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AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra B. Cochepin Direction Scientifique – Evaluation et Analyse de Performances Results and.

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Présentation au sujet: "AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra B. Cochepin Direction Scientifique – Evaluation et Analyse de Performances Results and."— Transcription de la présentation:

1 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra B. Cochepin Direction Scientifique – Evaluation et Analyse de Performances Results and new challenges in reactive transport simulations Journées Scientifiques du GNR MoMaS Novembre 2009 DS/EAP/

2 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra Presentation outline Main Andras goal: License Application (DAC) for HLW/ILLW repository in 2014 Reactive transport simulations at Andra Current limitations and progress axes Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/

3 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra Chemical transport simulations at Andra: schedule Objectives DAC st iteration of a chemical simulations for phenomenological behavior (PARS): conceptualization of problems and feasibility study (tools, model…) identifications of development of tools Use of reactive transport tolls for PA: to reduce conservatism, to define and quantify simplifications Reference run of chemical simulations for PARS (convergence with data acquisition programs) PA simulations dedicated to chemical processes Retention Degradation RN Source term Complementary studies in support to safety analysis and safety calculations for DAC Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/

4 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra Chemical transport simulations at Andra: a local description of complex processes Role of chemical transport simulations for Andra To acquire a detailed description of interfacial chemical processes of the repository and its surrounding geological media over 1 million years: Phenomenological simulations To participate to waste conditioning and design concept To contribute to performance assessment: Preliminary simulations Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/

5 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra Chemical transport simulations at Andra: Main processes Concrete degradation / alkaline plume Safety operating Durability HLW Iron corrosion Glass degradation Specific ILLW Bituminized waste ILLW/HLW RN integration Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/

6 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra Chemical transport simulations at Andra: Calculation specific features Interfacial problems Short distances A question of number of unknowns with highly non-linear equations Over a long period Not a matter of mesh with millions of elements Performance of algorithms Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/

7 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra Chemical transport simulations at Andra: numerical tools Phreeqc (USGS) Advantages: robustness, flexibility in kinetic law definition, chemical processes (ion exchange, solid solution, high ionic strength…) Drawbacks: problems with many kinetically defined minerals, 1D transport (may be adjusted), porosity feedback Crunch (LBNL) Advantages: specifically made for minerals defined with kinetic laws, various solving methods (OS3D, GIMRT) Drawbacks: absence of equilibrium chemistry and high ionic strength treatment Hytec (Ecole des Mines) Advantages: multi-D, robustness of thermodynamic calculations Drawbacks: kinetic treatment Toughreact (LBNL) Advantages: unsaturated chemical transport simulations Drawbacks: coupling, numerical convergence Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/ Feedback from ANDRA, CEA and BRGM

8 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra New challenges: alkaline plume (Phreeqc) Concrete-clay interactions ~7000 cells, 30 minerals, years 40 CPU days Progress axes Feedback on porosity, parallelization, solving methods (C. de Dieuleveult thesis) Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/ t = 0t = 10 5 years

9 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra New challenges: carbonation 1/3 Diphasic simulations – Toughreact Drying physics Assessed phenomena: Gas phase diffusion of vapor Gas phase flow of vapor (under pressure gradient) Capillary flow of water Thermodynamic equilibrium liquid water/vapor Gas diffusion in liquid phase Influence of the temperature Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/

10 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra New challenges: carbonation 2/3 Chemistry of carbonation Near 40 mineral phases kinetically controlled, temperature Need new expressions of kinetic laws /approximations due to the unsaturated conditions Mineral reactivity depending on saturation state, CO 2 instantaneous solubilization, influence of the water released from carbonation processes on hydraulics, precipitation of other minerals... Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/ Trotignon et al (CEA)

11 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra New challenges: carbonation 3/3 Simulation performances ~100 cells (concrete/argillites, water/air/CO 2 ), 1 processor: 100 years simulated in 6 months CPU (time step limited by gas diffusion) Coupling algorithm SNIA /SIA Progress axes Solving method/numerical coupling more efficient Chemistry feedback on transport (porosity, hydraulics,…) Evolution of material texture (passivating precipitation, saturation control of kinetic laws…) … Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/

12 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra New challenges: organic matter/ bituminized waste Conceptual problems concerning the source term Flux control (need to be representative), degradation kinetics A complex chemistry high concentrations, redox, microbial activity Progress axes Efficiency of algorithms concerning the kinetically controlled chemistry Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/

13 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra New challenges: corrosion (glass, steel) Glass Phenomenological models still need to be adjusted with experimental evidences How to represent a non crystallized material (gel)? Solid solution? Steel Non porous medium Progressive consumption/expanding secondary products H 2 production (gas bubbles?) Progress axes Unsaturated simulations Kinetics of processes Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/

14 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra New challenges: chemical-transport-mechanics coupling 3 applications: Degradation of argillaceous materials swelling properties of chemically degraded clays Degradation of cementitious materials/steel corrosion mechanic behaviour of waste disposal components Carbonation shrinkage, cracking mechanic behaviour of waste disposal components (B. Bary, CEA) Preliminary studies Chemical transport simulations supplies mechanic simulations: Mineral dissolution/precipitation volume variation, deformation (LMS) Progress axes Mechanic feedback on transport properties (cracking) Adapting mesh Efficiency of dedicated solving methods Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/

15 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra Chemical transport simulations at Andra: performance assessment PRELIMINARY Simulations Assessment of error impacts made by phenomenon simplification in performance calculations PAMINA European project: comparison of Cs transfer represented either by Kd/SL or thermodynamic models Calculation helping to radioactive waste package dimensioning Example : Influence of organic matter on radionuclide migration Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/

16 AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra Conclusion and prospects Advances since 2005 Enhanced capacity to take into account integrated and complex geochemical systems Alimented by experimental programs which provides up to date conceptual models A huge step is about to be made with unsaturated chemical transport simulations Confidence in safety calculations is increased by preparatory simulations Still to come More efficient solving method/coupling algorithms New coupling (adding of unsaturated conditions/mechanics) High performance (parallelization, optimization,…) Journées Scientifiques du GDR MoMaS Novembre 2009 DS/EAP/


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