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Synthesis and characterisation of mixed actinide oxalates for the reprocessing of spent nuclear fuels


Key facts

Type of research degree
4 year PhD
Application deadline
Friday 28 April 2023
Project start date
Sunday 1 October 2023
Country eligibility
UK only
Competition funded
Source of funding
Centre for doctoral training
Dr Tariq Mahmud
Additional supervisors
Professor Bruce Hanson
School of Chemical and Process Engineering
Research groups/institutes
Waste Management and Resource Recovery
<h2 class="heading hide-accessible">Summary</h2>

The EPSRC Centre for Doctoral Training (CDT) in Nuclear Energy-GREEN (Growing skills for Reliable Economic Energy from Nuclear) provides a PhD opportunity in the area of reprocessing of spent nuclear fuels. The GREEN CDT is a consortium of five universities of Lancaster, Leeds, Liverpool, Manchester and Sheffield. The CDT has a significant engagement with companies across the nuclear sector. This PhD studentship is based in the School of Chemical and Process Engineering (SCAPE), University of Leeds. In the first year, the CDT research students will undertake week-long modules to develop broad knowledge of the nuclear fuel cycle and undertake training in transferable skills. They will also attend industrial site visits. You will complete your PhD project between the second and fourth years.

<h2 class="heading hide-accessible">Full description</h2>

<p style="margin-top:8px; text-align:justify">The COEX (co-extraction of uranium and plutonium) process for reprocessing of spent nuclear fuels involves coprecipitation of plutonium(III) and uranium(IV) oxalates via the reaction between Pu/U nitrates and oxalic acid. The mixed crystals are filtered, dried, and decomposed in a rotary calciner for conversion to Pu/U dioxides for the fabrication of mixed oxide fuels (MOX). The crystal morphology and size distribution influence the efficiency of these downstream processes and the performance of fuel. The coprecipitation reaction is performed in a continuous vortex reactor agitated with a magnetic stirrer. In precipitation processes, mixing of reactants is of primary importance in determining the local supersaturation, which is crucial for tailoring the crystal attributes.&nbsp;&nbsp;In a previous study, we have investigated the performance of this type of reactor for the precipitation of Ca-oxalate and Ce-oxalate as simulants. The proposed PhD project builds on this study and aims to develop a detailed understanding of how the vortex reactor configuration and operating conditions influence the coprecipitation process and to&nbsp;optimise the reactor performance for the synthesis of mixed actinide oxalates crystals with required properties for an efficient downstream decomposition process. The reactor operation must ensure reproducibility of the product crystals with homogeneously mixed metal ions. Measurements of critical process parameters and crystal properties will provide necessary data for process optimisation and to develop of a coprecipitation process model.&nbsp;</p> <p>Experiments will be carried out in a laboratory-scale vortex reactor in the Nuclear Process Engineering laboratory in SCAPE, University of Leeds. The mixing and residence times in the reactor will be determined using the tracer injection technique involving conductivity measurements. Suitable mixed&nbsp;metal/actinide oxalates&nbsp;will be used&nbsp;as simulants for Pu(III) and U(IV) oxalates for studying the coprecipiation process as functions of reactants feed addition rates and locations, stirrer speed, temperature, reactants concentrations and pH. In situ on-line process analytical techniques (such as IR/UV-vis spectroscopy for solution concentration and video imaging for the evolution of crystal size/shape) will be used for monitoring the precipitation process and off-line techniques (including Malvern Morphologi G3 and SEM/TEM for the crystal imaging and size/shape analyses and powder X-ray diffraction for solid state structure analysis) will be used for characterising product crystals properties.&nbsp;</p> <p><strong><a href="">Centre for Doctoral Training in Nuclear Energy &ndash;&nbsp;GREEN</a></strong></p>

<h2 class="heading">How to apply</h2>

<p>Formal applications for research degree study should be made online through the&nbsp;<a href="">University&#39;s website</a>. Please state clearly in the Planned Course of Study section that you are applying for <em><strong>EPSRC CDT Nuclear Energy-GREEN</strong></em> and in the research information section&nbsp;that the research degree you wish to be considered for is <em><strong>Synthesis and characterisation of mixed actinide oxalates for the reprocessing of spent nuclear fuels</strong></em> as well as&nbsp;<a href="">Dr Tariq Mahmud</a> and <a href="">Professor Bruce Hanson</a> as your proposed supervisors.</p> <p>If English is not your first language, you must provide evidence that you meet the University&#39;s minimum English language requirements (below).</p> <p><em>As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.</em></p> <p class="MsoNoSpacing">Applications will be considered on an ongoing basis. &nbsp;Potential applicants are strongly encouraged to contact the supervisors for an informal discussion before making a formal application. &nbsp;We also advise that you apply at the earliest opportunity as the application and selection process may close early, should we receive a sufficient number of applications or that a suitable candidate is appointed.</p> <p>Please note that you must provide the following documents in support of your application by the closing date of 28 April 2023:</p> <ul> <li>Full Transcripts of all degree study or if in final year of study, full transcripts to date</li> <li>Personal Statement outlining your interest in the project</li> <li>CV</li> <li>Funding information:&nbsp; EPSRC CDT Nuclear Energy &ndash;&nbsp;GREEN</li> </ul>

<h2 class="heading heading--sm">Entry requirements</h2>

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline. The criteria for entry for some research degrees may be higher, for example, several faculties, also require a Masters degree. Applicants are advised to check with the relevant School prior to making an application. Applicants who are uncertain about the requirements for a particular research degree are advised to contact the School or Graduate School prior to making an application.

<h2 class="heading heading--sm">English language requirements</h2>

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.

<h2 class="heading">Funding on offer</h2>

<p class="MsoNoSpacing">A highly competitive EPSRC Centre for Doctoral Training in GREEN studentship, consisting of the award of fees with a maintenance grant (currently &pound;17,668 in academic session 2022/23) for 4&nbsp;years.<br /> <br /> This opportunity is open to UK applicants only.&nbsp; All candidates will be placed into the EPSRC Centre for Doctoral Training in GREEN Studentship Competition and selection is based on academic merit.</p> <p class="MsoNoSpacing">Please refer to the&nbsp;<a href="">UKCISA</a>&nbsp;website for&nbsp;information regarding Fee Status for Non-UK Nationals.</p> <p><em>This project is part of a Cohort wide recruitment process onto the GREEN CDT and funding for individual projects will be determined by selection of the best Candidate(s).</em></p>

<h2 class="heading">Contact details</h2>

<p>For further information about this project, please contact Dr Tariq Mahmud (supervisor): e: <a href=""></a>, t: +44 (0)113 343 2431 or Professor Bruce Hanson (Programme Director): e: <a href=""></a>, t:&nbsp;+44 (0)113 343 0475</p> <p>For further information about your applicationt, please contact Doctoral College Admissions: e:&nbsp;<a href=""></a></p>

<h3 class="heading heading--sm">Linked research areas</h3>