Available Projects

These are the current projects available with the University of Bristol within the CDT for Nuclear Energy Futures.


Plasticity-induced damage High Temperature Reactors (EDF Energy)

Creep damage is the principal life limiting factor in the life of a thermal plant. In a plant the damage accumulates over decades but to study creep damage root-cause and effects in reasonable timescale, short term experimental testing (creep acceleration) is required. The accelerated creep tests require a detailed understanding of the failure mechanisms to permit extrapolation to lower temperatures and/or stress levels.  A major complication occurs as a result of other damage mechanisms such as time independent plasticity occurring during accelerated test which influence the failure of the specimens and load geometry. Decomposition of creep damage from other damage mechanisms (e.g. plasticity) in an accelerated creep test in the main focus of this project.

The project will employ advanced experimental techniques such as digital image correlation, electron backscattered diffraction and synchrotron X-ray diffraction.  These will be combined with state-of-the-art modelling, including crystal plasticity finite element analysis. The findings from the project will be directly incorporated into design and assessment methods currently being used on High Temperature Nuclear powerplant. Critically, the key results are expected to be included in the integrity assessment procedures the engineers use day to day to evaluate the fitness for service of reactor components. The studentships offer an excellent platform for future career opportunities our alumni have top level jobs at nuclear industry companies.

The work will be carried out in a newly modernised well-equipped high temperature mechanical testing facility at University of Bristol in collaboration with experts at EDF Energy and other researchers in The Solid Mechanics Research Group (SMRG). SMRG is also a regular user of UK major facilities such and Diamond Light Source and ISIS Neutron and Muon Source.

Based in the Department of Mechanical Engineering at University of Bristol (UoB), SMRG focusses on industrially-relevant research in support of low carbon energy sector in the UK.  Since 2008 SMRG has had research partnership with EDF Energy, who are responsible for operating the existing fleet of UK nuclear power plants. The research has recently expanded to close collaboration with UK Atomic Energy Agency (UKAEA) at Culham Centre for Fusion Energy.  This has broadened the facilities and SMRG’s structural integrity activities to include fusion as well as fission. SMRG currently has eight academic staff and approximately 20 students and research staff.

Industrial Supervisors: Dr Marc Chevalier (EDF Nuclear Generation)

Academic Supervisor: Professor David Knowles

Welded joints behaviour in high temperature reactor (EDF Energy)

Welded joints are one of most safety critical locations in a reactor structure. They are often prone to damage after decades of operation and can be considered to be one of the life-limiting factors in the UK’s advanced gas cooled reactors. This is because of the complexities involved in a weld including the residuals stress, varying microstructure and their complicated geometry. The aim of this project is to identify the criticality of the stress concentration created at the interface of a welded joint through advanced experimental techniques such as Digital Image Correlation and synchrotron X-ray diffraction. The experimental work is expected to be complemented by finite element simulations to assess the severity of the creep damage accumulated at the weld interface.  Critically, the key results are expected to be included in the integrity assessment procedures the engineers use day to day to evaluate the fitness for service of reactor components. The studentships offer an excellent platform for future career opportunities our alumni have top level jobs at nuclear industry companies.

The work will be carried out in a newly modernised well-equipped high temperature mechanical testing facility at University of Bristol in collaboration with experts at EDF Energy and other researchers in The Solid Mechanics Research Group (SMRG). SMRG is also a regular user of UK major facilities such and Diamond Light Source and ISIS Neutron and Muon Source.

Based in the Department of Mechanical Engineering at University of Bristol (UoB), SMRG focusses on industrially-relevant research in support of low carbon energy sector in the UK.  Since 2008 SMRG has had research partnership with EDF Energy, who are responsible for operating the existing fleet of UK nuclear power plants. The research has recently expanded to close collaboration with UK Atomic Energy Agency (UKAEA) at Culham Centre for Fusion Energy.  This has broadened the facilities and SMRG’s structural integrity activities to include fusion as well as fission. SMRG currently has eight academic staff and approximately 20 students and research staff.

Industrial Supervisors: Professor David Dean (EDF Nuclear Generation)

Academic Supervisor: Professor Chris Truman

Simulation and experimental validation of Creep – fatigue interaction (UKAEA)

UK is the only country in the world with extensive experience in long term operation of high temperature reactors. Capitalising on the knowledge and expertise, UK is well positioned to lead the international efforts to design and build the high temperature components of a fusion reactor. However, the loading profile of a fusion reactor is different from that of a fission reactor. While a fission reactor experiences only a few hundred major cycles with long dwells in its lifetime, a fusion reactor is expected to see thousands of cycles a year. This will make the damage mechanism from which fusion reactor components suffer, unique.  To design and assess the safety of high temperature component under such brutal loading regime, significant research is required to establish both micromechanical, and their micromechanical consequences of creep and fatigue damage interactions. This project is aimed at simulating this creep fatigue interaction using finite element modelling and validating the model using advanced experimental techniques.

This project is linked to joint work by UK Atomic Energy Authority and University of Bristol on EERA-JPNM (European Energy Research Aliance Joint Programme on Nuclear Materials) on Design Life60+. The work will be carried out in a newly modernised well-equipped high temperature mechanical testing facility at University of Bristol in collaboration with experts at EDF Energy and other researchers in The Solid Mechanics Research Group (SMRG). SMRG is also a regular user of UK major facilities such and Diamond Light Source and ISIS Neutron and Muon Source.

Based in the Department of Mechanical Engineering at University of Bristol (UoB), SMRG focusses on industrially-relevant research in support of low carbon energy sector in the UK.  Since 2008 SMRG has had research partnership with EDF Energy, who are responsible for operating the existing fleet of UK nuclear power plants. The research has recently expanded to close collaboration with UK Atomic Energy Agency (UKAEA) at Culham Centre for Fusion Energy.  This has broadened the facilities and SMRG’s structural integrity activities to include fusion as well as fission. SMRG currently has eight academic staff and approximately 20 students and research staff.

Industrial Supervisors: Dr Mike Gorley (UKAEA)

Academic Supervisor: Dr Mahmoud Mostafavi

High Temperature digital image correlation of small punch test (UKAEA)

Creep damage is the principal life limiting factor in the life of a thermal plant. Materials behaviour in creep regime is evaluated using uniaxial tests. However, the majority of components experience a multi-axial stress state. Stress multi-axiality can have a significant effect on the rate of initiation and growth of creep cavities. Different tests have been proposed to explore the effects of stress multi-axiality on creep deformation and damage in the past of which, small punch tests are gaining more popularity. While inducing an equi-biaxial stress field, presentative of pressurised components, small punch tests concentrate the deformation and damage on the surface of the specimens. This will allow optical techniques such as high temperature digital image correlation technique to be used to interrogate and evaluate damage and deformation during the tests. This project is aimed at designing, optimising, and eventually exploiting optical techniques for creep study of small punch tests. Recently purchased identical equipment at University of Bristol and UK Atomic Energy Authority which allow uninterrupted observation of high temperature small punch tests will be utilised. It is expected that the work is complemented by standard creep tests in order to establish a correlation between the results of the standard tests with those obtained from small punch tests. If significant progress is made, it is expected that the project will expand to exploiting three dimensional techniques such as X-ray tomography combined with digital volume correlation to allow for volumetric interrogation of deformation and damage in small punch tests.

This project is linked to joint work by UK Atomic Energy Authority and University of Bristol on EERA-JPNM (European Energy Research Aliance Joint Programme on Nuclear Materials) on Miniature Test Specimens. The work will be carried out in a newly modernised well-equipped high temperature mechanical testing facility at University of Bristol in collaboration with experts at EDF Energy and other researchers in The Solid Mechanics Research Group (SMRG). SMRG is also a regular user of UK major facilities such and Diamond Light Source and ISIS Neutron and Muon Source.

Based in the Department of Mechanical Engineering at University of Bristol (UoB), SMRG focusses on industrially-relevant research in support of low carbon energy sector in the UK.  Since 2008 SMRG has had research partnership with EDF Energy, who are responsible for operating the existing fleet of UK nuclear power plants. The research has recently expanded to close collaboration with UK Atomic Energy Agency (UKAEA) at Culham Centre for Fusion Energy.  This has broadened the facilities and SMRG’s structural integrity activities to include fusion as well as fission. SMRG currently has eight academic staff and approximately 20 students and research staff.

Industrial Supervisors: Dr Yiqiang Wang (UKAEA)

Academic Supervisor: Dr Harry Coules

An investigation of corrosion and leaching of carbide fuels in a Geological Disposal Facility setting

Uranium carbide (UC) is considered an exotic fuel material which has arisen from the UK’s civil nuclear reactor test programme. This material has served as a prototype high density fuel at sites like Dounreay.

The Nuclear Decommissioning Authority (NDA) has an inventory of irradiated and non-irradiated uranium carbide as part of its legacy waste exotic fuel materials within its estate and therefore carries the liability for its safe management and ultimately its disposal (for which Radioactive Waste Management (RWM), a subsidiary of the NDA are responsible). Uranium carbide is considered a reactive and potentially pyrophoric material with a reactivity comparable to uranium metal.

Geological disposal is internationally recognised as the safest long-term solution for higher activity radioactive wastes and the UK’s exotic spent fuels (such as carbide spent fuel) are intended to be managed in this way. The current PhD project will investigate corrosion and leaching behaviour of irradiated and unirradiated carbide spent fuel under conditions analogous to a Geological Disposal Facility (GDF) both (i) pre-closure and (ii) post-closure.

Most of the UK’s spent fuel inventory is in the form of ceramic uranium dioxide fuels. Oxide provides a stable matrix that is expected to display high chemical stability when contacted by groundwater and, apart from the rapid release of radionuclides at the grain boundaries and in accessible parts of the fuel (the instant release fraction), the rate of release of radionuclides after container failure (the matrix dissolution rate) will be low. Disposal routes for exotic and metallic fuels are yet to be fully determined. It is however expected that carbide and metallic fuels will corrode relatively quickly when accessed by groundwater. This study aim to better underpin the expected behaviour of carbide spent fuel following disposal in a GDF.

Experimental Approach:

Utilising virgin Uranium carbide fuel material provided by the National Nuclear Laboratory (NNL), Springfields laboratory, the current studentship will use cutting edge materials analysis techniques to provide a nano to micro to millimetre scale observation of carbide corrosion behaviour. Techniques will include X-ray tomography (XRT), high-speed atomic force microscopy, secondary ion mass spectrometry, high-resolution electron microscopy and X-ray diffraction. The techniques are all routinely used and available at the IAC in Bristol. To compliment the materials analysis, leaching studies will utilise solution analysis techniques such as ICP-MS and ICP-OES to determine evolving U concentrations in different GDF-analogous groundwater solutions (oxic and anoxic). In addition, the project will also utilise the unique TRLFS instrument available at the University of Surrey which is being developed for aqueous actinides analysis as part of the main TRANSCEND project.

The project will setup a series of enclosed cells experiments, using sealed, water-filled glass housings to hold small uranium carbide ‘stick’ samples in a fixed position. These special cells will permit periodic measurement of the evolving water chemistry using TRLFS and also the corrosion progression using X-ray tomography. These analysis techniques will enable a detailed study of corrosion and leaching behaviour but without disrupting the experimental system. The lower density of the oxide (10.97 g/cc) which forms from corrosion of the carbide (13.66 g/cc) means that rates of oxidation under different conditions (temperature, dissolved O2 and water chemistry) can be determined by measuring the evolving thickness of the oxide using XRT. Feasibility of such experiments has already been proven with several precursor XRT measurements in Bristol.

Isotopic labelling of water saturated corrosion systems will also be used to determine the mechanisms for corrosion of the carbide. Residual gas analysis mass spectrometry will be used in conjunction with such experiments to determine the arising gases under GDF conditions.

The candidate:

It is expected that the prospective candidate will have a 1st or 2.1 class degree in Materials Science, Mechanical Engineering, Physics or a related discipline. Due to likely security clearance requirements there is a strong preference for applications from UK and EU nationals

This PhD project will be funded by Radioactive Waste Management in association with the Nuclear Futures CDT and conducted in conjunction with the EPSRC-funded TRANSCEND project. The student will benefit significantly from access to this consortium, attending and presenting at annual research meetings and workshops.

Industrial Supervisors: Radioactive Waste Management

Academic Supervisor: Professor Tom Scott