Mechanistic approaches to thermodynamic and kinetic modelling of advanced solvent extraction systems and proliferation resistant flowsheets

Project Description

All commercial nuclear fuel reprocessing plants use the hydrometallurgical PUREX (plutonium uranium extraction) process to chemically separate uranium and plutonium from used nuclear fuel. The separated uranium and plutonium are recycled as new uranium, uranium oxide or mixed oxide fuels whilst the remaining highly radioactive liquid containing, amongst other things, fission products and minor actinides (neptunium, americium and curium) is calcined into glass and stored pending disposal as high level waste.

Internationally, significant research effort is being expended to improve upon the PUREX process, especially with regards to its proliferation resistance (so preventing the use of recovered plutonium in weapons manufacture) and in its management of the highly radiotoxic minor actinides (now to be recycled as fuel materials and so burnt within a reactor rather than being ultimately sent to repository).

The UK National Nuclear Laboratory (NNL) have been developing an Advanced PUREX process that has much in common with the UREX+ and NUEX processes being developed in the US. The NNL’s Advanced PUREX process is centred around the use of acetohydroxamic acid (AHA) or its simpler analogue formohydroxamic acid (FHA) as selective complexants for Pu and Np. This allows for the generation of a high purity bulk uranium product and co-processed U/Pu product, Np also remaining with the latter. The other minor (trivalent) actinides are controlled by similar solvent extraction processes performed on the aqueous raffinate from the Advanced PUREX process.

Much work has already been done on the study of actinide-HA systems of relevance to Advanced PUREX / UREX+. However, key science and technology gaps remain, including how such Pu-AHA/FHA and Np-AHA/FHA complexation reactions can be incorporated into process models..Thus, the fundamental aim of this project is to use a combination of thermodynamic, speciation and kinetic modelling to address these gaps and elucidate, through coupled experiments, the underlying reaction mechanisms, dynamics and structure-activity relationships that control the efficiency of separation of Pu & Np in hydroxamic acid-loaded solvent extraction systems. Ultimately, it is the aim to apply these fundamental models within the process modelling platforms used by industry, thus enabling accurate modelisation of AHA/FHA based flowsheets for the first time.

This is a joint project between the NNL and Lancaster University (LU). Work will involve data-mining and modelling (at LU and on placement at NNL). The RE will be expected to interact closely with non-active proof-of-concept experiments (at LU) and active experiments (at NNL).

Entry requirements

Applicants should have a First or Upper Second Class UK honours degree, or equivalent, in a relevant discipline such chemistry (inc chemical engineering and / or the chemical sciences), materials science or radiochemistry.

Funding Notes

Supported by the Engineering & Physical Sciences Research Council, this studentship is available to start from 1st October 2010. For UK applicants the studentship is fully funded for 4 years, covering fees and a maintenance grant (£14,100 in 2009/10) plus a CASE award of £4000 per year (all tax free, the latter being dependent upon qualifications and experience). EU applicants are eligible for fees only. This studentship is not available to non-UK / non-EU applicants.

Funding Availability: Funding available

Interview Details

Deadline for applications: Tuesday 6th July 2010.

Interview date: Tuesday 20th July 2010.

For further information about this project, contact: Professor Colin Boxall, c.boxall@lancaster.ac.uk, Tel: +44 (0) 1524 593109 or +44 (0) 781 405 5964.

Please include a CV with your enquiry

Application Details

To apply for a PhD at Lancaster University please use the on-line application form.

You should address your background and suitability for this project in your personal statement.

For general information about postgraduate study at Lancaster University please click here.

For specific information on applying for PhD places in the Engineering Department, please contact

Gail Neville, Engineering Department
Email: g.neville@lancaster.ac.uk
Telephone: +44 (0) 1524 592275

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