Hydromechanical and Biogeochemical Processes in Fractured Rock Masses in the Vicinity of a Geological Disposal Facility for Radioactive Waste

Lead Research Organisation: Imperial College London
Department Name: Earth Science and Engineering

Abstract

The main goal of this project is to build up expertise and capability in modelling hydromechanical and biogeochemical processes that occur in fractured rock masses in the vicinity of a geological disposal facility for radioactive waste. A consortium of three UK universities will carry out the research, with the expectation of creating durable teams that will continue to collaborate in the future on other radioactive waste projects. The project will bring together researchers with extensive experience in radioactive waste research, as well as others who will bring in key expertise and technologies that were developed in other research fields, such as mining, petroleum engineering, geophysics, or biogeochemistry but are now key to tackling the interdisciplinary problems involved in nuclear waste. The project will also benefit form interactions with leading researchers worldwide, as well as international facilities such as the underground research lab at Grimsel, Switzerland.

The overall project comprises six work packages. Work Package 1 will develop improved methods for estimating the repository-scale hydraulic conductivity of a fractured rock mass, based on geologically realistic fracture network geometries. Work Package 2 will explore and evaluate suitable seismic monitoring strategies, and develop data processing techniques, for the characterisation of potential repository sites. Work Package 3 will examine the key seismic attributes for identifying fracture properties (e.g., fracture density, orientation and stiffness) that play a critical role in repository performance. Work Package 4 will develop coupled thermo-hydro-mechanical models for the behaviour of fractured rock masses. Work Package 5 will model colloid and tracer transport experiments that have been conducted at the Grimsel test site in Switzerland. Work Package 6 will test the importance of biogeochemical processes involving microbes and natural organic matter on actinide mobility in the near-field environment of a nuclear waste repository.

The six work packages are complementary, but are linked to each other in some cases through shared data between, overlapping supervision of PhD students, etc., as described in more detail below. Overall, the project addresses two scientific areas prioritised in the RATE call: Technological innovation for rock mass characterisation at a range of spatial scales, and Biogeochemical coupling, including deep multiphase transport processes. The project involves three UK universities (Imperial College, University of Birmingham, University of Leeds), as well as collaborators from several institutions in the US and Europe.

The main outcomes of this project will be a set of new and/or improved methodologies, codes and protocols for analysing various processes that occur during the lifetime of a repository, or during the site characterisation phase. These methods and tools will be sufficiently flexible and generic to be used in any fractured geological formation that might be investigated as a potential location of a geological repository in the UK. The results and findings of this project will be published in peer-reviewed journals, and presented at appropriate national and international scientific conferences and workshops. Throughout the project, close contact will be maintained, through frequent meetings and visits, with the Nuclear Decommissioning Authority, which is the governmental agency responsible for the safe disposal of nuclear waste.

Planned Impact

The main aim of this consortium is to aid in the capacity building and technology delivery of nuclear storage within the UK, with emphasis on hydromechanics and biogeochemical processes. Thus, it is crucial that the developed knowledge and new technology be made accessible to industry and government. To facilitate this, we will engage with those industries currently working on radioactive waste storage, by making in-house presentations, providing access to white papers and research results, fostering collaboration within and across business sectors, and convening workshops.

The consortium will engage directly with government organisations (e.g., DECC) early on and throughout the project, to identify and define what information is required for policy and regulation, and work with these organisations to help shape new policy and regulations. The outputs of this study will be of direct and lasting benefit to a wide community of regulatory bodies such as EA, SEPA, HSE, FSA, research councils including EPSRC and BBSRC, and NERC Centres including BGS, CEH, and advisory groups such as CoRWM, COMARE, and HPA.

A more comprehensive understanding of hydro-mechanical and biogeochemical processes, and the ability to model these accurately, will be of interest to all the above-listed groups of end-users, because both are fundamental to the safe storage of radioactive waste. Any future accidents and leakage of radioactive contaminants in the groundwater may have a fundamental impact on natural resources, the economy, the standard of living, and the environment.

Societal impact will furthermore be achieved through the numerous collaborations in which the consortium members are involved. The codes that are developed and deployed by the groups will not only be used for studies of nuclear safety, but also for general research into fluid flow, microbes-metal interactions, and rock mechanics. Hence, our methods will have a direct impact in research fields that go far beyond the classical applications of radioactive waste science.

Conferences and Papers: The various research groups will present results every year on key conferences in their fields (e.g., American and British Chemical Society, International Society for Rock Mechanics, etc.) and deliver seminars at academic institutions. We aim to organise special sessions within these conferences. We aim to write comprehensive review articles during the consortium period, to be submitted to high-impact journals, preferably Nature and Science.

Public Outreach: To reach the general public, we will give Nature Live talks at the Natural History Museum (www.nhm.ac.uk/nature-live). We plan to participate in science fairs (Imperial College London and the Royal Society). Via the Imperial Volunteering Centre, we will visit secondary schools in England, and educate high schools about the problems associated with radioactive waste. To reach the wider adult public, we will - in collaboration with the NHM publishing team - create a public science book on the topic Nuclear Waste.

Press and Internet Presence: A primary mechanism of dissemination, throughout the project and beyond, will be through websites. We will use the Imperial Science Press to communicate to the public via the Internet and i-Tunes U.

Scholarship: We plan to incorporate undergraduate students into the project by offering defined MSci projects.

Workshop: We plan to organise two scientific workshops. The theme of the first one will be entitled 'The Hydromechanics of Nuclear Waste in the Near Field' in year 3 and 'The Biogeochemistry of a Nuclear Waste in the Near Field' in year 4. We will invite the various research groups working in the respective research areas and in special nuclear research programs in the United Kingdom (e.g., EPSRC-sponsored Diamond) or Europe (e.g., Euratom) as well as key stakeholders in industry and public service (i.e., Environmental Agency, NDA, Defra).

Publications

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Lang P (2016) Evolution of fracture normal stiffness due to pressure dissolution and precipitation in International Journal of Rock Mechanics and Mining Sciences

 
Description New and improved methodologies, codes and protocols for analysing various processes that occur during the lifetime of a Geological Disposal Facility for radioactive waste have been developed. Interconnected networks of fractures may form the main potential pathways for the transport of radionuclides from the repository to the biosphere. Two different approaches have been taken to model the flow of fluids through networks of rock fractures: effective medium theories (in which the fractured rock mass is 'replaced' by an un-fractured porous continuum that has the same macroscopic permeability as the actual fractured rock mass) and discrete fracture models. Effective medium theories proposed in the literature were used to compare their predictions to the 'exact' permeabilities, as computed by detailed finite element calculations. Input includes matrix permeability, fracture apertures, lengths, orientations, and number densities. Our studies found that extremely accurate permeability estimates could be obtained demonstrating that classical effective medium theories, properly applied, can be used to model the permeability of the fractured rock in the vicinity of a GDF.
Modelling efforts focussed on the generation of geologically realistic fracture networks have generated the first simulations of dense fracture networks that are based on the rigorous computation of stress intensity factors, and the accepted principles of fracture mechanics. A finite element method is used to compute the displacements and stresses around the various fractures, the fractures are then allowed to grow based on whether or not the computed stress intensity factors reach a critical value that depends on rock type. This methodology promises to yield much more realistic fracture geometries than can currently be created using discrete element methods, or heuristic semi-analytical approaches.
Exploitation Route The analytical models for estimating the field-scale hydraulic conductivity of a fractured rock mass, and numerical methods for generating dense fracture networks, that have been developed at Imperial College within the HydroFrame Project will be useful to scientists working in the field of radioactive waste disposal, as well as in areas such as oil and gas production and geothermal energy. These methods have now been published in numerous papers, and presented at many international meetings; the key papers have been cited collectively over 100 times. The geomechanical modelling capabilities that were developed in this project have already led to the funding, by the Swedish Nuclear Waste Management Organisation SKB, of two follow-on projects at Imperial College. These methods will be further enhanced and utilised by researchers at Imperial College, and are also being incorporated into the work of research groups that we have been collaborating with, at the University of Bergen, Wuhan University, and elsewhere.
Sectors Energy,Environment

URL https://link.springer.com/article/10.1007/s11242-016-0685-z
 
Description Horizon 2020 SURE Project
Amount € 5,925,000 (EUR)
Funding ID H2020 654662 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 03/2016 
End 08/2019
 
Description Royal Society University Research Fellowship for Adriana Paluszny
Amount £306,551 (GBP)
Funding ID UF160443 
Organisation The Royal Society 
Sector Academic/University
Country United Kingdom
Start 01/2018 
End 12/2022
 
Title Data on permeability of rock fractures computed by multi-scale models 
Description The permeability of single fractures, pairs of conjugate fracture pairs, and 256 fracture networks, is numerically computed using a multi-scale permeability method. For fracture networks, the geometries of the files are contained in 3dm files. The results are presented in a series of json text files. The method to compute permeabilities is described in the PhD thesis entitled "Multi-scale modelling of thermohydro-mechanical-chemical processes in fractured rocks" by Philipp Lang, Imperial College London, supervised by Adriana Paluszny and Robert W. Zimmerman. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact The main paper based on this data, "Permeability tensor of three-dimensional fractured porous rock and a comparison to trace map predictions", P. S. Lang, A. Paluszny, and R. W. Zimmerman, J. Geophys. Res. Solid Earth, vol. 119, pp. 6288-6307, 2014, has been cited 83 times in the open literature. 
URL http://www.bgs.ac.uk/discoverymetadata/13607330.html
 
Title Data supporting the publication "Inclusion-based effective medium models for the permeability of a 3D fractured rock mass", Transport in Porous Media, 2016 
Description This is the data supporting Fig. 4 of the publication: Ebigbo, A., Lang, P. S., Paluszny, A., and Zimmerman, R. W. (2016). Inclusion-based effective medium models for the permeability of a 3D fractured rock mass. Transport In Porous Media, DOI: 10.1007/s11242-016-0685-z. It contains numerically computed permeabilities for various realisations of fracture networks. There are six different cases (as explained in the paper). 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact The paper based on this data set has been cited 23 times since its publication 
URL http://www.bgs.ac.uk/discoverymetadata/13606923.html
 
Title Data supporting the publication "Quantification of fracture interaction using stress intensity factor variation maps", Journal of Geophysical Research: Solid Earth, 2017. 
Description Fracture interaction data supporting Thomas et al. 2017. Quantification of fracture interaction using stress intensity factor variation maps. JGR: Solid Earth. Data supporting the publication: Thomas R. N., Paluszny A., Zimmerman R. W., 2017. Quantification of fracture interaction using stress intensity factor variation maps. Journal of Geophysical Research: Solid Earth [DOI: 10.1002/2017JB014234]. Each sheet contains the data used in each figure, covering method validation, stress intensity factor perturbations, and data used to create fracture interaction maps. The data were created using the Imperial College Geomechanics Toolkit. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact The Imperial College research group that generated this dataset has been contacted by several international research groups (MIT, Purdue University), to discuss possible research collaborations that make use of the same computational technology that generated this dataset. 
URL http://www.bgs.ac.uk/discoverymetadata/13607185.html
 
Description Collaboration between ICL and NNL on cracking of fuel pins 
Organisation National Nuclear Laboratory
Country United Kingdom 
Sector Public 
PI Contribution Imperial College researchers Adriana Paluszny and Robin Thomas used the Imperial College Geomechanics Toolkit to model the permeability of cracked fuel pins from Advanced Gas-cooled Reactors.
Collaborator Contribution NNL scientists David Hambley and Frazer Hawthorne provided high-resolution optical microscopy images of cracked fuel pins.
Impact This collaboration has led to one journal paper: "Permeability of observed three dimensional fracture networks in spent fuel pins", R. N. Thomas, A. Paluszny, D. Hambley, F. M. Hawthorne, R. W. Zimmerman, J. Nucl. Maters., vol. 510, pp. 613-632, 2018. https://www.sciencedirect.com/science/article/pii/S0022311518304677
Start Year 2016
 
Description Collaboration with Stanford University on spectroscopy and radiochemistry 
Organisation Stanford University
Department Stanford Synchrotron Radiation Lightsource
Country United States 
Sector Academic/University 
PI Contribution Janice Kenney trained in XAS spectroscopy at SLAC, and Matthew Kirby trained in anaerobic column experiments
Collaborator Contribution Stanford supplied training in experimental methods, and access to advanced equipment.
Impact Data collected by ICL researchers at Stanford have been reported within the HydrFrame RATE project, and presented at various international scientific conferences.
Start Year 2016
 
Title Thermo-elastic capabilities added to SOLIDITY code 
Description Heat conduction and thermo-elastic capabilities were added to the Finite-Element / Discrete-Element code "SOLIDITY". 
Type Of Technology Software 
Year Produced 2019 
Open Source License? Yes  
Impact The enhancements to this code have already led to a six-month PhD studentship extension for Clement Joulin, funded by SKB. 
URL http://solidityproject.com/
 
Description Adriana Paluszny gave a talk at the 2018 Computational Methods in Water Resources Conference, in Saint-Malo, France, on 6 June 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Adriana Paluszny gave a talk entitled "Permeability tensor of three-dimensional fractured porous rocks and fracture pattern growth", at the 2018 International Conference on Computational Methods in Water Resources, in Saint-Malo, France, on 6 June 2018
Year(s) Of Engagement Activity 2018
URL http://cmwrconference.org/
 
Description HydroFrame Summer School on Radioactive Waste Disposal 
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 The HydroFrame Summer School on Radioactive Waste Disposal took place from 8-12 August 2016. The first three days, in London, included talks by UK and international experts, presentations by HydroFrame researchers, a poster session open to all RATE researchers, and computer workshops in geochemical modelling, groundwater flow and transport modelling, and discrete fracture geomechanics. The highlight of the school was a field trip to the Grimsel Underground Rock Laboratory in Switzerland. The school was attended by over thirty PhD students and researchers from twelve UK universities.
Year(s) Of Engagement Activity 2016
 
Description John-Paul Latham gave a presentation at the International Conference on Coupled Processes in Fractured Geological Media in Wuhan, China, 12 November 2018. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact John-Paul Latham presented an Invited Talk entitled "Recent advances in hydro-mechanical modelling of fractured rocks using the finite-discrete element method" at the International Conference on Coupled Processes in Fractured Geological Media (CouFrac) in Wuhan, China, 12 November 2018.
Year(s) Of Engagement Activity 2018
URL https://www.coufrac2018.com/
 
Description Matthew Kirby gave a poster presentation at the International Migration Conference, Barcelona, 10-15 September 2017. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Matthew Kirby gave a poster presentation entitled "A density functional theory approach to predicting uranium mobility in the subsurface in the presence of organic ligands", at the International Migration Conference, Barcelona, 10-15 September 2017.
Year(s) Of Engagement Activity 2017
URL https://www.migration2017.org/
 
Description Nature Live presentation 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Two researchers (DW and RT) gave a Nature Live presentation at the Natural History Museum, entitled "Managing Radioactive Waste Safely", on 24 February 2017. The presentation sparked numerous questions from the forty audience members, and discussion afterwards.
Year(s) Of Engagement Activity 2017
URL http://www.nhm.ac.uk/events/managing-radioactive-waste-safely.html
 
Description Nine researchers from the Imperial College HydroFrame project attended the Radioactivity and the Environment (RATE) meeting at Central Hall Westminster from 15-17 January 2018. 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact Nine Imperial College researchers from the HydroFrame project attended the Radioactivity and the Environment (RATE) meeting at Central Hall Westminster from 15-17 January 2018. PhD student Robin Thomas gave an oral presentation entitled "Numerical modelling of the permeability of fractured rock masses". Other attendees (Clement Joulin, Matt Kirby, JP Latham, Adriana Paluszny, Vasia Tsaparli, Dominik Weiss and Jason Xiang) presented posters and/or exhibits. The meeting attracted over 100 attendees, including academic and industrial researchers, and representatives of UK and overseas funding and regulatory agencies.
Year(s) Of Engagement Activity 2018
URL https://www.bgs.ac.uk/rate/finalScienceMeeting.html
 
Description Presentation by Dominik Weiss at the International Migration Conference, Barcelona, 10-15 September 2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Dominik Weiss presented a talk entitled "Uranium (VI) Mobility through Heterogeneous Quartz Sand between pH 10.5 and 12.5 and with 0 to 0.3 M Sodium Chloride" at the International Migration Conference, Barcelona, 10-15 September 2017.
Year(s) Of Engagement Activity 2017
URL https://www.migration2017.org/
 
Description Presentation by JP Latham at the 16th MIR Conference in Mechanics and Engineering in Rock, Torino, Italy, 16-17 February 2017. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact John-Paul Latham gave a talk entitled "Modelling hydro-geomechanical behaviour of fractured and fracturing rock masses: application to tunnel excavation-induced damage" at the 16th MIR Conference in Mechanics and Engineering in Rock, Torino, Italy, 16-17 February 2017.
Year(s) Of Engagement Activity 2017
URL http://www.symposium.it/eventi/2017/16-ciclo-di-conferenze-di-meccanica-ed-ingegneria-delle-rocce
 
Description Presentation by JP Latham at the Swedish National Geosphere Laboratory's Underground Space Challenge Conference in Kalmar, Sweden on 11-12 October 2016. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact John-Paul Latham gave an invited talk entitled "Application of FEMDEM models to the hydro-geomechanical behaviour of fractured and fragmented rocks including effects of fracture propagation and large rock displacement" at the Swedish National Geosphere Laboratory's Underground Space Challenge Conference in Kalmar, Sweden on 11-12 October 2016.
Year(s) Of Engagement Activity 2016
URL http://www.novaoskarshamn.se/en/Conferences-and-seminars/2016-NGL-Annual-Science-Meeting.aspx
 
Description Presentation by Robin Thomas at the 2016 Fall Annual Meeting of the American Geophysical Union, San Francisco, 15 December 2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Robin Thomas presented a poster entitled "Permeability of three-dimensional rock masses containing geomechanically grown anisotropic fracture networks" at the 2016 AGU Fall Meeting in San Francisco on 15 December 2016. The poster was well attended, and generated much discussion, including plans by researchers from MIT to visit Imperial College and initiate collaboration on fractured rock modelling.
Year(s) Of Engagement Activity 2016
URL https://agu.confex.com/agu/fm16/mediafile/Handout/Paper134321/AGU%20Robin%20N%20Thomas%20H51C-0825.p...
 
Description Presentation by Robin Thomas at the 9th International Conference on Porous Media, Rotterdam, 8-11 May 2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Robin Thomas gave a presentation entitled "Change in three-dimensional rock mass permeability during the growth of geomechanical fractures" at the 9th International Conference on Porous Media, Rotterdam, 8-11 May 2017. The presentation was attended by over 100 participants at this scientific conference.
Year(s) Of Engagement Activity 2017
URL https://www.interpore.org/events/interpore-conference-programs/9th-international-conference-on-porou...
 
Description Robin Thomas gave a talk at the Swedish Nuclear Fuel and Waste Management Company on 5th October 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact Robin Thomas visited the Swedish Nuclear Fuel and Waste Management Company (SKB) and the Royal Institute of Technology (KTH) in Stockholm, on 4th-5th October, and gave a talk entitled "Geomechanical discrete fracture modelling: 3D growth and coupled processes", describing some of the research that he has been doing with Adriana Paluszny and Robert Zimmerman, as part of the NERC-funded HydroFrame project.
Year(s) Of Engagement Activity 2018