Mass Transfer & Porous Media (MTPM) - Andra

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P/<strong>MTPM</strong>/1210,9Degree of saturation (dimensionless)0,80,70,6BVE-103 (finalconditions)BVE-96 (initialconditions)0,50 20 40 60 80 100 120Distance from the borehole head (cm)Figure 1: Degrees of saturation obtained at 150°C from boreholes BVE-96 and BE-103 representing theinitial and final conditions of a 1year dry air ventilationfrom the borehole head and are quantitatively well correlated to the degree of saturation especially for theBVE-103 borehole. Theses cracks are therefore attributed to desaturation cracks. Autoradiographs obtainedafter rock fragments impregnation with a 14 C-radioactive resin enabled us to quantify the role offracturation in total porosity by comparing matrix porosity to total porosity. The matrix porosity decreasesup to about 40cm then slightly increases in the borehole end. This reduction of matrix porosity was alsoobserved around drifts excavated in the well compacted Tournemire argillite submitted to a natural dry-airventilation and was attributed to the reduction of volume by water loss (Altinier, 2006; Matray et al;, 2007).High resolution X-rays tomography was performed with the aim of visualizing the organization of porosityin 3D at a micrometric scale and quantifying porosity and minerals. The proportions of minerals estimatedby this method are consistent with the known mineralogy of Opalinus Clay (Gautschi, 2006). It alsoenabled us to verify the occurrence of desaturation cracks and to quantify their contribution to the totalporosity that appeared in good agreement with estimates of fracture and matrix porosity deduced fromautoradiographs.References:Altinier, A.M. (2006) Etude de la composition isotopique des eaux porales de l’argilite de Tournemire :Inter-comparaison des méthodes de mesure et relation avec les paramètres pétrophysiques. Thèse deDoctorat de l’Université de Paris Sud.Gautschi, A. (2006) The long-term Performance of a Clastone Barrier for a high-level Radioactive wasteRepository in Switzerland : An evaluation Using Multiple lines of evidence, Nagra, Wettingen,Switzerland geosciences and the Long Term Management of Radioactive Wastes. The geologicalSociety of London, Burlington Hose, 9 january 2006.Matray, J.M., Savoye, S. & Cabrera, J. (2007): Desaturation and structure relationships around drifts excavatedin the well-compacted Tournemire’s argillite (Aveyron, France): Engineering Geology 90, 1-16.Mayor, JC., Garcia-Sineriz, J.L., Velasco, M., Gomez-Hernandez, J., Lloret, A., Matray, J.M., Coste, F.,Giraud, A., Rothfuchs, T., Marshall, P., Fierz, T., Klubertanz, G. (2005). Ventilation Experiment inOpalinus Clay for the disposal of radioactive waste in underground repositories. (Project funded by theEuropean Communnity under the ‘EURATOM’ Programme 1998-2002 under contract N° FIKW-CT-2001-00126): EC Final Tech. Publ. Rept. CEC Nuclear Science & Technology Series Luxembourg pp. 41.Page 446INTERNATIONAL MEETING, SEPTEMBER 17...>...18, 2007, LILLE, FRANCECLAYS IN NATURAL & ENGINEERED BARRIERSFOR RADIOACTIVE WASTE CONFINEMENT
P/<strong>MTPM</strong>/13EVALUATION OF PORE STRUCTUREIN COMPACTED SATURATED BENTONITEUSING NMR RELAXOMETRYT. Ohkubo 1 , H. Kikuchi 1 and M. Yamaguchi 21. Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194,Japan2. Institute of Research and Innovation, 1201 Takada, Kashiwa, Chiba, 277-0861, JapanINTRODUCTIONThe permeability and diffusivity of a compacted bentonite, which is a candidate buffer material in variousJapanese geological disposal system, have been examined to assess its barrier performance and provideinput for tailoring engineering barriers to specific geological environments. Despite considerableaccumulation of experimental data in the past, the relationship of pore structures (both the interlayer poresof the clay and the intralayer pores resulting from particle aggregation) to aqueous pathways in compactedsaturated bentonite is not yet fully understood. In order to clarify some of the factors involved, we haveapplied NMR relaxometry (relaxation distribution analysis of 1 H NMR) to saturated compacted bentonite.NMR RELAXOMETRY AND EXPERIMENTAL PROCEDUREThe proton longitudinal relaxation time, T 1 , measured by NMR of fluids in porous media, is stronglyinfluenced by fluid-solid interaction. One interesting application of such relaxation measurements is thedetermination of the surface-volume ratio of pores,1 S----- = ρ ⎛T 1 ⎝ 1V -- ⎞⎠pore(1)where ρ 1 is the surface relaxivity, S and V are the surface area and volume of the pore. In saturated clays,( S/V ) pore corresponds to the surface-volume ratio of pores filled with water. A possible source of surfacerelaxation is the presence of magnetic impurities along the pore wall, in this particular applicationparamagnetic ions like Mn 2+ and Fe 3+ in clay.Measurements were performed using an NMR spectrometer (Maran Ultra, Resonance Instrument, UK) at23.4 MHz. A saturation recovery sequence with 256 recovery values from 0.1 to 52 ms was used. Thedecay of nuclear magnetization obtained from these measurements was analyzed numerically using aninverse Laplace transformation (Provencher, 1982) to derive the T 1 distribution.MATERIALThe bentonite material examined is Kunigel VI, which is a Na-bentonite provided by Kunimine IndustriesCo., Ltd. Kunigel VI contains 47 wt% montmorillonite, 37 wt% chalcedony, 4 wt% plagioclase, 3 wt%analcime, 2 wt% calcite 2 wt% dolomite, 0.6 wt% quartz, and 0.6 wt% pyrite (total 96.2 wt%). Due to itshigh surface area and content of magnetic impurities, the relaxation time measured is expected to be dueto the montmorillonite component. Do you think it is worth adding this sentence?Compacted bentonitesamples with dry densities, ρ c , of 1.33 and 1.80 Mg/m 3 were prepared. After compaction, saturation of thesamples with distilled water was carried out at fixed volume over a period of 2 months. Montmorillonitesols and gels were also prepared by adding distilled water to Kunipia F, which is a purified bentonitecontaining over 98 wt% montmorillonite, to estimate the surface relaxivity of the clay component of theKunigel.INTERNATIONAL MEETING, SEPTEMBER 17...>...18, 2007, LILLE, FRANCECLAYS IN NATURAL & ENGINEERED BARRIERSFOR RADIOACTIVE WASTE CONFINEMENTPage 447
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 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 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,
Page 68 and 69: P/MTPM/33Clay modellingPore size di
Page 70 and 71: P/MTPM/341.60E-11f H2-d total (kg.m
Page 72 and 73: P/MTPM/350.50η R ()0.400.300.200.1
Page 74 and 75: 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
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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
Page 96 and 97:
P/MTPM/47then used in the transport
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P/MTPM/4820181614121086Gas pressure
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