Mass Transfer & Porous Media (MTPM) - Andra

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P/<strong>MTPM</strong>/1The free energy cost of forcing an anion into the interlayer was estimated using a set of biased simulationscombined with an unbiased scheme named Weighted Histogram Analysis Method (Roux 1995). Therelatively high value of this penalty (about 30 kJ/mol, that is 12 times the thermal energy at 298K) confirmsthat anions are excluded from the interlayer.CONCLUSIONThis study gives the first microscopic insights into the dynamics of exchange of water and ions betweeninterlayer porosity and microporosity. It will allow to better understand the different diffusion mechanismof water, cations and anions in clay minerals.References:ANDRA, Référentiel Matériaux, vol. 1 : Matériaux à base d’argiles gonflantes (2005)V. Marry and P. Turq, J. Phys. Chem. B 107, 1832 (2003)B. Roux, Comput. Phys. Comm. 91 (1-3), 275 (1995)Page 424INTERNATIONAL MEETING, SEPTEMBER 17...>...18, 2007, LILLE, FRANCECLAYS IN NATURAL & ENGINEERED BARRIERSFOR RADIOACTIVE WASTE CONFINEMENT
P/<strong>MTPM</strong>/2MULTI-SCALE CHARACTERISATIONOF MINERAL AND TEXTURAL SPATIALHETEROGENEITIES IN CALLOVO-OXFORDIAN ARGILITEAND ITS CONSEQUENCE ON SOLUTESPECIES DIFFUSION MODELLINGJ.C. Robinet 1 , N. Diaz 2 , P. Sardini1, F. Goutelard 2 , D. Menut 2 , J-C Parneix 3 ,S. Sammartino 4 , D. Prêt 1 and D. Coelho 51. HydrASA UMR CNRS 6532, 40 avenue du Recteur Pineau, Poitiers, 86022 Cedex, France.(jean.charles.robinet@etu.univ-poitiers.fr)2. CEA Saclay, L3MR/SECR, bât 450, 91190 GIF-SUR-YVETTE Cedex3. ERM, rue Albin Haller, Espace 10, 86000 POITIERS, France4. UMR INRA CSE, Domaine St-Paul. site Agroparc, Avignon, 84914 Cedex 9, France5. ANDRA, 1-7 rue Jean Monnet, Châtenay-Malabry, 92298 Cedex, France.The French National Agency for radioactive waste management (ANDRA) investigates the Callovo-Oxfordian argilite of the Eastern Paris Bassin as the host rock for high-level radioactive waste repositoryin deep geological formation. The modelling of radionuclides return times in the biosphere is carried outfrom parameters controlling the migration of radionucleides through this barrier (permeability, diffusioncoefficient…). Diffusion is assumed to be the main transport mechanism governing radionuclide migrationthrough this rock. Classically, the parameters controlling the diffusion processes (diffusion coefficient,porosity, sorption…) are obtained by bulk analyses considering the samples as homogeneous. Thesesparameters are then included into simulation models of solute species diffusion processes.Nevertheless, in recent studies, mineral and textural spatial heterogeneities have been visualised andquantified at different scale in the Callovo-Oxfordian argilite by imaging techniques adapted to clay rocks(autoradiographs, SEM images analysis, electronic microprobe analysis, µLIBS, tomography...) [1, 2, 3].The aim of this study is to set up, gauged and validated a methodology allowing the highlight and theunderstanding of the relation between the solute diffusion and the spatial distribution of minerals andtexture in clayey rocks.First, a multiscale characterisation from centimeter to micrometer were performed for a core sample ofCOx (DIR 1003 - EST 26059) using all of theses imaging techniques. In addition, classical bulk analysis(DRX, carbonate contents, chemical analysis…) were also achieved for the same core. Different mineraland porosity maps are obtained using this combining approach. Second, direct simulations of diffusionexperiment have been done from these maps using a random walk method in time domain (Time DomainDiffusion method [4]). Third, the distribution of diffusion parameters within the COx was obtained by aninversion method applied on experimental in diffusion maps for Eu and Cu tracer obtained using µLIBSanalysis.References:[1] S. Sammartino, Applied Clay Science, 23 (2003) p157.[2] Rachel Jorand, Ph D. Thesis, Université de Paris, France (2006).[3] D. Menut , FUNMIG report PID 3.2.4 (2007).[4] Sardini, Journal of. Contaminant Hydrology, 61, (2003) p339.INTERNATIONAL MEETING, SEPTEMBER 17...>...18, 2007, LILLE, FRANCECLAYS IN NATURAL & ENGINEERED BARRIERSFOR RADIOACTIVE WASTE CONFINEMENTPage 425
Page 1: Poster [MTPM]Mass Transfer & Porous
Page 7 and 8: P/MTPM/3DIFFUSION OF IONS IN UNSATU
Page 9: P/MTPM/4POROUS MEDIA CHARACTERIZATI
Page 12 and 13: P/MTPM/5Oxalate ionsQuartzQuartz +P
Page 14 and 15: P/MTPM/6borehole was capped with a
Page 16 and 17: P/MTPM/7Initial state with glass an
Page 18 and 19: P/MTPM/8The mesh of the elementary
Page 20 and 21: P/MTPM/9Moreover, using another sam
Page 22 and 23: P/MTPM/10Figure 1: Horizontal cross
Page 24 and 25: P/MTPM/11n t (mol)as received8 10 -
Page 26 and 27: P/MTPM/1210,9Degree of saturation (
Page 28 and 29: P/MTPM/13RESULTSFirst, we estimated
Page 30 and 31: P/MTPM/142.5Energy (M eV)1.6 1.7 1.
Page 32 and 33: P/MTPM/15C/Co10.90.80.70.60.50.40.3
Page 34 and 35: P/MTPM/16ModelIrmayvG-M1vG-M2vG-M3T
Page 36 and 37: P/MTPM/17Figure 1: Experimental HTO
Page 38 and 39: P/MTPM/18Diffusion experiments were
Page 40 and 41: P/MTPM/19Figure 1: Used mesh for co
Page 42 and 43: P/MTPM/201.81.61.41.2upstream compa
Page 44 and 45: P/MTPM/21490Pressure [bar]0 10 20 3
Page 46 and 47: 134P/MTPM/22through-diffusion exper
Page 48 and 49: P/MTPM/23HA (µg/g)3002001000(a):pH
Page 50 and 51: P/MTPM/24through each sample. The p
Page 52 and 53: P/MTPM/25FIRST RESULTSPreliminary c
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P/MTPM/26heterogeneous distribution
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P/MTPM/27Relative concentration (C-
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P/MTPM/280.75m0.25mTable 1: Cross s
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P/MTPM/29Figure 1: A. Scheme of the
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P/MTPM/30The presented theory is ex
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P/MTPM/31Furthermore, Van Loon et a
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P/MTPM/32RESULTSResults show that,
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P/MTPM/33Clay modellingPore size di
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P/MTPM/341.60E-11f H2-d total (kg.m
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P/MTPM/350.50η R ()0.400.300.200.1
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P/MTPM/36200Bq/g1801601401201008060
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P/MTPM/37Argilite (ionic strength 0
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P/MTPM/38-Samples cored at 12m were
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P/MTPM/39APPLICATIONSCORE 2D has be
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P/MTPM/40Figure 1: Sketch drawing o
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P/MTPM/41Figure 1: Thermal conducti
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P/MTPM/42Figure 2: Model of pore st
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P/MTPM/43The available data are con
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P/MTPM/44Figure 1: Spatial extensio
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P/MTPM/45Relative concentration / (
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P/MTPM/46Figure 2: Swelling pressur
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P/MTPM/47then used in the transport
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P/MTPM/4820181614121086Gas pressure
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Mass Transfer & Porous Media (MTPM) - Andra

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