogate by optical diagnostics, gas analysis and a wide range of material characterisation techniques (e.g.XRD, XRF, ICP, SEM, leaching test, etc). A novel approach - artificial neural network-genetic algorithm (ANNGA) model will be developed to incorporate experimental data for rapid optimisation of the plasma vitrification process, generating valuable information (e.g. minimise volatile of radionuclides) for process control. This multidisciplinary project will provide a unique chance to gain a more in-depth insight into the mobility of radionuclides and to better understanding of the plasma vitrification process.

     

    Contact: Dr Xin Tu

  • Improved Nuclear Reactor Simulation for the Nuclear Renaissance

    Updating the currently available nuclear reactor modelling and simulation programs is one of the key issues for a successful nuclear renaissance in the UK. The work will create an innovative contribution to the development steps for the UK national program in Digital Nuclear Reactor Design. It will be performed in close co-operation with specialists at the University of Liverpool, Virtual Engineering Centre and industrial partners to assure good guidance and understanding of the industrial demand for improved software solutions. The work will be performed at the inter-connection between modern software development and nuclear reactor technologies with access to advanced high performance computing and virtual engineering technologies.

    Details:

    For the safe and economic operation of the fleet of available and planned nuclear power reactors in the UK the computer codes for the fuel cycle management as well as the determination of important safety parameters play an important role. The safe and reliable operation of LWRs requires a detailed knowledge of safety parameters (spatial power distribution, the control rod worth, pin burnup etc). Nowadays, the neutronics calculations are typically performed at fuel assembly level using the diffusion approximation and assembly-homogenized material parameters. However, for the determination of the safety limits, which are based on local pin parameters, the knowledge of the power and temperature distribution on pin level is essential. This is achieved in current codes by an off-line pin power reconstruction, which is not ideal since feedback effects cannot be considered in this case.

    The methodologies for accurate prediction of the local safety parameters can be combined in a multi-scale and multi-methodological approach. This approach combines a transport solver using the real fuel assembly geometry reproduced on unstructured mesh with the boundary conditions extracted from the 3D full core nodal solution. The key aims of the PhD will be the coupling of the advanced transport solver into a nodal code respecting the requests of a licensing grade software tool. For this purpose a strategy for the cross section preparation for the resolved region handled with the transport code has to be developed. A major challenge is the development of a 2-dimensional interpolation scheme for an improved transfer of the boundary conditions from the nodal code to the transport code. The developed coupled code has to be verified and validated.

    The outcome will be part of a licensing grade software tool with advanced capabilities for coupled calculation of localized pin-wise safety parameters for the nuclear industry. The positive economic effect can be expected due to the reduction of modelling uncertainties following the best estimate strategy in nuclear engineering.

    Contact: Prof Bruno Merk

     

     

     

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