Numerical studies of fluid and heat flow near high-level nuclear waste packages emplaced in partially saturated fractured tuff

Pruess, Karsten; Tsang, Yvonne; Wang, J.S.Y.

doi:10.2172/60565

Cited by 19 publications

(13 citation statements)

References 17 publications

(7 reference statements)

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“…Key issues include the extent of formation dry-out and liquid-phase exclusion from regions heated above the nominal boiling point, the formation and behavior of condensation zones, the potential development of fast preferential water flow paths, the migration of transient water pulses through heated regions, and the development of heat pipe conditions. There is a long track record of mathematical modeling studies devoted to thermally driven processes in the Yucca Mountain Project [Nitao, 1989;Nitao et al, 1992;Tsang, 1993, 1994;Pruess et al, 1984Pruess et al, , 1988Pruess et al, , 1985Pruess et al, , 1990aPruess, 1987, 1989]. Additionally, there have been many theoretical and experimental studies of the behavior of heat pipes primarily in porous media [McGuinness, 1996[McGuinness, , 1997Ramesh and Torrance, 1990;Stubos et al, 1993;Udell, 1985].…”

Section: Introductionmentioning

confidence: 99%

Laboratory experiments on heat‐driven two‐phase flows in natural and artificial rock fractures

Kneafsey¹,

Pruess²

1998

Water Resources Research

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Abstract. Water flow in partially saturated fractures under thermal drive may lead to fast flow along preferential localized pathways and heat pipe conditions. At the potential highlevel nuclear waste repository at Yucca Mountain, water flowing in fast pathways may ultimately contact waste packages and transport radionuclides to the accessible environment. Sixteen experiments were conducted to visualize heat-driven liquid flow in fracture models that included (1) assemblies of roughened glass plates, (2) epoxy replicas of rock fractures, and (3) a fractured specimen of Topopah Spring tuff. Continuous rivulet flow was observed for high liquid flow rates, intermittent rivulet flow and drop flow for intermediate flow rates, and film flow for lower flow rates and wide apertures. Heat pipe conditions (vapor-liquid counterflow with phase change) were identified in five of the seven experiments in which spatially resolved thermal monitoring was performed but not when vapor-liquid counterflow was hindered by very narrow apertures and when an inadequate working fluid volume was used. A combined program of field, laboratory, and theoretical studies is needed to gain an understanding of these processes so that they may be properly taken into account for waste package and repository design and for repository performance evaluation. Key issues include the extent of formation dry-out and liquid-phase exclusion from regions heated above the nominal boiling point, the formation and behavior of condensation zones, the potential development of fast preferential water flow paths, the migration of transient water pulses through heated regions, and the development of heat pipe conditions. There is a long track record of mathematical modeling studies devoted to thermally driven processes in the Yucca Mountain Project [Nitao, 1989;Nitao et al., 1992; Tsang, 1993, 1994;Pruess et al., 1984Pruess et al., , 1988Pruess et al., , 1985Pruess et al., , 1990a

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Section: Introductionmentioning

confidence: 99%

Laboratory experiments on heat‐driven two‐phase flows in natural and artificial rock fractures

Kneafsey¹,

Pruess²

1998

Water Resources Research

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“…There is a long record of mathematical modeling studies devoted to the prediction of the future thermal-hydrological conditions in the unsaturated environment [Nitao et al, 1992;Tsang, 1993, 1994;Pruess et al, 1984Pruess et al, , 1985Pruess et al, , 1988Pruess et al, , 1990aPruess, 1987, 1989]. Typically, these studies have demonstrated that a large, superheated dry rock region will form for several thousand years at Yucca Mountain, and that during this period, infiltrating liquid water is not expected to contact waste packages.…”

Section: Motivationmentioning

confidence: 99%

TH{_}PULSE: Program for Calculating Infiltration of Episodic Liquid Fingers in Superheated Rock Fractures - Theory, User's Manual and Sample Applications

Birkhölzer¹

2002

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This report describes the code TH_PULSE developed at the Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab). The code handles gravity-driven flow of episodic infiltration events entering above-boiling rock-temperature regions. Such temperature conditions are expected, for example, after emplacement of heat-generating nuclear waste in underground repositories. Complex fluid-flow and heat-transfer phenomena occur, as the infiltrating water is subject to vigorous boiling from the hot rock. A new efficient semi-analytical method is presented herein that simulates such phenomena. It is assumed that flow forms in localized preferential flow paths (referred to as "fingers").The first section of this report gives the conceptual and mathematical background for the solution scheme. The second section is a user's manual for TH_PULSE, providing all information required to run the code, including a detailed description of the input and output files. In the third section, the new solution scheme is applied to several test cases. Sample simulations are performed for conditions representative of the potential nuclear waste repository at Yucca Mountain, Nevada. A brief summary is given in Section 4.-IV -INTENTIONALLY LEFT BLANK.-V -

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“…This approximation substantially simplifies the flow problem. Pruess et al (1986) presented a model for a single equivalent continuum in unsaturated fractured rock in which hydraulic conductivity was taken as a sum of hydraulic conductivity from the porous medium and the fracture. Pruess et al (1990a,b) found that this approach was unacceptable in the presence of rapid flow transients, large fracture spacings, or with a very low permeability rock matrix.…”

Section: Single Equivalent Continuum Formulationmentioning

confidence: 99%

A compendium of fracture flow models, 1994

Diodato¹

1994

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Numerical studies of fluid and heat flow near high-level nuclear waste packages emplaced in partially saturated fractured tuff

Abstract: We have performed modeling studies on the simultaneous transport of heat, liquid water, vapor, and air in partially saturated fractured porous rock.

Cited by 19 publications

References 17 publications

Laboratory experiments on heat‐driven two‐phase flows in natural and artificial rock fractures

Laboratory experiments on heat‐driven two‐phase flows in natural and artificial rock fractures

TH{_}PULSE: Program for Calculating Infiltration of Episodic Liquid Fingers in Superheated Rock Fractures - Theory, User's Manual and Sample Applications

A compendium of fracture flow models, 1994

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