BIogeochemical Gradients and RADionuclide transport. BIGRAD

Lead Research Organisation: University of Manchester
Department Name: Earth Atmospheric and Env Sciences

Abstract

Over 50+ years of nuclear power generation and weapons development, the UK has created large quantities of radioactive wastes. In terms of total volume, the largest fraction (> 90 %) of the higher activity waste is Intermediate Level Waste (ILW). ILW does not produce heat but contains long-lived radioisotopes, and so cannot be disposed of near the Earth's surface. The Government has recently decided that the UK's ILW should be disposed of underground (200 - 1000 m) in a 'Geological Disposal Facility' (GDF). The safety of a GDF depends on slowing the return of radioactivity from the GDF to Earth surface. Understanding the processes which control the movement of radioactivity out of the GDF and to the rock and beyond is therefore critical. The UK's ILW is very diverse and includes discarded nuclear fuel, the metal containers used to hold fuel, as well as sludges and organic debris produced when processing these radioactive materials. The UK has treated many of these radioactive wastes by immobilising them in cement and a substantial fraction of ILW has now been cemented and awaits disposal. Once the wastes have been placed in the GDF, the intention is to backfill the remaining space with cement. No site has been identified for UK wastes as yet, but it is expected that the site will be under the water table and therefore be wet. This means that, after the waste is emplaced, the GDF will rewet as groundwater percolates through the wastes. Over a long time (from hundreds to millions of years) the ILW and its steel containers will degrade, and the cement will react with the groundwater to make it very alkaline. This is a design feature, as very alkaline, 'rusty' conditions are expected to make most radioactive components of the ILW very insoluble. However, this alkaline water will react with the rock around the repository to form a 'chemically disturbed zone' (CDZ). Up until now, no studies have examined the chemical, physical and biological development of this CDZ and how this affects the mobility of radioactive contaminants from the GDF. We have chosen to study four long-lived radionuclides, the fission product technetium as well as uranium, neptunium and plutonium all of which will be present over the long timescales relevant to the CDZ. In this project, we will try and understand how the CDZ will evolve over thousands to millions of years, so we can predict the movement of radioactivity through it, and help assess the safety of the GDF. To do this, we need to study the chemical, physical and biological changes which occur as the CDZ develops, and the way in which these different factors interact with each other. We will use experiments to understand these processes and, based on these, we will develop computer models to predict what will happen in the future. We have divided our work programme into three parts: 1 Geosphere Evolution, where we will examine rock and mineral interactions, and how water flow within the rock is affected by chemical and microbiological changes caused by the water from the GDF; 2 Radionuclide Form, Reaction and Transport, where we will examine the chemical form and solubility of radionuclides, their interactions with microorganisms, and with rock surfaces, and the potential for microscopic particles to carry radioactivity; 3 Synthesis and Application, where we will bring all the experimental results together and design, develop and test our computer model to examine radionuclide transport in the CDZ. To ensure we link the different parts of the project effectively, we have identified two 'cross cutting themes' (CCTs) - (i) biogeochemical processes in the CDZ; and (ii) predictive modelling of the CDZ, which will tie all the different pieces of work together. Our work will provide improved understanding of the controls on contaminant mobility across the CDZ, improve confidence in the safety of geological disposal, and hence assist the UK in the crucial task of disposing of radioactive wastes.

Publications

10 25 50
 
Description The Biogeochemical Gradient and RADionuclide transport (BIGRAD) project was a consortium research grant funded by the Natural Environment Research Council (NERC) between 2010 and 2015. The project was proposed to NERC in response to the UK Government white paper "Managing Radioactive Waste Safely" (MRWS). The principal aim of the project was to develop a better understanding of the geochemical and microbiological evolution of the subsurface environment surrounding a cementitious geological disposal facility (GDF) for intermediate level waste (ILW) in the context of their impacts on radionuclide speciation and fate. The premise of the BIGRAD proposal was that biogeochemical gradients that will develop across the interface between an alkaline, deep GDF and the geosphere are poorly understood and could be important controls on radionuclide behaviour and transport, and thus on the safety and environmental impact of a GDF. The BIGRAD project was conceived and delivered independently of the work and research programme of the Nuclear Decommissioning Authority's Radioactive Waste Management Directorate (NDA-RWMD1) in its implementation of the UK Government's policy. NDA did however participate actively in the project Advisory Group along with the Environment Agency and overseas waste management organisations and research institutes. Overall, the BIGRAD outputs provide underpinning research that broadly supports the arguments made in the generic DSSC regarding the potential beneficial effects of the ADZ on transport properties and radionuclide sorption. Importantly, the project outputs also provide additional lines of evidence supporting mechanisms by which radionuclides may be immobilised in the CDZ and near field, such as those associated with Fe minerals and/or via microbially mediated reduction. In other cases, the project has provided evidence that less cautious assumptions are justified, such as regarding the effects of organic complexants. Collectively, the BIGRAD research project provides strong evidence that increased credit could be taken for microbial and mineralogical processes in the CDZ of a cementitious GDF that may retard radionuclide transport. Considering microbial processes in the CDZ, the BIGRAD research indicates the potential for microbial activity to develop in the pH <11 region of the CDZ, fuelled by hydrogen and soluble organic species released from LLW/ILW. Microbial activity in the CDZ has the potential to further retard the key radionuclides such as Tc, U and Np by bioreduction processes that stablise less mobile reduced forms. In addition, soluble organic complexing species such as ISA may be biodegraded. In this way, and coupled to mineralogical processes promoted by biogeochemical reduction, the CDZ could act as a "bio-barrier" existing outside the hyperalkaline regions of the near field, providing some important additional barriers to radionuclide migration.
In addition to the above implications of the BIGRAD project for the post-closure safety case, the report discusses wider implications of the NERC-funded research on the UK geological disposal programme and the wider scientific community. These include:
? The fundamental value of independent-led research to implementers, regulators and other stakeholders.
? An enduring legacy of training and development of researchers in the UK nuclear community.
? Capability development in synchrotron studies and handling of radioactive samples at Diamond Light Source, including the first analysis in the UK of transuranic elements in environmental samples.
? The scientific legacy in geomicrobiology, radionuclide biogeochemistry, radionuclide mineralogy and colloid behaviour.
? The development of continuing research in these fields, including the NERC Radioactivity and the Environment (RATE) call and the Horizon 2020 Microbiology in Nuclear waste Disposal (MIND) project.
? Significant uplift in the international presence for UK geodisposal research at conferences and international collaborations directly as a result of BIGRAD funding.
Exploitation Route Informing Policy; Delivering new research capability; new people in industry, regulation and academia, see https://rwm.nda.gov.uk/publication/summary-of-the-bigrad-project-and-its-implications-for-a-geological-disposal-facility/
Sectors Education,Energy,Environment

URL https://rwm.nda.gov.uk/publication/summary-of-the-bigrad-project-and-its-implications-for-a-geological-disposal-facility/
 
Description BIGRAD provided a platform for Environmental Radioactivity Research at the University of Manchester and supported the successful award of the NNUF RADER EPSRC grant. BIGRAD provided a platform for University of Manchester (Morris PI) and University of Sheffield (Hyatt PI) to sucessfully tender for the Radioactive Waste Management Research Support Office (https://www.research-support-office-gdf.ac.uk/) BIGRAD has impacted policy through advice to government bodies. The findings of this grant have been used to provide expert advice to government by Professor Francis Livens through membership of CoRWM (http://corwm.decc.gov.uk/) and via membership of the ad hocNuclear R&D Advisory board. There he has provided specific advice relating to his expertise on geological disposal, assistance with public scrutiny on Geological Disposal (CoRWM) and on policy development on Nuclear R&D Advisory board with a particualr remit on R&D needs and geodisposal. In addition, BIGRAD features in NDA-RWMD Science and Technology Plan. "Application of Knowledge gained through BIGRAD." Task 760. Katherine Morris will lead a RWM report on the implications of BIGRAD science to UK policy on waste disposal. Through outreach and facilitating conference sessions eg IGDTP 2014 and Migration 2013 BIGRAD science has improved societal understanding of key UK and global issues and has raised the profile of UK academic science in this area - 20+ presentations at Migration 2013, a conference engagement session and individual contacts with over 300 delegates from across the globe. KM hosted the inaugural IGDTP Geodisposal 2014 conference held inManchester in June 2014. This attracted over 270 delegates from 25 countries. BIGRAD Science featured in 15+ presentations. BIGRAD galvanised the UK capability in synchrotron science with radioactive materials - during BIGRAD's existence, a small low level radiochemistry facility was built and commissioned for sample prep and handling at DIAMOND, active beamline experiments with uranium, technetium and in October 2014 neptunium (the first transuranic analyses on any UK synchrotron facility) have been undertaken and over 10 manuscripts have been published at the time of writing with BIGRAD and DIAMOND acknowledgements. Diamond has now proceeded to develop plans for an intermediate level radioactive laboratory to facilitate access to the range of synchrotron facilities for medium active samples. This would not have been possible without BIGRAD and the scientific team of Law, Lloyd, Morris and Shaw who won access and safety worked with the materials at the facility. The outputs from DIAMOND are underpinning a new understanding of radionuclide mineral reactions and radionuclide biogeochemistry. We have spoken to several thousand academics, members of the public, school children and stakeholders about our geodisposal science. Benefits from these activities are hard to measure, but ad hoc polling of students and members of the public suggest that after engagement with our "radioactivity in the environment" activities, confidence in public safety and management of wastes increases. BIGRAD Science features in a REF impact cases from The University of Manchester detaining the rle of our biogeochemistry work in underpinning models for prediction of radionuclide behaviour in the French safety case.
Sector Education,Energy,Environment,Government, Democracy and Justice
Impact Types Societal,Policy & public services

 
Description Advice to RWM Ltd on microbial aspects of radwaste disposal via invitation to a series of targeted workshops.
Geographic Reach National 
Policy Influence Type Participation in advisory committee
Impact I have advised RWM Ltd on microbial aspects of radwaste disposal via invitation to a series of targeted workshops (including those on gases, complexants, analogue sites) between 2010-present.
 
Description Citation in the NDA-RWMD Science and Technology Plan 2014
Geographic Reach National 
Policy Influence Type Citation in other policy documents
Impact BIGRAD features in NDA-RWMD Science and Technology Plan. "Application of Knowledge gained through BIGRAD." Task 760. Morris will lead a RWM report on the implications of BIGRAD science to UK policy on waste disposal.
URL http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCUQFjAA&url=ht...
 
Description Deputy Chair, UK Government Committee on Radioactive Waste Management (Nov 2007-present)
Geographic Reach National 
Policy Influence Type Membership of a guidance committee
 
Description External advisor, UK Government Decontamination Service
Geographic Reach National 
Policy Influence Type Participation in advisory committee
 
Description Member, Cabinet Office Scientific Advisory Committee (2010-present)
Geographic Reach National 
Policy Influence Type Participation in advisory committee
 
Description Member, NERC Expert Group on Radioactivity in the Environment (2011-2012)
Geographic Reach National 
Policy Influence Type Participation in advisory committee
 
Description Member, UK Government Nuclear R&D Advisory Board (2012)
Geographic Reach National 
Policy Influence Type Participation in advisory committee
 
Description Pareticipation in Advisory Committee
Geographic Reach National 
Policy Influence Type Membership of a guideline committee
Impact Member of EPSRC SAC - review of fusion energy and rebalancing portfolio contributions - advice.
 
Description Prfessor Francis livens- Member, UK Government panel 'Scientific Advice to Government in Emergencies'
Geographic Reach National 
Policy Influence Type Participation in advisory committee
 
Description RCUK Energy Programme Strategic Advisory Committee
Geographic Reach National 
Policy Influence Type Participation in advisory committee
 
Description Biogeochemistry research funded by ANDRA
Amount £4,900 (GBP)
Organisation National Agency for Radioactive Waste Management (ANDRA) 
Sector Public
Country France
Start 03/2013 
End 04/2013
 
Description EPSRC KTA Secondment
Amount £128,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Department Knowledge Transfer Account (University of Manchester)
Sector Academic/University
Country United Kingdom
Start 11/2014 
End 12/2015
 
Description EPSRC KTA Sellafield Bioreduction
Amount £120,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Department Knowledge Transfer Account (University of Manchester)
Sector Academic/University
Country United Kingdom
Start 02/2012 
End 02/2013
 
Description EPSRC Three Dimensional Optical Imaging of Neptunium Redox Speciation: A Feasibility Study.
Amount £250,000 (GBP)
Funding ID EP/R001499/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 03/2017 
End 10/2018
 
Description EU H2020 MIND IGDTP
Amount £400,000 (GBP)
Organisation European Commission 
Department Horizon 2020
Sector Public
Country European Union (EU)
Start 03/2015 
End 03/2018
 
Description EnvRadNet STFC Advanced Network
Amount £22,500 (GBP)
Organisation STFC Laboratories 
Sector Public
Country United Kingdom
Start 08/2016 
End 08/2017
 
Description EnvRadNet2
Amount £400,000 (GBP)
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 03/2016 
End 03/2019
 
Description LLWR - NERC Studentship
Amount £70,000 (GBP)
Organisation Low Level Waste Repository Ltd 
Sector Private
Country United Kingdom
Start 09/2017 
End 04/2021
 
Description NDA Bursary In situ Disposal
Amount £100,000 (GBP)
Organisation Nuclear Decommissioning Authority NDA 
Sector Public
Country United Kingdom
Start 09/2017 
End 04/2021
 
Description NDA Bursary Novel investigation techniques for radioactive discharge pipelines
Amount £100,000 (GBP)
Organisation Nuclear Decommissioning Authority NDA 
Sector Public
Country United Kingdom
Start 09/2018 
End 04/2022
 
Description NDA Studentship Quota
Amount £100,000 (GBP)
Organisation Nuclear Decommissioning Authority NDA 
Sector Public
Country United Kingdom
Start 09/2014 
End 04/2018
 
Description NDA Studentship Quota
Amount £100,000 (GBP)
Organisation Nuclear Decommissioning Authority NDA 
Sector Public
Country United Kingdom
Start 09/2011 
End 04/2015
 
Description NERC Particles
Amount £450,000 (GBP)
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 08/2015 
End 08/2018
 
Description NERC Responsive Mode
Amount £650,000 (GBP)
Funding ID Optical Imaging of Uranium Biotransformations by Microorganisms (OPTIUM) NE/R011230/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 05/2018 
End 06/2021
 
Description NIMMI
Amount £500,000 (GBP)
Funding ID NE/J024732/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 01/2013 
End 01/2016
 
Description National Nuclear User Facility: Radioactive Waste Disposal and Environmental Remediation (RADER).
Amount £2,318,957 (GBP)
Funding ID EP/T011300/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 11/2019 
End 05/2023
 
Description Radioactive Waste Management Research Support Office
Amount £2,500,000 (GBP)
Organisation Government of the UK 
Sector Public
Country United Kingdom
Start 01/2020 
End 12/2024
 
Description STFC Diamond Beamline Access
Amount £630,000 (GBP)
Funding ID SP10163, SP9621, SP9045, SP9841, SP8544, SI8115, SI8114, SP8070, sp8059, sp7593, sp7367, sp4985 
Organisation Diamond Light Source 
Sector Private
Country United Kingdom
Start 01/2010 
End 06/2015
 
Description STFC Funded PhD
Amount £80,000 (GBP)
Organisation Research Councils UK (RCUK) 
Sector Public
Country United Kingdom
Start 09/2013 
End 03/2017
 
Description STFC Network Extension
Amount £400,000 (GBP)
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 03/2016 
End 03/2018
 
Description STFC Network Grant - Env Rad Net
Amount £300,000 (GBP)
Organisation Research Councils UK (RCUK) 
Sector Public
Country United Kingdom
Start 09/2012 
End 09/2015
 
Description STFC, Diamond Light Source. University of Manchester Nuclear Environment and Waste Block Allocation Grant 2.
Amount £900,000 (GBP)
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 01/2017 
End 01/2021
 
Description Sellafield Ltd. PhD on Colloids in Effluent Treatment
Amount £120,000 (GBP)
Organisation Sellafield Ltd 
Sector Private
Country United Kingdom
Start 09/2018 
End 04/2022
 
Description Sellafield Ltd. PhD on Iron Oxide Chemistry and Radionuclide fate in Effluent Treatment
Amount £120,000 (GBP)
Organisation Sellafield Ltd 
Sector Private
Country United Kingdom
Start 09/2018 
End 04/2022
 
Description Summary of the BIGRAD project and its implications for the safety case of a geological disposal facility.
Amount £40,000 (GBP)
Organisation Nuclear Decommissioning Authority NDA 
Sector Public
Country United Kingdom
Start 01/2016 
End 06/2016
 
Title Building Capability for Analysis of Radioactive Samples using XAS / Scattering techniques for the UK 
Description Building capability for analysis of radioactive samples at Diamond Light Source UK. This proposal delivered first analysis of high specific activity radionuclides such as technetium 99, and also high radiotoxicity transuranic elements (Np). 
Type Of Material Improvements to research infrastructure 
Year Produced 2016 
Provided To Others? Yes  
Impact Wider use by the UK radionuclide community of Diamond Light Source Facilities. Capability development. 
 
Description NNL - UoM - Mont Terri 
Organisation National Agency for Radioactive Waste Management (ANDRA)
Country France 
Sector Public 
PI Contribution Lloyd has attracted seed corn from Andra funding to assess the microbial ecology of model bituminised waste systems at elevated pH. This is being developed into a studentship proposal between UoM and Andra.
Collaborator Contribution As part of developing biogeochemical models of the chemical disturbed zone(CDZ) NNL have modelled experiments at the Mont Terri URL that examine the reaction of nitrate as an electron acceptors injected into a borehole within Opalinus clay. The collaboration has enabled the Bigrad biogeochemical and diffusive model of Eh reactions in the CDZ to be developed and tested using multiple tests with added acetate (representing bitumenised waste) and indigenous electron donors. The model forms the basis of larger repository scale model (Small et al Migration Conference, IGD-TP Geodisposal). The modelling is currently reported in Mont Terri Technical reports and a modelling paper is in preparation for Applied Geochemistry to be published alongside other papers describing the in-situ experiment. The European collaborators in this Bitumen-Nitrate-Clay interaction (BN) experiment include waste management organisations, regulators and geomicrobiological research groups from France, Belgium and Switzerland. A consortium has developed from this collaboration that has recently submitted a proposal for Horizon 2020 funding
Impact Small, J. and Abrahamsen, L. BN Experiment: Biogeochemical modelling of the 2nd nitrate injection in Interval 2 (status 2012). Mont Terri Project Technical Note 2012-95. Mont Terri Consortium, St. Ursanne, Switzerland, October, 2012.
Start Year 2012
 
Description BIGRAD ROADSHOW to Crompton House School 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact BIGRAD researcher visited and ran events at Crompton House School

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Year(s) Of Engagement Activity 2013
 
Description Café Scientifique talk at the Royal Society Summer Exhibition 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? Yes
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact More than 500 people (number unknown) listened to Jon Lloyd discuss weather microrganisms can clean up our waste.

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Year(s) Of Engagement Activity 2013
URL http://www.cafescientifique.org/
 
Description Museum of Science and Industry - Meet the Scientist 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact BIGRAD Researchers have spoken to several thousand members of the public at various events. Notable ones include.MOSI Meet the scientist. 2012, 2013, 2014. Footfall of 1000ds members of public.

The event is repeated annually
Year(s) Of Engagement Activity 2012,2013,2014
URL http://www.acbnw2.org.uk/index.php/news-mainmenu/108-npy-meet-the-scientist-day-at-mosi
 
Description Talk on the BBC World News flagship television programme about the group's work on ISA degrading bacteria and nuclear waste 
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 Public/other audiences
Results and Impact Prof JR Lloyd has spoken on the BBC World News flagship television programme about the group's work on ISA degrading bacteria and nuclear waste in Oct 2014, and this work has also been featured on 50+ websites, generating 10s of millions of page views.

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Year(s) Of Engagement Activity 2014