Modeling fluid-rock interaction at Yucca Mountain, Nevada; A progress report, April 15, 1992

Viani, B.E.; Bruton, C.J.

doi:10.2172/138469

Cited by 10 publications

(14 citation statements)

References 28 publications

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“…Hydrothermal alteration of the tuff is not expected to alter its mineralogical or chemical composition outside the range displayed by the tuffs presently existing at Yucca Mountain (Viani and Bruton, 1992b). However, redistribution of relatively small quantities of silica, coupled with precipitation/dissolution of sorptive minerals could significantly change the behavior of a specific crushed tuff with respect to radionuclide transport.…”

Section: Backfillmentioning

confidence: 99%

Volume II: near-field and altered-zone environment report

Wilder¹

1996

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Section: Backfillmentioning

confidence: 99%

Volume II: near-field and altered-zone environment report

Wilder¹

1996

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“…Because most water penetrating the NFE is expected to enter via fracture flow, this section focuses on the composition of this water. Extensive previous studies (Bruton, 1996;Bruton et al, 1993;Bruton and Viani, 1992;Carroll et al, 1996;Johnson and Glassley, 1996;Knauss, 1987;Knauss and Copenhaver, 1995;Viani and Bruton, 1991 and see Section 5.3 of this report) have evaluated the likely interactions that may result through reaction primarily with matrix material. The results of these reports are not described here because the effect of such waters on repository materials is expected to be minimal.…”

Section: Chemical Composition Of Water In the Altered Zone Before Entmentioning

confidence: 89%

Near-field/altered-zone models report

Hardin¹

1998

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“…Figure 7 can be combined with Figure 9 to show the affinities of zeolites relative to other minerals. Note the supersaturation with respect to scolecite, mesolite, stilbite and the Ca end-member of a clinoptilolite solid solution (discussed by Viani and Bruton, 1992) at the downhole temperature of 246'C.…”

Section: Thermodvnamic Data For Zeolitesmentioning

confidence: 99%

Testing EQ3/6 and GEMBOCHS using fluid-mineral equilibria in the wairakei geothermal system

Bruton¹

1995

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The ability of the EQ3 and EQ6 geochemical modeling codes and the GEMBOCHS thermodynamic data bases (Wolery, 1992;Wolery and Daveler, 1992) to simulate geochemical changes in the post-emplacement environment at the potential Yucca Mountain, Nevada repository is being tested using observed mineral-fluid relations in the Taupo Volcanic Zone of New Zealand. In this report, comparisons between observed equilibria and simulations of field relations in the Wairakei geothermal system are used to test the codes and data bases in high temperature (>200°C) systems.Analysis of trends in water and gas chemistries and well discharge characteristics with time were used to identify a set of representative water and gas analyses from zones producing at about 25O'C. The most common vein minerals at this temperature are: wairakite, adularia, epidote, quartz, albite, chlorite, calcite, prehnite and pyrite (Reyes, Giggenbach and Christenson, 1993). Calculations were carried out using version 7.2a R134 of EQ3 and version 7.2a R130 of EQ6 and the SUPCRT and COM subsets of the R24 version of GEMBOCHS. Thermodynamic data bases using different data for Al aqueous species were used to identify the data set which produced the best matches between observed and calculated equilibria.Geochemical calculations with EQ3/6 using measured Al concentrations and thermodynamic data for Al aqueous species from Pokrovskii and Helgeson (in press) suggest that vein minerals are presently in equilibrium with subsurface fluids. Matrix replacement minerals, although of much greater variety and number than vein minerals owing to initial rock mineralogy (Reyes, Giggenbach and Christenson, 1993), are consistent with calculated mineral stabilities at downhole temperatures.The quartz geothermometer of Fournier (1983) describes aqueous SiOz concentrations at temperatures >200°C better than calculations using quartz data from Walther and Helgeson (1977). Calculations suggest that the free energy of wairakite, a high temperature Ca-zeolite, should be decreased by about l-l 5 kcal/mol at 25O'C. Calorimetric data for lower temperature zeolites such as clinoptilolite and stilbite from Johnson and co-workers (Johnson et al., 1991;Howell et al., 1990) appear to over-estimate the stability of these zeolites at temperatures > 2OOOC.The simulations described in this paper suggest that EQ6 can be used to identify facies of minerals that will be stable in various environments, but can not be used to predict the exact phase assemblage that is in equilibrium with a given water.

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Modeling fluid-rock interaction at Yucca Mountain, Nevada; A progress report, April 15, 1992

Cited by 10 publications

References 28 publications

Volume II: near-field and altered-zone environment report

Volume II: near-field and altered-zone environment report

Near-field/altered-zone models report

Testing EQ3/6 and GEMBOCHS using fluid-mineral equilibria in the wairakei geothermal system

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