Platform for Long-term Experimental Investigation of Alteration in Disposal Environments and Storage - PLEIADES

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

Abstract

PLEIADES will establish essential research infrastructure to underpin the development of decommissioning, interim storage and disposal safety cases for radio-materials arising from legacy, new build and future nuclear fuel cycles. It will enable research in 3 key areas of government policy relating to nuclear energy:

1. Geological disposal: The success of HM Government's nuclear decommissioning responsibilities and its future new build ambitions rests upon the successful implementation of policy to deliver a geological disposal facility (GDF) for radioactive waste. It is necessary to demonstrate that post-closure safety of a GDF will be maintained before it can be built. This requires an understanding of long-term corrosion rates and degradation mechanisms of waste, under GDF conditions, which PLEIADES will be uniquely placed to provide.

2. Reduce hazard of legacy nuclear sites: The risks and hazards of decommissioning the UK's nuclear legacy are the most challenging in the world. During decommissioning, radioactive wastes are converted into a form that can be safely stored for many decades. During storage, the waste materials should not change or degrade, however, there are many that are subject to corrosion. The equipment within PLEIADES will have the capability to determine the corrosion processes and rates of such radio-materials, informing safety cases for interim storage and subsequent decisions about future management practice.

3. Accelerate nuclear decommissioning: It was recently announced that the preferred solution to deliver savings of 20% in the £120 billion cost of nuclear decommissioning to the UK taxpayer, by 2030, is the development of at least one Near Surface Disposal (NSD) facility. Disposal of waste in NSD could dramatically reduce decommissioning timescales. Pivotal to its success of this new approach is an appraisal of NSD safety, including models of radioactive waste degradation over the 100s of years of disposal. PLEIADES has the capability to address critical knowledge gaps in corrosion and radionuclide release rates from waste in such facilities and, therefore, to support accelerated implementation of NSD.

PLEIADES will be a unique facility in the UK, enabling research that addresses key gaps in capability that were identified by the academic community and radioactive waste management industry:

> Corrosion in sub-surface disposal conditions: Because radio-materials are highly sensitive to atmospheric conditions it is essential that sub-surface disposal environments are replicated in the laboratory. Only if the correct conditions are maintained during corrosion experiments will meaningful data be obtained. The PLEIADES equipment will enable such research on a wide range of radio-materials, for which is there is no current UK capability.
> Long-term corrosion: A unique aspect of PLEIADES is the capability to establish long-term (decades) corrosion experiments under stable conditions representative of sub-surface environments, giving detailed insight to slow degradation processes. With less than 20y remaining until a GDF will be constructed, the establishment of long-term experiments is essential now, if we are to understand the science behind radioactive waste corrosion.
> Corrosion within a radiation field: Corrosion processes of radio-materials can be significantly influenced by the effects of radiation. These effects are currently poorly understood because there is a paucity of facilities that enable their investigation. PLEIADES will constitute the only UK university facility with capability for analysing highly radioactive materials that create their own radiation field, and the PLEIADES equipment is compatible other user facilities that will enable corrosion experiments to be performed within an external radiation field.

Publications

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Walling S (2023) Stability of SrCO3 within composite Portland-slag cement blends in Cement and Concrete Composites

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Smith H (2022) Cr2+ solid solution in UO2 evidenced by advanced spectroscopy. in Communications chemistry

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Mansfield J (2023) Localised extended ("vermiform") features formed during glass dissolution in Journal of Non-Crystalline Solids

 
Description Research undertaken in the PLEIADES facility has been significantly disrupted by the relocation of the PI to another institution. The original institution held the equipment hostage for 7 months (ongoing) while negotiations over equipment and grants is ongoing. We anticipate that these negotiations will be complete by May 2024, with the PLEIADES facility relocating to the University of Bristol. Prior to this, PLEAIDES was supporting several aspects of the national programme to develop appropriate end states for radioactive waste, including geological disposal, near surface disposal and in-situ disposal. For example, we were developing a comprehensive understanding of the kinetics and mechanisms of radioactive waste leaching into groundwater, including vitrified high level waste, cementitious waste, spent nuclear fuel and ceramic materials for plutonium disposition. With the eventual installation of the glovebox facility (due to be in Bristol in September 2024), we will establish critical UK capability for long-term leach testing, an essential requirement for the development of post-closure safety assessments and permitting of a geological disposal facility for radioactive waste. One key area of work has been the development of leaching protocols for titanate ceramic materials and "disposal-MOX", both candidate materials for the immobilisation and disposal of the UK's 140 teHM inventory of PuO2. The research is being used to gather an evidence base for a government decision on the long-term management of PuO2 later in the decade. Changing the policy to one of disposal has the potential to save the tax payer £100m per year in PuO2 storage costs.
Sector Energy,Environment,Government, Democracy and Justice
Impact Types Societal

Policy & public services

 
Description CoRWM SMR / AMR report
Geographic Reach National 
Policy Influence Type Implementation circular/rapid advice/letter to e.g. Ministry of Health
Impact The major outcomes of the publication thus far are: (1) better informed civil service members (2) decision by Great British Nuclear to include management of radioactive waste in the next phase of the SMR competition Other impacts include bringing together a wide range of relevant stakeholders (e.g. NDA, NWS, EA, ONR, GBN etc. to discuss the issue of radioactive waste management in new nuclear reactors).
URL https://www.gov.uk/government/publications/development-of-small-modular-reactors-smrs-and-advanced-m...
 
Description Oral Evidence at the Science, Innovation and Technology Committee inquiry on Delivering Nuclear Power
Geographic Reach National 
Policy Influence Type Contribution to a national consultation/review
Impact The evidence given has been used to strengthen government policy on the geological disposal of radioactive waste in the UK, as well as underpin further enquiry into public spending on nuclear decommissioning.
URL https://committees.parliament.uk/work/6864/delivering-nuclear-power/news/196805/strategic-plan-neede...
 
Description Participation in South Copeland community events
Geographic Reach Local/Municipal/Regional 
Policy Influence Type Participation in a guidance/advisory committee
Impact Members of the Community Partnership have sought further advice from me, and have reported a change in attitude about the geological disposal of radioactive waste in their community.
 
Description Development of disposal-MOX
Amount £10,000 (GBP)
Organisation Orano 
Sector Private
Country United States
Start 07/2022 
End 03/2023
 
Title Stirred-Reactor Coupon Analysis test 
Description Previously in the nuclear waste performance community, the single-pass flow-through (SPFT) method ASTM C1662 (e.g., ASTM C1662-18 2018) has been the most common test chosen to evaluate waste form corrosion in dilute conditions. The test method consists of a target solution passed at a relatively low flow rate over a sample material (usually in particle form) and measuring the composition of the effluent by solution analyses. The typical analytical techniques for solution analyses have detection limits that can require lowering flow rates (and thus decreasing the dilution of the contacting solution) just so the concentration of ions in the resultant sample is high enough to measure. This higher concentration impacts the resultant measured rate to the extent that extrapolations of multiple measurements must be made to estimate the dissolution rate in infinitely dilute conditions. A new technique, termed the stirred-reactor coupon analysis (SRCA) method, has been developed to achieve solution dilution through a large, well-mixed volume rather than via solute flow. In this method, monolithic glass coupons are masked with an inert material before undergoing corrosion in a large volume of solution with known chemistry and temperature for a pre-determined duration. After terminating the test, the mask is removed and the step height difference between the protected and corroded portions of the sample coupon is measured to determine the extent of glass dissolution. The step height can be converted to a rate measurement using the test duration and glass density. 
Type Of Material Improvements to research infrastructure 
Year Produced 2022 
Provided To Others? No  
Impact The method will be developed into an ASTM standard for application to understanding the durability of radioactive waste in geological disposal environments. 
 
Description Partnership with HZDR ROBL 
Organisation Helmholtz Association of German Research Centres
Department Helmholtz-Zentrum Dresden-Rossendorf
Country Germany 
Sector Academic/University 
PI Contribution Partnership is focused on developing techniques and samples to elucidate the chemistry of uranium-based nuclear fuels. My team have contributed materials for this effort.
Collaborator Contribution Our partners at HZDR have contributed access to the ROBL beamline to advance understanding of uranium chemistry in nuclear fuels -- they have used their in-house beamtime for this.
Impact A number of publications have arisen from this partnership, with more in the pipeline. We are preparing a large collaborative EU grant together.
Start Year 2022
 
Description BBC Look North interview with Peter Levy 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Media (as a channel to the public)
Results and Impact Interview with Peter Levy on the 6.30pm BBC Look North evening news, about the proposed siting of a geological disposal facility for radioactive waste at the Theddlethorpe site.
Year(s) Of Engagement Activity 2023
 
Description BBC Radio Scotland Interview 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Media (as a channel to the public)
Results and Impact Interview on BBC Radio Scotland about the potential radioactive waste issues at the Zaporizhzhia nuclear power plant.
Year(s) Of Engagement Activity 2023
 
Description Careers talk at Diamond Light Source 
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 I gave a talk about my career at the Diamond Light Source 2023 Early Career Scientist's Symposium, sparking questions about a career in the nuclear industry, and in academia.
Year(s) Of Engagement Activity 2023
URL https://www.diamond.ac.uk/Home/Events/2023/Early-Career-Scientists-Symposium-2023.html
 
Description Experimental User community workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact A day-long webinar describing the capabilities and research outputs of the National Nuclear User Facilities -- PLEIADES, HADES, EXACT and RADER -- was held. Approximately 40 people (postgrad students, academic staff, regulators and nuclear industry representatives) attended to learn about how to access the facilities.
Year(s) Of Engagement Activity 2022
 
Description Geology Bites podcast 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Participated in the Geology Bites podcast, talking about the geological disposal of radioactive waste.
Year(s) Of Engagement Activity 2024
URL https://www.geologybites.com/claire-corkhill
 
Description Interview with Joe Pinkstone at The Telegraph 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Interview with The Telegraph: Long search for place to bury highly radioactive nuclear waste begins
Year(s) Of Engagement Activity 2023
URL https://www.telegraph.co.uk/news/2023/06/27/nuclear-waste-undersea-storage-geological-disposal-facil...
 
Description Interview with Rachel Millard at The Telegraph 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Interview with The Telegraph: "Inside the battle to stop radioactive nuclear waste from contaminating Britain"
Year(s) Of Engagement Activity 2023
URL https://www.telegraph.co.uk/business/2023/04/16/nuclear-radioactive-windscale-sellafield-accident/
 
Description Interview with Theo Legett on BBC World Service Business Daily 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact I was interviewed by Theo Leggett for a documentary on the BBC World Service's Business Daily podcast, titled "How to shut down a nuclear power station". This reached a large international audience and described why it is so difficult, and takes so long, to decommission a nuclear power plant.
Year(s) Of Engagement Activity 2024
URL https://www.bbc.co.uk/programmes/w3ct4n0b
 
Description Letter to the Editor of The Times 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Letter to the Editor of The Times, "Nuclear waste cannot be ignored"
Year(s) Of Engagement Activity 2023
URL https://twitter.com/clairecorkhill/status/1643900472732819457/photo/1
 
Description Panelist on BBC R4 Start the Week 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact I participated in a panel discussion on BBC Radio 4's flagship cultural programme, Start the Week, with a focus on glass materials ("Made out of glass"). I spoke about the immobilisation of radioactive waste in glass, amongst other applications of glass. I received lots of follow-on questions from the public, as well as requests from museums and artists for help with glass materials / exhibits.
Year(s) Of Engagement Activity 2024
URL https://www.bbc.co.uk/programmes/m001vs75
 
Description Participation in panel on geological disposal facility siting 
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 100 postgraduate students and professionals in the nuclear industry attended a panel session (of which I was a member) about the siting of a geological disposal facility for radioactive waste. This sparked a range of questions and increased interest in the topic.
Year(s) Of Engagement Activity 2024
 
Description Participation in the MRS 2022 Scientific Basis for Nuclear Waste Management Conference 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact A virtual session of the MRS 2022 conference was organised for the Scientific Basis for Nuclear Waste Management Symposium, which was also recorded and available for all conference participants to view for 28 days.
Year(s) Of Engagement Activity 2022
 
Description Preparation of poster for Plutonium Futures 2022 Conference 
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 Poster presentation at an international conference, this disseminated the research to other academics, as well as industrial partners who are interested in Pu science and underpinning Pu disposal policy.
Year(s) Of Engagement Activity 2022
 
Description Preparation of presentation for the NWS RSO Conference 2023 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact The Conference is designed to bring together industrial partners and academics working in collaboration with NWS, to share the latest research regarding the disposal of nuclear waste in the UK.
Year(s) Of Engagement Activity 2023
 
Description Sky News Interview 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Sky News interview: Nuclear waste: Public to have a say on plans to bury radioactive material
Year(s) Of Engagement Activity 2023
URL https://news.sky.com/story/nuclear-waste-public-to-have-a-say-on-plans-to-bury-radioactive-material-...