Measurement of unsaturated hydraulic conductivity and chemical transport in Yucca Mountain Tuff: Milestone Report 3044-WBS1.2.3.4.1.4.1

Conca, James L.

doi:10.2172/140400

Cited by 4 publications

(4 citation statements)

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“…To address these problems, an unsaturated flow apparatus based on open-flow centfigation was developed in which hydraulic steady-state is achieved rapidly in any porous media by using an adjustable, whole-body driving force in combination with precision fluid flow (Conca, 1993 ;Conca and Wright, 1992;Wrighx et al, 1994). The UFA achieves hydraulic steady-state rapidly, in hours, even at very low water contents, and is actually a Darcy's Law machine in that the operator adjusts both the flw and the driving force, and attains any desired hydraulic steady-state within the operating range.…”

Section: Introductionmentioning

confidence: 99%

Engineered Barrier System performance requirements systems study report. Revision 02

Balady¹

1997

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Section: Introductionmentioning

confidence: 99%

Engineered Barrier System performance requirements systems study report. Revision 02

Balady¹

1997

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“…1988) but this method is not designed to investigate unsaturated flow. To address these problems, an unsaturated flow apparatus (UFAm) based on open centrifugation was developed in which hydraulic steady-state is achieved rapidly in most geologic media at low water contents (Conca and Wright, 1992;Conca, 1993).…”

Section: Introductionmentioning

confidence: 99%

Measurement of unsaturated hydraulic conductivity in the Bandelier Tuff at Los Alamos

Conca¹,

Mockler²

1995

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This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its usc would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer er, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.. SUMMARY Hydraulic conductivities, K, were experimentally determined as a function of volumetric water content, 0, in Bandelier Tuff cores from Los Alamos, New Mexico. These data were used to determine the feasibility of applying a new unsaturated flow technology (UFAm) to further hydrologic studies of tuffaceous rocks at Los Alamos. The K(8) relationships for eight cores of Bandelier Tuff from boreholes AAA and AAB were measured using the UFA and, together with their in situ water contents, were used to determine transient water flux into these samples at the time of sampling. If the system is at steady-state, then these flux values correspond to the recharge through those points, a situation often encountered in semi-arid to arid regions such as Los Alamos and other sites in the western United States.

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“…Using measured or calculated fluid pressures and measured flow rates, the relative permeability that corresponds to the measured average saturation is calculated. The steady‐state approach has been widely used for measuring flow and transport parameters under partially saturated conditions (Nimmo et al, 1987, 1994, 2002; Nimmo and Mello, 1991; Conca and Wright, 1992, 1998; Conca, 1993; Conca et al, 1997, 1998; ASTM, 2000; Seaman et al, 2002; Basha and Mina, 1999; Caputo and Nimmo, 2005; Wright et al, 1994). Both the IFC and UFA methods ignore the gradient in capillary pressure along the length of the sample.…”

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Unsaturated Hydraulic Conductivity Measurements with Centrifuges: A Review

Berg

Perfect

et al. 2009

Vadose Zone Journal

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531G are often faced with making quantitative predictions of the migration of multiple fl uids through the subsurface. Software packages for simulating multiphase fl uid fl ow through porous media are well developed (e.g., ECLIPSE Schlumberger reservoir simulator, HYDRUS-1D and 2D [Šimůnek et al., 1998, 1999], and STOMP [White and Oostrom, 2000]) and fi nd wide applications in both research and industry. Among the physical properties of the porous medium that are required as model inputs, the capillary pressure and unsaturated hydraulic conductivity (or relative permeability) vs. fl uid saturation functions are often considered the most critical (Christiansen, 2001). Accurate and effi cient measurements of these functions are therefore of considerable importance for ensuring accurate simulations.Th e advantages of measuring the capillary pressure and relative permeability functions on core samples using centrifuges have been recognized from as early as the beginning of the 20th century (Briggs and McLane, 1907;Gardner, 1937). Th e fact that the centrifugal acceleration is many times greater than Earth's gravitational acceleration and that it acts equally on all fl uids throughout the sample (which accelerates the adaptation to changes in boundary conditions) is seen as an attractive way to speed up multiphase fl uid fl ow experiments. Besides this advantage, the fl ow and transport processes take place under more ideal and controlled conditions than experiments conducted under normal gravity, leading to more accurate measurements that extend across a wider range of saturations (Nimmo, 1990;Nakajima and Stadler, 2006).Conventional permeameter techniques for measuring the intrinsic permeability, k, under normal gravity conditions have also been applied to a centrifugal fi eld. A clear distinction is made between experiments in which water is supplied from an internal or an external source, and if the fl ow experiment is conducted under constant-or falling-head conditions (Nimmo et al., 2002). Th e relevant analytical equations describing saturated fl ow under these diff erent combinations of experimental conditions were presented in Nimmo and Mello (1991) and Nimmo et al. (2002).Centrifuge techniques for measuring the relative permeability function can be divided into steady-and transient-state methods. In steady-state centrifuge experiments, the sample and fl uids are subject to a time-invariant centrifugal acceleration. Pressure and fl ow conditions at the inlet end face (the sample face closest to the center of rotation) are set so that steady-state fl ow conditions develop for the wetting fl uid with time. Two steady-state methods, referred to by Nimmo et al. (2002) as internal fl ow control (IFC) and unsaturated fl ow apparatus (UFA), have been used for multiphase fl ow applications. A: IFC, internal fl ow control; UFA, unsaturated fl ow apparatus. R AConduc ng drainage or imbibi on experiments in a centrifugal force fi eld has long been recognized as a valid and efficient way to determine capillary pressure-...

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Measurement of unsaturated hydraulic conductivity and chemical transport in Yucca Mountain Tuff: Milestone Report 3044-WBS1.2.3.4.1.4.1

Abstract: ABSTRACT

Cited by 4 publications

References 14 publications

Engineered Barrier System performance requirements systems study report. Revision 02

Engineered Barrier System performance requirements systems study report. Revision 02

Measurement of unsaturated hydraulic conductivity in the Bandelier Tuff at Los Alamos

Unsaturated Hydraulic Conductivity Measurements with Centrifuges: A Review

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