CNSC research on geologic repositories

As the Canadian nuclear regulator, the Canadian Nuclear Safety Commission (CNSC) is responsible for licensing geologic repositories intended to provide for the long-term management of radioactive waste.

Background on geologic repositories

A geologic repository is constructed underground, usually at a depth of several hundreds of meters or more below the surface in a stable host rock.

In Canada, there are two long-term radioactive waste management initiatives underway that may result in the construction of geologic repositories.

The first is Ontario Power Generation’s deep geologic repository for low-and intermediate-level radioactive waste from the Bruce, Pickering and Darlington nuclear generating stations.

The second initiative is the Nuclear Waste Management Organization’s Adaptive Phased Management project for the long-term management of Canada’s used nuclear fuel.

Schematic of the OPG DGR project

Schematic of the OPG DGR project

CNSC regulatory research

Since 1978, the CNSC has been involved in independent and internationally collaborative research focusing on long-term safety issues related to the disposal of radioactive waste and used nuclear fuel in sedimentary rock. Geological repositories rely on multiple barriers (for example, the waste form, container, engineered seals, and host rock) for the long-term containment and isolation of radioactive waste. Therefore, the CNSC’s research program looks at the long-term performance of those barriers.

nuclear fuel storage

In Canada, used nuclear fuel is currently safely stored in interim storage facilities.

This research program consists of independent scientific research conducted by CNSC staff in collaboration with national and international institutions, such as Canadian universities, the BGR (German Geological Survey), IRSN (Institut de Radioprotection et Sûreté Nucléaire, France) and CANMET (Canada Centre for Mineral and Energy Technology). This collaboration has provided CNSC staff with invaluable experimental data obtained from laboratory and field tests that are used in the development and validation of mathematical models.

It also includes the monitoring and critical review of state-of-the-art scientific advancements and staff participation in international forums to exchange information about geological repositories.

The program helps in the development and update of regulatory documents that form the basis for CNSC staff recommendations to the Commission on geological repositories for radioactive waste.

The CNSC’s research is not meant to duplicate research done by the project applicant, but rather to identify gaps in information, and to verify key safety aspects related to geological repositories.

Core sample room

Core sample room

Research results

  • View the CNSC timeline: “The science behind safe nuclear waste disposal: decades of research” New Printable version
  • Research activities from 1978 to 1996 focused on the suitability of granitic Canadian Shield rocks to host this type of repository.

    Research activities from 1996 to 2008 continued on granitic rock, with the addition of projects on the long-term performance of engineered seals.

    Research activities from 2009 to the present expanded to include an understanding of the potential for a geological repository within sedimentary rock, so that CNSC staff are prepared to assess any future proposal involving geological repositories in either rock type. The current research projects also look at waste characteristics and engineered barriers (in particular the sealing materials). Natural analogues are natural examples of materials found in or processes caused by geological repositories. High-grade uranium deposits such as Cigar Lake are examples of natural analogues; they prove that radionuclides can be contained within favourable geological formations for up to billions of years. CNSC staff are also currently performing research on natural analogues.

    The results of CNSC’s regulatory research program have been published in peer-reviewed journal papers, reports, conference abstracts and papers, and workshops.

    Future research projects will focus on waste characteristics, engineered barriers (in particular the sealing material), and geosphere issues.

    The CNSC will continue to collaborate with the BGR, the IRSN, CANMET, and Canadian universities carrying out experimental and theoretical research on the performance of engineered and natural barriers.

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    Grimsel Test Site, underground research and development URL, Switzerland

    Grimsel Test Site, underground research and development URL, Switzerland

    Participation in international projects

    Participation in international projects allows staff to maintain their knowledge and competence by keeping up to date with international state-of-the-art science, practices and regulations.

    It increases the CNSC’s visibility, since CNSC staff contribute actively to those projects by sharing their knowledge, acting as team leaders, and by contributing to the writing and/or peer review of project documents.

    Below are brief descriptions of international projects in which CNSC staff have participated.

    IGSC (Integration Group for the Safety Case)
    The IGSC is the main technical advisory body to the Nuclear Energy Agency (NEA) Radioactive Waste Management Committee on the deep geological disposal of long-lived and high-level radioactive waste. The objective of the IGSC is to monitor scientific advancements related to developing a safety case. The IGSC organizes annual plenary and specialized workshops on specific subjects (e.g., gas generation and migration, monitoring for the performance of a repository). CNSC staff contribute actively by giving presentations and discussions on specific subjects.

    SITEX (Sustainable network of independent technical expertise for radioactive waste disposal)
    SITEX is a project within the Seventh Framework Program of the European Atomic Energy Community (Euratom). The objective of SITEX is to establish a sustainable network of technical support organizations and regulatory bodies with the goal of harmonizing European and international approaches to reviewing safety cases. The CNSC participates in working groups looking at the development of guidance documents, regulatory research and planning for the review of safety cases.

    DECOVALEX
    DECOVALEX, an international project that started in the early 1990s, compares modelling results for the performance of seals and host rocks using experimental data from underground research laboratories and other experimental facilities. The CNSC has been an active participant in DECOVALEX since its beginning.

    GEOSAF – International Project on Demonstrating the Safety of Geological Disposal
    The GEOSAF project was initiated in 2008 by the IAEA with the objective of harmonizing approaches for preparing a safety case with a special emphasis on the expectations of regulator authorities with respect to the development of the safety case. GEOSAF provides a forum to exchange ideas and experience in developing and reviewing the safety case. Through GEOSAF, the CNSC contributes to the development and finalization of IAEA guidance documents on radioactive waste safety.

    Underground Research Facilities (URF) Network for Geological Disposal
    This IAEA program provides an overview and general update of experimental programs in all URFs that are part of the network at annual network meetings. The CNSC contributes on regulatory guidance and receives access to expert information and training.

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    HIDRA working group

    HIDRA working group

    HIDRA Project – IAEA Human Intrusion in the context of Disposal of Radioactive Waste
    The CNSC participates in and contributes to the project to provide recommendations to clarify existing IAEA requirements and guidance relevant to the assessment of future human actions and human intrusion.

    Published regulatory research on geological disposal of radioactive waste

    1. Research activities from 1978 - 1996

    In 1978, the governments of Canada and Ontario announced the Nuclear Fuel Waste Management Program. Under this program, Atomic Energy of Canada Ltd. (AECL) was directed to develop the concept of deep geological disposal of used nuclear fuel (UNF) at depths of hundreds of metres in a rock formation.

    AECL focused on crystalline rock (rocks that are formed of crystallized minerals, for example granite) in the Canadian Shield, with the host rock as the major barrier to radionuclide movement from the emplaced used fuel.  The Atomic Energy Control Board (AECB) – the Canadian nuclear regulator at that time – began its own research to be able to confirm the feasibility of the disposal concept. The focus of the regulatory research was on the host rock and its long term performanceFootnote 1 Footnote 2 Footnote 3 Footnote 4 Footnote 5 Footnote 6 Footnote 7 Footnote 8 Footnote 9 Footnote 10 Footnote 11 Footnote 12 Footnote 13 Footnote 14 Footnote 15 Footnote 16 Footnote 17 Footnote 18 Footnote 19 Footnote 20 Footnote 21 Footnote 22 Footnote 23. The main findings from the regulatory research follow.

    • Uranium ore bodies that formed billions of years ago and remain stable today, such as the high grade Cigar Lake deposit in northern Saskatchewan, owe part of their long term stability to the geochemical conditions of the groundwater which help to prevent the oxidation and mobilization of uranium . The above conditions are defined as reducing conditions. Other uranium ore deposits have remained stable even under relatively oxidizing (as opposed to reducing) groundwater conditions, where the extent of uranium remobilization was limited (as documented for the shallower Alligator River deposits in Australia) by uranium sorption onto secondary iron oxides within that aquiferFootnote 1.
    • The groundwater at depths of more than a few hundred of meters in crystalline rocks of the Canadian Shield are both very oldFootnote 2 (at least 10,000 years old) and salineFootnote 3.
    • While the construction of a repository would be on the same scale as several mines, the mass of the used fuel that would be disposed of within a repository is very small in comparison with the mass of the material that would be involved in excavating the repository and establishing the engineered barriers. A used fuel repository would have a similar geochemical impact on the geosphere as a uranium ore depositFootnote 5.
    • The radiotoxicity of the used nuclear fuel would be comparable to a low-grade (0.1%) uranium ore body after a few tens of thousands yearsFootnote 6 Footnote 7.
    • The main agent of radionuclide transport is groundwater. Mathematical modellingFootnote 8 Footnote 9 confirmed that with proper site selection and engineering design, the rate of groundwater flow in the vicinity of the repository would be very slow.
    • Since the main barrier in the AECL’s concept was the host rock, a mathematical model was developed to assess the long term evolution of the host rockFootnote 11 Footnote 12 Footnote 13 Footnote 14 Footnote 15 Footnote 16 Footnote 17 Footnote 18 Footnote 19 Footnote 20 Footnote 21 Footnote 22. The model takes into account the complex interaction between the heat generated from the used fuel, the mechanical response of the rock and the movement of the groundwater.
      • The model was extensively verified with analytical solutions and validated against experimentsFootnote 11 Footnote 12 Footnote 13 Footnote 15 Footnote 17 Footnote 18 Footnote 19 Footnote 20 Footnote 39 Footnote 48
      • It was used to assess the robustness of the host rock against earthquakesFootnote 22, glaciationFootnote 21and the effects of the heat generated from the used fuelFootnote 14 Footnote 16. It was found that the host rock is a very efficient barrier against radionuclides migration when relatively unfractured. Used nuclear fuel should be emplaced in such type of rock at a minimum distance from a major fracture zone. That minimum distance depends on the specific characteristics of the rock. It was emphasized that in practice it could be difficult to verify that requirement; therefore there should be more reliance on the engineered barriers in order to provide additional and redundant safety features.

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    How the regulatory research was used

    Based on the independent regulatory research, assessment, and international collaboration, the AECB was able to conclude that although there were deficiencies in the way it was demonstrated the AECL’s concept was feasible and that Canada should move beyond the concept assessment stage and start to select a site. The AECB submitted its reportFootnote 23 to the Seaborn Panel, the federal environmental assessment review panel established to review the AECL concept.

    2. Research activities from 1996-2008

    During this period, the AECB and its successor the Canadian Nuclear Safety Commission (CNSC) (from 2000) continued regulatory research in geological disposal in order to keep up-to-date with new technological and scientific developments. The research activities were conducted in collaboration with national and international organizations and consist of the following:

    • Research on the geochemistry of Canadian Shield groundwater continued. The groundwater is distinctly zoned: salinity increases with depth and the groundwater composition evolves from relatively fresh in the shallower crust above ~300m, becoming increasingly brackish with depth. The increased salinity at depth indicates that the groundwater is very old and had not mixed with fresh water from the surface; this in turn suggests that the rate of groundwater movement at depth is very slow. These brines likely infiltrated the Shield 300 – 400 million years ago. Lithium isotopes were used to distinguish the origins of ancient brines derived from a variety of marine sourcesFootnote 24. Geochemical and isotopic data were further used to investigate the ancient origin of Shield brines, from Paleozoic sedimentary rocksFootnote 25.
    • The AECB/CNSC participated in the DECOVALEX projectFootnote 43.  DECOVALEX is an international collaborative consortium. DECOVALEX gathered research teams from many countries, to interpret experimental data from Underground Research Laboratories (URL) through the development and validation of mathematical models.
    • Research on the long term performance of crystalline rock (similar to Canadian Shield’s rock) continued. The potential damage to the rock, its extent and characteristics, were studied, using experimental data from small-scale experimentsFootnote 34 Footnote 50, but also from URL such as the Kamaishi Mine, in JapanFootnote 35, the URL in Whiteshell, Canada Footnote 28 Footnote 40 Footnote 41, and the Grimsel URLFootnote 47 Footnote 49, Switzerland. In general, it was shown that damage due to excavation and heat generated from the used fuel is confined in small zones around the excavated zones. However, the permeability in that damage zone can constitute faster pathways for radionuclide migration. The design and safety assessment of geological disposal repositories must take the damage zones into consideration.
    • Research on the long term performance of bentonite seals was started. Bentonite is a clay that is added around the container as another barrier.
      • A model for determining the complex interaction between the heat generated from the used fuel, the flow of water and vapour in the seals, and the deformation and pressure in the seals due to the swelling potential of the bentonite were developed using experimental data from small-scale laboratory testsFootnote 26 Footnote 36 Footnote 37 Footnote 44 Footnote 46.
      • The model was used to predict the behaviour of the seals and their interaction with the surrounding granite during heater experiments performed at the KamaishiFootnote 31 Footnote 32 Footnote 33 Footnote 38 Footnote 45and GrimselFootnote 29 Footnote 30 URLs.
      • The model was used to assess implications on the safety features of a hypothetical repository for used fuel in the Canadian Shield Footnote 27 Footnote 42. It was found that swelling induced additional pressure on the container, and therefore its design must take this extra loading into account. Secondly, the heat from the used fuel would be transferred through the seal, into the rock. The higher temperature can increase the extent of the rock damage zone that was induced by excavation. The damage zone could constitute preferential pathways for radionuclide transport, and therefore must be taken into account in the design and safety assessment of the repository.

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    3. Research activities from 2009-present

    During this period, the CNSC:

    • Published guidance document G-320Footnote 49 that introduces the concept of a safety case to demonstrate the long term safety of radioactive waste management.
    • Performed research on sedimentary rock

    Guidance document G-320Footnote 51 recommends that the safety of waste management facilities be demonstrated by a “safety case”, a documented set of arguments that provide reasonable assurance that human health and the environment would be protected. Central to the safety case is a systematic and quantitative analysis of the future impact of the facility on human health and the environment. That analysis is called a safety assessment, which must be supported by additional arguments such as natural analogues (examples in nature of materials or processes which are similar to the ones around or caused by a geological repository), robustness (the resilience to future perturbations such as earthquakes, etc.) and other multiple lines of reasoning and evidence.

    The research on sedimentary rocks over this period is summarized as follows:

    • ExperimentalFootnote 57 Footnote 60 and theoreticalFootnote 52 research on the mechanical behaviour of sedimentary rocks was performed. That mechanical behaviour is time-dependent and is influenced by the layers that formed in that type of rock during the sediment deposition.
    • Using the results of field tests performed at the Mont Terri URL, the extent and characteristics of the excavation damage zone (EDZ) around tunnels were predicted and compared to the field measurements. Although the extent of the EDZ is limited, it can constitute faster pathways for water and gas migrationFootnote 53 Footnote 54. The EDZ must then be considered in the design and safety assessment of a deep geological repository Footnote 65.
    • Gas generated in a deep geological repository can potentially migrate and transport radionuclides to the surface. Mathematical models of gas migration in sedimentary rocks were developed using experimental data from surface laboratories and URLs Footnote 53 Footnote 55 Footnote 61 Footnote 63 Footnote 64. The models, validated with experimental data, show that if the gas pressure is smaller than the existing state of stress around a geological repository, gas migration would be confined in the host rock in the vicinity of the repository. This would be the case for the DGR proposed by the OPGFootnote 61.
    • Sedimentary rocks of the Michigan Basin have been submitted to nine glacial cycles during the past million years. The maximum thickness of the ice cap could attain 3-5 km, resulting in an enormous stress on the surface (30 to 50 MPa, equivalent to the pressure under a water depth of 3 to 5 km). Mathematical modelling of the effects of past and future glaciationFootnote 56 Footnote 58 Footnote 59 Footnote 62 Footnote 66 Footnote 67, validated with field data indicates that:
      • Despite nine glacial cycles, the groundwater at more than 500 m depth at the Bruce site has remained stagnant. The chemistry of that groundwater shows irrefutable evidence that groundwater at that depth is millions of years old and had not mixed with shallower groundwater or surface water.
      • Damage of the rock due to the ice pressure is restricted to a few hundred of metres from the surface.
      • If a future glaciation cycle occurs on the site of a deep geological repository, modelling shows that radionuclides will be contained in the vicinity of the host rock. Only in the improbable case of severe failure of the shafts, would radionuclides reach the shallower groundwater.
    • Natural analogues (e.g. ancient uranium ore bodies that formed billions of years ago, and have remained stable since that time) for nuclear waste disposal provide information over geological timescales and spatial scales. Natural analogues for nuclear waste were reviewedFootnote 68, and are deemed necessary to complement experiments carried out over months or years, and to validate numerical safety assessment models.

    Effect of glaciation on sedimentary rocks. Glaciation imposes an enormous load on the rock formation, generating very high pressures in the rock (red zones in a) approximately equivalent to a 3-km column of water. However, the rock at depths of more than 500 m is practically impermeable and would contain the movement of radionuclides to very small zones (red zones in b).

    Graphic showing the pressure distribution

    a) Pressure distribution

    Graphic showing a tracer movement

    b) Tracer movement

    The SEALEX experimental program at the Tournemire URL, France. The CNSC and France’s Institute for Radiation Protection and Nuclear Safety (IRSN) collaborate on experimental and theoretical studies on the long-term performance of bentonite seals.

    Photo of a test set up

    a) Test setup
     

    Photo of a Precompacted bentonite seal blocks emplaced in horizontal borehole

    b) Precompacted bentonite seal blocks emplaced in horizontal borehole

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    Reference list

    References refer to research completed by the CNSC. There is other research completed and ongoing domestically and internationally. Not all references cited are available in full text online. Please contact the CNSC to CNSC to obtain copies of available articles.

    Footnote 1

    D.J. Bottomley, The Geochemical Immobilization of Uranium in a Spent Fuel Repository in the Canadian Shield: Evidence from Natural Analogue Investigations (Atomic Energy Control Board Report, 1996, INFO-0641).

    Return to footnote 1 referrer

    Footnote 2

    D.J Bottomley, An Overview of Potential Isotopic Techniques for Dating Groundwaters in Crystalline Rocks (Atomic Energy Control Board Report, 1996, INFO-0630).

    Return to footnote 2 referrer

    Footnote 3

    D.J. Bottomley, A Review of Theories on the Origins of Saline Waters and Brines in the Canadian Precambrian Shield (Atomic Energy Control Board Report, 1996, INFO-0631).

    Return to footnote 3 referrer

    Footnote 4

    D.J. Bottomley,“The Paleohydrogeology of Plutons on the Canadian Precambrian Shield: Evidence from the Isotopic Composition of Fracture Calcites”, Paleohydrogeological Methods and Their Applications (Proceedings of a Nuclear Energy Agency workshop / Organization for Economic Co-operation and Development, Paris, 1992).

    Return to footnote 4 referrer

    Footnote 5

    P. Flavelle, Perspectives of the Scale of the Canadian Nuclear Fuel Waste Disposal Concept (Atomic Energy Control Board Report, 1996-a, INFO-0635).

    Return to footnote 5 referrer

    Footnote 6

    P. Flavelle, Reference Used Fuel for the Canadian Nuclear Fuel Waste Disposal Concept (Atomic Energy Control Board Report, 1996-b, INFO-0633).

    Return to footnote 6 referrer

    Footnote 7

    P. Flavelle, Source Term for the Bounding Assessment of the Canadian Nuclear Fuel Wastes Disposal Concept (Atomic Energy Control Board Report, 1996-c, INFO-0634).

    Return to footnote 7 referrer

    Footnote 8

    P. Flavelle, Regulatory Perspectives of Concept Assessment (Atomic Energy Control Board Report, 1987, INFO-0256).

    Return to footnote 8 referrer

    Footnote 9

    S. Lei and D. Metcalfe, Impacts of Disturbed Rock Zones and Backfill Material on Groundwater Flow and Radionuclide Transport Through a Generic HLW Repository (Atomic Energy Control Board, 1996, INFO-0636).

    Return to footnote 9 referrer

    Footnote 10

    D. Metcalfe, Regional-Scale Groundwater Flow Modelling of Generic High Level Waste Disposal Sites (Atomic Energy Control Board, 1996, INFO-0632).

    Return to footnote 10 referrer

    Footnote 11

    T.S. Nguyen and A.P.S. Selvadurai, “Coupled thermal–hydraulic–mechanical processes in a cylindrical cavity in rock” (invited lecture, NUMOG VI, Proceedings of the International Symposium on Numerical Models in Geomechanics, G.N. Pande and S. Pietruszczak, Eds., Montréal, Canada, A.A. Balkema, The Netherlands, 1997), pp. 315-324.

    Return to footnote 11 referrer

    Footnote 12

    A.P.S. Selvadurai and T.S. Nguyen, “Mechanics and fluid transport in a degradable discontinuity” (Proceedings of the Workshop on Computational Methods in Engineering Geology, R. Pusch and R. Adey, Eds., Lund, Sweden, 1996) pp. 160-169.

    Return to footnote 12 referrer

    Footnote 13

    T.S. Nguyen, A.P.S. Selvadurai and P. Flavelle, “Modelling of Thermal-Hydrological-Mechanical Processes in a Discrete Joint” (Engineering Mechanics, Y.K. Lin and T.C. Su, Eds., Proceedings of the 11th Conference, Fort Lauderdale, FL, ASCE Publications,1996) Vol. 1, pp. 60-63.

    Return to footnote 13 referrer

    Footnote 14

    A.P.S. Selvadurai and T.S. Nguyen, “Scoping Analyses of the Coupled Thermal-Hydrological-Mechanical Behaviour of the Rock Mass Aaround a Nuclear Fuel Waste Repository” (Engineering Geology, 1996) Vol. 47, pp. 379-400.

    Return to footnote 14 referrer

    Footnote 15

    T.S. Nguyen and A.P.S. Selvadurai, “Modelling of Thermal Consolidation of Sparsely Fractured Rock in the Context of Nuclear Waste Management” (Mechanics of PoroelasticMedia, A.P.S. Selvadurai, Ed., Proceedings of the Specialty Conference on Recent Developments in Poroelasticity, Kluwer Academic Publishers, The Netherlands, 1996) pp. 159-180.

    Return to footnote 15 referrer

    Footnote 16

    T.S. Nguyen and A.P.S. Selvadurai, “Coupled Thermal-Mechanical-Hydrological Behaviour of Sparsely Fractured Rock: Implications for Nuclear Fuel Waste Disposal” (International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, 1995), Vol. 32, pp. 465-479.

    Return to footnote 16 referrer

    Footnote 17

    A.P.S. Selvadurai and T.S. Nguyen, “Computational Modelling of Isothermal Consolidation of Fractured Porous Media” (Computers and Geotechnics, 1995) Vol. 17, pp. 39-73.

    Return to footnote 17 referrer

    Footnote 18

    T.S. Nguyen and A.P.S. Selvadurai, “Thermo-Poroelastic Response of a Fractured Geological Medium” (IACMAG ‛94, Proceedings of the 8th International Conference of the International Association of Computer Methods and Advances in Geomechanics, H.J. Siriwardane and M.M. Zaman, Eds., Morgantown, W.Va., A.A. Balkema, The Netherlands, 1994) Vol. II, pp. 1615-1620.

    Return to footnote 18 referrer

    Footnote 19

    A.P.S. Selvadurai and T.S. Nguyen, “Coupled Thermal-Hydrological-Mechanical Processes in Geological Media” (Proceedings International Conference on Computational Methods in Structural and Geotechnical Engineering, P.K.K. Lee, Ed., Hong Kong, 1994) pp. 1528-1533.

    Return to footnote 19 referrer

    Footnote 20

    A.P.S. Selvadurai and T.S. Nguyen, “Finite Element Modelling of Consolidation of Fractured Porous Media” (Proceedings of the 46th Canadian Geotechnical Conference, Saskatoon, Saskatchewan, 1993), pp. 361-370.

    Return to footnote 20 referrer

    Footnote 21

    T.S. Nguyen, V. Poliscuk and A.P.S. Selvadurai, “Effects of Glaciation on a Nuclear Fuel Waste Repository” (Proceedings of the 46th Canadian Geotechnical Conference, Saskatoon, Saskatchewan, 1993), pp. 79-88.

    Return to footnote 21 referrer

    Footnote 22

    T.S. Nguyen and V. Poliscuk, “Seismic Effects on a Nuclear Fuel Waste Repository” (45th Canadian Geotechnical Conference, 1992).

    Return to footnote 22 referrer

    Footnote 23

    Atomic Energy Control Board (AECB), AECB Staff Response to the Environmental Impact Statement on the Concept of Canada's Nuclear Fuel Waste (Atomic Energy Control Board Report, 1995, INFO-0585-1).

    Return to footnote 23 referrer

    Footnote 24

    D.J. Bottomley, L.H. Chan, A. Katz, A. Starinsky and I.D. Clark, Lithium Isotope Geochemistry and Origin of Canadian Shield Brines (Groundwater, 2003) Vol. 41, No. 6, pp. 847-856.

    Return to footnote 24 referrer

    Footnote 25

    D.J. Bottomley, I.D. Clark, N. Battye and T. Kotzer, “Geochemical and Isotopic Evidence for a Genetic Link Between Canadian Shield Brines, Dolomitization in the Western Canada Sedimentary Basin, and Devonian Calcium-Chloridic Seawater” (Canadian Journal of Earth Sciences, 2005), Vol 42, pp. 2059-2071.

    Return to footnote 25 referrer

    Footnote 26

    M. Chijimatsu, T.S. Nguyen et al., “Model Development and Calibration for the Coupled Thermal, Hydraulic and Mechanical Phenomena of the Bentonite” (Environmental Geology, 2009), Vol 57, No. 6.

    Return to footnote 26 referrer

    Footnote 27

    T.S. Nguyen et al.,“A Case Study on the Influence of THM Coupling on the Near Field Safety of a Spent Fuel Repository in Sparsely Fractured Granite” (Environmental Geology, 2009) Vol. 57, No. 6.

    Return to footnote 27 referrer

    Footnote 28

    J. Rutqvist, T.S. Nguyen et al., “Modeling of Damage, Permeability Changes and Pressure Responses During Excavation of the TSX Tunnel in Granitic Rock at URL, Canada” (Environmental Geology, 2009) Vol. 57, No. 6.

    Return to footnote 28 referrer

    Footnote 29

    T.S. Nguyen, A.P.S. Selvadurai and G. Armand, “Modelling the FEBEX THM Experiment Using a State Surface Approach” (International Journal of Rock Mechanics and Mining Sciences, 2005) Vol. 42, pp. 639-651.

    Return to footnote 29 referrer

    Footnote 30

    E.E. Alonso, T.S. Nguyen et al., “The Febex Benchmark Test: Case Definition and Comparison of Modelling Approaches” (International Journal of Rock Mechanics and Mining Sciences, 2005) Vol. 42, pp. 611-638.

    Return to footnote 30 referrer

    Footnote 31

    M. Chijimatsu, T.S. Nguyen et al., “Numerical Study of the THM Effects on the Near-Field Safety of a Hypothetical Nuclear Waste Repository – BMT1 of the DECOVALEX III Project. Part 1: Conceptualization and Characterization of the Problems and Summary of Results” (International Journal of Rock Mechanics and Mining Sciences, 2005) Vol. 42. pp. 720-730.

    Return to footnote 31 referrer

    Footnote 32

    A. Millard, T.S. Nguyen et al., “Numerical Study of the THM Effects on the Near-Field Safety of a Hypothetical Nuclear Waste Repository – BMT1 of the DECOVALEX III Project. Part 2: Effects of THM Coupling in Continuous and Homogeneous Rocks” (International Journal of Rock Mechanics and Mining Sciences, 2005) Vol. 42, pp. 731-744.

    Return to footnote 32 referrer

    Footnote 33

    J. Rutqvist, T.S. Nguyen et al., “A Numerical Study of the THM Effects on the Near-Field Safety of a Hypothetical Nuclear Waste Repository – BMT1 of the DECOVALEX III Project. Part 3: Effects of THM Coupling in Sparsely Fractured Rocks” (International Journal of Rock Mechanics and Mining Sciences, 2005) Vol. 42, pp. 745-755.

    Return to footnote 33 referrer

    Footnote 34

    A.P.S. Selvadurai, M.J. Boulon and T.S. Nguyen, “The Permeability of an Intact Granite (Pure and Applied Geophysics,2005) Vol. 162, pp. 373-407.

    Return to footnote 34 referrer

    Footnote 35

    T.S. Nguyen et al., “Hydro-Mechanical Response of a Fractured Granitic Rock Mass to Excavation of a Test Pit – the Kamaishi Mine Experiment in Japan” (International Journal of Rock Mechanics and Mining Sciences, 2001) Vol. 38, pp. 79-94.

    Return to footnote 35 referrer

    Footnote 36

    L. Borgesson, T.S. Nguyen et al., “Thermo-Hydro-Mechanical Characterization of a Bentonite-Based Buffer Material by Laboratory Tests and Numerical Analyses” (International Journal of Rock Mechanics and Mining Sciences, 2001), Vol. 38, No. 1, pp. 95-104.

    Return to footnote 36 referrer

    Footnote 37

    J. Rutqvist, T.S. Nguyen et al., “Thermohydromechanics of Partially Saturated Geological Media: Governing Equations and Formulation of Four Finite Element Models” (International Journal of Rock Mechanics and Mining Sciences, 2001), Vol. 38, No. 1, pp. 105-128.

    Return to footnote 37 referrer

    Footnote 38

    J. Rutqvist, T.S. Nguyen et al., “Coupled Thermo-Hydro-Mechanical Analysis of a Heater Test in Fractured Rock and Bentonite at Kamaishi Mine – Comparison of Field Results to Predictions of Four Finite Element Codes” (International Journal of Rock Mechanics and Mining Sciences, 2001), Vol. 38, No. 1, 129-142.

    Return to footnote 38 referrer

    Footnote 39

    A.P.S Selvadurai and T.S. Nguyen, “Mechanics and Fluid Transport in a Degradable Discontinuity” (Engineering Geology, 1999) Vol. 53, pp. 243-249.

    Return to footnote 39 referrer

    Footnote 40

    T.S. Nguyen. “Damage of Lac du Bonnet Granite in Triaxial Tests” (Canadian Geotechnical Conference, Ottawa, 2007).

    Return to footnote 40 referrer

    Footnote 41

    T.S. Nguyen, “Excavation Damage and Pore Pressure Evolutions Around a Test Tunnel in Granite” (Canadian Geotechnical Conference, Ottawa, 2007).

    Return to footnote 41 referrer

    Footnote 42

    T.S. Nguyen, L. Borgesson, M. Chijimatsu, T. Fujita, J. Hernelind, P. Jussila, J, Rutqvist and L. Jing, “Influence of Coupled THM Phenomena on the Safety of a Spent Fuel Repository: a Near Field Study” (Proceedings of the GEOPROC conference, Hohai University, Nanjing, 2006).

    Return to footnote 42 referrer

    Footnote 43

    T.S. Nguyen, T. Chan and M. Jensen, “Le projet DECOVALEX: couplage thermo-hydro-mécanique et évacuation du combustible usé” (Canadian Geotechnical Conference, Quebec City, 2004).

    Return to footnote 43 referrer

    Footnote 44

    T.S. Nguyen, A.P.S. Selvadurai and G. Armand, “Thermo-Hydro-Mechanical Behaviour of Unsaturated Bentonite” (NUMOG IX, Proceedings of the 9th International Symposium on Numerical Models in Geomechanics, G.N. Pande and S. Pietruszczak, Eds., Ottawa, ON, Canada, 2004), pp. 319-326.

    Return to footnote 44 referrer

    Footnote 45

    T.S. Nguyen, A.P.S. Selvadurai and G. Armand, “Computational Predictions of the Buffer Response in an In-Situ Heater Test at the Grimsel Site” (Proceedings of the 55th Canadian Geotechnical Conference, Winnipeg, R.M. Kenyon, Ed., 2005) pp. 595-601.

    Return to footnote 45 referrer

    Footnote 46

    T.S. Nguyen, A.P.S. Selvadurai and G. Armand, “Thermo-Poro-Elastic Modelling of Buffer Materials Considered for Nuclear Fuel Waste Disposal Endeavours” (Proceedings of the 55th Canadian Geotechnical Conference, Winnipeg, R.M. Kenyon, Ed., 2003) pp. 602-610.

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    Footnote 47

    A.P.S. Selvadurai, T.S. Nguyen and G. Armand, “Computational Predictions of the Rock Mass Response in an In-Situ Heater Test for Nuclear Waste Disposal” (Proceedings of the 55th Canadian Geotechnical Conference, Winnipeg, R.M. Kenyon, Ed., 2003) pp. 611-618.

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    Footnote 48

    A.P.S. Selvadurai, T.S. Nguyen and G. Armand, “Thermo-Poro-Elastic Response of an Embedded Inclusion” (invited lecture, Proceedings of the 6th Asia Pacific Conference in Computational Mechanics, Sydney, Australia, S. Valliappan and N. Khalili, Eds., Elsevier, The Netherlands, 2001) pp. 837-852.

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    Footnote 49

    A.P.S. Selvadurai, T.S. Nguyen and G. Armand, “Computational and Analytical Estimates for Thermo-Hydro-Mechanical (THM) Behaviour of a Fluid Saturated Porous Medium” (Proceedings of the 6th International Workshop on Key Issues in Waste Isolation Research, ENPC, Paris, 2001) pp. 543-591.

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    Footnote 50

    A.P.S. Selvadurai, M.J. Boulon and T.S. Nguyen, “Permeability of an Intact Granite” (Proceedings of the 6th International Workshop on Key Issues in Waste Isolation Research, ENPC, Paris, 2001) pp. 103-152.

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    Footnote 51

    Canadian Nuclear Safety Commission (CNSC), Regulatory Guidance G-320: Assessing the Long Term Safety of Radioactive Waste Management, 2006.

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    Footnote 52

    T.S. Nguyen and D.A. Le, “Development of a Constitutive Model for a Bedded Argillaceous Rock from Triaxial and True Triaxial Tests” (Canadian Geotechnical Journal, 2014) d.o.i. 10.1139/cgj-2013-0323.

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    Footnote 53

    T.S. Nguyen and D.A. Le, “Simultaneous Gas and Water Flow in a Bedded Argillaceous Rock” (Canadian Geotechnical Journal, 2014) d.o.i. 10.1139/cgj-2013-0457.

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    Footnote 54

    D.A. Le and T.S. Nguyen, “Hydromechanical Response of a Bedded Argillaceous Rock Formation to Excavation and Water Injection” (Canadian Geotechnical Journal 2014) d.o.i 10.1139/cgj-2013-0324.

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    Footnote 55

    M. Fall, O. Nasir and T.S. Nguyen. “A Coupled Hydro-Mechanical Model for Simulation of Gas Migration in Host Sedimentary Rocks for Nuclear Waste Repositories” (Engineering Geology,2014), Vol. 176, pp. 24-44.

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    Footnote 56

    M. Fall, O. Nasir, T.S. Nguyen and E. Evgin, “Modeling of the Thermo-Hydro-Mechanical-Chemical Response of Ontario Sedimentary Rocks to Future Glaciations” (Canadian Geotechnical Journal, 2014), d.o.i. 10.1139/cgj-2013-0016.

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    Footnote 57

    H. Abdi, D. Labrie, T.S. Nguyen, J.D. Barnichon, G. Su, E. Evgin, R. Simon and M. Fall “Laboratory Investigation on the Mechanical Behaviour of Tournemire Argillite”, Canadian Geotechnical Journal, 2014), d.o.i. 10.1139/cgj-2013-0122.

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    Footnote 58

    Nasir, O., Fall, M., Nguyen, S., Evgin, E., “Modeling of the Thermo-Hydro-Mechanical-Chemical Response of Sedimentary Rocks of Ontario to Past Glaciations” (International Journal of Rock Mechanics and Mining Sciences, 2013) Vol. 64, pp.160-174.

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    Footnote 59

    O.Nasir, M. Fall, T.S. Nguyen and E. Evgin, “Modeling of Hydro-Mechanical Response of Sedimentary Rocks of Southern Ontario to Past Glaciation” (Engineering Geology, 2011), Vol. 123, No. 4, pp. 288-301.

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    Footnote 60

    H. Abdi, D. Labrie, T.S. Nguyen, J.D. Barnichon, G. Su , E, Evgin, R. Simon and M. Fall, “Laboratory Investigation and Preliminary Modelling of the Mechanical Behaviour of Transversely Isotropic Tournemire Shale“ (Proceedings of Canadian Geotechnical Conference – Geomanitoba 2012, Winnipeg, Manitoba, 2012).

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    Footnote 61

    M. Fall, O. Nasir and T.S. Nguyen, “Coupled Hydro-Mechanical Modelling of Gas Migration in Ontario’s Sedimentary Rocks, Potential Host Rocks for Nuclear Waste Repositories“ (Proceedings of Canadian Geotechnical Conference – Geomanitoba 2012,   Winnipeg, Manitoba, 2012).

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    Footnote 62

    O. Nasir, M. Fall, T.S. Nguyen and E. Evgin, “Effects of Past Glaciations on the Hydrogeology of Michigan Basin” (Proceedings of the second International Conference on Computational Geomechanics, ComGeo II, Croatia, 27-29 April, 2011).

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    Footnote 63

    T.S. Nguyen, S. Grant, M. Fall and E. Evgin, “Simulation of a Gas Injection Test in a Layered Argillaceous Rock“ (Proceedings of the second International Conference on Computational Geomechanics, ComGeo II, Croatia, 27-29 April, 2011).

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    Footnote 64

    T.S. Nguyen T.S., M. Fall and O. Nasir, “Simultaneous Flow of Gas and Water in a Damage-Susceptible Argillaceous Rock“ (invited presentation, American Geophysical Union (AGU) Fall meeting, San Francisco, December 5-9, 2011 – PAPER NS11A-1449).

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    Footnote 65

    H. Abdi, T.S. Nguyen, E. Evgin, M. Fall and S. Grant, “Coupled hydro-mechanical analysis of excavation damaged zone around an underground opening in sedimentary rock” Comsol Conference 2010, Boston, 2010.

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    Footnote 66

    S. Nguyen, O. Nasir, M. Fall, E. Evgin, “Effects of Past Glaciations on Sedimentary Rocks in Ontario” (International conference on Clays in Natural & Engineered Barriers for Radioactive Waste Confinement, Nantes, France, 2009).

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    Footnote 67

    O. Nasir, M. Fall, T.S. Nguyen and E. Evgin, “Hydro-Mechanical Response of Sedimentary Rocks of Southern Ontario to Past Glaciations” COMSOL Conference 2009, Boston, 2009.

    Return to footnote 67 referrer

    Footnote 68

    M. Fayek and J.L. Brown, “Natural and Anthropogenic Analogues for High-Level Nuclear Waste Disposal Repositories: A Review” (Canadian Nuclear Safety Commission, 2015, RSP-310. 59p.)

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