Advanced Waste Management Strategies for Technetium and Iodine in the Nuclear Fuel Cycle

Lead Research Organisation: University of Sheffield
Department Name: Materials Science and Engineering

Abstract

An emerging energy trilemma of energy security, sustainability and affordability, is expected shape the geopolitical and economic landscape of the current century. To address this trilemma, a global expansion of civil nuclear power is underway, providing a reliable source of low carbon base-load electricity, supplied at predictable cost. Sustainable and efficient generation of nuclear energy requires the recycle of nuclear fuel, since only 3% of the material is utilised in common reactor designs. This can only be achieve by developing new materials and processes to enable robust, efficient and safe management of the arising radioactive wastes, which is key, to underpinning public acceptance and reliable cost analysis of civil nuclear power.
Management of technetium and iodine is of particular concern in the recycle of nuclear fuel, since their long half life, high production rate, solubility and bio-accumulation, demands disposition in a robust wasteform, and isolation from the bio-sphere, in a deep geological disposal facility for a ca. 1 million years. Historically, management of Tc and I radionuclides has proven extremely difficult, due to their volatile nature and aqueous solubility, resulting in considerable environmental clean up challenges at Hanford (USA) and Sellafield (UK).
This project will address the management of technetium and iodine in radioactive wastes from nuclear fuel cycles, innovating and developing new materials and processes to safely contain these radionuclides for geological timescales. This challenge is a common need in the civil nuclear power strategies of the UK and Republic of Korea and, therefore, the research will be developed in an integrated and collaborative project, engaging leading researchers from the UK and ROK, each bringing specialist knowledge, capability and skills.

Planned Impact

We identified four groups of beneficiaries who will gain from the research:
1. Public and private sector organisations engaged in fuel cycle operation, will benefit directly from the knowledge and understanding generated by the research, which will assist in reducing the overall cost and hazard of radioactive waste management in future and legacy programmes.
2. The public will benefit from reduced future cost of civil nuclear energy generation and improved environmental outcomes as a result of more robust and holistic radioactive waste management strategies.
3. Policy makers will benefit from improved scientific underpinning of integrated fuel recycle and waste management strategies, which will assist in reducing uncertainties, leading to more accurate economic assessments.
4. The academic community will benefit from a new capability for materials chemistry utilising 99Tc and the provision of

Publications

10 25 50
 
Description This project focused primarily on the design, synthesis and characterisation of ceramic wasteforms for technetium and radioiodine in advanced nuclear fuel cycles, as part of a bilateral collaboration between the UK and Republic of Korea. The project is still in progress, but already substantial progress has been made toward achieving objectives. The project has been supported by two secondments from Republic of Korea in 2015-17, with a third planned for 2017-18.
A systematic study of apatite related compounds, as candidate ceramic wasteforms for the immobilisation and disposal of iodine-129, was completed in the first year of investigation. A key finding was to demonstrate that the solid solution of AgI in these materials is negligible, in contrast to previous literature studies (RSC Advances, 7 (2017) 49004). This is of fundamental importance for industrial application, because radioiodine is typically captured as AgI in flowsheets of advanced fuel cycles, suggesting that such apatite phases may not be as readily exploitable as previously considered. A peer reviewed publication to communicate these research outcomes is currently in progress.
A further significant advance, achieved through secondment of a PhD / PDRA researcher to Sheffield, concerns the development of glass -ceramic materials for the immobilisation of lanthanide and transuranic elements produced from pyro-processing of nuclear fuels. A family of novel vitusite glass-ceramics was designed and characterised, in which the trivalent lanthanide or transuranic elements(M) are targeted for incorporation within the crystalline vitusite - Na3M(PO4)2 phase. A key outcome was an understanding of the crystallisation mechanisms in these materials, required to underpin any future industrial application, as determined by X-ray absorption spectroscopy, which provided evidence for nascent vitusite nuclei within the parent glass phase; see Kim et al., Ceramics International, 43 (2017) 4687-4691.
In parallel, we have developed a unique capability at The University of Sheffield, in the UK academic sector, for handling of weighable quantities of technetium. We have installed and commissioned a negative pressure glove box and developed safe systems of work, which is now in routine operation. An inventory of technetium-99 was received and purified to produce the feedstock for synthesis and characterisation of new Tc(IV) oxides. An early result from this part of the research project was the discovery of a novel and convenient reaction for the conversion of NH4TcO4 into other pertechnetate substrates for synthetic inorganic chemistry. We have subsequently developed this line of research to succcessfully synthesise a range of Tc(IV) oxides of both fundamental interest and potrntial application as ceramic hosts for the immobilisation of Tc-99.
Exploitation Route When matured, research could be taken up by national laboratories and government advisory bodies in designing and implementing flow sheets for immobilisation of higher activity wastes in future advanced fuel cycles.
Sectors Energy,Environment

 
Description This research, as part of a wider portfolio, part sponsored by UKRI, has further developed our understanding of how advanced waste treatment technologies can radically change the risk posed by the inventory of radioactive waste consigned to geological disposal, by eliminating waste reactivity, achieving effective immobilisation of long lived radionuclides, with substantial reduction in waste volume. This evidence was provided to the House of Commons Business, Energy and Industrial Strategy Committee on the Draft National Policy statement for Geological Disposal Infrastructure. The evidence was cited as the key basis for Recommendation 5 in the Committee report, "We recommend that the Government clarifies in the NPS the level of uncertainty regarding the inventory and explains to prospective host communities how this will affect their right to reject the GDI at any point during the siting process" - as set out at paragraph 34 in the body of the report.
First Year Of Impact 2018
Sector Energy,Environment,Government, Democracy and Justice,Manufacturing, including Industrial Biotechology
Impact Types Societal,Economic,Policy & public services

 
Description Impact on Draft National Policy Statement for Geological Disposal Infrastructure
Geographic Reach National 
Policy Influence Type Gave evidence to a government review
Impact Written evidence to the House of Commons Business, Energy and Industrial Strategy Committee on the Draft National Policy statement for Geological Disposal Infrastructure, was cited as the key basis for Recommendation 5 "We recommend that the Government clarifies in the NPS the level of uncertainty regarding the inventory and explains to prospective host communities how this will affect their right to reject the GDI at any point during the siting process" - as set out at paragraph 34 in the body of the report.
URL https://publications.parliament.uk/pa/cm201719/cmselect/cmbeis/1092/1092.pdf
 
Description NIRAB II membership
Geographic Reach National 
Policy Influence Type Participation in a advisory committee
 
Description Written and oral evidence submitted to EPSRC Independent Review of Nuclear Fission and Fusion
Geographic Reach National 
Policy Influence Type Participation in a national consultation
 
Description A new precision cutting saw for radiological materials science
Amount £10,990 (GBP)
Organisation University of Sheffield 
Sector Academic/University
Country United Kingdom
Start 04/2016 
End 03/2017
 
Description DECC - MIDAS capital grant
Amount £800,000 (GBP)
Organisation Department of Energy and Climate Change 
Sector Public
Country United Kingdom
Start 04/2015 
End 03/2016
 
Description ERDF: Royce Translational Centre
Amount £4,005,654 (GBP)
Organisation European Commission 
Department European Regional Development Fund (ERDF)
Sector Public
Country European Union (EU)
Start 02/2018 
End 03/2019
 
Description MIDAS Collaboratory
Amount £800,000 (GBP)
Organisation Department of Energy and Climate Change 
Sector Public
Country United Kingdom
Start 05/2015 
End 03/2016
 
Description Sir Henry Royce Institute - Sheffield Build
Amount £8,770,885 (GBP)
Funding ID EP/P025285/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 03/2016 
End 03/2019
 
Description Sir Henry Royce Institute -Sheffield Equipment
Amount £15,229,114 (GBP)
Funding ID EP/P02470X/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 03/2016 
End 03/2021
 
Description Thermal Treatment of Spent Ion Exchange Resins
Amount £25,010 (GBP)
Funding ID Award value is confidential 
Organisation Ministry of Defence (MOD) 
Sector Public
Country United Kingdom
Start 11/2018 
End 03/2020
 
Description UoS & Suppliers - MIDAS equipment match
Amount £335,000 (GBP)
Organisation University of Sheffield 
Sector Academic/University
Country United Kingdom
Start 04/2015 
End 03/2016
 
Description Collaboration with ESRF XMAS and DUBBLE beamlines 
Organisation European Synchrotron Radiation Facility
Country European Union (EU) 
Sector Academic/University 
PI Contribution Extended application focus of beamline techniques to XAS data acquistion in the hard X-ray regime.
Collaborator Contribution Beamline optimisation to acquire XAS data from glass and ceramic materials in support of plutonium disposition.
Impact See publications section.
Start Year 2016
 
Description DELTA (Dortmunder ELekTronenspeicherring-Anlage) 
Organisation Technical University of Dortmund
Department Dortmund Electron Storage Ring System (DELTA)
Country Germany 
Sector Academic/University 
PI Contribution Development of beamline XAS applications to low concentration detection in disordered systems and expansion of international user programme.
Collaborator Contribution Acquisition of XAS data in hard X-ray regime.
Impact See publications section.
Start Year 2016
 
Description NSLS-II collaboration exploitation and development of X-ray Emission Spectroscopy 
Organisation Brookhaven National Laboratory
Department National Synchrotron Light Source
Country United States 
Sector Public 
PI Contribution This collaboration has developed valence-to-core X-ray emission spectroscopy of the transition metals with the first reported application to niobium. The valence to core region of the XES provides a fingerprint for ligand co-ordination species and is thus a particularly powerful non-contact technique for application to radiological materials. Our team prepared high quality XES specimens of air sensitive reference compounds for investigation by XES and XAS techniques at the Advanced Photon Source and collaborated on data analysis. The techniques developed in this collaboration are a forerunner for application to technetium, which is considerably more challenging given its high specific activity.
Collaborator Contribution Our partners secured beamtime at the Advanced Photon Source and developed bespoke data reduction tools for extraction of the XES and valence to core region, utilising a novel detector system, and also contributed Density Functional Theory calculations to provide theoretical underpinning to data interpretation.
Impact The research resulted in a peer reviewed publication, as a collaboration across the domains of materials science and physics, published as Ravel et al., Phys. Rev. B., 97, (2018), 125139.
Start Year 2017
 
Description POSTECH 
Organisation Pohang University of Science and Technology
Country Korea, Republic of 
Sector Academic/University 
PI Contribution To date, our group has provided facilities and experience to undertake hot isostatic pressing of ceramic materials for immobilisation of radioactive wastes, and characterisation of the resulting materials; this capability is not available in the Republic of Korea. We have also provided training in the application of the Rietveld method for quantitative phase analysis to be applied within research activities at the home institute.
Collaborator Contribution The collaborating research group have provided a skilled PhD student to assist with collaborative research activities in Sheffield on a two month secondment and are planning to second a research fellow for 12 months in 2016.
Impact Incoming secondment of PhD student July - August 2015. Incoming secondment of research fellow planned for March 2016 - March 2017.
Start Year 2014
 
Description POSTECH University 
Organisation Pohang University of Science and Technology
Country Korea, Republic of 
Sector Academic/University 
PI Contribution Pohang University of Science and Technology (POSTEC) are the collaborating partners on our joint UK / ROK project. Our contribution to the joint research programme is the development of ceramic wasteforms for the immobilisation of key radionuclides arising from advanced nuclear fuel reprocessing (I, Tc, Cs, lanthanides and actinides). We have developed a new capability for Tc materials chemistry in the UK and a unique radiological hot isostatic pressing capability to support the joint research. We have hosted several secondments from POSTEC to carry out joint research and train collaborators in advanced materials characterisation techniques (e.g. Quantiative Phase Analysis from X-ray difffraction data, using the Rietveld method).
Collaborator Contribution Pohang University of Science and Technology (POSTEC) are the collaborating partners on our joint UK / ROK project. They have developed complementary development of glass wasteforms for the immobilisation of key radionuclides arising from advanced nuclear fuel reprocessing (I, Tc, Cs, lanthanides and actinides). In particular, POSTEC counterparts have developed a suite of aluminoborate glasses which show high solubility for lanthanide oxides (Ln2O3), which were transferred to our laboratory for investigation of dissolution behaviour.
Impact Several joint research publications have arisen from this research as detailed elsewhere in this submission, further joint publications are being developed.
Start Year 2015
 
Description All Party Parliamentary Group on Nuclear Energy, Palace of Westminster, London, 25 November 2015. 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Invited presentation at All Party Parliamentary Group on Nuclear Energy, Palace of Westminster, London, 25 November 2015. Attended by approximately a dozen parliamentarians and other policy makers, including Energy Minister Angela Leadsom MP. Presentation sparked questions and discussion afterwards.
Year(s) Of Engagement Activity 2015
 
Description IAEA Summer School on Radiation Effects on Radioactive Wasteforms 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Organised Joint ICTP-IAEA Workshop on Radiation Effects in Nuclear Waste Forms and their Consequences for Storage and Disposal, 12-16 September 2016, with engagement of over 30 international researchers.
Year(s) Of Engagement Activity 2017
URL http://indico.ictp.it/event/7633/
 
Description Interview with BBC Radio Cumbria 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Media (as a channel to the public)
Results and Impact Prof. Neil Hyatt was interviewed live on BBC Radio Cumbria, discussing the end of nuclear fuel reprocessing operations at THORP and Sellafield decommissioning challenges.
Year(s) Of Engagement Activity 2019
 
Description Interview with Daily Mail newspaper: GDF siting 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Media (as a channel to the public)
Results and Impact Interview with Daily Mail newspaper on launch of siting process for UK Geological Disposal Facility for radioactive waste.
Year(s) Of Engagement Activity 2018
 
Description MRS Scientific Basis for Nuclear Waste Management XL 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Organised flagship 40th anniversary MRS symposium on scientific basis for nuclear waste management, showcasing research in multiple EPSRC sponsored projects.
Year(s) Of Engagement Activity 2017
 
Description Media and public engagement workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact Delivered a media and public engagement skills summer school for postgraduate and postdoctoral researchers in DISTINCTIVE consortium, which was open to attendance to EPSRC sponsored researchers in nuclear energy.
Year(s) Of Engagement Activity 2016
 
Description Organised: MRS Scientific Basis for Nuclear Waste Management Symposium, 2018 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Organised the MRS Scientific Basis for Nuclear Waste Management Symposium, 2018, which attracted more than 100 experts from around the world for a 4 day symposium on state of the art research outcomes in the field.
Year(s) Of Engagement Activity 2018
 
Description Participation in International Glass Working Group 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Participation in International Glass Working Group - dissemination of research outcomes from multiple EPSRC sponsored projects with the aim of developing a state of the art unified model for glass corrosion, relevant to radioactive waste disposal; participation in expert group designing collaborative international experiments using International Standard Glass.
Year(s) Of Engagement Activity 2017
 
Description SMEA Lecture: Putting the Mission into UK Nuclear Decommissioning 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact New research collaborations identified with attending industrial companies.
Year(s) Of Engagement Activity 2016
 
Description Sheffield scientists pioneer new method for managing radioactive waste 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Television interview as part of World Science day, discussing radioactive waste management research associated with EPSRC sponsored projects.
Year(s) Of Engagement Activity 2017
URL https://vimeo.com/191056195