Effect of crystallite reorientation on the behaviour of nuclear grade graphite

As part of the UK’s transition to a low carbon economy, the UK Government is committed to delivering new and advanced nuclear power, and has stated its preference for High Temperature Gas Reactors (HTGRs) and Advanced Modular Reactors (AMRs) [1]. HTGRs and numerous AMR designs use graphite in the reactor core, where it not only acts as a neutron moderator/reflector, but as a structural component. The graphite plays a pivotal role in the reactor and can dictate the operational lifetime of a reactor. Thus, it is essential that the designer and operators of HTGRs and AMRs have an understanding of how the graphite and graphite components within the reactor core will behave both during reactor operation and under accident scenarios.

In an HTGR or AMR core, the graphite will be subjected to temporal and spatial variations in fast neutron fluence, temperature, and, in some cases, thermal oxidation. The combination of these loadings leads to changes in the material properties and dimensions of the graphite [2]. A phenomenon of particular interest to reactor designers and operators is irradiation-induced creep, as this has a significant effect on the internally generated stresses in graphite components and can affect other material properties, most importantly the coefficient of thermal expansion (CTE) [3, 4]. There is no accepted mechanism for irradiation creep in graphite and how irradiation creep causes a change in CTE. At present, designers and operators of graphite-moderated reactors are using empirically based relationships to predict this behaviour. This could lead to difficulties when the operating regime of the new HTGR or AMR goes beyond the regime (fluence and temperature) of the available data, which is also based upon a graphite grade that is no longer available. An improved understanding of the mechanisms behind irradiation creep and the change in other material properties, in particular CTE, will aid the interpretation and extrapolation of what data are available, and provide improved confidence in the predicted behaviour of graphite components in HTGRs and AMRs.

The main hypothesis of the project is that the change in the CTE of graphite due to irradiation-induced creep is linked with the reorientation of the graphite crystallites within the bulk structure. The main aim of the project is to measure any reorientation of graphite crystallites due to creep-related processes and relate this to changes in measured CTE.

Eligibility

Applicants should have, or expect to achieve, at least a 2.1 honours degree or a master’s (or international equivalent) in a relevant science or engineering related discipline.

Funding

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For more information, visit our funding page or search our funding database for specific scholarships, studentships and awards you may be eligible for.

Before you apply

We strongly recommend that you contact the supervisor for this project before you apply.

How to apply

Apply online through our website: https://uom.link/pgr-apply-2425

When applying, you’ll need to specify the full name of this project, the name of your supervisor, if you already having funding or if you wish to be considered for available funding through the university, details of your previous study, and names and contact details of two referees.

After you have applied you will be asked to upload the following supporting documents: 

• Final Transcript and certificates of all awarded university level qualifications
• Interim Transcript of any university level qualifications in progress
• CV
• Supporting statement: A one or two page statement outlining your motivation to pursue postgraduate research and why you want to undertake postgraduate research at Manchester, any relevant research or work experience, the key findings of your previous research experience, and techniques and skills you’ve developed. (This is mandatory for all applicants and the application will be put on hold without it).
• Contact details for two referees (please make sure that the contact email you provide is an official university/work email address as we may need to verify the reference)
• English Language certificate (if applicable). If you require an English qualification to study in the UK, you can apply now and send this in at a later date.

If you have any questions about making an application, please contact us via email: SATURN@manchester.ac.uk

Equality, diversity and inclusion is fundamental to the success of The University of Manchester, and is at the heart of all of our activities. We know that diversity strengthens our research community, leading to enhanced research creativity, productivity and quality, and societal and economic impact.

We actively encourage applicants from diverse career paths and backgrounds and from all sections of the community, regardless of age, disability, ethnicity, gender, gender expression, sexual orientation and transgender status.

We also support applications from those returning from a career break or other roles. We consider offering flexible study arrangements (including part-time: 50%, 60% or 80%, depending on the project/funder).