Radionuclide migration at the Koongarra uranium deposit, Northern Australia – Lessons from the Alligator Rivers analogue project

Payne, Timothy E.; Airey, Peter

doi:10.1016/j.pce.2006.04.008

Cited by 33 publications

(18 citation statements)

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“…This is an important distinction: in order to up-scale a SCM in terms of heterogeneity, a new, somewhat simplified conceptual model was necessary. Even with the required simplifications of the GC approach, good agreement to data has been observed (Davis et al [1998], Payne et al [2006], and Waite et al [2000]). Furthermore, the added simplicity of the GC approach, allows for a semi-mechanistic inclusion of metal sorption as a function of solution chemistry into transport scenarios which has lead to better descriptions of metal/radionuclide transport compared to more empirical models.…”

Section: Bench Scale/wet Chemical Methods For Characterizationmentioning

confidence: 80%

“…The GC approach assumes that a natural mineral matrix is too complex to be understood, and fits hypothetical reactions to measured sorption behavior. The CA approach uses sorption behavior determined through sorption experiments on single mineral phases, and then mathematically combines the behavior based on the proportions of the single minerals present in the matrix (for fuller discussions and some applications to real data see Honeyman [1984], Davis et al [1998], Payne et al [2006], and Waite et al [2000]). …”

Section: Bench Scale/wet Chemical Methods For Characterizationmentioning

confidence: 99%

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Upscaling of Long-Term U9VI) Desorption from Pore Scale Kinetics to Field-Scale Reactive Transport Models

Miller¹

2009

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Environmental systems exhibit a range of complexities which exist at a range of length and mass scales. Within the realm of radionuclide fate and transport, much work has been focused on understanding pore scale processes where complexity can be reduced to a simplified system. In describing larger scale behavior, the results from these simplified systems must be combined to create a theory of the whole. This process can be quite complex, and lead to models which lack transparency. The underlying assumption of this approach is that complex systems will exhibit complex behavior, requiring a complex system of equations to describe behavior. This assumption has never been tested. The goal of the experiments presented is to ask the question: Do increasingly complex systems show increasingly complex behavior?Three experimental tanks at the intermediate scale (Tank #1: 2.4m x 1.2m x 7.6cm, Tank #2: 2.4m x 0.61m x 7.6cm, Tank #3: 2.4m x 0.61m x 0.61m (LxHxW)) have been completed. These tanks were packed with various physical orientations of different particle sizes of a uranium contaminated sediment from a former uranium mill near Naturita, Colorado. Steady state water flow was induced across the tanks using constant head boundaries. Pore water was removed from within the flow domain through sampling ports/wells; effluent samples were also taken. Each sample was analyzed for a variety of analytes relating to the solubility and transport of uranium. Flow fields were characterized using inert tracers and direct measurements of pressure head.The results show that although there is a wide range of chemical variability within the flow domain of the tank, the effluent uranium behavior is simple enough to be described using a variety of conceptual models. Thus, although there is a wide range in variability caused by pore scale behaviors, these behaviors appear to be smoothed out as uranium is transported through the tank. This smoothing of uranium transport behavior transcends many of the physical and chemical heterogeneities added to the tank experiments.iv

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Section: Bench Scale/wet Chemical Methods For Characterizationmentioning

confidence: 80%

Section: Bench Scale/wet Chemical Methods For Characterizationmentioning

confidence: 99%

Upscaling of Long-Term U9VI) Desorption from Pore Scale Kinetics to Field-Scale Reactive Transport Models

Miller¹

2009

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“…Therefore, the U concentration for some groundwaters (samples [6][7][8][9][10][11][12][13][14] is low and the 234 U/ 238 U AR is high due to efficient recoil from precipitated uraninite [26,35]. The high 234 U/ 238 U AR values of the waters reflect preferential dissolution of 234 U relative to 238 U from rocks due to the α-recoil effect during the α-decay of 238 U to 234 Th [5,36,37]. However, dissolution of aquifer rocks decreases the 234 U/ 238 U AR in groundwater because this ratio in rocks is close to unity.…”

Section: Activity Ratios Of U-series Radionuclidementioning

confidence: 99%

“…Therefore older U ore bodies, which are dissolved by oxidizing or saline groundwaters in the Shihongtan aquifer could be the source of U in the high-U groundwaters (samples [4][5][6][7][8][9][15][16][17] Figure 4 shows the relationship between the 234 U/ 238 U AR and U concentration from water samples. All samples with a low U concentration show disequilibria with high 234 U/ 238 U AR values (>1-2).…”

Section: Fluid Mixingmentioning

confidence: 99%

“…Bulk dissolution of most rocks >1 Ma that have not experienced recent water-rock interactions yield dissolved uranium (U) with a 234 U/ 238 U activity ratio (AR) near 1 [1][2][3][4][5][6][7]. However, 234 U enters solutions preferentially as the results of α-recoil damage of crystal-lattice sites containing 234 U, radiation-induced oxidation of 234 U, and preferential leaching of 234 U from the α-recoil tracks [8].…”

Section: Introductionmentioning

confidence: 99%

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Uranium-Series Disequilibria in the Groundwater of the Shihongtan Sandstone-Hosted Uranium Deposit, NW China

et al. 2015

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Uranium (U) concentration and the activities of 238 U, 234 U, and 230 Th were determined for groundwaters, spring waters, and lake water collected from the Shihongtan sandstone-hosted U ore district and in the surrounding area, NW China. The results show that the groundwaters from the oxidizing aquifer with high dissolved oxygen concentration (O 2 ) and oxidation-reduction potential (Eh) are enriched in U. The high U concentration of groundwaters may be due to the interaction between these oxidizing groundwaters and U ore bodies, which would result in U that is not in secular equilibrium. Uranium is re-precipitated as uraninite on weathered surfaces and organic material, forming localized ore bodies in the sandstone-hosted aquifer. The 234 U/ 238 U, 230 Th/ 234 U, and 230 Th/ 238 U activity ratios (ARs) for most water samples show obvious deviations from secular equilibrium (0.27-2.86), indicating the presence of water-rock/ore interactions during the last 1.7 Ma and probably longer. The 234 U/ 238 U AR generally increases with decreasing U concentrations in the groundwaters, suggesting that mixing of two water sources may occur in the aquifer. This is consistent with the fact that most of the U ore bodies in the deposit have a tabular shape originati from mixing between a relatively saline fluid and a more rapidly flowing U-bearing meteoric water.

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Uranium: Radionuclides

Vandenhove

Hurtgen

Payne

2005

Encyclopedia of Inorganic Chemistry

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This article describes the occurrence, chemistry, and bioavailability of uranium (U) in terrestrial and aquatic environments, its analysis in environmental samples, and remedial measures applicable to uranium‐contaminated water and soil. Uranium is widely distributed throughout the world. There are three main isotopes present in natural uranium, which comprises 234 U (0.0055%), 235 U (0.72%), and 238 U (99.27%). Uranium can occur either in its reduced state (U(IV)), which is generally highly immobile, or in its more soluble and mobile (U(VI)) state. Uranium mobility and bioavailability are governed by oxidation state, complexation by organic and inorganic ligands, pH, sorption by minerals including clays and hydroxides, and interactions with organic matter. In uncontaminated surface waters uranium content is generally low (<1 ppb). Most groundwaters are low in uranium but the concentration range is large (<0.001–2600 ppb), resulting from the interaction of groundwater with naturally occurring uranium‐bearing materials or anthropogenic contamination sources. Since groundwater is a major source for drinking water, various methods have been developed to remove uranium from potable water. Similar methods are applied in wastewater treatment. Extraction and processing of uranium ore or minerals containing natural radionuclides has resulted in the generation of waste streams. The major challenge associated with these contaminated waste streams, residues, or sites is typically the larger volumes of material and the relatively low specific activities.

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Radionuclide migration at the Koongarra uranium deposit, Northern Australia – Lessons from the Alligator Rivers analogue project

Cited by 33 publications

References 50 publications

Upscaling of Long-Term U9VI) Desorption from Pore Scale Kinetics to Field-Scale Reactive Transport Models

Upscaling of Long-Term U9VI) Desorption from Pore Scale Kinetics to Field-Scale Reactive Transport Models

Uranium-Series Disequilibria in the Groundwater of the Shihongtan Sandstone-Hosted Uranium Deposit, NW China

Uranium: Radionuclides

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