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Transcript of AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS © Andra B. Cochepin Direction...
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 23-25
Novembre 2009
DS/EAP/09-0081
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Presentation outline
Main Andra’s 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 23-25 Novembre 2009
DS/EAP/09-0081
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Chemical transport simulations at Andra: schedule
Objectives DAC 2014
2007-20091st iteration of a chemical simulations for phenomenological behavior (PARS): conceptualization of problems and feasibility study (tools, model…) identifications of development of toolsUse of reactive transport tolls for PA: to reduce conservatism, to define and quantify simplifications
2010-2012Reference run of chemical simulations for PARS (convergence with data acquisition programs)PA simulations dedicated to chemical processes
Retention Degradation RN Source term
2013-2014Complementary studies in support to safety analysis and safety calculations for DAC
Journées Scientifiques du GDR MoMaS 23-25 Novembre 2009
DS/EAP/09-0081
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Chemical transport simulations at Andra: a local description of complex processes
Role of chemical transport simulations for AndraTo 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 23-25 Novembre 2009
DS/EAP/09-0081
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Chemical transport simulations at Andra: Main processes
Concrete degradation / alkaline plumeSafety operating
Durability
HLW Iron corrosion
Glass degradation
Specific ILLWBituminized waste
ILLW/HLWRN integration
Journées Scientifiques du GDR MoMaS 23-25 Novembre 2009
DS/EAP/09-0081
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Chemical transport simulations at Andra: Calculation specific features
Interfacial problemsShort distances
A question of number of unknowns with highly non-linear equations
Over a long periodNot a matter of mesh with millions of elements
Performance of algorithms
Journées Scientifiques du GDR MoMaS 23-25 Novembre 2009
DS/EAP/09-0081
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© 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 calculationsDrawbacks: kinetic treatment
Toughreact (LBNL)Advantages: unsaturated chemical transport simulations Drawbacks: coupling, numerical convergence
Journées Scientifiques du GDR MoMaS 23-25 Novembre 2009
DS/EAP/09-0081
Feedback from ANDRA, CEA and BRGM
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
New challenges: alkaline plume (Phreeqc)
Concrete-clay interactions
~7000 cells, 30 minerals, 100 000 years 40 CPU days
Progress axesFeedback on porosity, parallelization, solving methods (C. de Dieuleveult thesis)
Journées Scientifiques du GDR MoMaS 23-25 Novembre 2009
DS/EAP/09-0081
t = 0 t = 105 years
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© 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 23-25 Novembre 2009
DS/EAP/09-0081
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
New challenges: carbonation 2/3
Chemistry of carbonationNear 40 mineral phases kinetically controlled, temperature
Need new expressions of kinetic laws /approximations due to the unsaturated conditions
Mineral reactivity depending on saturation state, CO2 instantaneous solubilization, influence of the water released from carbonation processes on hydraulics, precipitation of other minerals...
Journées Scientifiques du GDR MoMaS 23-25 Novembre 2009
DS/EAP/09-0081
0,00
0,04
0,08
0,12
0,16
0 0,01 0,02 0,03 0,04 0,05 0,06Distance (m)
Calcite - 5 y
Portlandite - 5 y
Calcite - 20 y
Portlandite - 20 y
fraction vol.
COLIS_1
0,00
0,04
0,08
0,12
0 0,01 0,02 0,03 0,04 0,05 0,06Distance (m)
CSH 1.6
Si02 amorphe
CSH 1.2
CSH 0.8
Straetlingite
fraction vol.
COLIS_1 20 y
Trotignon et al. 2009 (CEA)
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
New challenges: carbonation 3/3
Simulation performances~100 cells (concrete/argillites, water/air/CO2), 1 processor:
100 years simulated in 6 months CPU (time step limited by gas diffusion)
Coupling algorithm SNIA /SIA
Progress axesSolving 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 23-25 Novembre 2009
DS/EAP/09-0081
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
New challenges: organic matter/ bituminized waste
Conceptual problems concerning the source termFlux control (need to be representative), degradation kinetics
A complex chemistryhigh concentrations, redox, microbial activity
Progress axesEfficiency of algorithms concerning the kinetically controlled chemistry
Journées Scientifiques du GDR MoMaS 23-25 Novembre 2009
DS/EAP/09-0081
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
New challenges: corrosion (glass, steel)
GlassPhenomenological models still need to be adjusted with experimental evidences
How to represent a non crystallized material (gel)? Solid solution?
SteelNon porous medium
Progressive consumption/expanding secondary products
H2 production (gas bubbles?)
Progress axesUnsaturated simulations
Kinetics of processes
Journées Scientifiques du GDR MoMaS 23-25 Novembre 2009
DS/EAP/09-0081
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© 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 axesMechanic feedback on transport properties (cracking)
Adapting mesh
Efficiency of dedicated solving methods
Journées Scientifiques du GDR MoMaS 23-25 Novembre 2009
DS/EAP/09-0081
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© 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 dimensioningExample : Influence of organic matter on radionuclide migration
Journées Scientifiques du GDR MoMaS 23-25 Novembre 2009
DS/EAP/09-0081
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Conclusion and prospects
Advances since 2005Enhanced 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 comeMore efficient solving method/coupling algorithms
New coupling (adding of unsaturated conditions/mechanics)
High performance (parallelization, optimization,…)
Journées Scientifiques du GDR MoMaS 23-25 Novembre 2009
DS/EAP/09-0081