Repository site data report for unsaturated tuff, Yucca Mountain, Nevada

Abstract

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Numerical Modeling of Isothermal and Nonisothermal Flow in Unsaturated Fractured Rock: A Review

“…Such studies can be valuable for waste package and repository design, as well as for the development of techniques for monitoring repository performance. The chief limitation of numerical modeling applications at this point appears to be that important data are either unavailabl,e or have a large range of variability [Peters et ai., 1984;Guzowski et ai., 1983;Tien et al 1985]. It should also be pointed out that the presently available numerical simulators have been constructed on the basis of general principles of fluid and heat flow.…”

Environmental Geochemistry of Radioactive Contamination

“…Because of the diversity of solutions, minerals, and radionuclides that could be present at contaminated sites and potential waste disposal repository sites, a large body of empirical radionuclide sorption data has been generated. Databases of K d values that can be used to estimate pdf's for various geologic media are summarized by Barney (1981a,b), Tien et al (1985), Bayley et al (1990), U.S. DOE (1988), McKinley and Scholtis (1992), Triay et al (1997), the U.S. Environmental Protection Agency (1999a,b) and Krupka and Serne (2000). Methods used to specify pdf's for K d s for use with sampling techniques such as Latin Hypercube Sampling (Iman and Shortencarier, 1984;Helton and Davis, 2002) have been described by Siegel et al (1983Siegel et al ( , 1989, Wilson et al (1994) and Rechard (1996).…”

“…DOE, 1996) Americium is strongly sorbed by tuffaceous rocks from Yucca Mountain in waters of low ionic strength (Triay et al, 1997). In a compilation by Tien et al (1985), americium K d s obtained with tuff in J-13 water ranged from 130-13,000 ml g -1 . Average values for devitrified, vitric and zeolitized tuff were 2975, 1430 and 1513 ml g -1 , respectively.…”

“…The range of groundwater compositions sampled at the site is discussed by Perfect et al (1995). Numerous geochemical studies have been carried out in high-Eh waters from the alluvium and tuffaceous rocks (e.g., UZ-TP-7) from the unsaturated zone, high-Eh waters from the saturated zone (e.g., J-13) within tuffaceous rocks, and in lower Eh-waters from a deeper Paleozoic carbonate aquifer (e.g., UE252p-1) (Tien et al, 1985;Triay et al, 1997). Table 5 describes the composition of water from the J-13 well, which has been used as a reference water in systematic studies of sorption, transport, and solubility (Nitsche et al, 1992).…”

“…Table 5 describes the composition of water from the J-13 well, which has been used as a reference water in systematic studies of sorption, transport, and solubility (Nitsche et al, 1992). Its composition is controlled by a number of processes including dissolution of vitric and devitrified tuff, precipitation of secondary minerals, and ion exchange (Tien et al, 1985;Triay et al, 1997). Table 7 contains the results of actinide solubility and speciation calculations for the J-13 and SKI-90 reference waters carried out using the MINTEQ2A code (Allison et al, 1991) as described by Langmuir (1997a).…”