{"id":7087,"date":"2024-11-12T08:50:15","date_gmt":"2024-11-12T07:50:15","guid":{"rendered":"https:\/\/ingenius.ecoledesponts.fr\/?p=7087"},"modified":"2024-11-12T16:41:00","modified_gmt":"2024-11-12T15:41:00","slug":"underground-radioactive-waste-storage-contributions-from-geomechanics","status":"publish","type":"post","link":"https:\/\/ingenius.ecoledesponts.fr\/en\/articles\/underground-radioactive-waste-storage-contributions-from-geomechanics\/","title":{"rendered":"Underground radioactive waste storage: contributions from geomechanics"},"content":{"rendered":"\n\n\n
\"\"
Underground research laboratory, Bure, 2019. Cr\u00e9dit : Damien Valente \/ Terra<\/figcaption><\/figure>\n\n\n\n

Annual primary energy consumption in France can be broken down as follows: 35% nuclear, 32% oil, 14% natural gas, 17% renewables, and 2% coal. Due to the significant contribution of nuclear energy, in addition to renewable sources, 52% of the energy consumed in France is from low-carbon sources, i.e. nuclear and renewables. This places France in fifth position worldwide, behind Sweden (74%), Norway (72%), Finland (62%), and Switzerland (57%<\/a>) in terms of the proportion of low-carbon energies in the energy mix.<\/p>\n\n\n\n

\"\"
Cr\u00e9dit : Ghabezloo<\/figcaption><\/figure>\n\n\n\n

This privilege however comes with an important quantity of nuclear waste, approximately 1.79 million cubic meters to date, which must be managed. Most of the radioactivity of this waste, approximately 95%, is concentrated in a minute proportion, 0.2%, i.e. a volume of 4,420 cubic meters (2022 data) of so-called high-level <\/em>waste.<\/em> So-called intermediate-level<\/em> long-lived <\/em>waste takes up 2.9% of the total volume of waste, equivalent to 39,600 cubic meters. These two categories of waste require special treatment given their high level of activity or their long life span.1<\/a><\/sup><\/p>\n\n\n\n

\"\"
Cr\u00e9dit : Ghabezloo. Source :National Inventory of radioactive materials and waste<\/a>.<\/figcaption><\/figure>\n\n\n\n

Geological storage: a sustainable solution<\/h2>\n\n\n\n

The proposed solution in France, as in many other countries, is geological storage. The principle is to contain and isolate waste, far from the biosphere underground, using geological barriers, i.e. host rock, and engineered barriers (isolation of waste with layers of glass, steel, concrete, and clay materials). In France, Andra (Agence Nationale pour la gestion des D\u00e9chets RAdioactifs<\/em>, the country\u2019s national radioactive waste management agency) is tasked with implementing this solution. In the framework of Cig\u00e9o (Centre Industriel de stockage G\u00c9Ologique<\/em>, industrial geological storage center) project, located in Meuse\/Haute-Marne, the candidate host rock is a clay rock, called Callovo-Oxfordian claystone. This rock was chosen in particular due to its geological stability, its ability to contain radionuclides 2<\/a><\/sup>, and its very low permeability. The depth of the layer, approximately 500 meters, combined with its thickness of approximately 150 meters and its extremely low permeability can guarantee effective isolation of waste for several centuries. The planned storage system consists of a network of tunnels connected to the surface by access shafts. A set of micro-tunnels is planned in each tunnel where high-level radioactive waste will be stored. In addition, larger-diameter micro-tunnels are planned for intermediate-level long-lived waste. The challenges of the design and construction of such a system are in some ways similar to the issues facing major civil engineering projects such as deep tunnels, including the design of tunnels and tunnel support systems to prevent failure and to limit deformations to acceptable values. The exothermic nature of radioactive waste and the very low permeability of the rock provide additional challenges. Nevertheless, the major difference is in terms of project life span: whereas radioactive waste storage spans several centuries, civil engineering projects last a few decades. To demonstrate the feasibility of geological storage and study the behavior of the candidate host rock, an underground research laboratory was built by Andra, starting back in the 2000s, near the location of a future storage project. This laboratory provides the opportunity to test different tunnel excavation methods and support systems, as well as to conduct in-situ tests and experiments.<\/p>\n\n\n\n

Geomechanical aspects<\/h2>\n\n\n\n

Geomechanical aspects play a significant role in the phenomena at play in a geological storage system in clay rocks. For the duration of a storage site\u2019s life span, from tunnel construction to long-term exothermic waste storage, the host rock is subjected to a range of mechanical, hydraulic, and thermal loadings. The porous nature of the clay rocks, their extremely low permeabilities, and the presence of clayey minerals make their response highly dependent on multiphysics couplings. Accordingly, tunnel excavation causes deformations of the rock, and local variations in the pore water pressure acting in its microstructure, generating time-dependent water flows and deformations. The heat emitted by radioactive waste and its progressive diffusion create temperature gradients in the rock, causing instantaneous thermal expansion of the rock and variations in the pore water pressure. These in turn result in water flows and deformations. In-depth understanding of these phenomena is essential for the design of the geological storage system.<\/p>\n\n\n\n

Development of design tools<\/h2>\n\n\n\n

The design of radioactive waste geological storage infrastructure requires numerical simulations at the scale of the structure to predict the system\u2019s performances during the different stages of its life. These simulations require constitutive laws tailored to different materials, under conditions representative of the modelled storage situation. Identification of these constitutive laws and assessment of their parameters are based mainly on the laboratory\u2019s experimental studies. The low permeability of the rock and the potential for expansion of clay minerals make experiments relatively complex and potentially long. Experimental results must be analyzed and interpreted in conjunction with theoretical models and, in some cases using numerical simulations. The efficiency of these approaches is verified via comparison with in-situ measurements and observations made in the underground laboratory.<\/p>\n\n\n\n

Research at the Navier laboratory<\/h2>\n\n\n\n

The Navier laboratory conducts research activities related to the aforementioned challenges, and in collaboration with different agencies and organizations tasked with radioactive waste management. Many of them are conducted at the laboratory to explore the behavior of different storage system materials under mechanical, hydraulic, and thermal loads, to develop constitutive laws. Integration of these equations into numerical simulation tools enables the analysis and prediction of storage system performances during the different stages of its life. Analysis of data from in-situ instrumentation, measurements and experiments in Andra’s underground research laboratory provides a complementary view and demonstrates the system\u2019s response under conditions closer to actual storage conditions. Advanced numerical modelling tools are deployed in the analysis of this data. The complementarity of all these approaches, in-lab studies, theoretical developments, numerical simulations, and in-situ experiments and measurements offers a unique opportunity for multidisciplinary research in the service of a major project.<\/p>\n\n\n\n

\"\"
Triaxial cell system used to study the thermo-hydro-mechanical behavior of geomaterials. Credit: Jean-Claude Moschetti<\/em><\/figcaption><\/figure>\n\n\n
  1. So-called \u201clong-lived\u201d waste has a half-life of over 31 years and remains active for more than 300 years or even thousands of years in the case of the most radioactive (source www.edf.fr) \u21a9\ufe0e<\/a><\/li>
  2. Radioactive atom capable of transforming into another \u21a9\ufe0e<\/a><\/li><\/ol>","protected":false},"excerpt":{"rendered":"

    Annual primary energy consumption in France can be broken down as follows: 35% nuclear, 32% oil, 14% natural gas, 17% […]<\/p>\n","protected":false},"author":9,"featured_media":7173,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_related_content_post":[],"_related_content_subject":[937],"_related_content_author":[5341],"_related_content_category":[1720,1716],"_related_content_folder":[6913],"_excerpt":"In France, approximately 52% of energy consumed is from low-carbon sources, mainly stemming from nuclear energy and renewables, placing the country among the world leaders in this field. However, this position comes with major challenges in terms of managing radioactive waste from nuclear activities. The country is planning on geological storage to secure this waste in the long term, a solution involving complex technical and geomechanical challenges, requiring in-depth research in which the Navier Laboratory has been actively participating for the past two decades.","_duration":4,"_manual_duration":false,"footnotes":"[{\"content\":\"So-called \u201clong-lived\u201d waste has a half-life of over 31 years and remains active for more than 300 years or even thousands of years in the case of the most radioactive (source www.edf.fr)\",\"id\":\"47be8115-121e-432e-9f99-9623f5f7fd0b\"},{\"content\":\"Radioactive atom capable of transforming into another\",\"id\":\"84219bd1-afaa-4cc1-a208-e000ab1ae935\"}]"},"article-types":[13,27],"class_list":["post-7087","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","article-types-article","article-types-folder"],"has_blocks":true,"block_data":[{"blockName":"enpc\/excerpt","attrs":{"lock":[],"metadata":[],"className":"","style":""},"innerBlocks":[],"innerHTML":"","innerContent":[],"rendered":""},{"blockName":"core\/image","attrs":{"id":7173,"sizeSlug":"large","linkDestination":"none","align":"wide","blob":"","url":"https:\/\/ingenius.ecoledesponts.fr\/wp-content\/uploads\/2024\/11\/DV010961_Damien_Valente_Terra-1024x683.jpg","alt":"","caption":"Underground research laboratory, Bure, 2019. Cr\u00e9dit : Damien Valente \/ Terra","lightbox":[],"title":"","href":"","rel":"","linkClass":"","width":"","height":"","aspectRatio":"","scale":"","linkTarget":"","lock":[],"metadata":[],"className":"wp-block-image alignwide size-large","style":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    \"\"
    Underground research laboratory, Bure, 2019. Cr\u00e9dit : Damien Valente \/ Terra<\/figcaption><\/figure>\n","innerContent":["\n
    \"\"
    Underground research laboratory, Bure, 2019. Cr\u00e9dit : Damien Valente \/ Terra<\/figcaption><\/figure>\n"],"rendered":"\n
    \"\"
    Underground research laboratory, Bure, 2019. Cr\u00e9dit : Damien Valente \/ Terra<\/figcaption><\/figure>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"Annual primary energy consumption in France can be broken down as follows: 35% nuclear, 32% oil, 14% natural gas, 17% renewables, and 2% coal. Due to the significant contribution of nuclear energy, in addition to renewable sources, 52% of the energy consumed in France is from low-carbon sources, i.e. nuclear and renewables. This places France in fifth position worldwide, behind Sweden (74%), Norway (72%), Finland (62%), and Switzerland (57%) in terms of the proportion of low-carbon energies in the energy mix.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Annual primary energy consumption in France can be broken down as follows: 35% nuclear, 32% oil, 14% natural gas, 17% renewables, and 2% coal. Due to the significant contribution of nuclear energy, in addition to renewable sources, 52% of the energy consumed in France is from low-carbon sources, i.e. nuclear and renewables. This places France in fifth position worldwide, behind Sweden (74%), Norway (72%), Finland (62%), and Switzerland (57%<\/a>) in terms of the proportion of low-carbon energies in the energy mix.<\/p>\n","innerContent":["\n

    Annual primary energy consumption in France can be broken down as follows: 35% nuclear, 32% oil, 14% natural gas, 17% renewables, and 2% coal. Due to the significant contribution of nuclear energy, in addition to renewable sources, 52% of the energy consumed in France is from low-carbon sources, i.e. nuclear and renewables. This places France in fifth position worldwide, behind Sweden (74%), Norway (72%), Finland (62%), and Switzerland (57%<\/a>) in terms of the proportion of low-carbon energies in the energy mix.<\/p>\n"],"rendered":"\n

    Annual primary energy consumption in France can be broken down as follows: 35% nuclear, 32% oil, 14% natural gas, 17% renewables, and 2% coal. Due to the significant contribution of nuclear energy, in addition to renewable sources, 52% of the energy consumed in France is from low-carbon sources, i.e. nuclear and renewables. This places France in fifth position worldwide, behind Sweden (74%), Norway (72%), Finland (62%), and Switzerland (57%<\/a>) in terms of the proportion of low-carbon energies in the energy mix.<\/p>\n"},{"blockName":"core\/image","attrs":{"id":7220,"width":"512px","height":"auto","sizeSlug":"large","linkDestination":"none","align":"center","blob":"","url":"https:\/\/ingenius.ecoledesponts.fr\/wp-content\/uploads\/2024\/11\/Energ-consumption-France-1024x747.png","alt":"","caption":"Cr\u00e9dit : Ghabezloo","lightbox":[],"title":"","href":"","rel":"","linkClass":"","aspectRatio":"","scale":"","linkTarget":"","lock":[],"metadata":[],"className":"wp-block-image aligncenter size-large is-resized","style":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    \"\"
    Cr\u00e9dit : Ghabezloo<\/figcaption><\/figure>\n","innerContent":["\n
    \"\"
    Cr\u00e9dit : Ghabezloo<\/figcaption><\/figure>\n"],"rendered":"\n
    \"\"
    Cr\u00e9dit : Ghabezloo<\/figcaption><\/figure>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"This privilege however comes with an important quantity of nuclear waste, approximately 1.79 million cubic meters to date, which must be managed. Most of the radioactivity of this waste, approximately 95%, is concentrated in a minute proportion, 0.2%, i.e. a volume of 4,420 cubic meters (2022 data) of so-called high-level waste. So-called intermediate-level long-lived waste takes up 2.9% of the total volume of waste, equivalent to 39,600 cubic meters. These two categories of waste require special treatment given their high level of activity or their long life span.1","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    This privilege however comes with an important quantity of nuclear waste, approximately 1.79 million cubic meters to date, which must be managed. Most of the radioactivity of this waste, approximately 95%, is concentrated in a minute proportion, 0.2%, i.e. a volume of 4,420 cubic meters (2022 data) of so-called high-level <\/em>waste.<\/em> So-called intermediate-level<\/em> long-lived <\/em>waste takes up 2.9% of the total volume of waste, equivalent to 39,600 cubic meters. These two categories of waste require special treatment given their high level of activity or their long life span.1<\/a><\/sup><\/p>\n","innerContent":["\n

    This privilege however comes with an important quantity of nuclear waste, approximately 1.79 million cubic meters to date, which must be managed. Most of the radioactivity of this waste, approximately 95%, is concentrated in a minute proportion, 0.2%, i.e. a volume of 4,420 cubic meters (2022 data) of so-called high-level <\/em>waste.<\/em> So-called intermediate-level<\/em> long-lived <\/em>waste takes up 2.9% of the total volume of waste, equivalent to 39,600 cubic meters. These two categories of waste require special treatment given their high level of activity or their long life span.1<\/a><\/sup><\/p>\n"],"rendered":"\n

    This privilege however comes with an important quantity of nuclear waste, approximately 1.79 million cubic meters to date, which must be managed. Most of the radioactivity of this waste, approximately 95%, is concentrated in a minute proportion, 0.2%, i.e. a volume of 4,420 cubic meters (2022 data) of so-called high-level <\/em>waste.<\/em> So-called intermediate-level<\/em> long-lived <\/em>waste takes up 2.9% of the total volume of waste, equivalent to 39,600 cubic meters. These two categories of waste require special treatment given their high level of activity or their long life span.1<\/a><\/sup><\/p>\n"},{"blockName":"core\/image","attrs":{"id":7207,"width":"475px","height":"auto","sizeSlug":"large","linkDestination":"none","align":"center","blob":"","url":"https:\/\/ingenius.ecoledesponts.fr\/wp-content\/uploads\/2024\/11\/Nuclear-waste-France_AM-1024x882.png","alt":"","caption":"Cr\u00e9dit : Ghabezloo. Source :National Inventory of radioactive materials and waste.","lightbox":[],"title":"","href":"","rel":"","linkClass":"","aspectRatio":"","scale":"","linkTarget":"","lock":[],"metadata":[],"className":"wp-block-image aligncenter size-large is-resized","style":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    \"\"
    Cr\u00e9dit : Ghabezloo. Source :National Inventory of radioactive materials and waste<\/a>.<\/figcaption><\/figure>\n","innerContent":["\n
    \"\"
    Cr\u00e9dit : Ghabezloo. Source :National Inventory of radioactive materials and waste<\/a>.<\/figcaption><\/figure>\n"],"rendered":"\n
    \"\"
    Cr\u00e9dit : Ghabezloo. Source :National Inventory of radioactive materials and waste<\/a>.<\/figcaption><\/figure>\n"},{"blockName":"core\/heading","attrs":{"style":{"elements":{"link":{"color":{"text":"var:preset|color|red"}}}},"textColor":"red","textAlign":"","content":"Geological storage: a sustainable solution","level":2,"levelOptions":[],"placeholder":"","lock":[],"metadata":[],"align":"","className":"wp-block-heading has-red-color has-text-color has-link-color","backgroundColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Geological storage: a sustainable solution<\/h2>\n","innerContent":["\n

    Geological storage: a sustainable solution<\/h2>\n"],"rendered":"\n

    Geological storage: a sustainable solution<\/h2>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"The proposed solution in France, as in many other countries, is geological storage. The principle is to contain and isolate waste, far from the biosphere underground, using geological barriers, i.e. host rock, and engineered barriers (isolation of waste with layers of glass, steel, concrete, and clay materials). In France, Andra (Agence Nationale pour la gestion des D\u00e9chets RAdioactifs, the country\u2019s national radioactive waste management agency) is tasked with implementing this solution. In the framework of Cig\u00e9o (Centre Industriel de stockage G\u00c9Ologique, industrial geological storage center) project, located in Meuse\/Haute-Marne, the candidate host rock is a clay rock, called Callovo-Oxfordian claystone. This rock was chosen in particular due to its geological stability, its ability to contain radionuclides 2, and its very low permeability. The depth of the layer, approximately 500 meters, combined with its thickness of approximately 150 meters and its extremely low permeability can guarantee effective isolation of waste for several centuries. The planned storage system consists of a network of tunnels connected to the surface by access shafts. A set of micro-tunnels is planned in each tunnel where high-level radioactive waste will be stored. In addition, larger-diameter micro-tunnels are planned for intermediate-level long-lived waste. The challenges of the design and construction of such a system are in some ways similar to the issues facing major civil engineering projects such as deep tunnels, including the design of tunnels and tunnel support systems to prevent failure and to limit deformations to acceptable values. The exothermic nature of radioactive waste and the very low permeability of the rock provide additional challenges. Nevertheless, the major difference is in terms of project life span: whereas radioactive waste storage spans several centuries, civil engineering projects last a few decades. To demonstrate the feasibility of geological storage and study the behavior of the candidate host rock, an underground research laboratory was built by Andra, starting back in the 2000s, near the location of a future storage project. This laboratory provides the opportunity to test different tunnel excavation methods and support systems, as well as to conduct in-situ tests and experiments.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    The proposed solution in France, as in many other countries, is geological storage. The principle is to contain and isolate waste, far from the biosphere underground, using geological barriers, i.e. host rock, and engineered barriers (isolation of waste with layers of glass, steel, concrete, and clay materials). In France, Andra (Agence Nationale pour la gestion des D\u00e9chets RAdioactifs<\/em>, the country\u2019s national radioactive waste management agency) is tasked with implementing this solution. In the framework of Cig\u00e9o (Centre Industriel de stockage G\u00c9Ologique<\/em>, industrial geological storage center) project, located in Meuse\/Haute-Marne, the candidate host rock is a clay rock, called Callovo-Oxfordian claystone. This rock was chosen in particular due to its geological stability, its ability to contain radionuclides 2<\/a><\/sup>, and its very low permeability. The depth of the layer, approximately 500 meters, combined with its thickness of approximately 150 meters and its extremely low permeability can guarantee effective isolation of waste for several centuries. The planned storage system consists of a network of tunnels connected to the surface by access shafts. A set of micro-tunnels is planned in each tunnel where high-level radioactive waste will be stored. In addition, larger-diameter micro-tunnels are planned for intermediate-level long-lived waste. The challenges of the design and construction of such a system are in some ways similar to the issues facing major civil engineering projects such as deep tunnels, including the design of tunnels and tunnel support systems to prevent failure and to limit deformations to acceptable values. The exothermic nature of radioactive waste and the very low permeability of the rock provide additional challenges. Nevertheless, the major difference is in terms of project life span: whereas radioactive waste storage spans several centuries, civil engineering projects last a few decades. To demonstrate the feasibility of geological storage and study the behavior of the candidate host rock, an underground research laboratory was built by Andra, starting back in the 2000s, near the location of a future storage project. This laboratory provides the opportunity to test different tunnel excavation methods and support systems, as well as to conduct in-situ tests and experiments.<\/p>\n","innerContent":["\n

    The proposed solution in France, as in many other countries, is geological storage. The principle is to contain and isolate waste, far from the biosphere underground, using geological barriers, i.e. host rock, and engineered barriers (isolation of waste with layers of glass, steel, concrete, and clay materials). In France, Andra (Agence Nationale pour la gestion des D\u00e9chets RAdioactifs<\/em>, the country\u2019s national radioactive waste management agency) is tasked with implementing this solution. In the framework of Cig\u00e9o (Centre Industriel de stockage G\u00c9Ologique<\/em>, industrial geological storage center) project, located in Meuse\/Haute-Marne, the candidate host rock is a clay rock, called Callovo-Oxfordian claystone. This rock was chosen in particular due to its geological stability, its ability to contain radionuclides 2<\/a><\/sup>, and its very low permeability. The depth of the layer, approximately 500 meters, combined with its thickness of approximately 150 meters and its extremely low permeability can guarantee effective isolation of waste for several centuries. The planned storage system consists of a network of tunnels connected to the surface by access shafts. A set of micro-tunnels is planned in each tunnel where high-level radioactive waste will be stored. In addition, larger-diameter micro-tunnels are planned for intermediate-level long-lived waste. The challenges of the design and construction of such a system are in some ways similar to the issues facing major civil engineering projects such as deep tunnels, including the design of tunnels and tunnel support systems to prevent failure and to limit deformations to acceptable values. The exothermic nature of radioactive waste and the very low permeability of the rock provide additional challenges. Nevertheless, the major difference is in terms of project life span: whereas radioactive waste storage spans several centuries, civil engineering projects last a few decades. To demonstrate the feasibility of geological storage and study the behavior of the candidate host rock, an underground research laboratory was built by Andra, starting back in the 2000s, near the location of a future storage project. This laboratory provides the opportunity to test different tunnel excavation methods and support systems, as well as to conduct in-situ tests and experiments.<\/p>\n"],"rendered":"\n

    The proposed solution in France, as in many other countries, is geological storage. The principle is to contain and isolate waste, far from the biosphere underground, using geological barriers, i.e. host rock, and engineered barriers (isolation of waste with layers of glass, steel, concrete, and clay materials). In France, Andra (Agence Nationale pour la gestion des D\u00e9chets RAdioactifs<\/em>, the country\u2019s national radioactive waste management agency) is tasked with implementing this solution. In the framework of Cig\u00e9o (Centre Industriel de stockage G\u00c9Ologique<\/em>, industrial geological storage center) project, located in Meuse\/Haute-Marne, the candidate host rock is a clay rock, called Callovo-Oxfordian claystone. This rock was chosen in particular due to its geological stability, its ability to contain radionuclides 2<\/a><\/sup>, and its very low permeability. The depth of the layer, approximately 500 meters, combined with its thickness of approximately 150 meters and its extremely low permeability can guarantee effective isolation of waste for several centuries. The planned storage system consists of a network of tunnels connected to the surface by access shafts. A set of micro-tunnels is planned in each tunnel where high-level radioactive waste will be stored. In addition, larger-diameter micro-tunnels are planned for intermediate-level long-lived waste. The challenges of the design and construction of such a system are in some ways similar to the issues facing major civil engineering projects such as deep tunnels, including the design of tunnels and tunnel support systems to prevent failure and to limit deformations to acceptable values. The exothermic nature of radioactive waste and the very low permeability of the rock provide additional challenges. Nevertheless, the major difference is in terms of project life span: whereas radioactive waste storage spans several centuries, civil engineering projects last a few decades. To demonstrate the feasibility of geological storage and study the behavior of the candidate host rock, an underground research laboratory was built by Andra, starting back in the 2000s, near the location of a future storage project. This laboratory provides the opportunity to test different tunnel excavation methods and support systems, as well as to conduct in-situ tests and experiments.<\/p>\n"},{"blockName":"core\/heading","attrs":{"style":{"elements":{"link":{"color":{"text":"var:preset|color|red"}}}},"textColor":"red","textAlign":"","content":"Geomechanical aspects","level":2,"levelOptions":[],"placeholder":"","lock":[],"metadata":[],"align":"","className":"wp-block-heading has-red-color has-text-color has-link-color","backgroundColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Geomechanical aspects<\/h2>\n","innerContent":["\n

    Geomechanical aspects<\/h2>\n"],"rendered":"\n

    Geomechanical aspects<\/h2>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"Geomechanical aspects play a significant role in the phenomena at play in a geological storage system in clay rocks. For the duration of a storage site\u2019s life span, from tunnel construction to long-term exothermic waste storage, the host rock is subjected to a range of mechanical, hydraulic, and thermal loadings. The porous nature of the clay rocks, their extremely low permeabilities, and the presence of clayey minerals make their response highly dependent on multiphysics couplings. Accordingly, tunnel excavation causes deformations of the rock, and local variations in the pore water pressure acting in its microstructure, generating time-dependent water flows and deformations. The heat emitted by radioactive waste and its progressive diffusion create temperature gradients in the rock, causing instantaneous thermal expansion of the rock and variations in the pore water pressure. These in turn result in water flows and deformations. In-depth understanding of these phenomena is essential for the design of the geological storage system.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Geomechanical aspects play a significant role in the phenomena at play in a geological storage system in clay rocks. For the duration of a storage site\u2019s life span, from tunnel construction to long-term exothermic waste storage, the host rock is subjected to a range of mechanical, hydraulic, and thermal loadings. The porous nature of the clay rocks, their extremely low permeabilities, and the presence of clayey minerals make their response highly dependent on multiphysics couplings. Accordingly, tunnel excavation causes deformations of the rock, and local variations in the pore water pressure acting in its microstructure, generating time-dependent water flows and deformations. The heat emitted by radioactive waste and its progressive diffusion create temperature gradients in the rock, causing instantaneous thermal expansion of the rock and variations in the pore water pressure. These in turn result in water flows and deformations. In-depth understanding of these phenomena is essential for the design of the geological storage system.<\/p>\n","innerContent":["\n

    Geomechanical aspects play a significant role in the phenomena at play in a geological storage system in clay rocks. For the duration of a storage site\u2019s life span, from tunnel construction to long-term exothermic waste storage, the host rock is subjected to a range of mechanical, hydraulic, and thermal loadings. The porous nature of the clay rocks, their extremely low permeabilities, and the presence of clayey minerals make their response highly dependent on multiphysics couplings. Accordingly, tunnel excavation causes deformations of the rock, and local variations in the pore water pressure acting in its microstructure, generating time-dependent water flows and deformations. The heat emitted by radioactive waste and its progressive diffusion create temperature gradients in the rock, causing instantaneous thermal expansion of the rock and variations in the pore water pressure. These in turn result in water flows and deformations. In-depth understanding of these phenomena is essential for the design of the geological storage system.<\/p>\n"],"rendered":"\n

    Geomechanical aspects play a significant role in the phenomena at play in a geological storage system in clay rocks. For the duration of a storage site\u2019s life span, from tunnel construction to long-term exothermic waste storage, the host rock is subjected to a range of mechanical, hydraulic, and thermal loadings. The porous nature of the clay rocks, their extremely low permeabilities, and the presence of clayey minerals make their response highly dependent on multiphysics couplings. Accordingly, tunnel excavation causes deformations of the rock, and local variations in the pore water pressure acting in its microstructure, generating time-dependent water flows and deformations. The heat emitted by radioactive waste and its progressive diffusion create temperature gradients in the rock, causing instantaneous thermal expansion of the rock and variations in the pore water pressure. These in turn result in water flows and deformations. In-depth understanding of these phenomena is essential for the design of the geological storage system.<\/p>\n"},{"blockName":"core\/heading","attrs":{"style":{"elements":{"link":{"color":{"text":"var:preset|color|red"}}}},"textColor":"red","textAlign":"","content":"Development of design tools","level":2,"levelOptions":[],"placeholder":"","lock":[],"metadata":[],"align":"","className":"wp-block-heading has-red-color has-text-color has-link-color","backgroundColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Development of design tools<\/h2>\n","innerContent":["\n

    Development of design tools<\/h2>\n"],"rendered":"\n

    Development of design tools<\/h2>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"The design of radioactive waste geological storage infrastructure requires numerical simulations at the scale of the structure to predict the system\u2019s performances during the different stages of its life. These simulations require constitutive laws tailored to different materials, under conditions representative of the modelled storage situation. Identification of these constitutive laws and assessment of their parameters are based mainly on the laboratory\u2019s experimental studies. The low permeability of the rock and the potential for expansion of clay minerals make experiments relatively complex and potentially long. Experimental results must be analyzed and interpreted in conjunction with theoretical models and, in some cases using numerical simulations. The efficiency of these approaches is verified via comparison with in-situ measurements and observations made in the underground laboratory.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    The design of radioactive waste geological storage infrastructure requires numerical simulations at the scale of the structure to predict the system\u2019s performances during the different stages of its life. These simulations require constitutive laws tailored to different materials, under conditions representative of the modelled storage situation. Identification of these constitutive laws and assessment of their parameters are based mainly on the laboratory\u2019s experimental studies. The low permeability of the rock and the potential for expansion of clay minerals make experiments relatively complex and potentially long. Experimental results must be analyzed and interpreted in conjunction with theoretical models and, in some cases using numerical simulations. The efficiency of these approaches is verified via comparison with in-situ measurements and observations made in the underground laboratory.<\/p>\n","innerContent":["\n

    The design of radioactive waste geological storage infrastructure requires numerical simulations at the scale of the structure to predict the system\u2019s performances during the different stages of its life. These simulations require constitutive laws tailored to different materials, under conditions representative of the modelled storage situation. Identification of these constitutive laws and assessment of their parameters are based mainly on the laboratory\u2019s experimental studies. The low permeability of the rock and the potential for expansion of clay minerals make experiments relatively complex and potentially long. Experimental results must be analyzed and interpreted in conjunction with theoretical models and, in some cases using numerical simulations. The efficiency of these approaches is verified via comparison with in-situ measurements and observations made in the underground laboratory.<\/p>\n"],"rendered":"\n

    The design of radioactive waste geological storage infrastructure requires numerical simulations at the scale of the structure to predict the system\u2019s performances during the different stages of its life. These simulations require constitutive laws tailored to different materials, under conditions representative of the modelled storage situation. Identification of these constitutive laws and assessment of their parameters are based mainly on the laboratory\u2019s experimental studies. The low permeability of the rock and the potential for expansion of clay minerals make experiments relatively complex and potentially long. Experimental results must be analyzed and interpreted in conjunction with theoretical models and, in some cases using numerical simulations. The efficiency of these approaches is verified via comparison with in-situ measurements and observations made in the underground laboratory.<\/p>\n"},{"blockName":"core\/heading","attrs":{"style":{"elements":{"link":{"color":{"text":"var:preset|color|red"}}}},"textColor":"red","textAlign":"","content":"Research at the Navier laboratory","level":2,"levelOptions":[],"placeholder":"","lock":[],"metadata":[],"align":"","className":"wp-block-heading has-red-color has-text-color has-link-color","backgroundColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Research at the Navier laboratory<\/h2>\n","innerContent":["\n

    Research at the Navier laboratory<\/h2>\n"],"rendered":"\n

    Research at the Navier laboratory<\/h2>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"The Navier laboratory conducts research activities related to the aforementioned challenges, and in collaboration with different agencies and organizations tasked with radioactive waste management. Many of them are conducted at the laboratory to explore the behavior of different storage system materials under mechanical, hydraulic, and thermal loads, to develop constitutive laws. Integration of these equations into numerical simulation tools enables the analysis and prediction of storage system performances during the different stages of its life. Analysis of data from in-situ instrumentation, measurements and experiments in Andra's underground research laboratory provides a complementary view and demonstrates the system\u2019s response under conditions closer to actual storage conditions. Advanced numerical modelling tools are deployed in the analysis of this data. The complementarity of all these approaches, in-lab studies, theoretical developments, numerical simulations, and in-situ experiments and measurements offers a unique opportunity for multidisciplinary research in the service of a major project.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    The Navier laboratory conducts research activities related to the aforementioned challenges, and in collaboration with different agencies and organizations tasked with radioactive waste management. Many of them are conducted at the laboratory to explore the behavior of different storage system materials under mechanical, hydraulic, and thermal loads, to develop constitutive laws. Integration of these equations into numerical simulation tools enables the analysis and prediction of storage system performances during the different stages of its life. Analysis of data from in-situ instrumentation, measurements and experiments in Andra's underground research laboratory provides a complementary view and demonstrates the system\u2019s response under conditions closer to actual storage conditions. Advanced numerical modelling tools are deployed in the analysis of this data. The complementarity of all these approaches, in-lab studies, theoretical developments, numerical simulations, and in-situ experiments and measurements offers a unique opportunity for multidisciplinary research in the service of a major project.<\/p>\n","innerContent":["\n

    The Navier laboratory conducts research activities related to the aforementioned challenges, and in collaboration with different agencies and organizations tasked with radioactive waste management. Many of them are conducted at the laboratory to explore the behavior of different storage system materials under mechanical, hydraulic, and thermal loads, to develop constitutive laws. Integration of these equations into numerical simulation tools enables the analysis and prediction of storage system performances during the different stages of its life. Analysis of data from in-situ instrumentation, measurements and experiments in Andra's underground research laboratory provides a complementary view and demonstrates the system\u2019s response under conditions closer to actual storage conditions. Advanced numerical modelling tools are deployed in the analysis of this data. The complementarity of all these approaches, in-lab studies, theoretical developments, numerical simulations, and in-situ experiments and measurements offers a unique opportunity for multidisciplinary research in the service of a major project.<\/p>\n"],"rendered":"\n

    The Navier laboratory conducts research activities related to the aforementioned challenges, and in collaboration with different agencies and organizations tasked with radioactive waste management. Many of them are conducted at the laboratory to explore the behavior of different storage system materials under mechanical, hydraulic, and thermal loads, to develop constitutive laws. Integration of these equations into numerical simulation tools enables the analysis and prediction of storage system performances during the different stages of its life. Analysis of data from in-situ instrumentation, measurements and experiments in Andra's underground research laboratory provides a complementary view and demonstrates the system\u2019s response under conditions closer to actual storage conditions. Advanced numerical modelling tools are deployed in the analysis of this data. The complementarity of all these approaches, in-lab studies, theoretical developments, numerical simulations, and in-situ experiments and measurements offers a unique opportunity for multidisciplinary research in the service of a major project.<\/p>\n"},{"blockName":"core\/image","attrs":{"id":7089,"width":"358px","height":"auto","sizeSlug":"full","linkDestination":"none","align":"center","blob":"","url":"https:\/\/ingenius.ecoledesponts.fr\/wp-content\/uploads\/2024\/11\/Triaxial-cell-system-used-to-study-the-thermo-hydro-mechanical-behavior-of-geomaterials-Credit-Jean-Claude-Moschetti.jpg","alt":"","caption":"Triaxial cell system used to study the thermo-hydro-mechanical behavior of geomaterials. Credit: Jean-Claude Moschetti","lightbox":[],"title":"","href":"","rel":"","linkClass":"","aspectRatio":"","scale":"","linkTarget":"","lock":[],"metadata":[],"className":"wp-block-image aligncenter size-full is-resized","style":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    \"\"
    Triaxial cell system used to study the thermo-hydro-mechanical behavior of geomaterials. Credit: Jean-Claude Moschetti<\/em><\/figcaption><\/figure>\n","innerContent":["\n
    \"\"
    Triaxial cell system used to study the thermo-hydro-mechanical behavior of geomaterials. Credit: Jean-Claude Moschetti<\/em><\/figcaption><\/figure>\n"],"rendered":"\n
    \"\"
    Triaxial cell system used to study the thermo-hydro-mechanical behavior of geomaterials. Credit: Jean-Claude Moschetti<\/em><\/figcaption><\/figure>\n"},{"blockName":"core\/footnotes","attrs":{"lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","fontSize":"","fontFamily":"","borderColor":""},"innerBlocks":[],"innerHTML":"","innerContent":[],"rendered":""}],"seo":{"title":"Underground radioactive waste storage: contributions from geomechanics"},"media":{"img":"\"\"","src":"https:\/\/ingenius.ecoledesponts.fr\/wp-content\/uploads\/2024\/11\/DV010961_Damien_Valente_Terra.jpg"},"url":"\/en\/articles\/underground-radioactive-waste-storage-contributions-from-geomechanics\/","related":{"post":[],"author":[{"title":"Siavash Ghabezloo","url":"\/en\/authors\/siavash-ghabezloo\/","id":"5341","media":"\"\"","slug":"siavash-ghabezloo"}],"subject":[{"title":"Energy, Ecology & Climate","url":"\/en\/subjects\/energy-ecology-climate\/","id":"937","media":"\"\"","slug":"energy-ecology-climate"}],"category":[{"title":"Article collection","url":"\/en\/articles\/category\/dossier\/","id":"1720","media":"","slug":"dossier","_related_post_type":"folder"},{"title":"Articles","url":"\/en\/articles\/category\/articles\/","id":"1716","media":"","slug":"articles","_related_post_type":""}],"folder":[{"title":"Nuclear power : history, risks and challenges","url":"\/en\/folders\/nuclear-power-history-risks-and-challenges\/","id":"6913","media":"\"\"","slug":"nuclear-power-history-risks-and-challenges"}]},"translated":"https:\/\/ingenius.ecoledesponts.fr\/articles\/stockage-souterrain-des-dechets-radioactifs-contributions-de-la-geomecanique\/","icon":"icon-article","duration":"4","custom_excerpt":"In France, approximately 52% of energy consumed is from low-carbon sources, mainly stemming from nuclear energy and renewables, placing the country among the world leaders in this field. However, this position comes with major challenges in terms of managing radioactive waste from nuclear activities. The country is planning on geological storage to secure this waste in the long term, a solution involving complex technical and geomechanical challenges, requiring in-depth research in which the Navier Laboratory has been actively participating for the past two decades.","duration_type":"","_links":{"self":[{"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/posts\/7087","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/comments?post=7087"}],"version-history":[{"count":5,"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/posts\/7087\/revisions"}],"predecessor-version":[{"id":7222,"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/posts\/7087\/revisions\/7222"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/media\/7173"}],"wp:attachment":[{"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/media?parent=7087"}],"wp:term":[{"taxonomy":"article-types","embeddable":true,"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/article-types?post=7087"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}