Glass corrosion A record of the past? A predictor of the future?

Adams, P. B.

doi:10.1016/0022-3093(84)90150-9

Cited by 42 publications

(17 citation statements)

References 6 publications

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Section: Nuclear Melt Glass Dissolutionmentioning

confidence: 99%

Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test

Pohlmann¹,

Pohll²,

Chapman³

et al. 2004

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EXECUTIVE SUMMARYGroundwater flow and radionuclide transport at the Shoal underground nuclear test are characterized using three-dimensional numerical models, based on site-specific hydrologic data. The objective of this modeling is to provide the flow and transport models needed to develop a contaminant boundary defining the extent of radionuclide-contaminated groundwater at the site throughout 1,000 years at a prescribed level of confidence. This boundary will then be used to manage the Project Shoal Area (PSA) for the protection of the public and the environment.The PSA is located in north-central Nevada along the crest of the Sand Springs Range. The Shoal nuclear test was detonated on October 26, 1963. It had a yield of 12 kilotons and was located at a depth of 367 m below land surface. The Sand Springs Range is comprised of fractured granite and is bounded on the east and west by alluvium-filled valleys. Faulting is present in the range, with a prominent shear zone and other major faults striking southwest to northeast across the site. Groundwater recharge occurs by infiltration of precipitation on the mountain range, with regional discharge occurring in the valleys. A groundwater divide occurs below the upland area of the range, separating flow to the east and west. The nuclear test is located on the eastern side of the divide such that groundwater from the nuclear test area moves toward Fairview Valley.Geologic and hydrologic data to support the modeling were gathered during three different periods. First, regional hydrogeologic investigations and detailed site geology studies were conducted in support of the nuclear test in the 1960s. Second, the U.S. Department of Energy (DOE) drilled and tested four hydrologic characterization wells in 1996 that provide site-specific hydraulic parameters. After the 1996 data collection, an interim groundwater model was developed by . It was the basis for a Data Decision Analysis (Pohll et al., 1999b) that evaluated model uncertainties and identified optimum methods of reducing uncertainty. As a result of the recommendations of the DDA, the third data collection period occurred in 1999 to 2000, when DOE drilled and tested another four wells at the site, and conducted a tracer test between two of the wells.Data from these studies support a fundamental conceptual model for groundwater flow at the PSA of groundwater flow through the fractured granite, toward the adjoining valleys. Recharge is uniformly distributed across the surface of the Sand Springs Range, originating as precipitation. A hydrologic divide coincides with the upland areas of the range, forming a no-flow boundary west of the nuclear test. A region of higher conductivity and higher porosity is located around the cavity and chimney as a result of the nuclear test. A significant refinement to the conceptual model as a result of the 1999 field work is the recognition of a low-conductivity shear zone creating an impermeable no-flow boundary east of the nuclear test, dipping to the west.Alternate conceptual mode...

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Section: Nuclear Melt Glass Dissolutionmentioning

confidence: 99%

Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test

Pohlmann¹,

Pohll²,

Chapman³

et al. 2004

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“…It has been shown that the hydrothermal alteration of glass is primarily a function of the initial glass composition, the reaction temperature, the solution chemistry, and the duration of reaction (for a recent review see Adams 1984). Each of these factors has an effect on the composition, crystallinity, and amount of each alteration phase.…”

Section: Discussionmentioning

confidence: 99%

Analysis of an altered simple silicate glass using different mineral and glass standards

Mazer

Bates

1989

Scanning

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Quantitative analyses of alteration products formed during the aqueous corrosion of glass were performed using four different sets of standards: relevant mineral standards, an NBS glass standard, unreacted simple silicate glass, and the unreacted center of the reacted glass. A simple silicate glass (containing Na, Mg, Al, Si, and Ca) was reacted in water vapor at 200° C for 14 days. Up to eight alteration phases, including a Mg‐rich smectite clay and a zeolite intermediate in composition between Ca‐harmotome and phillipsite, formed on the glass surface. A set of energy‐dispersed spectra (EDS) of the bulk glass, the clay, and the zeolite were collected from a polished cross‐section of the reacted sample. The sum of the elemental weight percents varied by as much as 48% using the different standards. These differences are due to poor electrical conductivity through the clay layer. When the analyses were normalized to 100%, the differences between analyses using the standards were small (less than 10 wt% for individual cations and <5 total wt%). Normalization is inappropriate in the analysis of hydrated alteration phases, which contain a significant amount of water. The inability of the EDS system to detect water requires that absolute analyses be used to estimate the water content of the alteration phases. The bulk glass standard analyses were best suited for this purpose. In addition, use of the bulk glass standard is preferable in our application because spectra of the altered layer and bulk glass can be acquired from the same specimen. Analytical errors that may occur due to poor conductivity through the reacted layer, drifting probe currents, or varying thickness of the carbon coating are also reduce.

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“…The relationship between the reducing surface area and mass dissolved results in an exponential function, so that most of the mass is lost in early time (50 percent lost in 800 years) with a trailing tail in later years. This predicted timeframe for dissolution is very rapid compared to the history of natural glasses, such as obsidians, basalts, and tektites, which are millions of years old (Jantzen and Plodinec (1984), and even man-made glasses, which have survived for 3500 years (Adams, 1984). It is likely that the dissolution calculations overpredict the process because rate-reducing processes have been neglected, e.g., protection of the glass mass from additional dissolution by the formation of a mantle of reaction products (clays and zeolites), and reduction in internal surface area as interstices are clogged by reaction products (as found in the reduced post-reaction surface area measured by Essington and Sharp, 1965).…”

Section: Dissolution Rate For Shoal Nuclear Melt Glassmentioning

confidence: 99%

“…It is assumed that the radionuclide components of the glass will be released as the glass dissolves in bulk, ignoring any intra-glass diffusion that might result in variations in leaching rates from one species to another. This can be considered as etching of the glass, where the structure is broken down, rather than leaching of individual components (Adams, 1984). White (1983) t Average of six nuclear melt glass samples, as reported by Smith (1995) **Average of 34 Shoal granite samples obtained at 50 ft intervals in borehole ECH-D (University of Nevada, 1965) tFezO3 rather than FeO Analysis from Appendix 7 *** Dissolution of glass under the geochemical conditions found at Shoal is expected based on thermodynamic considerations.…”

Section: Nuclear Melt Glass Dissolutionmentioning

confidence: 99%

Evaluation of groundwater flow and transport at the Shoal underground nuclear test: An interim report

Pohll¹,

Chapman²,

Hassan³

et al. 1998

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Glass corrosion A record of the past? A predictor of the future?

Cited by 42 publications

References 6 publications

Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test

Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test

Analysis of an altered simple silicate glass using different mineral and glass standards

Evaluation of groundwater flow and transport at the Shoal underground nuclear test: An interim report

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