MBase: The Molecular Basis of Advanced Nuclear Fuel Separations

Lead Research Organisation: University of Manchester
Department Name: Chemistry

Abstract

Over 95% of used nuclear fuel is uranium and plutonium, which can be recovered and reused. However, because used fuel is intensely radioactive, this requires very complex processes. These processes can also be adapted to the separation of high hazard materials from the residual radioactive wastes, to simplify radioactive waste management. However, industrial reprocessing of used fuel primarily relies on a 50 year old solvent extraction process (Purex), which was originally developed for much simpler fuels. As a result, modern fuels can prove difficult to reprocess. We will therefore explore two different approaches to nuclear fuel separation in parallel, one based on the established Purex technology and the other on a much more recent development, ion selective membranes (ISMs). ISMs are porous, chemically reactive membranes which can bind metals from solutions then release them again, depending on conditions, thus allowing highly selective separations.In the solvent extraction system, we will focus on a common problem in solvent extraction, third phase formation, and on separation of a group of long lived, high hazard waste isotopes (the fission product technetium and the minor actinides). With the ISMs, we will first prove their utility in uranium/plutonium separation, then extend these studies to the minor actinides. Throughout, we will work with the elements of interest, rather than analogues or low activity models and in realistic radiation environments. In both strands of the project, we will explore the underlying physical and chemical processes then, building on this understanding, we will develop a series of quantitative models, building from phase behaviour to unit operations and finally to process flowsheet models. We wil use the resulting models to explore different options for fuel reprocessing, based on scenarios defined with our industrial partners.

Planned Impact

Beneficiaries The main direct beneficiaries of knowledge and outputs arising from this research will be: - The National Nuclear Laboratory (NNL), responsible for supporting the UK's strategic nuclear R&D and for preserving and developing specialised high level skills. - Idaho National Laboratory (USA) is the US Department of Energy's lead National Laboratory for fuel cycle R&D, aiming particularly to deliver a step change in the nuclear fuel cycle. - The Nuclear Decommissioning Authority (NDA), which is responsible for all of the UK's civil Licensed Nuclear Sites, and Sellafield Ltd (SL), one of the NDA Site License Companies. Sellafield Ltd is responsible for the UK's only operating Purex separation plants, one for metal fuel and one for LWR oxide fuel, and current plans project continuation of reprocessing until at least 2016. - The Health and Safety Executive Nuclear Directorate (ND), which has the statutory responsibility to regulate all Nuclear Licensed Sites. ND and its predecessor, NII, have long promoted skills development in the nuclear sector, an important aim of the MBase consortium. - The UK National Nuclear Centre of Excellence (NNCE) is being set up in response to a recent policy announcement (The Road to 2010) to enhance the UK's work on and capability in non-proliferation. - Government Departments (DECC and Defra), which are responsible for developing policy for the civil nuclear sector. Engagement Mechanisms Consortium Membership. Both NNL and INL are full partners in the consortium, with Serco Assurance participating in the criticality studies. Annual MBase Conference. All consortium members will meet for an annual conference, where key research results, developments and advances will be communicated across the whole consortium and to a wide range of external stakeholders. Public Communication. We will coordinate our activities in this area with the Nuclear FiRST DTC, led by the CRR in Manchester (PI Livens), which is developing an active programme of public engagement. These includes a series of 'Caf Scientifique' events to engage the public, workshop events, participation in the EPSRC Impact programme, and a programme of Schools visits. Web-based Communication. A website detailing the consortium activities and linking to all consortium members will be set up for access by anyone with an interest in the research and its outputs. This will be interactive, featuring for example, a message board for comment and questions, and will also be used to disseminate background information on the scientific context in which the consortium is working (e.g. proliferation-resistance; partitioning as a waste management option; potential for recycling of future fuels).

Publications

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Chen H (2017) Simulation of Neptunium Extraction in an Advanced PUREX Process-Model Improvement in Solvent Extraction and Ion Exchange

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Hardwick HC (2011) Structural, spectroscopic and redox properties of uranyl complexes with a maleonitrile containing ligand. in Dalton transactions (Cambridge, England : 2003)

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Higginson MA (2015) Synthesis of functionalised BTPhen derivatives - effects on solubility and americium extraction. in Dalton transactions (Cambridge, England : 2003)

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Horne GP (2017) Plutonium and Americium Alpha Radiolysis of Nitric Acid Solutions. in The journal of physical chemistry. B

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Horne GP (2016) Multi-Scale Modeling of the Gamma Radiolysis of Nitrate Solutions. in The journal of physical chemistry. B

 
Description Through new, interdisciplinary, international research collaborations, this project is exploring two approaches to nuclear fuel separation, one based on established solvent extraction technology and the other on innovative ion selective membranes (ISMs). In solvent extraction, we are focusing on third phase formation and minor actinide separation and, in the ISM studies, we are focusing on minor actinide separation. We emphasise the use of authentic elements of interest, rather than simulants or low activity species, and also behaviour in realistic radiation environments. We are generating molecular-scale data to underpin a hierarchy of phase-behaviour, unit operation and finally integrated flowsheet models for both solvent extraction and membrane-based separations, and are using these models to explore different reprocessing scenarios, developed in conjunction with industry partners.
Exploitation Route This research will support maintenance of a UK capability in advanced and future nuclear fuel recycling These findings are being exploited through close collaboration with the National Nuclear Laboratory and underpin strategic plans to support critical UK capabilities, currently being made as a result of the Nuclear R&D Advisory Board, chaired by the Government Chief Scientific Adviser. Subsequently, this work supported development of a BEIS-supported Nuclear Innovation R&D programme in which recycle was specifically prioritised.
Sectors Energy

 
Description All researchers associated with this project have gone on to careers in the nuclear sector, an area of critical skills shortage. The work has informed development of the UK Nuclear R&D Roadmap and the work of the UK Government Nuclear R&D Advisory Board
First Year Of Impact 2013
Sector Energy,Environment,Security and Diplomacy
Impact Types Economic,Policy & public services

 
Description Nuclear Advisory Committees
Geographic Reach National 
Policy Influence Type Participation in a advisory committee
Impact Participation in a number of Government advisory committees, principally- Deputy chair, Committee on Radioactive Waste Management Member, Scientific Advice to Government in Emergencies (SAGE) group Member, Cabinet Office Scientific Advisory Committee on High Impact Threats Member, Scientific Advisory Committee, Government Decontamination Service Member, ad hoc Nuclear R&D Advisory Board Co-Author, Nuclear R&D Roadmap
URL https://www.gov.uk/government/organisations/committee-on-radioactive-waste-management
 
Description EU FP7
Amount € 122,000 (EUR)
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 03/2013 
End 02/2016
 
Description AWE National Nuclear Security 
Organisation Atomic Weapons Establishment
Department National Nuclear Security Programme
Country United Kingdom 
Sector Public 
PI Contribution Review, advice
Collaborator Contribution Advice on applications
Impact See main list of putputs- papers by Higginson et al
 
Description National Nuclear Laboratory 
Organisation National Nuclear Laboratory
Country United Kingdom 
Sector Public 
PI Contribution Experimental work with plutonium and neptunium
Collaborator Contribution Provision of facilities; interpretation and analysis of data
Impact See individual grants
Start Year 2009