Students with different backgrounds are mixed (e.g. science and engineering) to make competing teams of 4-5 students on a nuclear themed topic – Challenge Events – and include visits to industrial partner sites and specialist lectures on topics such as intellectual property and innovation, communication and leadership, career opportunities in nuclear and aspects of nuclear regulation, delivered by professionals within and external to the University.
Inspecting the in-core components deformation using Light Imaging, Detection, And Ranging sensor
Supervisor: Dr M. Mostafavi
Industrial Partner: EDF Energy
Nuclear graphite which in UK’s Advanced Gas-cooled Reactors (AGR) is used as neutron moderator and reflector deforms due to radiocally oxidation and irradiation. To ensure the structural integrity of the core and safe operation of control and fuel rods, it is important to monitor the deformation of the nuclear graphite constantly. The current stylus-type system that measures the deformation of the core is envisaged to be phased out in due course and such, it is desirable to investigate the feasibility of novel techniques to measure the deformation.
In this project, in collaboration with EDF Energy, students will be investigating the applicability of a LiDAR system as a non-contact deformation measuring method.
GIS-mapping of potential sites for nuclear reactors and geological disposal facilities
Supervisor: Dr T. Martin
Industrial Partner: Hydrock
An important skill in the construction and development of a nuclear facility such as a reactor or disposal facility is the impact assessment of potential sites using GIS mapping software.
Students will use the software package ArcGIS to survey regions of the UK to establish potential for reactor sites beyond those already planned, and to also investigate the geographical, environmental and political restrictions to the construction of a geological disposal facility in the UK.
Students will provide a report indicating where their GIS analysis suggests potential facilities could be sited.
When will commercial nuclear fusion be realised?
Supervisor: Dr R. Springell
Industrial Partner: CCFE
Students will provide an in-depth report addressing economic, technical, socio-political factors on a realistic time scale for the implementation of commercial nuclear fusion.
Sellafield Decontamination Challenge
Supervisor: Dr J. Velthius
Industrial Partner: Sellafield
The Sellafield site has a raft of decommissioning challenges. Before we embark upon decommissioning, there is an interim phase called POCO (Post Operational Clean Out). The purpose of this phase is to remove as much radioactivity as possible and de-risk the future decommissioning activities. Key points to consider are Access and Characterisation methods.
The vessels have seen fuel dissolved in nitric acid and can be considered Highly Active. The plant items we are considering are known as Mixer Settlers and have seen many decades of service. Equally, there has been a build-up of solids and solvent degradation products. The challenge is to consider how a mixer settler would be characterised for radiation measurements and radioisotopes to such an extent that we can reasonably consign any separated wastes as Low Level Waste or Intermediate Level Waste without creation of new access points into the cell.
Sizing up the Dragon's Lair
At Sellafield, processes have been developed for the processing of high level wastes, including highly active liquors (HAL), a result of reprocessing irradiated nuclear fuel.
HAL consists of fission products dissolved in highly concentrated nitric acidic and is stored in Highly Active Storage Tanks (HAST) which provide controlled storage conditions including cooling, agitation and monitoring.
At the Sellafield site, HAL has been safely stored for more than 40 years and a vitrification technology has been implemented whereby the liquid waste is converted to a stable, solid state suitable for transport and long term storage. The age of some of the HAL facilities is such that they need to be operationally retired, cleaned out and decommissioned. Before this can be undertaken there is a need to fully characterise the residual state of these tanks. Specific questions to answer are:
Q: What is the distribution of fissile material in the tanks?
Q: Have the tanks maintained structural integrity for containment of HAL?
Q: What is the distribution of radioactivity within the HAST facilities?
Answering these questions represents a significant challenge because the tanks, 3m diameter and 16m long, are housed in pairs inside reinforced concrete cells. The tanks have two ceiling located 40mm standpipes to provide access and the cell has but one ceiling located access pipe 150mm in diameter. An additional challenge is the level of radiation within the cells, which has been measured as >100Sv/hr in the cell just 1m above the tanks. This extreme level of radiation means that most all electronic devices will rapidly damage and fail.
The group challenge is to devise one or more realistic solutions for answering the three questions listed above. Planning and research must consider cost, technology and timescale.
Graphite condition monitoring with Assystem
Four students from the 2017/18 cohort visited the Preston offices of Assystem Energy & Infrastructure Limited as part of their group project on alternative methods of condition monitoring of graphite bricks within the current nuclear fleet. This project was sponsored by EDF Energy.
One of the students, Rachael Matthews, said:
"The trip to Assystem provided valuable insights into current non-contact surface metrology techniques. Learning from Assystem's own research gave us many ideas to take forward within our project.
Seeing the work done in Assystem related to our own project, and the enthusiasm of the people there, gave our team a huge boost and underlined the importance of this very real world problem!"
Individual Research Projects
Projects are overseen by supervisors from Mechanical Engineering/Civil Engineering/Physics/Chemistry/Earth Sciences.
These projects have academic supervision, but will often be accompanied by industrial support and most of the projects will be aligned to important industrial problems. Potential project contributions for the nuclear MSc will come from strategic partners EDF, Sellafield, NNL, Rolls-Royce, RWM and AREVA. At the University of Bristol we have access to a large suite of instrumentation, some of which is dedicated specifically to nuclear materials research. Some of the research instruments are unique in the UK. Students may also have the opportunity to work on the sites of the project partners.
Research projects normally involve an extended investigation into the application of a novel component or technique, and they offer the opportunity for an in-depth study of a specialised subject. Each project is carried out under the supervision of a member of staff. The project contains a research or investigative element which allows a student to demonstrate individual talent and intellectual ability. It attempts to mirror a research and/or development project of the type that may be encountered upon graduation and as such contains elements of project planning. The project report provides an opportunity for the student to demonstrate report structuring and writing skills.
Imaging nuclear fuel debris using ultrasonic arrays
Supervisor: Dr R. Malkin
Industrial Partners: University of Sheffield, Tokyo Institute of Technology, Hitachi Japan
To successfully decommission both Chernobyl and Fukushima nuclear power plants it is of vital importance to understand the physical composition of corium (concrete-uranium). In Japan, the Tokyo Electric Power Company (TEPCO), which is responsible for the decommissioning, has stated many times that knowing the location of the fuel debris/corium is its top priority. Thus far however, no inspection techniques have provided any information about the location and/or composition of the fuel debris.
The project will seek address this by using ultrasonic waves to penetrate sample blocks of concrete (with embedded fuel debris simulant). Traditional ultrasound which can travel inside concrete is generally low frequency which limits the spatial resolution for imaging the internal structure. In the project we will develop an array of ultrasonic transducers (16-32 of them) and use the latest imaging techniques to overcome this limitation. The work will involve both practical experiment, device manufacture and signal processing of the data. Students may also be able to attend a national/ European conference.
The value of life: comparing J-value and VPF with New Sentencing Guidelines
Supervisor: Prof P. Thomas
Industrial Partners: Ashfords LLP
The New Sentencing Guidelines were issued to the legal community in the UK in February 2016 to guide sentencing in court for health and safety offences. The fines now available are calibrated for the size of the organisation found at fault, but are uniformly very much higher than before. Thus a breach that is found to have high or very high culpability can lead to fines of between £6M and £10M for an organisation with a turnover of more than £50M per year and there is scope to increase the fines beyond these figures for organisations who are regarded as 'very large'.
This may be compared with a "value of a prevented fatality", VPF, of £1.8M in 2016. Meanwhile the J-value would predict an average value of life in the UK to be much closer to the figures contained in the New Sentencing Guidelines. True comparisons will, however, require reasonable models for the size of the accident, the extent of culpability, the likelihood of being taken to court and the likelihood of conviction. A further factor that should be taken into account is flawed nature of the process by which the VPF was estimated.
Radiation mapping and Forensic Analysis of Pary’s Mountain
Supervisor: Prof T. Scott and Dr A. Keatley
Industrial Partner: NNL
Parys Mountain – is located south of the town of Amlwch in north east Anglesey, Wales. It is the site of a large copper mine that was extensively exploited in the late 18th century. The spoil material across the site is well recognised to have a radiological contamination, some of which is considered to be naturally derived and some which is considered anthropogenic (derived from nearby Wylfa power station).
The project will provide a combined ground and air survey including photogrammetry, scanning LiDAR and radiometric mapping. Radiation hotspots identified by the surveys will be sampled and collected soil/rock will be analysed in the Bristol (IAC) laboratories using high resolution gamma spectrometry combined with XRF and SEM-EDX analysis to provide elemental identification of the radiation-emitting materials.
Shutdown Control Rod Entry Acceptance Criteria for Reactor Cores Distorted Under Seismic Loading
Supervisor: Anna Rudge / Jim Reed / Mike Healey (EDF Energy)
Industrial Partner: EDF Energy
Control rods are used to shutdown AGR reactor cores. During a seismic event the vertical control rod channels distort. As the graphite cores age, these levels of distortion can increase. It is important that the levels of distortion remain within acceptable limits ensuring a very high reliability for control rod entry in to the vertical channels. At present the acceptance criteria for control rod entry is based on simple 3 point contact at the peak distortions during the seismic event. The purpose of this project is to develop the acceptance criteria including;
1. Distortions which would preclude control rod entry at the end of the seismic event due to permanent distortion of the control rod during the event as it enters the core e.g. the bent control rod no longer fits in to the ‘end of event’ distortion pattern for the channel.
2. Interaction between the control rod and the graphite core – interface loads.
3. Correlate existing rig data to the acceptance criteria and develop an understanding of the critical channel distortion features precluding control rod entry (zig-zags, interface sliding etc).
4. Understand how the dynamic behaviour during the seismic event compares to the rig test data which is performed under static conditions.
5. Define what rig tests could validate the revised criteria and be involved with such rig tests.
6. Develop reliability criteria for different types and severities of channel distortions.
Probabilistic Structural Integrity Assessment for Nuclear Pipework - Leak before Break
Supervisor: Professor D. Knowles/Feras Elgha
Industrial Partner: Atkins
Leak before break arguments made for nuclear pipework are traditionally based on deterministic analyses using conservative assumptions on defect size/growth, crack opening area, leak rate and critical crack size. Such assessments for UK nuclear plant are generally based on the R6 procedure  which does provide separate guidance on leak before break and on undertaking probabilistic methods for determining the critical crack size.
This project aims to develop a calculation method / tool using probabilistic means considering uncertainties in inputs including those within inspection methods to calculate crack growth, leak rate and critical crack sizes. The calculations will consider the sensitivity of key assumptions/inputs such as inspection methods and uncertainties, crack evolution, crack opening area representation and material properties (fracture toughness/tearing, yield). The project will also aim to establish the success/failure criteria using fast fracture, leak before break.
The developments from this project are applicable to support asset integrity management in all industries. Using probabilistic means for structural integrity assessments allow for a better understanding and measure of the key parameters as well as having a direct influence on the probability of failure used in safety case submissions.