Mass Transfer & Porous Media (MTPM) - Andra

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P/<strong>MTPM</strong>/8The mesh of the elementary calculation domain is presented on Figure2 for a coarse refinement. Two finest refinement levels leading to200,000 and 1,600,000 cells were used for calculations.Radionuclide transport calculations performed for each refinementlevel mesh were analyzed by comparing time dependent fluxes at theupper domain boundary outlet.Our mesh and time step convergence calculations point out that MHFEand VF schemes applied on non-parralellepipedic hexahedral cells forflow and transport calculations in highly heterogeneous media gavesatisfactory results. Mesh refinement level as well as time steprequired for converged calculations were exhibited an analyzed in termof cpu time needed.Figure 2: Coarser mesh refinementlevel of calculation domain(24 000 cells).References:Gerardo-Giorda, L., Le Tallec, P., Nataf, F. (2004): A Robin-Robin preconditioner for stronglyheterogeneous advection-diffusion problems, Comput. Methods Appl. Mech. Engrg., 193, n° 9-11, 745-764Brezzi, F. and M. Fortin, M. (1991): Mixed and Hybrid Finite Methods, Springer-Verlag, New York, USA.Dabbene, F. (1998): Mixed Hybrid Finite Elements for Transport of Pollutants by Undergrounds Water,Proceedings of the 10th Int. Conf. on Finite Elements in Fluids, Tucson USA, January 5-8, pp. 456-461.Aavatsmark, I., Barkve, T., Boe, O., Mannseth, T. (1998): Discretization on unstructured grids forinhomogeneous, anisotropic media, Part I: Derivation of the methods, Siam J. Sci. Comput., 19, n°5,pp. 1700-1716.Le Potier, C. (2004): Finite volume in 2 or 3 dimensions for a diffusion convection equation applied toporous media with Cast3m Proceedings of the XV th Int. Conf. on Computational Methods in WaterResources, Chapel hill USA, June 13-17.Page 438INTERNATIONAL MEETING, SEPTEMBER 17...>...18, 2007, LILLE, FRANCECLAYS IN NATURAL & ENGINEERED BARRIERSFOR RADIOACTIVE WASTE CONFINEMENT
P/<strong>MTPM</strong>/9EXPERIMENTAL STUDY OF THE WATERPERMEABILITY OF A PARTIALLYSATURATED ARGILLITEC. Imbert 1 , P. Semete 2 , P. Desgree 2 , B. Février 2 , A. Courtois 3 , G. Touzé 1 .1. CEA Saclay, Laboratory of Concrete and Clay Behaviour, Buildings 158 & 133, F-91191 GIF-SUR-YVETTE, France ( christophe.imbert@cea.fr ), (gaetan.touze@cea.fr)2. Electricité De France (EDF), EDF R&D, Materials and Mechanics of Components Department,Avenue des Renardières, F-77818 MORET SUR LOING CEDEX, France( patrick.semete@edf.fr ), (patrick.desgree@edfgdf.fr)3. Electricité De France (EDF), EDF SEPTEN, 12-14 avenue Dutriévoz, 69628 VILLEURBANNE,FranceINTRODUCTIONTo increase the knowledge about the hydro-mechanical behaviour of indurated clays as host rock for theunderground disposal of radioactive waste, a series of laboratory experiments has been undertaken. Theexperiments focussed on the water permeability of the argillite for a large range of saturation states.Water permeability measurement is currently realised on saturated clayey materials or indurated clays. Forthe determination of such property as a function of the saturation degree, two main methods are identified:(i) the non-destructive survey of the evolution of the water content along a column of clay submitted to anuniaxial drying or imbibition process; (ii) the survey of the transient behaviour of a clay sample submittedto a little variation of suction, this measurement being repeated many times along the suction range. In thispaper focus will be given on the second type of experiment. Associated with an H-M model theexperimental data provide the water permeability of the argillite along a drying path. Considering the widerange of suction which is studied, the transfer of water occurs in vapour phase. So in fact this method canbe considered as a means of determining the vapour diffusion coefficient.EXPERIMENTAL METHODThe principle of the experimental technique is the following. A core sample from the Callovo-Oxfordianargillite has been cut into many cylindrical sub-samples. The core sample has been preserved from bothdrying and decompression thanks to a special cell. At the beginning, the core sample is considered asalmost saturated. In order to control the starting point, a stabilization step was made at 97% relativehumidity. Five groups of four samples have been submitted to a series of suction levels, along a dryingpath, from 97%, 92%, 90%, 84% and 80% relative humidity to 6.4% relative humidity for the last group.For each step, the suction is controlled inside a glass vessel thanks to a saturated saline solution. When thesurrounding suction is changed, a careful survey of the mass variation of the sample is made. So thekinetics of the transient phase is recorded. The next step is undertaken only after complete equilibrium ofthe sample. A special care is devoted to the control of temperature to 25°C during the whole experiment.The preparation of the samples includes a watertight coating placed on the lateral face and on the bottomface. So the experiment takes place in uniaxial conditions making possible the interpretation with a 1-Dmodel. Because the draining length is equal to the thickness of the cylinders, the duration of the transientdrying phase is maximized. So the survey of the mass variation is easy.Each group of samples gives four measurements of mass variation at each step. The different groups followa part of the drying path, so for each suction step many measurements are realized. The organisation ofthe experimental campaign provides a redundancy of the measurements.INTERNATIONAL MEETING, SEPTEMBER 17...>...18, 2007, LILLE, FRANCECLAYS IN NATURAL & ENGINEERED BARRIERSFOR RADIOACTIVE WASTE CONFINEMENTPage 439
Page 1: Poster [MTPM]Mass Transfer & Porous
Page 4 and 5: P/MTPM/1The free energy cost of for
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 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
Page 54 and 55: P/MTPM/26heterogeneous distribution
Page 56 and 57: P/MTPM/27Relative concentration (C-
Page 58 and 59: P/MTPM/280.75m0.25mTable 1: Cross s
Page 60 and 61: P/MTPM/29Figure 1: A. Scheme of the
Page 62 and 63: P/MTPM/30The presented theory is ex
Page 64 and 65: P/MTPM/31Furthermore, Van Loon et a
Page 66 and 67: 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
Page 78 and 79:
P/MTPM/38-Samples cored at 12m were
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P/MTPM/39APPLICATIONSCORE 2D has be
Page 82 and 83:
P/MTPM/40Figure 1: Sketch drawing o
Page 84 and 85:
P/MTPM/41Figure 1: Thermal conducti
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P/MTPM/42Figure 2: Model of pore st
Page 88 and 89:
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
Page 96 and 97:
P/MTPM/47then used in the transport
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P/MTPM/4820181614121086Gas pressure
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