Papers by David Wronkiewicz
Pb isotope measurements of road dusts and background geologic materials in the Viburnum Trend resource extraction area of southeast Missouri (2011)
The isotopic composition of Pb in fugitive dust suspended by a vehicle from 13 unsurfaced roads i... more The isotopic composition of Pb in fugitive dust suspended by a vehicle from 13 unsurfaced roads in Missouri was measured to identify the source of Pb within an established long-term mining area. A three end member model using 207Pb/206Pb and concentration as tracers resulted in fugitive dust samples plotting in the mixing field of well characterized heterogeneous end members. End members selected for this investigation include the 207Pb/206Pb for 1) a Pb-mixture representing mine tailings, 2) aerosol Pb impacted soils within close proximity to the Buick secondary recycling smelter, and 3) an average of soils, rock cores and drill cuttings representing the background characteristics. Aqua regia total concentrations and 207Pb/206Pb of mining area dust suggest that 35.4- 84.3% of the source Pb in dust is associated with the mine tailings mixture, 9.1 to 52.7% is associated with the smelter mixture, and 0 to 21.6% is associated with background materials. Isotope ratios varied minimally ...
Exploration of modern microbialites with calcium and magnesium stable isotopes, mineralogy, and elemental composition: Storr’s Lake, San Salvador Island, The Bahamas
Goldschmidt2021 abstracts, 2021
Acta Carsologica, 2016
Constraints on the geological history of the karst system in southern Missouri, U.S.A. provided b... more Constraints on the geological history of the karst system in southern Missouri, U.S.A. provided by radiogenic, cosmogenic and physical/chemical characteristics of doline fill The Ozark Plateaus region of southern Missouri is underlain by dominantly carbonate marine platform rocks of Paleozoic age. The region has been sub-aerially exposed since the late Paleozoic and is characterized by extensive karst. To better understand the geologic history of this regional karst system, we examined the stratigraphic record preserved in the fill of a large doline near the largest spring in the region. Samples of fill from natural exposures and drill core were analyzed using thermoluminescence (TL) and 10Be cosmogenic techniques, and the physical/chemical characteristics of the fill material were determined by visual inspection, X-ray analyses, and grain-size measurements. Drill-hole data indicate that the allochthonous doline fill is 36.3 m thick and rests on at least 15.6 m of cave breakdown and sediment. The doline fill is divisible into 7 zones. Analysis of 10Be concentrations suggest that the entire doline fill was derived from local residuum during the middle (Illinoian) to late Pleistocene (Wisconsinan). X-ray diffraction analyses of clays throughout the doline fill indicate that they consist of nearly equal amounts of kaolinite and illite, consistent with terrestrial weathering.
Comparison of Completion and Heterogeneity Effect on CO2 Sequestration in S hallow and Deep Saline Aquifers
Proceedings of International Oil and Gas Conference and Exhibition in China, 2010
The effect of completion techniques and reservoir heterogeneity on CO2 storage and injectivity in... more The effect of completion techniques and reservoir heterogeneity on CO2 storage and injectivity in saline aquifers has been studied using a compositional reservoir simulator CMG-GEM. Two reservoir models were built using data extracted from publications, to represent a deep saline aquifer and a shallow aquifer. The effect of completion methods, including partial perforation of the reservoir net pay (partial completion), well geometry, orientation, location and length, on CO2 storage are discussed. Heterogeneity effect has been addressed considering three parameters: mean permeability, vertical to horizontal permeability ratio, and permeability variation. Sensitivity analysis was carried out using design of experiments (DOE) to determine the dominant factors affecting CO2 storage capacity and CO2 injectivity. Simulation results show that completing all layers, using horizontal wells set in upper layers with a length around 250-300 m are the most favorable choices for CO2 storage capacity in the aquifer examined. Mean permeability affects CO2 storage capacity and injectivity the most; kv/kh affects CO2 injectivity storage capacity more than permeability variation, Vk. More CO2 can be stored in the heterogeneous reservoirs with low mean permeability; however, high injectivity can be achieved in the uniform reservoirs with high mean permeability
Astrobiology, 2016
Microbialites found in the low-light-intensity, hypersaline waters of Storr's Lake (SL), San ... more Microbialites found in the low-light-intensity, hypersaline waters of Storr's Lake (SL), San Salvador Island, the Bahamas, were investigated with respect to their morphology, mineralogy, and microbial diversity. Previously described microbialite morphologies, as well as a newly identified "multi-cuspate" morphology, were observed at various depths. Electron microscopy analysis revealed the presence of angular, blocky, and needle-shaped crystals with mineralized cyanobacterial filaments and remains of exopolymeric substances. X-ray diffraction studies confirmed the presence of both Mg-calcite and aragonite in the plateau-mushroom and pinnacle mound microbialites, whereas only Mg-calcite was identified in the other microbialite morphotypes. A comprehensive molecular analysis using barcoded pyrosequencing of five different microbial mat communities identified at least 12 dominant bacterial phyla. Cyanobacteria were generally low in abundance and ranged from ∼0.01% in the ...
Environmental Pollution, 2016
The isotopic composition of lead (Pb) in fugitive dust suspended by a vehicle from 13 unsurfaced ... more The isotopic composition of lead (Pb) in fugitive dust suspended by a vehicle from 13 unsurfaced roads in Missouri was measured to identify the source of Pb within an established long-term mining area. A three end-member model using 207 Pb/ 206 Pb and concentration as tracers resulted in fugitive dust samples plotting in the mixing field of well characterized heterogeneous end members. End members selected for this investigation include the 207 Pb/ 206 Pb for 1) a Pb-mixture representing mine tailings, 2) aerosol Pbimpacted soils within close proximity to the Buick secondary recycling smelter, and 3) an average of soils, rock cores and drill cuttings representing the background conditions. Aqua regia total concentrations and 207 Pb/ 206 Pb of mining area dust suggest that 35.4e84.3% of the source Pb in dust is associated with the mine tailings mixture, 9.1e52.7% is associated with the smelter mixture, and 0e21.6% is associated with background materials. Isotope ratios varied minimally within the operational phases of sequential extraction suggesting that mixing of all three Pb mixtures occurs throughout. Labile forms of Pb were attributed to all three end members. The extractable carbonate phase had as much as 96.6% of the total concentration associated with mine tailings, 51.8% associated with smelter deposition, and 34.2% with background. The next most labile geochemical phase (Fe þ Mn Oxides) showed similar results with as much as 85.3% associated with mine tailings, 56.8% associated with smelter deposition, and 4.2% associated with the background soil.
Scientific basis for nuclear waste management XXII. Materials Research Society symposium proceedings: Volume 556
Materials Research Society Symposia Proceedings Materials Research Society, Jul 1, 1999
A. Materials 1 B. Apparatus 3 C. Procedure 4 D. Analytical Methods 6 LIST OF TABLES-Cont'd 19. Co... more A. Materials 1 B. Apparatus 3 C. Procedure 4 D. Analytical Methods 6 LIST OF TABLES-Cont'd 19. Comparison of Derived Lattice Constants for Sample IF with JCPDS Data 37 20. Comparison of IF Data with JCPDS Patterns 37 21. XRD Identification of Bottom White Cubes (1G) 22. XRD Identification of Sample 51 23. Comparison of Derived Lattice Constants with Reported Constants 24. XRD Identification of White Chunk (8J) 25. XRD Identification of Brown Clump (8M)
MRS Proceedings, 2002
ABSTRACTThe five-metal epsilon particle represents an important component with respect to the cor... more ABSTRACTThe five-metal epsilon particle represents an important component with respect to the corrosion of spent nuclear fuel as it is the principal host for 99Tc. This radionuclide has a high solubility in oxidizing environments (as TcO4 -), a half-life of 213,000 years, and has been proposed as a monitor for the corrosion rate of spent fuel. As such, an understanding of the corrosion processes affecting epsilon particles may have important implications on our ability to accurately assess radionuclide release rates from spent nuclear fuel.Non-radioactive metal powders were mixed in an atomic percent ratio of 40% Mo, 30% Ru, 15% Pd, 10% Re, and 5% Rh (Re used as a surrogate for Tc), a composition that simulates epsilon particles in spent reactor fuel [1,2]. The powders were electric arc-melted in the presence of an Ar-purged atmosphere. Scanning electron microscopy images of the as-cast samples denote a primary sample heterogeneity, with two distinct zones, each composed of a mixtur...
This document reports on the work done by the Nuclear Waste Management Section of the Chemical Te... more This document reports on the work done by the Nuclear Waste Management Section of the Chemical Technology Division (CMT), Argonne National Laboratory, in the period October 1993-September 1994. Studies have been performed to evaluate the performance of nuclear waste glass and spent fuel samples under unsaturated conditions (low volume water contact) that are likely to exist in the Yucca Mountain environment being considered as a potential site for a high-level waste repository. Tests with simulated waste glasses have been in progress for over eight years and demonstrate that actinides from initially fresh glass surfaces will be released as a result of the spallation of reacted glass layers from the surface, as the small volume of water passes over the waste form. The glass reaction appears to follow nearly linear reaction kinetics for the time period of testing and does not exhibit the decrease that is commonly observed during the intermediate stage of reaction in tests done with large volumes of water.
MRS Proceedings, 2002
ABSTRACTAn iron phosphate base glass and a simulated Hanford Tank Farm B (TFB) waste loaded iron ... more ABSTRACTAn iron phosphate base glass and a simulated Hanford Tank Farm B (TFB) waste loaded iron phosphate glass were reacted under both Product Consistency Test (PCT) and Vapor Hydration Test (VHT) conditions. Solution aliquots were collected following reaction of the TFB glass after the completion of a PCT at 90°C for time periods of 7, 49, 185, 274, and 365 days. Normalized element release patterns for sodium were highest of all the elements present, with values initially decreasing between 7 and 182 days and then increasing thereafter. Normalized release values for phosphorous declined between 49 and 182 days but increased thereafter, whereas calcium contents declined to and remained below the analytical detection limit after 182 days. Normalized element release patterns for Ce, Nd, and Fe were below 0.00045 g/m2 for all time periods tested. Amorphous iron oxide and elongate crystals (possibly apatite?) were noted as alteration products in both long-term PCT and short-term VHT f...
MRS Proceedings, 2002
ABSTRACTThe UO2 in spent nuclear fuel is unstable in the oxidizing conditions within the volcanic... more ABSTRACTThe UO2 in spent nuclear fuel is unstable in the oxidizing conditions within the volcanic tuffs at the proposed nuclear repository at Yucca Mountain, Nevada. Over time, the UO2 will oxidize and corrode, releasing actinides and fission products to the surrounding environment. However, uranyl (U6+) phosphates (autunite, phurcalite, sodium autunite, etc.) are stable in such an oxidizing environment. The mobility of released radionuclides may be greatly retarded if they can be incorporated into these naturally stable phosphate phases, while the complex structures, variable chemical compositions, and natural analogue occurrences of the uranyl phosphates suggests such a process is favorable. Current tests have focused on synthesizing such phases by reacting uranium oxynitrate or UO3 with a calcium, sodium, or potassium phosphate and a base (if necessary) in a Teflon reaction vessel. Excess water is added, and the solution is heated at 90°C for 7, 35, or 182 days. SEM analyses have...
CO2 Sequestration Potential in Missouri Shallow Sandstone Aquifers
International Oil and Gas Conference and Exhibition in China, 2010
The effect of completion techniques and reservoir heterogeneity on CO2 storage and injectivity in... more The effect of completion techniques and reservoir heterogeneity on CO2 storage and injectivity in saline aquifers has been studied using a compositional reservoir simulator CMG-GEM. Two reservoir models were built using data extracted from publications, to represent a deep saline aquifer and a shallow aquifer. The effect of completion methods, including partial perforation of the reservoir net pay (partial completion), well geometry, orientation, location and length, on CO2 storage are discussed. Heterogeneity effect has been addressed considering three parameters: mean permeability, vertical to horizontal permeability ratio, and permeability variation. Sensitivity analysis was carried out using design of experiments (DOE) to determine the dominant factors affecting CO2 storage capacity and CO2 injectivity. Simulation results show that completing all layers, using horizontal wells set in upper layers with a length around 250–300 m are the most favorable choices for CO2 storage capac...
MRS Proceedings, 1990
ABSTRACTRadiation may effect the long-term performance of glass in an unsaturated repository site... more ABSTRACTRadiation may effect the long-term performance of glass in an unsaturated repository site by interacting with air, water vapor, or liquid water. The present study examines (1) the effects of alpha or gamma irradiation in a water vapor environment, and (2) the influence of radiolytic products on glass reaction. Results Indicate that nitric and organic acids form in an irradiated water vapor environment and are dissolved in thin films of condensed water. Glass samples exposed to these conditions react faster and have a different assemblage of secondary phases than glasses exposed to nonirradiated water vapor environments.
The Role of Alteration Phases in Influencing the Kinetics of Glass Dissolution
MRS Proceedings, 1999
ABSTRACT The potential effect of alteration phases on the kinetics of glass corrosion has been ex... more ABSTRACT The potential effect of alteration phases on the kinetics of glass corrosion has been examined in a preliminary series of Product Consistency Tests (0.5, 1, 3, 7, 35, and 91 days). Crushed samples of a relatively simple Li-Na-Ca-K-Al-B-Si glass were reacted in the presence of a relatively high ionic strength fluid, to which various alteration phases (analcime, adularia, chabazite, or Na-montmorillonite) were added as “seed-crystals”. The release of boron and lithium were used to monitor the corrosion rate of the glass. In general, corrosion rates varied only slightly between the tests with different seed-crystals types. Boron and lithium contents in tests with analcime or adularia were slightly higher than tests with Na-montmorillonite or chabazite present. Silicon concentrations did not display any consistent variation over the testing interval, remaining relatively similar to the starting leachant value of 3.5 × 10−2 M. The concentration of aluminum, however, decreased significantly during the first 35 days of testing and could be inversely correlated to boron and lithium concentrations. The concentration of aluminum then increased between 35 and 91 days, whereas boron and lithium concentrations remained relatively static. The noted correlation between aluminum and boron (or lithium) suggests a coupling of the rate of glass corrosion with aluminum concentration.
Glassy slags (vitro-ceramics) are glass-crystal composites, and they are composed of various meta... more Glassy slags (vitro-ceramics) are glass-crystal composites, and they are composed of various metal oxide crystalline phases embedded in an aluminosilicate glass matrix. Glassy slags are developed to complement homogenous glass waste forms in implementing Minimum Additive Waste Stabilization (MAWS). Glassy slags with compositions developed in crucible melts at Argonne National Laboratory (ANL) were successfully produced in a bench-scale Retech plasma centrifugal furnace (PCF) by MSE, Inc. Detailed examinations of these materials showed that the crucible melts and the PCF produced similar glass and crystalline phases. The two sets of glassy slags exhibited similar chemical durability in terms of normaliied releases of their major components. The slags produced in the PCF furnace using metals were usually less oxidized, although this had no effect on the corrosion behavior of the major components of the slags. However, the normalized release rate of cerium was initially lower for the PCF slags. This difference diminished with time as the redox states of the metal oxides in slags began to be controlled by exposure to air in the tests. Thus, the difference in cerium release due to the differences in slag redox state may be transitory. The cerium solubility is a complex function of redox state and solution pH and Eh.
In an oxidizing environment, such as the proposed repository at Yucca Mountain (YM), rapid altera... more In an oxidizing environment, such as the proposed repository at Yucca Mountain (YM), rapid alteration rates are expected for spent nuclear fuel. Laboratory-scale simulations demonstrate that the dominant alteration products under YM repository conditions will be uranyl phases. There is an inadequate database to relate the effects of alteration products to the release of radionuclides, although this information is essential for providing realistic radionuclide-release estimates. It is likely that many radionuclides contained in spent fuel will be incorporated into alteration products with a potentially profound impact on the future mobility of radionuclides in the repository. Our objective is to characterize the incorporation of radionuclides into U(VI) alteration products by synthesizing uranyl phases doped with radionuclides, appropriate surrogate elements, or non-radioactive isotopes, followed by detailed phase characterization by diffraction and spectroscopic techniques. This research will permit a more realistic estimate of the release rates of radionuclides from the repository's near-field environment. RESEARCH PROGRESS AND IMPLICATIONS This report summarizes work after 20 months of a 36-month project. Our work involves several components: (1) structural characterization of the U phases that form due to the alteration of spent nuclear fuel, (2) theoretical predictions of incorporation mechanisms of radionuclides into U phases, (3) synthesis of radionuclide-bearing U phases to substantiate theoretical predictions, (4) investigations of ion exchange of radionuclides with U phases. These components, taken together, provide an enhanced understanding of the impact of U phases on the release of radionuclides during the corrosion of spent nuclear fuel.
Preliminary geology of the Proffit Mountain flood scour, Reynolds County, Missouri
From Precambrian Rift Volcanoes to the Mississippian Shelf Margin: Geological Field Excursions in the Ozark Mountains, 2010
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Papers by David Wronkiewicz