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Sample records for situ uranium stabilization

  1. In situ uranium stabilization by microbial metabolites

    International Nuclear Information System (INIS)

    Turick, Charles E.; Knox, Anna S.; Leverette, Chad L.; Kritzas, Yianne G.

    2008-01-01

    Microbial melanin production by autochthonous bacteria was explored in this study as a means to increase U immobilization in U contaminated soil. This article demonstrates the application of bacterial physiology and soil ecology for enhanced U immobilization in order to develop an in situ, U bio-immobilization technology. We have demonstrated microbial production of a metal chelating biopolymer, pyomelanin, in U contaminated soil from the Tims Branch area of the Department of Energy (DOE), Savannah River Site (SRS), South Carolina, as a result of tyrosine amendments. Bacterial densities of pyomelanin producers were >10 6 cells per g wet soil. Pyomelanin demonstrated U complexing and mineral binding capacities at pH 4 and 7. In laboratory studies, in the presence of goethite or illite, pyomelanin enhanced U sequestration by these minerals. Tyrosine amended soils in a field test demonstrated increased U sequestration capacity following pyomelanin production up to 13 months after tyrosine treatments

  2. IN SITU URANIUM STABILIZATION BY MICROBIAL METABOLITES

    Energy Technology Data Exchange (ETDEWEB)

    Turick, C; Anna Knox, A; Chad L Leverette,C; Yianne Kritzas, Y

    2006-11-29

    Soil contaminated with U was the focus of this study in order to develop in-situ, U bio-immobilization technology. We have demonstrated microbial production of a metal chelating biopolymer, pyomelanin, in U contaminated soil from the Tims Branch area of the Department of Energy (DOE) Savannah River Site (SRS) as a result of tyrosine amendments. Bacterial densities of pyomelanin producers were >106 cells/g wet soil. Pyomelanin demonstrated U chelating and mineral binding capacities at pH 4 and 7. In laboratory studies, in the presence of goethite or illite, pyomelanin enhanced U sequestration by these minerals. Tyrosine amended soils in field tests demonstrated increased U sequestration capacity following pyomelanin production up to 13 months after tyrosine treatments.

  3. In Situ Community Control of the Stability of Bioreduced Uranium

    International Nuclear Information System (INIS)

    White, David C.

    2006-01-01

    The overall objective of this research is to understand the mechanisms for maintenance of bio-reduced uranium in an aerobic to microaerophylic aquifer under actual field conditions after electron donor addition for biostimulation has ended. Primary Objectives: (1) Determine the relative importance of microbial communities and/or chemical and physical environments mediating uranium reduction/oxidation after cessation of donor addition in an aerobic aquifer. (2) Determine, after cessation of donor addition, the linkages between microbial functions and abiotic processes mediating. Initial Hypotheses: (1) The typical bio-reduced subsurface environments that maintain U(VI) reduction rates after biostimulation contain limited amounts of oxidized iron on mineral surfaces. Therefore, the non sulfate-reducing dissimilatory iron reducing bacteria will move to more conducive areas or be out-competed by more versatile microbes. (2) Microbes capable of sulfate reduction play an important role in the post-treatment maintenance of bio-reduced uranium because these bacteria either directly reduce U(VI) or generate H2S, and/or FeS0.9 which act as oxygen sinks maintaining U(IV) in a reduced state. (3) The presence of bioprecipitated amorphous FeS0.9 in sediments will maintain low U(IV) reoxidation rates under conditions of low biomass, but FeS0.9 by itself is not sufficient to remove U(VI) from groundwater by abiotic reduction. FIELD SCALE EXPERIMENTS: Field-scale electron donor amendment experiments were conducted in 2002, 2003, and 2004 at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site in Rifle, Colorado

  4. In Situ Microbial Community Control of the Stability of Bio-reduced Uranium

    International Nuclear Information System (INIS)

    Baldwin, Brett R.; Peacock, Aaron D.; Resch, Charles T.; Arntzen, Evan; Smithgall, Amanda N.; Pfiffner, Susan; Gan, M.; McKinley, James P.; Long, Philip E.; White, David C.

    2008-01-01

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is more soluble and thus more mobile. Field experiments at the Old Rifle UMTRA site have demonstrated that biostimulation by electron donor addition (acetate) promotes biological U(VI) reduction (2). However, U(VI) reduction is reversible and oxidative dissolution of precipitated U(IV) after the cessation of electron donor addition remains a critical issue for the application of biostimulation as a treatment technology. Despite the potential for oxidative dissolution, field experiments at the Old Rifle site have shown that rapid reoxidation of bio-reduced uranium does not occur and U(VI) concentrations can remain at approximately 20% of background levels for more than one year. The extent of post-amendment U(VI) removal and the maintenance of bioreduced uranium may result from many factors including U(VI) sorption to iron-containing mineral phases, generation of H2S or FeS0.9, or the preferential sorption of U(VI) by microbial cells or biopolymers, but the processes controlling the reduction and in situ reoxidation rates are not known. To investigate the role of microbial community composition in the maintenance of bioreduced uranium, in-well sediment incubators (ISIs) were developed allowing field deployment of amended and native sediments during on-going experiments at the site. Field deployment of the ISIs allows expedient interrogation of microbial community response to field environmental perturbations and varying geochemical conditions.

  5. In Situ Microbial Community Control of the Stability of Bio-reduced Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, Brett, R.; Peacock, Aaron, D.; Resch, Charles, T.; Arntzen, Evan; Smithgall, Amanda, N.; Pfiffner, Susan; Gan, M.; McKinley, James, P.; Long, Philip, E.; White, David, C.

    2008-03-28

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is more soluble and thus more mobile. Field experiments at the Old Rifle UMTRA site have demonstrated that biostimulation by electron donor addition (acetate) promotes biological U(VI) reduction (2). However, U(VI) reduction is reversible and oxidative dissolution of precipitated U(IV) after the cessation of electron donor addition remains a critical issue for the application of biostimulation as a treatment technology. Despite the potential for oxidative dissolution, field experiments at the Old Rifle site have shown that rapid reoxidation of bio-reduced uranium does not occur and U(VI) concentrations can remain at approximately 20% of background levels for more than one year. The extent of post-amendment U(VI) removal and the maintenance of bioreduced uranium may result from many factors including U(VI) sorption to iron-containing mineral phases, generation of H2S or FeS0.9, or the preferential sorption of U(VI) by microbial cells or biopolymers, but the processes controlling the reduction and in situ reoxidation rates are not known. To investigate the role of microbial community composition in the maintenance of bioreduced uranium, in-well sediment incubators (ISIs) were developed allowing field deployment of amended and native sediments during on-going experiments at the site. Field deployment of the ISIs allows expedient interrogation of microbial community response to field environmental perturbations and varying geochemical conditions.

  6. Theoretical stability assessment of uranyl phosphates and apatites: Selection of amendments for in situ remediation of uranium

    International Nuclear Information System (INIS)

    Raicevic, S.; Wright, J.V.; Veljkovic, V.; Conca, J.L.

    2006-01-01

    Addition of an amendment or reagent to soil/sediment is a technique that can decrease mobility and reduce bioavailability of uranium (U) and other heavy metals in the contaminated site. According to data from literature and results obtained in field studies, the general mineral class of apatites was selected as a most promising amendment for in situ immobilization/remediation of U. In this work we presented theoretical assessment of stability of U(VI) in four apatite systems (hydroxyapatite (HAP), North Carolina Apatite (NCA), Lisina Apatite (LA), and Apatite II) in order to determine an optimal apatite soil amendment which could be used for in situ remediation of uranium. In this analysis we used a theoretical criterion which is based on calculation of the ion-ion interaction potential, representing the main term of the cohesive energy of the matrix/pollutant system. The presented results of this analysis indicate (i) that the mechanism of immobilization of U by natural apatites depends on their chemical composition and (ii) that all analyzed apatites represent, from the point of view of stability, promising materials which could be used in field remediation of U-contaminated sites

  7. In situ leaching of uranium

    International Nuclear Information System (INIS)

    Martin, B.

    1980-01-01

    A process is described for the in-situ leaching of uranium-containing ores employing an acidic leach liquor containing peroxymonosulphuric acid. Preferably, additionally, sulphuric acid is present in the leach liquor. (author)

  8. In situ Microbial Community Control of the Stability of Bio-Reduced Uranium

    International Nuclear Information System (INIS)

    Long, Phillip E.; McKinley, James P.; White, David C.

    2006-01-01

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is soluble and thus mobile compared to U(IV). Previous work at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site demonstrated that biostimulation by acetate injection promoted growth of Geobacteraceae and stimulated the microbial reduction of U(VI) to less soluble U(IV) (1, 4). Despite the potential for oxidative dissolution of bio-reduced U(IV), field experiments at the Old Rifle site show that although the rate of U(VI) reduction decreases following the on-set of sulfate reduction, U(VI) reduction continues even following the cessation of acetate injection (1, 4). However, U(VI) reduction is reversible and the basis for the observed maintenance of U(VI) reduction post-stimulation is a critical but as yet unresolved issue for the application of biostimulation as a treatment technology. The continued U(VI) reduction and the maintenance of reduced U(IV) may result from many factors including U(VI) reduction by sulfate reducing bacteria (SRB), generation of H2S or FeS0.9 which serves as an oxygen sink, or the preferential sorption of U(VI) by microbial cells or biopolymers. The overall goal of the project is to develop an understanding of the mechanisms for the maintenance of bio-reduced uranium in an aerobic aquifer under field conditions following the cessation of electron donor addition

  9. Uranium mill tailings stabilization

    International Nuclear Information System (INIS)

    Hartley, J.N.; Koehmstedt, P.L.; Esterl, D.J.; Freeman, H.D.

    1980-02-01

    Uranium mill tailings pose a potential radiation health hazard to the public. Therefore, stabilization or disposal of these tailings in a safe and environmentally sound way is needed to minimize radon exhalation and other environmental hazards. One of the most promising concepts for stabilizing U tailings is the use of asphalt emulsion to contain radon and other hazardous materials within uranium tailings. This approach is being investigated at the Pacific Northwest Laboratory. Results of these studies indicate that a radon flux reduction of greater than 99% can be obtained using either a poured-on/sprayed-on seal (3.0 to 7.0 mm thick) or an admixture seal (2.5 to 12.7 cm thick) containing about 18 wt % residual asphalt. A field test was carried out in June 1979 at the Grand Junction tailings pile in order to demonstrate the sealing process. A reduction in radon flux ranging from 4.5 to greater than 99% (76% average) was achieved using a 15.2-cm (6-in.) admix seal with a sprayed-on top coat. A hydrostatic stabilizer was used to apply the admix. Following compaction, a spray coat seal was applied over the admix as the final step in construction of a radon seal. Overburden was applied to provide a protective soil layer over the seal. Included in part of the overburden was a herbicide to prevent root penetration

  10. Technology assessment of in situ uranium mining

    International Nuclear Information System (INIS)

    Cowan, C.E.

    1981-01-01

    The objective of the PNL portion of the Technology Assessment project is to provide a description of the current in situ uranium mining technology; to evaluate, based on available data, the environmental impacts and, in a limited fashion, the health effects; and to explore the impediments to development and deployment of the in situ uranium mining technology

  11. Inherently safe in situ uranium recovery

    Science.gov (United States)

    Krumhansl, James L; Brady, Patrick V

    2014-04-29

    An in situ recovery of uranium operation involves circulating reactive fluids through an underground uranium deposit. These fluids contain chemicals that dissolve the uranium ore. Uranium is recovered from the fluids after they are pumped back to the surface. Chemicals used to accomplish this include complexing agents that are organic, readily degradable, and/or have a predictable lifetime in an aquifer. Efficiency is increased through development of organic agents targeted to complexing tetravalent uranium rather than hexavalent uranium. The operation provides for in situ immobilization of some oxy-anion pollutants under oxidizing conditions as well as reducing conditions. The operation also artificially reestablishes reducing conditions on the aquifer after uranium recovery is completed. With the ability to have the impacted aquifer reliably remediated, the uranium recovery operation can be considered inherently safe.

  12. Inherently safe in situ uranium recovery

    International Nuclear Information System (INIS)

    Krumhansl, James Lee; Beauheim, Richard Louis; Brady, Patrick Vane; Arnold, Bill Walter; Kanney, Joseph F.; McKenna, Sean Andrew

    2009-01-01

    Expansion of uranium mining in the United States is a concern to some environmental groups and sovereign Native American Nations. An approach which may alleviate some problems is to develop inherently safe in situ uranium recovery ('ISR') technologies. Current ISR technology relies on chemical extraction of trace levels of uranium from aquifers that, once mined, can still contain dissolved uranium and other trace metals that are a health concern. Existing ISR operations are few in number; however, high uranium prices are driving the industry to consider expanding operations nation-wide. Environmental concerns and enforcement of the new 30 ppb uranium drinking water standard may make opening new mining operations more difficult and costly. Here we propose a technological fix: the development of inherently safe in situ recovery (ISISR) methods. The four central features of an ISISR approach are: (1) New 'green' leachants that break down predictably in the subsurface, leaving uranium, and associated trace metals, in an immobile form; (2) Post-leachant uranium/metals-immobilizing washes that provide a backup decontamination process; (3) An optimized well-field design that increases uranium recovery efficiency and minimizes excursions of contaminated water; and (4) A combined hydrologic/geochemical protocol for designing low-cost post-extraction long-term monitoring. ISISR would bring larger amounts of uranium to the surface, leave fewer toxic metals in the aquifer, and cost less to monitor safely - thus providing a 'win-win-win' solution to all stakeholders.

  13. In situ remediation of uranium contaminated groundwater

    International Nuclear Information System (INIS)

    Dwyer, B.P.; Marozas, D.C.

    1997-01-01

    In an effort to develop cost-efficient techniques for remediating uranium contaminated groundwater at DOE Uranium Mill Tailing Remedial Action (UMTRA) sites nationwide, Sandia National Laboratories (SNL) deployed a pilot scale research project at an UMTRA site in Durango, CO. Implementation included design, construction, and subsequent monitoring of an in situ passive reactive barrier to remove Uranium from the tailings pile effluent. A reactive subsurface barrier is produced by emplacing a reactant material (in this experiment various forms of metallic iron) in the flow path of the contaminated groundwater. Conceptually the iron media reduces and/or adsorbs uranium in situ to acceptable regulatory levels. In addition, other metals such as Se, Mo, and As have been removed by the reductive/adsorptive process. The primary objective of the experiment was to eliminate the need for surface treatment of tailing pile effluent. Experimental design, and laboratory and field results are discussed with regard to other potential contaminated groundwater treatment applications

  14. In-situ uranium leaching

    International Nuclear Information System (INIS)

    Dotson, B.J.

    1986-01-01

    This invention provides a method for improving the recovery of mineral values from ore bodies subjected to in-situ leaching by controlling the flow behaviour of the leaching solution. In particular, the invention relates to an in-situ leaching operation employing a foam for mobility control of the leaching solution. A foam bank is either introduced into the ore bed or developed in-situ in the ore bed. The foam then becomes a diverting agent forcing the leaching fluid through the previously non-contacted regions of the deposit

  15. Uranium speciation and stability after reductive immobilization in aquifer sediments

    Science.gov (United States)

    Sharp, Jonathan O.; Lezama-Pacheco, Juan S.; Schofield, Eleanor J.; Junier, Pilar; Ulrich, Kai-Uwe; Chinni, Satya; Veeramani, Harish; Margot-Roquier, Camille; Webb, Samuel M.; Tebo, Bradley M.; Giammar, Daniel E.; Bargar, John R.; Bernier-Latmani, Rizlan

    2011-11-01

    It has generally been assumed that the bioreduction of hexavalent uranium in groundwater systems will result in the precipitation of immobile uraninite (UO 2). In order to explore the form and stability of uranium immobilized under these conditions, we introduced lactate (15 mM for 3 months) into flow-through columns containing sediments derived from a former uranium-processing site at Old Rifle, CO. This resulted in metal-reducing conditions as evidenced by concurrent uranium uptake and iron release. Despite initial augmentation with Shewanella oneidensis, bacteria belonging to the phylum Firmicutes dominated the biostimulated columns. The immobilization of uranium (˜1 mmol U per kg sediment) enabled analysis by X-ray absorption spectroscopy (XAS). Tetravalent uranium associated with these sediments did not have spectroscopic signatures representative of U-U shells or crystalline UO 2. Analysis by microfocused XAS revealed concentrated micrometer regions of solid U(IV) that had spectroscopic signatures consistent with bulk analyses and a poor proximal correlation (μm scale resolution) between U and Fe. A plausible explanation, supported by biogeochemical conditions and spectral interpretations, is uranium association with phosphoryl moieties found in biomass; hence implicating direct enzymatic uranium reduction. After the immobilization phase, two months of in situ exposure to oxic influent did not result in substantial uranium remobilization. Ex situ flow-through experiments demonstrated more rapid uranium mobilization than observed in column oxidation studies and indicated that sediment-associated U(IV) is more mobile than biogenic UO 2. This work suggests that in situ uranium bioimmobilization studies and subsurface modeling parameters should be expanded to account for non-uraninite U(IV) species associated with biomass.

  16. Process for in-situ leaching of uranium

    International Nuclear Information System (INIS)

    Espenscheid, W.F.; Yan, F.Y.

    1983-01-01

    The present invention relates to the recovery of uranium from subterranean ore deposits, and more particularly to an in-situ leaching operation employing an aqueous solution of sulfuric acid and carbon dioxide as the lixiviant. Uranium is solubilized in the lixiviant as it traverses the subterranean uranium deposit. The lixiviant is subsequently recovered and treated to remove the uranium

  17. Radiological aspects of in situ uranium recovery

    International Nuclear Information System (INIS)

    BROWN, STEVEN H.

    2007-01-01

    In the last few years, there has been a significant increase in the demand for Uranium as historical inventories have been consumed and new reactor orders are being placed. Numerous mineralized properties around the world are being evaluated for Uranium recovery and new mining / milling projects are being evaluated and developed. Ore bodies which are considered uneconomical to mine by conventional methods such as tunneling or open pits, can be candidates for non-conventional recovery techniques, involving considerably less capital expenditure. Technologies such as Uranium in situ leaching in situ recovery (ISL / ISR), have enabled commercial scale mining and milling of relatively small ore pockets of lower grade, and may make a significant contribution to overall world wide uranium supplies over the next ten years. Commercial size solution mining production facilities have operated in the US since 1975. Solution mining involves the pumping of groundwater, fortified with oxidizing and complexing agents into an ore body, solubilizing the uranium in situ, and then pumping the solutions to the surface where they are fed to a processing plant. Processing involves ion exchange and may also include precipitation, drying or calcining and packaging operations depending on facility specifics. This paper presents an overview of the ISR process and the health physics monitoring programs developed at a number of commercial scale ISL / ISR Uranium recovery and production facilities as a result of the radiological character of these processes. Although many radiological aspects of the process are similar to that of conventional mills, conventional-type tailings as such are not generated. However, liquid and solid byproduct materials may be generated and impounded. The quantity and radiological character of these by products are related to facility specifics. Some special monitoring considerations are presented which are required due to the manner in which Radon gas is evolved in

  18. Novel Sensor for the In Situ Measurement of Uranium Fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Hatfield, Kirk [Univ. of Florida, Gainesville, FL (United States)

    2015-02-10

    The goal of this project was to develop a sensor that incorporates the field-tested concepts of the passive flux meter to provide direct in situ measures of flux for uranium and groundwater in porous media. Measurable contaminant fluxes [J] are essentially the product of concentration [C] and groundwater flux or specific discharge [q ]. The sensor measures [J] and [q] by changes in contaminant and tracer amounts respectively on a sorbent. By using measurement rather than inference from static parameters, the sensor can directly advance conceptual and computational models for field scale simulations. The sensor was deployed in conjunction with DOE in obtaining field-scale quantification of subsurface processes affecting uranium transport (e.g., advection) and transformation (e.g., uranium attenuation) at the Rifle IFRC Site in Rifle, Colorado. Project results have expanded our current understanding of how field-scale spatial variations in fluxes of uranium, groundwater and salient electron donor/acceptors are coupled to spatial variations in measured microbial biomass/community composition, effective field-scale uranium mass balances, attenuation, and stability. The coupling between uranium, various nutrients and micro flora can be used to estimate field-scale rates of uranium attenuation and field-scale transitions in microbial communities. This research focuses on uranium (VI), but the sensor principles and design are applicable to field-scale fate and transport of other radionuclides. Laboratory studies focused on sorbent selection and calibration, along with sensor development and validation under controlled conditions. Field studies were conducted at the Rifle IFRC Site in Rifle, Colorado. These studies were closely coordinated with existing SBR (formerly ERSP) projects to complement data collection. Small field tests were conducted during the first two years that focused on evaluating field-scale deployment procedures and validating sensor performance under

  19. Study of lixiviant damage of a sandstone deposit during in-situ leaching of uranium

    International Nuclear Information System (INIS)

    Liao Wensheng; Wang Limin; Jiang Yan; Jiang Guoping; Tan Yahui

    2014-01-01

    The permeability of sandstone deposit is a key factor for economical uranium recovery during in-situ leaching uranium. Low permeability sandstone uranium deposits behave low push-pull capacity, and show formation damage in leaching operations. It is important to study formation damage of permeability, therefore, and to stabilize even improve the push-pull power of drillholes during in-situ leaching. In this paper, formation damage caused by lixiviants was investigated based on a low permeability sandstone uranium deposit. The resulted showed that, under the conditions of in-situ leaching, the salinity of leaching fluid has no harm to formation permeability, on the contrary, the increment of salinity of lixiviant during in-situ leaching improve the permeability of the deposit. The alkalinity, hydrogen peroxide and productivity of the lixiviant cause no significant formation damage. But the fine particles in the lixiviant shows formation damage significantly, and the quantity of the particles should be controlled during production. (authors)

  20. Manual of acid in situ leach uranium mining technology

    International Nuclear Information System (INIS)

    2001-08-01

    In situ leaching (ISL) technology recovers uranium using two alternative chemical leaching systems - acid and alkaline. This report brings together information from several technical disciplines that are an essential part of ISL technology. They include uranium geology, geohydrology, chemistry as well as reservoir engineering and process engineering. This report provides an extensive description of acid ISL uranium mining technology

  1. Manual of acid in situ leach uranium mining technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-08-01

    In situ leaching (ISL) technology recovers uranium using two alternative chemical leaching systems - acid and alkaline. This report brings together information from several technical disciplines that are an essential part of ISL technology. They include uranium geology, geohydrology, chemistry as well as reservoir engineering and process engineering. This report provides an extensive description of acid ISL uranium mining technology.

  2. Process for the in-situ leaching of uranium

    International Nuclear Information System (INIS)

    Habib, E.T.; Vogt, T.C.

    1982-01-01

    Process for the in-situ leaching of uranium employing an alkaline lixiviant and an alkali metal or alkaline earth metal hypochlorite as an oxidizing agent. The use of the hypochlorite oxidant results in significantly higher uranium recoveries and leaching rates than those attained by the use of conventional oxidants. The invention is particularly suitable for use in subterranean deposits in which the uranium mineral is associated with carbonaceous material which retards access to the uranium by the lixiviant

  3. 77 FR 33782 - License Amendment To Construct and Operate New In Situ Leach Uranium Recovery Facility; Uranium...

    Science.gov (United States)

    2012-06-07

    ... and Operate New In Situ Leach Uranium Recovery Facility; Uranium One Americas; Ludeman AGENCY: Nuclear... provided the first time that a document is referenced. The Ludeman facility In Situ Leach Uranium Recovery... request to amend Source Material License SUA-1341 to construct and operate a new in situ leach uranium...

  4. 300 Area Uranium Stabilization Through Polyphosphate Injection: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Vermeul, Vincent R.; Bjornstad, Bruce N.; Fritz, Brad G.; Fruchter, Jonathan S.; Mackley, Rob D.; Newcomer, Darrell R.; Mendoza, Donaldo P.; Rockhold, Mark L.; Wellman, Dawn M.; Williams, Mark D.

    2009-06-30

    amendment arrival response data indicate some degree of overlap between the reactive species and thus potential for the formation of calcium-phosphate mineral phases (i.e., apatite formation), the efficiency of this treatment approach was relatively poor. In general, uranium performance monitoring results support the hypothesis that limited long-term treatment capacity (i.e., apatite formation) was established during the injection test. Two separate overarching issues affect the efficacy of apatite remediation for uranium sequestration within the 300 Area: 1) the efficacy of apatite for sequestering uranium under the present geochemical and hydrodynamic conditions, and 2) the formation and emplacement of apatite via polyphosphate technology. In addition, the long-term stability of uranium sequestered via apatite is dependent on the chemical speciation of uranium, surface speciation of apatite, and the mechanism of retention, which is highly susceptible to dynamic geochemical conditions. It was expected that uranium sequestration in the presence of hydroxyapatite would occur by sorption and/or surface complexation until all surface sites have been depleted, but that the high carbonate concentrations in the 300 Area would act to inhibit the transformation of sorbed uranium to chernikovite and/or autunite. Adsorption of uranium by apatite was never considered a viable approach for in situ uranium sequestration in and of itself, because by definition, this is a reversible reaction. The efficacy of uranium sequestration by apatite assumes that the adsorbed uranium would subsequently convert to autunite, or other stable uranium phases. Because this appears to not be the case in the 300 Area aquifer, even in locations near the river, apatite may have limited efficacy for the retention and long-term immobilization of uranium at the 300 Area site..

  5. In situ leaching of uranium: Technical, environmental and economic aspects

    International Nuclear Information System (INIS)

    1989-01-01

    Within the framework of its activities in nuclear raw materials the International Atomic Energy Agency has convened a series of meetings to discuss various aspects of uranium ore processing technology, recovery of uranium from non-conventional resources and development of projects for the production of uranium concentrates including economic aspects. As part of this continuing effort to discuss and document important aspects of uranium production the IAEA convened a Technical Committee Meeting on Technical, Economic and Environmental Aspects of In-Situ Leaching. Although the use of this technique is limited by geological and economic constraints, it has a significant potential to produce uranium at competitive prices. This is especially important in the current uranium market which is mainly characterised by large inventories, excess production capability and low prices. This situation is not expected to last indefinitely but it is unlikely to change drastically in the next ten years or so. This Technical Committee Meeting was held in Vienna from 3 to 6 November 1987 with the attendance of 24 participants from 12 countries. Eight papers were presented. Technical sessions covered in-situ mining research, environmental and licensing aspects and restoration of leached orebodies; the technological status of in-situ leaching, the current status and future prospects of in-situ leaching of uranium in Member States, general aspects of planning and implementation of in-situ projects and the economics of in-situ leaching. Refs, figs and tabs

  6. Cap stabilization for reclaimed uranium sites

    International Nuclear Information System (INIS)

    Abt, S.R.; Nelson, J.D.; Johnson, T.L.; Hawkins, E.F.

    1989-01-01

    The reclamation and stabilization of uranium-mill tailings sites requires engineering designs to protect against the disruption of tailings and the potential release of radioactive materials. The reclamation design is to be effective for 200-1000 years. This paper presents recently developed or refined techniques and methodologies used to evaluate uranium-tailings-reclamation plans designed to provide long-term stability against failure modes. Specific cap-design aspects presented include design flood selection, influence of fluvial geomorphology on site stabilization, stable slope prediction, slope stabilization using riprap, and riprap selection relative to rock quality and durability. Design relationships are presented for estimating flow through riprap, sizing riprap, and estimating riprap flow resistance for overtopping conditions. Guidelines for riprap-layer thickness and gradation are presented. A riprap-rating procedure for estimating rock quality and durability is also presented

  7. Some implications of in situ uranium mining technology development

    International Nuclear Information System (INIS)

    Cowan, C.E.; Parkhurst, M.A.; Cole, R.J.; Keller, D.; Mellinger, P.J.; Wallace, R.W.

    1980-09-01

    A technology assessment was initiated in March 1979 of the in-situ uranium mining technology. This report explores the impediments to development and deployment of this technology and evaluates the environmental impacts of a generic in-situ facility. The report is divided into the following sections: introduction, technology description, physical environment, institutional and socioeconomic environment, impact assessment, impediments, and conclusions

  8. Solution (in situ leach) mining of uranium: an overview

    International Nuclear Information System (INIS)

    Kuhaida, A.J. Jr.; Kelly, M.J.

    1978-01-01

    Increases in the demand for and price of uranium have made in-situ mining an attractive alternative to the open-pit and underground U mining methods. Up to 50% of the known ore-bearing sandstone in the western U.S. can be mined using the in-situ mining method. In-situ mining also offers a significant environmental advantage. Restoration of the contaminated groundwater is discussed

  9. Aquifer restoration techniques for in-situ leach uranium mines

    International Nuclear Information System (INIS)

    Deutsch, W.J.; Bell, N.E.; Mercer, B.W.; Serne, R.J.; Shade, J.W.; Tweeton, D.R.

    1984-02-01

    In-situ leach uranium mines and pilot-scale test facilities are currently operating in the states of Wyoming, Texas, New Mexico and Colorado. This report summarizes the technical considerations involved in restoring a leached ore zone and its aquifer to the required level. Background information is provided on the geology and geochemistry of mineralized roll-front deposits and on the leaching techniques used to extract the uranium. 13 references, 13 figures, 4 tables

  10. Chattanooga shale: uranium recovery by in situ processing

    International Nuclear Information System (INIS)

    Jackson, D.D.

    1977-01-01

    The increasing demand for uranium as reactor fuel requires the addition of sizable new domestic reserves. One of the largest potential sources of low-grade uranium ore is the Chattanooga shale--a formation in Tennessee and neighboring states that has not been mined conventionally because it is expensive and environmentally disadvantageous to do so. An in situ process, on the other hand, might be used to extract uranium from this formation without the attendant problems of conventional mining. We have suggested developing such a process, in which fracturing, retorting, and pressure leaching might be used to extract the uranium. The potential advantages of such a process are that capital investment would be reduced, handling and disposing of the ore would be avoided, and leaching reagents would be self-generated from air and water. If successful, the cost reductions from these factors could make the uranium produced competitive with that from other sources, and substantially increase domestic reserves. A technical program to evaluate the processing problems has been outlined and a conceptual model of the extraction process has been developed. Preliminary cost estimates have been made, although it is recognized that their validity depends on how successfully the various processing steps are carried out. In view of the preliminary nature of this survey (and our growing need for uranium), we have urged a more detailed study on the feasibility of in situ methods for extracting uranium from the Chattanooga shale

  11. Treatability Test Plan for 300 Area Uranium Stabilization through Polyphosphate Injection

    Energy Technology Data Exchange (ETDEWEB)

    Vermeul, Vincent R.; Williams, Mark D.; Fritz, Brad G.; Mackley, Rob D.; Mendoza, Donaldo P.; Newcomer, Darrell R.; Rockhold, Mark L.; Williams, Bruce A.; Wellman, Dawn M.

    2007-06-01

    The U.S. Department of Energy has initiated a study into possible options for stabilizing uranium at the 300 Area using polyphosphate injection. As part of this effort, PNNL will perform bench- and field-scale treatability testing designed to evaluate the efficacy of using polyphosphate injections to reduced uranium concentrations in the groundwater to meet drinking water standards (30 ug/L) in situ. This technology works by forming phosphate minerals (autunite and apatite) in the aquifer that directly sequester the existing aqueous uranium in autunite minerals and precipitates apatite minerals for sorption and long term treatment of uranium migrating into the treatment zone, thus reducing current and future aqueous uranium concentrations. Polyphosphate injection was selected for testing based on technology screening as part of the 300-FF-5 Phase III Feasibility Study for treatment of uranium in the 300-Area.

  12. Treatability Test Plan for 300 Area Uranium Stabilization through Polyphosphate Injection

    International Nuclear Information System (INIS)

    Vermeul, Vince R.; Williams, M. D.; Fritz, Brad G.; Mackley, Rob D.; Mendoza, Donaldo P.; Newcomer, Darrell R.; Rockhold, Mark L.; Williams, Bruce A.; Wellman, Dawn M.

    2007-01-01

    The U.S. Department of Energy has initiated a study into possible options for stabilizing uranium at the 300 Area using polyphosphate injection. As part of this effort, PNNL will perform bench- and field-scale treatability testing designed to evaluate the efficacy of using polyphosphate injections to reduced uranium concentrations in the groundwater to meet drinking water standards (30 (micro)g/L) in situ. This technology works by forming phosphate minerals (autunite and apatite) in the aquifer that directly sequester the existing aqueous uranium in autunite minerals and precipitates apatite minerals for sorption and long term treatment of uranium migrating into the treatment zone, thus reducing current and future aqueous uranium concentrations. Polyphosphate injection was selected for testing based on technology screening as part of the 300-FF-5 Phase III Feasibility Study for treatment of uranium in the 300-Area

  13. Magnesium bicarbonate as an in situ uranium lixiviant

    International Nuclear Information System (INIS)

    Sibert, J.W.

    1984-01-01

    In the subsurface solution mining of mineral values, especially uranium, in situ, magnesium bicarbonate leaching solution is used instead of sodium, potassium and ammonium carbonate and bicarbonates. The magnesium bicarbonate solution is formed by combining carbon dioxide with magnesium oxide and water. The magnesium bicarbonate lixivant has four major advantages over prior art sodium, potassium and ammonium bicarbonates

  14. Evaluation and analysis of geological condition of in-situ fragmentation leaching uranium

    International Nuclear Information System (INIS)

    Yang Jianming; Tan Kaixuan; Huang Xiaonai

    2003-01-01

    The ore geological condition, hydrogeological condition, engineering geological condition and technological mineralogical character of in-situ fragmentation leaching uranium are analyzed, and it is considered that the implementation of in-situ fragmentation leaching uranium technology is decided by different geological factor. Previously prospecting and geological condition evaluation of uranium ore is based on traditional mining method. If in-situ fragmentation leaching uranium method is adopted, one must re-evaluate previously prospected deposits before they are mined, or one must evaluate new prospecting deposits according to geological conditions of in-situ fragmentation leaching uranium method. The feasibility evaluation method of uranium deposit by in-situ fragmentation leaching uranium put forward by B. N. Mociniets is introducd, and it is considered that B. N. Mociniets method has guidable significance for geological condition evaluation before uranium deposits are mined. A feasibility study is done by applying B. N. Mociniets method to a uranium deposit. (authors)

  15. Uranium speciation and stability after reductive immobilization in sediments.

    OpenAIRE

    Sharp J.O

    2011-01-01

    It has generally been assumed that the bioreduction of hexavalent uranium in groundwater systems will result in the precipitation of immobile uraninite (UO2). In order to explore the form and stability of uranium immobilized under these conditions we introduced lactate (15 mM for 3 months) into flow through columns containing sediments derived from a former uranium processing site at Old Rifle CO. This resulted in metal reducing conditions as evidenced by concurrent uranium uptake and iron re...

  16. Uranium speciation and stability after reductive immobilization in sediments

    OpenAIRE

    Sharp, Jonathan O.; Schofield, Eleanor J.; Lezama-Pacheco, Juan S.; Webb, Sam; Ulrich, Kai-Uwe; Blue, Lisa; Chinni, Satyavani; Veeramani, Harish; Junier, Pilar; Margot-Roquier, Camille; Suvorova Buffat, Elena; Tebo, Bradley M.; Giammar, Daniel E.; Bargar, John R.; Bernier-Latmani, Rizlan

    2011-01-01

    It has generally been assumed that the bioreduction of hexavalent uranium in groundwater systems will result in the precipitation of immobile uraninite (UO2). In order to explore the form and stability of uranium immobilized under these conditions, we introduced lactate (15 mM for 3 months) into flow-through columns containing sediments derived from a former uranium-processing site at Old Rifle, CO. This resulted in metal-reducing conditions as evidenced by concurrent uranium uptake and iron ...

  17. Best practice in situ recovery uranium mining in Australia

    International Nuclear Information System (INIS)

    Lambert, I.B.; McKay, A.D.; Carson, L.J.

    2010-01-01

    The Australian Government policy is to ensure that uranium mining, milling and rehabilitation is based on world best practice standards. A best practice guide for in situ recovery (ISR) uranium mining has been developed to communicate the Australian Government's expectations with a view to achieving greater certainty that ISR mining projects meet Australian Government policy and consistency in the assessment of ISR mine proposals within multiple government regulatory processes. The guide focuses on the main perceived risks; impacts on groundwaters, disposal of mining residues, and radiation protection. World best practice does not amount to a universal template for ISR mining because the characteristics of individual ore bodies determine the best practice. (author)

  18. Recovering uranium from coal in situ

    International Nuclear Information System (INIS)

    Terry, R.C.

    1978-01-01

    An underground carbonaceous deposit containing other mineral values is burned in situ. The underground hot zone is cooled down to temperature below the boiling point of a leachig solution. The leaching solution is percolated through the residial ash, with the pregnant solution recovered for separation of the mineral values in surface facilities

  19. Engineering feasibility analysis for in-situ stabilization of Canonsburg residues. [UMTRA project

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    The US Department of Energy is considering several methods for carrying out remedial actions in Canonsburg, Pennsylvania, at the site of an inactive uranium-processing mill. The main objective of this study is to determine the feasibility of in-situ stabilization as the remedial action. In-situ stabilization is an alternative to site decontamination and offsite disposal. The problems associated with offsite hauling of large quantities of contaminated material and with the location and development of a new disposal site could be avoided by the implementation of an in-situ stabilization concept. In addition, the in-situ approach would be more cost-effective than offsite disposal. This study will establish that a technically feasible and implementable in-situ stabilization concept can be developed that meets regulatory requirements and is cost effective. This study in no way commits the DOE to implement any specific actions described herein. 11 refs., 30 figs., 24 tabs.

  20. Engineering feasibility analysis for in-situ stabilization of Canonsburg residues

    International Nuclear Information System (INIS)

    1982-01-01

    The US Department of Energy is considering several methods for carrying out remedial actions in Canonsburg, Pennsylvania, at the site of an inactive uranium-processing mill. The main objective of this study is to determine the feasibility of in-situ stabilization as the remedial action. In-situ stabilization is an alternative to site decontamination and offsite disposal. The problems associated with offsite hauling of large quantities of contaminated material and with the location and development of a new disposal site could be avoided by the implementation of an in-situ stabilization concept. In addition, the in-situ approach would be more cost-effective than offsite disposal. This study will establish that a technically feasible and implementable in-situ stabilization concept can be developed that meets regulatory requirements and is cost effective. This study in no way commits the DOE to implement any specific actions described herein. 11 refs., 30 figs., 24 tabs

  1. In situ leaching of uranium in South Australia

    International Nuclear Information System (INIS)

    Matthews, D.

    1998-01-01

    The proposed two new uranium mines at Beverley and Honeymoon, South Australia plan to use the cheap but potentially polluting process of in situ leaching (ISL) and permission has already been given for experimental underground leaching at Beverley. The mining industry describes ISL as environmentally benign because, instead of excavating, a corrosive liquid such as sulphuric acid is used. The liquid, sometimes 10000 times more acid than the aquifer water, is pumped into the ground in order to leach out the uranium and the resulting solution is then pumped to the surface where the uranium is extracted. Because the groundwater is salty and radioactive, the mining companies regard it as useless, so its contamination by ISL is considered of no concern. Salty radioactive water can be purified or desalinated and such processes are commonly used by mining companies such as Western Mining Corporation at Roxby Downs. (author)

  2. Aluminum chloride restoration of in situ leached uranium ores

    International Nuclear Information System (INIS)

    Grant, D.C.; Burgman, M.A.

    1982-01-01

    During in situ uranium mining using ammonium bicarbonate lixiviant, the ammonium exchanges with cations on the ore's clay. After mining is complete, the ammonium may desorb into post-leach ground water. For the particular ore studied, other chemicals (i.e., uranium and selenium) which are mobilized during the leach process, have also been found in the post-leach ground water. Laboratory column tests, used to simulate the leaching process, have shown that aluminum chloride can rapidly remove ammonium from the ore and thus greatly reduce the subsequent ammonium leakage level into ground water. The aluminum chloride has also been found to reduce the leakage levels of uranium and selenium. In addition, the aluminum chloride treatment produces a rapid improvement in permeability

  3. The Honeymoon project: Australia's first in situ leach uranium project

    International Nuclear Information System (INIS)

    Ackland, M.C.

    1997-01-01

    The Honeymoon uranium deposit is one of several roll front uranium deposits in South Australia. It was discovered in 1971, the project developed in the 1970's, and was ready for demonstration of the In Situ Leaching (ISL) production techniques by January 1983, when the project was stopped, despite it having met the environmental approvals to proceed, due to the Australian Labour Party's 'three mines policy'. From 1983 until March 1996 the project was mothballed. In late 1996 Southern Cross Resources Inc. (SCRI) reached agreement with Mount Isa Mining (MIM) to purchase its uranium interests in Honeymoon, Goulds Dam and EL 2310 whilst simultaneously acquiring Sedimentary Holdings NL's interests in EL 2310. By April 1997 these interests were consolidated in SCRI's wholly owned subsidiary, Southern Cross Resources Australia Ply Ltd which is the operating company. Activities are presently underway to rehabilitate the existing treatment plant and continue the program that was outlined in the approved 1981 Honeymoon Environmental Impact Statement

  4. Restoration of uranium in-situ leaching sites

    International Nuclear Information System (INIS)

    Hill, A.D.; Silberberg, I.H.; Walsh, M.P.; Breland, W.M.; Humenick, M.J.; Schechter, R.S.

    1980-01-01

    Ammonium ions introduced into the formation during in-situ uranium leach mining must be removed by a restoration process. Ion exchange processes to strip sorbed ammonium cation from the clays have been modeled and studied experimentally. It is concluded that ammonium removal can be accomplished best by a high-ionic-strength flush. The migration of uncovered ammonium cation in groundwater also is studied. 19 refs

  5. Current status and prospects of uranium geology developments of foreign in-situ leachable sandstone type uranium deposits

    International Nuclear Information System (INIS)

    Wang Zhengbang

    2002-01-01

    Firstly, with emphasis on in-situ leachable sandstone-type uranium deposits, the prospecting history of uranium deposits worldwide and its scientific research development are generally reviewed in four steps, and their basic historical experience is also summarized. Secondly, based on the detailed description of current development status of uranium geology of foreign in-situ leachable sandstone-type uranium deposits the important strategic position of sandstone-type uranium deposits in overall uranium resources all-over-the-world and its classification, spatial-temporal distribution and regulation, and metallogenic condition of sandstone-type uranium deposits are analysed thoroughly in five aspects: techtonics, paleo-climate, hydrogeology, sedimentary facies and lithology, as well as uranium sources: Afterwards, evaluation principles of three type of hyper-genic, epigenetic infiltrated sandstone-type uranium deposits are summarized. Based on sandstone-type uranium deposits located two important countries: the United States and Russia, the current development status of prospecting technology for in-situ leachable sandstone-type uranium deposits in foreign countries is outlined. Finally, according to the prospects of supply-demand development of global uranium resources, the author points out seriously that Chinese uranium geology is faced with a severe challenge, and proposes directly four strategic measures that should be taken

  6. Technique for in situ leach simulation of uranium ores

    International Nuclear Information System (INIS)

    Grant, D.C.; Seidel, D.C.; Nichols, I.L.

    1985-01-01

    In situ uranium mining offers the advantages of minimal environmental disturbance, low capital and operating costs, and reduced mining development time. It is becoming an increasingly attractive mining method for the recovery of uranium from secondary ore deposits. In order to better understand the process, a laboratory technique was developed and used to study and simulate both the chemical and physical phenomena occurring in ore bodies during in situ leaching. The laboratory simulation technique has been used to determine effects of leaching variables on permeability, uranium recovery, and post-leach aquifer restoration. This report describes the simulation system and testing procedure in sufficient detail to allow the construction of the system, and to perform the desired leaching tests. With construction of such a system, in situ leaching of a given ore using various leach conditions can be evaluated relatively rapidly in the laboratory. Not only could optimum leach conditions be selected for existing ore bodies, but also exploitation of new ore bodies could be accelerated. 8 references, 8 figures, 2 tables

  7. Thermal stabilization of uranium mill tailings

    International Nuclear Information System (INIS)

    Dreesen, D.R.; Williams, J.M.; Cokal, E.J.

    1981-01-01

    The sintering of tailings at high temperatures (1200 0 C) has shown promise as a conditioning approach that greatly reduces the 222 Rn emanation of uranium mill tailings. The structure of thermally stabilized tailings has been appreciably altered producing a material that will have minimal management requirements and will be applicable to on-site processing and disposal. The mineralogy of untreated tailings is presented to define the structure of the original materials. Quartz predominates in most tailings samples; however, appreciable quantities of gypsum, clay, illite, or albites are found in some tailings. Samples from the Durango and Shiprock sites have plagioclase-type aluminosilicates and non-aluminum silicates as major components. The iron-rich vanadium tailings from the Salt Lake City site contain appreciable quantities of α-hematite and chloroapatite. The reduction in radon emanation power and changes in mineralogy as a function of sintering temperature are presented

  8. Polyphosphate Amendments for In-Situ Immobilization of Uranium Plumes

    International Nuclear Information System (INIS)

    Wellman, Dawn M.; Icenhower, Jonathan P.; Pierce, Eric M.; McNamara, Bruce K.; Burton, Sarah D.; Geiszler, Keith N.; Baum, Steven R.; Butler, Bart C.; R.F. Olfenbuttel; P.J. White

    2005-01-01

    A multi-faceted approach has been taken to address basic science questions with regards to the efficacy of utilizing phosphate amendments for subsurface immobilization of uranium plumes. Hydraulically saturated and unsaturated column tests demonstrate the ability of polyphosphate compounds to control the precipitation kinetics of insoluble phosphate minerals and optimize conditions for controlled application of phosphate amendments for subsurface remediation. X-Ray micro-focus tomography results illustrate long-term effects of phosphate mineralization on hydraulic conductivity. 31P NMR has been utilized to quantify the effect of sedimentary and aqueous components on the in-situ hydrolysis kinetics of condensed polyphosphates. Single-pass flow-through (SPFT) tests have been conducted to evaluate the longevity and quantify the effects of aqueous organic material on the dissolution kinetics of autunite minerals, X1-2[(UO2)(PO4)]2nH2O. Preliminary results indicate: (1) autunite minerals will precipitate within 1-2 months given a 0.05 M phosphate concentration and 10-6 M aqueous uranium concentration, under hydraulically saturated conditions; (2) polyphosphate chain lengths can be optimized for specific site conditions, given thorough knowledge of the subsurface environment; (3) the release of uranium from autunite minerals appears to be 6-7 order of magnitude slower than uranium (UO2) minerals formed by iron barrier reduction; and (4) understanding secondary uranyl-phase formation is necessary for predicting the long-term fate of uranium in the environment

  9. Groundwater restoration with in situ uranium leach mining

    International Nuclear Information System (INIS)

    Charbeneau, R.J.

    1984-01-01

    In situ leach mining of uranium has developed into a major mining technology. Since 1975, when the first commercial mine was licensed in the United States, the percentage or uranium produced by in situ mining has steadily grown from 0.6 to 10 percent in 1980. Part of the reason for this growth is that in situ mining offers less initial capital investment, shorter start-up times, greater safety, and less labor than conventional mining methods. There is little disturbance of the surface terrain or surface waters, no mill tailings piles, and no large open pits, but in situ leaching mining does have environmental disadvantages. During the mining, large amounts of ground water are cirulated and there is some withdrawal from an area where aquifers constitute a major portion of the water supply for other purposes. When an ammonia-based leach system is used, the ammonium ion is introduced into an area where cation exchange on clays (and some production of nitrate) may occur. Also, injection of an oxidant with the leach solution causes valence and phase changes of indigenous elements such as As, Cu, Fe, Mo, Se, S, and V as well as U. Furthermore, the surrounding ground water can become contaminated by escape of the leach solution from the mining zone. This chapter presents an overview of the in situ mining technology, including uranium deposition, mining techniques, and ground water restoration alternatives. The latter part of the chapter covers the situation in South Texas. Economics and development of the industry, groundwater resources, regulation, and restoration activities are also reviewed

  10. In-situ leaching opens new uranium reserves in Texas

    International Nuclear Information System (INIS)

    White, L.

    1975-01-01

    A commercial in-situ uranium leaching operation that is quite probably the largest ever built started up in April, 10 mi southwest of George West, Tex. Producing from a pattern of 66 injection wells and 46 extraction wells occupying an area of less than 3 acres, the Clay West mine and plant are expected to reach design capacity of 250,000 lb per year of yellowcake by the end of the summer. By late May, results were sufficiently favorable to make the owners think seriously about an early expansion. Built at a cost of $7 million by joint ventures Atlantic Richfield (50 percent owner and operator), Dalco (25 percent), and US Steel (25 percent), the Clay West mine may be only the first of several mines to extract U 3 O 8 from a uranium province that stretches from north of Houston to Brownsville, at the southernmost tip of the state. Westinghouse subsidiary Wyoming Minerals is building a 250,000-lb-per-year plant near Bruni, with startup planned before the end of 1975, and Mobil Oil is setting up a pilot-scale plant in the same area. A number of other companies are reported to be actively interested in development of in-situ uranium leaching in Texas. (U.S.)

  11. Uranium in situ leach mining in the United States. Information circular

    International Nuclear Information System (INIS)

    Larson, W.C.

    1978-01-01

    This report discusses uranium in situ leach mining in the United States; the purpose of which is to acquaint the reader with an overview of this emerging mining technology. This report is not a technical discussion of the subject matter, but rather should be used as a reference source for information on in situ leaching. An in situ leaching bibliography is included as well as engineering data tables for almost all of the active pilot-scale and commercial uranium in situ leaching operators. These tables represent a first attempt at consolidating operational data in one source, on a regional scale. Additional information is given which discusses the current Bureau of Mines uranium in situ leaching research program. Also included is a listing of various State and Federal permitting agencies, and a summary of the current uranium in situ leaching operators. Finally, a glossary of terms has been added, listing some of the more common terms used in uranium in situ leach mining

  12. Aquifer restoration at uranium in situ leach sites

    International Nuclear Information System (INIS)

    Anastasi, F.S.; Williams, R.E.

    1985-01-01

    In situ mining of uranium involves injection of a leaching solution (lixiviant) into an ore-bearing aquifer. Frequently, the ground water in the mined aquifer is a domestic or livestock water supply. As the lixiviant migrates through the ore body, uranium and various associated elements such as arsenic, selenium, molybdenum, vanadium and radium-226 are mobilized in the ground water. Aquifer restoration after in situ mining is not fully understood. Several methods have been developed to restore mined aquifers to pre-mining (baseline) quality. Commonly used methods include ground water sweeping, clean water injection, and treatment by ion exchange and reverse osmosis technologies. Ammonium carbonate lixiviant was used at one RandD in situ mine. Attempts were made to restore the aquifer using a variety of methods. Efforts were successful in reducing concentrations of the majority of contaminants to baseline levels. Concentrations of certain parameters, however, remained at levels above baseline six months after restoration ceased. Relatively large quantities of ground water were processed in the restoration attempt considering the small size of the project (1.25 acre). More thorough characterization of the hydrogeology of the site may have enhanced the effectiveness of restoration and reduced potential environmental impacts associated with the project. This paper presents some of the findings of a research project conducted by the Mineral Resources Waste Management Team at the University of Idaho in Moscow, Idaho. Views contained herein do not reflect U.S. Nuclear Regulatory Commission policy

  13. In situ leach method for recovering uranium and related values

    International Nuclear Information System (INIS)

    Yan, T.Y.

    1981-01-01

    A process is provided for in-situ leaching of uranium from a calcium-containing clay which does not result in contamination of the clay formation by any cations not already present. A lixiviant is prepared by dissolving carbon dioxide into water having essentially the same cationic composition as that of the formation connate water. The solution is injected along with an oxidant, for example oxygen, into the formation. Calcium that has become dissolved in the lixiviant must be removed to control the pH, preferably by the addition of lime in a calcium precipitator. After calcium removal the lixiviant is filtered to remove suspended solids and is passed through an ion exchange resin or other uranium extraction means. The barren solution goes to a mix tank where carbon dioxide is added, and the fresh lixiviant is injected along with additional oxidant into the formation

  14. Resource impact evaluation of in-situ uranium groundwater restoration

    International Nuclear Information System (INIS)

    Charbeneau, R.J.; Rohlich, G.A.

    1981-11-01

    The purpose of this study was to determine the impact of restoration on the groundwater following in-situ uranium solution mining in South Texas. Restoration is necessary in order to reduce the amounts of undesired chemical constituents left in solution after mining operations have ceased, and thus return the groundwater to a quality consistent with pre-mining use and potential use. Various restoration strategies have been proposed and are discussed. Of interest are the hydrologic, environmental, social, and economic impacts of these restoration alternatives. Much of the discussion concerning groundwater restoration is based on the use of an ammonium carbonate-bicarbonate leach solution in the mining process. This has been the principal leach solution used during the early period of mining in South Texas. Recently, because of apparent difficulties in restoring ammonium to proposed or required levels, many of the companies have changed to the use of other leach solutions. Because little is known about restoration with these other leach solutions they have not been specifically addressed in this report. Likewise, we have not addressed the question of the fate of heavy metals. Following a summary of the development of South Texas in-situ mining in Chapter Two, Chapter Three describes the surface and groundwater resources of the uranium mining district. Chapter Four addresses the economics of water use, and Chapter Five is concerned with regulation of the in-situ uranium industry in Texas. A discussion of groundwater restoration alternatives and impacts is presented in Chapter Six. Chapter Seven contains a summary and a discussion, and conclusions derived from this study. Two case histories are presented in Appendices A and B

  15. Selection of lixiviants for in situ uranium leaching. Information circular

    International Nuclear Information System (INIS)

    Tweeton, D.R.; Peterson, K.A.

    1981-10-01

    This Bureau of Mines publication provides information to assist in selecting a lixiviant (leach solution) for in situ uranium leaching. The cost, advantages, and disadvantages of lixiviants currently used and proposed are presented. Laboratory and field tests are described, and applications of geochemical models are discussed. Environmental, economic, and technical factors should all be considered. Satisfying environmental regulations on restoring groundwater quality is becoming an overriding factor, favoring sodium bicarbonate or dissolved carbon dioxide over ammonium carbonate. The cheapest lixiviant is dissolved carbon dioxide, but it is not effective in all deposits. Technical factors include clay swelling by sodium, acid consumption by calcite, and the low solubility of oxygen in shallow deposits

  16. Groundwater restoration of in-situ uranium mines

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    In-situ leaching is a relatively new uranium production technology that is expected to account for a growing share of future output. Depending upon the leaching solution used, the process may have considerable impact on the ground water. Since restoration of ground water quality is required in most countries and since this restoration is by far the most costly aspect of reclamation of an in-situ mine, it is necessary to utilize a process that lends itself both to the efficiency of the leaching process and the restoration process. This article examines a number of techniques that may be used in the restoration efforts. These include: (1) groundwater sweep, (2) reverse osmosis, (3) chemical restoration, and (4) electrodialysis. The article also discusses disposal of the excess fluids used in the restoration process

  17. The method for the in-situ leaching of a uranium mining

    International Nuclear Information System (INIS)

    Chen Zhen; Xu Xianyi; Wang Xuemin

    2011-01-01

    The paper reviews the main factors of in-situ leaching for uranium mining. A kind of technique called dilution with few reagent is put forward to the in-situ leaching of sandstone-type uranium deposit with high TDS. This technique can not only effectively prevent the pipe plug, but also can improve the economic benefits. (authors)

  18. Introduction to in situ leaching technique and facility at Smith Ranch uranium project in USA

    International Nuclear Information System (INIS)

    Xu Lechang; Wang Delin; Sun Xianrong; Gao Shangxiong

    2005-01-01

    The history of in situ leaching of uranium in USA is reviewed. Some techniques and parameters of alkaline in situ leach at Smith Ranch uranium project are introduced, including well field, sorption, elution, precipitation, filter and drying, automatic control, radiation protection, safety and environmental protection. (authors)

  19. The application of geophysical logging at in-situ leaching uranium mine in China

    International Nuclear Information System (INIS)

    Liu Zeyao; Xu Shusheng; Li Zhongqiu

    1999-01-01

    The status of work, instrument and method employed for geophysical logging in different stages at in-situ leaching uranium mine are discussed and the development of software, electrical current logging and gamma ray logging are presented based on the requirement of in-situ leaching of uranium. In addition, new function and method with regard to home instrument are proposed for future work

  20. Feasibility testing of in situ vitrification of uranium-contaminated soils

    International Nuclear Information System (INIS)

    Ikuse, H.; Tsuchino, S.; Tasaka, H.; Timmerman, C.L.

    1989-01-01

    Process feasibility studies using in situ vitrification (ISV) were successfully performed on two different uranium-contaminated wastes. In situ vitrification is a thermal treatment process that converts contaminated soils into durable glass and crystalline form. Of the two different wastes, one waste was uranium mill tailings, while the other was uranium-contaminated soils which had high water contents. Analyses of the data from the two tests are presented

  1. 76 FR 41308 - Strata Energy, Inc., Ross In Situ Recovery Uranium Project, Crook County, WY; Notice of Materials...

    Science.gov (United States)

    2011-07-13

    ..., Inc., Ross In Situ Recovery Uranium Project, Crook County, WY; Notice of Materials License Application...-4737, or by e-mail to [email protected] . The Ross In Situ Recovery Uranium Project License... source and byproduct materials license at its Ross In Situ Recovery Uranium Project site located in Crook...

  2. Preliminary discussion on uranium metallogenic models of China's in-situ leachable sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    Zhang Jindai; Xu Gaozhong; Chen Anping; Wang Cheng

    2005-01-01

    By comprehensively analyzing metallogenic environments and main ore-controlling factors of important uranium metallogenic regions of in-situ leachable sandstone-type uranium deposits at the southern margin of Yili basin, at the south-western margin of Turpan-Hami basin and in the northeastern Ordos basin, the authors of this paper discuss the metallogenic models of China's in-situ leachable sandstone-type uranium deposits, and suggest that the interlayer oxidation zone type uranium deposits in Yili and Turpan-Hami basins are basically controlled by favourable structures, sedimentary formations and interlayer oxidation zone, and are characterized by multistage uranium concentration, namely the uranium pre-concentration of ore-hosting sedimentary formation, the uranium ore-formation in the stage of supergenic epigenetic reworking, and the further superimposition enrichment of post-ore tectonic activity. However, the interlayer oxidation zone type uranium deposit in the northeastern Ordos was formed after the formation of the secondary reduction. So, paleo-interlayer oxidation zone type uranium mineralization has the mineralization size much greater than the former two. (authors)

  3. Analysis of groundwater criteria and recent restoration attempts after in situ uranium leaching. Open file report

    International Nuclear Information System (INIS)

    Buma, G.; Johnson, P.H.; Bienek, G.K.; Watson, C.G.; Noyes, H.J.

    1981-10-01

    Groundwater restoration is an important aspect of in situ uranium leaching. Information on the effectiveness of the current technology, costs, and the current State and Federal Government permitting regulations is of vital importance to in situ leach operators and firms considering in situ leaching. This study describes (1) all recent restoration attempts at commercial in situ leaching operations, (2) restoration costs reported by the industry, (3) empirical equations that predict the amount of groundwater flushing required to meet the current restoration criteria, and (4) in situ uranium permit requirements for the States of Texas, Wyoming, New Mexico, Utah, Montana, Colorado, and South Dakota, and Federal requirements

  4. An evaluation of health risk to the public as a consequence of in situ uranium mining in Wyoming, USA.

    Science.gov (United States)

    Ruedig, Elizabeth; Johnson, Thomas E

    2015-12-01

    In the United States there is considerable public concern regarding the health effects of in situ recovery uranium mining. These concerns focus principally on exposure to contaminants mobilized in groundwater by the mining process. However, the risk arising as a result of mining must be viewed in light of the presence of naturally occurring uranium ore and other constituents which comprise a latent hazard. The United States Environmental Protection Agency recently proposed new guidelines for successful restoration of an in situ uranium mine by limiting concentrations of thirteen groundwater constituents: arsenic, barium, cadmium, chromium, lead, mercury, selenium, silver, nitrate (as nitrogen), molybdenum, radium, total uranium, and gross α activity. We investigated the changes occurring to these constituents at an ISR uranium mine in Wyoming, USA by comparing groundwater quality at baseline measurement to that at stability (post-restoration) testing. Of the groundwater constituents considered, only uranium and radium-226 showed significant (p < 0.05) deviation from site-wide baseline conditions in matched-wells. Uranium concentrations increased by a factor of 5.6 (95% CI 3.6-8.9 times greater) while radium-226 decreased by a factor of about one half (95% CI 0.42-0.75 times less). Change in risk was calculated using the RESRAD (onsite) code for an individual exposed as a resident-farmer; total radiation dose to a resident farmer decreased from pre-to post-mining by about 5.2 mSv y(-1). Higher concentrations of uranium correspond to increased biomarkers of nephrotoxicity, however the clinical significance of this increase is unclear. Published by Elsevier Ltd.

  5. Field Testing of Downgradient Uranium Mobility at an In-Situ Recovery Uranium Mine

    Science.gov (United States)

    Reimus, P. W.; Clay, J. T.; Rearick, M.; Perkins, G.; Brown, S. T.; Basu, A.; Chamberlain, K.

    2015-12-01

    In-situ recovery (ISR) mining of uranium involves the injection of O2 and CO2 (or NaHCO3) into saturated roll-front deposits to oxidize and solubilize the uranium, which is then removed by ion exchange at the surface and processed into U3O8. While ISR is economical and environmentally-friendly relative to conventional mining, one of the challenges of extracting uranium by this process is that it leaves behind a geochemically-altered aquifer that is exceedingly difficult to restore to pre-mining geochemical conditions, a regulatory objective. In this research, we evaluated the ability of the aquifer downgradient of an ISR mining area to attenuate the transport of uranium and other problem constituents that are mobilized by the mining process. Such an evaluation can help inform both regulators and the mining industry as to how much restoration of the mined ore zone is necessary to achieve regulatory compliance at various distances downgradient of the mining zone even if complete restoration of the ore zone proves to be difficult or impossible. Three single-well push-pull tests and one cross-well test were conducted in which water from an unrestored, previously-mined ore zone was injected into an unmined ore zone that served as a geochemical proxy for the downgradient aquifer. In all tests, non-reactive tracers were injected with the previously-mined ore zone water to allow the transport of uranium and other constituents to be compared to that of the nonreactive species. In the single-well tests, it was shown that the recovery of uranium relative to the nonreactive tracers ranged from 12-25%, suggesting significant attenuation capacity of the aquifer. In the cross-well test, selenate, molybdate and metavanadate were injected with the unrestored water to provide information on the transport of these potentially-problematic anionic constituents. In addition to the species-specific transport information, this test provided valuable constraints on redox conditions within

  6. In situ spectroscopy and spectroelectrochemistry of uranium in high-temperature alkali chloride molten salts.

    Science.gov (United States)

    Polovov, Ilya B; Volkovich, Vladimir A; Charnock, John M; Kralj, Brett; Lewin, Robert G; Kinoshita, Hajime; May, Iain; Sharrad, Clint A

    2008-09-01

    Soluble uranium chloride species, in the oxidation states of III+, IV+, V+, and VI+, have been chemically generated in high-temperature alkali chloride melts. These reactions were monitored by in situ electronic absorption spectroscopy. In situ X-ray absorption spectroscopy of uranium(VI) in a molten LiCl-KCl eutectic was used to determine the immediate coordination environment about the uranium. The dominant species in the melt was [UO 2Cl 4] (2-). Further analysis of the extended X-ray absorption fine structure data and Raman spectroscopy of the melts quenched back to room temperature indicated the possibility of ordering beyond the first coordination sphere of [UO 2Cl 4] (2-). The electrolytic generation of uranium(III) in a molten LiCl-KCl eutectic was also investigated. Anodic dissolution of uranium metal was found to be more efficient at producing uranium(III) in high-temperature melts than the cathodic reduction of uranium(IV). These high-temperature electrolytic processes were studied by in situ electronic absorption spectroelectrochemistry, and we have also developed in situ X-ray absorption spectroelectrochemistry techniques to probe both the uranium oxidation state and the uranium coordination environment in these melts.

  7. In-situ grouting of uranium-mill-tailings piles: an assessment

    International Nuclear Information System (INIS)

    Tamura, T.; Boegly, W.J. Jr.

    1983-05-01

    Passage in 1978 of the Uranium Mill Tailings Radiation Control Act (UMTRCA) initiated a program of remedial action for 22 existing mill tailings piles generated in the period 1940 to 1970 as part of the nation's defense and nuclear power programs. The presence of these piles poses potential health and environmental contamination concerns. Possible remedial actions proposed include multilayer covers over the piles to reduce water infiltration, reduce radon gas releases, and reduce airborne transport of tailings fines. In addition, suggested remedial actions include (1) the use of liners to prevent groundwater contamination by leachates from the piles and (2) chemical stabilization of the tailings to retain the radioactive and nonradioactive sources of contamination. Lining of the piles would normally be applicable only to piles that are to be moved from their present location such that the liner could be placed between the tailings and the groundwater. However, by using civil engineering techniques developed for grouting rocks and soils for strength and water control, it may be possible to produce an in situ liner for piles that are not to be relocated. The Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project Office requested that ORNL assess the potential application of grouting as a remedial action. This report examines the types of grouts, the equipment available, and the costs, and assesses the possibility of applying grouting technology as a remedial action alternative for uranium mill tailings piles

  8. In-situ grouting of uranium-mill-tailings piles: an assessment

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, T.; Boegly, W.J. Jr.

    1983-05-01

    Passage in 1978 of the Uranium Mill Tailings Radiation Control Act (UMTRCA) initiated a program of remedial action for 22 existing mill tailings piles generated in the period 1940 to 1970 as part of the nation's defense and nuclear power programs. The presence of these piles poses potential health and environmental contamination concerns. Possible remedial actions proposed include multilayer covers over the piles to reduce water infiltration, reduce radon gas releases, and reduce airborne transport of tailings fines. In addition, suggested remedial actions include (1) the use of liners to prevent groundwater contamination by leachates from the piles and (2) chemical stabilization of the tailings to retain the radioactive and nonradioactive sources of contamination. Lining of the piles would normally be applicable only to piles that are to be moved from their present location such that the liner could be placed between the tailings and the groundwater. However, by using civil engineering techniques developed for grouting rocks and soils for strength and water control, it may be possible to produce an in situ liner for piles that are not to be relocated. The Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project Office requested that ORNL assess the potential application of grouting as a remedial action. This report examines the types of grouts, the equipment available, and the costs, and assesses the possibility of applying grouting technology as a remedial action alternative for uranium mill tailings piles.

  9. Situ leaching uranium mining conditions of the pilot phase of the safety management

    International Nuclear Information System (INIS)

    Liu Wenyuan

    2014-01-01

    With China's large, very large sandstone type uranium deposits have been discovered in the Ordos Basin, Inner Mongolia and its surrounding for uranium mining in the region has been carried out. Sandstone-type uranium mining, mainly used in China is 'to dip' and the technology is relatively mature. Situ leaching mining process, the deposit conditions Test conditions pilot phase, however, limited by cost control and field conditions, equipment shabby, out in the conditions of the pilot phase of security issues in the larger securityrisks. This will be Ordos ongoing test conditions situ leaching uranium mines, for example, raised situ leaching uranium mining conditions of the pilot phase a few safety measures recommended. (author)

  10. In situ leaching process for recording uranium values

    International Nuclear Information System (INIS)

    McKnight, W.M.; Timmins, T.H.; Sherry, H.S.

    1977-01-01

    A method of recovering uranium values from a subterranean deposit comprising: injecting an alkaline carbonate lixiviant into said deposit; flowing said alkaline carbonate lixiviant through said deposit to dissolve said uranium values into said lixiviant; producing said lixiviant and said dissolved uranium values from said deposit; flowing said lixiviant and said dissolved uranium values through an adsorption material to adsorp said uranium values from said lixiviant; eluting said adsorption material with an eluant of ammonium carbonate to desorb said uranium values from said adsorption material into said eluate in a concentration greater than in said lixiviant; heating said eluate and said desorbed uranium values to vaporize off ammonia and carbon dioxide therefrom, thereby causing uranium values to crystallize from the eluate; and recovering said solid uranium values

  11. Problem-oriented software for the managing of uranium mining by in-situ leaching

    International Nuclear Information System (INIS)

    Noskov, M.D.; Gutsul, M.V.; Istomin, A.D.; Kesler, A.G.; Noskova, S.N.; Cheglokov, A.A.

    2013-01-01

    The problem-oriented software consisting of interconnected geological geoinformation, technological information, geotechnological modeling and expert-analytical systems is presented. The software application procedure for the managing of uranium field development by in-situ leaching is considered [ru

  12. A study on prediction of uranium concentration in pregnant solution from in-situ leaching

    International Nuclear Information System (INIS)

    Yi Weiping; Zhou Quan; Yu Yunzhen; Wang Shude; Yang Yihan; Lei Qifeng

    2005-01-01

    The modeling course on prediction of uranium concentration in pregnant solution from in-situ leaching of uranium is described, a mathematical model based on grey system theory is put forward, and a set of computer application software is correspondingly developed. (authors)

  13. Environmental restoration. Stabilization of mining tailing and uranium mineral

    International Nuclear Information System (INIS)

    Perez, C.; Carboneras, P.

    1998-01-01

    ENRESA has dismantling a uranium mill facility and restored the site since 1991 to 1994. Since 1997, 19 uranium mines are being re mediated. The Andujar uranium mill was operational since 1959 to 1981. The remedial action plan performed in the Andujar mill site involved stabilizing and consolidating the uranium mill tailings and contaminated materials in place. Mill equipment, building and process facilities have been dismantled and demolished and the resulting metal wastes and debris have been placed in the pile. The tailings mass has been reshape by flattening the side slopes and cover system was placed over the pile. The uranium mines are located in Extremadura and Andalucia. There is a great diversity among the mines in terms of the magnitude of the disturbed areas by mining work and the effects on the environment, including excavations, waste rock piles, abandoned shafts and galleries, and remaining of surface structures and facilities. Remedial measures include the sealing for shafts and openings to prevent collapse of mine workings and subsidence, the dewatering and the open-pit excavation and the treatment of the contaminated waters, the disposal and the stabilization of mining debris piles to prevent dispersion, the placement of a re vegetated cover over the piles to control dust and erosion, and the restoration of the site. (Author)

  14. In-Well Sediment Incubators to Evaluate Microbial Community Stability and Dynamics following Bioimmobilization of Uranium

    International Nuclear Information System (INIS)

    Baldwin, Brett R.; Peacock, Aaron D.; Gan, M.; Resch, Charles T.; Arntzen, Evan V.; Smithgall, A.N.; Pfiffner, S.; Freifeld, Barry M.; White, D.C.; Long, Philip E.

    2009-01-01

    An in-situ incubation device (ISI) was developed in order to investigate the stability and dynamics of sediment associated microbial communities to prevailing subsurface oxidizing or reducing conditions. Here we describe the use of these devices at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site. During the 7 month deployment oxidized Rifle aquifer background sediments (RABS) were deployed in previously biostimulated wells under iron reducing conditions, cell densities of known iron reducing bacteria including Geobacteraceae increased significantly showing the microbial community response to local subsurface conditions. PLFA profiles of RABS following in situ deployment were strikingly similar to those of adjacent sediment cores suggesting ISI results could be extrapolated to the native material of the test plots. Results for ISI deployed reduced sediments showed only slight changes in community composition and pointed toward the ability of the ISIs to monitor microbial community stability and response to subsurface conditions.

  15. Supplementary recovery of uranium by in-situ leaching at the Brugeaud deposit (Limousin, France)

    International Nuclear Information System (INIS)

    Lyaudet, G.

    1980-01-01

    The actual mining operations at the Brugeaud Deposit (West Brugeaud and East Brugeaud) were followed by supplementary recoveries of uranium by means of in-situ leaching. There were a number of factors which favoured consideration of these operations: the amounts of uranium present at the edge of the stoped areas; the underground mining infrastructure, which did not require supplementary operations for the recovery of solutions; the nature of the rock, which presented a dense network of fractures and micro-fractures conducive to impregnation by the acid solutions; and the immediate proximity of a concentration plant. The amount of uranium recovered by in-situ leaching is close to 200 t. This production is approximately nine per cent of all the uranium extracted from the deposit. The cost of the metal obtained in this way was always less than FF 100 (FF of 1978) per kilogram of uranium. (author)

  16. Uranium in situ leaching: its advantages, practice, problems and computer simulation

    International Nuclear Information System (INIS)

    Hancock, B.A.

    1977-01-01

    In situ leaching for the recovery of uranium from low grade sandstone deposits is one of the newest technological advances in the mineral industry. It is rapidly developing into a commercially feasible mining system which has economic, environmental, and social advantages over conventional mining systems. Because of the current uranium shortage, development of in situ leaching into a sophisticated system has gained new impetus. In situ leaching will become an important mining technique in the future, which will greatly help to supply uranium for the United States' energy needs. In this paper, the author gives an overview of the merits of the system, as well as the technology problems, and research in solution mining of uranium. 17 references

  17. In situ gamma-ray spectrometric measurements of uranium in phosphates soil

    International Nuclear Information System (INIS)

    Lavi, N.; Ne'eman, E.; Brenner, S.; Haquin, G.; Nir-El, Y.

    1997-01-01

    Abstract Radioactivity concentration of 238 U in a phosphate ores quarry was measured in situ. Independently, soil samples collected in the site were measured in the laboratory. It was disclosed that radon emanation from the soil lowers in situ results that are derived from radon daughters. Uranium concentration was found to be 121.6±1.9 mg kg -1 (authors)

  18. Internal hydrogen embrittlement of gamma-stabilized uranium alloys

    International Nuclear Information System (INIS)

    Powell, G.L.; Koger, J.W.; Bennett, R.K.; Williamson, A.L.; Hemperly, V.C.

    1976-01-01

    Relationships between the tensile ductility and fracture characteristics of as-quenched, gamma-stabilized uranium alloys (uranium--10 wt percent molybdenum, uranium--8.5 wt percent niobium, uranium--10 wt percent niobium, and uranium--7.5 wt percent niobium--2.5 wt percent zirconium), the hydrogen content of the tensile specimens, and the hydrogen gas pressure during the annealing at 850 0 C of the tensile test blanks prior to quenching were established. For these alloys, the tensile ductility decreases only slightly with increasing hydrogen content up to a critical hydrogen concentration above which the tensile ductility drops to nearly zero. The only alloy not displaying this sharp drop in tensile ductility was U--7.5 Nb--2.5 Zr, probably because sufficiently high hydrogen contents could not be achieved under our experimental arrangements. The critical hydrogen content for ductility loss increased with increasing hydrogen solubility in the alloy. Fracture surfaces produced by internal hydrogen embrittlement do not resemble those produced by stress corrosion cracking (SCC) in aqueous environments containing chloride ions. 8 figs

  19. Study on tertiary in-situ leachable uranium mineralization conditions in South Songliao basin

    International Nuclear Information System (INIS)

    Zhang Zhenqiang; Li Guokuan; Zhao Zonghua; Zhang Jingxun

    2001-01-01

    Tertiary in-situ leachable mineralization in Songliao Basin was analyzed in theory in the past. Since 1998, regional investigation at 1:200000 scale has been done with about 120 holes drilled. Based on drill holes recording, section compiling and sample analysis, the authors investigate into the Tertiary in-situ leachable conditions including rock character, sedimentary facies, rock chemistry, organic substances, uranium content, sandstone porosity, sandstone bodies, interlayer oxidation, and hydro-dynamic value. The study would play important role in prospecting for in-situ leachable uranium in South Songliao basin

  20. Remediation of SRS Basins by In Situ Stabilization/Solidification

    International Nuclear Information System (INIS)

    Ganguly, A.

    1999-01-01

    In the late summer of 1998, the Savannah River Site began remediation of two radiologically contaminated basins using in situ stabilization. These two high-risk, unlined basins contain radiological contaminants, which potentially pose significant risks to human health and the environment. The selected remedy involves in situ stabilization/solidification of the contaminated wastes (basin and pipeline soils, pipelines, vegetation, and other debris) followed by installation of a low permeability soil cover

  1. Fission products stability in uranium dioxide

    International Nuclear Information System (INIS)

    Brillant, G.; Gupta, F.; Pasturel, A.

    2011-01-01

    Fission product stability in nuclear fuels is investigated using density functional theory (DFT). In particular, incorporation and solution energies of He, Kr, Xe, I, Te, Ru, Sr and Ce in pre-existing trap sites of UO 2 (vacancies, interstitials, U-O divacancy, and Schottky trio defects) are calculated using the projector-augmented-wave method as implemented in the Vienna ab initio simulation package. Correlation effects are taken into account within the DFT+U approach. The stability of many binary and ternary compounds in comparison to soluted atoms is also explored. Finally the involvement of FP in the formation of metallic and oxide precipitates in oxide fuels is discussed in the light of experimental results.

  2. Preparation and thermochemical stability of uranium-zirconium-carbonitrides

    International Nuclear Information System (INIS)

    Kouhsen, C.

    1975-08-01

    This investigation deals with the preparation and the thermochemical stability of uranium-zirconium-carbonitrides as well as with the mechanism of (U,Zr) (C,N)-preparation by carbothermic reduction of uranium-zirconium-oxide. Single-phase (U,Zr) (C,N)-solid solutions with U:Zr-propertions of 3:1, 1:1, and 1:3 were prepared from oxide powder. The thermochemical stability of the (U,Zr) (C,N)-solid solutions against carbon was measured for varying Zr- and N-contents and for several temperatures; the results indicate an increase of the uranium carbide stability potential by the formation of (U,Zr) (C,N)-solid solutions. The thermodynamic properties ΔG 0 , ΔH 0 , and ΔS 0 were calculated and the correlation between the M(C,N)-lattice constant and the N-content was evaluated. Through an intensive investigation of the reaction mechanism, several different reaction paths were found; for each of them the characteristical diffusion of matter was explained by means of the microsections. It was shown that the Zr-concentration of the oxide reactant and the heating rate during the carbothermic reduction influence the species of the reaction product, especially the homogeneity of the (U,Zr) (C,N)-solid solution. (orig.) [de

  3. Radiometric determination in situ of the face grades in Witwatersrand gold and uranium mines

    International Nuclear Information System (INIS)

    Smit, C.J.B.

    1985-01-01

    A prototype collimated radiometric face scanner was tested in the Harmony Gold Mine. The results obtained during the pilot study indicate that in situ radiometric uranium assays are statistically indistinguishable from those obtained conventionally from channel chip samples. In addition, the study demonstrated that reasonably reliable gold estimates can be deduced from the radiometric measurements, by use of the ratio of gold to uranium within a mine. The instrumentation, calibration procedures, and background determination are described briefly

  4. Remotely operated facility for in situ solidification of fissile uranium

    International Nuclear Information System (INIS)

    McGinnis, C.P.; Collins, E.D.; Patton, B.D.

    1986-01-01

    A heavily shielded, remotely operated facility, located within the Radiochemical processing Plant at Oak Ridge National Laboratory (ORNL), has been designed and is being operated to convert approx.1000 kg of fissile uranium (containing approx.75% 235 U, approx.10% 233 U, and approx.140 ppM 232 U) from a nitrate solution (130 g of uranium per L) to a solid oxide form. This project, the Consolidated Edison Uranium Solidification Program (CEUSP), is being carried out in order to prepare a stable uranium form for longterm storage. This paper describes the solidification process selected, the equipment and facilities required, the experimental work performed to ensure successful operation, some problems that were solved, and the initial operations

  5. Bioreduction and immobilization of uranium in situ: a case study at a USA Department of Energy radioactive waste site, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Wu, Weimin; Carley, Jack M.; Watson, David B.; Gu, Baohua; Brooks, Scott C.; Kelly, Shelly D.; Kemner, Kenneth M.; Van Nostrand, Joy; Wu, Liyou; Zhou, Jizhong; Luo, Jian; Cardenas, Erick; Fields, Matthew Wayne; Marsh, Terence; Tiedje, James; Green, Stefan; Kostka, Joel; Kitanidis, Peter K.; Jardine, Philip; Criddle, Craig

    2011-01-01

    Bioremediation of uranium contaminated groundwater was tested by delivery of ethanol as an electron donor source to stimulate indigenous microbial bioactivity for reduction and immobilization of uranium in situ, followed by tests of stability of uranium sequestration in the bioreduced area via delivery of dissolved oxygen or nitrate at the US Department of energy's Integrated Field Research Challenge site located at Oak Ridge, Tennessee, USA. After long term treatment that spanned years, uranium in groundwater was reduced from 40-60 mg · L -1 to -1 , below the USA EPA standard for drinking water. The bioreduced uranium was stable under anaerobic or anoxic conditions, but addition of DO and nitrate to the bioreduced zone caused U remobilization. The change in the microbial community and functional microorganisms related to uranium reduction and oxidation were characterized. The delivery of ethanol as electron donor stimulated the activities of indigenous microorganisms for reduction of U(VI) to U(IV). Results indicated that the immobilized U could be partially remobilized by D0 and nitrate via microbial activity. An anoxic environmental condition without nitrate is essential to maintain the stability of bioreduced uranium.

  6. 77 FR 70486 - Supplemental Environmental Impact Statement for Proposed Dewey-Burdock In-Situ Uranium Recovery...

    Science.gov (United States)

    2012-11-26

    ... Proposed Dewey- Burdock In-Situ Uranium Recovery Project in Custer and Fall River Counties, SD AGENCY... draft Supplemental Environmental Impact Statement (Draft SEIS) for the Dewey-Burdock In-Situ Uranium... NRC for a new source materials license for the Dewey-Burdock ISR Project. Powertech is proposing to...

  7. 78 FR 19330 - Supplemental Environmental Impact Statement for the Ross In-Situ Uranium Recovery Project in...

    Science.gov (United States)

    2013-03-29

    ... Ross In-Situ Uranium Recovery Project in Crook County, Wyoming AGENCY: Nuclear Regulatory Commission... Commission (NRC) for a new source materials license for the proposed Ross In-Situ Uranium Recovery (ISR) Project (Ross Project) proposed to be located in Crook County, Wyoming. The NRC is issuing for public...

  8. Report on the feasibility of the in situ radiometric determination of uranium grade in Witwatersrand gold and uranium mines

    International Nuclear Information System (INIS)

    Smit, C.J.B.; Wesolinski, E.S.; Corner, B.

    1982-08-01

    The chip-sampling technique currently employed by the South African gold and uranium-mining industry, for the prediction of face grade, has several drawbacks, namely: 1) it is labour-intensive; 2) sample volumes are often unrepresentative and prone to human error; and 3) the uranium mineralisation may be very erratic along the reef. In situ radiometric assaying for uranium along the reef, on the other hand, is a rapid, essentially one-man operation, enabling a much larger and hence a more representative sample volume to be measured. The high radiometric background inherent in any uranium mine necessitates some form of high-density shielding in order to facilitate quantitative in situ assaying. This report, therefore, briefly outlines the origin, nature, detection and shielding of gamma rays. Results obtained with a frontally shielded total-count instrument showed that radiometric estimates of uranium grade are comparable to those obtained by batch mining and can be used for the prediction of face grades, provided that the ore is in radiometric equilibrium and that thorium and potassium are either not present, or vary sympathetically with the uranium grade. Spectral analysis showed, however, that these circumstances will also permit the use of a collimated (side-shielded) detector of acceptable weight, provided that only the low-energy portion of the spectrum is measured. The advantages of a collimated detector over a frontally shielded detector are also noteworthy, viz.: 1) only one reading is taken per sample point rather than two, as is the case with the frontally shielded system, thus improving counting statistics; and 2) the shielding is permanently fixed to the detector. Comprehensive design considerations for a compact, portable instrument are suggested and methods for determining background radiation as applicable to a collimated detector are described

  9. Following the electroreduction of uranium dioxide to uranium in LiCl–KCl eutectic in situ using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L.D.; Abdulaziz, R.; Jervis, R.; Bharath, V.J. [Electrochemical Innovation Lab, Dept. Chemical Engineering, UCL, London WC1E 7JE (United Kingdom); Atwood, R.C.; Reinhard, C.; Connor, L.D. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Simons, S.J.R.; Inman, D.; Brett, D.J.L. [Electrochemical Innovation Lab, Dept. Chemical Engineering, UCL, London WC1E 7JE (United Kingdom); Shearing, P.R., E-mail: p.shearing@ucl.ac.uk [Electrochemical Innovation Lab, Dept. Chemical Engineering, UCL, London WC1E 7JE (United Kingdom)

    2015-09-15

    Highlights: • We investigated the electroreduction of UO{sub 2} to U in LiCl/KCL eutectic molten salt. • Combined electrochemical measurement and in situ XRD is utilised. • The electroreduction appears to occur in a single, 4-electron-step, process. • No intermediate compounds were observed. - Abstract: The electrochemical reduction of uranium dioxide to metallic uranium has been investigated in lithium chloride–potassium chloride eutectic molten salt. Laboratory based electrochemical studies have been coupled with in situ energy dispersive X-ray diffraction, for the first time, to deduce the reduction pathway. No intermediate phases were identified using the X-ray diffraction before, during or after electroreduction to form α-uranium. This suggests that the electrochemical reduction occurs via a single, 4-electron-step, process. The rate of formation of α-uranium is seen to decrease during electrolysis and could be a result of a build-up of oxygen anions in the molten salt. Slow transport of O{sup 2−} ions away from the UO{sub 2} working electrode could impede the electrochemical reduction.

  10. Experimental Plan: Uranium Stabilization Through Polyphosphate Injection 300 Area Uranium Plume Treatability Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Wellman, Dawn M.; Fruchter, Jonathan S.; Vermeul, Vince R.

    2006-09-20

    This Test Plan describes a laboratory-testing program to be performed at Pacific Northwest National Laboratory (PNNL) in support of the 300-FF-5 Feasibility Study (FS). The objective of the proposed treatability test is to evaluate the efficacy of using polyphosphate injections to treat uranium contaminated groundwater in situ. This study will be used to: (1) Develop implementation cost estimates; (2) Identify implementation challenges; and (3) Investigate the technology's ability to meet remedial objectives These activities will be conducted in parallel with a limited field investigation, which is currently underway to more accurately define the vertical extent of uranium in the vadose zone, and in the capillary fringe zone laterally throughout the plume. The treatability test will establish the viability of the method and, along with characterization data from the limited field investigation, will provide the means for determining how best to implement the technology in the field. By conducting the treatability work in parallel with the ongoing Limited Field Investigation, the resulting Feasibility Study (FS) will provide proven, site-specific information for evaluating polyphosphate addition and selecting a suitable remediation strategy for the uranium plume within the FS time frame at an overall cost savings.

  11. Application of anatectic mineralization to prospecting in-situ leachable sandstone type uranium ore in South Songliao Basin

    International Nuclear Information System (INIS)

    Zhao Zhonghua

    2001-01-01

    The deep ore-forming origin is a new theory for prospecting in-situ leachable sandstone type uranium. Tectonics, lithologic and geochemistry are basic forecasting criteria. Previous unconsolidated sand, source area and geochemical barrier are three essential conditions for forming uranium deposit. Metallogenic environment and prospective region are found. Tertiary system is prospective layer for prospecting in-situ leachable sandstone type uranium ore in south Songliao Basin

  12. Diagnosis of In Situ Metabolic State and Rates of Microbial Metabolism During In Situ Uranium Bioremediation with Molecular Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Lovley, Derek R. [University of Massachusetts, Amherst

    2012-11-28

    The goal of these projects was to develop molecule tools to tract the metabolic activity and physiological status of microorganisms during in situ uranium bioremediation. Such information is important in able to design improved bioremediation strategies. As summarized below, the research was highly successful with new strategies developed for estimating in situ rates of metabolism and diagnosing the physiological status of the predominant subsurface microorganisms. This is a first not only for groundwater bioremediation studies, but also for subsurface microbiology in general. The tools and approaches developed in these studies should be applicable to the study of microbial communities in a diversity of soils and sediments.

  13. Long-term stabilization of uranium mill tailings

    International Nuclear Information System (INIS)

    Voorhees, L.D.; Sale, M.J.; Webb, J.W.; Mulholland, P.J.

    1983-01-01

    The primary hazard associated with uranium mill tailings is exposure to a radioactive gas, radon-222, the concentration of which has been correlated with the occurrence of lung cancer. Previous studies on radon attenuation conclude that the placement of earthen cover materials over the tailings is the most effective technique for reducing radioactive emissions and dispersal of tailings. The success of such a plan, however, is dependent on ensuring the long-term integrity of these cover materials. Soil erosion from water and wind is the major natural cause of destabilizing earthen cover materials. Field data related to the control of soil loss are limited and only indirectly apply to the problem of isolation of uranium mill tailings over very long time periods (up to 80,000 a). However, sufficient information is available to determine benefits that will result from the changes in specific design variables and to evaluate the need for different design strategies among potential disposal sites. The three major options available for stabilization of uranium mill tailings are: rock cover, soil and revegetation, or a combination of both on different portions of the tailings cover. The optimal choice among these alternatives depends on site-specific characteristics such as climate and local geomorphology and soils, and on design variables such as embankment, heights and slopes, modification of upstream drainage, and revegetation practices. Generally, geomorphic evidence suggests that use of soil and vegetation alone will not be adequate to reduce erosion on slopes greater than about 5 to 9%

  14. TREATMENT TESTS FOR EX SITU REMOVAL OF CHROMATE & NITRATE & URANIUM (VI) FROM HANFORD (100-HR-3) GROUNDWATER FINAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    BECK MA; DUNCAN JB

    1994-01-03

    This report describes batch and ion exchange column laboratory scale studies investigating ex situ methods to remove chromate (chromium [VI]), nitrate (NO{sub 3}{sup -}) and uranium (present as uranium [VI]) from contaminated Hanford site groundwaters. The technologies investigated include: chemical precipitation or coprecipitation to remove chromate and uranium; and anion exchange to remove chromate, uranium and nitrate. The technologies investigated were specified in the 100-HR-3 Groundwater Treatability Test Plan. The method suggested for future study is anion exchange.

  15. In-situ uranium mining: reservoir engineering aspects of leaching and restoration

    International Nuclear Information System (INIS)

    Kabir, M.I.

    1982-01-01

    To establish the feasibility of in-situ mining of uranium, a push-pull test of an in-situ uranium leaching process, which consists of a single injection/production test well and two observation wells, was designed to evaluate the parameters which govern the uranium production and restorability of a solution mined zone. The test procedure itself consists of injection (push cycle) of a preflush followed by lixiviant, a brief soak period (soak cycle), and subsequent production (pull cycle) into the same well. Based on computer modeling, procedures are defined which permit, for a properly designed test, the determination of both restoration and leaching parameters. The test procedure and design recommendations are also outlined. Two numerical simulators which model field scale uranium production and restoration operations are presented. These simulators are able to accommodate various well patterns and irregular reservoir boundaries, physical dispersion, directional permeability variations (if present), and a variety of injection/production strategies. A streamline-concentration balance technique has been used to develop the models. The assumption of time invariant boundary conditions and no transverse dispersion between the streamlines reduces the two dimensional problem to a bundle of one dimensional ones. It has been further shown that the production well effluent histories can easily be obtained by superposing the solution of the concentration balance equations for a single streamline, and thus reducing computation time significantly. Finally, the simulators have been used to study various reservoir engineering aspects to optimize in-situ uranium production from field scale operations

  16. In-situ uranium mining: reservoir engineering aspects of leaching and restoration

    Energy Technology Data Exchange (ETDEWEB)

    Kabir, M.I.

    1982-01-01

    To establish the feasibility of in-situ mining of uranium, a push-pull test of an in-situ uranium leaching process, which consists of a single injection/production test well and two observation wells, was designed to evaluate the parameters which govern the uranium production and restorability of a solution mined zone. The test procedure itself consists of injection (push cycle) of a preflush followed by lixiviant, a brief soak period (soak cycle), and subsequent production (pull cycle) into the same well. Based on computer modeling, procedures are defined which permit, for a properly designed test, the determination of both restoration and leaching parameters. The test procedure and design recommendations are also outlined. Two numerical simulators which model field scale uranium production and restoration operations are presented. These simulators are able to accommodate various well patterns and irregular reservoir boundaries, physical dispersion, directional permeability variations (if present), and a variety of injection/production strategies. A streamline-concentration balance technique has been used to develop the models. The assumption of time invariant boundary conditions and no transverse dispersion between the streamlines reduces the two dimensional problem to a bundle of one dimensional ones. It has been further shown that the production well effluent histories can easily be obtained by superposing the solution of the concentration balance equations for a single streamline, and thus reducing computation time significantly. Finally, the simulators have been used to study various reservoir engineering aspects to optimize in-situ uranium production from field scale operations.

  17. On bacteria oxidizing enlargement scale test for uranium in-situ leaching at. 381 mine

    International Nuclear Information System (INIS)

    Hu Kaiguang; Wang Qingliang; Liu Yingjiu; Shi Wenge; Hu Shihe; Hu Yincai; Fang Qiu

    1999-01-01

    The results of enlarged scale test of bacteria as oxidizer for uranium in-situ leaching at No 381 mine showed that redox potential of the oxidized absorbed tailing water by bacteria is more than 510 mV, without any effects on after treatments by using bacteria as oxidizer and reduce oxidizer costs 70% compared with H 2 O 2 as oxidizer

  18. Ross In Situ Uranium Recovery Project NESHAP Subpart W Construction Approval

    Science.gov (United States)

    On May 5, 2015, EPA issued a Construction Approval under the National Emission Standards for Hazardous Air Pollutants (NESHAPs) at 40 CFR Part 61, subpart W, to Strata Energy, Inc., for their Ross In Situ Recovery (ISR) Uranium Project in Crook County, WY.

  19. Determination of the stability constants of uranium-tetracycline complexes

    International Nuclear Information System (INIS)

    Tarenzi, L.R.; Saiki, M.

    1983-01-01

    Stability constants of complexes formed with tetracycline (TC) and uranium have been determined by solvent extraction technique. The site on the tetracycline molecule at which uranyl ion may be bound has been studied by means of potentiometric titration and spectrophotometric techniques. The complex species with 1:1 and 1:2 for UO 2 : TC ratio have been identified by conductometric titration. Solvent extraction studies have also shown that the complexes are mononuclear of the type UO 2 (TC) sub (n) (n=1,2) and that no hidroxocomplexes or negatively charged complexes have been formed. Stability constant values have been calculated by numerical weighted least square method and by graphical methods of two parameters, of the average number of ligands and of the limiting value. (Author) [pt

  20. Long-term stabilization of uranium mill tailings

    International Nuclear Information System (INIS)

    Voorhees, L.D.; Sale, M.J.; Webb, J.W.; Mulholland, P.J.

    1984-01-01

    The primary hazard associated with uranium mill tailings is exposure to a radioactive gas, radon-222, the concentration of which has been correlated with the occurrence of lung cancer. Previous studies on radon attenuation conclude that the placement of earthen cover materials over the tailings is the most effective technique for reducing radioactive emissions and dispersal of tailings. The success of such a plan, however, is dependent on ensuring the long-term integrity of these cover materials. Soil erosion from water and wind is the major natural cause of destabilizing earthen cover materials. Field data related to the control of soil loss are limited and only indirectly apply to the problem of isolation of uranium mill tailings over very long time periods (up to 80,000 a). However, sufficient information is available to determine benefits that will result from changes in specific design variables and to evaluate the need for different design strategies among potential disposal sites. The three major options available for stabilization of uranium mill tailings are (1) rock cover, (2) soil and revegetation, or (3) a combination of both on different portions of the tailings cover. The optimal choice among these alternatives depends on site-specific characteristics such as climate and local geomorphology and soils, and on design variables such as embankment heights and slopes, modification of upstream drainage, and revegetation practices. Generally, geomorphic evidence suggests that use of soil and vegetation alone will not be adequate to reduce erosion on slopes greater than about 5 to 9%. For these steeper slopes, the use of rock talus or riprap will be necessary to maximize the probability of long-term stability. The use of vegetation to control erosion on the flatter portions of the site may be practicable in regions of the USA with sufficient rainfall and suitable soil types, but revegetation practices must be carefully evaluated to ensure that long

  1. Identification of chemical processes influencing constituent mobility during in-situ uranium leaching

    International Nuclear Information System (INIS)

    Sherwood, D.R.; Hostetler, C.J.; Deutsch, W.J.

    1984-07-01

    In-situ leaching of uranium has become a widely accepted method for production of uranium concentrate from ore zones that are too small, too deep, and/or too low in grade to be mined by conventional techniques. One major environmental concern that exists with in-situ leaching of uranium is the possible adverse effects mining might have on regional ground water quality. The leaching solution (lixiviant), which extracts uranium from the ore zone, might also mobilize other potential contaminants (As, Se, Mo, and SO 4 ) associated with uranium ore. Column experiments were performed to investigate the geochemical interactions between a lixiviant and a uranium ore during in-situ leaching and to identify chemical processes that might influence contaminant mobility. The analytical composition data for selected column effluents were used with the MINTEQ code to develop a computerized geochemical model of the system. MINTEQ was used to calculate saturation indices for solid phases based on the composition of the solution. A potential constraint on uranium leaching efficiency appears to be the solubility control of schoepite. Gypsum and powellite solubilities may limit the mobilities of sulfate and molybdenum, respectively. In contrast, the mobilities of arsenic and selenium were not limited by solubility constraints, but were influenced by other chemical interaction between the solution and sediment, perhaps adsorption. Bulk chemical and mineralogical analyses were performed on both the original and leached ores. Using these analyses together with the column effluent data, mass balance calculations were performed on five constituents based on solution chemical analysis and bulk chemical and γ-spectroscopy analysis for the sediment. 6 references, 10 figures, 10 tables

  2. Zero-valent iron nanoparticles in treatment of acid mine water from in situ uranium leaching.

    Science.gov (United States)

    Klimkova, Stepanka; Cernik, Miroslav; Lacinova, Lenka; Filip, Jan; Jancik, Dalibor; Zboril, Radek

    2011-02-01

    Acid mine water from in situ chemical leaching of uranium (Straz pod Ralskem, Czech Republic) was treated in laboratory scale experiments by zero-valent iron nanoparticles (nZVI). For the first time, nZVI were applied for the treatment of the real acid water system containing the miscellaneous mixture of pollutants, where the various removal mechanisms occur simultaneously. Toxicity of the treated saline acid water is caused by major contaminants represented by aluminum and sulphates in a high concentration, as well as by microcontaminants like As, Be, Cd, Cr, Cu, Ni, U, V, and Zn. Laboratory batch experiments proved a significant decrease in concentrations of all the monitored pollutants due to an increase in pH and a decrease in oxidation-reduction potential related to an application of nZVI. The assumed mechanisms of contaminants removal include precipitation of cations in a lower oxidation state, precipitation caused by a simple pH increase and co-precipitation with the formed iron oxyhydroxides. The possibility to control the reaction kinetics through the nature of the surface stabilizing shell (polymer vs. FeO nanolayer) is discussed as an important practical aspect. Copyright © 2010 Elsevier Ltd. All rights reserved.

  3. Economic evaluation of in situ extraction for copper, gold, and uranium

    International Nuclear Information System (INIS)

    Lewis, F.M.; Chase, C.K.; Bhappu, R.B.

    1976-01-01

    In situ extraction for copper, gold, and uranium, generally involves several common alternative processes and techniques. These include dump leaching, heap leaching, leaching of fractured ore in-place or bore hole mining and unit operations such as cementation, solvent extraction, ion-exchange, or carbon-in-pulp. Since the metallurgical effectiveness and economics of such processes and unit operations are well established, it would be possible to select the optimum alternative for extracting either copper, gold, or uranium from their ores using in situ extraction technology. Efforts made to provide metallurgical evaluation as well as capital and operating costs for the various processes and unit operations are reported. These costs are used in preparing feasibility studies for in situ extraction of these metals

  4. Stability with temperature of mixed uranium plutonium monocarbides

    International Nuclear Information System (INIS)

    Riglet-Martial, Ch.; Dumas, J.C.; Piron, J.P.; Gueneau, Ch.

    2008-01-01

    Full text: Among the different advanced fuel materials of concern for Generation IV systems, the mixed carbide of uranium and plutonium fuel is considered as one of the key materials for Gas Fast Reactors (GFR) systems. For purposes of optimising its fabrication process as well as its performances in various operating conditions, the losses of gaseous plutonium specially at elevated temperatures have to be controlled and minimized. The paper is therefore concerned with a parametric analysis of the stability with temperature of mixed carbides of uranium and plutonium. Previous published experimental studies have shown that mixed (U ,Pu) carbides undergo a highly incongruent sublimation at high temperatures: the vapour phase in equilibrium with the solid is mainly composed of gaseous plutonium (P Pu /P total > 99 % ) while the contribution of gaseous U and C remains very low. The composition of the system U 1-z Pu z C 1+x ' (z =Pu/(U+Pu) and x C/(U+Pu)), the temperature (T) and the expansion volume (V) of the gas are the main parameters in the loss of gaseous Pu. The calculations are carried out using the SAGE (Solgasmix Advanced Gibbs Energy) software, by assuming ideal solid solutions between UC and PuC, as well as between U 2 C 3 and Pu 2 C 3 . The validity of the model is previously tested using published equilibrium vapour pressure data. This work gives rise to a large description of the variations of Pu losses from mixed uranium plutonium carbides and leads to some basic recommendations in connection with the use of this advanced fuel materials

  5. Vegetational stabilization of uranium spoil areas, grants, New Mexico

    International Nuclear Information System (INIS)

    Kelley, N.E.

    1979-01-01

    Factors that could be detrimental to vegetative stabilization of uranium mine and mill waste material were examined. Physical and chemical analyses of materials from an open-pit uranium mine and material from three inactive mill tailing piles in New Mexico were performed. Analyses for selected trace elements in mill tailing material and associated vegetation from piles in New Mexico, Colorado, and Utah were also performed. Field and laboratory experiments identified problems associated with establishing vegetation on spoil material. Problems of uptake and concentration of toxic elements by plants growing on specific spoil material were also identified. Ecological observations in conjunction with physical and chemical analyses of specific geologic units, which form the overburden and waste dumps at the open-pit mine, identified a specific geologic material that, if segregated and placed on the surface of the dumps, would pose the least set of problems for a revegetation program. A pilot revegetation project verified that segregation and use of specific geologic material in the overburden could be utilized successfully and economically for reestablishment of native vegetation on mine waste material

  6. Waste water treatment of CO2+O2 in-situ leaching uranium

    International Nuclear Information System (INIS)

    Xu Lechang; Liu Naizhong; Du Zhiming; Wang Hongying

    2012-01-01

    An in-situ leaching uranium mine located in Northern China uses CO 2 +O 2 leaching process to leach uranium. The consumption of industrial reagent and water, and generation and discharge of waste water are minimized by comprehensive waste water treatment technology with process water recycle, reverse osmosis and natural evaporation. The process water of the mine that can be recycled and reused includes barren fluid, solution washing loaded resin, precipitating mother solution and filtered liquor of yellow cake. Solution regenerating barren resin is treated by reverse osmosis. Concentrated water from reverse osmosis and solution washing barren resin are naturally evaporated. (authors)

  7. Nitrification and in-situ uranium solution mining

    International Nuclear Information System (INIS)

    Johnson, D.; Humenick, M.J.

    1980-01-01

    The objective of this research was to determine the potential for conversion of ammonia to nitrate as a result of uranium solution mining operations. The work included literature evaluation and laboratory experimentation in both batch and continuous systems. Results indicate that a potential for nitrification could exist for some portions of the solution mining operating cycle. However, inhibition of nitrification was observed due to high ammonia and peroxide concentrations. Nitrification of ammonia also was observed to occur due to chemical oxidation by peroxide. 28 refs

  8. In situ carbonate leaching and recovery of uranium from ore deposits

    International Nuclear Information System (INIS)

    Hunkin, G.G.; Fife, T.P.; Stano, J.R.

    1979-01-01

    Uranium is leached from redox roll ore deposits by selective in-situ leaching with a solution of pH 7.4 to 9 (preferably 7.5 to 8.5) containing from about 0.5 to 5g/l of NH 4 HCO 3 and from about 0.1 to 3g/l of peroxide (preferably aqueous H 2 O 2 ), and sufficient NH 3 to maintain the desired pH. The leach solution is then withdrawn from the ore deposit and contacted with a strong base anion exchange material to strip the uranium from the leach solution. The uranium is eluted from the anion exchange material by an aqueous eluant, and the uranium is recovered from the eluate by first acidifying it and then treating it with ammonia to produce a precipitate of relatively pure ammonium diuranate. The content of the three components in the stripped leach solution is adjusted, and then the leach solution is recirculated through the ore deposit. After the uranium ore is removed to the extent economically practicable, the leach solution is replaced with an aqueous reducing solution which when passed into the ore deposit precipitates and renders insoluble any uranium and elements such as vanadium, molybdenum, and selenium. This process produces above ground a very low volume of impurities and waste solutions requiring disposal and does not cause material contamination of the underground deposit or any aquifer associated with the deposit

  9. Aquifer restoration at in-situ leach uranium mines: evidence for natural restoration processes

    International Nuclear Information System (INIS)

    Deutsch, W.J.; Serne, R.J.; Bell, N.E.; Martin, W.J.

    1983-04-01

    Pacific Northwest Laboratory conducted experiments with aquifer sediments and leaching solution (lixiviant) from an in-situ leach uranium mine. The data from these laboratory experiments and information on the normal distribution of elements associated with roll-front uranium deposits provide evidence that natural processes can enhance restoration of aquifers affected by leach mining. Our experiments show that the concentration of uranium (U) in solution can decrease at least an order of magnitude (from 50 to less than 5 ppM U) due to reactions between the lixiviant and sediment, and that a uranium solid, possibly amorphous uranium dioxide, (UO 2 ), can limit the concentration of uranium in a solution in contact with reduced sediment. The concentrations of As, Se, and Mo in an oxidizing lixiviant should also decrease as a result of redox and precipitation reactions between the solution and sediment. The lixiviant concentrations of major anions (chloride and sulfate) other than carbonate were not affected by short-term (less than one week) contact with the aquifer sediments. This is also true of the total dissolved solids level of the solution. Consequently, we recommend that these solution parameters be used as indicators of an excursion of leaching solution from the leach field. Our experiments have shown that natural aquifer processes can affect the solution concentration of certain constituents. This effect should be considered when guidelines for aquifer restoration are established

  10. Some implications of in situ uranium mining technology development

    International Nuclear Information System (INIS)

    Cowan, C.E.; Parkhurst, M.A.; Cole, R.J.; Keller, D.; Mellinger, P.J.; Wallace, R.W.

    1980-09-01

    The assessment indicates that there do not appear to be any significant demonstrated negative environmental impacts. Moreover, the impacts of in situ mining compare favorably with those impacts expected from conventional mining techniques. Exposure to radioactive elements is less, atmospheric emissions of radioactive and nonradioactive materials are generally less and socioeconomic impacts are decreased. In fact, because of the generally small and unskilled labor forces associated with in-situ mining, development has provided much needed economic stimulus to economically depressed areas of Texas. There are still, however, several areas of unknowns and several areas of inadequate information that will need to be addressed before a complete quantification evaluation of impacts can be made. These areas include levels of radon emissions and groundwater restoration methods and impacts. Several issues mostly relating to the interaction of industry with state and Federal regulators need to be addressed

  11. In situ vitrification: application analysis for stabilization of transuranic waste

    International Nuclear Information System (INIS)

    Oma, K.H.; Farnsworth, R.K.; Rusin, J.M.

    1982-09-01

    The in situ vitrification process builds upon the electric melter technology previously developed for high-level waste immobilization. In situ vitrification converts buried wastes and contaminated soil to an extremely durable glass and crystalline waste form by melting the materials, in place, using joule heating. Once the waste materials have been solidified, the high integrity waste form should not cause future ground subsidence. Environmental transport of the waste due to water or wind erosion, and plant or animal intrusion, is minimized. Environmental studies are currently being conducted to determine whether additional stabilization is required for certain in-ground transuranic waste sites. An applications analysis has been performed to identify several in situ vitrification process limitations which may exist at transuranic waste sites. Based on the process limit analysis, in situ vitrification is well suited for solidification of most in-ground transuranic wastes. The process is best suited for liquid disposal sites. A site-specific performance analysis, based on safety, health, environmental, and economic assessments, will be required to determine for which sites in situ vitrification is an acceptable disposal technique. Process economics of in situ vitrification compare favorably with other in-situ solidification processes and are an order of magnitude less than the costs for exhumation and disposal in a repository. Leachability of the vitrified product compares closely with that of Pyrex glass and is significantly better than granite, marble, or bottle glass. Total release to the environment from a vitrified waste site is estimated to be less than 10 -5 parts per year. 32 figures, 30 tables

  12. A economic evaluation system software on in-situ leaching mining sandstone uranium deposits

    International Nuclear Information System (INIS)

    Yao Yixuan; Su Xuebin; Xie Weixing; Que Weimin

    2001-01-01

    The author presents the study results of applying computer technology to evaluate quantitatively the technical-economic feasibility of in-situ leaching mining sandstone uranium deposits. A computer system software have been developed. Under specifying deposit conditions and given production size per year, the application of the software will generate total capital and mine life operating costs as well as solve for the movable and static financial assessment targets through discounted cash flow analysis. According to the characters of two kinds of sandstone uranium deposits, a data bases of economic and technique parameters of in-situ leaching have been designed. Also the system software can be used to study the economic value of deposits and to optimize the key project parameters. Its features, data input method and demand, main functions, structure and operating environments are described

  13. Modeling the migration of radioactive contaminants in groundwater of in situ leaching uranium mine

    International Nuclear Information System (INIS)

    Li Chunguang; Tai Kaixuan

    2011-01-01

    The radioactive contamination of groundwater from in situ leaching (ISL) of uranium mining is a widespread environmental problem. This paper analyzed the monitor results of groundwater contaminations for a in situ leaching uranium mine. A dynamic model of contaminants transport in groundwater in ISL well field was established. The processes and mechanisms of contaminant transport in groundwater were simulated numerically for a ISL well field. A small quantity of U and SO 4 2- migrate to outside of well field during ISL production stage. But the migration velocity and distance of contaminations is small, and the concentration is low. Contaminants migrate as anomalistic tooth-shape. The migration trend of U and SO 4 2- is consistent. Numerical modeling can provide an effective approach to analyse the transport mechanism, and forecast and control the migration of contaminants in groundwater in ISL well field. (authors)

  14. Execution of pilot tests for an uranium in situ leaching project

    International Nuclear Information System (INIS)

    Koch, H.J.

    1983-01-01

    Urangesellschaft is presently evaluating the technical and economic feasibility of an in situ leaching (ISL) project in Wyoming/USA. This report describes the basic technical principles for ISL-uranium projects and gives the reasons for conducting pilot tests prior to the construction of a commercial plant. It further describes the licensing requirements for an ISL-pilot plant and evaluates the results of the pilot tests. (orig.) [de

  15. Geochemical model of uranium and selenium in an aquifer disturbed by in situ uranium mining

    International Nuclear Information System (INIS)

    Johnson, K.; Neumann, M.R.

    1986-01-01

    Restoring ground water to baseline conditions proved to be very difficult, however, and led to the trial of a sodium carbonate/bicarbonate lixiviant. Results of this test indicated the basic lixiviant was unable to address uranium tied up in carbonaceous material. Subsequently, the decision was made to curtail development and restore all affected ground water to the extent achievable through the use of the best practicable technology, such as reverse osmosis. Restoration results, however, were not considered adequate for demonstration of commercial restoration feasibility. Following completion of the restoration effort, regulatory agencies expressed concern as to the long-term fate of certain parameters, such as uranium and selenium, remaining in solution at above baseline levels. Rocky Mountain Energy, through discussions with various consultants, determined that geochemical modeling would be the most appropriate tool for predicting the probable long-term effects. This paper summarizes the results of the subsequent evaluation which was conducted using the PHREEQE computer model. Significant conclusions of the investigation were: (1) the Eh in the ground water decreases regularly after mining activities, as shown by measured Eh values, and (2) the accompanying decrease in uranium and selenium can be predicted by thermodynamic modeling

  16. In situ leach uranium mining. Proceedings of a technical committee meeting. Working material

    International Nuclear Information System (INIS)

    2002-03-01

    At the beginning of 1996 there were 437 nuclear power plants in operation with a combined electricity generating capacity of 344 GWe (net gigawatts electric). This represents nearly a 100% increase over the last decade. In 1995 over 2228 TWh (terawatt hours) electricity were generated, equivalent to about 17% of the world's total electricity. To achieve this, about 61 400 tonnes U were required as nuclear fuel. The 15 year decline of the spot uranium price, as indicated by Nuexco Exchange Value (NEV) and other indices, which reached an all time low annual average in 1994 of $18.33/kg U ($7.05/pound U 3 O 8 ), has had a profound impact on uranium related activities. This led to the massive reduction and realignment of all uranium related activities as the worldwide uranium market adjusted from over-production. Because of the economic advantages of properly run in situ leach technology on carefully selected uranium orebodies, relatively more ISL mining facilities have been kept in operation than conventional mining operations. In 1995 world uranium production of about 34 000 t uranium met only about 55% of world requirements. An estimated 16% of production came from ISL mining. In 1996 ISL mining was estimated to have produced over 5600 tU, or over 15% of estimated world production of 36 400 tU. The importance of ISL mining is expected to increase, as the technology has economic and environmental advantages for producing uranium from carefully selected deposits when projects are properly designed and operated by experienced personnel. Several countries host sandstone type uranium deposits, the only type where commercial ISL projects have been developed. ISL uranium mining technology was developed independently in the USA and the former Soviet Union and associated non-WOCA (world outside centrally planned economic areas) countries starting in the 1960s and 1970s. Since the opening of relations between the two areas in the early 1990s there has been a high level of

  17. Cross-check of ex-situ and in-situ metrology of a bendable temperature stabilized KB mirror

    International Nuclear Information System (INIS)

    Yuan Sheng; Goldberg, Kenneth A.; Yashchuk, Valeriy V.; Celestre, Richard; McKinney, Wayne R.; Morrison, Gregory; Macdougall, James; Mochi, Iacopo; Warwick, Tony

    2011-01-01

    At the Advanced Light Source (ALS), we are developing broadly applicable, high-accuracy, in-situ, at-wavelength wavefront slope measurement techniques for Kirkpatrick-Baez (KB) mirror nano-focusing. In this paper, we report an initial cross-check of ex-situ and in-situ metrology of a bendable temperature stabilized KB mirror. This cross-check provides a validation of the in-situ shearing interferometry, currently under development at the ALS.

  18. Recovering uranium from coal in-situ. Final report, February 1980-July 1981

    International Nuclear Information System (INIS)

    1981-01-01

    In Situ Technology, Inc., ''InTech,'' has designed a new process for recovery of uranium from coal in situ. Prime objectives of the program reported herein are to reduce two uncertainties related to eventual commercialization of the process. The first uncertainty concerns appropriate field sites and their potential. The work involved laboratory tests and analysis of field samples, burning the samples to ash and leaching uranium from residual ash at laboratory scale, and burning the samples to ash and leaching uranium from residual ash at pilot plant scale. Laboratory and pilot plant tests were designed to simulate significant elements of the underground process. Field samples from New Mexico averaged 0.061% U 3 O 8 and from North Dakota 0.058% of U 3 O 8 in the coal, both on a dry basis. Phase I laboratory tests on New Mexico field samples were successfully conducted with no difficulties in reducing uraniferous coal to ash. Leaching tests resulted in uranium recoveries to 77.9% with acid leach and to 56% with alkaline leach. Phase II laboratory and pilot plant scale tests were successfully conducted on North Dakota field samples, but required supplemental fuel and/or enrichment for reducing uraniferous coal to ash. Acid leaching of residual ash resulted in uranium recoveries to 83.8%. Acid consumption was 71.0 pounds per ton during pilot plant scale leaching tests. The overall analysis and test program is considered to be highly successful and resulted in significant reduction of the uncertainties for eventual commercialization of the process. 3 refs

  19. The design on high slope stabilization in waste rock sites of uranium mines

    International Nuclear Information System (INIS)

    Liu Taoan; Zhou Xinghuo; Liu Jia

    2005-01-01

    Design methods, reinforcement measures, and flood control measures concerning high slope stabilization in harnessing waste rock site are described in brief according to some examples of two uranium mines in Hunan province. (authors)

  20. Irradiation Stability of Uranium Alloys at High Exposures

    International Nuclear Information System (INIS)

    McDonell, W.R.

    2001-01-01

    Postirradiation examinations were begun of a series of unrestrained dilute uranium alloy specimens irradiated to exposures up to 13,000 MWD/T in NaK-containing stainless steel capsules. This test, part of a program of development of uranium metal fuels for desalination and power reactors sponsored by the Division of Reactor Development and Technology, has the objective of defining the temperature and exposure limits of swelling resistance of the alloyed uranium. This paper discusses those test results

  1. Direct current stabilization of scintillation counters used for uranium prospecting

    International Nuclear Information System (INIS)

    Fraser, H.J.

    1976-01-01

    A simple system for stabilizing a scintillation counter is described which uses a dc light source (a green light emitting diode) to illuminate the photo-cathode of the photomultiplier used to detect γ-induced light pulses from the scintillator. Basically, the photomultiplier anode current due to the light emitting diode light is held constant by an automatic control loop acting on the eht voltage to keep the gain of the photomultiplier tube constant. However, because the temperature coefficient of the scintillator does not in general match that of the light emitting diode, further compensation is required to achieve constant γ pulse gain. This is provided by adding to the control circuit a current derived from the light emitting diode voltage which is an excellent measure of temperature; the use of this technique results in gain constancy to within +-1% in the 10-50 0 C ambient temperature range. Noise and countrate limitations are discussed and it is concluded that the system is generally applicable to uranium prospecting equipment. (Auth.)

  2. Estimating contaminant discharge rates from stabilized uranium tailings embankments

    International Nuclear Information System (INIS)

    Weber, M.F.

    1986-01-01

    Estimates of contaminant discharge rates from stabilized uranium tailings embankments are essential in evaluating long-term impacts of tailings disposal on groundwater resources. Contaminant discharge rates are a function of water flux through tailings covers, the mass and distribution of tailings, and the concentrations of contaminants in percolating pore fluids. Simple calculations, laboratory and field testing, and analytical and numerical modeling may be used to estimate water flux through variably-saturated tailings under steady-state conditions, which develop after consolidation and dewatering have essentially ceased. Contaminant concentrations in water discharging from the tailings depend on tailings composition, leachability and solubility of contaminants, geochemical conditions within the embankment, tailings-water interactions, and flux of water through the embankment. These concentrations may be estimated based on maximum reported concentrations, pore water concentrations, extrapolations of column leaching data, or geochemical equilibria and reaction pathway modeling. Attempts to estimate contaminant discharge rates should begin with simple, conservative calculations and progress to more-complicated approaches, as necessary

  3. Study on U-Ra equilibrium coefficient of the in-situ leaching sandstone-type uranium deposits: A case study of Qianjiadian uranium deposit

    International Nuclear Information System (INIS)

    Xia Yuliang; Xiu Qunye; Han Jun; Li Linqiang; Zheng Jiwei

    2013-01-01

    This paper investigated the U-Ra equilibrium coefficient (K-p) of mineralized sandstone and mudstone, and unmineralized sandstone and mudstone for the in-situ leaching sandstone-type uranium deposits. It is surprised that all of the mineralized sandstone and mudstone are both relatively to be partial to uranium, but all of the unmineralized sandstone and mudstone are both relatively to be partial to radium. Meanwhile the uranium in mineralized mudstone is relatively richer than that in mineralized sandstone, and the radium in unmineralized mudstone is relatively richer than that in unmineralized sandstone. It is suggested that mudstones were permeable at the uranium mineralized phase and the unmineralized mudstone and sandstone could serve as important mineralized uranium source. (authors)

  4. Issues on management, stabilization and environmental impacts of uranium mill tailings

    International Nuclear Information System (INIS)

    Cunningham, R.E.

    1978-01-01

    Management and stabilization of uranium mill tailings has been controversial for over two decades. There are two basic issues: the nature of the risk to the public from tailings and what must be done to mitigate that risk. This paper provides an overview of the issues and sets some goals to be accomplished at the 1978 NEA Seminar on Management, Stabilization and Environmental Impacts of Uranium Mill Tailings that could be helpful in resolving the issues

  5. Quantification of the effect of in-situ generated uranium metal on the experimentally determined O/U ratio of a sintered uranium dioxide fuel pellet

    International Nuclear Information System (INIS)

    Narasimha Murty, B.; Bharati Misra, U.; Yadav, R.B.; Srivastava, R.K.

    2005-01-01

    This paper describes quantitatively the effect of in-situ generated uranium metal (that could be formed due to the conducive manufacturing conditions) in a sintered uranium dioxide fuel pellet on the experimentally determined O/U ratio using analytical methods involving dissolution of the pellet material. To quantify the effect of in-situ generated uranium metal in the fuel pellet, a mathematical expression is derived for the actual O/U ratio in terms of the O/U ratio as determined by an experiment involving dissolution of the material and the quantity of uranium metal present in the uranium dioxide pellet. The utility of this derived mathematical expression is demonstrated by tabulating the calculated actual O/U ratios for varying amounts of uranium metal (from 5 to 95% in 5% intervals) and different O/U ratio values (from 2.001 to 2.015 in 0.001 intervals). This paper brings out the necessity of care to be exercised while interpreting the experimentally determined O/U ratio and emphasizes the fact that it is always safer to produce the nuclear fuel with oxygen to uranium ratios well below the specified maximum limit of 2.015. (author)

  6. Experimental study and numerical modelling of geochemical reactions occurring during uranium in situ recovery (ISR) mining

    International Nuclear Information System (INIS)

    Ben Simon, R.

    2011-09-01

    The in situ Recovery (ISR) method consists of ore mining by in situ chemical leaching with acid or alkaline solutions. ISR takes place underground and is therefore limited to the analysis of the pumped solutions, hence ISR mine management is still empirical. Numerical modelling has been considered to achieve more efficient management of this process. Three different phenomena have to be taken into account for numerical simulations of uranium ISR mining: (1) geochemical reactions; (2) the kinetics of these reactions, and (3) hydrodynamic transport with respect to the reaction kinetics. Leaching tests have been conducted on ore samples from an uranium mine in Tortkuduk (Kazakhstan) where ISR is conducted by acid leaching. Two types of leaching experiments were performed: (1) tests in batch reactors; and (2) extraction in flow through columns. The assumptions deduced from the leaching tests were tested and validated by modelling the laboratory experiments with the numerical codes CHESS and HYTEC, both developed at the Geosciences research center of Mines ParisTech. A well-constrained 1D hydrogeochemical transport model of the ISR process at laboratory-scale was proposed. It enables to translate the chemical release sequence that is observed during experiments into a geochemical reaction sequence. It was possible to highlight the controlling factors of uranium dissolution, and the precipitation of secondary mineral phase in the deposit, as well as the determination of the relative importance of these factors. (author)

  7. Laboratory studies on natural restoration of ground water after in-situ leach uranium mining

    International Nuclear Information System (INIS)

    Bell, N.E.; Deutsch, W.J.; Serne, R.J.

    1983-05-01

    When uranium is mined using in-situ leach techniques, the chemical quality of the ground water in the ore-zone aquifer is affected. This could lead to long-term degradation of the ground water if restoration techniques are not applied after the leaching is completed. Pacific Northwest Laboratory (PNL), is conducting an NRC-sponsored research project on natural restoration and induced-restoration techniques. Laboratory studies were designed to evaluate the ability of the natural system (ore-zone sediments and groundwater) to mitigate the effects of mining on aquifer chemistry. Using batch and flow-through column experiments [performed with lixiviant (leaching solution) and sediments from the reduced zone of an ore-zone aquifer], we found that the natural system can lower uranium and bicarbonate concentrations in solutions and reduce the lixiviant redox potential (Eh). The change in redox potential could cause some of the contaminants that were dissolved during the uranium leaching operation to precipitate, thereby lowering their solution concentration. The concentrations of other species such as calcium, potassium, and sulfate increased, possibly as a result of mineral dissolution and ion exchange. In this paper, we describe the experimentally determined mobility of contaminants after in-situ leach mining, and discuss the possible chemical process affecting mobility

  8. Laboratory studies on natural restoration of ground water after in-situ leach uranium mining

    Energy Technology Data Exchange (ETDEWEB)

    Bell, N.E.; Deutsch, W.J.; Serne, R.J.

    1983-05-01

    When uranium is mined using in-situ leach techniques, the chemical quality of the ground water in the ore-zone aquifer is affected. This could lead to long-term degradation of the ground water if restoration techniques are not applied after the leaching is completed. Pacific Northwest Laboratory (PNL), is conducting an NRC-sponsored research project on natural restoration and induced-restoration techniques. Laboratory studies were designed to evaluate the ability of the natural system (ore-zone sediments and groundwater) to mitigate the effects of mining on aquifer chemistry. Using batch and flow-through column experiments (performed with lixiviant (leaching solution) and sediments from the reduced zone of an ore-zone aquifer), we found that the natural system can lower uranium and bicarbonate concentrations in solutions and reduce the lixiviant redox potential (Eh). The change in redox potential could cause some of the contaminants that were dissolved during the uranium leaching operation to precipitate, thereby lowering their solution concentration. The concentrations of other species such as calcium, potassium, and sulfate increased, possibly as a result of mineral dissolution and ion exchange. In this paper, we describe the experimentally determined mobility of contaminants after in-situ leach mining, and discuss the possible chemical process affecting mobility.

  9. Uranium Mobility During In Situ Redox Manipulation of the 100 Areas of the Hanford Site

    International Nuclear Information System (INIS)

    Resch, C.T.; Szecsody, J.E.; Fruchter, J.S.; Cantrell, K.J.; Krupka, K.M.; Williams, M.D.

    1998-01-01

    A series of laboratory experiments and computer simulations was conducted to assess the extent of uranium remobilization that is likely to occur at the end of the life cycle of an in situ sediment reduction process. The process is being tested for subsurface remediation of chromate- and chlorinated solvent-contaminated sediments at the Hanford Site in southeastern Washington. Uranium species that occur naturally in the +6 valence state ∼(VI) at 10 ppb in groundwater at Hanford will accumulate as U(N) through the reduction and subsequent precipitation conditions of the permeable barrier created by in situ redox manipulation. The precipitated uranium will W remobilized when the reductive capacity of the barrier is exhausted and the sediment is oxidized by the groundwater containing dissolved oxygen and other oxidants such as chromate. Although U(N) accumulates from years or decades of reduction/precipitation within the reduced zone, U(W) concentrations in solution are only somewhat elevated during aquifer oxidation because oxidation and dissolution reactions that release U(N) precipitate to solution are slow. The release rate of uranium into solution was found to be controlled mainly by the oxidation/dissolution rate of the U(IV) precipitate (half-life 200 hours) and partially by the fast oxidation of adsorbed Fe(II) (half- life 5 hours) and the slow oxidation of Fe(II)CO 3 (half-life 120 hours) in the reduced sediment. Simulations of uranium transport that incorporated these and other reactions under site-relevant conditions indicated that 35 ppb U(VI) is the maximum concentration likely to result from mobilization of the precipitated U(IV) species. Experiments also indicated that increasing the contact time between the U(IV) precipitates and the reduced sediment, which is likely to occur in the field, results in a slower U(IV) oxidation rate, which, in turn, would lower the maximum concentration of mobilized U(W). A six-month-long column experiment confirmed that

  10. In situ stabilization wall for containment and hot spot retrieval

    International Nuclear Information System (INIS)

    Loomis, G.G.

    1996-01-01

    This paper presents the results of a full scale field demonstration of a in situ stabilization technology applicable to buried transuranic waste. The technology involves creating a jet grouted wall around selected regions or hot spots within a buried waste site. The resulting wall provides a barrier against further horizontal migration of the contaminants and allows vertical digging of material inside the wall, thus minimizing waste during a hot spot removal action. The demonstration involved creating a open-quotes Uclose quotes shaped wall in the interior of a full sized, simulated waste pit. The wall simulated the main features of a four sided wall. The demonstration also involved a destructive examination and a stability test for a hot spot retrieval scenario

  11. Factoring uncertainty into restoration modeling of in-situ leach uranium mines

    Science.gov (United States)

    Johnson, Raymond H.; Friedel, Michael J.

    2009-01-01

    Postmining restoration is one of the greatest concerns for uranium in-situ leach (ISL) mining operations. The ISL-affected aquifer needs to be returned to conditions specified in the mining permit (either premining or other specified conditions). When uranium ISL operations are completed, postmining restoration is usually achieved by injecting reducing agents into the mined zone. The objective of this process is to restore the aquifer to premining conditions by reducing the solubility of uranium and other metals in the ground water. Reactive transport modeling is a potentially useful method for simulating the effectiveness of proposed restoration techniques. While reactive transport models can be useful, they are a simplification of reality that introduces uncertainty through the model conceptualization, parameterization, and calibration processes. For this reason, quantifying the uncertainty in simulated temporal and spatial hydrogeochemistry is important for postremedial risk evaluation of metal concentrations and mobility. Quantifying the range of uncertainty in key predictions (such as uranium concentrations at a specific location) can be achieved using forward Monte Carlo or other inverse modeling techniques (trial-and-error parameter sensitivity, calibration constrained Monte Carlo). These techniques provide simulated values of metal concentrations at specified locations that can be presented as nonlinear uncertainty limits or probability density functions. Decisionmakers can use these results to better evaluate environmental risk as future metal concentrations with a limited range of possibilities, based on a scientific evaluation of uncertainty.

  12. In-situ stabilization of mixed waste contaminated soil

    International Nuclear Information System (INIS)

    Siegrist, R.L.; Cline, S.R.; Gilliam, T.M.; Conner, J.R.

    1993-01-01

    A full-scale field demonstration was conducted to evaluate in for stabilizing an inactive RCRA land treatment site at a DOE facility in Ohio. Subsurface silt and clay deposits were contaminated principally with up to 500 mg/kg of trichloroethylene and other halocarbons, but also trace to low levels of Pb, Cr, 235 U, and 99 Tc. In situ solidification was studied in three, 3.1 m diameter by 4.6 m deep columns. During mixing, a cement-based grout was injected and any missions from the mixed region were captured in a shroud and treated by filtration and carbon adsorption. During in situ processing, operation and performance parameters were measured, and soil cores were obtained from a solidified column 15 months later. Despite previous site-specific treatability experience, there were difficulties in selecting a grout with the requisite treatment agents amenable to subsurface injection and at a volume adequate for distribution throughout the mixed region while minimizing volume expansion. observations during the demonstration revealed that in situ solidification was rapidly accomplished (e.g., >90 m 3 /d) with limited emissions of volatile organics (i.e., -6 cm/s vs. 10 -8 cm/s). Leaching tests performed on the treated samples revealed non-detectable to acceptably low concentrations of all target contaminants

  13. The theory and method of two-well field test for in-situ leaching uranium

    International Nuclear Information System (INIS)

    Yao Yixuan; Huo Jiandang; Xiang Qiulin; Tang Baobin

    2007-01-01

    Because leaching area in field test for in-situ leaching uranium is not accounted exactly, the reliability of obtaining parameters by calculating can not be ensured, and the whole test needs a long time and great investment. In two-well field test, lixiviant is injected from one well, pregnant solution is pumped out from the other, flow rate of the production well is more than that of the injection well, and uranium is not recoveried. In the case of keeping invariable ratio of pumping capacity to injecting capacity during the testing process, leaching area is not variable, can be exactly calculated. The full field test needs six months to one year. Two-well test is a scientific, rapid, minimal spending field test method, and is widely used in Commonwealth of Independent States. (authors)

  14. Experience with restoration of ore-bearing aquifers after in situ leach uranium mining

    International Nuclear Information System (INIS)

    Yazikov, V.G.; Zabaznov, V.U.

    2002-01-01

    In many cases the most important environmental issue for in situ leach uranium mining technology is the impact on groundwater. Usually the greatest issue is the chemical condition of the ore bearing aquifer following the completion of leaching. Based on experience gained during post leach monitoring, it has been found that in properly selected sites the impact following leaching is greatly reduced because of the process of self restoration, otherwise known as natural attenuation. This paper provides ground water monitoring data from 1985 to 1997 following completion of leaching at the Irkol uranium deposit, Kazakhstan. It shows the evolution of the pH, and other chemical parameters over this period. The monitoring results demonstrate that at this site the process of natural attenuation appears to have effectively reduced the impact on groundwater at the site, as well as to keep contaminated leaching fluids from moving more than a few hundreds of metres from the wellfield. (author)

  15. Streamline-concentration balance model for in-situ uranium leaching and site restoration

    International Nuclear Information System (INIS)

    Bommer, P.M.; Schechter, R.S.; Humenick, M.J.

    1981-03-01

    This work presents two computer models. One describes in-situ uranium leaching and the other describes post leaching site restoration. Both models use a streamline generator to set up the flow field over the reservoir. The leaching model then uses the flow data in a concentration balance along each streamline coupled with the appropriate reaction kinetics to calculate uranium production. The restoration model uses the same procedure except that binary cation exchange is used as the restoring mechanism along each streamline and leaching cation clean up is simulated. The mathematical basis for each model is shown in detail along with the computational schemes used. Finally, the two models have been used with several data sets to point out their capabilities and to illustrate important leaching and restoration parameters and schemes

  16. In situ production of 36CI in uranium ore: a hydrogeological assessment tool

    International Nuclear Information System (INIS)

    Cornett, R.J.; Cramer, J.; Andrews, H.R.; Chant, L.A.; Davies, W.; Greiner, B.F.; Imahori, Y.; Koslowsky, V.; McKay, J.; Milton, G.M.; Milton, J.C.D.

    1996-01-01

    In situ neutron activation of 35 Cl within the rock and groundwater of geologic deposits that have elevated concentrations of uranium provides a hydrogeological tracer. We determine the production rate and mobility of 36 Cl in the 1.3-billion-year-old Cigar Lake uranium ore deposit. Accelerator mass spectrometry was used to map the Concentrations of 36 Cl in the ore and in the groundwater that were up to 100 times greater than those encountered in unmineralized portions of the host sandstone aquifer. The residence time of this mobile anion in groundwater within the mineralized zone ranged from 14 to 280 kyr. These residence times are consistent with the hydraulic and geochemical data, suggesting significant control of Cl - and groundwater movement by the clay-rich matrix of the mineralized zone. (author)

  17. Streamline-concentration balance model for in situ uranium leaching and site restoration

    International Nuclear Information System (INIS)

    Bommer, P.M.

    1979-01-01

    This work presents two computer models. One describes in situ uranium leaching and the other describes post leaching site restoration. Both models use a streamline generator to set up the flow field over the reservoir. The leaching model then uses the flow data in a concentration balance along each streamline coupled with the appropriate reaction kinetics to calculate uranium production. The restoration model uses the same procedure ecept that binary cation exchange is used as the restoring mechanism along each streamline and leaching cation clean up is stimulated. The mathematical basis for each model is shown in detail along with the computational schemes used. Finally, the two models have been used with several data sets to point out their capabilities and to illustrate important leaching and restoration parameters and schemes

  18. Stabilization of contaminated soils by in situ vitrification

    International Nuclear Information System (INIS)

    Timmerman, C.L.

    1984-01-01

    In Situ Vitrification is an emerging technology developed by Pacific Northwest Laboratory for potential in-place immobilization of radioactive wastes. The contaminated soil is stabilized and converted to an inert glass form. This conversion is accomplished by inserting electrodes in the soil and establishing an electric current between the electrodes. The electrical energy causes a joule heating effect that melts the soil during processing. Any contaminants released from the melt are collected and routed to an off-gas treatment system. A stable and durable glass block is produced which chemically and physically encapsulates any residual waste components. In situ vitrification has been developed for the potential application to radioactive wastes, specifically, contaminated soil sites; however, it could possibly be applied to hazardous chemical and buried munitions waste sites. The technology has been developed and demonstrated to date through a series of 21 engineering-scale tests [producing 50 to 1000 kg (100 to 2000 lb) blocks] and seven pilot-scale tests [producing 9000 kg (20,000 lb) blocks], the most recent of which illustrated treatment of actual radioactively contaminated soil. Testing with some organic materials has shown relatively complete thermal destruction and incineration. Further experiments have documented the insensitivity of in situ vitrification to soil characteristics such as fusion temperature, specific heat, thermal conductivity, electrical resistivity, and moisture content. Soil inclusions such as metals, cements, ceramics, and combustibles normally present only minor process limitations. Costs for hazardous waste applications are estimated to be less than $175/m 3 ($5.00/ft 3 ) of material vitrified. For many applications, in situ vitrification can provide a cost-effective alternative to other disposal options. 13 references, 4 figures, 1 table

  19. The computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in Northern Xinjiang, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhengbang, Wang; Mingkuan, Qin; Ruiquan, Zhao; Shenghuang, Tang [Beijing Research Inst. of Uranium Geology, CNNC (China); Baoqun, Wang; Shuangxing, Lin [Geo-prospecting Team No. 216, CNNC (China)

    2001-08-01

    The process of establishment of the model includes following steps: (1) Systematically studying a known typical in-situ leachable sandstone type uranium deposit--Deposit No. 512 in Yili basin, analyzing its controlling factors and establishing its metallogenetic model; (2) Establishing the metallogenetic models of this type of uranium deposit and uranium-bearing area on the basis of comparison study on the deposit No. 512 with the same type uranium deposits in the world; (3) Creating the computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in northern Xinjiang; (4) Determining the standards of giving a evaluation-mark for each controlling factor of in-situ leachable sandstone type uranium deposit and uranium-bearing area; (5) Evaluating uranium potential and prospect of the unknown objective target.

  20. The computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in Northern Xinjiang, China

    International Nuclear Information System (INIS)

    Wang Zhengbang; Qin Mingkuan; Zhao Ruiquan; Tang Shenghuang; Wang Baoqun; Lin Shuangxing

    2001-01-01

    The process of establishment of the model includes following steps: (1) Systematically studying a known typical in-situ leachable sandstone type uranium deposit--Deposit No. 512 in Yili basin, analyzing its controlling factors and establishing its metallogenetic model; (2) Establishing the metallogenetic models of this type of uranium deposit and uranium-bearing area on the basis of comparison study on the deposit No. 512 with the same type uranium deposits in the world; (3) Creating the computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in northern Xinjiang; (4) Determining the standards of giving a evaluation-mark for each controlling factor of in-situ leachable sandstone type uranium deposit and uranium-bearing area; (5) Evaluating uranium potential and prospect of the unknown objective target

  1. Recent developments in uranium resources and production with emphasis on in situ leach mining. Proceedings of a technical meeting

    International Nuclear Information System (INIS)

    2004-06-01

    An important role of the International Atomic Energy Agency is establishing contacts between Member States in order to foster the exchange of scientific and technical information on uranium production technologies. In situ leach (ISL) mining is defined as, the extraction of uranium from the host sandstone by chemical solutions and the recovery of uranium at the surface. ISL extraction is conducted by injecting a suitable leach solution into the ore zone below the water table; oxidizing, complexing, and mobilizing the uranium; recovering the pregnant solutions through production wells; and, finally, pumping the uranium bearing solution to the surface for further processing. As compared with conventional mining, in situ leach is recognized as having economic and environmental advantages when properly employed by knowledgeable specialists to extract uranium from suitable sandstone type deposits. Despite its limited applicability to specific types of uranium deposits, in recent years ISL uranium mining has been producing 15 to 21 per cent of world output. In 2002, ISL production was achieved in Australia, China, Kazakhstan, the United States of America and Uzbekistan. Its importance is expected to increase with new projects in Australia, China, Kazakhstan and the Russian Federation. The Technical Meeting on Recent Development in Uranium Resources and Production with Special Emphasis on In Situ Leach Mining, was held in Beijing from 18 to 20 September 2002, followed by the visit of the Yili ISL mine, Xinjiang Autonomous Region, China, from 21 to 23 September 2002. The meeting, held in cooperation with the Bureau of Geology, China National Nuclear Cooperation, was successful in bringing together 59 specialists representing 18 member states and one international organization (OECD/Nuclear Energy Agency). The papers describe a wide variety of activities related to the theme of the meeting. Subjects such as geology, resources evaluation, licensing, and mine restoration were

  2. Mapping of depleted uranium with in situ spectrometry and soil samples

    International Nuclear Information System (INIS)

    Shebell, P.; Reginatto, M.; Monetti, M.; Faller, S.; Davis, L.

    1999-01-01

    Depleted uranium (DU) has been developed in the past two decades as a highly effective material for armor penetrating rounds and vehicle shielding. There is now a growing interest in the defense community to determine the presence and extent of DU contamination quickly and with a minimum amount of intrusive sampling. We report on a new approach using deconvolution techniques to quantitatively map DU contamination in surface soil. This approach combines data from soil samples with data from in situ gamma-ray spectrometry measurements to produce an accurate and detailed map of DU contamination. Results of a field survey at the Aberdeen Proving Ground are presented. (author)

  3. Uranium

    International Nuclear Information System (INIS)

    Hamdoun, N.A.

    2007-01-01

    The article includes a historical preface about uranium, discovery of portability of sequential fission of uranium, uranium existence, basic raw materials, secondary raw materials, uranium's physical and chemical properties, uranium extraction, nuclear fuel cycle, logistics and estimation of the amount of uranium reserves, producing countries of concentrated uranium oxides and percentage of the world's total production, civilian and military uses of uranium. The use of depleted uranium in the Gulf War, the Balkans and Iraq has caused political and environmental effects which are complex, raising problems and questions about the effects that nuclear compounds left on human health and environment.

  4. In-situ containment and stabilization of buried waste

    International Nuclear Information System (INIS)

    Allan, M.L.; Kukacka, L.E.

    1993-10-01

    In FY 1993 research continued on development and testing of grout materials for in-situ containment and stabilization of buried waste. Specifically, the work was aimed at remediation of the Chemical Waste Landfill (CWL) at Sandia National Laboratories (SNL) in Albuquerque, New Mexico as part of the Mixed Waste Landfill Integrated Demonstration (MWLID). The work on grouting materials was initiated in FY 1992 and the accomplishments for that year are documented in the previous annual report (Allan, Kukacka and Heiser, 1992). The remediation plan involves stabilization of the chromium plume, placement of impermeable vertical and horizontal barriers to isolate the landfill and installation of a surface cap. The required depth of subsurface barriers is approximately 33 m (100 ft). The work concentrated on optimization of grout formulations for use as grout and soil cement barriers and caps. The durability of such materials was investigated, in addition to shrinkage cracking resistance, compressive and flexural strength and permeability. The potential for using fibers in grouts to control cracking was studied. Small scale field trials were conducted to test the practicality of using the identified formulations and to measure the long term performance. Large scale trials were conducted at Sandia as part of the Subsurface Barrier Emplacement Technology Program. Since it was already determined in FY 1992 that cementitious grouts could effectively stabilize the chromium plume at the CWL after pre-treatment is performed, the majority of the work was devoted to the containment aspect

  5. Licensing Status of New and Expanding In-Situ Recovery Uranium Projects in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Catchpole, G.; Thomas, M., E-mail: gccatchpole@uranerz.com [Uranerz Energy Corporation (URZ), Casper, WY (United States)

    2014-05-15

    The authors investigated the licensing status of new in-situ recovery (“ISR”) uranium projects, as well as the expansion of existing projects, within the United States (“US”). Specific emphasis and analysis is placed on those projects within the states of Texas and Wyoming. Of note, information used to prepare this paper was obtained from public sources that included company web sites, the US Securities and Exchange Commission, the US Nuclear Regulatory Commission (“NRC”), the US Energy Information Agency (“EIA”), and the relevant state regulatory agencies. The renewed interest in the production of natural uranium has been motivated, in part, by the increased sale price of yellowcake beginning around 2003 resulting in numerous new and existing natural resources companies acquiring mineral rights in the United States. Because of the economic favorability in terms of both operating and capital costs of ISR mines versus conventional mines in the US (with its relatively low grade of uranium ore), the model for most companies was to acquire mineral properties that had the potential for being mined using the ISR method. There were, however, exceptions to this model. The Uravan mineral district in southwest Colorado and southeast Utah, where relatively high-grade, shallow uranium deposits have the potential to be mined using underground methods, is one such exception. However, the focus of this paper will be on ISR projects. In Wyoming, which has been the top producer of natural uranium among the 50 states for the past seven years, there is one producing ISR mine (Bill Smith — Highland), one ISR mine on standby (Christensen Ranch), and two ISR uranium projects licensed but not yet built (Gas Hills and North Butte). Cameco Resources is planning to develop two ISR projects in Wyoming that have been licensed but not yet constructed. Additionally, three new uranium companies (Ur-Energy, Uranerz and Uranium One) have filed applications with the federal and

  6. The Honeymoon project: Australia`s first in situ leach uranium project

    Energy Technology Data Exchange (ETDEWEB)

    Ackland, M.C. [Southern Cross Resources Inc. Toowond, QLD (Australia)

    1997-12-31

    The Honeymoon uranium deposit is one of several roll front uranium deposits in South Australia. It was discovered in 1971, the project developed in the 1970`s, and was ready for demonstration of the In Situ Leaching (ISL) production techniques by January 1983, when the project was stopped, despite it having met the environmental approvals to proceed, due to the Australian Labour Party`s `three mines policy`. From 1983 until March 1996 the project was mothballed. In late 1996 Southern Cross Resources Inc. (SCRI) reached agreement with Mount Isa Mining (MIM) to purchase its uranium interests in Honeymoon, Goulds Dam and EL 2310 whilst simultaneously acquiring Sedimentary Holdings NL`s interests in EL 2310. By April 1997 these interests were consolidated in SCRI`s wholly owned subsidiary, Southern Cross Resources Australia Ply Ltd which is the operating company. Activities are presently underway to rehabilitate the existing treatment plant and continue the program that was outlined in the approved 1981 Honeymoon Environmental Impact Statement. 2 tabs., 3 figs.

  7. Environmental impact assessment for uranium mine, mill and in situ leach projects

    International Nuclear Information System (INIS)

    1997-11-01

    Environmental impact assessments and/or statements are an inherent part of any uranium mining project and are a prerequisite for the future opening of an exploitation and its final closure and decommissioning. Since they contain all information related to the physical, biological, chemical and economic condition of the areas where industrial projects are proposed or planned, they present invaluable guidance for the planning and implementation of environmental mitigation as well as environmental restoration after the mine is closed. They further yield relevant data on the socio-economic impacts of a project. The present report provides guidance on the environmental impact assessment of uranium mining and milling projects, including in situ leach projects which will be useful for companies in the process of planning uranium developments as well as for the regional or national authorities who will assess such developments. Additional information and advice is given through environmental case histories from five different countries. Those case histories are not meant to be prescriptions for conducting assessments nor even firm recommendations, but should serve as examples for the type and extent of work involved in assessments. A model assessment and licensing process is recommended based on the experience of the five countries

  8. Some factors affecting agitation leach test during in-situ leaching of uranium

    International Nuclear Information System (INIS)

    Liao Wensheng; Jiang Yan; Wang Limin; Shi Zhenfeng; Zhao Qiaofu; MARMAR

    2014-01-01

    The agitation leaching test is one of the most fundamental research works in in-situ leaching of uranium. Some factors affecting the test results were analyzed including stirring, leaching time, oxidizer used in alkaline leach, washing solution, the amount and size of ore samples. The results indicate that stirring can enhance diffusion velocity. The leach time l or 2 days is suitable for the samples containing accessible uranium and low acid consumption minerals; whereas 3 or 4 days for those containing refractory ore to leach and slowly acid consuming minerals. For the oxidizer used in alkaline leach, potassium permanganate is better than hydrogen peroxide. Recovery calculated by the leach solution can be directly obtained by its uranium level and the original volume of lixiviant without analyzing and calculating the washing solution. The appropriate amount and size of ore samples for the agitation leaching test are 60 g and <1 mm. By controlling the above factors, the agitation leach test can improve the applicability of the different ore samples and give the more reliable data. (authors)

  9. Environmental impact assessment for uranium mine, mill and in situ leach projects

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-11-01

    Environmental impact assessments and/or statements are an inherent part of any uranium mining project and are a prerequisite for the future opening of an exploitation and its final closure and decommissioning. Since they contain all information related to the physical, biological, chemical and economic condition of the areas where industrial projects are proposed or planned, they present invaluable guidance for the planning and implementation of environmental mitigation as well as environmental restoration after the mine is closed. They further yield relevant data on the socio-economic impacts of a project. The present report provides guidance on the environmental impact assessment of uranium mining and milling projects, including in situ leach projects which will be useful for companies in the process of planning uranium developments as well as for the regional or national authorities who will assess such developments. Additional information and advice is given through environmental case histories from five different countries. Those case histories are not meant to be prescriptions for conducting assessments nor even firm recommendations, but should serve as examples for the type and extent of work involved in assessments. A model assessment and licensing process is recommended based on the experience of the five countries. 1 fig., 5 tabs.

  10. An analysis of prominent prospect of in-situ sandstone type uranium deposits in Yanji basins group, Jilin province

    International Nuclear Information System (INIS)

    Peng Zhidong; Zhang Shuyi

    2003-01-01

    In Mesozoic-Cenozoic era, many medium-small-sized sedimentary basins had been formed in Yanbian draped-faulted region of Jilin Province. The basement of these basins is constituted of U-riched granite body produced during late Hercynian-early Yanshan period. Uranium-mineralization has been found in coal-bearing formation, oil-bearing formation and in tint layer of red formation. On the bases of analyzing of uranium source, geologic tectonic, paleoclimatology, paleogeography, hydrogeology and reconstruction, it is concluded that there is a prominent prospect to discover large in-situ sandstone-type uranium deposits in Yanji basins. (authors)

  11. Field Evaluation of the Restorative Capacity of the Aquifer Downgradient of a Uranium In-Situ Recovery Mining Site

    Energy Technology Data Exchange (ETDEWEB)

    Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-05-22

    A two-part field study was conducted in Smith Ranch-Highland in-situ recovery (ISR) near Douglas, Wyoming, to evaluate the restorative capacity of the aquifer downgradient (i.e., hydrologically downstream) of a Uranium ISR mining site with respect to the transport of uranium and other potential contaminants in groundwater after mining has ceased. The study was partially conducted by checking the Uranium content and the alkalinity of separate wells, some wells had been restored and others had not. A map and in-depth procedures of the study are included.

  12. Monitoring an in-situ uranium mining site with radio tomography

    International Nuclear Information System (INIS)

    Stolarczyk, L.; Mondt, W.; Mays, W.

    1991-01-01

    A field test site has been developed to monitor ground water restoration in an in-situ uranium mining project. Uranium deposited in a shallow buried fluvial sandstone channel (aquifer) has been mined by the injection and recovery of ammonia carbonate leachant from a constellation of drillholes. Ground water restoration is accomplished by injecting clean water into a well and recovering contaminated water from companion wells. The restoration process exchanges clean water for contaminated water in the aquifer. The stratigraphic cross section of the aquifer and the hydro-dynamics of the ground water restoration process is currently being investigated with radio wave tomography. Crosshole continuous wave (CW) radio signals are propagated from a well to a second well in the constellation of drillholes. The magnitude and phase of the radio wave are measured in the second well with Radio Imaging Method (RIM) instruments. The acquired data is processed in tomography algorithms to determine the EM wave propagation constants (attenuation rate [α] and phase constant [β]) in each pixel that covers the image plane between wells. The in-situ electrical conductivity values are computed from the pixel propagation constants. Contaminated ground water causes the conductivity of the local zone of the aquifer to increase. This paper describes the initial radio tomography mapping of the deposit lithology and compares radio tomography and E log conductivity values

  13. In Situ Bioreduction of Uranium (VI) to Submicromolar Levels and Reoxidation by Dissolved Oxygen

    International Nuclear Information System (INIS)

    Wu, Weimin; Carley, Jack M.; Luo, Jian; Ginder-Vogel, Matthew A.; Cardenas, Erick; Leigh, Mary Beth; Hwang, Chaichi; Kelly, Shelly D.; Ruan, Chuanmin; Wu, Liyou; Van Nostrand, Joy; Gentry, Terry J.; Lowe, Kenneth Alan; Mehlhorn, Tonia L.; Carroll, Sue L.; Luo, Wensui; Fields, Matthew Wayne; Gu, Baohua; Watson, David B.; Kemner, Kenneth M.; Marsh, Terence; Tiedje, James; Zhou, Jizhong; Fendorf, Scott; Kitanidis, Peter K.; Jardine, Philip M.; Criddle, Craig

    2007-01-01

    Groundwater within Area 3 of the U.S. Department of Energy (DOE) Environmental Remediation Sciences Program (ERSP) Field Research Center at Oak Ridge, TN (ORFRC) contains up to 135 (micro)M uranium as U(VI). Through a series of experiments at a pilot scale test facility, we explored the lower limits of groundwater U(VI) that can be achieved by in-situ biostimulation and the effects of dissolved oxygen on immobilized uranium. Weekly 2 day additions of ethanol over a 2-year period stimulated growth of denitrifying, Fe(III)-reducing, and sulfate-reducing bacteria, and immobilization of uranium as U(IV), with dissolved uranium concentrations decreasing to low levels. Following sulfite addition to remove dissolved oxygen, aqueous U(VI) concentrations fell below the U.S. Environmental Protection Agency maximum contaminant limit (MCL) for drinking water ( -1 or 0.126 (micro)M). Under anaerobic conditions, these low concentrations were stable, even in the absence of added ethanol. However, when sulfite additions stopped, and dissolved oxygen (4.0-5.5 mg L -1 ) entered the injection well, spatially variable changes in aqueous U(VI) occurred over a 60 day period, with concentrations increasing rapidly from <0.13 to 2.0 (micro)M at a multilevel sampling (MLS) well located close to the injection well, but changing little at an MLS well located further away. Resumption of ethanol addition restored reduction of Fe(III), sulfate, and U(VI) within 36 h. After 2 years of ethanol addition, X-ray absorption near-edge structure spectroscopy (XANES) analyses indicated that U(IV) comprised 60-80% of the total uranium in sediment samples. At the completion of the project (day 1260), U concentrations in MLS wells were less than 0.1 (micro)M. The microbial community at MLS wells with low U(VI) contained bacteria that are known to reduce uranium, including Desulfovibrio spp. and Geobacter spp., in both sediment and groundwater. The dominant Fe(III)-reducing species were Geothrix spp

  14. A novel natural analog in situ stabilization agent

    International Nuclear Information System (INIS)

    Shaw, P.

    1995-01-01

    This report summarizes the laboratory-scale test results on a synthetic analog of natural hematite cement for potential as an in situ treatment and stabilization agent for buried hazardous and radioactive waste. The concept is based on the principle that the ideal waste isolation materials are synthetic analogs of those natural encapsulating materials (cements), which are in equilibrium with the environment in which they occur. If equilibrium is achieved, then such materials will remain intact as long as the natural environment remains unchanged. The specific waste application is long-term stabilization of transuranic-contaminated waste pits and trenches at the Idaho National Engineering Laboratory (INEL). Six properties of the natural analog agent and resulting wasteforms are discussed to access the agent's effectiveness and implementability: hydraulic conductivity; compressive strength; mineralogy and microstructure; compatibility with possible waste materials, nitrates, machine cutting oil, and metallic iron; leachability of hazardous metals; and field application parameters. Data indicated that the iron waste encapsulation materials tested are appropriate choices for buried waste mixed with INEL soil. Iron oxide/gypsum INEL soil wasteforms have hydraulic conductivity values close to the regulatory limit. Wasteforms with soil and wastes have compressive strength greater than the regulatory minimum. Gypsum/iron oxide removes hazardous metals from solution by adsorption and would pass Toxicity Characteristic Leaching Procedure limits for most toxic metals. It appears to be chemically and physically inert with respect to the bulk of the waste materials likely to be found at INEL, and has properties conducive to jet grouting

  15. Laboratory-performance criteria for in situ waste-stabilization materials

    International Nuclear Information System (INIS)

    Shaw, P.; Weidner, J.

    1996-01-01

    The Department of Energy (DOE) Landfill Stabilization Focus Area is investigating a variety of in situ placement methods, grout materials, and characterization techniques for the stabilization of buried low-level transuranic-contaminated waste at Department of Energy sites. In situ stabilization involves underground injection or placement of substances to isolate, treat, or contain buried contaminants. Performance criteria were developed to evaluate various candidate stabilization materials for both long-term stabilization and interim stabilization or retrieval. The criteria are go/no-go, ready, and preliminary. The criterion go/no-go eliminates technologies that are not applicable for in situ treatment of buried waste. The criterion ready indicates that the technology is sufficiently developed and proven to be field demonstrated full-scale. The criterion preliminary indicates the prospective technologies to be potentially applicable to in situ buried waste stabilization, but further development is needed before the technology is ready for field-scale demonstration

  16. Uranium

    International Nuclear Information System (INIS)

    Cuney, M.; Pagel, M.; Leroy, J.

    1992-01-01

    First, this book presents the physico-chemical properties of Uranium and the consequences which can be deduced from the study of numerous geological process. The authors describe natural distribution of Uranium at different scales and on different supports, and main Uranium minerals. A great place in the book is assigned to description and classification of uranium deposits. The book gives also notions on prospection and exploitation of uranium deposits. Historical aspects of Uranium economical development (Uranium resources, production, supply and demand, operating costs) are given in the last chapter. 7 refs., 17 figs

  17. Geochemical data from groundwater at the proposed Dewey Burdock uranium in-situ recovery mine, Edgemont, South Dakota

    Science.gov (United States)

    Johnson, Raymond H.

    2012-01-01

    This report releases groundwater geochemistry data from samples that were collected in June 2011 at the Dewey Burdock proposed uranium in-situ recovery site near Edgemont, South Dakota. The sampling and analytical methods are summarized, and all of the data, including quality assurance/quality control information are provided in data tables.

  18. Multi-coupling dynamic model and 3d simulation program for in-situ leaching of uranium mining

    International Nuclear Information System (INIS)

    Tan Kaixuan; Zeng Sheng; Sang Xiao; Sun Bing

    2010-01-01

    The in-situ leaching of uranium mining is a very complicated non-linear dynamic system, which involves couplings and positive/negative feedback among many factors and processes. A comprehensive, coupled multi-factors and processes dynamic model and simulation method was established to study the in-situ leaching of uranium mining. The model accounts for most coupling among various processes as following: (1) rock texture mechanics and its evolution, (2)the incremental stress rheology of rock deformation, (3) 3-D viscoelastic/ plastic multi-deformation processes, (4) hydrofracturing, (5) tensorial (anisotropic) fracture and rock permeability, (6) water-rock interactions and mass-transport (both advective and diffusive), (7) dissolution-induced chemical compaction, (8) multi-phase fluid flow. A 3-D simulation program was compiled based on Fortran and C++. An example illustrating the application of this model to simulating acidification, production and terminal stage of in situ leaching of uranium mining is presented for the some mine in Xinjiang, China. This model and program can be used for theoretical study, mine design, production management, the study of contaminant transport and restoration in groundwater of in-situ leaching of uranium mining. (authors)

  19. Relationship between characteristics of fan-delta sandstone bodies and in-situ leachable sandstone-type uranium mineralization

    International Nuclear Information System (INIS)

    Nie Fengjun; Zhou Weixun; Guan Taiyang; Li Sitian

    2000-01-01

    Like normal deltas, fan-deltas are composed of three parts, i.e., fan-delta plain, fan-delta front and pre-fin-delta, In-situ leachable uranium deposits are commonly distributed along the margins of in-land basins. The author analyzes the possible relationship between the basic characteristics of fan-delta sandstone bodies and uranium mineralization. Two examples, e.g., the fan delta depositional systems in the eastern part of Jungger basin and the southern part of Yili basin, are given to illustrate the fan-delta vertical sequence and planar distribution of sedimentary facies. It has been pointed out that the braided channel sandstone bodies on delta plain, sub-aqueous distributional channel sandstone bodies and delta front sandstone bodies may be the favourable host rocks for in-situ leachable sandstone uranium deposits

  20. On the stability of sub-stoichiometric uranium oxides

    Science.gov (United States)

    Winer, K.; Colmenares, C. A.; Smith, R. L.; Wooten, F.

    1986-12-01

    The oxidation of clean, high-purity polycrystalline uranium metal surfaces for low exposures to dry oxygen was studied with AES and XPS in an attempt to substantiate claims for the formation of a stable UO surface phase at ambient temperatures. We found no evidence for such a surface phase and found instead that grossly sub-stoichiometric surface oxides were formed after sequential oxygen saturation and heating.

  1. In-situ thermoelectric stabilization of radioactive wastes

    International Nuclear Information System (INIS)

    Brouns, R.A.; Timmerman, C.L.

    1982-02-01

    A new process for stabilizing buried radioactive wastes without exhumation is being developed by Pacific Northwest Laboratory (PNL). The process, known as in situ vitrification, converts waste and contaminated soil to a durable glass and crystalline material by passing an electric current between electrodes placed in the ground. Joule heating created by the flowing current has generated temperatures over 1700 0 C which cause the soil to melt and dissolve or encapsulate the wastes. Engineering-scale tests conducted in the laboratory have melted approximately 45 kgs (30 liters) of soil at a time by this technique. Encouraging results from these engineering-scale tests led to the design and construction of a pilot-scale field test unit which has solidified approximately 9000 kg of simulated contaminated soil per test. Test results and evaluations to date have been very promising. No detectable migration of hazardous species into uncontaminated soil has been found, and volatilization during melting has been very low. Leach studies have found the vitrified soil to be a highly durable waste form similar to pyrex glass. Electrical power costs to solidify a disposal site have been calculated at less than $70 per cubic meter ($2/ft 3 ) of waste. Future activities include both radioactive and nonradioactive pilot and large-scale tests

  2. 36Cl production in situ, and groundwater transport in a uranium ore deposit

    International Nuclear Information System (INIS)

    Cornett, R.J.; Andrews, H.R.; Brown, R.M.; Chant, L.A.; Cramer, J.; Davies, W.G.; Greiner, B.F.; Imahori, Y.; Koslowsky, V.T.; McKay, J.W.; Milton, G.M.; Milton, J.D.C.

    1992-01-01

    The authors have used AMS to measure 36 Cl concentrations produced in situ in ore and in groundwater within the 1.3 billion year old Cigar Lake uranium ore deposit. 36 Cl concentrations are up to 300 times higher in the ore zone than in the surrounding aquifer. Based on 36 Cl ingrowth, the authors calculate the residence time of water within the ore zone to be 100,000 to 300,000 years. Since the geologic setting of this deposit is a very close natural analogue to a proposed nuclear fuel waste repository, this analysis demonstrates that natural geological barriers can effectively isolate mobile radionuclides from an open, regional groundwater flow system over millennia

  3. In-situ neutron diffraction characterization of temperature dependence deformation in α-uranium

    Science.gov (United States)

    Calhoun, C. A.; Garlea, E.; Sisneros, T. A.; Agnew, S. R.

    2018-04-01

    In-situ strain neutron diffraction measurements were conducted at temperature on specimens coming from a clock-rolled α-uranium plate, and Elasto-Plastic Self-Consistent (EPSC) modeling was employed to interpret the findings. The modeling revealed that the active slip systems exhibit a thermally activated response, while deformation twinning remains athermal over the temperature ranges explored (25-150 °C). The modeling also allowed assessment of the effects of thermal residual stresses on the mechanical response during compression. These results are consistent with those from a prior study of room-temperature deformation, indicating that the thermal residual stresses strongly influence the internal strain evolution of grain families, as monitored with neutron diffraction, even though accounting for these residual stresses has little effect on the macroscopic flow curve, except in the elasto-plastic transition.

  4. Bio-chemical remediation of under-ground water contaminated by uranium in-situ leaching

    International Nuclear Information System (INIS)

    Wang Qingliang; Li Qian; Zhang Hongcan; Hu Eming; Chen Yongbo

    2014-01-01

    In the process of uranium in-situ leaching, it was serious that strong acid, uranium and heavy metals, and SO_4"2"-, NO_3"- could contaminate underground water. To remedy these pollutants, conventional methods are high-cost and low-efficient, so a bio-chemical remediation method was proposed to cope with the under-ground water pollution in this study. The results showed, in the chemical treatment with Ca(OH)_2 neutralization, pH went up from 2.0 to 7.0, the removal rates of U, Mn"2"+, Zn"2"+, Pb"2"+, SO_4"2"-, NO_3"- were 91.5%, 78.3%, 85.1%, 100%, 71.4% and 2.6% respectively, SO_4"2"- and NO_3"- need to be treated again by bio-method. In the biological process, the Hydraulic Retention Time (HRT) of bioreactor was controlled at 42 h, and 100% NO_3"- and 70% SO_4"2"- in the contaminated water were removed; Acidithiobacillus ferrooxidans (A. f) liquid to H_2S showed better absorption effect, can fully meet the process requirements of H_2S removal. (authors)

  5. Enrichment of specific protozoan populations during in situ bioremediation of uranium-contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, Dawn; Giloteaux, L.; Williams, Kenneth H.; Wrighton, Kelly C.; Wilkins, Michael J.; Thompson, Courtney A.; Roper, Thomas J.; Long, Philip E.; Lovley, Derek

    2013-07-28

    The importance of bacteria in the anaerobic bioremediation of groundwater polluted with organic and/or metal contaminants is well-recognized and in some instances so well understood that modeling of the in situ metabolic activity of the relevant subsurface microorganisms in response to changes in subsurface geochemistry is feasible. However, a potentially significant factor influencing bacterial growth and activity in the subsurface that has not been adequately addressed is protozoan predation of the microorganisms responsible for bioremediation. In field experiments at a uranium-contaminated aquifer located in Rifle, CO, acetate amendments initially promoted the growth of metal-reducing Geobacter species followed by the growth of sulfate-reducers, as previously observed. Analysis of 18S rRNA gene sequences revealed a broad diversity of sequences closely related to known bacteriovorous protozoa in the groundwater prior to the addition of acetate. The bloom of Geobacter species was accompanied by a specific enrichment of sequences most closely related to the amoeboid flagellate, Breviata anathema, which at their peak accounted for over 80% of the sequences recovered. The abundance of Geobacter species declined following the rapid emergence of B. anathema. The subsequent growth of sulfate-reducing Peptococcaceae was accompanied by another specific enrichment of protozoa, but with sequences most similar to diplomonadid flagellates from the family Hexamitidae, which accounted for up to 100% of the sequences recovered during this phase of the bioremediation. These results suggest a prey-predator response with specific protozoa responding to increased availability of preferred prey bacteria. Thus, quantifying the influence of protozoan predation on the growth, activity, and composition of the subsurface bacterial community is essential for predictive modeling of in situ uranium bioremediation strategies.

  6. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    The article briefly discusses the Australian government policy and the attitude of political party factions towards the mining and exporting of the uranium resources in Australia. Australia has a third of the Western World's low-cost uranium resources

  7. Uranium

    International Nuclear Information System (INIS)

    Poty, B.; Cuney, M.; Bruneton, P.; Virlogeux, D.; Capus, G.

    2010-01-01

    With the worldwide revival of nuclear energy comes the question of uranium reserves. For more than 20 years, nuclear energy has been neglected and uranium prospecting has been practically abandoned. Therefore, present day production covers only 70% of needs and stocks are decreasing. Production is to double by 2030 which represents a huge industrial challenge. The FBR-type reactors technology, which allows to consume the whole uranium content of the fuel, is developing in several countries and will ensure the long-term development of nuclear fission. However, the implementation of these reactors (the generation 4) will be progressive during the second half of the 21. century. For this reason an active search for uranium ores will be necessary during the whole 21. century to ensure the fueling of light water reactors which are huge uranium consumers. This dossier covers all the aspects of natural uranium production: mineralogy, geochemistry, types of deposits, world distribution of deposits with a particular attention given to French deposits, the exploitation of which is abandoned today. Finally, exploitation, ore processing and the economical aspects are presented. Contents: 1 - the uranium element and its minerals: from uranium discovery to its industrial utilization, the main uranium minerals (minerals with tetravalent uranium, minerals with hexavalent uranium); 2 - uranium in the Earth's crust and its geochemical properties: distribution (in sedimentary rocks, in magmatic rocks, in metamorphic rocks, in soils and vegetation), geochemistry (uranium solubility and valence in magmas, uranium speciation in aqueous solution, solubility of the main uranium minerals in aqueous solution, uranium mobilization and precipitation); 3 - geology of the main types of uranium deposits: economical criteria for a deposit, structural diversity of deposits, classification, world distribution of deposits, distribution of deposits with time, superficial deposits, uranium

  8. Application of controlled release technology to uranium mill tailings stabilization

    International Nuclear Information System (INIS)

    Burton, F.G.; Cataldo, D.A.; Cline, J.F.; Skiens, W.E.

    1981-01-01

    A trifluralin (herbicide) releasing device was developed with a theoretical effective lifetime in excess of 100 years. When placed in a layer in soil, the PCD system will prevent root penetration through that layer without harming the overlying vegetation. Equilibrium concentrations of trifluralin in soil can be adjusted (along with the theoretical life of the device) to suit specific needs. The present system was designed specifically to protect the asphalt layer or clay/aggregate barriers on uranium mill tailings piles; PCD devices composed of pellets could also be implanted over burial sites for radioactive and/or toxic materials, preventing translocation of those materials to plant shoots, and thence into the biosphere

  9. Uranium

    International Nuclear Information System (INIS)

    Mackay, G.A.

    1978-01-01

    The author discusses the contribution made by various energy sources in the production of electricity. Estimates are made of the future nuclear contribution, the future demand for uranium and future sales of Australian uranium. Nuclear power growth in the United States, Japan and Western Europe is discussed. The present status of the six major Australian uranium deposits (Ranger, Jabiluka, Nabarlek, Koongarra, Yeelerrie and Beverley) is given. Australian legislation relevant to the uranium mining industry is also outlined

  10. Uranium

    International Nuclear Information System (INIS)

    1982-01-01

    The development, prospecting, research, processing and marketing of South Africa's uranium industry and the national policies surrounding this industry form the headlines of this work. The geology of South Africa's uranium occurences and their positions, the processes used in the extraction of South Africa's uranium and the utilisation of uranium for power production as represented by the Koeberg nuclear power station near Cape Town are included in this publication

  11. Long-term stabilization considerations for decommissioned and reclaimed uranium sites

    International Nuclear Information System (INIS)

    Abt, S.R.; Nelson, J.D.; Johnson, T.L.

    1988-01-01

    The long-term stabilization of decommissioned uranium mill sites and of reclaimed uranium mill tailings sites encompass a broad spectrum of design capabilities. This paper presents a few of the quantitative methodologies recently developed or refined to evaluate physical factors (i.e. precipitation, fluvial geomorphology, stable slope, slope stabilization with riprap and riprap selection) that influence long-term stabilization of uranium mill and mill tailings sites. It is acknowledged that the degree of refinement of these methodologies are in their infancy and that extensive research and development are warranted to increase the level of assurance. However, these methodologies provide an initial guideline for evaluating long-term stabilization that has not been previously existed. The purpose of this paper is to present a review of currently available state-of-the-art engineering techniques and methodologies for the evaluation of reclamation plans designed to provide long-term stability against potential failure modes. In some cases, evaluative techniques have been developed for long-term stabilization where methodologies have not previously existed. Each methodology to be presented represents a starting point upon which additional research and/or development may be warranted

  12. Remediation of uranium in-situ leaching area at Straz Pod Ralskem, Czech Republic

    Energy Technology Data Exchange (ETDEWEB)

    Vokal, Vojtech; Muzak, Jiri; Ekert, Vladimir [DIAMO, s. e., TUU, Pod Vinici 84, Straz pod Ralskem, 471 27 (Czech Republic)

    2013-07-01

    A large-scale development in exploration and production of uranium ores in the Czech Republic was done in the 2nd half of the 20. century. Many uranium deposits were discovered in the territory of the Czech Republic. One of the most considerable deposits in the Czech Republic is the site Hamr na Jezere - Straz pod Ralskem where both mining methods - the underground mining and the acidic in-situ leaching - were used. The extensive production of uranium led to widespread environmental impacts and contamination of ground waters. Over the period of 'chemical' leaching of uranium (ca. 32 years), a total of more than 4 million tons of sulphuric acid and other chemicals have been injected into the ground. Most of the products (approx. 99.5 %) of the acids reactions with the rocks are located in the Cenomanian aquifer. The contamination of Cenomanian aquifer covers the area larger then 27 km{sup 2}. The influenced volume of groundwater is more than 380 million m{sup 3}. The total amount of dissolved SO{sub 4}{sup 2-} is about 3.6 million tons. After 1990 a large-scale environmental program was established and the Czech government decided to liquidate the ISL Mine and start the remediation in 1996. The remediation consists of contaminated groundwater pumping, removing of the contaminants and discharging or reinjection of treated water. Nowadays four main remedial technological installations with sufficient capacity for reaching of the target values of remedial parameters in 2037 are used - the 'Station for Acid Solutions Liquidation No. One', the 'Mother liquor reprocessing' station, the 'Neutralization and Decontamination Station NDS 6' and the 'Neutralization and Decontamination Station NDS 10'. It is expected that the amount of withdrawn contaminants will vary from 80 000 to 120 000 tons per year. Total costs of all remediation activities are expected to be in excess of 2 billion EUR. (authors)

  13. Uranium

    International Nuclear Information System (INIS)

    Stewart, E.D.J.

    1974-01-01

    A discussion is given of uranium as an energy source in The Australian economy. Figures and predictions are presented on the world supply-demand position and also figures are given on the added value that can be achieved by the processing of uranium. Conclusions are drawn about Australia's future policy with regard to uranium (R.L.)

  14. Uranium

    International Nuclear Information System (INIS)

    Toens, P.D.

    1981-03-01

    The geological setting of uranium resources in the world can be divided in two basic categories of resources and are defined as reasonably assured resources, estimated additional resources and speculative resources. Tables are given to illustrate these definitions. The increasing world production of uranium despite the cutback in the nuclear industry and the uranium requirements of the future concluded these lecture notes

  15. In-situ leaching of Crownpoint, New Mexico, uranium ore: Part 7 - laboratory study of chemical agents for molybdenum restoration

    International Nuclear Information System (INIS)

    Strom, E.T.; Vogt, T.C.

    1985-01-01

    While in-situ leaching has significant advantages over conventional uranium recovery methods, one possible drawback to its use is the potential release of previously insoluble chemical species into the formation water. Before Mobil began a pilot test of in-situ uranium leaching at Crownpoint, New Mexico, extensive laboratory studies were undertaken to develop chemical methods for treating one possible contaminant, molybdenum (Mo). In-situ production of uranium entails oxidizing uranium from the insoluble +4 oxidation state to the soluble, readily complexed +6 state. However, this process also transforms insoluble Mo +4 compounds such as molybdenite or jordesite, MoS 2 , into the soluble T6 form, molybdate, Mo0 4 2- . New Mexico regulations restrict the amount of Mo permissible in formation waters after leaching to less than one ppm. Conceptually, Mo restoration after leaching can be dealt with in one of two ways. (1) The oxidizing environment can be left unchanged with something added to render the molybdate ion insoluble or (2) the environment can be changed to a reducing one, converting the Mo back to the less soluble +4 oxidation state

  16. Effects of nitrate on the stability of uranium in a bioreduced region of the subsurface

    International Nuclear Information System (INIS)

    Wu, Weimin; Carley, Jack M.; Green, Stefan; Luo, Jian; Kelly, Shelly D.; Van Nostrand, Joy; Lowe, Kenneth Alan; Mehlhorn, Tonia L.; Carroll, Sue L.; Boonchayanant, Benjaporn; Loeffler, Frank E.; Jardine, Philip M.; Criddle, Craig

    2010-01-01

    The effects of nitrate on the stability of reduced, immobilized uranium were evaluated in field experiments at a U.S. Department of Energy site in Oak Ridge, TN. Nitrate (2.0 mM) was injected into a reduced region of the subsurface containing high levels of previously immobilized U(IV). The nitrate was reduced to nitrite, ammonium, and nitrogen gas; sulfide levels decreased; and Fe(II) levels increased then deceased. Uranium remobilization occurred concomitant with nitrite formation, suggesting nitrate-dependent, iron-accelerated oxidation of U(IV). Bromide tracer results indicated changes in subsurface flowpaths likely due to gas formation and/or precipitate. Desorption-adsorption of uranium by the iron-rich sediment impacted uranium mobilization and sequestration. After rereduction of the subsurface through ethanol additions, background groundwater containing high levels of nitrate was allowed to enter the reduced test zone. Aqueous uranium concentrations increased then decreased. Clone library analyses of sediment samples revealed the presence of denitrifying bacteria that can oxidize elemental sulfur, H 2 S, Fe(II), and U(IV) (e.g., Thiobacillus spp.), and a decrease in relative abundance of bacteria that can reduce Fe(III) and sulfate. XANES analyses of sediment samples confirmed changes in uranium oxidation state. Addition of ethanol restored reduced conditions and triggered a short-term increase in Fe(II) and aqueous uranium, likely due to reductive dissolution of Fe(III) oxides and release of sorbed U(VI). After two months of intermittent ethanol addition, sulfide levels increased, and aqueous uranium concentrations gradually decreased to <0.1 μM.

  17. Evaluation of chemical stabilizers and windscreens for wind erosion control of uranium mill tailings

    International Nuclear Information System (INIS)

    Elmore, M.R.; Hartley, J.N.

    1984-08-01

    Potential wind erosion of uranium mill tailings is a concern for the surface disposal of tailings at uranium mills. Wind-blown tailings may subsequently be redeposited on areas outside the impoundment. Pacific Northwest Laboratory (PNL) is investigating techniques for fugitive dust control at uranium mill tailings piles. Laboratory tests, including wind tunnel studies, were conducted to evaluate the relative effectiveness of 43 chemical stabilizers. Seventeen of the more promising stabilizers were applied to test plots on a uranium tailings pile at the American Nuclear Corporation-Gas Hills Project mill site in central Wyoming. The durabilities of these materials under actual site conditions were evaluated over time. In addition, field testing of commercially available windscreens was conducted. Test panels were constructed of eight different materials at the Wyoming test site to compare their durability. A second test site was established near PNL to evaluate the effectiveness of windscreens at reducing wind velocity, and thereby reduce the potential for wind erosion of mill tailings. Results of the laboratory land field tests of the chemical stabilizers and windscreens are presented, along with costs versus effectiveness of these techniques for control of wind erosion at mill tailings piles. 12 references, 4 figures, 6 tables

  18. Advancements in exploration and In-Situ Recovery of sedimentary hosted uranium

    International Nuclear Information System (INIS)

    Märten, H.; Marsland-Smith, A.; Ross, J.; Haschke, M.; Kalka, H.; Schubert, J.

    2014-01-01

    This paper describes recent advancements in exploration technologies for sedimentary-hosted uranium deposits as basis for improved model-based planning and optimization of in-situ recovery (ISR). High-resolution shallow (<500 m depth) seismic in combination with refraction tomography is used for high-fidelity imaging of true-depth stratigraphy of sedimentary formations, tectonic faults and specific structures for the improved understanding of (hydro)geology in general and as potential indicator for uranium mineralization in particular. A new-generation geophysical downhole-wireline tool with pulsed neutron generator has been developed (i) to accurately measure U grade (PFN [prompt fission neutron] method with important intool corrections for systematic influences), (ii) to determine geophysical parameters including porosity, density, macroscopic neutron cross section (clay content) and deduced permeability, and (iii) to log the mineral composition (based on element-specific gamma ray spectroscopy applied to natural gamma rays as well as gamma rays from inelastic neutron scattering, thermal-neutron capture and neutron activation) – all by one tool. This new data - together with conventional geophysical and geochemical information – provides an excellent aid to the assessment of ISR feasibility, the design of wellfields and planning of wellfield operation. A new kinetic leaching model (reactive transport) has been specifically adjusted to acidic leaching conditions considering kinetic rates of the main neutralizing and redox reactions as function of both pH and oxidation potential (balance of e- acceptor species). It is used as an effective tool for predicting wellfield recovery curves, estimating chemicals’ consumption and optimizing leaching chemistry (i.e. dosage of chemicals to injection lixiviant) in dependence on mineralogical conditions (abundance of main reactants). (author)

  19. Simulation of in situ uranium bioremediation with slow-release organic amendment injection

    Science.gov (United States)

    Zhang, F.; Parker, J.; Ye, M.; Tang, G.; Wu, W.; Mehlhorn, T.; Gihring, T. M.; Schadt, C.; Watson, D. B.; Brooks, S. C.

    2010-12-01

    In situ bioremediation of a highly uranium-contaminated gravel aquifer with a slow-release electron donor (emulsified edible oil) has been investigated at the US DOE Oak Ridge Integrated Field Research Challenge (ORIFRC) site in east Tennessee. Groundwater at the study location has pH ~6.7 and contains high concentrations of U (5-6 μM), sulfate (1.0-1.2) mM and Ca (3-4 mM). Diluted emulsified oil (20% solution) was injected into three injection wells within 1.5 hrs. Geochemical analysis of site groundwater demonstrated the sequential reduction of nitrate, Mn, Fe(III) and sulfate. The oil was degraded by indigenous microorganisms with acetate as a major product. Rapid removal of U(VI) from the aqueous phase occurred concurrently with acetate production and sulfate reduction. The field test data were analyzed using a reaction network with a kinetic model for lipid hydrolysis and glycerol fermentation and equilibrium reactions representing microbial reduction of sulfate, nitrate, iron, uranium, manganese and carbon dioxide based on the thermodynamic approach of Istok et al. (2010) using the parallelized HGC5 code. Model-simulated chemical concentrations and relative abundance of functional microbial populations are compared with field measurements. Application of the thermodynamically-based modeling approach instead of the widely used multi-Monod kinetic rate law to formulate bioreduction reactions substantially reduces the number of reaction parameters that need to be calibrated thus facilitating a more comprehensive representation of microbial community dynamics. The model developed through this study is expected to aid the design of future bioremediation strategies for the site.

  20. Report on in-situ studies of flash sintering of uranium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Raftery, Alicia Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-24

    Flash sintering is a novel type of field assisted sintering that uses an electric field and current to provide densification of materials on very short time scales. The potential for field assisted sintering techniques to be used in producing nuclear fuel is gaining recognition due to the potential economic benefits and improvements in material properties. The flash sintering behavior has so far been linked to applied and material parameters, but the underlying mechanisms active during flash sintering have yet to be identified. This report summarizes the efforts to investigate flash sintering of uranium dioxide using dilatometer studies at Los Alamos National Laboratory and two separate sets of in-situ studies at Brookhaven National Laboratory’s NSLS-II XPD-1 beamline. The purpose of the dilatometer studies was to understand individual parameter (applied and material) effects on the flash behavior and the purpose of the in-situ studies was to better understand the mechanisms active during flash sintering. As far as applied parameters, it was found that stoichiometry, or oxygen-to-metal ratio, has a significant effect on the flash behavior (time to flash and speed of flash). Composite systems were found to have degraded sintering behavior relative to pure UO2. The critical field studies are complete for UO2.00 and will be analyzed against an existing model for comparison. The in-situ studies showed that the strength of the field and current are directly related to the sample temperature, with temperature-driven phase changes occurring at high values. The existence of an ‘incubation time’ has been questioned, due to a continuous change in lattice parameter values from the moment that the field is applied. Some results from the in-situ experiments, which should provide evidence regarding ion migration, are still being analyzed. Some preliminary conclusions can be made from these results with regard to using field assisted sintering to

  1. In situ bio-remediation of contaminated soil in a uranium deposit

    International Nuclear Information System (INIS)

    Groudev, St.; Spasova, I.; Nicolova, M.; Georgiev, P.

    2005-01-01

    The uranium deposit Curilo, located in Western Bulgaria, for a long period of time was a site of intensive mining activities including both the open-pit and underground techniques as well as in situ leaching of uranium. The mining operations were ended in 1990 but until now both the surface and ground waters and soils within and near the deposit are heavily polluted with radionuclides (mainly uranium and radium) and heavy metals (mainly copper, zinc and cadmium). Laboratory experiments carried out with soil samples from the deposit revealed that an efficient removal of the above-mentioned contaminants was achieved by their solubilizing and washing the soil profile by means of acidified water solutions. The solubilization was connected with the activity of the indigenous soil microflora, mainly with the activity of some acidophilic chemo-litho-trophic bacteria. It was possible to enhance considerably this activity by suitable changes in the levels of some essential environmental factors such as pH and water, oxygen and nutrient contents in the soil. Such treatment was successfully applied also under real field conditions in the deposit. The effluents from the soil profile during the operation above-mentioned contained the pollutants as well as other heavy metals such as iron and manganese dissolved from the soil in concentrations usually higher than the relevant permissible levels for waters intended for use in the agriculture and/or industry. For that reason, these effluents were efficiently cleaned up by means of a natural wetland located near the treated soil. However, such treatment as any other method for treatment of polluted waters is connected with additional costs which increase the total costs for the soil cleanup. A possible way to avoid or at least largely to facilitate the cleanup of the soil effluents is to apply a biotechnological method in which the soil contaminants solubilized in the upper soil layers (mainly in the horizon A) are transferred into

  2. 222Rn levels in Kingsville, Texas, and vicinity near an in situ uranium mine

    International Nuclear Information System (INIS)

    McGehee, T.L.; Martino, M.R.; Harr, T.L.; Samudio, A.

    1994-01-01

    An investigation of the 222 Rn levels in ground water, soils, and indoor air has disclosed two 222 Rn ground-water anomalies in the Kingsville, Texas, area from uranium-enriched sandstones of the Evangeline aquifer. Indoor air 222 Rn levels were measured in summer 1991 (from undetectable to 3.2 pCi/l) and winter 1991-1992 (0.01 to 3.98 pCi/l) to determine seasonal extremes and risk to the public. Soil 222 Rn concentration maps ranging from undetectable to 75.4 pCi/l correlate to the low levels found in homes. Results of this study are based on analyses of 218 water samples, 52 in situ soil samples, and 104 indoor air samples. Water samples were injected into a scintillation mix (EPA/EERF-Manual-78-1) and analyzed by liquid scintillation techniques. Indoor air and soil samples were collected using passive charcoal canisters and analyzed by gamma-ray detection techniques (EPA 520/5-87-005). One ground-water 222 Rn anomaly lies near the permitted boundary of a large uranium deposit that is being mined. Private wells near the ore body yielded, 1,023 to 23,256 pCi/l at the well head. A second anomaly is located 2.5 mi (4 km) north of the uranium ore body near Naval Air Station, Kingsville. Private water wells in this area yielded 442 to 1,950 pCi/l 222 Rn at the well head. The radon anomalies are related to subsurface mineralization, which is one of the known natural geologic hazards of this area. Indoor air 222 Rn levels are well below the U.S. Environmental Protection Agency (US/EPA) action limit of 4 pCi/l. However, the high levels of 222 RN in ground water should be mitigated before entry into the home environment. High 222 Rn levels in ground water were reduced to background levels in household waters by use of a pre-introduction large-capacity holding tank

  3. The development and application of quantitative methods for the determination of in-situ radiometric uranium grade on the Witwatersrand gold and uranium mines

    International Nuclear Information System (INIS)

    Symons, G.

    1985-12-01

    A detailed investigation of background radiation levels near the reef zone in the uranium section of the Western Areas Mine was conducted using a collimated radiometric face scanner. This study demonstrated that these radiation levels can be high; 25% or more of the counts measured when sampling a reef face may originate from a background source, especially from uranium ore rubble on the footwall close to the reef face. A method using a 20mm frontal shield was devised to obtain an accurate background correction. Three calibration schemes, the Area method, the Gamlog method, and the Deconvolution method were implemented for the production of accurate in-situ radiometric uranium grades. This involved the construction of a step-response calibration pad at Pelindaba together with the establisment of appropriate software and underground radiometric sampling procedures. Radiometric grades generated by these calibration procedures from 60 channel sections were on average 10% below those procured from conventional chip sampling. A correlation between gold and uranium grades was also evident. Crushed rock samples were collected to investigate the thorium problem and are still undergoing analysis at the time of writing. Refinements in the design of the collimated face scanner are also described

  4. Reverse osmosis treatment in CO_2 + O_2 to the application of the in-situ leaching of uranium

    International Nuclear Information System (INIS)

    Ruan Zhilong; Li Xilong; Yang Shaowu

    2014-01-01

    Advantages and disadvantages of various groundwater management methods, combined with CO_2 + O_2 characteristics of in situ leaching uranium mining process, use reverse osmosis wastewater treatment technology, has carried on the laboratory test, field condition test and industrial test. Obtained by indoor experiment and field conditions for Cl"- ion concentration variation characteristics; Reverse osmosis treatment effect of wastewater is verified by industrial test, obtained the technical parameters and consumption data, as well as the leaching liquid and adsorption tail liquid pH, SO_4"2"-; Cl"- in the plasma concentration monitoring, and further prove that the reverse osmosis treatment technology is suitable for in-situ leaching of uranium in CO_2 + O_2 in wastewater treatment. (authors)

  5. Laboratory study on leaching of a sandstone-type uranium deposit for acid in-situ leaching

    International Nuclear Information System (INIS)

    Wen Zhenqian; Yao Yixuan; Zheng Jianping; Jiang Yan; Cui Xin; Xing Yongguo; Hao Jinting; Tang Huazhang

    2013-01-01

    Ore samples were took from in-situ leaching experiment boreholes in a sandstone-type uranium deposit. Technological mineralogy study, agitating leaching and column leaching experiments were carried. The results show that the content of minerals consuming acid and deoxidized minerals is low. When sulfuric acid concentration was 1O g/L, initial uranium content was 0.0224%, and liquid-to-solid ratio was l.91, leaching rate of column leaching experiments is 89.19%, acid consumption is 8.2 kg/t ore, acid consumption is 41.88 t/tU. Acid leaching, technology is recommend for field in-situ leaching experiment, sulfuric acid concentration in confecting solution is 10 g/L, and oxidizing agent is needless during leaching process. (authors)

  6. In-situ leaching of crownpoint, NM, uranium ore: Part 7 - Laboratory study of chemical agents for molybdenum restoration

    International Nuclear Information System (INIS)

    Strom, E.T.; Vogt, T.C.

    1987-01-01

    One possible drawback to the use of an in-situ leaching to recover uranium is the potential release of previously insoluble chemical species into the formation water. Before a pilot test of in-situ uranium leaching at Crownpoint, NM, was begun, extensive laboratory studies were undertaken to develop chemical methods for treating one possible contaminant, molybdenum (Mo). New Mexico regulations restrict the amount of Mo permissable in formation waters after leaching to less than 1 ppm. Two techniques to restore Mo after leaching were studied with core and pack tests. These studies suggest that if Mo restoration problems occur in the field, the use of precipitating agents such as Ca/sup 2+/ or reducing agents such as Fe/sup 2+/ may be helpful in ameliorating such problems

  7. Bioassays with caged hyalella azteca to determine in situ toxicity downstream of two Saskatchewan, Canada, uranium operations.

    Science.gov (United States)

    Robertson, Erin L; Liber, Karsten

    2007-11-01

    The main objectives of this in situ study were to evaluate the usefulness of an in situ bioassay to determine if downstream water bodies at the Key Lake and Rabbit Lake uranium operations (Saskatchewan, Canada) were toxic to Hyalella azteca and, if toxicity was observed, to differentiate between the contribution of surface water and sediment contamination to in situ toxicity. These objectives were achieved by performing 4-d in situ bioassays with laboratory-reared H. azteca confined in specially designed, paired, surface water and sediment exposure chambers. Results from the in situ bioassays revealed significant mortality, relative to the respective reference site, at the exposure sites at both Key Lake (p situ mortality of H. azteca at both operations, although this relationship was stronger at Key Lake. At Key Lake, the primary cause of aquatic toxicity to H. azteca did not appear to be correlated with the variables measured in this study, but most likely with a pulse of organic mill-process chemicals released during the time of the in situ study-a transient event that was caused by a problem with the mill's solvent extraction process. The suspected cause of in situ toxicity to H. azteca at Rabbit Lake was high levels of uranium in surface water, sediment, and pore water.

  8. Responses of microbial community functional structures to pilot-scale uranium in situ bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, M.; Wu, W.-M.; Wu, L.; He, Z.; Van Nostrand, J.D.; Deng, Y.; Luo, J.; Carley, J.; Ginder-Vogel, M.; Gentry, T.J.; Gu, B.; Watson, D.; Jardine, P.M.; Marsh, T.L.; Tiedje, J.M.; Hazen, T.C.; Criddle, C.S.; Zhou, J.

    2010-02-15

    A pilot-scale field test system with an inner loop nested within an outer loop was constructed for in situ U(VI) bioremediation at a US Department of Energy site, Oak Ridge, TN. The outer loop was used for hydrological protection of the inner loop where ethanol was injected for biostimulation of microorganisms for U(VI) reduction/immobilization. After 2 years of biostimulation with ethanol, U(VI) levels were reduced to below drinking water standard (<30 {micro}gl{sup -1}) in the inner loop monitoring wells. To elucidate the microbial community structure and functions under in situ uranium bioremediation conditions, we used a comprehensive functional gene array (GeoChip) to examine the microbial functional gene composition of the sediment samples collected from both inner and outer loop wells. Our study results showed that distinct microbial communities were established in the inner loop wells. Also, higher microbial functional gene number, diversity and abundance were observed in the inner loop wells than the outer loop wells. In addition, metal-reducing bacteria, such as Desulfovibrio, Geobacter, Anaeromyxobacter and Shewanella, and other bacteria, for example, Rhodopseudomonas and Pseudomonas, are highly abundant in the inner loop wells. Finally, the richness and abundance of microbial functional genes were highly correlated with the mean travel time of groundwater from the inner loop injection well, pH and sulfate concentration in groundwater. These results suggest that the indigenous microbial communities can be successfully stimulated for U bioremediation in the groundwater ecosystem, and their structure and performance can be manipulated or optimized by adjusting geochemical and hydrological conditions.

  9. Stability of uranium silicides during high energy ion irradiation

    International Nuclear Information System (INIS)

    Birtcher, R.C; Wang, L.M.

    1991-11-01

    Changes induced by 1.5 MeV Kr ion irradiation of both U 3 Si and U 3 Si 2 have been followed by in situ transmission electron microscopy. When irradiated at sufficiently low temperatures, both alloys transform from the crystalline to the amorphous state. When irradiated at temperatures above the temperature limit for ion beam amorphization, both compounds disorder with the Martensite twin structure in U 3 Si disappearing from view in TEM. Prolonged irradiation of the disordered crystalline phases results in nucleation of small crystallites within the initially large crystal grains. The new crystallites increase in number during continued irradiation until a fine grain structure is formed. Electron diffraction yields a powder-like diffraction pattern that indicates a random alignment of the small crystallites. During a second irradiation at lower temperatures, the small crystallizes retard amorphization. After 2 dpa at high temperatures, the amorphization dose is increased by over twenty times compared to that of initially unirradiated material

  10. Ab initio study on structural stability of uranium carbide

    International Nuclear Information System (INIS)

    Sahoo, B.D.; Joshi, K.D.; Gupta, Satish C.

    2013-01-01

    First principles calculations have been performed using plane wave pseudopotential and full potential linearized augmented plane wave (FP-LAPW) methods to analyze structural, elastic and dynamic stability of UC under hydrostatic compression. Our calculations within pseudopotential method suggest that the rocksalt (B1) structure will transform to body centered orthorhombic (bco) structure at ∼21.5 GPa. The FP-LAPW calculations put this transition at 23 GPa. The transition pressures determined from our calculations though agree reasonably with the experimental value of 27 GPa, the high pressure bco structure suggested by theory differs slightly from the experimentally reported pseudo bco phase. The elastic stability analysis of B1 phase suggests that the B1 to bco transition is driven by the failure of C 44 modulus. This finding is further substantiated by the lattice dynamic calculations which demonstrate that the B1 phase becomes dynamically unstable around the transition pressure and the instability is of long wavelength nature

  11. Plasma spheroidization and high temperature stability of lanthanum phosphate and its compatibility with molten uranium

    Energy Technology Data Exchange (ETDEWEB)

    Ananthapadmanabhan, P.V. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)], E-mail: pvananth@barc.gov.in; Sreekumar, K.P.; Thiyagarajan, T.K.; Satpute, R.U. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Krishnan, K.; Kulkarni, N.K. [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kutty, T.R.G. [Radiometallurgy Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2009-01-15

    Lanthanum phosphate has excellent thermal stability and corrosion resistance against many molten metals and other chemically corrosive environments. Lanthanum phosphate (LaPO{sub 4}) was synthesized from lanthanum oxalate by thermal dissociation of the oxalate to the oxide, followed by conversion to hydrated lanthanum phosphate (LaPO{sub 4}.0.5H{sub 2}O). Thermal treatment of LaPO{sub 4}.0.5H{sub 2}O above 773 K resulted in the irreversible transformation of the hydrated phase to the stable monazite phase. Thermal and chemical stability of monazite was studied by plasma spheroidization experiments using a DC thermal plasma reactor set up. Compatibility of monazite with molten uranium was studied by thermal analysis. Results showed that monazite is thermally stable up to its melting point and also is resistant towards attack by molten uranium. Adherent coatings of LaPO{sub 4} could be deposited onto various substrates by atmospheric plasma spray technique.

  12. Plasma spheroidization and high temperature stability of lanthanum phosphate and its compatibility with molten uranium

    International Nuclear Information System (INIS)

    Ananthapadmanabhan, P.V.; Sreekumar, K.P.; Thiyagarajan, T.K.; Satpute, R.U.; Krishnan, K.; Kulkarni, N.K.; Kutty, T.R.G.

    2009-01-01

    Lanthanum phosphate has excellent thermal stability and corrosion resistance against many molten metals and other chemically corrosive environments. Lanthanum phosphate (LaPO 4 ) was synthesized from lanthanum oxalate by thermal dissociation of the oxalate to the oxide, followed by conversion to hydrated lanthanum phosphate (LaPO 4 .0.5H 2 O). Thermal treatment of LaPO 4 .0.5H 2 O above 773 K resulted in the irreversible transformation of the hydrated phase to the stable monazite phase. Thermal and chemical stability of monazite was studied by plasma spheroidization experiments using a DC thermal plasma reactor set up. Compatibility of monazite with molten uranium was studied by thermal analysis. Results showed that monazite is thermally stable up to its melting point and also is resistant towards attack by molten uranium. Adherent coatings of LaPO 4 could be deposited onto various substrates by atmospheric plasma spray technique

  13. Uranium oxidation kinetics monitored by in-situ X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Zalkind, S., E-mail: shimonzl@nrcn.org.il; Rafailov, G.; Halevy, I.; Livneh, T.; Rubin, A.; Maimon, H.; Schweke, D.

    2017-03-15

    The oxidation kinetics of U-0.1 wt%Cr at oxygen pressures of 150 Torr and the temperature range of 90–150 °C was studied by means of in-situ X-ray diffraction (XRD). A “breakaway” in the oxidation kinetics is found at ∼0.25 μm, turning from a parabolic to a linear rate law. At the initial stage of oxidation the growth plane of UO{sub 2}(111) is the prominent one. As the oxide thickens, the growth rate of UO{sub 2}(220) plane increases and both planes grow concurrently. The activation energies obtained for the oxide growth are Q{sub parabolic} = 17.5 kcal/mol and Q{sub linear} = 19 kcal/mol. Enhanced oxidation around uranium carbide (UC) inclusions is clearly observed by scanning electron microscopy (SEM).

  14. In-situ performance evaluation of radon measurement techniques in Uranium mine exhausts of Jaduguda

    International Nuclear Information System (INIS)

    Patnaik, R.L.; Jha, V.N.; Singh, M.K.; Meena, J.S.; Rajesh Kumar; Srivastava, V.S.; Sethy, N.K.; Ravi, P.M.; Tripathi, R.M.

    2014-01-01

    Several techniques are used for the measurement of the activity concentration of radon in the work place and the environment. Devices like Scintillation cell, Alpha guard and Low Level Radon Detection System (LLRDS) are widely used for the estimation of radon. Some of the devices like scintillation cell is normally used in high activity concentration, whereas, device like LLRDS is used in low activity concentration range. All these above devices are used in ambient mode in which air sample is either collected in a cell or in a chamber and the alpha counts are recorded after a definite delay. In some device, air is allowed to be diffused through a filter and alpha activity is estimated using proper detection system. Passive radon dosimeters can effectively be used both in low and high activity concentration range. The cumulative radon exposure can be assessed using passive radon dosimeters. For in situ performance evaluation an area is required where both high and low level activity concentration of radon is anticipated. Uranium mines exhaust area is presumed to be an area where both these conditions can be found by mere variation in the placement of the device. Inter comparison exercise can also be done effectively at this location using various devices of radon estimation

  15. Uranium

    International Nuclear Information System (INIS)

    Whillans, R.T.

    1981-01-01

    Events in the Canadian uranium industry during 1980 are reviewed. Mine and mill expansions and exploration activity are described, as well as changes in governmental policy. Although demand for uranium is weak at the moment, the industry feels optimistic about the future. (LL)

  16. Stabilization of uranium hexafluoride by hydrolysis method for decommissioning of safeguard laboratory facility

    Energy Technology Data Exchange (ETDEWEB)

    Inagawa, Jun; Hotoku, Shinobu; Oda, Tetsuzo; Aoyagi, Noboru; Magara, Masaaki [Japan Atomic Energy Agency, Nuclear Science and Engineering Directorate, Tokai, Ibaraki (Japan)

    2014-03-15

    In safeguard laboratory (SGL) facility of Nuclear Science Research Institute of JAEA , uranium hexafluoride (UF{sub 6}) of enriched uranium of various enrichment was used for research and development of a spectrometric method for the determination of the enrichment of uranium in April 1983 through March 1993. After completion of this R and D, the UF{sub 6} has been stored in SGL facility. It was decided that the UF{sub 6} is carried to out of the facility, because the SGL facility will be decommissioning until March 2015. To transport and store in safety after transportation, it is necessary that the UF{sub 6} should be converted to stable chemical form. Hydrolysis of UF{sub 6} to uranyl fluoride (UO{sub 2}F{sub 2}) and evaporation to solid state were selected for the stabilization method. The equipment for hydrolysis and evaporation was installed in the SGL facility. Stabilization was operated in this equipment, and all of the UF{sub 6} in the SGL facility was converted to UO{sub 2}F{sub 2} solid state in October 2012 through August 2013. In this report, results of examination and operation for stabilization of UF{sub 6} were reported. (author)

  17. Role of oxidizing agent in the chemistry of in-situ uranium leaching

    International Nuclear Information System (INIS)

    Carlson, R.H.; Norris, R.D.; Schellinger, R.

    1982-01-01

    Synthetic two-component mixtures (uraninite and iron sulfide) as well as native uranium ores obtained from Texas and Wyoming have been examined. Physical/chemical ore properties are correlated with observed laboratory leach response. Data show a large inherent selectivity of oxidant for uranium in the early stages of a leach period. Uranium head grade was found to increase in a nearly linear fashion with hydrogen peroxide concentration in the leach solution. As uranium in the ore is depleted, uranium response decreases and the oxidant serves mainly to leach iron sulfide gangue material. 6 refs

  18. In-situ thermeolectric stabilization of radioactive wastes

    International Nuclear Information System (INIS)

    Brouns, R.A.; Timmerman, C.L.

    1982-01-01

    Current analysis indicates that in situ vitrification is applicable to many wastes and soil types at a cost an order of magnitude less than exhumation, processing, and transportation to a deep geological disposal site. Once the waste materials have been solidified, future ground subsidence, wind erosion and plant or animal intrusion are virtually eliminated. Furthermore, the waste form is extremely durable

  19. Latex-modified grouts for in-situ stabilization of buried transuranic/mixed waste

    International Nuclear Information System (INIS)

    Allan, M.L.

    1996-06-01

    The Department of Applied Science at Brookhaven national Laboratory was requested to investigate latex-modified grouts for in-situ stabilization of buried TRU/mixed waste for INEL. The waste exists in shallow trenches that were backfilled with soil. The objective was to formulate latex-modified grouts for use with the jet grouting technique to enable in-situ stabilization of buried waste. The stabilized waste was either to be left in place or retrieved for further processing. Grouting prior to retrieval reduces the potential release of contaminants. Rheological properties of latex-modified grouts were investigated and compared with those of conventional neat cement grouts used for jet grouting

  20. IN-SITU CHEMICAL STABILIZATION OF METALS AND RADIONUCLIDES THROUGH ENHANCED ANAEROBIC REDUCTIVE PRECIPITATION

    Energy Technology Data Exchange (ETDEWEB)

    Christopher C. Lutes; Angela Frizzell, PG; Todd A. Thornton; James M. Harrington

    2003-08-01

    The objective of this NETL sponsored bench-scale study was to demonstrate the efficacy of enhanced anaerobic reductive precipitation (EARP) technology for precipitating uranium using samples from contaminated groundwater at the Fernald Closure Project (FCP) in Cincinnati, Ohio. EARP enhances the natural biological reactions in the groundwater through addition of food grade substrates (typically molasses) to drive the oxidative-reductive potential of the groundwater to a lower, more reduced state, thereby precipitating uranium from solution. In order for this in-situ technology to be successful in the long term, the precipitated uranium must not be re-dissolved at an unacceptable rate once groundwater geochemical conditions return to their pretreatment, aerobic state. The approach for this study is based on the premise that redissolution of precipitated uranium will be slowed by several mechanisms including the presence of iron sulfide precipitates and coatings, and sorption onto fresh iron oxides. A bench-scale study of the technology was performed using columns packed with site soil and subjected to a continuous flow of uranium-contaminated site groundwater (476 {micro}g/L). The ''treated'' column received a steady stream of dilute food grade molasses injected into the contaminated influent. Upon attainment of a consistently reducing environment and demonstrated removal of uranium, an iron sulfate amendment was added along with the molasses in the influent solution. After a month long period of iron addition, the treatments were halted, and uncontaminated, aerobic, unamended water was introduced to the treated column to assess rebound of uranium concentrations. In the first two months of treatment, the uranium concentration in the treated column decreased to the clean-up level (30 {micro}g/L) or below, and remained there for the remainder of the treatment period. A brief period of resolubilization of uranium was observed as the treated column

  1. Discussion on well field technology for acid in-situ leaching of uranium at a deposit of Yining uranium mine

    International Nuclear Information System (INIS)

    Ye Shandong; Wu Yunhui; Yin Guifang

    2005-01-01

    The characteristics of geology and hydrogeology of a uranium deposit, the make-up and use of lixiviant, equilibrium control of push-pull, improvement of air lift efficiency, layout of well net, and management of well construction are described. (authors)

  2. Research on the characterization and conditioning of uranium mill tailings. II. Thermal stabilization of uranium mill tailings: technical and economic evaluation. Volume 2

    International Nuclear Information System (INIS)

    Dreesen, D.R.; Cokal, E.J.; Thode, E.F.; Wangen, L.E.; Williams, J.M.

    1983-06-01

    A method of conditioning uranium mill tailings has been devised to greatly reduce radon emanation and contaminant leachability by using high-temperature treatments, i.e., thermal stabilization. The thermally stabilized products appear resistant to weathering as measured by the effects of grinding and water leaching. The technical feasibility of the process has been partially verified in pilot-scale experiments. A conceptual thermal stabilization process has been designed and the economics of the process show that the thermal stabilization of tailings can be cost competitive compared with relocation of tailings during remedial action. The alteration of morphology, structure, and composition during thermal treatment would indicate that this stabilization method may be a long-lasting solution to uranium mill tailings disposal problems

  3. Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R M

    1976-01-01

    Evidence of expanding markets, improved prices and the short supply of uranium became abundantly clear in 1975, providing the much needed impetus for widespread activity in all phases of uranium operations. Exploration activity that had been at low levels in recent years in Canada was evident in most provinces as well as the Northwest Territories. All producers were in the process of expanding their uranium-producing facilities. Canada's Atomic Energy Control Board (AECB) by year-end had authorized the export of over 73,000 tons of U/sub 3/0/sub 8/ all since September 1974, when the federal government announced its new uranium export guidelines. World production, which had been in the order of 25,000 tons of U/sub 3/0/sub 8/ annually, was expected to reach about 28,000 tons in 1975, principally from increased output in the United States.

  4. Reduction and immobilization of uranium in the subsurface: controls, mechanisms, and implications for in situ bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Stylo, M. A.

    2015-07-01

    Decades of uranium (U) mining, milling and military use left a legacy of U contamination around the world. The radioactivity and chemical toxicity of U at contaminated sites pose an acute and long-term hazard to human health and the surrounding environment. In order to diminish the risk, in situ bioremediation methods, which contribute to contaminant immobilization, are proposed. Nevertheless, the reported prevalent formation of labile and non-crystalline U(IV) species as a result of microbial U(VI) reduction, in contrast to more stable and crystalline uraninite, undermines the effectiveness of the applied bioremediation. Therefore, a holistic understanding of the controls and mechanisms that govern the formation of non-crystalline U(IV) in the environment is at the core of this thesis. Presence of common groundwater solutes (sulfate, silicate and phosphate) were shown to induce the production of bacterial extracellular polymeric substances (biofilm matrix components), which in turn increases the formation of non-crystalline U(IV) as a result of microbial U reduction. In contrast, a field study suggested that non-crystalline U(IV) was a product of abiotic U reduction followed by the sequestration of U(IV) ions by the biofilm matrix. Those contrasting theories, motivated us to look for an indicator capable of differentiating between biotic and abiotic U reduction in the environment. Uranium isotope fractionation proved to be an excellent tool. Based on our results, the isotopic signature of biotic U reduction (accumulation of {sup 238}U in the reduced phase) is easily distinguishable from the abiotic U reduction signature (either no isotopic fractionation or fractionation in the opposite direction). When contrasted with U isotope signatures recorded in the sediments, the findings of this study indicated that biological activity contributed to the formation of many ancient and modern U(IV) deposits. Equipped with a tool capable of assessing the origin of the U

  5. Reduction and immobilization of uranium in the subsurface: controls, mechanisms, and implications for in situ bioremediation

    International Nuclear Information System (INIS)

    Stylo, M. A.

    2015-01-01

    Decades of uranium (U) mining, milling and military use left a legacy of U contamination around the world. The radioactivity and chemical toxicity of U at contaminated sites pose an acute and long-term hazard to human health and the surrounding environment. In order to diminish the risk, in situ bioremediation methods, which contribute to contaminant immobilization, are proposed. Nevertheless, the reported prevalent formation of labile and non-crystalline U(IV) species as a result of microbial U(VI) reduction, in contrast to more stable and crystalline uraninite, undermines the effectiveness of the applied bioremediation. Therefore, a holistic understanding of the controls and mechanisms that govern the formation of non-crystalline U(IV) in the environment is at the core of this thesis. Presence of common groundwater solutes (sulfate, silicate and phosphate) were shown to induce the production of bacterial extracellular polymeric substances (biofilm matrix components), which in turn increases the formation of non-crystalline U(IV) as a result of microbial U reduction. In contrast, a field study suggested that non-crystalline U(IV) was a product of abiotic U reduction followed by the sequestration of U(IV) ions by the biofilm matrix. Those contrasting theories, motivated us to look for an indicator capable of differentiating between biotic and abiotic U reduction in the environment. Uranium isotope fractionation proved to be an excellent tool. Based on our results, the isotopic signature of biotic U reduction (accumulation of 238 U in the reduced phase) is easily distinguishable from the abiotic U reduction signature (either no isotopic fractionation or fractionation in the opposite direction). When contrasted with U isotope signatures recorded in the sediments, the findings of this study indicated that biological activity contributed to the formation of many ancient and modern U(IV) deposits. Equipped with a tool capable of assessing the origin of the U(IV) product

  6. In Situ Study of Thermal Stability of Copper Oxide Nanowires at Anaerobic Environment

    Directory of Open Access Journals (Sweden)

    Lihui Zhang

    2014-01-01

    Full Text Available Many metal oxides with promising electrochemical properties were developed recently. Before those metal oxides realize the use as an anode in lithium ion batteries, their thermal stability at anaerobic environment inside batteries should be clearly understood for safety. In this study, copper oxide nanowires were investigated as an example. Several kinds of in situ experiment methods including in situ optical microscopy, in situ Raman spectrum, and in situ transmission electron microscopy were adopted to fully investigate their thermal stability at anaerobic environment. Copper oxide nanowires begin to transform as copper(I oxide at about 250°C and finish at about 400°C. The phase transformation proceeds with a homogeneous nucleation.

  7. Assessment of trace ground-water contaminants release from south Texas in-situ uranium solution-mining sites

    Energy Technology Data Exchange (ETDEWEB)

    Kidwell, J.R.; Humenick, M.J.

    1981-01-01

    The future of uranium solution mining in south Texas depends heavily on the industry's ability to restore production zone ground water to acceptable standards. This study investigated the extent of trace contaminant solubilization during mining and subsequent restoration attempts, first through a literature search centered on uranium control mechanisms, and then by laboratory experiments simulating the mining process. The literature search indicated the complexity of the situation. The number of possible interactions between indigenous elements and materials pointed on the site specificity of the problem. The column studies evaluated three different production area ores. Uranium, molybdenum, arsenic, vanadium, and selenium were analyzed in column effluents. After simulated mining operations were completed, uranium was found to be the most persistent trace element. However, subsequent ground water flushing of the columns could restore in-situ water to EPA recommended drinking water concentrations. Limited data indicated that ground water flowing through mined areas may solubilize molybdenum present in down gradient areas adjacent to the production zone due to increased oxidation potential of ground water if adequate restoration procedures are not followed.

  8. Materials testing for in situ stabilization treatability study of INEEL mixed wastes soils

    International Nuclear Information System (INIS)

    Heiser, J.; Fuhrmann, M.

    1997-09-01

    This report describes the contaminant-specific materials testing phase of the In Situ Stabilization Comprehensive Environment Response, Compensation, and Liability Act (CERCLA) Treatability Study (TS). The purpose of materials testing is to measure the effectiveness of grouting agents to stabilize Idaho National Engineering and Environmental Laboratory (INEEL) Acid Pit soils and select a grout material for use in the Cold Test Demonstration and Acid Pit Stabilization Treatability Study within the Subsurface Disposal Area (SDA) at the Radioactive Waste Management Complex (RWMC). Test results will assist the selecting a grout material for the follow-on demonstrations described in Test Plan for the Cold Test Demonstration and Acid Pit Stabilization Phases of the In Situ Stabilization Treatability Study at the Radioactive Waste Management Complex

  9. Restoration of groundwater quality after in situ uranium leaching. Open file report (final) October 1977-August 1979

    International Nuclear Information System (INIS)

    Riding, J.R.; Rosswog, F.J.

    1979-08-01

    In situ solution mining of uranium has several environmental advantages over other mining techniques. The leaching of uranium, however, alters the ground water in the aquifer where the leaching occurs. A requirement of the mining technique is the control of objectionable materials that are introduced into the water. This report reviews the state of the art in restoring ground water quality. Current restoration practices discussed include disposal wells and solar evaporation ponds. Sweeping techniques by producing water flow from all wells during restoration and recirculating techniques by recharging water from a surface purification plant are evaluated. Methods for predicting the effectiveness and costs of current methods are presented. Possible alternatives for restoration of the ground water quality are described

  10. Potential Aquifer Vulnerability in Regions Down-Gradient from Uranium In Situ Recovery (ISR) Sites

    Science.gov (United States)

    Sandstone-hosted roll-front uranium ore deposits originate when U(VI) dissolved in groundwater is reduced and precipitated as insoluble U(IV) minerals. Groundwater redox geochemistry, aqueous complexation, and solute migration are instrumental in leaching uranium from source rock...

  11. Uranium

    International Nuclear Information System (INIS)

    Perkin, D.J.

    1982-01-01

    Developments in the Australian uranium industry during 1980 are reviewed. Mine production increased markedly to 1841 t U 3 O 8 because of output from the new concentrator at Nabarlek and 1131 t of U 3 O 8 were exported at a nominal value of $37.19/lb. Several new contracts were signed for the sale of yellowcake from Ranger and Nabarlek Mines. Other developments include the decision by the joint venturers in the Olympic Dam Project to sink an exploration shaft and the release of an environmental impact statement for the Honeymoon deposit. Uranium exploration expenditure increased in 1980 and additions were made to Australia's demonstrated economic uranium resources. A world review is included

  12. Uranium

    International Nuclear Information System (INIS)

    Gabelman, J.W.; Chenoweth, W.L.; Ingerson, E.

    1981-01-01

    The uranium production industry is well into its third recession during the nuclear era (since 1945). Exploration is drastically curtailed, and many staffs are being reduced. Historical market price production trends are discussed. A total of 3.07 million acres of land was acquired for exploration; drastic decrease. Surface drilling footage was reduced sharply; an estimated 250 drill rigs were used by the uranium industry during 1980. Land acquisition costs increased 8%. The domestic reserve changes are detailed by cause: exploration, re-evaluation, or production. Two significant discoveries of deposits were made in Mohave County, Arizona. Uranium production during 1980 was 21,850 short tons U 3 O 8 ; an increase of 17% from 1979. Domestic and foreign exploration highlights were given. Major producing areas for the US are San Juan basin, Wyoming basins, Texas coastal plain, Paradox basin, northeastern Washington, Henry Mountains, Utah, central Colorado, and the McDermitt caldera in Nevada and Oregon. 3 figures, 8 tables

  13. Genome-Based Models to Optimize In Situ Bioremediation of Uranium and Harvesting Electrical Energy from Waste Organic Matter

    Energy Technology Data Exchange (ETDEWEB)

    Lovley, Derek R

    2012-12-28

    The goal of this research was to provide computational tools to predictively model the behavior of two microbial communities of direct relevance to Department of Energy interests: 1) the microbial community responsible for in situ bioremediation of uranium in contaminated subsurface environments; and 2) the microbial community capable of harvesting electricity from waste organic matter and renewable biomass. During this project the concept of microbial electrosynthesis, a novel form of artificial photosynthesis for the direct production of fuels and other organic commodities from carbon dioxide and water was also developed and research was expanded into this area as well.

  14. Study in situ of the natural uranium, 60 Co and 137 Cs bioaccumulation factor in fish (Cyprinus carpio)

    International Nuclear Information System (INIS)

    Todoran, A.; Toma, A.; Dulama, C.; Horhoianu, V.; Hirica, O.; Patriche, N.; Tenciu, M.; Talpes, M.; Cristea, V.

    2006-01-01

    The paper presents the results of the 'in situ' research, aiming to determine the bioaccumulation factor of natural uranium, 60 Co and 137 Cs in fish (Cyprinus carpio) - the find link in aquatic ecosystems. The work performed is a part of a radioecological study achieved in the experimental pool of S.C.N. Pitesti. The objective of the research was to evaluate the release of the radioactive materials in the environment as well as to establish the transfer mechanisms of the radionuclides in the trophic chains from the aquatic ecosystem. (authors)

  15. Study in situ of the natural uranium, 60 Co and 137 Cs bioaccumulation factor in fish (Cyprinus carpio)

    Energy Technology Data Exchange (ETDEWEB)

    Todoran, A.; Toma, A.; Dulama, C.; Horhoianu, V.; Hirica, O. [Institute for Nuclear Research, Pitesti (Romania); Patriche, N.; Tenciu, M.; Talpes, M. [CPPPPIP, Galati (Romania); Cristea, V. [Galati Univ. (Romania)

    2006-07-01

    The paper presents the results of the 'in situ' research, aiming to determine the bioaccumulation factor of natural uranium, {sup 60}Co and {sup 137}Cs in fish (Cyprinus carpio) - the find link in aquatic ecosystems. The work performed is a part of a radioecological study achieved in the experimental pool of S.C.N. Pitesti. The objective of the research was to evaluate the release of the radioactive materials in the environment as well as to establish the transfer mechanisms of the radionuclides in the trophic chains from the aquatic ecosystem. (authors)

  16. Microbial communities associated with uranium in-situ recovery mining process are related to acid mine drainage assemblages.

    Science.gov (United States)

    Coral, Thomas; Descostes, Michaël; De Boissezon, Hélène; Bernier-Latmani, Rizlan; de Alencastro, Luiz Felippe; Rossi, Pierre

    2018-07-01

    A large fraction (47%) of the world's uranium is mined by a technique called "In Situ Recovery" (ISR). This mining technique involves the injection of a leaching fluid (acidic or alkaline) into a uranium-bearing aquifer and the pumping of the resulting solution through cation exchange columns for the recovery of dissolved uranium. The present study reports the in-depth alterations brought to autochthonous microbial communities during acidic ISR activities. Water samples were collected from a uranium roll-front deposit that is part of an ISR mine in operation (Tortkuduk, Kazakhstan). Water samples were obtained at a depth of ca 500 m below ground level from several zones of the Uyuk aquifer following the natural redox zonation inherited from the roll front deposit, including the native mineralized orebody and both upstream and downstream adjacent locations. Samples were collected equally from both the entrance and the exit of the uranium concentration plant. Next-generation sequencing data showed that the redox gradient shaped the community structures, within the anaerobic, reduced, and oligotrophic habitats of the native aquifer zones. Acid injection induced drastic changes in the structures of these communities, with a large decrease in both cell numbers and diversity. Communities present in the acidified (pH values acid mine drainage, with the dominance of Sulfobacillus sp., Leptospirillum sp. and Acidithiobacillus sp., as well as the archaean Ferroplasma sp. Communities located up- and downstream of the mineralized zone under ISR and affected by acidic fluids were blended with additional facultative anaerobic and acidophilic microorganisms. These mixed biomes may be suitable communities for the natural attenuation of ISR mining-affected subsurface through the reduction of metals and sulfate. Assessing the effect of acidification on the microbial community is critical to evaluating the potential for natural attenuation or active bioremediation strategies

  17. Removal of 226Ra from tailings pond effluents and stabilization of uranium mine tailings. Bench and pilot scale studies

    International Nuclear Information System (INIS)

    Schmidtke, N.W.; Averill, D.; Bryant, D.N.; Wilkinson, P.; Schmidt, J.W.

    1978-01-01

    Increased world demand for uranium has resulted in recent expansion of Canadian uranium mining operations. Problems have been identified with the discharge of radionuclides such as 226 Ra from tailings pond effluents and with the stabilization of mine tailings. At Environment Canada's Wastewater Technology Centre (WTC) two projects were undertaken in cooperation with the Canadian Uranium Mining Industry and other federal government agencies to address these problems. The first project reports on the progress of bench and pilot scale process simulations for the development of a data base for the design of a full scale mechanical physical/chemical 226 Ra removal waste treatment system with an effluent target level of 10 pCi 226 Ra total per litre. The second project addresses problems of the leachability of radionuclides and the stabilization of both uranium mine tailings and BaRaSO 4 sediments from the treatment of acid seepages

  18. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Recent decisions by the Australian Government will ensure a significant expansion of the uranium industry. Development at Roxby Downs may proceed and Ranger may fulfil two new contracts but the decision specifies that apart from Roxby Downs, no new mines should be approved. The ACTU maintains an anti-uranium policy but reaction to the decision from the trade union movement has been muted. The Australian Science and Technology Council (ASTEC) has been asked by the Government to conduct an inquiry into a number of issues relating to Australia's role in the nuclear fuel cycle. The inquiry will examine in particular Australia's nuclear safeguards arrangements and the adequacy of existing waste management technology. In two additional decisions the Government has dissociated itself from a study into the feasibility of establishing an enrichment operation and has abolished the Uranium Advisory Council. Although Australian reserves account for 20% of the total in the Western World, Australia accounts for a relatively minor proportion of the world's uranium production

  19. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The French Government has decided to freeze a substantial part of its nuclear power programme. Work has been halted on 18 reactors. This power programme is discussed, as well as the effect it has on the supply of uranium by South Africa

  20. Erosional stability of rehabilitated uranium mine structures incorporating natural landform characteristics, northern tropical Australia

    International Nuclear Information System (INIS)

    East, T.J.; Uren, C.J.; Noller, B.N.; Cull, R.F.; Curley, P.M.; Unger, C.J.

    1994-01-01

    Australian Government guidelines specify that tailings containment structures at rehabilitated uranium mines in the Alligator Rivers Region of tropical northern Australia should have an engineered structural life of 1000 years. As part of the containment structure design process, erosion plots incorporating both regional geomorphological characteristics (concave hillslope profiles and a weathering-resistant rock cover of schist) and more conventional engineering design parameters (straight slopes and mine waste rock) were constructed at the Ranger Uranium Mine. The plots were monitored for storm runoff, and concentrations of solutes, suspended solids and selected ions over successive wet seasons. The concave slopes (the hillslope analogues) had lower peak discharges and lower concentrations of suspended solids than the straight slopes. However, solute concentrations in runoff from the schist covered (hillslope) slopes were higher than from the waste rock covered plots. Solute (mainly magnesium sulfate) concentrations for both rock types decreased by about an order of magnitude over the wet season. High sulfate concentrations are also likely to decrease substantially after several wet seasons, due to settlement of the waste rock and a reduction in rates of weathering. Development of a vegetation cover on the rehabilitated landforms will reduce the high suspended sediment concentrations. These initial results suggest that rehabilitated uranium mine structures which utilise selected features of stable natural landforms in their design may have greater erosional stability than more conventionally engineered structures. (orig.)

  1. In-situ stabilization of radioactive zirconium swarf

    Science.gov (United States)

    Hess, Clay C.

    1999-01-01

    The method for treating ignitable cutting swarf in accordance with the present invention involves collecting cutting swarf in a casting mold underwater and injecting a binder mixture comprising vinyl ester styrene into the vessel to fill void volume; and form a mixture comprising swarf and vinyl ester styrene; and curing the mixture. The method is especially useful for stabilizing the ignitable characteristics of radioactive zirconium cutting swarf, and can be used to solidify zirconium swarf, or other ignitable finely divided material, underwater. The process could also be performed out of water with other particulate wastes.

  2. Stabilization of microorganisms for in situ degradation of toxic chemicals

    International Nuclear Information System (INIS)

    Crawford, R.L.; Ralston, D.R.

    1993-01-01

    Methods for large-scale microencapsulation of bacteria and nutrients into microbeads with small enough diameters to travel through aquifers have been developed at the University of Idaho. Both free and immobilized cells of Flavobacterium ATCC 39723, a gram-negative aerobe that degrades various chlorinated phenols, into aquifer microcosms, through which pentachlorophenol (PCP)-contaminated groundwater flowed at in situ flow rates. Aquifer samples were collected with an auger from three wells at the University of Idaho Ground Water Research Site, and packed into 24 columns. Some sterile columns were also prepared, by irradiation at the Washington State University Radiation Center. In some of the columns the free Flavobacterium cells were mixed with the aquifer material before packing the columns. In others, agarose-microimmobilized Flavobacterium were mixed into the aquifer material. The effluent from each column was collected daily for 170 days and analyzed by UV spectroscopy or HPLC for remaining PCP. There were no statistically significant differences between the degradation rates of free or encapsulated Flavobacterium in sterile or native aquifer material as tested in these experiments. This work has shown at the lab scale that encapsulated PCP-degrading Flavobacterium were able to survive under conditions of starvation, predation, and lack of water

  3. Superfund Innovative Technology Evaluation - Demonstration Bulletin: In-Situ Soil Stabilization

    Science.gov (United States)

    In-situ stabilization technology immobilizes organics and inorganic compounds in wet or dry soils by using reagents (additives) to polymerize with the soils and sludges producing a cement-like mass. Two basic components of this technology are the Geo-Con/DSM Deep Soil Mixing Sy...

  4. Uranium (VI) complexing by macrocyclic or chelating ligands in aqueous solutions stability, formation kinetics, polarographic properties

    International Nuclear Information System (INIS)

    Brighli, M.

    1984-07-01

    Stability of chelates (with EDTA,N,N ethylenediamine diacetic acid EDDA nitrilotriacetic acid NTA and iminodiacetic acid) of UO 2 2+ and UO 4 species of uranium VI is studied in aqueous solution (NaClO 4 3M at 25 deg celcius). Structure in solution are proposed and discussed for mononuclear species. Only complexing kinetics (formation and acid hydrolysis) of UO 4 with EDDA and NTA are studied by spectrophotometry (other reactions are too fast). Besides UO 2 2+ complexes are formed with crown ethers I5C5 and I8C6 in aqueous solution (TEA ClO 4 M/10 at 25 deg celcius. Complexes are probably stabilized by solvation. Results are confirmed by voltametry and reduction mechanisms of UO 2 2+ and its complexes on mercury drop are proposed. 143 refs [fr

  5. Stability of uranium(VI) doped CSH phases in high saline water

    Energy Technology Data Exchange (ETDEWEB)

    Wolter, Jan-Martin; Schmeide, Katja [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes

    2017-06-01

    To evaluate the long-term stability of U(VI) doped calcium silicate hydrate (CSH) phases at high saline conditions, leaching experiments with NaCl, NaCl/Na{sub 2}SO{sub 4} and NaCl/NaHCO{sub 3} containing solutions were performed. Time-resolved laser-induced fluorescence spectroscopy (TRLFS), infrared spectroscopy (IR) and X-ray powder diffraction (XRD) were applied to study the U(VI) binding onto the CSH phases and to get a deeper understanding of structural changes due to leaching. Results indicate that neither NaCl nor Na{sub 2}SO{sub 4} affect the structural stability of CSH phases and their retention potential for U(VI). However, carbonate containing solutions lead to a decomposition of CSH phases and thus, to a release of incorporated uranium.

  6. Aqueous suspensions of carbon nanotubes: surface oxidation, colloidal stability and uranium sorption.

    Science.gov (United States)

    Schierz, A; Zänker, H

    2009-04-01

    The objective of this study is to obtain information on the behaviour of carbon nanotubes (CNTs) as potential carriers of pollutants in the case of accidental CNT release to the environment and on the properties of CNTs as a potential adsorbent material in water purification. The effects of acid treatment of CNTs on (i) the surface properties, (ii) the colloidal stability and (iii) heavy metal sorption are investigated, the latter being exemplified by uranium(VI) sorption. There is a pronounced influence of surface treatment on the behaviour of the CNTs in aqueous suspension. Results showed that acid treatment increases the amount of acidic surface groups on the CNTs. Therefore, acid treatment has an increasing effect on the colloidal stability of the CNTs and on their adsorption capacity for U(VI). Another way to stabilise colloids of pristine CNTs in aqueous suspension is the addition of humic acid.

  7. The stability of uranium microspheres for future application as reference standard in analytical measurements

    Energy Technology Data Exchange (ETDEWEB)

    Middendorp, R.; Duerr, M.; Bosbach, D. [Forschungszentrum Juelich GmbH, IEK-6, 52428 Juelich (Germany)

    2016-07-01

    The monitoring of fuel-cycle facilities provides a tool to confirm the compliant operation, for example with respect to emissions into the environment or to supervise non-proliferation commitments. Hereby, anomalous situations can be detected in a timely manner and responsive action can be initiated to prevent an escalation into an event of severe consequence to society. In order to verify non-nuclear weapon states' compliance with the non-proliferation treaty (NPT), international authorities such as the International Atomic Energy Agency (IAEA) conduct inspections at facilities dealing with fissile or fertile nuclear materials. One measure consists of collection of swipe samples through inspectors for later analysis of collected nuclear material traces in the laboratory. Highly sensitive mass spectrometric methods provide a means to detect traces from nuclear material handling activities that provide indication of undeclared use of the facility. There are, however, no relevant (certified) reference materials available that can be used as calibration or quality control standards. Therefore, an aerosol-generation based process was established at Forschungszentrum Juelich for the production of spherical, mono-disperse uranium oxide micro-particles with accurately characterized isotopic compositions and amounts of uranium in the pico-gram range. The synthesized particles are studied with respect to their suitability as (certified) reference material in ultra-trace analysis. Several options for preparation and stabilization of the particles are available, where preparation of particles in suspension offers the possibility to produces specific particle mixtures. In order to assess the stability of particles, dissolution behavior and isotope exchange effects of particles in liquid suspension is studied on the bulk of suspended particles and also via micro-analytical methods applied for single particle characterization. The insights gained within these studies will

  8. Stabilization and in situ management of radioactive contaminated sediments of Port Hope harbor

    International Nuclear Information System (INIS)

    Dolinar, G.M.; Killey, R.W.D.; Philipase, K.E.

    1991-01-01

    This paper presents the findings of laboratory and field studies undertaken to assess the feasibility of in situ management of contaminated sediments in Port Hope harbor. The contaminated sediments stem from historic releases from an adjacent radium and uranium refinery, and uranium, arsenic, and radium are the most abundant contaminants. With improved emission controls, currently accumulating sediments have much lower levels of contamination, and the harbor waters currently meet water quality limits for the contaminants of concern. Within a few years, however, the continuing sedimentation will render the harbor unusable. Field tests have confirmed the dredging will result in incomplete removal of the contaminated sediments and that sediment suspension and the release of pores waters during dredging will produce harbor water contaminant concentrations that would require the treatment of large volumes of water. In addition, no remedial work can start until a site for the dredged material can be found. The local community inquired whether in situ burial of the sediments and abandonment of the harbor would provide safe disposal

  9. Guidance for disposal of uranium-mill tailings: long-term stabilization of earthen cover materials

    International Nuclear Information System (INIS)

    Voorhees, L.D.; Sale, M.J.; Webb, J.W.; Mulholland, P.J.

    1983-06-01

    The primary hazard associated with uranium-mill tailings is exposure to a radioactive gas, 222 Rn, the concentration of which has been correlated with the occurrence of lung cancer. Previous studies on radon attenuation conclude that the placement of earthen cover materials over the tailings is the most effective technique for reducing radioactive emissions and dispersal of tailings. The success of such a plan, however, depends on long-term protection of these cover materials. 230 Th, which decays to 222 Rn, has a half-life of about 80,000 years. The three major options available for stabilization of uranium-mill tailings are (1) rock cover, (2) soil and revegetation, or (3) a combination of both on different portions of the tailings cover. The optimal choice among these alternatives depends on site-specific characteristics such as climate and local geomorphology and soils, and on design variables such as embankment heights and slopes, modification of upstream drainage, and revegetation practices. Generally, geomorphic evidence suggests that use of soil and vegetation alone will not be adequate to reduce erosion on slopes greater than about 5 0 . For these steeper slopes, riprap will be necessary to maximize the probability of long-term stability. The use of vegetation to control erosion on the flatter portions of the site may be practicable in regions with sufficient rainfall and suitable soil types, but revegetation practices must be carefully evaluated

  10. Uncertainty and variability in laboratory derived sorption parameters of sediments from a uranium in situ recovery site.

    Science.gov (United States)

    Dangelmayr, Martin A; Reimus, Paul W; Johnson, Raymond H; Clay, James T; Stone, James J

    2018-06-01

    This research assesses the ability of a GC SCM to simulate uranium transport under variable geochemical conditions typically encountered at uranium in-situ recovery (ISR) sites. Sediment was taken from a monitoring well at the SRH site at depths 192 and 193 m below ground and characterized by XRD, XRF, TOC, and BET. Duplicate column studies on the different sediment depths, were flushed with synthesized restoration waters at two different alkalinities (160 mg/l CaCO 3 and 360 mg/l CaCO 3 ) to study the effect of alkalinity on uranium mobility. Uranium breakthrough occurred 25% - 30% earlier in columns with 360 mg/l CaCO 3 over columns fed with 160 mg/l CaCO 3 influent water. A parameter estimation program (PEST) was coupled to PHREEQC to derive site densities from experimental data. Significant parameter fittings were produced for all models, demonstrating that the GC SCM approach can model the impact of carbonate on uranium in flow systems. Derived site densities for the two sediment depths were between 141 and 178 μmol-sites/kg-soil, demonstrating similar sorption capacities despite heterogeneity in sediment mineralogy. Model sensitivity to alkalinity and pH was shown to be moderate compared to fitted site densities, when calcite saturation was allowed to equilibrate. Calcite kinetics emerged as a potential source of error when fitting parameters in flow conditions. Fitted results were compared to data from previous batch and column studies completed on sediments from the Smith-Ranch Highland (SRH) site, to assess variability in derived parameters. Parameters from batch experiments were lower by a factor of 1.1 to 3.4 compared to column studies completed on the same sediments. The difference was attributed to errors in solid-solution ratios and the impact of calcite dissolution in batch experiments. Column studies conducted at two different laboratories showed almost an order of magnitude difference in fitted site densities suggesting that experimental

  11. Uncertainty and variability in laboratory derived sorption parameters of sediments from a uranium in situ recovery site

    Science.gov (United States)

    Dangelmayr, Martin A.; Reimus, Paul W.; Johnson, Raymond H.; Clay, James T.; Stone, James J.

    2018-06-01

    This research assesses the ability of a GC SCM to simulate uranium transport under variable geochemical conditions typically encountered at uranium in-situ recovery (ISR) sites. Sediment was taken from a monitoring well at the SRH site at depths 192 and 193 m below ground and characterized by XRD, XRF, TOC, and BET. Duplicate column studies on the different sediment depths, were flushed with synthesized restoration waters at two different alkalinities (160 mg/l CaCO3 and 360 mg/l CaCO3) to study the effect of alkalinity on uranium mobility. Uranium breakthrough occurred 25% - 30% earlier in columns with 360 mg/l CaCO3 over columns fed with 160 mg/l CaCO3 influent water. A parameter estimation program (PEST) was coupled to PHREEQC to derive site densities from experimental data. Significant parameter fittings were produced for all models, demonstrating that the GC SCM approach can model the impact of carbonate on uranium in flow systems. Derived site densities for the two sediment depths were between 141 and 178 μmol-sites/kg-soil, demonstrating similar sorption capacities despite heterogeneity in sediment mineralogy. Model sensitivity to alkalinity and pH was shown to be moderate compared to fitted site densities, when calcite saturation was allowed to equilibrate. Calcite kinetics emerged as a potential source of error when fitting parameters in flow conditions. Fitted results were compared to data from previous batch and column studies completed on sediments from the Smith-Ranch Highland (SRH) site, to assess variability in derived parameters. Parameters from batch experiments were lower by a factor of 1.1 to 3.4 compared to column studies completed on the same sediments. The difference was attributed to errors in solid-solution ratios and the impact of calcite dissolution in batch experiments. Column studies conducted at two different laboratories showed almost an order of magnitude difference in fitted site densities suggesting that experimental methodology

  12. In situ mobility of uranium in the presence of nitrate following sulfate-reducing conditions.

    Science.gov (United States)

    Paradis, Charles J; Jagadamma, Sindhu; Watson, David B; McKay, Larry D; Hazen, Terry C; Park, Melora; Istok, Jonathan D

    2016-04-01

    Reoxidation and mobilization of previously reduced and immobilized uranium by dissolved-phase oxidants poses a significant challenge for remediating uranium-contaminated groundwater. Preferential oxidation of reduced sulfur-bearing species, as opposed to reduced uranium-bearing species, has been demonstrated to limit the mobility of uranium at the laboratory scale yet field-scale investigations are lacking. In this study, the mobility of uranium in the presence of nitrate oxidant was investigated in a shallow groundwater system after establishing conditions conducive to uranium reduction and the formation of reduced sulfur-bearing species. A series of three injections of groundwater (200 L) containing U(VI) (5 μM) and amended with ethanol (40 mM) and sulfate (20 mM) were conducted in ten test wells in order to stimulate microbial-mediated reduction of uranium and the formation of reduced sulfur-bearing species. Simultaneous push-pull tests were then conducted in triplicate well clusters to investigate the mobility of U(VI) under three conditions: 1) high nitrate (120 mM), 2) high nitrate (120 mM) with ethanol (30 mM), and 3) low nitrate (2 mM) with ethanol (30 mM). Dilution-adjusted breakthrough curves of ethanol, nitrate, nitrite, sulfate, and U(VI) suggested that nitrate reduction was predominantly coupled to the oxidation of reduced-sulfur bearing species, as opposed to the reoxidation of U(IV), under all three conditions for the duration of the 36-day tests. The amount of sulfate, but not U(VI), recovered during the push-pull tests was substantially more than injected, relative to bromide tracer, under all three conditions and further suggested that reduced sulfur-bearing species were preferentially oxidized under nitrate-reducing conditions. However, some reoxidation of U(IV) was observed under nitrate-reducing conditions and in the absence of detectable nitrate and/or nitrite. This suggested that reduced sulfur-bearing species may not be fully effective at

  13. In-situ containment and stabilization of buried waste: Annual report FY 1994

    International Nuclear Information System (INIS)

    Allan, M.L.; Kukacka, L.E.

    1994-10-01

    The two landfills of specific interest are the Chemical Waste Landfill (CWL) and the Mixed Waste Landfill (MWL), both located at Sandia National Laboratory. The work is comprised of two subtasks: (1) In-Situ Barriers and (2) In-Situ Stabilization of Contaminated Soils. The main environmental concern at the CWL is a chromium plume resulting from disposal of chromic acid and chromic sulfuric acid into unlined pits. This program has investigated means of in-situ stabilization of chromium contaminated soils and placement of containment barriers around the CWL. The MWL contains a plume of tritiated water. In-situ immobilization of tritiated water with cementitious grouts was not considered to be a method with a high probability of success and was not pursued. This is discussed further in Section 5.0. Containment barriers for the tritium plume were investigated. FY 94 work focused on stabilization of chromium contaminated soil with blast furnace slag modified grouts to bypass the stage of pre-reduction of Cr(6), barriers for tritiated water containment at the MWL, continued study of barriers for the CWL, and jet grouting field trials for CWL barriers at an uncontaminated site at SNL. Cores from the FY 93 permeation grouting field trails were also tested in FY 94

  14. Interaction of uranium with in situ anoxically generated magnetite on steel

    International Nuclear Information System (INIS)

    Rovira, Miquel; El Aamrani, Souad; Duro, Lara; Gimenez, Javier; Pablo, Joan de; Bruno, Jordi

    2007-01-01

    In the high level nuclear waste repository concept, spent nuclear fuel is designed to be encapsulated in steel canisters. Thus, it is necessary to study the influence of the steel and/or its corrosion products on the behaviour of the radionuclides released from the fuel. In this sense, the main objective of this work is to contribute to the knowledge of the influence of the steel and/or its corrosion products on the uranium(VI) retention. To this aim, magnetite (Fe 3 O 4 ) has been generated by anaerobic steel corrosion in an autoclave reactor at an overpressure of 8 atm of H 2 (g). After characterisation by X-ray diffraction (XRD), the obtained corroded steel coupons were contacted, at two different H 2 (g) pressures (1 atm and 7.6 atm), with a U(VI) solution. The evolution of the uranium concentration in solution is determined and a study of the composition of the coupons at the end of the experiments is carried out. The main conclusion obtained from this work is that magnetite generated on a steel coupon is able not only to retain uranium via sorption, but also to reduce hexavalent to tetravalent uranium in a higher extent than commercial magnetite, thus, providing an effective retardation path to the migration of uranium (and, potentially, other actinides) out of the repository

  15. A feasibility study on geological and hydrogeological setting or in-situ leaching mining in a sandstone-type uranium deposit

    International Nuclear Information System (INIS)

    Guo Sanmin.

    1992-01-01

    A comparative study is made of various conditions for in-situ leaching mining in a sandstone-type uranium deposit in Inner Mongolia with those of same types at home and abroad based on a large number of practical information. It is concluded that the deposit basically exhibits the geological conditions for in-situ leaching mining, and tentative plan and suggestion for further work are presented

  16. In situ bioreduction of technetium and uranium in a nitrate-contaminated aquifer

    International Nuclear Information System (INIS)

    IstokD, Jonathan; Senko, J.M.; Krumholz, Lee R.; Watson, David B.; Bogle, Mary Anna; Peacock, Aaron D.; Change, Y.J.; White, David C.

    2004-01-01

    The potential to stimulate an indigenous microbial community to reduce a mixture of U(VI) and Tc(VII) in the presence of high (120 mM) initial NO 3 - co-contamination was evaluated in a shallow unconfined aquifer using a series of single-well, push-pull tests. In the absence of added electron donor, NO 3 - , Tc(VII), and U(VI) reduction was not detectable. However, in the presence of added ethanol, glucose, or acetate to serve as electron donor, rapid NO 3 - utilization was observed. The accumulation of NO 2 - , the absence of detectable NH 4 + accumulation, and the production of N 2 O during in situ acetylene-block experiments suggest that NO 3 - was being consumed via denitrification. Tc(VII) reduction occurred concurrently with NO 3 - reduction, but U(VI) reduction was not observed until two or more donor additions resulted in iron-reducing conditions, as detected by the production of Fe(II). Reoxidation/remobilization of U(IV) was also observed in tests conducted with high (120 mM) but not low (1 mM) initial NO 3 - concentrations and not during acetylene-block experiments conducted with high initial NO 3 - . These results suggest that NO 3 - -dependent microbial U(IV) oxidation may inhibit or reverse U(VI) reduction and decrease the stability of U(IV) in this environment. Changes in viable biomass, community composition, metabolic status, and respiratory state of organisms harvested from down-well microbial samplers deployed during these tests were consistent with the conclusions that electron donor additions resulted in microbial growth, the creation of anaerobic conditions, and an increase in activity of metal-reducing organisms (e.g., Geobacter). The results demonstrate that it is possible to stimulate the simultaneous bioreduction of U(VI) and Tc(VII) mixtures commonly found with NO 3 - co-contamination at radioactive waste sites.

  17. In situ characterization of uranium and americium oxide solid solution formation for CRMP process: first combination of in situ XRD and XANES measurements.

    Science.gov (United States)

    Caisso, Marie; Picart, Sébastien; Belin, Renaud C; Lebreton, Florent; Martin, Philippe M; Dardenne, Kathy; Rothe, Jörg; Neuville, Daniel R; Delahaye, Thibaud; Ayral, André

    2015-04-14

    Transmutation of americium in heterogeneous mode through the use of U1-xAmxO2±δ ceramic pellets, also known as Americium Bearing Blankets (AmBB), has become a major research axis. Nevertheless, in order to consider future large-scale deployment, the processes involved in AmBB fabrication have to minimize fine particle dissemination, due to the presence of americium, which considerably increases the risk of contamination. New synthesis routes avoiding the use of pulverulent precursors are thus currently under development, such as the Calcined Resin Microsphere Pelletization (CRMP) process. It is based on the use of weak-acid resin (WAR) microspheres as precursors, loaded with actinide cations. After two specific calcinations under controlled atmospheres, resin microspheres are converted into oxide microspheres composed of a monophasic U1-xAmxO2±δ phase. Understanding the different mechanisms during thermal conversion, that lead to the release of organic matter and the formation of a solid solution, appear essential. By combining in situ techniques such as XRD and XAS, it has become possible to identify the key temperatures for oxide formation, and the corresponding oxidation states taken by uranium and americium during mineralization. This paper thus presents the first results on the mineralization of (U,Am) loaded resin microspheres into a solid solution, through in situ XAS analysis correlated with HT-XRD.

  18. Engineering solutions to the long-term stabilization and isolation of uranium mill tailings in the United States

    International Nuclear Information System (INIS)

    Sanders, D.R.; Lommler, J.C.

    1995-01-01

    Engineering solutions to the safe and environmentally protective disposal and isolation of uranium mill tailings in the US include many factors. Cover design, materials selection, civil engineering, erosive forces, and cost effectiveness are only a few of those factors described in this paper. The systems approach to the engineering solutions employed in the US is described, with emphasis on the standards prescribed for the Uranium Mill Tailings Remedial Action Project. Stabilization and isolation of the tailings from humans and the environment are the primary goals of the US uranium mill tailings control standards. The performance of cover designs with respect to water infiltration, radon exhalation, geotechnical stability, erosion protection, human and animal intrusion prevention, and longevity are addressed. The need for and frequency of surveillance efforts to ensure continued disposal system performance are also assessed

  19. Testing of a uranium downhole logging system to measure in-situ plutonium concentrations in sediments

    International Nuclear Information System (INIS)

    Kasper, R.B.; Kay, M.A.; Bruns, L.E.; Stokes, J.A.; Steinman, D.K.; Adams, J.

    1980-11-01

    A prototype urainium borehole logging system, developed for uranium exploration, was modified for Pu assay and testing at the site. It uses the delayed fission neutron (DFN) method. It was tested in a retired Pu facility, the 216-Z-1A Crib. General agreement between laboratory determined Pu concentrations in sediment samples and neutron flux measurements was found for the relative distribution with depth

  20. Revegetation/rock cover for stabilization of inactive uranium mill tailings disposal sites

    International Nuclear Information System (INIS)

    Beedlow, P.A.; McShane, M.C.; Cadwell, L.L.

    1982-07-01

    Pacific Northwest Laboratory is developing design and performance guidelines for surface stabilization of inactive uranium mill tailings. In this work, vegetation and rock covers are being evaluated for maintaining long-term integrity of impoundment systems. Methods are being developed to estimate erosion rates associated with rock and/or vegetation covers, and to determine the effects of surface treatments on soil moisture. Interactions between surface treatments and barriers (radon and biological) are being studied as well. The product will be a set of guidelines to aid in designing surface covers. This report presents the status of this program and a discussion of considerations pertinent to the application of surface covers to tailings. Test plots located in Grand Junction, Colorado and Waterflow, New Mexico are being used to study: (1) the interactions between vegetation and radon and biological barriers, (2) the effects of surface covers on soil moisture, and (3) the effects of rock covers on vegetation

  1. Physical stability of asphalt emulsion admix seal radon barrier for uranium mill tailings

    International Nuclear Information System (INIS)

    Gates, T.E.

    1983-09-01

    Pacific Northwest Laboratory, is investigating the use of an asphalt emulsion admix seal to reduce the release of radon from uranium mill tailings. A key requirement of any cover system is its long-term stability; the cover must withstand failure over very long periods of time. An important determinant of overall cover system stability is the integrity of the 6.35-cm (2.5-in.) thick asphalt admix seal. Therefore, the physical stability of this seal was examined. The investigation considered the mechanical interaction between the tailings pile and cover. The potential effect of differential settlement of the tailings pile on the integrity of the seal system was also examined. Results indicate that the minimum span length the seal could withstand without failing is 0.34 m (1.1 ft). This assumes a differential settlement of 4.92 cm (1.94 in.) at the center resulting from the application of a 0.76-m (2.5-ft) cover. At spans greater than 0.60 m (1.97 ft), no tensile strain would develop

  2. Methodologies for evaluating long-term stabilization designs of uranium mill tailings impoundments

    International Nuclear Information System (INIS)

    Nelson, J.D.; Abt, S.R.; Volpe, R.L.; Van Zye, D.; Hinkle, N.E.; Staub, W.P.

    1986-06-01

    Uranium mill tailings impoundments require long-term (200 to 1000 years) stabilization. This report reviews currently available methodologies for evaluating factors that can have a significant influence on tailings stabilization and develops methodologies in technical areas where none presently exist. Mill operators can use these methodologies to assist with (1) the selection of sites for mill tailings impoundments, (2) the design of stable impoundments, and (3) the development of reclamation plans for existing impoundments. These methodologies would also be useful for regulatory agency evaluations of proposals in permit or license applications. Methodologies were reviewed or developed in the following technical areas: (1) prediction of the Probable Maximum Precipitation (PMP) and an accompanying Probable Maximum Flood (PMF); (2) prediction of the stability of local and regional fluvial systems; (3) design of impoundment surfaces resistant to gully erosion; (4) evaluation of the potential for surface sheet erosion; (5) design of riprap for protecting embankments from channel flood flow and overland flow; (6) selection of riprap with appropriate durability for its intended use; and (7) evaluation of oversizing required for marginal quality riprap

  3. Uranium

    International Nuclear Information System (INIS)

    Battey, G.C.; McKay, A.D.

    1988-01-01

    Production for 1986 was 4899 t U 3 O 8 (4154 t U), 30% greater than in 1985, mainly because of a 39% increase in production at Ranger. Exports for 1986 were 4166 t U 3 O 8 at an average f.o.b. unit value of $40.57/lb U 3 O 8 . Private exploration expenditure for uranium in Australia during the 1985-86 fiscal year was $50.2 million. Plans were announced to increase the nominal capacity of the processing plant at Ranger from 3000 t/year U 3 O 8 to 4500 t and later to 6000 t/year. Construction and initial mine development at Olympic Dam began in March. Production is planned for mid 1988 at an annual rate of 2000 t U 3 O 8 , 30 000 t Cu, and 90 000 oz (2800 kg) Au. The first long-term sales agreement was concluded in September 1986. At the Manyingee deposit, testing of the alkaline solution mining method was completed, and the treatment plant was dismantled. Spot market prices (in US$/lb U 3 O 8 ) quoted by Nuexco were generally stable. From January-October the exchange value fluctuated from US$17.00-US$17.25; for November and December it was US$16.75. Australia's Reasonably Assured Resources of uranium recoverable at less than US$80/kg U at December 1986 were estimated as 462 000 t U, 3000 t U less than in 1985. This represents 30% of the total low-cost RAR in the WOCA (World Outside the Centrally Planned Economy Areas) countries. Australia also has 257 000 t U in the low-cost Estimated Additional Resources Category I, 29% of the WOCA countries' total resources in this category

  4. Cost and sensitivity analysis for uranium in situ leach mining. Open file report Oct 79-Mar 81

    International Nuclear Information System (INIS)

    Toth, G.W.; Annett, J.R.

    1981-03-01

    This report presents the results of an assessment of uranium in situ leach mining costs through the application of process engineering and discounted cash flow analysis procedures. A computerized costing technique was developed to facilitate rapid cost analyses. Applications of the cost model will generate mine life capital and operating costs as well as solve for economic production cost per pound U 3 O 8 . Conversely, rate of return may be determined subject to a known selling price. The data bases of the cost model were designed to reflect variations in Texas versus Wyoming site applications. The results of applying the model under numerous ore deposit, operating, well field, and extraction plant conditions for Texas and Wyoming are summarized in the report. Sensitivity analysis of changes in key project parameters have also been tested and are included

  5. Metallogenetic prospecting in 1:2,000,000 scale for in-situ leachable sandstone type uranium deposit

    International Nuclear Information System (INIS)

    Wang Zhengbang; Qin Mingkuan; Zhao Ruiquan; Dong Wenming; Li Tiangang; Zheng Dayu; Li Sen; Lin Shuangxing

    2002-01-01

    By introducing the advanced theory and technology of systematic geo-mapping which is popularized in Central-Asian countries, the project is aimed at metallogenic prospecting in 1:2,000,000 scale for in-situ leachable sandstone type uranium deposits in Xinjiang and its adjacent area. Based on the comprehensive understanding of accumulated data and on the field study in both the work area and the abroad nearby, the authors propose creatively a new concept that the uranium mineralization in the area is controlled by the moderate tectonic movements during the last large-scale orogenic movement, and set up a new epi-genetically metallogenic system of Meso-Cenozoic depositional basins. Furthermore, the temporal-spatial evolution of the ore-controlled Himalaya orogenic movement is brought to light, and a new method to reconstruct the palaeo-tectonic and palaeo-hydrodynamic systems is created. Accordingly, the main differences in metallogenic conditions and prospecting evaluation between the work area and the Central-Asian areas are illustrated, and the favorable and unfavorable influences of the reduction by the exudative oil and gas on the sandstone type uranium mineralization in the work area are explained in detail. Finally, on the basis of compiling the systematic geo-maps and summarizing the assessment criteria, 2 metallogenic provinces and 12 prospecting areas are predicted. This conclusion can provide a scientific foundation for strategic plans to be made by leading groups and other branches. Another achievement of the project is that a guidebook of the systematic geo-mapping theory and technology has been compiled, which is beneficial to the spreading of the method

  6. Persistent U(IV) and U(VI) following in-situ recovery (ISR) mining of a sandstone uranium deposit, Wyoming, USA

    Science.gov (United States)

    Gallegos, Tanya J.; Campbell, Kate M.; Zielinski, Robert A.; Reimus, P.W.; J.T. Clay,; N. Janot,; J. J. Bargar,; Benzel, William M.

    2015-01-01

    Drill-core samples from a sandstone-hosted uranium (U) deposit in Wyoming were characterized to determine the abundance and distribution of uranium following in-situ recovery (ISR) mining with oxygen- and carbon dioxide-enriched water. Concentrations of uranium, collected from ten depth intervals, ranged from 5 to 1920 ppm. A composite sample contained 750 ppm uranium with an average oxidation state of 54% U(VI) and 46% U(IV). Scanning electron microscopy (SEM) indicated rare high uranium (∼1000 ppm U) in spatial association with P/Ca and Si/O attributed to relict uranium minerals, possibly coffinite, uraninite, and autunite, trapped within low permeability layers bypassed during ISR mining. Fission track analysis revealed lower but still elevated concentrations of U in the clay/silica matrix and organic matter (several 10 s ppm) and yet higher concentrations associated with Fe-rich/S-poor sites, likely iron oxides, on altered chlorite or euhedral pyrite surfaces (but not on framboidal pyrite). Organic C (mining, the likely sequestration of uranium within labile iron oxides following mining and sensitivity to changes in redox conditions requires careful attention during groundwater restoration.

  7. Equation of state, phase stability, and phase transformations of uranium-6 wt. % niobium under high pressure and temperature

    Science.gov (United States)

    Zhang, Jianzhong; Vogel, Sven; Brown, Donald; Clausen, Bjorn; Hackenberg, Robert

    2018-05-01

    In-situ time-of-flight neutron diffraction experiments were conducted on the uranium-niobium alloy with 6 wt. % Nb (U-6Nb) at pressures up to 4.7 GPa and temperatures up to 1073 K. Upon static compression at room temperature, the monoclinic structure of U-6Nb (α″ U-6Nb) remains stable up to the highest experimental pressure. Based on the pressure-volume measurements at room temperature, the least-squares fit using the finite-strain equation of state (EOS) yields an isothermal bulk modulus of B0 = 127 ± 2 GPa for the α″-phase of U-6Nb. The calculated zero-pressure bulk sound speed from this EOS is 2.706 ± 0.022 km/s, which is in good agreement with the linear extrapolation of the previous Hugoniot data above 12 GPa for α″ U-6Nb, indicating that the dynamic response under those shock-loading conditions is consistent with the stabilization of the initial monoclinic phase of U-6Nb. Upon heating at ambient and high pressures, the metastable α″ U-6Nb exhibits complex transformation paths leading to the diffusional phase decomposition, which are sensitive to applied pressure, stress state, and temperature-time path. These findings provide new insight into the behavior of atypical systems such as U-Nb and suggest that the different U-Nb phases are separated by rather small energies and hence highly sensitive to compositional, thermal, and mechanical perturbations.

  8. Agar agar-stabilized milled zerovalent iron particles for in situ groundwater remediation

    Energy Technology Data Exchange (ETDEWEB)

    Velimirovic, Milica; Schmid, Doris; Wagner, Stephan; Micić, Vesna; Kammer, Frank von der; Hofmann, Thilo, E-mail: thilo.hofmann@univie.ac.at

    2016-09-01

    Submicron-scale milled zerovalent iron (milled ZVI) particles produced by grinding macroscopic raw materials could provide a cost-effective alternative to nanoscale zerovalent iron (nZVI) particles for in situ degradation of chlorinated aliphatic hydrocarbons in groundwater. However, the aggregation and settling of bare milled ZVI particles from suspension presents a significant obstacle to their in situ application for groundwater remediation. In our investigations we reduced the rapid aggregation and settling rate of bare milled ZVI particles from suspension by stabilization with a “green” agar agar polymer. The transport potential of stabilized milled ZVI particle suspensions in a diverse array of natural heterogeneous porous media was evaluated in a series of well-controlled laboratory column experiments. The impact of agar agar on trichloroethene (TCE) removal by milled ZVI particles was assessed in laboratory-scale batch reactors. The use of agar agar significantly enhanced the transport of milled ZVI particles in all of the investigated porous media. Reactivity tests showed that the agar agar-stabilized milled ZVI particles were reactive towards TCE, but that their reactivity was an order of magnitude less than that of bare, non-stabilized milled ZVI particles. Our results suggest that milled ZVI particles could be used as an alternative to nZVI particles as their potential for emplacement into contaminated zone, their reactivity, and expected longevity are beneficial for in situ groundwater remediation. - Highlights: • Rapid aggregation and sedimentation were observed in bare milled ZVI particles. • Agar agar improved the stability of milled ZVI particle suspensions. • Agar agar enhanced the transport of milled ZVI particles in heterogeneous sands. • Agar agar reduced the reactivity of milled ZVI particles towards TCE.

  9. Agar agar-stabilized milled zerovalent iron particles for in situ groundwater remediation

    International Nuclear Information System (INIS)

    Velimirovic, Milica; Schmid, Doris; Wagner, Stephan; Micić, Vesna; Kammer, Frank von der; Hofmann, Thilo

    2016-01-01

    Submicron-scale milled zerovalent iron (milled ZVI) particles produced by grinding macroscopic raw materials could provide a cost-effective alternative to nanoscale zerovalent iron (nZVI) particles for in situ degradation of chlorinated aliphatic hydrocarbons in groundwater. However, the aggregation and settling of bare milled ZVI particles from suspension presents a significant obstacle to their in situ application for groundwater remediation. In our investigations we reduced the rapid aggregation and settling rate of bare milled ZVI particles from suspension by stabilization with a “green” agar agar polymer. The transport potential of stabilized milled ZVI particle suspensions in a diverse array of natural heterogeneous porous media was evaluated in a series of well-controlled laboratory column experiments. The impact of agar agar on trichloroethene (TCE) removal by milled ZVI particles was assessed in laboratory-scale batch reactors. The use of agar agar significantly enhanced the transport of milled ZVI particles in all of the investigated porous media. Reactivity tests showed that the agar agar-stabilized milled ZVI particles were reactive towards TCE, but that their reactivity was an order of magnitude less than that of bare, non-stabilized milled ZVI particles. Our results suggest that milled ZVI particles could be used as an alternative to nZVI particles as their potential for emplacement into contaminated zone, their reactivity, and expected longevity are beneficial for in situ groundwater remediation. - Highlights: • Rapid aggregation and sedimentation were observed in bare milled ZVI particles. • Agar agar improved the stability of milled ZVI particle suspensions. • Agar agar enhanced the transport of milled ZVI particles in heterogeneous sands. • Agar agar reduced the reactivity of milled ZVI particles towards TCE.

  10. Taoshan uranium ore fields in situ blasting heap leaching rate influence factors to investigate

    International Nuclear Information System (INIS)

    Xie Wangnan; Dong Chunming

    2014-01-01

    Taoshan ore field ore in situ blasting heap leaching out build industrial test and production process, stope leaching rate and leaching cycle is large than that, after analysis, blasting method and cloth liquid way is to affect leaching rate and leaching cycle of the main factors. This paper holds that as far as possible using stratified deep hole blasting of squeezing up ways to reduce the building pile of in-situ leaching ore block rate; Adopting effective cloth tube way, increase the leaching agent and ore contact comprehensive; Introduction of bacterial leaching, and other means to improve leaching rate, shorten production cycle, etc to solve it. (authors)

  11. In situ stabilization of mixed radioactive waste storage tanks and contaminated soil areas

    International Nuclear Information System (INIS)

    Matthern, G.E.; Meservey, R.H.

    1997-01-01

    Within the Department of Energy (DOE) Complex, there are a number of small (<50,000 gallons) underground Storage tanks containing mixed waste materials. The radioactive content of wastes eliminates the feasibility for hazardous waste treatment in accordance with previously prescribed Resource Conservation and Recovery Act (RCRA) technologies. As a result, DOE is funding in situ stabilization technology development for these tanks, Some of this development work has been done at the Idaho National Engineering and Environmental Laboratory (INEEL) and the initial efforts there were concentrated on the stabilization of the contents of the Test Area North (TAN) V-9 Tank. This is a 400 gallon underground tank filled with about 320 gallons of liquids and silty sediments. Sampling data indicates that approximately 50 wt% of the tank contents is aqueous-phase liquids. The vertically oriented cylindrical tank has a conical bottom and a chordal baffle that separates the tank inlet from its outlet. Access to the tank is through a six inch diameter access pipe on top of the tank. Because of the high volume, and the high concentration of aqueous-phase materials, Tank V-9 stabilization efforts have focussed on applying in situ agitation with dry feed addition to stabilize its contents. Materials selected for dry feed addition to this tank include a mixture of Aquaset IIH, and Type I/II Portland cement. This paper describes the results of proof-of-concept tests performed on full scale mockups of the Tank V-9. This proof-of-concept test were used to set operating parameters for in situ mixing, as well as evaluate how variations in Aquaset IIH/Portland cement ratio and sediment to liquid volume affected mixing of the tank

  12. Assessment of the availability of As and Pb in soils after in situ stabilization.

    Science.gov (United States)

    Zhang, Wanying; Yang, Jie; Li, Zhongyuan; Zhou, Dongmei; Dang, Fei

    2017-10-01

    The in situ stabilization has been widely used to remediate metal-contaminated soil. However, the long-term retaining performance of heavy metals and the associated risk after in situ stabilization remains unclear and has evoked amounting concerns. Here, Pb- or As-contaminated soil was stabilized by a commercial amendment. The availability of Pb and As after in situ stabilization were estimated by ten different in vitro chemical extractions and DGT technique. After amendment application, a significant decline in extractable Pb or As was observed in treatments of Milli-Q water, 0.01 M CaCl 2 , 0.1 M NaNO 3 , 0.05 M (NH 4 ) 2 SO 4 , and 0.43 M HOAc. Potential available metal(loid)s determined by DGT also showed remarkable reduction. Meanwhile, the results of in vivo uptake assays demonstrated that Pb concentrations in shoots of ryegrass Lolium perenne L. declined to 12% of the control samples, comparable to the extraction ratio of 0.1 M NaNO 3 (15.8%) and 0.05 M (NH 4 ) 2 SO 4 (17.3%). For As-contaminated soil, 0.43 M HOAC provided a better estimation of relative phytoavailability (64.6 vs. 65.4% in ryegrass) compared to other extraction methods. We propose that 0.1 M NaNO 3 or 0.05 M (NH 4 ) 2 SO 4 for Pb and 0.43 M HOAc for As may serve as surrogate measures to estimate the lability of metal(loid)s after soil remediation of the tested contaminated soils. Further studies over a wider range of soil types and amendments are necessary to validate extraction methods.

  13. Solid-phase data from cores at the proposed Dewey Burdock uranium in-situ recovery mine, near Edgemont, South Dakota

    Science.gov (United States)

    Johnson, Raymond H.; Diehl, Sharon F.; Benzel, William M.

    2013-01-01

    This report releases solid-phase data from cores at the proposed Dewey Burdock uranium in-situ recovery site near Edgemont, South Dakota. These cores were collected by Powertech Uranium Corporation, and material not used for their analyses were given to the U.S. Geological Survey for additional sampling and analyses. These additional analyses included total carbon and sulfur, whole rock acid digestion for major and trace elements, 234U/238U activity ratios, X-ray diffraction, thin sections, scanning electron microscopy analyses, and cathodoluminescence. This report provides the methods and data results from these analyses along with a short summary of observations.

  14. The evaluation of in-situ leaching hydrological-geologic condition in a sandstone-type uranium deposits of a low-grade and thick ledge

    International Nuclear Information System (INIS)

    Jiang Yan

    2014-01-01

    The ore aquifer of a sandstone-type uranium deposits is thick, the grade, and uranium amount per square meter is low. To demonstrate the economic rationality of the in-situ leaching deposit, the Pumping test on the spot, recovery of water levels test, Pumping test and Injection test, Injection test in a Drilling hole, the pumping and injection balance test are carried out. And the hydro geological parameters of mineral aquifer are acquired. The parameters includes coefficient of transmissibility, Coefficient of permeability, Specific discharge of a well and Water injection. Radius of influence etc. The relation between discharge of drilling and Drawdown is researched. The capability of pumping and injection by a drilling hole is determined. The Hydraulic between the aquifer with mineral and the upper and lower aquifer is researched. The reasonable Mining drawdown is testified, the hydrogeological conditions of in-Situ leaching of the mining deposit is found out, this provides necessary parameters and basis for this kind of Situ-leach uranium mining wells, the designing of Spacing of wells, and the economic evaluation of In-situ leaching technology. (author)

  15. Study and application of new chelating resin to recovery uranium from in-situ leach solution with high content saline chloride ion

    International Nuclear Information System (INIS)

    Zhang Jianguo; Qiu Yueshuang; Feng Yu; Deng Huidong; Zhao Chaoya

    2014-01-01

    Research on the adsorption and elution property of D814 chelating resin was carried out aiming at the difficult separation of uranium from high content saline chloride ion in situ leach liquor and the adsorption mechanism is also discussed. Influence factors such as contact time, pH value, Ca"2"+, Mg"2"+ and Cl"- concentration etc. to the resin adsorption were studied. Experimental results show that adsorption rate is lowly which need 6h to arrive at the adsorption equilibrium. The resin adsorption uranium pH in the solution is from l.33 to 9. When total salinity is over 20 g/L, calcium ion, and magnesium ion is about 3 g/L, there are no big influence on resin adsorption capacity. The resin has good chloride ion resistance. When chloride ion is over 60 g/L, it is no influence on resin adsorption uranium. Column experiment results indicate that ratio of saturation volume to break-through point volume is l.82, resin saturation uranium capacity is 40.5 mg. U/_g_(_∓_)_R. When elution volume bed number is 23, the eluted solution uranium concentration is below 80 mg/L. The elution rate of the uranium is 96.2%. (authors)

  16. In-situ stabilization of TRU/mixed waste project at the INEEL

    International Nuclear Information System (INIS)

    Milian, L.W.; Heiser, J.H.; Adams, J.W.; Rutenkroeger, S.P.

    1997-08-01

    Throughout the DOE complex, buried waste poses a threat to the environment by means of contaminant transport. Many of the sites contain buried waste that is untreated, prior to disposal, or insufficiently treated, by today's standards. One option to remedy these disposal problems is to stabilize the waste in situ. This project was in support of the Transuranic/Mixed Buried Waste - Arid Soils product line of the Landfill Focus Area, which is managed currently by the Idaho National Engineering Laboratory (BNL) provided the analytical laboratory and technical support for the various stabilization activities that will be performed as part of the In Situ Stabilization of TRU/Mixed Waste project at the INEL. More specifically, BNL was involved in laboratory testing that included the evaluation of several grouting materials and their compatibility, interaction, and long-term durability/performance, following the encapsulation of various waste materials. The four grouting materials chosen by INEL were: TECT 1, a two component, high density cementious grout, WAXFIX, a two component, molten wax product, Carbray 100, a two component elastomeric epoxy, and phosphate cement, a two component ceramic. A simulated waste stream comprised of sodium nitrate, Canola oil, and INEL soil was used in this study. Seven performance and durability tests were conducted on grout/waste specimens: compressive strength, wet-dry cycling, thermal analysis, base immersion, solvent immersion, hydraulic conductivity, and accelerated leach testing

  17. Comment and response document for the final remedial action plan and site design for stabilization of the inactive uranium mill tailings sites at Slick Rock, Colorado. Revision 2

    International Nuclear Information System (INIS)

    1996-05-01

    This document for the final remedial action plan and site design has been prepared for US Department of Energy Environmental Restoration Division as part of the Uranium Mill Tailings Remedial Action plan. Comments and responses are included for the site design for stabilization of the inactive uranium mill tailings sites at Slick Rock, Colorado

  18. In situ evidence of mineral physical protection and carbon stabilization revealed by nanoscale 3-D tomography

    Science.gov (United States)

    Weng, Yi-Tse; Wang, Chun-Chieh; Chiang, Cheng-Cheng; Tsai, Heng; Song, Yen-Fang; Huang, Shiuh-Tsuen; Liang, Biqing

    2018-05-01

    An approach for nanoscale 3-D tomography of organic carbon (OC) and associated mineral nanoparticles was developed to illustrate their spatial distribution and boundary interplay, using synchrotron-based transmission X-ray microscopy (TXM). The proposed 3-D tomography technique was first applied to in situ observation of a laboratory-made consortium of black carbon (BC) and nanomineral (TiO2, 15 nm), and its performance was evaluated using dual-scan (absorption contrast and phase contrast) modes. This novel tool was then successfully applied to a natural OC-mineral consortium from mountain soil at a spatial resolution of 60 nm, showing the fine structure and boundary of OC, the distribution of abundant nano-sized minerals, and the 3-D organo-mineral association in situ. The stabilization of 3500-year-old natural OC was mainly attributed to the physical protection of nano-sized iron (Fe)-containing minerals (Fe oxyhydroxides including ferrihydrite, goethite, and lepidocrocite), and the strong organo-mineral complexation. In situ evidence revealed an abundance of mineral nanoparticles, in dense thin layers or nano-aggregates/clusters, instead of crystalline clay-sized minerals on or near OC surfaces. The key working minerals for C stabilization were reactive short-range-order (SRO) mineral nanoparticles and poorly crystalline submicron-sized clay minerals. Spectroscopic analyses demonstrated that the studied OC was not merely in crisscross co-localization with reactive SRO minerals; there could be a significant degree of binding between OC and the minerals. The ubiquity and abundance of mineral nanoparticles on the OC surface, and their heterogeneity in the natural environment may have been severely underestimated by traditional research approaches. Our in situ description of organo-mineral interplay at the nanoscale provides direct evidence to substantiate the importance of mineral physical protection for the long-term stabilization of OC. This high-resolution 3-D

  19. Economic and environmental implications of leakage upon in situ uranium mining

    International Nuclear Information System (INIS)

    Popielak, R.S.; Siegel, J.

    1987-01-01

    A computer model was used to simulate the effect of leakage through confining beds on a hypothetical in situ leach operation in an aquifer with a thin mineralized section. The simulations were used to assess economic and potential environmental implications of leakage on an in situ leach operation. Four scenarios were modeled - three representing cases with different degrees of confinement, and the fourth representing a stratified ore zone under a low degree of confinement. The model simulated the travel path and travel time of lixiviant given the hydraulic conditions prescribed in each scenario. The results show that the travel path and travel times vary by about 10% for confinement ranging from nearly impermeable (essentially no leakage) to an extremely low level (thin confinement with a permeability about equal to that of the aquifer) for isotropic aquifer conditions. The aquifer thickness contacted by the lixiviant varied from 85% to 90%

  20. Factors Controlling In Situ Uranium and Technetium Bio-Reduction and Reoxidation at the NABIR Field Research Center

    International Nuclear Information System (INIS)

    Istok, Jonathan; Krumholz, L; McKinley, J.; Gu, B.

    2004-01-01

    Summary of Recent Field Testing: Extensive in situ (in ground) field testing using the push-pull method has demonstrated that indigenous microorganisms in the shallow ( ∼ 20 mM. Field data and laboratory studies suggest that U(IV) is likely oxidized by Fe(III) minerals produced by enzymatic Fe(II) oxidation or by Fe(II) oxidation by nitrite. U(IV) reoxidation rates (10-3 to 10-2 uM/hr) were somewhat larger than U(VI) reduction rates indicating that sustained nitrate removal will be necessary to maintain the stability of U(IV) in this environment

  1. In situ optoacoustic measurement of the pointing stability of femtosecond laser beams

    Science.gov (United States)

    Pushkarev, D.; Mitina, E.; Uryupina, D.; Volkov, R.; Karabytov, A.; Savel'ev, A.

    2018-02-01

    A new method for the in situ acoustic measurement of the beam pointing stability (BPS) of powerful pulsed lasers is tested. A broadband (~6 MHz) piezoelectric transducer placed a few millimeters from the laser spark produces an electric pulse. We show that variation in time of the position of this pulse can be used to assess the BPS down to 1 µrad in a few hundred laser shots. The estimated value coincides well with the BPS estimated using standard measurement in the far field.

  2. Evaluation of the tear film stability after laser in situ keratomileusis using the tear film stability analysis system.

    Science.gov (United States)

    Goto, Tomoko; Zheng, Xiaodong; Klyce, Stephen D; Kataoka, Hisashi; Uno, Toshihiko; Yamaguchi, Masahiko; Karon, Mike; Hirano, Sumie; Okamoto, Shigeki; Ohashi, Yuichi

    2004-01-01

    To evaluate the tear film stability of patients before and after laser in situ keratomileusis (LASIK) using the tear film stability analysis system (TSAS). Prospective observational case series. New videokeratography software for a topographic modeling system (TMS-2N) was developed that can automatically capture consecutive corneal surface images every second for 10 seconds. Thirty-four subjects (64 eyes) who underwent myopia LASIK were enrolled in this study. All subjects were examined with the new system before LASIK and at 1 week, 1 month, 3 months, and 6 months after the surgery. Corneal topographs were analyzed for tear breakup time (TMS breakup time) and breakup area (TMS breakup area). Based on pre-LASIK TSAS analysis, subjects were separated into normal and abnormal TSAS value groups. The criteria for the normal group were either TMS breakup time more than 5 seconds or TMS breakup area less than 0.2. The percentage of the occurrence of superficial punctuate keratitis was compared between the two groups with regard to subject's dry eye signs and symptoms. Tear film stability decreased significantly during the early period after LASIK, as indexed by decreased TMS breakup time and increased TMS breakup area. Tear film instability resolved at 6 months after surgery. Before LASIK, 22 subjects (43 eyes) had normal TSAS evaluation and 12 subjects (21 eyes) were abnormal. After LASIK, among normal TSAS value eyes, 8 of 43 (18.6%) eyes developed superficial punctuate keratitis. In sharp contrast, 14 of 21 (66.7%) eyes in the abnormal group displayed superficial punctuate keratitis, correlating well with the patients' dry eye symptoms. The difference in the presence of superficial punctuate keratitis after LASIK between normal and abnormal TSAS value groups was statistically significant (P <.001). Subjects with abnormal TSAS evaluation also displayed resistance to dry eye treatment and had extended period of recovery. Tear film stability analysis can be a useful

  3. Investigation of disposal of nitrate-bearing effluent from in-situ leaching process by natural evaporation in Yining uranium mine

    International Nuclear Information System (INIS)

    Huang Chongyuan; Li Weicai; Zhang Yutai; Gao Xizhen

    2000-01-01

    Experiments indicated, after lime neutralization and precipitation of nitrate-bearing effluent from in-situ leaching process, uranium concentration increase with the increasing of nitrate concentration. Only when nitrate concentration is <0.5 mg/L, uranium concentration can drop from 1.5-2.0 mg/L to about 1.0 mg/L. The permeability coefficient of soil is about 1.0-1.1 m/d in the place which is scheduled for building natural evaporation pool. After lime neutralization of nitrate-bearing effluent, it can drop to 0.03-0.01 m/d. Setting up water-proof layer in natural evaporation pool can reduce pollution of underground water by uranium, nitrate and ammonium

  4. Comments and responses on the Remedial Action Plan and site design for stabilization of the Inactive Uranium Mill Tailings Site, Grand Junction, Colorado. Revision 1

    International Nuclear Information System (INIS)

    1994-01-01

    This report contains information concerning public comments and responses on the remedial action plan and site design for stabilization of the inactive uranium mill tailings site in Grand Junction, Colorado

  5. A rapid in situ method for determining the ages of uranium oxide minerals: Evolution of the Cigar Lake deposit, Athabasca Basin

    International Nuclear Information System (INIS)

    Fayek, M.; Harrison, T.M.; Grove, M.; Coath, C.D.

    2000-01-01

    The authors present a rapid and accurate technique for making in situ U-Pb isotopic measurements of uranium oxide minerals that utilizes both electron and ion microprobes. U and Pb concentrations are determined using an electron microprobe, whereas the isotopic composition of Pb for the same area is measured using a high-resolution ion microprobe. The advantages of this approach are: mineral separation and chemical digestion are unnecessary; homogeneous uranium oxide standards, which are difficult to obtain, are not required; and precise and accurate U-Pb ages on ∼10 microm spots can be obtained in a matter of hours. The authors have applied their method to study the distribution of U-Pb ages in complexly intergrown uranium oxides from the unconformity-type Cigar Lake uranium deposit, Saskatchewan, Canada. In situ U-Pb results from early formed uraninite define a well-correlated array on concordia with upper and lower intercepts of 1,467 ± 63 Ma and 443 ± 96 Ma (±1σ), respectively. The 1,467 Ma age is interpreted as the minimum age of mineralization and is consistent with the age of clay-mineral alteration (approximately1477 Ma) and magnetization of diagenetic hematite (1,650 to 1,450 Ma) that is associated with these unconformity-type uranium deposits and early diagenesis of the Athabasca Basin sediments. In situ U-Pb isotopic analysis of uraninite and coffinite can document the Pb*/U heterogeneities that can occur on a scale of 15 to 30 microm, thus providing relatively accurate information regarding the timing of fluid interactions associated with the evolution of these deposits

  6. The design and construction of the bottom working for in-situ leaching of fragmented uranium ore by blasting in No. 745 mine

    International Nuclear Information System (INIS)

    Ding Dexin; Yang Shijiao; Li Ming

    1998-11-01

    Bottom working is a very important structure for in-situ leaching of fragmented uranium ore by blasting. Its design and construction should simultaneously satisfy the requirements for receiving fragmented ore, transporting the ore, providing relief space for blast operation, passage for workers and fresh air for the slope and collecting the pregnant solution from spraying over the fragmented ore. The author deals with the design and construction of the complete water cutoff bottom working for collecting the pregnant solution for in-situ leaching of fragmented uranium ore by long hole blast in No. 745 mine in Guangdong Province. The preparation system for the block, the undercutting, the construction process and method of the bottom working and the measures to guide the solution leaked into the surrounding rock mass to the bottom of the block are described in detail

  7. Remote-sensing and geological information for prospective area selection of in-situ leachable sandstone-type uranium deposit in Songliao and Liaohe faulted-depressed basins

    International Nuclear Information System (INIS)

    Yu Baoshan

    1998-01-01

    On the basis of remote-sensing information and geological environments for the formation of in-situ leachable sandstone-type uranium deposits such as geomorphic features, distribution of drainage system, and paleo-alluvial (diluvial) fans and time-space distribution regularities of orehosting rocks and sandstone bodies in Songliao and Liaohe faulted-depressed basins, image features, tectonic patterns and paleo-geographic environment of the prospective areas are discussed for both basins, and based on a great number of petroleum-geological data and comparison analysis, a remote sensing-geological prospecting model for in-situ leachable sandstonetype uranium deposits in the region is established, providing indications for selection of prospective area

  8. The effect of crystal structure stability on the mobility of gas bubbles in intermetallic uranium compounds

    International Nuclear Information System (INIS)

    Rest, J.; Hofman, G.L.; Birtcher, R.C.

    1988-01-01

    Irradiation experiments with certain low-enrichment, high-density, uranium-base intermetallic alloys that are candidate reactor fuel materials, such as U 3 Si and U 6 Fe, have revealed extraordinarily large voids at low and medium fuel burnup. This phenomenon of breakaway swelling does not occur in other fuel types, such as U 3 Si 2 and UAl 3 , where a distribution of relatively small and stable fission gas bubbles forms. In situ transmission electron microscope observations of ion radiation-induced rapid swelling of intermetallic materials are consistent with growth by plastic flow. Large radiation enhancement of plastic flow in amorphous materials has been observed in several independent experiments and is thought to be a general materials phenomenon. The basis for a microscopic theory of fission gas bubble behavior in irradiated amorphous compounds has been formulated. The assumption underlying the overall theory is that the evolution of the porosity from that observed in the crystalline material to that observed in irradiated amorphous U 3 Si as a function of fluence is due to a softening of the irradiated amorphous material. Bubble growth in the low-viscosity material has been approximated by an effective enhanced diffusivity. Mechanisms are included for the radiation-induced softening of the amorphous material, and for a relation between gas atom mobilities and radiation-induced (defect-generated) changes in the material. Results of the analysis indicate that the observed rapid swelling in U 3 Si arises directly from enhanced bubble migration and coalescence due to plastic flow. 34 refs., 11 figs

  9. A study of facilities relative to stabilization of uranium mill tailings at Elliot Lake

    International Nuclear Information System (INIS)

    1983-06-01

    The total project capital cost of facilities to stabilize uranium mill tailings at Elliot Lake while producing 350,000 short tons per year of sulphuric acid and 266,000 short tons per year of triple superphosphate is approximately 153 million dollars. This includes pyrite flotation, roasting, acid and phosphate production, site preparation, utilities and project overhead. A new operating credit of 20.43 dollars per short ton of acid is estimated, achieved from the sale of steam and fertilizer. Two alternatives to the above were also examined, as follows: a) Production of 596,000 short tons per year of acid, and the sale of 246,000 short tons which are in excess of the Elliot Lake mill's requirement. The capital cost of this scheme is approximately 89 million dollars, with a net operating credit of 14.97 dollars per short ton of acid. b) Production of only 350,000 short tons per year of acid. This would entail disposal of the excess pyrite floated from the Rio Algom mills. The capital cost of this scheme is approximately 75 million dollars, with an operating cost of 10.47 dollars per short ton of acid

  10. Thermal cycling behaviour and thermal stability of uranium-molybdenum alloys of low molybdenum content

    International Nuclear Information System (INIS)

    Decours, J.; Fabrique, B.; Peault, O.

    1963-01-01

    We have studied the behaviour during thermal cycling of as-cast U-Mo alloys whose molybdenum content varies from 0.5 to 3 per cent; results are given concerning grain stability during extended heat treatments and the effect of treatments combining protracted heating with thermal cycling. The thermal cycling treatments were carried out at 550, 575, 600 and 625 deg C for 1000 cycles; the protracted heating experiments were done at 550, 575, 600 and 625 deg C for 2000 hours (4000 hrs at 625 deg C). The 0.5 per cent alloy resists much better to the thermal cycling than does the non-alloyed uranium. This resistance is, however, much lower than that of alloys containing over l per cent, even at 550 deg C it improves after a heat treatment for grain-refining. Alloys of over 1.1 per cent have a very good resistance to a cycling treatment even at 625 deg C, and this behaviour improves with increasing concentrations up to 3 per cent. An increase in the temperature up to the γ-phase has few disadvantages provided that it is followed by rapid cooling (50 to 100 deg C/min). The α grain is fine, the γ-phase is of the modular form, and the behaviour during a thermal cycling treatment is satisfactory. If this cooling is slow (15 deg /hr) the α-grain is coarse and cycling treatment behaviour is identical to that of the 0.5 per cent alloy. The protracted heat treatments showed that the α-grain exhibits satisfactory stability after 2000 hours at 575, 600 and 625 deg C, and after 4000 hours at 625 deg C. A heat cycling treatment carried out after these tests affects only very little the behaviour of these alloys during cycling. (authors) [fr

  11. Application of a new technology for reprocessing of wastes within the framework of rehabilitation of uranium mines operated by in situ leaching - 59403

    International Nuclear Information System (INIS)

    Martoyan, Gagik; Nalbandyan, Garik; Gagiyan, Lavrenti; Karamyan, Gagik; Barseghyan, Artak; Brutyan, Gagik

    2012-01-01

    It is essential the environmentally safe industrial production of nuclear fuel especially in the case of uranium extraction by In Situ Leaching, when the environment and the deep extraction of uranium are important problems. In the presented paper it is studied the feasibility of the application of an electro-dialysis method for the deep extraction of uranium and radium from liquid (acid) streams. It is proposed to apply a new electro-hydro-metallurgical [1] extraction and refining method to ensure the necessary extraction level of elements. In the same time the new method ensures the recycling of acids used in the process. The above mentioned two different demonstrations of the new electro-hydro-metallurgical technology show that important environmental problems, such as the removal of harmful liquid-radioactive wastes, are solved in the most economical and energy efficient manner, while a new avenue has also opened for its large-scale use in mining industry. In particular, we offer this method to reprocess the huge quantity of wastes accumulated on uranium mines sites within the rehabilitation work of uranium mines operated by In Situ Leaching. A corresponding electro-hydro-metallurgical plant (mobile and stationary units) is designed for the large-scale extraction and refining of all elements from the wastes of uranium mines, which has a very high level of environmental safety, for an industry that so far has caused considerable environmental harm. The new plant design has no smokestacks, nor the emission of environmentally hazardous elements and its operation is characterized by high energy efficiency, which translates to high economy, while all materials used in the processing stages are fully reconstituted and recycled. (authors)

  12. Push-pull test: a method of evaluating formation adsorption parameters for predicting the environmental effects on in situ coal gasification and uranium recovery

    International Nuclear Information System (INIS)

    Drever, J.I.; McKee, C.R.

    1980-11-01

    The push-pull test, which is a simple injection and pumping sequence of groundwater spiked with solutes of interest, is presented as a method of determining the adsorption characteristics of a formation. Adsorption properties are necessary to predict restoration from both in situ coal gasification and in situ uranium extraction. The major problems in applying laboratory measurements to the field concern scaling the effect of particle size and obtaining representative samples. Laboratory measurements are conducted on gram to kilogram scale samples, whereas the push-pull test evaluates a sample weighing approximately 130 to 1000 metric tons, depending on volume injected and porosity. The problem in translating laboratory results to the field appear to be less severe for sedimentary uranium bodies than for coal. Laboratory measurements are useful in delineating ranges in adsorption properties and in planning the field experiment. Two field push-pull tests were conducted on uranium formations in Wyoming. Adsorption properties estimated from these tests on the basis of a simple cell model were compared to the laboratory values. In the first case, excellent agreement was observed between the values estimated from the field test and the values measured in the laboratory. In the second case, the value for K/sub d/ determined in the laboratory was five times higher than the field value. It is recommended that push-pull tests be conducted on coal formations being considered for in situ gasification in view of the great uncertainty in extrapolating laboratory adsorption properties to the field

  13. Stability investigations of zinc and cobalt precipitates immobilized by in situ bioprecipitation (ISBP) process

    KAUST Repository

    Satyawali, Yamini; Schols, Edo; Van Roy, Sandra; Dejonghe, Winnie; Diels, Ludo; Vanbroekhoven, Karolien

    2010-01-01

    In situ bioprecipitation (ISBP), which involves immobilizing the metals as precipitates (mainly sulphides) in the solid phase, is an effective method of metal removal from contaminated groundwater. This study investigated the stability of metal precipitates formed after ISBP in two different solid-liquid matrices (artificial and natural). The artificial matrix consisted of sand, Zn (200mgL-1), artificial groundwater and a carbon source (electron donor). Here the stability of the Zn precipitates was evaluated by manipulation of redox and pH. The natural system matrices included aquifer material and groundwater samples collected from three different metal (Zn and Co) contaminated sites and different carbon sources were provided as electron donors. In the natural matrices, metal precipitates stability was assessed by changing aquifer redox conditions, sequential extraction, and BIOMET® assay. The results indicated that, in the artificial matrix, redox manipulation did not impact the Zn precipitates. However the sequential pH change proved detrimental, releasing 58% of the precipitated Zn back into liquid phase. In natural matrices, the applied carbon source largely affected the stability of metal precipitates. Elemental analysis performed on the precipitates formed in natural matrix showed that the main elements of the precipitates were sulphur with Zn and Co. © 2010 Elsevier B.V.

  14. Ultra-Small Fatty Acid-Stabilized Magnetite Nanocolloids Synthesized by In Situ Hydrolytic Precipitation

    Directory of Open Access Journals (Sweden)

    Kheireddine El-Boubbou

    2015-01-01

    Full Text Available Simple, fast, large-scale, and cost-effective preparation of uniform controlled magnetic nanoparticles remains a major hurdle on the way towards magnetically targeted applications at realistic technical conditions. Herein, we present a unique one-pot approach that relies on simple basic hydrolytic in situ coprecipitation of inexpensive metal salts (Fe2+ and Fe3+ compartmentalized by stabilizing fatty acids and aided by the presence of alkylamines. The synthesis was performed at relatively low temperatures (~80°C without the use of high-boiling point solvents and elevated temperatures. This method allowed for the production of ultra-small, colloidal, and hydrophobically stabilized magnetite metal oxide nanoparticles readily dispersed in organic solvents. The results reveal that the obtained magnetite nanoparticles exhibit narrow size distributions, good monodispersities, high saturation magnetizations, and excellent colloidal stabilities. When the [fatty acid] : [Fe] ratio was varied, control over nanoparticle diameters within the range of 2–10 nm was achieved. The amount of fatty acid and alkylamine used during the reaction proved critical in governing morphology, dispersity, uniformity, and colloidal stability. Upon exchange with water-soluble polymers, the ultra-small sized particles become biologically relevant, with great promise for theranostic applications as imaging and magnetically targeted delivery vehicles.

  15. Stability investigations of zinc and cobalt precipitates immobilized by in situ bioprecipitation (ISBP) process

    KAUST Repository

    Satyawali, Yamini

    2010-09-01

    In situ bioprecipitation (ISBP), which involves immobilizing the metals as precipitates (mainly sulphides) in the solid phase, is an effective method of metal removal from contaminated groundwater. This study investigated the stability of metal precipitates formed after ISBP in two different solid-liquid matrices (artificial and natural). The artificial matrix consisted of sand, Zn (200mgL-1), artificial groundwater and a carbon source (electron donor). Here the stability of the Zn precipitates was evaluated by manipulation of redox and pH. The natural system matrices included aquifer material and groundwater samples collected from three different metal (Zn and Co) contaminated sites and different carbon sources were provided as electron donors. In the natural matrices, metal precipitates stability was assessed by changing aquifer redox conditions, sequential extraction, and BIOMET® assay. The results indicated that, in the artificial matrix, redox manipulation did not impact the Zn precipitates. However the sequential pH change proved detrimental, releasing 58% of the precipitated Zn back into liquid phase. In natural matrices, the applied carbon source largely affected the stability of metal precipitates. Elemental analysis performed on the precipitates formed in natural matrix showed that the main elements of the precipitates were sulphur with Zn and Co. © 2010 Elsevier B.V.

  16. Bacterial Community Succession During in situ Uranium Bioremediation: Spatial Similarities Along Controlled Flow Paths

    International Nuclear Information System (INIS)

    Hwang, Chiachi; Wu, Weimin; Gentry, Terry J.; Carley, Jack; Corbin, Gail A.; Carroll, Sue L.; Watson, David B.; Jardine, Phil M.; Zhou, Jizhong; Criddle, Craig S.; Fields, Matthew W.

    2009-01-01

    Bacterial community succession was investigated in a field-scale subsurface reactor formed by a series of wells that received weekly ethanol additions to re-circulating groundwater. Ethanol additions stimulated denitrification, metal reduction, sulfate reduction, and U(VI) reduction to sparingly soluble U(IV). Clone libraries of SSU rRNA gene sequences from groundwater samples enabled tracking of spatial and temporal changes over a 1.5 y period. Analyses showed that the communities changed in a manner consistent with geochemical variations that occurred along temporal and spatial scales. Canonical correspondence analysis revealed that the levels of nitrate, uranium, sulfide, sulfate, and ethanol strongly correlated with particular bacterial populations. As sulfate and U(VI) levels declined, sequences representative of sulfate-reducers and metal-reducers were detected at high levels. Ultimately, sequences associated with sulfate-reducing populations predominated, and sulfate levels declined as U(VI) remained at low levels. When engineering controls were compared to the population variation via canonical ordination, changes could be related to dissolved oxygen control and ethanol addition. The data also indicated that the indigenous populations responded differently to stimulation for bio-reduction; however, the two bio-stimulated communities became more similar after different transitions in an idiosyncratic manner. The strong associations between particular environmental variables and certain populations provide insight into the establishment of practical and successful remediation strategies in radionuclide-contaminated environments with respect to engineering controls and microbial ecology.

  17. Bacterial Community Succession During in situ Uranium Bioremediation: Spatial Similarities Along Controlled Flow Paths

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Chiachi; Wu, Weimin; Gentry, Terry J.; Carley, Jack; Corbin, Gail A.; Carroll, Sue L.; Watson, David B.; Jardine, Phil M.; Zhou, Jizhong; Criddle, Craig S.; Fields, Matthew W.

    2009-05-22

    Bacterial community succession was investigated in a field-scale subsurface reactor formed by a series of wells that received weekly ethanol additions to re-circulating groundwater. Ethanol additions stimulated denitrification, metal reduction, sulfate reduction, and U(VI) reduction to sparingly soluble U(IV). Clone libraries of SSU rRNA gene sequences from groundwater samples enabled tracking of spatial and temporal changes over a 1.5 y period. Analyses showed that the communities changed in a manner consistent with geochemical variations that occurred along temporal and spatial scales. Canonical correspondence analysis revealed that the levels of nitrate, uranium, sulfide, sulfate, and ethanol strongly correlated with particular bacterial populations. As sulfate and U(VI) levels declined, sequences representative of sulfate-reducers and metal-reducers were detected at high levels. Ultimately, sequences associated with sulfate-reducing populations predominated, and sulfate levels declined as U(VI) remained at low levels. When engineering controls were compared to the population variation via canonical ordination, changes could be related to dissolved oxygen control and ethanol addition. The data also indicated that the indigenous populations responded differently to stimulation for bio-reduction; however, the two bio-stimulated communities became more similar after different transitions in an idiosyncratic manner. The strong associations between particular environmental variables and certain populations provide insight into the establishment of practical and successful remediation strategies in radionuclide-contaminated environments with respect to engineering controls and microbial ecology.

  18. Ground-water elements of in situ leach mining of uranium. Final report

    International Nuclear Information System (INIS)

    Thompson, W.E.; Swarzenski, W.V.; Warner, D.L.; Rouse, G.E.; Carrington, O.F.; Pyrih, R.Z.

    1978-07-01

    This report provides methods to collect data and evaluates impacts concerning ground-water elements of production-scale leach mining of uranium. Two overlapping networks of monitor wells are designed to collect premining hydrogeologic and baseline water-quality data and to detect excursions of leaching fluids. The pre-mining data collection network consists of 24 wells completed into the ore-zone aquifer and the water-bearing units above and below it. The excursion-monitor network utilizes two rings of wells encircling the ore body and other wells strategically placed into other water-bearing units. The lateral excursion detection system is keyed to changes in water levels whereas the vertical excursion detection system is keyed to changes in water quality. Several ground-water restoration methods are evaluated. Mechanical and chemical restoration methods can significantly remove most introduced and mobilized chemicals. Natural geochemical mechanisms should be capable of causing water-quality improvement. Several water-quality constituents, i.e., ammonia, chloride, sulfate, may not be greatly affected by restoration efforts. Most mining and restoration activities should not greatly affect the availability or usefulness of ground water unless uncontrolled withdrawals from many sources occur. Disposal of leach mining wastes may prove a greater threat to the environment than the mining. Natural conditions and/or current state and Federal regulations limit the types of disposal methods that may be used

  19. In-situ removal and characterisation of uranium-containing particles from sediments surrounding the Fukushima Daiichi Nuclear Power Plant

    Science.gov (United States)

    Martin, P. G.; Griffiths, I.; Jones, C. P.; Stitt, C. A.; Davies-Milner, M.; Mosselmans, J. F. W.; Yamashiki, Y.; Richards, D. A.; Scott, T. B.

    2016-03-01

    Traditional methods to locate and subsequently study radioactive fallout particles have focused heavily on autoradiography coupled with in-situ analytical techniques. Presented here is the application of a Variable Pressure Scanning Electron Microscope with both backscattered electron and energy dispersive spectroscopy detectors, along with a micromanipulator setup and electron-hardening adhesive to isolate and remove individual particles before synchrotron radiation analysis. This system allows for a greater range of new and existing analytical techniques, at increased detail and speed, to be applied to the material. Using this method, it was possible to erform detailed energy dispersive spectroscopy and synchrotron radiation characterisation of material likely ejected from the Fukushima Daiichi Nuclear Power Plant found within a sediment sample collected from the edge of the 30 km exclusion zone. Particulate material sub-micron in maximum dimension examined during this work via energy dispersive spectroscopy was observed to contain uranium at levels between 19.68 and 28.35 weight percent, with the application of synchrotron radiation spectroscopy confirming its presence as a major constituent. With great effort and cost being devoted to the remediation of significant areas of eastern Japan affected by the incident, it is crucial to gain the greatest possible understanding of the nature of this contamination in order to inform the most appropriate clean-up response.

  20. Feasibility of using fluorescence in situ hybridization (FISH) to detect early gene changes in sputum cells from uranium miners

    Energy Technology Data Exchange (ETDEWEB)

    Neft, R.E.; Rogers, J.L.; Belinsky, S.A. [and others

    1995-12-01

    Epidemiological studies have shown that combined exposure to radon progeny and tobacco smoke produce a greater than additive or synergistic increase in lung cancer risk. Lung cancer results from multiple genetic changes over a long period of time. An early change that occurs in lung cancer is trisomy 7 which is found in 50% of non-small cell lung cancer and in the far margins of resected lung tumors. The 80% mortality associated with lung cancer is in part related to the high proportion of patients who present with an advanced, unresectable tumor. Therefore, early detection of patients at risk for tumor development is critical to improve treatment of this disease. Currently, it is difficult to detect lung cancer early while it is still amendable by surgery. Saccomanno, G. has shown that premalignant cytologic changes in sputum cells collected from uranium miners can be detected by a skilled, highly trained cytopathologist. A more objective alternative for identifying premalignant cells in sputum may be to determine whether an early genetic change such as trisomy 7 is present in these cells. Fluorescence in situ hybridization (FISH) can be used to identify cells with trisomy 7. The results of this investigation indicate that FISH may prove to be an accurate, efficient method to test at-risk individuals for genetic alterations in bronchial epithelial cells from sputum.

  1. Feasibility of using fluorescence in situ hybridization (FISH) to detect early gene changes in sputum cells from uranium miners

    International Nuclear Information System (INIS)

    Neft, R.E.; Rogers, J.L.; Belinsky, S.A.

    1995-01-01

    Epidemiological studies have shown that combined exposure to radon progeny and tobacco smoke produce a greater than additive or synergistic increase in lung cancer risk. Lung cancer results from multiple genetic changes over a long period of time. An early change that occurs in lung cancer is trisomy 7 which is found in 50% of non-small cell lung cancer and in the far margins of resected lung tumors. The 80% mortality associated with lung cancer is in part related to the high proportion of patients who present with an advanced, unresectable tumor. Therefore, early detection of patients at risk for tumor development is critical to improve treatment of this disease. Currently, it is difficult to detect lung cancer early while it is still amendable by surgery. Saccomanno, G. has shown that premalignant cytologic changes in sputum cells collected from uranium miners can be detected by a skilled, highly trained cytopathologist. A more objective alternative for identifying premalignant cells in sputum may be to determine whether an early genetic change such as trisomy 7 is present in these cells. Fluorescence in situ hybridization (FISH) can be used to identify cells with trisomy 7. The results of this investigation indicate that FISH may prove to be an accurate, efficient method to test at-risk individuals for genetic alterations in bronchial epithelial cells from sputum

  2. In situ studies of uranium-plutonium mixed oxides. Influence of composition on phase equilibria and thermodynamic properties

    International Nuclear Information System (INIS)

    Strach, Michal

    2015-01-01

    Due to their physical and chemical properties, mixed uranium-plutonium oxides are considered for fuel in 4. generation nuclear reactors. In this frame, complementary experimental studies are necessary to develop a better understanding of the phenomena that take place during fabrication and operation in the reactor. The focus of this work was to study the U-Pu-O phase diagram in a wide range of compositions and temperatures to ameliorate our knowledge of the phase equilibria in this system. Most of experiments were done using in situ X-ray diffraction at elevated temperatures. The control of the oxygen partial pressure during the treatments made it possible to change the oxygen stoichiometry of the sample, which gave us an opportunity to study rapidly different compositions and the processes involved. The experimental approach was coupled with thermodynamic modeling using the CALPHAD method, to precisely plan the experiments and interpret the obtained results. This approach enabled us to enhance the knowledge of phase equilibria in the U-Pu-O system. (author) [fr

  3. Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Falls City, Texas

    International Nuclear Information System (INIS)

    Chernoff, A.R.; Lacker, D.K.

    1992-09-01

    The uranium processing site near Falls City, Texas, was one of 24 inactive uranium mill sites designated to be remediated by the US Department of Energy (DOE) under Title I of the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). The UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE's remedial action plan (RAP) and certify that the remedial action conducted at the site complies with the standards promulgated by the US Environmental Protection Agency (EPA). The RAP, which includes this summary remedial action selection report (RAS), serves a two-fold purpose. First, it describes the activities proposed by the DOE to accomplish long-term stabilization and control of the residual radioactive materials at the inactive uranium processing site near Falls City, Texas. Second, this document and the remainder of the RAP, upon concurrence and execution by the DOE, the State of Texas, and the NRC, becomes Appendix B of the Cooperative Agreement between the DOE and the State of Texas

  4. Remedial action plan and site design for stabilization of the inactive uranium processing site at Naturita, Colorado

    International Nuclear Information System (INIS)

    1993-08-01

    The uranium processing site near Naturita, Colorado, is one of 24 inactive uranium mill sites designated to be cleaned up by the US Department of Energy (DOE) under the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), Public Law 95-604. Part of the UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE's remedial action plan (RAP) and certify that the remedial action conducted at the site complies with the standards promulgated by the US Environmental Protection Agency (EPA). Included in the RAP is this Remedial Action Selection Report (RAS), which serves two purposes. First, it describes the activities that are proposed by the DOE to accomplish remediation and long-term stabilization and control of the radioactive materials at the inactive uranium processing site near Naturita, Colorado. Second, this document and the rest of the RAP, upon concurrence and execution by the DOE, the state of Colorado, and the NRC, become Appendix B of the cooperative agreement between the DOE and the State of Colorado

  5. Monitoring the in-situ oxide growth on uranium by ultraviolet-visible reflectance spectroscopy

    Science.gov (United States)

    Schweke, Danielle; Maimon, Chen; Chernia, Zelig; Livneh, Tsachi

    2012-11-01

    We demonstrate the in-situ monitoring of oxide growth on U-0.1 wt. % Cr by means of UV-visible reflectance spectroscopy in the thickness range of ˜20-150 nm. Two different approaches are presented: In the "modeling approach," we employ a model for a metallic substrate covered by a dielectric layer, while taking into account the buildup of oxygen gradient and surface roughness. Then, we fit the simulated spectra to the experimental one. In the "extrema analysis," we derive an approximated analytical expression, which relates the oxide thickness to the position of the extrema in the reflectance spectra based on the condition for optical interference of the reflected light. Good agreement is found between the values extracted by the two procedures. Activation energy of ˜21 kcal/mole was obtained by monitoring the oxide growth in the temperature range of 22-90 °C. The upper bound for the thickness determination is argued to be mostly dictated by cracking and detachment processes in the formed oxide.

  6. Uranium resource technology, Seminar 3, 1980

    International Nuclear Information System (INIS)

    Morse, J.G.

    1980-01-01

    This conference proceedings contains 20 papers and 1 panel discussion on uranium mining and ore treatment, taking into account the environmental issues surrounding uranium supply. Topics discussed include: the US uranium resource base, the technology and economics of uranium recovery from phosphate resources, trends in preleash materials handling of sandstone uranium ores, groundwater restoration after in-situ uranium leaching, mitigation of the environmental impacts of open pit and underground uranium mining, remedial actions at inactive uranium mill tailings sites, environmental laws governing in-situ solution mining of uranium, and the economics of in-situ solution mining. 16 papers are indexed separately

  7. Stability of silver nanoparticle monolayers determined by in situ streaming potential measurements

    International Nuclear Information System (INIS)

    Morga, Maria; Adamczyk, Zbigniew; Oćwieja, Magdalena

    2013-01-01

    A silver particle suspension obtained by a chemical reduction was used in this work. Monolayers of these particles (average size 28 nm) on mica modified by poly(allylamine hydrochloride) were produced under diffusion-controlled transport. Monolayer coverages, quantitatively determined by atomic force microscopy (AFM) and SEM, was regulated by adjusting the nanoparticle deposition time and the suspension concentration. The zeta potential of the monolayers was determined by streaming potential measurements carried out under in situ (wet) conditions. These measurements performed for various ionic strengths and pH were interpreted in terms of the three-dimensional (3D) electrokinetic model. The stability of silver monolayers was also investigated using streaming potential and the AFM methods. The decrease in the surface coverage of particles as a function of time and ionic strength varied between 10 −1 and 10 −4  M was investigated. This allowed one to determine the equilibrium adsorption constant K a and the binding energy of silver particles (energy minima depth). Energy minima depth were calculated that varied between −18 kT for I = 10 −1  M and −19 kT for I = 10 −4 for pH 5.5 and T = 298 K. Our investigations suggest that the interactions between surface and nanoparticles are controlled by the electrostatic interactions among ion pairs. It was also shown that the in situ electrokinetic measurements are in accordance with those obtained by more tedious ex situ AFM measurements. This confirmed the utility of the streaming potential method for direct kinetic studies of nanoparticle deposition/release processes.Graphical Abstract

  8. Soil surface stabilization using an in situ plutonium coating techniuqe at the Nevada Test Site

    International Nuclear Information System (INIS)

    Lew, J.; Snipes, R.; Tamura, T.

    1996-01-01

    The Hazardous Waste Remedial Actions Program (HAZWRAP), in collaboration with the University of Nevada at Reno (UNR), has developed and is investigating an in situ plutonium treatment for soils at the Nevada Test Site (NTS). The concept, conceived by Dr. T. Tamura and refined at HAZWRAP, was developed during the Nevada Applied Ecology Program investigation. In analyzing for plutonium in soils, it was noted that the alpha emanation of plutonium was greatly attenuated if traces of iron or manganese oxides were present in the final electroplating stage. The technique would reduce resuspension of alpha particles into the air by coating the contaminants in soils in situ with an environmentally compatible, durable, and nontoxic material. The coating materials (calcium hydroxide, ferrous sulfate) reduce resuspension by providing a cementitious barrier against radiation penetration while retaining soil porosity. This technique not only stabilizes plutonium-contaminated soils, but also provides an additional protection from worker exposure to radiation during remediation activities. Additionally, the coating would decrease the water solubility of the contaminant and, thus, reduce its migration through soil and uptake by plants

  9. Stability of added and in situ-produced vitamin B12 in breadmaking.

    Science.gov (United States)

    Edelmann, Minnamari; Chamlagain, Bhawani; Santin, Marco; Kariluoto, Susanna; Piironen, Vieno

    2016-08-01

    Vitamin B12 exists naturally in foods of animal origin and is synthesised only by certain bacteria. New food sources are needed to ensure vitamin B12 intake in risk groups. This study aimed to investigate the stability of added cyanocobalamin (CNCbl, chemically modified form) and hydroxocobalamin (OHCbl, natural form) and in situ-synthesised vitamin B12 in breadmaking. Samples were analysed both with a microbiological (MBA) and a liquid chromatographic (UHPLC) method to test applicability of these two methods. Proofing did not affect CNCbl and OHCbl levels. By contrast, 21% and 31% of OHCbl was lost in oven-baking steps in straight- and sponge-dough processes, respectively, whereas CNCbl remained almost stable. In sourdough baking, 23% of CNCbl and 44% of OHCbl were lost. In situ-produced vitamin B12 was almost as stable as added CNCbl and more stable than OHCbl. The UHPLC method showed its superiority to the MBA in determining the active vitamin B12. Copyright © 2016. Published by Elsevier Ltd.

  10. Shape-and size-controlled Ag nanoparticles stabilized by in situ generated secondary amines

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez-Meneses, E., E-mail: esther.ramirez@ibero.mx [Departamento de Ingeniería y Ciencias Químicas, Universidad Iberoamericana, Prolongación Paseo de la Reforma 880, Lomas de Santa Fe, Distrito Federal C.P. 01219 (Mexico); Montiel-Palma, V. [Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001 Col. Chamilpa, Cuernavaca, Morelos C.P. 62209 (Mexico); Domínguez-Crespo, M.A.; Izaguirre-López, M.G. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada-IPN, Unidad Altamira. Km 14.5 Carretera Tampico-Puerto Industrial, 89600 Altamira, Tamaulipas (Mexico); Palacios-Gonzalez, E. [Laboratorio de Microscopia de Ultra alta Resolución, Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas No. 152, C.P. 07730 México D.F. (Mexico); Dorantes-Rosales, H. [Departamento de Metalurgia, E.S.I.Q.I.E.-I.P.N., Unidad Profesional Adolfo López Mateos, Zacatenco, Delegación. Gustavo A. Madero, C.P. 07738 México D.F. (Mexico)

    2015-09-15

    Highlights: • Ag nanoparticles were generated from Ag amido complexes AgN{sup i}Pr{sub 2} and AgN(SiMe{sub 3}){sub 2}. • Ag nanoparticles were stabilized by in situ generated HN{sup i}Pr{sub 2} or HN(SiMe{sub 3}){sub 2}. • 1 or 5 equiv. of ethylenediamine as additional capping agent decreases the average size of the particles. • Ethylenediamine favor the formation of spherical particles. - Abstract: Silver amides such as AgN{sup i}Pr{sub 2} and AgN(SiMe{sub 3}){sub 2} have been employed successfully as precursors for the yield synthesis of silver nanoparticles under mild conditions of dihydrogen gas reduction (2 atm) in organic media. Transmission electron microscopy (TEM) showed the formation of silver nanoparticles with FCC structure, variously sized from 26 to 35 nm for AgN{sup i}Pr{sub 2} and from 14 to 86 nm for AgN(SiMe{sub 3}){sub 2}, the synthesis could take place in absence of added stabilizers due to the in situ formation of secondary amines from the reaction of dihydrogen gas with the amide ligands of the silver precursor. Indeed, the presence of HNR{sub 2} (R = iPr{sub 2}, N(SiMe{sub 3}){sub 2}) on the surface of the nanoparticle was confirmed by spectroscopic means. Finally, the addition of ethylenediamine as additional capping agent allowed not only the control of the structural characteristics of the resulting Ag nanoparticles (well-dispersed with spherical shape), but that regarding the nanoparticle size as it inhibited overgrowth, limiting it to ca. 25 nm.

  11. In situ crosslinking of surface-initiated ring opening metathesis polymerization of polynorbornene for improved stability.

    Science.gov (United States)

    Fursule, Ishan A; Abtahi, Ashkan; Watkins, Charles B; Graham, Kenneth R; Berron, Brad J

    2018-01-15

    In situ crosslinking is expected to increase the solvent stability of coatings formed by surface-initiated ring opening metathesis polymerization (SI ROMP). Solvent-associated degradation limits the utility of SI ROMP coatings. SI ROMP coatings have a unique capacity for post-functionalization through reaction of the unsaturated site on the polymer backbone. Any post-reaction scheme which requires a liquid solvent has the potential to degrade the coating and lower the thickness of the resulting film. We designed a macromolecular crosslinking group based on PEG dinorbornene. The PEG length is tailored to the expected mean chain to chain distance during surface-initiated polymerization. This crosslinking macromer is randomly copolymerized with norbornene through SI ROMP on a gold coated substrate. The solvent stability of polynorbornene coatings with and without PEG dinorbornene is quantitatively determined, and the mechanism of degradation is further supported through XPS and AFM analyses. The addition of the 0.25mol% PEG dinorbornene significantly increases the solvent stability of the SI ROMP coatings. The crosslinker presence in the more stable films is supported with observable PEG absorbances by FTIR and an increase in contact angle hysteresis when compared to non-crosslinked coatings. The oxidation of the SI ROMP coatings is supported by the observation of carbonyl oxygen in the polynorbornene coatings. The rapid loss of the non-crosslinked SI ROMP coating corresponds to nanoscale pitting across the surface and micron-scale regions of widespread film loss. The crosslinked coatings have uniform nanoscale pitting, but the crosslinked films show no evidence of micron-scale film damage. In all, the incorporation of minimal crosslinking content is a simple strategy for improving the solvent stability of SI ROMP coatings. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Discussion on some problems concerned the origin of hydrothermal uranium deposit from the point of remelting in situ view

    International Nuclear Information System (INIS)

    Zhang Ke

    2001-01-01

    The authors try to discuss some problems concerned the origin of hydrothermal uranium (U) deposit from the point of remelting in situ view about granite formation. The problems include the time differences between mineralization and country rock (granite), characteristics, differences between 'large granite bodies' and 'small granite bodies', granite discriminant that is used to judge whether or not granite produce U deposit as well as relationship of U mineralization to W(Sn), Nd, Ta mineralization, red beds and tectonic movements. According to the theory of remelting in situ, granite bodies in the same period that can be investigated are actual doming portions of the same remelting layer, which had be so stripped by erosion that granite bodies rustled. Thus the size variation of granite bodies implies only the fact of different erosion levels. Since U always moves in long distance with hydrothermal solution from its parent granite, it always deposits in outer contact zone, which, as a kind of country rock, might be sedimentary rock (including red bed), metamorphic rock, of early period granite. The two former situations indicate less erosion levels (small granite bodies) while the later situation indicates larger erosion levels (large granite bodies). Because the country rock of later is granite, an illusion of large time difference between mineralization related granite and granite might be made. Also, there is no direct and simple connection between U mineralization and discriminant which is calculated from primary chemical composition of granite and has been unsuccessfully used as an index to judge whether of not a granite body would produce U mineralization because in this situation the granite is only country rock. Besides, the U mineralization is later than the one of W(Sn), Nd, Ta in general so that it often relate to 'large granite bodies', in which 'mineralization crust' is lower than the one of W(Sn), Nd, Ta and mineral composition is relatively simple

  13. Former uranium mine-induced effects in caged roach: a multiparametric approach for the evaluation of in situ metal toxicity.

    Science.gov (United States)

    Gagnaire, Béatrice; Bado-Nilles, Anne; Betoulle, Stéphane; Amara, Rachid; Camilleri, Virginie; Cavalié, Isabelle; Chadili, Edith; Delahaut, Laurence; Kerambrun, Elodie; Orjollet, Daniel; Palluel, Olivier; Sanchez, Wilfried

    2015-01-01

    To characterize environmental risks linked to former uranium mines in the Limousin region of France, a study was conducted on fish health effects from uranium releases. Two private ponds were compared in this study, one with uranium contamination and one background site, upstream of the mining zone. Roach, Rutilus rutilus, were caged for 28 days in both ponds. Physico-chemical parameters of water and sediments and bioaccumulation of metals in several organs were determined. After 14 and 28 days of caging, immune, oxidative stress, biotransformation, neurotoxicity and physiological parameters were measured. Iron and aluminium were quantified in the water of both sites; however, barium and manganese were only present in the water of the uranium contaminated site. Uranium was present in both sites but at very different concentrations. The sediments from the uranium contaminated site contained high levels of radioactive elements coming from the disintegration chain of uranium. Results of biological parameters indicated stimulation of immune parameters and of oxidative stress and a decrease of AChE in fish caged in the uranium contaminated pond compared to the uranium-free pond. Overall, the results determined roach health status in the context of pollution from poly-metallic mining. The data strengthen our knowledge of the environmental risk assessment associated with radioactive substances in the environment.

  14. Removal of Trace Elements by Cupric Oxide Nanoparticles from Uranium In Situ Recovery Bleed Water and Its Effect on Cell Viability

    Science.gov (United States)

    Schilz, Jodi R.; Reddy, K. J.; Nair, Sreejayan; Johnson, Thomas E.; Tjalkens, Ronald B.; Krueger, Kem P.; Clark, Suzanne

    2015-01-01

    In situ recovery (ISR) is the predominant method of uranium extraction in the United States. During ISR, uranium is leached from an ore body and extracted through ion exchange. The resultant production bleed water (PBW) contains contaminants such as arsenic and other heavy metals. Samples of PBW from an active ISR uranium facility were treated with cupric oxide nanoparticles (CuO-NPs). CuO-NP treatment of PBW reduced priority contaminants, including arsenic, selenium, uranium, and vanadium. Untreated and CuO-NP treated PBW was used as the liquid component of the cell growth media and changes in viability were determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay in human embryonic kidney (HEK 293) and human hepatocellular carcinoma (Hep G2) cells. CuO-NP treatment was associated with improved HEK and HEP cell viability. Limitations of this method include dilution of the PBW by growth media components and during osmolality adjustment as well as necessary pH adjustment. This method is limited in its wider context due to dilution effects and changes in the pH of the PBW which is traditionally slightly acidic however; this method could have a broader use assessing CuO-NP treatment in more neutral waters. PMID:26132311

  15. Powder metallurgical nanostructured medium carbon bainitic steel: Kinetics, structure, and in situ thermal stability studies

    Energy Technology Data Exchange (ETDEWEB)

    Lonardelli, I., E-mail: il244@cam.ac.uk [University of Cambridge, Materials Science and Metallurgy, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); University of Trento, Materials Engineering and Industrial Technologies, via Mesiano 77, 38123 Trento (Italy); Bortolotti, M. [Fondazione Bruno Kessler, via Sommarive 18, 38123 Trento (Italy); Beek, W. van [Swiss-Norwegian Beamlines, ESRF, BP 220, 38043 Grenoble Cedex (France); Girardini, L.; Zadra, M. [K4-Sint, via Dante 300, 38057 Pergine Valsugana (Italy); Bhadeshia, H.K.D.H. [University of Cambridge, Materials Science and Metallurgy, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)

    2012-10-15

    It has been possible to produce incredibly fine plates of bainitic ferrite separated by a percolating network of retained austenite in a medium carbon steel produced by mechanical alloying followed by spark plasma sintering and isothermal heat treatment. This is because the sintering process limits the growth of the austenite grains to such an extent that the martensite-start temperature is suppressed in spite of the medium carbon concentration. Furthermore, the fine austenite grain size accelerates the bainite transformation, which can therefore be suppressed to low temperatures to obtain a nanostructure. Microscopy and in situ synchrotron X-ray diffraction were used to investigate the morphology and the thermal stability of the retained austenite during continuous heating. These latter experiments revealed a gradient of carbon concentration in the retained austenite and a reduced thermal stability in high carbon film-austenite. It was also possible to correlate the evolution of defect density and carbon depletion in both retained austenite and bainitic ferrite during tempering.

  16. In-situ stabilization of the Geiger (C and M Oil) Superfund Site

    International Nuclear Information System (INIS)

    Andromalos, K.B.; Ameel, M.E.

    1994-01-01

    The Geiger (C and M Oil) Superfund Site is the first US Army Corps of Engineers managed soil remediation project which utilized the in-situ stabilization/solidification technique to remediate the soil. This project involved the remediation of approximately 23,000 cubic yards of contaminated soil. Contaminants of concern included chromium, lead, PCB'S, toluene, benzene, and other organic compounds. Clean-up criteria for the stabilized material was equal to the National Primary Drinking Water Regulations, when tested using the TCLP leachate extraction method. Chromium, lead, and toluene were the main contaminants of concern, with TCLP clean-up goals of 150, 15 and 1,000 parts per billion (ppb), respectively. This National Priorities List (NPL) site is located near Charleston, SC and was an abandoned old waste oil facility that utilized unlined shallow trenches for the storage of waste oil. This paper summarizes the initial testing programs and the final production work at the site. Extensive testing was performed throughout all phases of the project. This testing was performed for the purpose of mix optimization, quality assurance, and verification testing. Specific parameters tested included: TCLP testing of organics, metals and PCBs, permeability testing, and unconfirmed compression strength

  17. Remedial Action Plan and final design for stabilization of the inactive uranium mill tailings at Green River, Utah

    International Nuclear Information System (INIS)

    Matthews, M.L.; Alkema, K.

    1991-03-01

    This Remedial Action Plan (RAP) has been developed to serve a threefold purpose. It presents the series of activities that are proposed by the US Department of Energy (DOE) to accomplish long-term stabilization and control of radioactive materials at the inactive uranium processing site located near Green River, Utah. It provides a characterization of the present conditions of the site. It also serves to document the concurrence of the state of Utah and the US Nuclear Regulatory Commission (NRC) in the remedial action. This agreement, upon execution by the DOE and the state of Utah, and concurrence by the NRC, becomes Appendix 8 of the Cooperative Agreement

  18. Exploration for in situ leach amenable sandstone uranium deposits and their impact on the environment in China

    International Nuclear Information System (INIS)

    Zhang Weixing

    2002-01-01

    Taking the No. 512 uranium deposit in YiLi Basin, Xinjiang as an example, this paper describes the ore-forming geological settings of inter-layer oxidizing zone roll-front type of ISL amenable uranium deposits. It also summarizes the different exploration methods used during various stages of exploration. The paper also introduces the Dabu uranium deposit in Taoshan, Jiangxi, which is amenable to the in-place-leach mining method. It probes into the possibilities for transforming non-economic and sub-economic uranium deposits into economical and minable ones. In addition, the paper emphasizes that ISL uranium mining, when compared with conventional mining, plays an active role in reducing environmental contamination and restoring ecological balance. (author)

  19. Lab scale testing of novel natural analog in situ stabilization agents

    International Nuclear Information System (INIS)

    Shaw, P.

    1997-01-01

    This report summarizes the laboratory-scale test results on several novel in situ treatment and stabilization agents for buried hazardous and radioactive waste. Paraffin, hematite and phosphate materials were examined when combined with soil and other wastes representative of what might be present at buried waste DOE sites. Hematite was made from the reaction of agricultural iron and lime slurries to form gypsum and iron oxide/hydroxide. Common household paraffin was melted, both with and without a zeolitic additive, waste added and then cooled. Magnesium phosphate was made from the reaction of magnesium oxide and phosphoric acid or potassium biphosphate to form, magnesium phosphate. All were tested with soil and some with additional waste sumulants such as ash, machine oil and nitrate salts. The following laboratory-generated data indicate that all waste encapsulation materials tested are appropriate materials, for field in situ testing. Compressive strengths of treated Idaho National Engineering and Environment Laboratory (INEEL) soil and the waste encapsulation material were sufficient to prevent collapse of the void space in waste, i.e., greater than the NRC 60 psi minimum. The mineralogy and microstructure of hematite was amorphous but should progress to an interlocking crystalline solid. Phosphate was crystalline with characteristics of higher temperature ceramics. Paraffin is non crystalline but encapsulates even very fine grained INEEL soils. Each agent appears to be chemically and physically inert to possible waste materials such as, nitrates and machine cutting oil. Two of the agents hematite and phosphate react favorably with ash increasing the metals retention at higher waste loadings than Portland cement. Hematite, phosphate and zeolite decrease leaching of most hazardous metals from waste when compared to untreated waste and soil. Solution pH, time for reaction initiation, and viscosity values are conducive to jet-grouting application

  20. A preliminary analysis and assessment of hydrogeological conditions for in-situ leach mining of sandstone-type uranium deposit in northern Ordos basin

    International Nuclear Information System (INIS)

    Chen Fazheng; Zhao Jinfeng; Chang Baocheng; Gao Junyi

    2006-01-01

    A systematic analysis and assessment on hydrogeologic condition, the lithology and hydrogeologic structure of ore-hosting aquitfers, hydrodynamic condition, hydrochemical characteristics at a sandstone-type uranium deposit in northern Ordos basin is made in this paper. It has been concluded, that hydrogeologic condition in the study area is favorable, meeting the requirements for in-situ leach mining of the deposit. Aimed at the low artesian pressure head and low water output and based on the results of pumping-injection tests which led to the significant increase of water output, a technical scheme of pressured water injection has been proposed to artificially raise the artesian pressure head and increase the output of groundwater to satisfy the requirements of in-situ leach mining. (authors)

  1. Some problems on target-area selection for searching interstratified infiltration sandstone-type uranium deposits suitable to in-situ leaching

    International Nuclear Information System (INIS)

    Hu Shaokang

    2005-01-01

    The sandstone-type uranium deposits are widely distributed in the world, but only 3 regions where deposits reach uranium province size and are suitable for in-situ leaching have been found. Deposits are all of the interstratified-oxidation type, and developed at the combination sites of the most recent orogenic belt with young or old platforms in form of 'branching, inclining and disappearing' of the former. Geomorphologically, these regions consist of 3 big 'steps' from high mountain regions through lower mountains or hills to the margins of the basin, which are in form of declining slope and form a good hydrodynamic conditions. Climatically, an arid climate was always required for the period of sandstone-type uranium ore formation, while annual evaporation is higher than the annual precipitation, the high mountain regions with high potential energy of water melted from glacier and snow which is thought to be a long-term and steady underground water supplier for lower mountains or hill regions and the margins of the basin. However, in orogenic belt there is a good number of inter-mountain basins with at least two big 'steps' indicating a good potential to discover interstratified-oxidation sandstone-type uranium deposits in coal-bearing basins. Many Chinese and foreign uranium geologists have noticed that there is an east-west oriented Hercynian uranium mineralization belt lying across the middle of Europe, the eastern section is superimposed on the Ural-Tianshan-Mongolian mobile belt and together with the latter it was infected by the Alpine-Himalayan movement in Meso-Cenozoic. This resulted in a complicated metallogenic scene with different ore-forming times, multiple types of deposits, and spatial concentration. In addition, a sub-meridional-oriented 'Vebris belt' running through the eastern part of Asia is considered as combination part of the Central Asian mobile belt with the Western Pacific mobile belt which reflects inhomogeneity in crustal construction of

  2. 300 Area Treatability Test: Laboratory Development of Polyphosphate Remediation Technology for In Situ Treatment of Uranium Contamination in the Vadose Zone and Capillary Fringe

    Energy Technology Data Exchange (ETDEWEB)

    Wellman, Dawn M.; Pierce, Eric M.; Bacon, Diana H.; Oostrom, Martinus; Gunderson, Katie M.; Webb, Samuel M.; Bovaird, Chase C.; Cordova, Elsa A.; Clayton, Eric T.; Parker, Kent E.; Ermi, Ruby M.; Baum, Steven R.; Vermeul, Vincent R.; Fruchter, Jonathan S.

    2008-09-30

    This report presents results from bench-scale treatability studies conducted under site-specific conditions to optimize the polyphosphate amendment for implementation of a field-scale technology demonstration to stabilize uranium within the 300 Area vadose and smear zones of the Hanford Site. The general treatability testing approach consisted of conducting studies with site sediment and under site conditions, to develop an effective chemical formulation and infiltration approach for the polyphosphate amendment under site conditions. Laboratory-scale dynamic column tests were used to 1) quantify the retardation of polyphosphate and its degradation products as a function of water content, 2) determine the rate of polyphosphate degradation under unsaturated conditions, 3) develop an understanding of the mechanism of autunite formation via the reaction of solid phase calcite-bound uranium and aqueous polyphosphate remediation technology, 4) develop an understanding of the transformation mechanism, the identity of secondary phases, and the kinetics of the reaction between uranyl-carbonate and -silicate minerals with the polyphosphate remedy under solubility-limiting conditions, and 5) quantify the extent and rate of uranium released and immobilized based on the infiltration rate of the polyphosphate remedy and the effect of and periodic wet-dry cycling on the efficacy of polyphosphate remediation for uranium in the vadose zone and smear zone.

  3. Field application of innovative grouting agents for in situ stabilization of buried waste sites

    International Nuclear Information System (INIS)

    Loomis, G.G.; Farnsworth, R.K.

    1997-01-01

    This paper presents field applications for two innovative grouting agents that were used to in situ stabilize buried waste sites, via jet grouting. The two grouting agents include paraffin and a proprietary iron oxide based cement grout called TECT. These materials were tested in specially designed cold test pits that simulate buried transuranic waste at the Idaho National Engineering Laboratory (INEL). The field demonstrations were performed at the INEL in an area referred to as the Cold Test Pit, which is adjacent to the INEL Radioactive Waste Management Complex (RWMC). At the RWMC, 56,000 m 3 of transuranic (TRU) waste is co-mingled with over 170,000 m 3 of soil in shallow land burial. Improving the confinement of this waste is one of the options for final disposition of this waste. Using jet-grouting technology to inject these materials into the pore spaces of buried waste sites results in the creation of buried monolithic waste forms that simultaneously protect the waste from subsidence, while eliminating the migratory potential of hazardous and radioactive contaminants in the waste

  4. In situ stabilization of cadmium-, lead-, and zinc-contaminated soil using various amendments.

    Science.gov (United States)

    Lee, Sang-Hwan; Lee, Jin-Soo; Choi, Youn Jeong; Kim, Jeong-Gyu

    2009-11-01

    Chemical stabilization is an in situ remediation method that uses inexpensive amendments to reduce contaminant availability in polluted soil. We tested the effects of several amendments (limestone, red-mud, and furnace slag) on the extractability of heavy metals, microbial activities, phytoavailability of soil metals (assessed using lettuce, Lactuca sativa L.), and availability of heavy metals in ingested soil to the human gastrointestinal system (assessed using the physiologically based extraction test). The application of soil amendments significantly decreased the amount of soluble and extractable heavy metals in the soil (p<0.05). The decreased extractable metal content of soil was accompanied by increased microbial activity and decreased plant uptake of heavy metals. Soil microbial activities (soil respiration, urease, and dehydrogenase activity) significantly increased in limestone and red-mud-amended soils. Red-mud was the most effective treatment in decreasing heavy-metal concentrations in lettuce. Compared to non-amended control soil, lettuce uptake of Cd, Pb, and Zn was reduced 86%, 58%, and 73%, respectively, by the addition of red-mud.

  5. Nanocapsule of cationic liposomes obtained using "in situ" acrylic acid polymerization: stability, surface charge and biocompatibility.

    Science.gov (United States)

    Scarioti, Giovana Danieli; Lubambo, Adriana; Feitosa, Judith P A; Sierakowski, Maria Rita; Bresolin, Tania M B; de Freitas, Rilton Alves

    2011-10-15

    In this work, didecyldimethylammonium bromide (DDAB) and 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) (2.5:1) were used to prepare liposomes coated with polyacrylic acid (PAA) using "in situ" polymerization with 2.5, 5 and 25 mM of acrylic acid (AA). The PAA concentrations were chosen to achieve partially to fully covered capsules, and the polymerization reaction was observed with real-time monitoring using dynamic light scattering (NanoDLS). The DDAB:DOPE liposomes showed stability in the tested temperature range (25-70°C), whereas the results confirmed the success of the polymerization according to superficial charge (zeta potential of +66.7±1.2 mV) results and AFM images. For the liposomes that were fully coated with PAA (zeta potential of +0.3±3.9 mV), cytotoxicity was independent of the concentration of albumin. Cationic liposomes and nanocapsules of the stable liposomes coated with PAA were obtained by controlling the surface charge, which was the most important factor related to cytotoxicity. Thus, a potential, safe drug nanocarrier was successfully developed in this work. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Localized in situ polymerization on graphene surfaces for stabilized graphene dispersions.

    Science.gov (United States)

    Das, Sriya; Wajid, Ahmed S; Shelburne, John L; Liao, Yen-Chih; Green, Micah J

    2011-06-01

    We demonstrate a novel in situ polymerization technique to develop localized polymer coatings on the surface of dispersed pristine graphene sheets. Graphene sheets show great promise as strong, conductive fillers in polymer nanocomposites; however, difficulties in dispersion quality and interfacial strength between filler and matrix have been a persistent problem for graphene-based nanocomposites, particularly for pristine graphene. With this in mind, a physisorbed polymer layer is used to stabilize graphene sheets in solution. To create this protective layer, we formed an organic microenvironment around dispersed graphene sheets in surfactant solutions, and created a nylon 6, 10 or nylon 6, 6 coating via interfacial polymerization. Technique lies at the intersection of emulsion and admicellar polymerization; a similar technique was originally developed to protect luminescent properties of carbon nanotubes in solution. These coated graphene dispersions are aggregation-resistant and may be reversibly redispersed in water even after freeze-drying. The coated graphene holds promise for a number of applications, including multifunctional graphene-polymer nanocomposites. © 2011 American Chemical Society

  7. In situ vitrification demonstration for the stabilization of buried wastes at the Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Jacobs, G.K.; Spalding, B.P.; Carter, J.G.; Koegler, S.S.

    1987-01-01

    A demonstration of In Situ Vitrification (ISV) technology for the stabilization of radioactively contaminated soil sites at the Oak Ridge National Laboratory (ORNL) was successfully completed during July 1987. This demonstration is the first application of the ISV process not performed at the Hanford Site, where the technology was developed and patented by Pacific Northwest Laboratory (PNL). The joint ORNL-PNL pilot-scale demonstration was performed on a 3/8-scale trench (2 m deep x 1 m wide x 10 m long) that was constructed to simulate a typical seepage trench used for liquid low-level radioactive waste disposal at ORNL from 1951 to 1966. In the ISV process, electrodes are inserted around a volume of contaminated soil, power is applied to the electrodes, and the entire mass is melted from the surface of the soil down through the contaminated zone, thus making a glassy-to-microcrystalline waste form that incorporates the contaminants. Gases produced during the melting are collected, treated, monitored, and released through an off-gas process trailer. In the ORNL demonstration, a 25-t mass of melted rock approximately 1.2 m thick x 2.1 m wide x 4.9 m long was formed during 110 h of operation that consumed approximately 29 MWh of power. Data obtained on the operational performance of the test and waste-form durability will be used to assess the feasibility of applying the ISV technology to an actual waste trench

  8. Possibility of applying the gamma-gamma method to the in situ determination of uranium-ore densities

    International Nuclear Information System (INIS)

    Czubek, J.; Guitton, J.

    1965-01-01

    The principles of the gamma-gamma method are reviewed. It is shown in particular that, under certain conditions, the method makes it possible to obtain a representative measurement of the electronic density. Chemical analyses have been carried out on samples obtained from uranium deposits. The results show that an exact correlation exists between the massive and electronic densities. It is possible to consider the possibility of measuring the density of uranium-containing rocks by the gamma-gamma method. (authors) [fr

  9. Bicarbonate leaching of uranium

    International Nuclear Information System (INIS)

    Mason, C.

    1998-01-01

    The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented

  10. Bicarbonate leaching of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Mason, C.

    1998-12-31

    The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented.

  11. In-situ anatase phase stabilization of titania photocatalyst by sintering in presence of Zr{sup 4+} organic salts

    Energy Technology Data Exchange (ETDEWEB)

    Strini, Alberto, E-mail: alberto.strini@itc.cnr.it [Istituto per le Tecnologie della Costruzione (ITC-CNR), via Lombardia, 49, I-20098 San Giuliano Milanese (MI) (Italy); Sanson, Alessandra; Mercadelli, Elisa [Istituto di Scienza e Tecnologia dei Materiali Ceramici (ISTEC-CNR), via Granarolo, 64, I-48018 Faenza (RA) (Italy); Bendoni, Riccardo [Istituto di Scienza e Tecnologia dei Materiali Ceramici (ISTEC-CNR), via Granarolo, 64, I-48018 Faenza (RA) (Italy); Dipartimento di Scienze e Tecnologie Chimiche e Centro NAST - Università di Roma Tor Vergata, via della Ricerca Scientifica, I-00133 Roma (Italy); Marelli, Marcello; Dal Santo, Vladimiro [CNR–Istituto di Scienze e Tecnologie Molecolari, via Golgi, 19, I-20133 Milano (Italy); Schiavi, Luca [Istituto per le Tecnologie della Costruzione (ITC-CNR), via Lombardia, 49, I-20098 San Giuliano Milanese (MI) (Italy)

    2015-08-30

    Graphical abstract: - Highlights: • Existing commercial (P25) anatase was stabilized in-situ with Zr(IV) doping. • Highly active catalytic layers were obtained by screen-printing. • Increased thermal stability was demonstrated up to 200 °C without activity loss. • Enhanced activity was obtained because of the Zr(IV) doping. • Zirconium diffusion was assessed by STEM-EDS analysis. - Abstract: The direct in-situ stabilization of an anatase-based nanocrystalline photocatalyst (Degussa P25) was obtained by sintering the catalyst powder in presence of Zr{sup 4+} organic salts. This approach allows the doping of an already-formed nanocrystalline photocatalyst instead of introducing the dopant in the crystal lattice during the catalyst synthesis. The procedure was demonstrated by the production of thick ceramic layers using the screen printing technique. This new method allows to easily stabilize the anatase phase 200 °C higher than the undoped P25 maintaining the same photocatalytic activity. The process was studied using specifically formulated screen-printing inks added with Zr{sup 4+} organic salt at 1% and 2% Zr/Ti molar ratio. The anatase phase stability was investigated in the 500–900 °C temperature range analysing the resulting catalysts with XRD, TEM and (S)TEM-EDS. The catalytic activity of the screen-printed layers was assessed by measuring the degradation of toluene in air at ambient concentration (500 nmol m{sup −3}) and low UV-A irradiance (180 μW cm{sup −2}). The described in-situ stabilization method could be potentially applied to any deposition process involving already formed anatase photocatalyst, allowing higher sintering temperature and then an improved mechanical stability of the active layers without photocatalytic activity degradation.

  12. In-situ anatase phase stabilization of titania photocatalyst by sintering in presence of Zr4+ organic salts

    International Nuclear Information System (INIS)

    Strini, Alberto; Sanson, Alessandra; Mercadelli, Elisa; Bendoni, Riccardo; Marelli, Marcello; Dal Santo, Vladimiro; Schiavi, Luca

    2015-01-01

    Graphical abstract: - Highlights: • Existing commercial (P25) anatase was stabilized in-situ with Zr(IV) doping. • Highly active catalytic layers were obtained by screen-printing. • Increased thermal stability was demonstrated up to 200 °C without activity loss. • Enhanced activity was obtained because of the Zr(IV) doping. • Zirconium diffusion was assessed by STEM-EDS analysis. - Abstract: The direct in-situ stabilization of an anatase-based nanocrystalline photocatalyst (Degussa P25) was obtained by sintering the catalyst powder in presence of Zr 4+ organic salts. This approach allows the doping of an already-formed nanocrystalline photocatalyst instead of introducing the dopant in the crystal lattice during the catalyst synthesis. The procedure was demonstrated by the production of thick ceramic layers using the screen printing technique. This new method allows to easily stabilize the anatase phase 200 °C higher than the undoped P25 maintaining the same photocatalytic activity. The process was studied using specifically formulated screen-printing inks added with Zr 4+ organic salt at 1% and 2% Zr/Ti molar ratio. The anatase phase stability was investigated in the 500–900 °C temperature range analysing the resulting catalysts with XRD, TEM and (S)TEM-EDS. The catalytic activity of the screen-printed layers was assessed by measuring the degradation of toluene in air at ambient concentration (500 nmol m −3 ) and low UV-A irradiance (180 μW cm −2 ). The described in-situ stabilization method could be potentially applied to any deposition process involving already formed anatase photocatalyst, allowing higher sintering temperature and then an improved mechanical stability of the active layers without photocatalytic activity degradation

  13. Working and benefit project by the in-situ leaching of the copper-uranium ore of the deposit named Luz del Cobre, in the municipality of Soyopa, state of Sonora, Mexico

    International Nuclear Information System (INIS)

    Parga P, J.de J.

    1976-01-01

    This research was carried out with the object to recover the existing uranium in the copper-uranium deposit of Luz del Cobre located at 1300 Kms. approximately of the NW of Mexico City in the state of Sonora this deposit is geologically formed by a partially mineralized chimney which contains 572,732 tons of uranium ore with an average of 362.26g. of U 3 O 8 per ton, which represents 207,374 tons of U 3 O 8 in situ. To recover the uranium from this deposit, the only technical and economical possibility which presents a real interest is the system of leaching in situ. This operation will consist in the selective dissolution of the copper and uranium through leaching solution with a pH varying from 2.2 to 2.5, leaving the gangue on the ground and collecting the enriched solutions at the lower level of the mine, precipitating the copper subsequently through scrap iron and recovering the uranium from the tails of the copper precipitation plant through an ionic interchange process in counter current and its subsequent elution solvent extraction, reextraction and precipitation. This system makes possible to recover an uranium concentrate up to 98% of U 3 O 8 and practically free from impurities. The production cost would cost exceeding $300.00 Mexican currency per Kg of U 3 O 8 . (author)

  14. Use of Sodium Dithionite as Part of a More Efficient Groundwater Restoration Method Following In-situ Recovery of Uranium at the Smith-Ranch Highland Site in Wyoming

    Science.gov (United States)

    Harris, R.; Reimus, P. W.; Ware, D.; Williams, K.; Chu, D.; Perkins, G.; Migdissov, A. A.; Bonwell, C.

    2017-12-01

    Uranium is primarily mined for nuclear power production using an aqueous extraction technique called in-situ recovery (ISR). ISR can pollute groundwater with residual uranium and other heavy metals. Reverse osmosis and groundwater sweep are currently used to restore groundwater after ISR mining, but are not permanent solutions. Sodium dithionite is being tested as part of a method to more permanently restore groundwater after ISR mining at the Smith-Ranch Highland site in Wyoming. Sodium dithionite is a chemical reductant that can reduce sediments that were oxidized during ISR. The reduced sediments can reduce soluble uranium (VI) in the groundwater to insoluble uranium (IV). Laboratory studies that use sodium dithionite to treat sediments and waters from the site may help predict how it will behave during a field deployment. An aqueous batch experiment showed that sodium dithionite reduced uranium in post-mined untreated groundwater from 38 ppm to less than 1 ppm after 1 day. A sediment reduction batch experiment showed that sodium dithionite-treated sediments were capable of reducing uranium in post-mined untreated groundwater from 38 ppm to 2 ppm after 7 days. One column experiment is showing post-mined sodium dithionite-treated sediments are capable of reducing uranium in post-mined groundwater for over 30 pore volumes past the initial injection. While these results are promising for field deployments of sodium dithionite, another column experiment with sodium dithionite-treated sediments containing uranium rich organic matter is showing net production of uranium instead of uranium uptake. Sodium dithionite appears to liberate uranium from the organic matter. Another sediment reduction experiment is being conducted to further investigate this hypothesis. These experiments are helping guide plans for field deployments of sodium dithionite at uranium ISR mining sites.

  15. Revegetation and rock cover for stabilization of inactive uranium mill tailings disposal sites. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Beedlow, P.A.

    1984-05-01

    Guidelines for using vegetation and rock to protect inactive uranium mill tailings from erosion were developed by Pacific Northwest Laboratory as part of the Department of Energy's Uranium Mill Tailings Remedial Action Project (UMTRAP) Technology Development program. Information on soils, climate, and vegetation were collected for 20 inactive tailings sites in the western United States. Sites were grouped according to similarities in climate and vegetation. Soil loss for those sites was characterized using the Universal Soil Loss Equation. Test plots were used to evaluate (1) the interaction between vegetation and sealant barrier systems and (2) the effects of surface rock on soil water and vegetation. Lysimeter and simulation studies were used to direct and support field experiments. 49 references, 17 figures, 16 tables.

  16. Revegetation and rock cover for stabilization of inactive uranium mill tailings disposal sites. Final report

    International Nuclear Information System (INIS)

    Beedlow, P.A.

    1984-05-01

    Guidelines for using vegetation and rock to protect inactive uranium mill tailings from erosion were developed by Pacific Northwest Laboratory as part of the Department of Energy's Uranium Mill Tailings Remedial Action Project (UMTRAP) Technology Development program. Information on soils, climate, and vegetation were collected for 20 inactive tailings sites in the western United States. Sites were grouped according to similarities in climate and vegetation. Soil loss for those sites was characterized using the Universal Soil Loss Equation. Test plots were used to evaluate (1) the interaction between vegetation and sealant barrier systems and (2) the effects of surface rock on soil water and vegetation. Lysimeter and simulation studies were used to direct and support field experiments. 49 references, 17 figures, 16 tables

  17. Characterization and thermal stability of uranium peroxides by thermogravimetry and differential scanning calorimetry

    International Nuclear Information System (INIS)

    Souza Junior, P.T. de; Abrao, A.

    1982-01-01

    The characterization and thermal behaviour of uranium peroxide samples prepared by precipitation with hydrogen peroxide from uranyl nitrate solution is described. The latter was obtained by dissolution of ammonium diuranate and ammonium uranyl tricarbonate. TG and DTG curves were recorded in the temperature range from room temperature to 700 0 C. DSC curves were recorded from room temperature to 600 0 C. The heating rate was 5 0 C/min. Based upon the DTG curves of a great number of samples, the uranium peroxides were classified in five groups. The collected information was used to recognise the temperature at which the peroxide decomposes and to know its sequential conversion to UO 3 and U 3 O 8 , the evolution of molecules of water of crystallization and absorption, and the elimination of occluded nitrate ions. The results allowed to conclude that no NH + 4 nor H 2 O 2 molecules were occluded by uranium peroxide. The stoichiometric composition of representative samples for the five groups is indicated. (Author) [pt

  18. Environmental factors affecting long-term stabilization of radon suppression covers for uranium mill tailings

    International Nuclear Information System (INIS)

    Young, J.K.; Long, L.W.; Reis, J.W.

    1982-04-01

    Pacific Northwest Laboratory is investigating the use of a rock armoring blanket (riprap) to mitigate wind and water erosion of an earthen radon suppression cover applied to uranium mill tailings. To help determine design stresses for the tailings piles, environmental parameters are characterized for the five active uranium-producing regions on a site-specific basis. Only conventional uranium mills that are currently operating or that are scheduled to open in the mid 1980s are considered. Available data indicate that flooding has the most potential for disrupting a tailings pile. The arid regions of the Wyoming Basins and the Colorado Plateau are subject to brief storms of high intensity. The Texas Gulf Coast has the highest potential for extreme precipitation from hurricane-related storms. Wind data indicate average wind speeds from 3 to 6 m/sec for the sites, but extremes of 40 m/sec can be expected. Tornado risks range from low to moderate. The Colorado Plateau has the highest seismic potential, with maximum acceleration caused by earthquakes ranging from 0.2 to 0.4 g. Any direct effect from volcanic eruption is negligible, as all mills are located 90 km or more from an igneous or hydrothermal system

  19. Study of uranium +4 stabilization by the formation of a complex with a heteropolyanion ligand, for its off-lines analysis

    International Nuclear Information System (INIS)

    Bion, L.

    1995-01-01

    The study of the behaviour of uranium in oxidation state +4, during uranium/plutonium separation step of the PUREX process for reprocessing nuclear fuels, requires the availability of an efficient analytical method allowing the stabilization and off-line analysis of sample of aqueous and organic solutions containing this reagent. It was accordingly decided to develop a stabilization method using the heteropolyanion P 2 W 17 O 61 10- (PWO ' ) as a selective ligand. Besides the stabilization effect, the complexation of uranium +4 results in the appearance of an intense and specific band on the visible absorption spectrum of the formed U(PWO) 2 16- complex. This property made it possible to consider the sensitive spectrophotometric analysis of the sample. The work presented first helped to determine, in the presence of PWO, the characteristic thermodynamic data of the reaction involving uranium +4 and +6, plutonium +3 and +4, nitrous and nitric acids, and hydrazine. In the light of these results, it was possible to plan the development of the stabilisation method. The use of PWO thus helped (1) to design a method capable of stopping any reaction involving the uranium +4 / uranium +6 pair, and (2) to perform the simple analysis of uranium +4. The study presented in the second part uses the example of the U 4+ cation to understand the reasons for the selectivity of the complexation of actinides +4 by PWO. Owing to the remarkable spectroscopic and magnetic properties of this cation, ti was possible to acquire data concerning the structure of the U(PWO) 2 16- complex, both in solution and in the solid state. It was thus demonstrated that the geometry of the environment of U 4+ (eight oxygen forming a cubic anti-prism), which is perfectly complementary to that of the 5f electron wave functions of the actinide, helps to explain the selectivity of the complexation of actinides +4. (author). refs., 46 figs., 40 tabs

  20. Experimental Plan: 300 Area Treatability Test: In Situ Treatment of the Vadose Zone and Smear Zone Uranium Contamination by Polyphosphate Infiltration

    International Nuclear Information System (INIS)

    Wellman, Dawn M.; Pierce, Eric M.; Oostrom, Mart; Fruchter, Jonathan S.

    2007-01-01

    The overall objectives of the treatability test is to evaluate and optimize polyphosphate remediation technology for infiltration either from ground surface, or some depth of excavation, providing direct stabilization of uranium within the deep vadose and capillary fringe above the 300 Area aquifer. Expected result from this experimental plan is a data package that includes: (1) quantification of the retardation of polyphosphate, (2) the rate of degradation and the retardation of degradation products as a function of water content, (3) an understanding of the mechanism of autunite formation via the reaction of solid phase calcite-bound uranium and aqueous polyphosphate remediation technology, (4) an understanding of the transformation mechanism, identity of secondary phases, and the kinetics of the reaction between uranyl-carbonate and silicate minerals with the polyphosphate remedy under solubility-limiting conditions, (5) quantification of the extent and rate of uranium released and immobilized based on the infiltration rate of the polyphosphate remedy and the effect of and periodic wet-dry cycling on the efficacy of polyphosphate remediation for uranium in the vadose zone and capillary fringe, and (6) quantification of reliable equilibrium solubility values for autunite under hydraulically unsaturated conditions allowing accurate prediction of the long-term stability of autunite. Moreover, results of intermediate scale testing will quantify the transport of polyphosphate and degradation products, and yield degradation rates, at a scale that is bridging the gap between the small-scale UFA studies and the field scale. These results will be used to test and verify a site-specific, variable saturation, reactive transport model and to aid in the design of a pilot-scale field test of this technology. In particular, the infiltration approach and monitoring strategy of the pilot test would be primarily based on results from intermediate-scale testing. Results from this

  1. In situ solidification/stabilization pilot study for the treatment of coal tar contaminated soils and river sediments

    International Nuclear Information System (INIS)

    Lawson, M.A.; Venn, J.G.; Pugh, L.B.; Vallis, T.

    1996-01-01

    Coal tar contamination was encountered at a former coal gasification site in soils below the groundwater table, and in the sediments of the adjacent river. Ex situ remediation techniques at this site would be costly because of the need to dewater the impacted media. In situ solidification/stabilization was tested to evaluate its effectiveness. Treatability testing was performed to evaluate a Portland cement/fly ash binder system with added stabilizing agents. Results were sufficiently promising to warrant pilot testing. Grout containing Portland cement, fly ash, organically modified clay, and granular activated carbon was pilot tested at the site. Test specimens were collected and tested to evaluate durability, compressive strength, and permeability. The samples were extracted by several methods and analyzed to measure the leachable concentrations of organic compounds and metals. Results indicated acceptable physical characteristics. Leachable concentrations of most polynuclear aromatic compounds were decreased

  2. Influence of heterogeneous ammonium availability on bacterial community structure and the expression of nitrogen fixation and ammonium transporter genes during in situ bioremediation of uranium-contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Mouser, P.J.; N' Guessan, A.L.; Elifantz, H.; Holmes, D.E.; Williams, K.H.; Wilkins, M.J.; Long, P.E.; Lovley, D.R.

    2009-04-01

    The impact of ammonium availability on microbial community structure and the physiological status and activity of Geobacter species during in situ bioremediation of uranium-contaminated groundwater was evaluated. Ammonium concentrations varied by as much as two orders of magnitude (<4 to 400 {micro}M) across the study site. Analysis of 16S rRNA gene sequences suggested that ammonium influenced the composition of the microbial community prior to acetate addition with Rhodoferax species predominating over Geobacter species at the site with the highest ammonium, and Dechloromonas species dominating at sites with lowest ammonium. However, once acetate was added, and dissimilatory metal reduction was stimulated, Geobacter species became the predominant organisms at all locations. Rates of U(VI) reduction appeared to be more related to the concentration of acetate that was delivered to each location rather than the amount of ammonium available in the groundwater. In situ mRNA transcript abundance of the nitrogen fixation gene, nifD, and the ammonium importer gene, amtB, in Geobacter species indicated that ammonium was the primary source of nitrogen during in situ uranium reduction, and that the abundance of amtB transcripts was inversely correlated to ammonium levels across all sites examined. These results suggest that nifD and amtB expression by subsurface Geobacter species are closely regulated in response to ammonium availability to ensure an adequate supply of nitrogen while conserving cell resources. Thus, quantifying nifD and amtB expression appears to be a useful approach for monitoring the nitrogen-related physiological status of Geobacter species in subsurface environments during bioremediation. This study also emphasizes the need for more detailed analysis of geochemical/physiological interactions at the field scale, in order to adequately model subsurface microbial processes.

  3. In-situ anatase phase stabilization of titania photocatalyst by sintering in presence of Zr4+ organic salts

    Science.gov (United States)

    Strini, Alberto; Sanson, Alessandra; Mercadelli, Elisa; Bendoni, Riccardo; Marelli, Marcello; Dal Santo, Vladimiro; Schiavi, Luca

    2015-08-01

    The direct in-situ stabilization of an anatase-based nanocrystalline photocatalyst (Degussa P25) was obtained by sintering the catalyst powder in presence of Zr4+ organic salts. This approach allows the doping of an already-formed nanocrystalline photocatalyst instead of introducing the dopant in the crystal lattice during the catalyst synthesis. The procedure was demonstrated by the production of thick ceramic layers using the screen printing technique. This new method allows to easily stabilize the anatase phase 200 °C higher than the undoped P25 maintaining the same photocatalytic activity. The process was studied using specifically formulated screen-printing inks added with Zr4+ organic salt at 1% and 2% Zr/Ti molar ratio. The anatase phase stability was investigated in the 500-900 °C temperature range analysing the resulting catalysts with XRD, TEM and (S)TEM-EDS. The catalytic activity of the screen-printed layers was assessed by measuring the degradation of toluene in air at ambient concentration (500 nmol m-3) and low UV-A irradiance (180 μW cm-2). The described in-situ stabilization method could be potentially applied to any deposition process involving already formed anatase photocatalyst, allowing higher sintering temperature and then an improved mechanical stability of the active layers without photocatalytic activity degradation.

  4. Remedial Action Plan and site conceptual design for stabilization of the inactive uranium mill tailings site at Spook, Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, M L [USDOE Albuquerque Operations Office, NM (United States). Uranium Mill Tailings Remedial Action Project Office; Sullivan, M [Wyoming State Government, Cheyenne, WY (United States)

    1990-04-01

    This Remedial Action Plan (RAP) has been developed to serve a threefold purpose. It presents the series of activities which are proposed by the US Department of Energy (DOE) to accomplish long-term stabilization and control of radioactive materials at an inactive uranium processing site northeast of Casper, Wyoming, and referred to as the Spook site. It provides a characterization of the present conditions at the site and also serves to document the concurrence of the State of Wyoming and the US Nuclear Regulatory Commission (NRC) in the remedial action. This agreement, upon execution by the DOE and the State of Wyoming, and concurrence by the NRC, becomes Appendix B of the Cooperative Agreement.

  5. Remedial Action Plan and site conceptual design for stabilization of the inactive uranium mill tailings site at Spook, Wyoming

    International Nuclear Information System (INIS)

    Matthews, M.L.

    1990-04-01

    This Remedial Action Plan (RAP) has been developed to serve a threefold purpose. It presents the series of activities which are proposed by the US Department of Energy (DOE) to accomplish long-term stabilization and control of radioactive materials at an inactive uranium processing site northeast of Casper, Wyoming, and referred to as the Spook site. It provides a characterization of the present conditions at the site and also serves to document the concurrence of the State of Wyoming and the US Nuclear Regulatory Commission (NRC) in the remedial action. This agreement, upon execution by the DOE and the State of Wyoming, and concurrence by the NRC, becomes Appendix B of the Cooperative Agreement

  6. Construction of Eh-pH and other stability diagrams of uranium in a multicomponent system with a microcomputer

    International Nuclear Information System (INIS)

    Haung, H.; Cuentas, L.

    1989-01-01

    Stability diagrams for a multicomponent system in aqueous chemistry provide important information for hydrometallurgy, corrosion science, geochemistry and environmental science. Two distinct types of diagrams constructed are predominance diagrams and distribution diagrams. The ability to construct stability diagrams easily, quickly and accurately is most helpful in research and development and in academic programs. The use of a microcomputer is handicapped by slow speed and limited memory. Developing program methods that promote easy calculation and plot the diagram directly on a CRT or a plotter is a primary concern. As presented in this paper, the calculation of equilibrium and boundary constraints, combined with isolation of stability areas, works well for constructing predominance diagrams. Equilibrium constraints can be obtained based on free energies of formation. Boundary constraints for the ligand component are the boundary of the diagram, and constraints for the main component are the surrounding lines of each dominant ligand. Other considerations regarding the chemical model, mathematics computation and the use of microcomputers pertaining to diagram construction are discussed. The uranium in a multicomponent system is used for demonstration

  7. The role of capital realignment versus in situ stabilization for the treatment of slipped capital femoral epiphysis.

    Science.gov (United States)

    Souder, Christopher D; Bomar, James D; Wenger, Dennis R

    2014-12-01

    Slipped capital femoral epiphysis (SCFE) can be treated by a variety of methods with the traditional method of in situ pin fixation being most commonly used. More recently, the Modified Dunn (Mod. Dunn) procedure consisting of capital realignment has been popularized as a treatment method for SCFE, particularly for more severe cases. Over the last 5 years, our institution has selectively used this method for more complex cases. The purpose of this article is to evaluate the differences between these 2 treatment methods in terms of avascular necrosis (AVN) rate, reoperation rate, and complication rate. Eighty-eight hips that were surgically treated for SCFE between July 2004 and June 2012 met our inclusion criteria. The in situ fixation group included 71 hips, whereas 17 hips were anatomically reduced with the Mod. Dunn procedure. Loder classification, severity, acuity, complication rate, and reoperation rate were determined for the 2 cohorts. The χ analysis was performed to evaluate the relationship between the treatment method and outcome. As expected, stable slips did well with in situ pinning with no cases of AVN, even in more severe slips. Ten stable slips were treated with the Mod. Dunn approach and 2 (20%) developed AVN. Unstable slips were more difficult to treat with 3 of the 7 hips stabilized in situ developing AVN (43%). Two of the 7 unstable slips treated by the Mod. Dunn procedure developed AVN (29%). The other outcomes studied (reoperation rate and complication rate) were not significantly related to the surgical treatment method (P = 0.732 and 0.261, respectively). In situ pinning remains a safe and predictable method for treatment of stable SCFE with no AVN noted, even in severe slips. Attempts to anatomically reduce stable slips led to severe AVN in 20% of cases, thus this treatment approach should be considered with caution. Treatment of unstable slips remains problematic with high AVN rates noted whether treated by in situ fixation or capital

  8. Evaluating the Long-Term Stability of Metals Precipitated In-Situ

    Science.gov (United States)

    Because metals (including metals and metalloids) cannot be destroyed, unlike organic contaminants, in-situ approaches for their removal from groundwater necessarily involves fixation/immobilization in the solid aquifer matrix. Consequently, the success of precipitation based in...

  9. Evidence for the long-term stability of uranium mill tailings: survivability of ancient man-made earthern structures

    International Nuclear Information System (INIS)

    Lindsey, C.G.; Mishima, J.

    1982-09-01

    Pacific Northwest Laboratory (PNL), as part of a study for the Nuclear Regulatory Commission (NRC), is investigating long-term stabilization techniques for uranium mill tailings piles. Part of this invetigation involves the design of a rock armoring blanket to mitigate wind and water erosion of the underlying soil cover, which, in turn, prevents exposure of the tailings to the environment. However, the need for the armoring blanket, as well as this blanket's effectiveness, depends on the stability of the underlying soil cap (radon suppression cover) and on the tailings themselves. Compelling evidence in archaeological records suggests that large man-made earthen structures can remain sound and intact for time periods comparable to those required for the tailings piles. In this paper we present archaeological evidence of the existence and survivability of man-made earthen and rock structures through specific examples of such structures around the world. We also review factors contributing to the survival or destruction of these structures. Archaeological evidence suggests that whereas natural erosional forces have affected these structures, man's activities (e.g., agriculture, looting) have been the most damaging. The influence of climate, building materials, and construction techniques on survivability is addressed in this paper

  10. Geochemical barriers formed during in-situ leaching in ore-bearing horizons of hydrogenic uranium deposit

    International Nuclear Information System (INIS)

    Solodov, E.N.

    1994-01-01

    The behaviour of major metallogenetic element and associated elements on the boundary of the leaching solution transiting to the unchanged natural water in a layered uranium deposit of infiltration origin is studied. Neutralization geochemical barrier and their relevant secondary barriers-degassing barrier and neutralization barrier are defined, and recent accumulation of uranium, rare earth elements and a series of other elements at these barriers are in progress. The action of underground microorganism during this process is pointed out; the neutralization capacity of the ore-hosting terrigenous rocks is determined and the dimension of the matter removal, migration and reprecipitation in the studied system is evaluated. The principal conclusion is that the studied geological media have sufficient protective nature to resist direct and strong leaching action of the solution

  11. Uranium: one utility's outlook

    International Nuclear Information System (INIS)

    Gass, C.B.

    1983-01-01

    The perspective of the Arizona Public Service Company (APS) on the uncertainty of uranium as a fuel supply is discussed. After summarizing the history of nuclear power and the uranium industries, a projection is made for the future uranium market. An uncrtain uranium market is attributed to various determining factors that include international politics, production costs, non-commercial government regulation, production-company stability, and questionable levels of uranium sales. APS offers its solutions regarding type of contract, choice of uranium producers, pricing mechanisms, and aids to the industry as a whole. 5 references, 10 figures, 1 table

  12. Analogue studies in the alligator rivers region. In-situ measurement of uranium series nuclides with SHRIMP

    Energy Technology Data Exchange (ETDEWEB)

    Nagano, Tetsushi; Yanase, Nobuyuki; Ohnuki, Toshihiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Sato, Tsutomu; Isobe, Hiroshi; Williams, I.S.; Zaw, M.; Payne, T.E.; Airey, P.L.

    1999-03-01

    The SHRIMP analyses have been conducted for rock samples from the Koongarra secondary ore deposit to obtain activity ratios of {sup 234}U/{sup 238}U and isotopic ratios of {sup 207}Pb/{sup 206}Pb and {sup 204}Pb/{sup 206}Pb. Target minerals for the analyses were iron minerals and kaolinite, which are the main weathering products in this area. The activity ratios of {sup 234}U/{sup 238}U were obtained based on counts at masses of uranium metal. The {sup 234}U/{sup 238}U activity ratios based on counts of uranium oxides were not appropriate, because count rates of {sup 234}U{sup 16}O were interfered by those of {sup 238}U{sup 12}C molecule. The activity ratios of {sup 234}U/{sup 238}U were approximately unity for crystalline iron nodules. This fact suggested that the mean residence time of uranium within the iron nodules was at least 1 million years. On the other hand, slightly higher values than unity were obtained for kaolinite. Lead isotopes were investigated and a positive relationship was recognized between {sup 207}Pb/{sup 206}Pb and {sup 204}Pb/{sup 206}Pb isotope ratios. (author)

  13. The effect of low-temperature aging on the microstructure and deformation of uranium- 6 wt% niobium: An in-situ neutron diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D.W., E-mail: dbrown@lanl.gov [Material Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545 (United States); Bourke, M.A.M. [Material Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545 (United States); Clarke, A.J. [Department of Metallurgical and Materials Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO, 80401 (United States); Field, R.D.; Hackenberg, R.E.; Hults, W.L. [Material Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545 (United States); Thoma, D.J. [Department of Materials Science and Engineering, University of Wisconsin Madison, Madison, WI, 3706 (United States)

    2016-12-01

    The mechanical properties of uranium-niobium alloys evolve with aging at relatively low temperatures due to subtle microstructural changes. In-situ neutron diffraction measurements during aging of a monoclinic U-6Nb alloy at temperatures to 573 K were performed to monitor these changes. Further, in-situ neutron diffraction studies during deformation of U-6Nb in the as-quenched state and after aging for two and eight hours at 473 K were completed to assess the influence of microstructural evolution on mechanical properties. With heating, large anisotropic changes in lattice parameter were observed followed by relaxation with time at the aging temperature. The lattice parameters return to nearly their initial values with cooling. The active plastic deformation mechanisms including, in order of occurrence, shape-memory de-twinning, mechanical twinning, and slip-mediated deformation do not change with prior aging. However, the resistance to motion of the as-quenched martensitic twin boundaries increases following aging, resulting in the observed increase in initial yield strength.

  14. IN-SITU RADIONUCLIDE TRANSPORT NEAR THE NOPAL I URANIUM DEPOSIT AT PENA BLANCA, MEXICO: CONSTRAINTS FROM SHORT-LIVED DECAY-SERIES RADIONUCLIDES

    International Nuclear Information System (INIS)

    Luo, S.; Ku, T.L.; Todd, V.; Murrell, M.; Pineda, J. Alfredo Rodriguez; Dinsmoor, J.; Mitchell, A.

    2005-01-01

    For nuclear waste management, an important mechanism by which radioactive waste components are isolated from returning to the human environment, the biosphere, is by the geological barrier in which the effectiveness of the barrier is characterized by in-situ retardation factor, i.e., the transport rate of a radionuclide relative to that of groundwater. As part of natural analog studies of the Yucca Mountain Project of the U. S. Department of Energy, we propose such characterization by using naturally-occurring decay-series radioisotopes as an analog. We collected large-volume (>1000 liters) groundwater samples from three wells (PB, Pozos, and PB4, respectively) near the Nopal I Uranium Ore site at Pena Blanca, Mexico, by using an in-situ Mn-cartridge filtration technique for analysis of short-lived decay-series radionuclides. Results show that the activities of short-lived radioisotopes ( 228 Ra, 224 Ra and 223 Ra) and activity ratios of 224 Ra/ 228 Ra and 224 Ra/ 223 Ra are higher at PB and Pozos than at PB4. In contrast, the 210 Po activity is much lower at PB and Pozos than at PB4. The high Ra activities and activities ratios at PB and Pozos are attributable to the high alpha-recoil input from the aquifer rocks, while the high 210 Po activity at PB4 is due to the enhanced colloidal transport. Based on a uranium-series transport model, we estimate that the in-situ retardation factor of Ra is (0.43 ± 0.02) x 10 3 at PB, (1.68 ± 0.08) x 10 3 at Pozos, and (1.19 ± 0.08) x 10 3 at PB4 and that the mean fracture width in the aquifer rocks is about 0.23 (micro)m at PB, 0.37 (micro)m at Posos, and 4.0 (micro)m at PB4, respectively. The large fracture width at PB4 as derived from the model provides an additional evidence to the inference from the Po measurements that particle-reactive radionuclides are transported mainly as colloidal forms through the large fractures in rocks. Our model also suggests that in addition to alpha recoil, decay of 226 Ra from the adsorbed

  15. IN-SITU RADIONUCLIDE TRANSPORT NEAR THE NOPAL I URANIUM DEPOSIT AT PENA BLANCA, MEXICO: CONSTRAINTS FROM SHORT-LIVED DECAY-SERIES RADIONUCLIDES

    Energy Technology Data Exchange (ETDEWEB)

    S. Luo; T.L. Ku; V. Todd; M. Murrell; J. Alfredo Rodriguez Pineda; J. Dinsmoor; A. Mitchell

    2005-07-11

    For nuclear waste management, an important mechanism by which radioactive waste components are isolated from returning to the human environment, the biosphere, is by the geological barrier in which the effectiveness of the barrier is characterized by in-situ retardation factor, i.e., the transport rate of a radionuclide relative to that of groundwater. As part of natural analog studies of the Yucca Mountain Project of the U. S. Department of Energy, we propose such characterization by using naturally-occurring decay-series radioisotopes as an analog. We collected large-volume (>1000 liters) groundwater samples from three wells (PB, Pozos, and PB4, respectively) near the Nopal I Uranium Ore site at Pena Blanca, Mexico, by using an in-situ Mn-cartridge filtration technique for analysis of short-lived decay-series radionuclides. Results show that the activities of short-lived radioisotopes ({sup 228}Ra, {sup 224}Ra and {sup 223}Ra) and activity ratios of {sup 224}Ra/{sup 228}Ra and {sup 224}Ra/{sup 223}Ra are higher at PB and Pozos than at PB4. In contrast, the {sup 210}Po activity is much lower at PB and Pozos than at PB4. The high Ra activities and activities ratios at PB and Pozos are attributable to the high alpha-recoil input from the aquifer rocks, while the high {sup 210}Po activity at PB4 is due to the enhanced colloidal transport. Based on a uranium-series transport model, we estimate that the in-situ retardation factor of Ra is (0.43 {+-} 0.02) x 10{sup 3} at PB, (1.68 {+-} 0.08) x 10{sup 3} at Pozos, and (1.19 {+-} 0.08) x 10{sup 3} at PB4 and that the mean fracture width in the aquifer rocks is about 0.23 {micro}m at PB, 0.37 {micro}m at Posos, and 4.0 {micro}m at PB4, respectively. The large fracture width at PB4 as derived from the model provides an additional evidence to the inference from the Po measurements that particle-reactive radionuclides are transported mainly as colloidal forms through the large fractures in rocks. Our model also suggests that

  16. In Situ Immobilization of Uranium in Structured Porous Media via Biomineralization at the Fracture/Matrix Interface - Subproject to Co-PI Eric E. Roden. Final report

    International Nuclear Information System (INIS)

    Roden, Eric E.

    2007-01-01

    Although the biogeochemical processes underlying in situ bioremediation technologies are increasingly well understood, field-scale heterogeneity (both physical and biogeochemical) remains a major obstacle to successful field-scale implementation. In particular, slow release of contamination from low-permeability regions (primarily by diffusive/dispersive mass transfer) can hinder the effectiveness of remediation. The research described in this report was conducted in conjunction with a project entitled ''In Situ Immobilization of Uranium in Structured Porous Media via Biomineralization at the Fracture/Matrix Interface'', which was funded through the Field Research element of the former NABIR Program (now the Environmental Remediation Sciences Program) within the Office of Biological and Environmental Research. Dr. Timothy Scheibe (Pacific Northwest National Laboratory) was the overall PI/PD for the project, which included Scott Brooks (Oak Ridge National Laboratory) and Eric Roden (formerly at The University of Alabama, now at the University of Wisconsin) as separately-funded co-PIs. The overall goal of the project was to evaluate strategies that target bioremediation at interfaces between high- and low-permeability regions of an aquifer in order to minimize the rate of contaminant transfer into high-permeability/high fluid flow zones. The research was conducted at the Area 2 site of the Field Research Center (FRC) at Oak Ridge National Laboratory (ORNL). Area 2 is a shallow pathway for migration of contaminated groundwater to seeps in the upper reach of Bear Creek at ORNL, mainly through a ca. 1 m thick layer of gravel located 4-5 m below the ground surface. Hydrological tracer studies indicate that the gravel layer receives input of uranium from both upstream sources and from diffusive mass transfer out of highly contaminated fill and saprolite materials above and below the gravel layer. We sought to test the hypothesis that injection of electron donor into this

  17. In Situ Immobilization of Uranium in Structured Porous Media via Biomineralization at the Fracture/Matrix Interface – Subproject to Co-PI Eric E. Roden

    Energy Technology Data Exchange (ETDEWEB)

    Eric E. Roden

    2007-11-02

    Although the biogeochemical processes underlying in situ bioremediation technologies are increasingly well understood, field-scale heterogeneity (both physical and biogeochemical) remains a major obstacle to successful field-scale implementation. In particular, slow release of contamination from low-permeability regions (primarily by diffusive/dispersive mass transfer) can hinder the effectiveness of remediation. The research described in this report was conducted in conjunction with a project entitled “In Situ Immobilization of Uranium in Structured Porous Media via Biomineralization at the Fracture/Matrix Interface”, which was funded through the Field Research element of the former NABIR Program (now the Environmental Remediation Sciences Program) within the Office of Biological and Environmental Research. Dr. Timothy Scheibe (Pacific Northwest National Laboratory) was the overall PI/PD for the project, which included Scott Brooks (Oak Ridge National Laboratory) and Eric Roden (formerly at The University of Alabama, now at the University of Wisconsin) as separately-funded co-PIs. The overall goal of the project was to evaluate strategies that target bioremediation at interfaces between high- and low-permeability regions of an aquifer in order to minimize the rate of contaminant transfer into high-permeability/high fluid flow zones. The research was conducted at the Area 2 site of the Field Research Center (FRC) at Oak Ridge National Laboratory (ORNL). Area 2 is a shallow pathway for migration of contaminated groundwater to seeps in the upper reach of Bear Creek at ORNL, mainly through a ca. 1 m thick layer of gravel located 4-5 m below the ground surface. Hydrological tracer studies indicate that the gravel layer receives input of uranium from both upstream sources and from diffusive mass transfer out of highly contaminated fill and saprolite materials above and below the gravel layer. We sought to test the hypothesis that injection of electron donor into

  18. In situ preparation of CuS cathode with unique stability and high rate performance for lithium ion batteries

    International Nuclear Information System (INIS)

    Wang Yourong; Zhang Xianwang; Chen Peng; Liao Hantao; Cheng Siqing

    2012-01-01

    A simple approach, for the first time, was presented for in situ preparation of the CuS cathode. The obtained CuS cathodes were investigated by the measurements of X-ray diffraction pattern, scanning electronic microscopy, and electrochemical performance. The results indicate the CuS cathodes are composed of plenty of nano flakes, which construct a large 3-D net structure. Moreover, the CuS cathodes exhibit reversible capacity of 447.4, 414.1, 389.9 and 376.0 mAh g −1 at 0.2 C, 0.5 C, 1 C and 2 C respectively and excellent cycle stability for more than 100 cycles. The possible mechanism of the unique stability of the CuS cathode was discussed.

  19. Thermal stability and in situ SiN passivation of InAlN/GaN high electron mobility heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Lugani, L.; Carlin, J.-F.; Py, M. A.; Grandjean, N. [ICMP, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

    2014-09-15

    We investigate the thermal stability of nearly lattice-matched InAlN layers under metal organic vapor phase epitaxy conditions for temperatures >800 °C and show that they are not fully stable. In particular, InAlN top layers undergo degradation during high temperature annealing due to a surface related process, which causes the loss of crystal quality. This strongly impacts the transport properties of InAlN/GaN HEMT heterostructures; in particular, the mobility is significantly reduced. However, we demonstrate that high thermal stability can be achieved by capping with a GaN layer as thin as 0.5 nm. Those findings enabled us to realize in situ passivated HEMT heterostructures with state of the art transport properties.

  20. Uranium industry in the USSR

    International Nuclear Information System (INIS)

    Nikipelov, B.V.; Chernov, A.G.

    1990-01-01

    A brief historical account of the Soviet production of natural and enriched uranium is given. The geological and geographical location of major uranium deposits are mentioned. The processing of natural ores including in-situ leaching (ISL) is also briefly described. Gas centrifuges play a large part in uranium enrichment. The role of Techsnabexport for the export of nuclear materials is explained

  1. Technical Basis for Assessing Uranium Bioremediation Performance

    International Nuclear Information System (INIS)

    PE Long; SB Yabusaki; PD Meyer; CJ Murray; AL N'Guessan

    2008-01-01

    In situ bioremediation of uranium holds significant promise for effective stabilization of U(VI) from groundwater at reduced cost compared to conventional pump and treat. This promise is unlikely to be realized unless researchers and practitioners successfully predict and demonstrate the long-term effectiveness of uranium bioremediation protocols. Field research to date has focused on both proof of principle and a mechanistic level of understanding. Current practice typically involves an engineering approach using proprietary amendments that focuses mainly on monitoring U(VI) concentration for a limited time period. Given the complexity of uranium biogeochemistry and uranium secondary minerals, and the lack of documented case studies, a systematic monitoring approach using multiple performance indicators is needed. This document provides an overview of uranium bioremediation, summarizes design considerations, and identifies and prioritizes field performance indicators for the application of uranium bioremediation. The performance indicators provided as part of this document are based on current biogeochemical understanding of uranium and will enable practitioners to monitor the performance of their system and make a strong case to clients, regulators, and the public that the future performance of the system can be assured and changes in performance addressed as needed. The performance indicators established by this document and the information gained by using these indicators do add to the cost of uranium bioremediation. However, they are vital to the long-term success of the application of uranium bioremediation and provide a significant assurance that regulatory goals will be met. The document also emphasizes the need for systematic development of key information from bench scale tests and pilot scales tests prior to full-scale implementation

  2. Technical Basis for Assessing Uranium Bioremediation Performance

    Energy Technology Data Exchange (ETDEWEB)

    PE Long; SB Yabusaki; PD Meyer; CJ Murray; AL N’Guessan

    2008-04-01

    In situ bioremediation of uranium holds significant promise for effective stabilization of U(VI) from groundwater at reduced cost compared to conventional pump and treat. This promise is unlikely to be realized unless researchers and practitioners successfully predict and demonstrate the long-term effectiveness of uranium bioremediation protocols. Field research to date has focused on both proof of principle and a mechanistic level of understanding. Current practice typically involves an engineering approach using proprietary amendments that focuses mainly on monitoring U(VI) concentration for a limited time period. Given the complexity of uranium biogeochemistry and uranium secondary minerals, and the lack of documented case studies, a systematic monitoring approach using multiple performance indicators is needed. This document provides an overview of uranium bioremediation, summarizes design considerations, and identifies and prioritizes field performance indicators for the application of uranium bioremediation. The performance indicators provided as part of this document are based on current biogeochemical understanding of uranium and will enable practitioners to monitor the performance of their system and make a strong case to clients, regulators, and the public that the future performance of the system can be assured and changes in performance addressed as needed. The performance indicators established by this document and the information gained by using these indicators do add to the cost of uranium bioremediation. However, they are vital to the long-term success of the application of uranium bioremediation and provide a significant assurance that regulatory goals will be met. The document also emphasizes the need for systematic development of key information from bench scale tests and pilot scales tests prior to full-scale implementation.

  3. A novel molten-salt electrochemical cell for investigating the reduction of uranium dioxide to uranium metal by lithium using in situ synchrotron radiation.

    Science.gov (United States)

    Brown, Leon D; Abdulaziz, Rema; Jervis, Rhodri; Bharath, Vidal; Mason, Thomas J; Atwood, Robert C; Reinhard, Christina; Connor, Leigh D; Inman, Douglas; Brett, Daniel J L; Shearing, Paul R

    2017-03-01

    A novel electrochemical cell has been designed and built to allow for in situ energy-dispersive X-ray diffraction measurements to be made during reduction of UO 2 to U metal in LiCl-KCl at 500°C. The electrochemical cell contains a recessed well at the bottom of the cell into which the working electrode sits, reducing the beam path for the X-rays through the molten-salt and maximizing the signal-to-noise ratio from the sample. Lithium metal was electrodeposited onto the UO 2 working electrode by exposing the working electrode to more negative potentials than the Li deposition potential of the LiCl-KCl eutectic electrolyte. The Li metal acts as a reducing agent for the chemical reduction of UO 2 to U, which appears to proceed to completion. All phases were fitted using Le Bail refinement. The cell is expected to be widely applicable to many studies involving molten-salt systems.

  4. Recycling of uranium by a perennial vegetation

    International Nuclear Information System (INIS)

    Thiry, Y.

    2005-01-01

    At sites of large scale mining and processing of uranium ore, tailings and waste rock piles are today the most visible relics of the uranium extractive industry. These mining relics are constantly subjected to weathering and leaching processes causing the dissemination of radioactive and toxic elements and sometimes requiring remedial operations. The in situ remediation of waste rock piles usually includes their revegetation for minimizing the water infiltration and for increasing surface soil stability. Thanks to its biomass density and longevity, the perennial vegetation plays an important role in stabilisation of the water cycling. The buffer role of forest vegetation can reduce water export from watersheds as well as erosion and hydrological losses of chemicals including radionuclides from contaminated sites. If long term reduction of contaminant dispersion at revegetated uranium mining sites is to be fully appreciated, then the extent of radioactive contaminant availability to forest vegetation and ecosystem cycling as well as the possible economic valorisation of the woody products must be considered. Concerned study focused on a Scots pine plantation established 35 years ago on a uranium waste rock pile (Wismuth GmbH) situated near Schlema (Germany). This investigation aimed at quantifying the mobility of uranium in the mining debris and its transport to the different tree compartments with emphasis on the processes involved. The influence of pine vegetation on uranium cycling dynamics was further assessed in terms of annual fluxes)

  5. Remedial action plan and site design for stabilization of the inactive uranium mill tailings sites at Slick Rock, Colorado. Final report

    International Nuclear Information System (INIS)

    1996-08-01

    This document contains the page changes for Attachment 3, Ground Water Hydrology Report dated August, 1996 for the Remedial Action Plan and Site Design for Stabilization of the Inactive Uranium Mill Tailings at Slick Rock, Colorado. This portion of Attachment 3 contains the Table of Contents pages i and ii, and pages numbered 3-3 through 3-56 of the Ground Water Hydrology Report. Also included are the cover sheets for Appendix A, B, and C to Attachment 3

  6. Literature review and preliminary analysis of inorganic ammonia pertinent to south Texas uranium in-situ leach

    International Nuclear Information System (INIS)

    Braswell, J.; Breland, M.; Chang, M.; Farley, J.; Hill, D.; Johnson, D.

    1978-01-01

    The purpose of this report is to review existing literature to aid in the determination of the potential impact of ammonia-containing lixiviants on uranium solution mining aquifers, perform studies based on the available literature, to identify potential ways to protect the groundwaters from ammonia contamination, and to propose further work where data are lacking or needed. The review of the literature includes an analysis and interpretation of the literature as it relates to the solution mining activities. Results focus on the range of geologic and hydrologic conditions representative of South Texas solution minig areas. Other pertinent data sources such as soils and agricultural literature are also reviewed and conclusions extrapolated to the solution mining situation. Specific tasks were: evaluate the potential of natural occurrence and influx of ammonia and/or nitrate species in confined aquifers typical of uranium solution mining sites; find available data on the sorption characteristics of ammonia and nitrates on pure and mixed minerals representative of South Texas geology in solution mining areas; determine applicable selectivity coefficients and kinetic data on sorption and desorption of ammonia on clay minerals; evaluate the potential for natural inorganic ammonia conversion by chemical or other mechanisms in typical solution mining aquifers; review available monitoring data from solution mining operations as it pertains to ammonia adsorption or migration; analyze and provide calculational bases for determining the predicted fate of ammonia under solution mining conditions; recommend continuation programs that focus on areas of uncertainty; provide comprehensive bibliography and abstracts of all pertinent articles

  7. Remedial action plan and site design for stabilization of the inactive uranium mill tailings site at Tuba City, Arizona

    International Nuclear Information System (INIS)

    1989-08-01

    This Remedial Action Plan (RAP) has been developed to serve a threefold purpose. It presents the series of activities which are proposed by the US Department of Energy (DOE) to accomplish long-term stabilization and control of radioactive materials at the inactive uranium processing site near Tuba City, Arizona. It provides a characterization of the present conditions of the site. It also serves to document the concurrence of the Navajo Nation, the Hopi Tribe, US Bureau of Indian Affairs (BIA), and the US Nuclear Regulatory Commission (NRC) in the remedial action. This agreement, upon execution by DOE, the Navajo Nation, and the Hopi Tribe, and concurrence by NRC, becomes Appendix B of the Cooperative Agreement. Following the introduction, contents are as follows: Section 2.0 presents the EPA standards, including a discussion of their objectives. Section 3.0 summarizes the present site characteristics and provides a definition of site-specific problems. Section 4.0 is the site design for the proposed action. Section 5.0 summarizes the plan for ensuring environmental, health, and safety protection for the surrounding community and the on-site workers. Section 6.0 presents a detailed listing of the responsibilities of the project participants. Section 7.0 describes the features of the long-term surveillance and maintenance plan. Section 8.0 presents the quality assurance aspects of the project. Section 9.0 documents the ongoing activities to keep the public informed and participating in the project

  8. Remedial action and site design for stabilization of the inactive uranium mill tailings sites at Slick Rock, Colorado

    International Nuclear Information System (INIS)

    1993-07-01

    The US Environmental Protection Agency (EPA) has established health and environmental protection regulations to correct and prevent groundwater contamination resulting from processing activities at inactive uranium milling sites (EPA, 1987). According to the Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978 Public Law (PL) 95-604 (PL 95-604), the US Department of Energy (DOE) is responsible for assessing the inactive uranium processing sites. The DOE has determined that for Slick Rock, this assessment shall include hydrogeologic site characterization for two separate uranium processing sites, the Union Carbide (UC) site and the North Continent (NC) site, and for the proposed Burro Canyon disposal site

  9. Selection of lixiviant System for the alkaline in-situ Leaching of uranium from an arkosic type of sandstone and measuring the dissolution behaviour of some metals and non-metals

    International Nuclear Information System (INIS)

    Khan, Y.; Shah, S.S.; Siddiq, M.

    2012-01-01

    A laboratory simulation study was carried out to check the possibility of alkaline in-situ leaching of uranium from an arkosic type of sandstone recovered from a specific location at a depth of 300-500 m. The ore body was overlaying impervious clay shale below the water table. Different CO/sub 3/ containing soluble salts were tested as complexing agent of the UO/sup +2/ ions along with H/sub 2/O/sub 2/ as oxidizing agent. The lixiviant system, comprising NH/sub 4/HCO/sub 3/ as complexing agent along with H/Sub 2/O/sub 2/ as oxidizing agent in concentrations of 5 g/L and 0.5 g/L respectively, was found to be the most efficient for the leaching of uranium among the 25 different compositions employed. Along with uranium, the dissolution behaviour of 15 other metals, non-metals and radicals, including eight transition metals, was also observed in the lixiviant employed. These were Na, K, Ca, Mg, Cl, SO/sub 4/, CO/sub 3/, Ti, V, Cr, Mn, Fe, Cu, Zn and Mo. It was found that the leaching of uranium compared to non-transition et als/radicals followed the trend Cl > SO > U > Na > K > Mg > Ca > CO. The comparison of uranium leaching to the transition metals was in the order U > Cr > Mo > V > Ti > Cu > Zn > Mn > Fe. Physical parameters like pH, oxidation reduction potential (ORP) and conductivity were also measured for the fresh and pregnant lixiviants. It was found that the leaching of uranium is directly related to the concentration of native soluble hexavalent uranium, contact time of the lixiviant and ore and to some extent with the total concentration of uranium as well as the porosity and permeability of the ore. (author)

  10. Grout performance in support of in situ stabilization/solidification of the GAAT tank sludges

    International Nuclear Information System (INIS)

    Spence, R.D.; Kauschinger, J.L.

    1997-05-01

    The Gunite trademark and associated tanks (GAATs) were constructed at ORNL between 1943 and 1951 and were used for many years to collect radioactive and chemical wastes. These tanks are currently inactive. Varying amounts of the sludge were removed and disposed of through the Hydrofracture Program. Thus, some tanks are virtually empty, while others still contain significant amounts of sludge and supernatant. In situ grouting of the sludges in the tanks using multi-point injection (MPI trademark), a patented, proprietary technique, is being investigated as a low-cost alternative to (1) moving the sludges to the Melton Valley Storage Tanks (MVSTs) for later solidification and disposal, (2) ex situ grouting of the sludges followed by either disposal back in the tanks or containerizing and disposal elsewhere, and (3) vitrification of the sludges. The paper discusses the chemical characteristics of the GAATs and the type of chemical surrogate that was used during the leachability tests. This is followed by the experimental work, which, consisted of scope testing and sensitivity testing. The scope testing explored the rheology of the proposed jetting slurries and the settling properties of the proposed grouts using sand-water mixes for the wet sludge. After establishing a jetting slurry and grout with an acceptable rheology and settling properties, the proposed in situ grout formulation was subjected to sensitivity testing for variations in the formulation

  11. Evaluation of human health risk from in situ recovery uranium mining, pre-and post-mining, and post-restoration

    Energy Technology Data Exchange (ETDEWEB)

    Ruedig, E.; Bhattacharyya, A.; Borch, T.; Johnson, T. [Colorado State University (United States); Till, J. [Risk Assessment Corporation (United States)

    2014-07-01

    In the United States, the restoration of in situ recovery (ISR) uranium mines is aimed at returning sites to pre-mining conditions. While this may seem an appropriate goal, little or no scientific information is available to justify utilizing baseline conditions for regulatory compliance. The chemical and radiological contaminants monitored for restoration compliance have not been evaluated to ensure they are proper indicators of the mitigation of risk. Pre-mining aquifers do not meet minimum United States drinking water standards, and must have an aquifer exemption in place prior to mining. Under these conditions, returning groundwater to near the original concentrations of contaminants may be unnecessary. Post-mining groundwater is also unlikely to meet standards for drinking water, but may be depleted in at least some toxic species as a result of the mining process. Here, we examine the risk to representative person from the personal use of groundwater sourced from an Uranium ISR mine. Water samples were collected from Cameco Resource's Smith Ranch-Highlands ISR Uranium mine near Casper, Wyoming, USA. Samples were acquired pre-mining, post-mining, and post-restoration. Concentrations of heavy metals and radionuclides were assessed by appropriate analytical techniques (e.g., mass spectroscopy or alpha spectroscopy) and these concentrations were used to estimate human health risk for three exposure scenarios: a scenario with high exposure, a scenario with medium exposure, and a scenario with low exposure. A simple biosphere transport model was constructed for each scenario to estimate the risk to humans from the use of contaminated waters for subsistence-related activities. Chemical and radiological risks were harmonized according to the United States Environmental Protection Agency's guidance for superfund sites. Each exposure scenario and its subsequent risk were evaluated individually for pre-mining, post-mining, and post-restoration aquifer waters

  12. The uranium equation in 1982

    International Nuclear Information System (INIS)

    Bonny, J.; Fulton, M.

    1983-01-01

    The subject is discussed under the headings: comparison of world nuclear generating capacity forecasts; world uranium requirements; comparison of uranium production capability forecasts; supply and demand situation in 1990 and 1995; a perspective on the uranium equation (economic factors; development lead times as a factor affecting market stability; the influence of uncertainty; the uranium market in perspective; the uranium market in 1995). (U.K.)

  13. Evaluation of growth, biochemical and bioaccumulation parameters in Pelophylax perezi tadpoles, following an in-situ acute exposure to three different effluent ponds from a uranium mine

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Sérgio M., E-mail: s.reis.marques@gmail.com [Departamento de Biologia da Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Chaves, Sandra [Universidade de Lisboa, Faculdade de Ciências, Centro de Biodiversidade, Genómica Integrativa e Funcional (BioFIG), Edifício ICAT, Campus da FCUL Campo Grande, Lisboa (Portugal); Gonçalves, Fernando [Departamento de Biologia da Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Pereira, Ruth [CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Departamento de Biologia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal)

    2013-02-15

    Mining activities invariably produce metal contaminated effluents. Depending on factors such as pH and metal concentration the toxicity of the effluent may vary. To assess the effects of three characteristically different effluent ponds from a deactivated uranium mine, with toxicologically relevant data, an in situ exposure with Pelophylax perezi tadpoles, was conducted. Tadpoles were exposed to the three effluent ponds, ranked by increasing order of metals concentrations (REF, M1, M2). Survival, growth, metal accumulation, antioxidant enzymes (catalase, glutathione peroxidase and glutathione reductase) and lipid peroxidation (LPO) were determined in tadpoles. As well, physical and chemical variables of the effluents were measured. Death percentage in the effluents was 3.17 (REF), 9.84 (M1) and 42.86% (M2) and was not coincident with metal accumulation which was highest in tadpoles exposed to M1, while metal contents in M2 tadpoles were quite similar to those recorded in REF tadpoles. However, high mortality in M2 was attributed to the extremely low pH (≈ 3.77). From the three effluents M2 tadpoles had the lowest growth and the antioxidant enzymatic activity was only affected in the case glutathione peroxidase (GPx) with significantly higher activity in M1, being in accordance with the highest accumulation of metals. LPO, usually associated with metal accumulation, had the following pattern M1 > REF > M2. Overall, effluent toxicity in tadpoles exposed to M2 effluent seems to be primarily an effect of pH while in M1 toxicity is mainly owed to high metal concentrations. The effluent acidity seems to reduce metal accumulation probably due to damage in the integument, affecting ion uptake. The results obtained bring a better understanding of the toxicological processes that local P. perezi population is subjected to, mainly in the early life stages. Furthermore this study highlights the influence of pH in the toxicity of metal rich effluents. - Highlights:

  14. Evaluation of growth, biochemical and bioaccumulation parameters in Pelophylax perezi tadpoles, following an in-situ acute exposure to three different effluent ponds from a uranium mine

    International Nuclear Information System (INIS)

    Marques, Sérgio M.; Chaves, Sandra; Gonçalves, Fernando; Pereira, Ruth

    2013-01-01

    Mining activities invariably produce metal contaminated effluents. Depending on factors such as pH and metal concentration the toxicity of the effluent may vary. To assess the effects of three characteristically different effluent ponds from a deactivated uranium mine, with toxicologically relevant data, an in situ exposure with Pelophylax perezi tadpoles, was conducted. Tadpoles were exposed to the three effluent ponds, ranked by increasing order of metals concentrations (REF, M1, M2). Survival, growth, metal accumulation, antioxidant enzymes (catalase, glutathione peroxidase and glutathione reductase) and lipid peroxidation (LPO) were determined in tadpoles. As well, physical and chemical variables of the effluents were measured. Death percentage in the effluents was 3.17 (REF), 9.84 (M1) and 42.86% (M2) and was not coincident with metal accumulation which was highest in tadpoles exposed to M1, while metal contents in M2 tadpoles were quite similar to those recorded in REF tadpoles. However, high mortality in M2 was attributed to the extremely low pH (≈ 3.77). From the three effluents M2 tadpoles had the lowest growth and the antioxidant enzymatic activity was only affected in the case glutathione peroxidase (GPx) with significantly higher activity in M1, being in accordance with the highest accumulation of metals. LPO, usually associated with metal accumulation, had the following pattern M1 > REF > M2. Overall, effluent toxicity in tadpoles exposed to M2 effluent seems to be primarily an effect of pH while in M1 toxicity is mainly owed to high metal concentrations. The effluent acidity seems to reduce metal accumulation probably due to damage in the integument, affecting ion uptake. The results obtained bring a better understanding of the toxicological processes that local P. perezi population is subjected to, mainly in the early life stages. Furthermore this study highlights the influence of pH in the toxicity of metal rich effluents. - Highlights:

  15. Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Durango, Colorado: Remedial action selection report

    International Nuclear Information System (INIS)

    1991-12-01

    The uranium mill tailings site near Durango, Colorado, was one of 24 inactive uranium mill sites designated to be remediated by the US Department of Energy (DOE) under the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). Part of the UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE's Remedial Action Plan (RAP) and certify that the remedial action conducted at the site complies with the standards promulgated by the US Environmental Protection Agency (EPA). Included in the RAP is this Remedial Action Selection Report (RAS), which has been developed to serve a two-fold purpose. First, it describes the activities that have been conducted by the DOE to accomplish remediation and long-term stabilization and control of the radioactive materials at the inactive uranium mill processing site near Durango, Colorado. Secondly, this document and the rest of the RAP, upon concurrence and execution by the DOE, the State of Colorado, and the NRC, become Appendix B of the Cooperative Agreement between the DOE and the State of Colorado

  16. Triamidoamine-uranium(IV)-stabilized terminal parent phosphide and phosphinidene complexes

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, Benedict M.; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T. [School of Chemistry, University of Nottingham (United Kingdom); Balazs, Gabor; Scheer, Manfred [Institut of Inorganic Chemistry, University of Regensburg (Germany); Tuna, Floriana; McInnes, Eric J.L. [School of Chemistry and Photon Science Institute, University of Manchester (United Kingdom)

    2014-04-22

    Reaction of [U(Tren{sup TIPS})(THF)][BPh{sub 4}] (1; Tren{sup TIPS}=N{CH_2CH_2NSi(iPr)_3}{sub 3}) with NaPH{sub 2} afforded the novel f-block terminal parent phosphide complex [U(Tren {sup TIPS})(PH{sub 2})] (2; U-P=2.883(2) Aa). Treatment of 2 with one equivalent of KCH{sub 2}C{sub 6}H{sub 5} and two equivalents of benzo-15-crown-5 ether (B15C5) afforded the unprecedented metal-stabilized terminal parent phosphinidene complex [U(Tren{sup TIPS})(PH)][K(B15C5){sub 2}] (4; U=P=2.613(2) Aa). DFT calculations reveal a polarized-covalent U=P bond with a Mayer bond order of 1.92. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Stability of gas atomized reactive powders through multiple step in-situ passivation

    Science.gov (United States)

    Anderson, Iver E.; Steinmetz, Andrew D.; Byrd, David J.

    2017-05-16

    A method for gas atomization of oxygen-reactive reactive metals and alloys wherein the atomized particles are exposed as they solidify and cool in a very short time to multiple gaseous reactive agents for the in-situ formation of a protective reaction film on the atomized particles. The present invention is especially useful for making highly pyrophoric reactive metal or alloy atomized powders, such as atomized magnesium and magnesium alloy powders. The gaseous reactive species (agents) are introduced into the atomization spray chamber at locations downstream of a gas atomizing nozzle as determined by the desired powder or particle temperature for the reactions and the desired thickness of the reaction film.

  18. Stability of Porous Platinum Nanoparticles: Combined In Situ TEM and Theoretical Study

    DEFF Research Database (Denmark)

    Chang, Shery L. Y.; Barnard, Amanda S.; Dwyer, Christian

    2012-01-01

    Porous platinum nanoparticles provide a route for the development of catalysts that use less platinum without sacrificing catalytic performance. Here, we examine porous platinum nanoparticles using a combination of in situ transmission electron microscopy and calculations based on a first-principles......-parametrized thermodynamic model. Our experimental observations show that the initially irregular morphologies of the as-sythesized porous nanoparticles undergo changes at high temperatures to morphologies having faceted external surfaces with voids present in the interior of the particles. The increasing size of stable...

  19. 78 FR 17450 - Notice of Issuance of Materials License Renewal, Operating License SUA-1341, Uranium One USA, Inc...

    Science.gov (United States)

    2013-03-21

    ... License Renewal, Operating License SUA-1341, Uranium One USA, Inc., Willow Creek Uranium In Situ Recovery.... SUA- 1341 to Uranium One USA, Inc. (Uranium One) for its Willow Creek Uranium In Situ Recovery (ISR... Commission License No. SUA-1341 For Uranium One USA, Inc., Irigaray and Christensen Ranch Projects (Willow...

  20. Clinical application for the preservation of phospho-proteins through in-situ tissue stabilization

    Directory of Open Access Journals (Sweden)

    Ding Wei

    2010-11-01

    Full Text Available Abstract Background Protein biomarkers will play a pivotal role in the future of personalized medicine for both diagnosis and treatment decision-making. While the results of several pre-clinical and small-scale clinical studies have demonstrated the value of protein biomarkers, there have been significant challenges to translating these findings into routine clinical care. Challenges to the use of protein biomarkers include inter-sample variability introduced by differences in post-collection handling and ex vivo degradation of proteins and protein modifications. Results In this report, we re-create laboratory and clinical scenarios for sample collection and test the utility of a new tissue stabilization technique in preserving proteins and protein modifications. In the laboratory setting, tissue stabilization with the Denator Stabilizor T1 resulted in a significantly higher yield of phospho-protein when compared to standard snap freeze preservation. Furthermore, in a clinical scenario, tissue stabilization at collection resulted in a higher yield of total phospho-protein, total phospho-tyrosine, pErkT202/Y204 and pAktS473 when compared to standard methods. Tissue stabilization did not have a significant effect on other post-translational modifications such as acetylation and glycosylation, which are more stable ex-vivo. Tissue stabilization did decrease total RNA quantity and quality. Conclusion Stabilization at the time of collection offers the potential to better preserve tissue protein and protein modification levels, as well as reduce the variability related to tissue processing delays that are often associated with clinical samples.

  1. Polluted soils with heavy metals. Stabilization by magnesium oxide. Ex-situ and in-situ testings; Suelos contaminados con metales pesados. Estabilizacion con oxido de magnesio. Ensayos ex situ-in situ

    Energy Technology Data Exchange (ETDEWEB)

    Cenoz, S.; Hernandez, J.; Gangutia, N.

    2004-07-01

    This work describes the use of Low-Grade MgO as a stabiliser agent for polluted soil reclaim. Low-Grade MgO may be an economically feasible alternative in the stabilisation of heavy metals from heavily contaminated soils. The effectiveness of Low-Grade MgO has been studied in three ex-situ stabilisation of heavily polluted soils contaminated by the flue-dust of pyrite roasting. LG-MgO provides an alkali reservoir guaranteeing long-term stabilisation without varying the pH conditions. The success of the ex-situ stabilisation was corroborated with the analysis of heavy metals in the leachates collected from the landfill o ver a long period of time. The study also includes the results obtained in an in-situ pilot scale stabilisation of contaminated soil. (Author) 17 refs.

  2. Real-Time Speciation of Uranium During Active Bioremediation and U(IV) Reoxidation

    International Nuclear Information System (INIS)

    Komlos, J.; Mishra, B.; Lanzirotti, A.; Myneni, S.; Jaffe, P.

    2008-01-01

    The biological reduction of uranium from soluble U(VI) to insoluble U(IV) has shown potential to prevent uranium migration in groundwater. To gain insight into the extent of uranium reduction that can occur during biostimulation and to what degree U(IV) reoxidation will occur under field relevant conditions after biostimulation is terminated, X-ray absorption near edge structure (XANES) spectroscopy was used to monitor: (1) uranium speciation in situ in a flowing column while active reduction was occurring; and (2) in situ postbiostimulation uranium stability and speciation when exposed to incoming oxic water. Results show that after 70 days of bioreduction in a high (30 mM) bicarbonate solution, the majority (>90%) of the uranium in the column was immobilized as U(IV). After acetate addition was terminated and oxic water entered the column, in situ real-time XANES analysis showed that U(IV) reoxidation to U(VI) (and subsequent remobilization) occurred rapidly (on the order of minutes) within the reach of the oxygen front and the spatial and temporal XANES spectra captured during reoxidation allowed for real-time uranium reoxidation rates to be calculated.

  3. In situ formation of magnetite reactive barriers in soil for waste stabilization

    Science.gov (United States)

    Moore, Robert C.

    2003-01-01

    Reactive barriers containing magnetite and methods for making magnetite reactive barriers in situ in soil for sequestering soil contaminants including actinides and heavy metals, organic materials, iodine and technetium are disclosed. According to one embodiment, a two-step reagent introduction into soil takes place. In the first step, free oxygen is removed from the soil by separately injecting into the soil aqueous solutions of iron (II) salt, for example FeCl.sub.2, and base, for example NaOH or NH.sub.3 in about a 1:1 volume ratio. Then, in the second step, similar reagents are injected a second time (however, according to about a 1:2 volume ratio, iron to salt) to form magnetite. The magnetite formation is facilitated, in part, due to slow intrusion of oxygen into the soil from the surface. The invention techniques are suited to injection of reagents into soil in proximity to a contamination plume or source allowing in situ formation of the reactive barrier at the location of waste or hazardous material. Mixing of reagents to form. precipitate is mediated and enhanced through movement of reagents in soil as a result of phenomena including capillary action, movement of groundwater, soil washing and reagent injection pressure.

  4. In Situ Stability of Substrate-Associated Cellulases Studied by DSC

    DEFF Research Database (Denmark)

    Borch, Kim; Cruys-Bagger, Nicolaj; Badino, Silke Flindt

    2014-01-01

    This work shows that differential scanning calorimetry (DSC) can be used to monitor the stability of substrate-adsorbed cellulases during long-term hydrolysis of insoluble cellulose. Thermal transitions of adsorbed enzyme were measured regularly in subsets of a progressing hydrolysis, and the size...

  5. In situ stabilizer formation from methacrylic acid macromonomers in emulsion polymerization

    NARCIS (Netherlands)

    Schreur-Piet, Ingeborg; Heuts, Johan P.A.

    2017-01-01

    Oligomers of methacrylic acid containing a propenyl ω-endgroup (i.e. MAA-macromonomers) were synthesized by cobalt-mediated catalytic chain transfer polymerization and used as precursors to stabilizers in emulsion polymerization. It was found that only in those polymerizations in which these

  6. Sensibility test for uranium ores from Qianjiadian sandstone type uranium deposit

    International Nuclear Information System (INIS)

    Zhang Mingyu

    2005-01-01

    Sensibility tests for uranium ores from Qianjiadian sandstone type uranium deposit in Songliao Basin which is suitable to in-situ leach are carried out, including water sensibility, velocity sensibility, salt sensibility, acid sensibility and alkaline sensibility. The sensibility critical value of this ore is determined. Some references on mining process and technical parameter are provided for in-situ leaching of uranium. (authors)

  7. Remediation of uranium contaminated water and soil by PIMS approach

    International Nuclear Information System (INIS)

    Raicevic, S.; Raicevic, J.; Smiciklas, I. . E-mail address of corresponding author: raich@beotel.yu; Raicevic, S.)

    2005-01-01

    Contamination of soil by uranium (U) represents a permanent threat for food and water resources. For this reason, remediation is a very important measure for protection of the health of the population living in the vicinity of these contaminated sites. Phosphate- Induced Metal Stabilization (PIMS) represents one of the powerful methods for remediation of soil and water contaminated by U, including depleted uranium (DU). By this approach it is possible to stabilize metals in the form of phosphate phases and other low soluble phases that are stable over geological time. PIMS is based on application of a special form of apatite of biological origin, Apatite II, to clean up metal and radionuclide contamination, in situ or ex situ. This biogenic apatite can be emplaced as a down-gradient permeable reactive barrier, mixed into contaminated soil or waste or used as a disposal liner. Here we will briefly describe the PIMS remediation protocol. (author)

  8. Kinetically controlled fabrication of gold nanorods and investigation of their thermal stability via in-situ TEM heating

    Science.gov (United States)

    Chankhunthod, N.; Aslam, Z.; Critchley, K.; Evans, S. D.; Brydson, R.

    2017-09-01

    Size controlled CTAB-capped AuNRs with various aspect ratios (ARs) ranging from 1.63±0.13 to 4.12±0.25 were synthesized following a modified seed-mediated method. Their thermal stability was examined by in-situ TEM heating. The results revealed a structural change from rods to spheres with increasing temperature. At lower temperatures 600ºC, particles became increasingly spherical. This behaviour occurred at temperatures lower than the melting point of bulk gold supporting a surface diffusion mechanism with material diffusing from the tips and redepositing at the middle of the rods. The rate of change in AR appeared to increase for thinner AuNRs.

  9. In Situ Local Measurement of Austenite Mechanical Stability and Transformation Behavior in Third-Generation Advanced High-Strength Steels

    Science.gov (United States)

    Abu-Farha, Fadi; Hu, Xiaohua; Sun, Xin; Ren, Yang; Hector, Louis G.; Thomas, Grant; Brown, Tyson W.

    2018-05-01

    Austenite mechanical stability, i.e., retained austenite volume fraction (RAVF) variation with strain, and transformation behavior were investigated for two third-generation advanced high-strength steels (3GAHSS) under quasi-static uniaxial tension: a 1200 grade, two-phase medium Mn (10 wt pct) TRIP steel, and a 980 grade, three-phase TRIP steel produced with a quenching and partitioning heat treatment. The medium Mn (10 wt pct) TRIP steel deforms inhomogeneously via propagative instabilities (Lüders and Portevin Le Châtelier-like bands), while the 980 grade TRIP steel deforms homogenously up to necking. The dramatically different deformation behaviors of these steels required the development of a new in situ experimental technique that couples volumetric synchrotron X-ray diffraction measurement of RAVF with surface strain measurement using stereo digital image correlation over the beam impingement area. Measurement results with the new technique are compared to those from a more conventional approach wherein strains are measured over the entire gage region, while RAVF measurement is the same as that in the new technique. A determination is made as to the appropriateness of the different measurement techniques in measuring the transformation behaviors for steels with homogeneous and inhomogeneous deformation behaviors. Extension of the new in situ technique to the measurement of austenite transformation under different deformation modes and to higher strain rates is discussed.

  10. Assessing phase stability and element distribution in Co-base superalloys at elevated temperatures by in situ TEM heating experiments

    Energy Technology Data Exchange (ETDEWEB)

    Eggeler, Yolita; Mueller, Julian; Spiecker, Erdmann [Lehrstuhl fuer Mikro- und Nanostrukturforschung and Center for Nanoanalysis and Electron Microscopy (CENEM), Department Werkstoffwissenschaften, Universitaet Erlangen-Nuernberg, Erlangen (Germany)

    2016-07-01

    Co-based alloys, of a composition of Co-12Al-9W, form a stable two phase γ/γ{sup '} microstructure at 900 C. γ{sup '} cubes, consisting of the L12 crystal structure are coherently embedded in a solid solution fcc (A1) γ matrix. To ensure precipitate hardening at temperatures, which are relevant to practical applications, 700-1100 C, as experienced in gas turbine applications, the stability of the γ/γ{sup '} phases is of fundamental importance. In this analysis in situ TEM studies with chip-based heating systems (by DENS solution) are applied on new Co-based superalloys. After in situ heating at apr. 900 C and controlled quenching with different quenching rates the elemental distribution at the γ/γ{sup '} interface is measured using ChemiSTEM EDX. Exploiting the driving force for interface movement resulting from temperature-dependent volume fraction of γ and γ{sup '} insight into the diffusion of individual alloying elements and the relationship between local chemistry and ordering can be gained from transient phenomena. The experimental results will be compared with theoretical calculations. This work has been carried out within the framework of the SFB-TR 103 ''Single Crystal Superalloys''.

  11. In-Situ Measurements of the Radiation Stability of Amino Acids at 15-140 K

    Science.gov (United States)

    Gerakines, Perry A.; Hudson, Reggie L.; Moore, Marla H.; Bell, Jan-Luca

    2012-01-01

    We present new kinetics data on the radiolytic destruction of amino acids measured in situ with infrared spectroscopy. Samples were irradiated at 15, 100, and 140 K with D.8-MeV protons, and amino-acid decay was followed at each temperature with and without H2O present. Observed radiation products included CO2 and amines, consistent with amino-acid decarboxylation. The half-lives of glycine, alanine, and phenylalanine were estimated for various extraterrestrial environments. Infrared spectral changes demonstrated the conversion from the non-zwitterion structure NH2-CH2(R)-COOH at 15 K to the zwitterion structure +NH3-CH2(R)-COO- at 140 K for each amino acid studied.

  12. Engineering feasibility analysis for in-situ stabilization of Burrell Township site residues

    International Nuclear Information System (INIS)

    1982-11-01

    The Burrell Township site, located in western Pennsylvania, received approximately 11,600 tons of radioactively-contaminated material in late 1956 and early 1957 from the Vitro Manufacturing Company's operations in Canonsburg, Pennsylvania. WESTON was requested to conduct an engineering study to determine the feasibility of stabilizing the site in accordance with the US Environmental Protection Agency's (EPA) interim and proposed standards (45 FR 27366--27368, April 22, 1980, and 46 FR 2556--2563, January 9, 1981). The scope of this study is limited to those alternatives that can be implemented on the site and will not require removal and offsite disposal of radioactively-contaminated material. Four alternatives for control of the radioactive material at the Burrell site were considered and evaluated, as follows: 1. Site stabilization and closure. 2. Site control and containment. 3. Waste excavation and encapsulation. 4. Waste excavation, incineration, and encapsulation. 2 refs., 32 figs., 12 tabs

  13. Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Gunnison, Colorado

    International Nuclear Information System (INIS)

    1992-10-01

    The US Environmental Protection Agency (EPA) has established health and environmental protection regulations to correct and prevent groundwater contamination resulting from processing activities at inactive uranium milling sites (40 CFR 192). The US Department of Energy (DOE) is responsible for assessing the inactive uranium processing sites. The DOE has determined this assessment shall include information on hydrogeologic site characterization. This document contains appendices to Attachment 3, Groundwater Hydrology Report included are calculations

  14. Field application of activated carbon amendment for in-situ stabilization of polychlorinated biphenyls in marine sediment.

    Science.gov (United States)

    Cho, Yeo-Myoung; Ghosh, Upal; Kennedy, Alan J; Grossman, Adam; Ray, Gary; Tomaszewski, Jeanne E; Smithenry, Dennis W; Bridges, Todd S; Luthy, Richard G

    2009-05-15

    We report results on the first field-scale application of activated carbon (AC) amendment to contaminated sediment for in-situ stabilization of polychlorinated biphenyls (PCBs). The test was performed on a tidal mud flat at South Basin, adjacent to the former Hunters Point Naval Shipyard, San Francisco Bay, CA. The major goals of the field study were to (1) assess scale up of the AC mixing technology using two available, large-scale devices, (2) validate the effectiveness of the AC amendment at the field scale, and (3) identify possible adverse effects of the remediation technology. Also, the test allowed comparison among monitoring tools, evaluation of longer-term effectiveness of AC amendment, and identification of field-related factors that confound the performance of in-situ biological assessments. Following background pretreatment measurements, we successfully incorporated AC into sediment to a nominal 30 cm depth during a single mixing event, as confirmed by total organic carbon and black carbon contents in the designated test plots. The measured AC dose averaged 2.0-3.2 wt% and varied depending on sampling locations and mixing equipment. AC amendment did not impact sediment resuspension or PCB release into the water column over the treatment plots, nor adversely impactthe existing macro benthic community composition, richness, or diversity. The PCB bioaccumulation in marine clams was reduced when exposed to sediment treated with 2% AC in comparison to the control plot Field-deployed semi permeable membrane devices and polyethylene devices showed about 50% reduction in PCB uptake in AC-treated sediment and similar reduction in estimated pore-water PCB concentration. This reduction was evident even after 13-month post-treatment with then 7 months of continuous exposure, indicating AC treatment efficacy was retained for an extended period. Aqueous equilibrium PCB concentrations and PCB desorption showed an AC-dose response. Field-exposed AC after 18 months

  15. Uranium Mill Tailings Management

    International Nuclear Information System (INIS)

    Nelson, J.D.

    1982-01-01

    This book presents the papers given at the Fifth Symposium on Uranium Mill Tailings Management. Advances made with regard to uranium mill tailings management, environmental effects, regulations, and reclamation are reviewed. Topics considered include tailings management and design (e.g., the Uranium Mill Tailings Remedial Action Project, environmental standards for uranium mill tailings disposal), surface stabilization (e.g., the long-term stability of tailings, long-term rock durability), radiological aspects (e.g. the radioactive composition of airborne particulates), contaminant migration (e.g., chemical transport beneath a uranium mill tailings pile, the interaction of acidic leachate with soils), radon control and covers (e.g., radon emanation characteristics, designing surface covers for inactive uranium mill tailings), and seepage and liners (e.g., hydrologic observations, liner requirements)

  16. Field Deployment for In-situ Metal and Radionuclide Stabilization by Microbial Metabolites

    Energy Technology Data Exchange (ETDEWEB)

    Turick, C. E.; Knox, A. S.; Dixon, K. L.; Roseberry, R. J.; Kritzas, Y. G

    2005-09-26

    A novel biotechnology is reported here that was demonstrated at SRS that facilitates metal and actinide immobilization by incorporating the physiology and ecology of indigenous bacteria. This technology is based on our previous work with pyomelanin-producing bacteria isolated from SRS soils. Through tyrosine supplementation, overproduction of pyomelanin was achieved, which lead ultimately to metal and actinide immobilization, both in-vitro and in-situ. Pyomelanin is a recalcitrant microbial pigment and a humic type compound in the class of melanin pigments. Pyomelanin has electron shuttling and metal chelation capabilities and thus accelerates the bacterial reduction and/or immobilization of metals. Pyomelanin is produced outside the cell and either diffuses away or attaches to the cell surface. In either case, the reduced pyomelanin is capable of transferring electrons to metals as well as chelating metals. Because of its recalcitrance and redox cycling properties, pyomelanin molecules can be used over and over again for metal transformation. When produced in excess, pyomelanin produced by one bacterial species can be used by other species for metal reduction, thereby extending the utility of pyomelanin and further accelerating metal immobilization rates. Soils contaminated with Ni and U were the focus of this study in order to develop in-situ, metal bioimmobilization technologies. We have demonstrated pyomelanin production in soil from the Tims Branch area of SRS as a result of tyrosine amendments. These results were documented in laboratory soil column studies and field deployment studies. The amended soils demonstrated increased redox behavior and sequestration capacity of U and transition metals following pyomelanin production. Treatments incorporating tyrosine and lactate demonstrated the highest levels of pyomelanin production. In order to determine the potential use of this technology at other areas of SRS, pyomelanin producing bacteria were also quantified

  17. A novel strategy for high-stability lithium sulfur batteries by in situ formation of polysulfide adsorptive-blocking layer

    Science.gov (United States)

    Jin, Liming; Li, Gaoran; Liu, Binhong; Li, Zhoupeng; Zheng, Junsheng; Zheng, Jim P.

    2017-07-01

    Lithium sulfur (Lisbnd S) batteries are one of the most promising energy storage devices owing to their high energy and power density. However, the shuttle effect as a key barrier hinders its practical application by resulting in low coulombic efficiency and poor cycling performance. Herein, a novel design of in situ formed polysulfide adsorptive-blocking layer (PAL) on the cathode surface was developed to tame the polysulfide shuttling and promote the cycling stability for Lisbnd S batteries. The PAL is consisted of La2S3, which is capable to chemically adsorb polysulfide via the strong interaction of Lasbnd S bond and Ssbnd S bond, and build an effective barrier against sulfur escaping. Moreover, the La2S3 is capable to suppress the crystallization of Li2S and promote the ion transfer, which contributes to the reduced internal resistance of batteries. Furthermore, the by-product LiNO3 simultaneously forms a stable anode solid and electrolyte interface to further inhibit the polysulfide shuttle. By this simple and convenient method, the resultant Lisbnd S batteries achieved exceptional cycling stability with an ultralow decay rate of 0.055% since the 10th cycle.

  18. Development of cellulase-nanoconjugates with enhanced ionic liquid and thermal stability for in situ lignocellulose saccharification.

    Science.gov (United States)

    Grewal, Jasneet; Ahmad, Razi; Khare, S K

    2017-10-01

    The present work aimed to improve catalytic efficiency of Trichoderma reesei cellulase for enhanced saccharification. The cellulase was immobilized on two nanomatrices i.e. magnetic and silica nanoparticles with immobilization efficiency of 85% and 76% respectively. The nanobioconjugates exhibited increase in V max , temperature optimum, pH and thermal stability as compared with free enzyme. These could be efficiently reused for five repeated cycles and were stable in 1-ethyl-3-methylimidazoliumacetate [EMIM][Ac], an ionic liquid. Ionic liquids (IL) are used as green solvents to dissolve lignocellulosic biomass and facilitate better saccharification. The cellulase immobilized on magnetic nanoparticles was used for in situ saccharification of [EMIM][Ac] pretreated sugarcane bagasse and wheat straw for two cycles. The structural deconstruction and decrease in biomass crystallinity was confirmed by SEM, XRD and FTIR. The high hydrolysis yields (∼89%) obtained in this one-pot process coupled with IL stability and recycled use of immobilized cellulase, potentiates its usefulness in biorefineries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Non-Aqueous Sol-Gel Synthesis of FePt Nanoparticles in the Absence of In Situ Stabilizers

    Directory of Open Access Journals (Sweden)

    Tobias Preller

    2018-05-01

    Full Text Available The synthesis of FePt nanocrystals is typically performed in an organic solvent at rather high temperatures, demanding the addition of the in situ stabilizers oleic acid and oleylamine to produce monomodal particles with well-defined morphologies. Replacing frequently-used solvents with organic media bearing functional moieties, the use of the stabilizers can be completely circumvented. In addition, various morphologies and sizes of the nanocrystals can be achieved by the choice of organic solvent. The kinetics of particle growth and the change in the magnetic behavior of the superparamagnetic FePt nanocrystals during the synthesis with a set of different solvents, as well as the resulting morphologies and stoichiometries of the nanoparticles were determined by powder X-ray diffraction (PXRD, small-angle X-ray scattering (SAXS, transmission electron microscopy (TEM, inductively coupled plasma optical emission spectroscopy (ICP-OES/mass spectrometry (ICP-MS, and superconducting quantum interference device (SQUID measurements. Furthermore, annealing of the as-prepared FePt nanoparticles led to the ordered L10 phase and, thus, to hard magnetic materials with varying saturation magnetizations and magnetic coercivities.

  20. Optical and structural properties of radiolytically in situ synthesized silver nanoparticles stabilized by chitosan/poly(vinyl alcohol) blends

    International Nuclear Information System (INIS)

    Krstić, Jelena; Spasojević, Jelena; Radosavljević, Aleksandra; Šiljegovć, Milorad; Kačarević-Popović, Zorica

    2014-01-01

    In this study, the potential of chitosan/poly(vinyl alcohol) (CS/PVA) blends as capping agent for stabilization of Ag-nanoparticles (Ag NPs) during their in situ gamma irradiation induced synthesis was investigated. The UV–vis absorption spectra show the surface plasmon absorption band around 410 nm, which confirms the formation of Ag-nanoparticles. It was found that the composition of CS/PVA blend affected the size of the obtained Ag-nanoparticles, as well as the parameters such as density, molar concentration and effective surface area, calculated from the experimentally obtained UV–vis absorption spectra and spectra obtained by simulation according to the Mie theory. SEM micrograph and XRD measurement indicated a spherical morphology and face centered cubic crystal structure of Ag-nanoparticles, with diameter around 12 nm. The values of optical band gap energy between valence and conduction bands (E g ), calculated from the UV–vis absorption spectra, also show dependence on the blend composition for Ag–CS/PVA colloids as well as for Ag–CS/PVA nanocomposites. - Highlights: • Ag NPs were synthesized by γ-irradiation and stabilized by CS/PVA blends. • Composition of CS/PVA blends has influence on the size of spherical Ag NPs. • simulation based on Mie theory was used to calculate the parameters of Ag NPs. • Ag NPs are stabilized through interactions with -OH and -NH 2 groups of polymers. • Optical band gap energy was calculated from UV–vis spectra by Tauc's expression

  1. Pyrophoric behaviour of uranium hydride and uranium powders

    Science.gov (United States)

    Le Guyadec, F.; Génin, X.; Bayle, J. P.; Dugne, O.; Duhart-Barone, A.; Ablitzer, C.

    2010-01-01

    Thermal stability and spontaneous ignition conditions of uranium hydride and uranium metal fine powders have been studied and observed in an original and dedicated experimental device placed inside a glove box under flowing pure argon. Pure uranium hydride powder with low amount of oxide (Oxidation mechanisms are proposed.

  2. Remedial Action Plan and final design for stabilization of the inactive uranium mill tailings at Green River, Utah. Volume 1, Text, Appendices A, B, and C: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, M.L. [USDOE Albuquerque Operations Office, NM (United States). Uranium Mill Tailings Remedial Action Project Office; Alkema, K. [Utah Dept. of Health, Salt Lake City, UT (United States). Environmental Health Div.

    1991-03-01

    This Remedial Action Plan (RAP) has been developed to serve a threefold purpose. It presents the series of activities that are proposed by the US Department of Energy (DOE) to accomplish long-term stabilization and control of radioactive materials at the inactive uranium processing site located near Green River, Utah. It provides a characterization of the present conditions of the site. It also serves to document the concurrence of the state of Utah and the US Nuclear Regulatory Commission (NRC) in the remedial action. This agreement, upon execution by the DOE and the state of Utah, and concurrence by the NRC, becomes Appendix 8 of the Cooperative Agreement.

  3. Remedial action plan and site conceptual design for stabilization of the inactive uranium mill tailings site at Ambrosia Lake, New Mexico

    International Nuclear Information System (INIS)

    Matthews, M.L.; Mitzelfelt, R.

    1991-11-01

    This Remedial Action Plan (RAP) has been developed to serve a dual purpose. It presents the series of activities that is proposed by the US Department of Energy (DOE) to stabilize and control radioactive materials at the inactive Phillips/United Nuclear uranium processing site designated as the Ambrosia Lake site in McKinley County, New Mexico. It also serves to document the concurrence of both State of New Mexico and the US Nuclear Regulatory Commission (NRC) in the remedial action. This agreement, upon execution by the DOE and the state and concurrence by NRC, becomes Appendix B of the Cooperative Agreement

  4. Stabilized Sulfonated Aromatic Polymers by in situ Solvothermal Cross-Linking

    Energy Technology Data Exchange (ETDEWEB)

    Di Vona, Maria Luisa, E-mail: divona@uniroma2.it; Sgreccia, Emanuela [Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Rome (Italy); Narducci, Riccardo; Pasquini, Luca [Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Rome (Italy); MAtériaux Divisés, Interfaces, Réactivité, ELectrochimie (MADIREL – UMR 7246), Aix Marseille Université, Marseille (France); Hou, Hongying [Faculty of Material and Engineering, Kunming University of Science and Technology, Kunming (China); Knauth, Philippe [MAtériaux Divisés, Interfaces, Réactivité, ELectrochimie (MADIREL – UMR 7246), Aix Marseille Université, Marseille (France)

    2014-10-10

    The cross-link reaction via sulfone bridges of sulfonated polyether ether ketone (SPEEK) by thermal treatment at 180°C in presence of dimethylsulfoxide is discussed. The modifications of properties subsequent to the cross-linking are presented. The mechanical strength as well as the hydrolytic stability increased with the thermal treatment time, i.e., with the degree of cross-linking. The proton conductivity was determined as function of temperature, IEC, degree of cross-linking, and hydration number. The memory effect, which is the membrane ability to “remember” the water uptake reached at high temperature also at lower temperature, is exploited in order to achieve high values of conductivity. Membranes swelled at 110°C can reach a conductivity of 0.14 S/cm at 80°C with a hydration number (λ) of 73.

  5. Stabilized sulfonated aromatic polymers by in situ solvothermal cross-linking

    Directory of Open Access Journals (Sweden)

    Maria Luisa eDi Vona

    2014-10-01

    Full Text Available The cross-link reaction via sulfone bridges of sulfonated polyetheretherketone (SPEEK by thermal treatment at 180 °C in presence of dimethylsulfoxide (DMSO is discussed. The modifications of properties subsequent to the cross-linking are presented. The mechanical strength as well as the hydrolytic stability increased with the thermal treatment time, i.e., with the degree of cross-linking. The proton conductivity was determined as function of temperature, IEC, degree of cross-linking and hydration number. The memory effect, which is the membrane ability to remember the water uptake reached at high temperature also at lower temperature, is exploited in order to achieve high values of conductivity. Membranes swelled at 110 °C can reach a conductivity of 0.14 S/cm at 80°C with a hydration number ( of 73.

  6. Uranium mining

    International Nuclear Information System (INIS)

    Cheeseman, E.W.

    1980-01-01

    The international uranium market appears to be currently over-supplied with a resultant softening in prices. Buyers on the international market are unhappy about some of the restrictions placed on sales by the government, and Canadian sales may suffer as a result. About 64 percent of Canada's shipments come from five operating Ontario mines, with the balance from Saskatchewan. Several other properties will be producing within the next few years. In spite of the adverse effects of the Three Mile Island incident and the default by the T.V.A. of their contract, some 3 600 tonnes of new uranium sales were completed during the year. The price for uranium had stabilized at US $42 - $44 by mid 1979, but by early 1980 had softened somewhat. The year 1979 saw the completion of major environmental hearings in Ontario and Newfoundland and the start of the B.C. inquiry. Two more hearings are scheduled for Saskatchewan in 1980. The Elliot Lake uranium mining expansion hearings are reviewed, as are other recent hearings. In the production of uranium for nuclear fuel cycle, environmental matters are of major concern to the industry, the public and to governments. Research is being conducted to determine the most effective method for removing radium from tailings area effluents. Very stringent criteria are being drawn up by the regulatory agencies that must be met by the industry in order to obtain an operating licence from the AECB. These criteria cover seepages from the tailings basin and through the tailings retention dam, seismic stability, and both short and long term management of the tailings waste management area. (auth)

  7. Nuclear and uranium policies

    International Nuclear Information System (INIS)

    MacNabb, G.M.; Uranium Canada Ltd., Ottawa, Ontario)

    The background of the uranium industry in Canada is described. Government policies with respect to ownership of the uranium mining industry, price stabilization, and especially reservation of sufficient supplies of nuclear fuels for domestic utilities, are explained. Canadian policy re nuclear exports and safeguards is outlined. (E.C.B.)

  8. In situ high-frequency UV-Vis spectrometer probes for investigating runoff processes and end member stability.

    Science.gov (United States)

    Schwab, Michael; Weiler, Markus; Pfister, Laurent; Klaus, Julian

    2014-05-01

    In recent years, several limitations as to the application of end member mixing analysis with isotope and geochemical tracers have been revealed: unstable end member solutions, inputs varying in space and time, and unrealistic mixing assumptions. In addition, the necessary high-frequency sampling using conventional methods is time and resources consuming, and hence most sampling rates are not suitable for capturing the response times of the majority of observed headwater catchments. However, high-frequency observations are considered fundamental for gaining new insights into hydrological systems. In our study, we have used two portable, in situ, high-frequency UV-Vis spectrometers (spectro::lyser; scan Messtechnik GmbH) to investigate the variability of several signatures in streamflow and end member stability. The spectro::lyser measures TOC, DOC, nitrate and the light absorption spectrum from 220 to 720 nm with 2.5 nm increment. The Weierbach catchment (0.45 km2) in the Attert basin (297 km2) in Luxemburg is a small headwater research catchment (operated by the CRP Gabriel Lippmann), which is completely forested and underlain by schist bedrock. The catchment is equipped with a dense network of hydrological instruments and for this study, the outlet of the Weierbach catchment was equipped with one spectro::lyser, permanently sensing stream water at a 15 minutes time step over several months. Hydrometric and meteorologic data was compared with the high-frequency spectro::lyser time series of TOC, DOC, nitrate and the light absorption spectrum, to get a first insight into the behaviour of the catchment under different environmental conditions. As a preliminary step for a successful end member mixing analysis, the stability of rainfall, soil water, and groundwater was tested with one spectro::lyser, both temporally and spatially. Thereby, we focused on the investigation of changes and patterns of the light absorption spectrum of the different end members and the

  9. Environmental aspects of sulphuric acid in situ leach uranium mining in the permafrost zone (Vitim District, Russian Federation)

    International Nuclear Information System (INIS)

    Fazlullin, M.I.; Boitsov, A.V.

    2002-01-01

    Currently in situ leaching pilot tests are in progress at the Khiagda deposit, Vitim District, Russian Federation. The deposit is of the sandstone basal channel type, or paleovalley type in the Russian classification. It contains about 15 000 mt U at an ore grade averaging 0.05% U. Mineralization occurs in permeable unconsolidated Neogene fluvial sediments located below the permafrost which extends to 100 m deep. The basement rock is Paleozoic granite. Neogene-Quaternary basalts overlap the ore hosting sediments. The thickness of the ore host horizon varies from a few meters to 120 m. The depth of mineralization averages 170 m. Ore bodies are of lens and strataform shape. The following types of underground waters have been identified: groundwaters of the near surface or active layer, the aquifer in the Neogene volcanics, the ore host aquifer of the Neogene permeable sediments and fault related waters. The permeability in the ore bearing horizon varies from 0.1 to 20 m/day (averages 2 to 3 m/day). The waters of the productive aquifer are not suitable for industrial nor potable water supply due to their initial chemical composition. The ore host horizons occur between two impermeable horizons, which confine leaching solutions. Using sulphuric acid solutions as leaching reagent decreases the pH and increases Total Dissolved Solids (TDS) of the groundwaters within the leaching area due to concentration of sulphate-ion and other dissolved components. Principal components contaminating the underground waters are sulphates of aluminium, manganese, nickel and chrome. Their content during leaching significantly exceeds initial values. The available information on residual acid migration with the ground water shows that the concentration of contaminants significantly decreases away from the leaching contour. This occurs due to precipitation of contaminants during migration of the underground water from ISL sites. The external contour of the contamination aureole is defined

  10. [Research on the application of in-situ biological stabilization solidification technology in chromium contaminated site management].

    Science.gov (United States)

    Zhang, Jian-rong; Li, Juan; Xu, Wei

    2013-09-01

    In-situ biological stabilization solidification (SS) technology is an effective ground water risk control method for chromium contaminated sites. Through on-site engineering test, this paper has preliminarily validated the remediation effect of in-situ SS method on a southern chromium contaminated site. The engineering test site has an area of approximately 600 m2, and is located at the upstream of the contaminated area. Due to the severe contamination of chromium, the total chromium concentration reached up to 11,850 mg x kg(-1), while the hexavalent chromium concentration reached up to 349 mg x kg(-1), and the most severely contaminated soil had a depth of -0.5 - -2 m. Variations in hexavalent chromium and total chromium concentration in groundwater were observed through the injection of reducing agents and microbial regulators into the injection wells in the test site, and through the monitoring analysis at different time and different depth under the action of the injection agents. Results of the engineering test showed that the on-site SS technology significantly changed the chromium speciation in soil and then reduced the migration of chromium, thus the groundwater risk was reduced. The injected agents had a good effect of hexavalent chromium remediation in groundwater within the effective range of the injection wells, and the SS rate of hexavalent chromium into trivalent chromium reached 94%-99.9%, the SS rate of total chromium fixation reached 83.9%-99.8%. The test results are of significant reference value for the remediation of contaminated sites with features of shallow groundwater depth and soil mainly consisting of silty clay and sandy clay.

  11. Design of top covers supporting aerobic in situ stabilization of old landfills - An experimental simulation in lysimeters

    Energy Technology Data Exchange (ETDEWEB)

    Hrad, Marlies [Institute of Waste Management, Department of Water-Atmosphere-Environment, University of Natural Resources and Life Sciences, Muthgasse 107, 1190 Vienna (Austria); Huber-Humer, Marion, E-mail: marion.huber-humer@boku.ac.at [Institute of Waste Management, Department of Water-Atmosphere-Environment, University of Natural Resources and Life Sciences, Muthgasse 107, 1190 Vienna (Austria); Wimmer, Bernhard; Reichenauer, Thomas G. [Health and Environment Department, Environmental Resources and Technologies, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Strasse 24, 3430 Tulln (Austria)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Tested engineered covers as surrogate to gas extraction during and after in situ aeration. Black-Right-Pointing-Pointer Examined how covers influence gas emissions, water balance and leachate generation. Black-Right-Pointing-Pointer Investigated effect of top covers on air-distribution in waste mass during aeration. Black-Right-Pointing-Pointer We suggest criteria and cover design to meet the demands during and after aeration. Black-Right-Pointing-Pointer Such cover systems may offer greenhouse gas emission reduction also after active aeration. - Abstract: Landfill aeration by means of low pressure air injection is a promising tool to reduce long term emissions from organic waste fractions through accelerated biological stabilization. Top covers that enhance methane oxidation could provide a simple and economic way to mitigate residual greenhouse gas emissions from in situ aerated landfills, and may replace off-gas extraction and treatment, particularly at smaller and older sites. In this respect the installation of a landfill cover system adjusted to the forced-aerated landfill body is of great significance. Investigations into large scale lysimeters (2 Multiplication-Sign 2 Multiplication-Sign 3 m) under field conditions have been carried out using different top covers including compost materials and natural soils as a surrogate to gas extraction during active low pressure aeration. In the present study, the emission behaviour as well as the water balance performance of the lysimeters has been investigated, both prior to and during the first months of in situ aeration. Results reveal that mature sewage sludge compost (SSC) placed in one lysimeter exhibits in principle optimal ambient conditions for methanotrophic bacteria to enhance methane oxidation. Under laboratory conditions the mature compost mitigated CH{sub 4} loadings up to 300 l CH{sub 4}/m{sup 2} d. In addition, the compost material provided high air permeability

  12. Uranium of Kazakhstan

    International Nuclear Information System (INIS)

    Tsalyuk, Yu.; Gurevich, D.

    2000-01-01

    Over 25 % of the world's uranium reserves are concentrated in Kazakhstan. So, the world's largest Shu-Sarysu uranium province is situated on southern Kazakhstan, with resources exceeding 1 billion tonnes of uranium. No less, than 3 unique deposits with resources exceeding 100,000 tonnes are situated here. From the economic point of view the most important thing is that these deposits are suitable for in-situ leaching, which is the cheapest, environmentally friendly and most efficient method available for uranium extracting. In 1997 the Kazatomprom National Joint-Stock Company united all Kazakhstan's uranium enterprises (3 mine and concentrating plants, Volkovgeologiya Joint-Stock Company and the Ulbinskij Metallurgical plant). In 1998 uranium production came to 1,500 tonnes (860 kg in 1997). In 1999 investment to the industry were about $ 30 million. Plans for development of Kazakhstan's uranium industry provide a significant role for foreign partners. At present, 2 large companies (Comeco (Canada), Cogema (France) working in Kazakhstan. Kazakatomprom continues to attract foreign investors. The company's administration announced that in that in next year they have plan to make a radical step: to sell 67 % of stocks to strategic investors (at present 100 % of stocks belongs to state). Authors of the article regard, that the Kazakhstan's uranium industry still has significant reserves to develop. Even if the scenario for the uranium industry could be unfavorable, uranium production in Kazakhstan may triple within the next three to four years. The processing of uranium by the Ulbinskij Metallurgical Plant and the production of some by-products, such as rhenium, vanadium and rare-earth elements, may provide more profits. Obviously, the sale of uranium (as well as of any other reserves) cannot make Kazakhstan a prosperous country. However, country's uranium industry has a god chance to become one of the most important and advanced sectors of national economy

  13. Uranium exploration, mining and ore enrichment techniques

    International Nuclear Information System (INIS)

    Fuchs, H.D.; Wentzlau, D.

    1985-01-01

    The paper describes the different types of uranium deposits and their importance. It is shown that during the present depressed uranium market situation, mainly high grade deposits such as unconformity-related deposits can be mined economically. The different successive exploration steps are outlined including methods used for uranium. Uranium mining does not greatly differ from normal mining, but the uranium metallurgy needs its own specialized but already classic technology. Only a relative small amount of uranium can be expected from projects where uranium is produced by in situ leach methods or by extraction from phosphoric acid. A short summary of investment costs and operating costs is given for an average uranium mine. The last chapter deals with the definition of different reserve categories and outlines the uranium reserves of the western world including the uranium production (1983) and the expected uranium production capacity for 1985 and 1990. (orig.) [de

  14. Remedial action plan and site design for stabilization of the inactive uranium mill tailings sites at Slick Rock, Colorado: Remedial Action Selection Report. Preliminary final

    Energy Technology Data Exchange (ETDEWEB)

    1994-03-01

    This proposed remedial action plan incorporates the results of detailed investigation of geologic, geomorphic, and seismic conditions at the proposed disposal site. The proposed remedial action will consist of relocating the uranium mill tailings, contaminated vicinity property materials, demolition debris, and windblown/waterborne materials to a permanent repository at the proposed Burro Canyon disposal cell. The proposed disposal site will be geomorphically stable. Seismic design parameters were developed for the geotechnical analyses of the proposed cell. Cell stability was analyzed to ensure long-term performance of the disposal cell in meeting design standards, including slope stability, settlement, and liquefaction potential. The proposed cell cover and erosion protection features were also analyzed and designed to protect the RRM (residual radioactive materials) against surface water and wind erosion. The location of the proposed cell precludes the need for permanent drainage or interceptor ditches. Rock to be used on the cell top-, side-, and toeslopes was sized to withstand probable maximum precipitation events.

  15. Characterization of single crystal uranium-oxide thin films grown via reactive-gas magnetron sputtering on yttria-stabilized zirconia and sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Strehle, Melissa M.; Heuser, Brent J., E-mail: bheuser@illinois.edu; Elbakhshwan, Mohamed S.; Han Xiaochun; Gennardo, David J.; Pappas, Harrison K.; Ju, Hyunsu

    2012-06-30

    The microstructure and valence states of three single crystal thin film systems, UO{sub 2} on (11{sup Macron }02) r-plane sapphire, UO{sub 2} on (001) yttria-stabilized zirconia, and U{sub 3}O{sub 8} on (11{sup Macron }02) r-plane sapphire, grown via reactive-gas magnetron sputtering are analyzed primarily with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy (UPS). XRD analysis indicates the growth of single crystal domains with varying degrees of mosaicity. XPS and UPS analyses yield U-4f, U-5f, O-1s, and O-2p electron binding energies consistent with reported bulk values. A change from p-type to n-type semiconductor behavior induced by preferential sputtering of oxygen during depth profile analysis was observed with both XPS and UPS. Trivalent cation impurities (Nd and Al) in UO{sub 2} lower the Fermi level, shifting the XPS spectral weight. This observation is consistent with hole-doping of a Mott-Hubbard insulator. The uranium oxide-(11{sup Macron }02) sapphire system is unstable with respect to Al interdiffusion across the film-substrate interface at elevated temperature. - Highlights: Black-Right-Pointing-Pointer Single crystal uranium-oxides grown on sapphire and yttria-stabilized zirconia. Black-Right-Pointing-Pointer Anion and cation valence states studied by photoelectron emission spectroscopy. Black-Right-Pointing-Pointer Trivalent Nd and Al impurities lower the Fermi level. Black-Right-Pointing-Pointer Uranium-oxide films on sapphire found to be unstable with respect to Al interdiffusion.

  16. Phospholyl-uranium complexes

    International Nuclear Information System (INIS)

    Gradoz, Philippe

    1993-01-01

    After having reported a bibliographical study on penta-methylcyclopentadienyl uranium complexes, and a description of the synthesis and radioactivity of uranium (III) and (IV) boron hydrides compounds, this research thesis reports the study of mono and bis-tetramethyl-phospholyl uranium complexes comprising chloride, boron hydride, alkyl and alkoxide ligands. The third part reports the comparison of structures, stabilities and reactions of homologue complexes in penta-methylcyclopentadienyl and tetramethyl-phospholyl series. The last part addresses the synthesis of tris-phospholyl uranium (III) and (IV) complexes. [fr

  17. On the thermal stability of ultrafine-grained Al stabilized by in-situ amorphous Al{sub 2}O{sub 3} network

    Energy Technology Data Exchange (ETDEWEB)

    Balog, Martin, E-mail: martin.balog@savba.sk [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 83102 Bratislava (Slovakia); Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States); Hu, Tao [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States); Krizik, Peter [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 83102 Bratislava (Slovakia); Castro Riglos, Maria Victoria [Centro Atómico Bariloche, Av. Bustillo 9.500 (8400) Bariloche, Río Negro (Argentina); Saller, Brandon D.; Yang, Hanry; Schoenung, Julie M.; Lavernia, Enrique J. [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States)

    2015-11-11

    Bulk Al materials with average grain sizes of 0.47 and 2.4 µm, were fabricated by quasi-isostatic forging consolidation of two types of Al powders with average particle sizes of 1.3 and 8.9 μm, respectively. By utilizing the native amorphous Al{sub 2}O{sub 3} (am-Al{sub 2}O{sub 3}) film on the Al powders surfaces, a continuous, ∼7 nm thick, am-Al{sub 2}O{sub 3} network was formed in situ in the Al specimens. Systematic investigation of the changes to the am-Al{sub 2}O{sub 3} network embedded in the Al matrix upon heating and annealing up to 600 °C was performed by transmission electron microscopy (TEM). At the same time, the stability of the Al grain structure was studied by transmission Kikuchi diffraction (TKD), electron back-scatter diffraction (EBSD), and TEM. The am-Al{sub 2}O{sub 3} network remained stable after annealing at 400 °C for 24 h. In-situ TEM studies revealed that at temperatures ≥450 °C, phase transformation of the am-Al{sub 2}O{sub 3} network to crystalline γ-Al{sub 2}O{sub 3} particles occurred. After annealing at 600 °C for 24 h the transformation was completed, whereby only nanometric γ-Al{sub 2}O{sub 3} particles with an average size of 28 nm resided on the high angle grain boundaries of Al. Due to the pinning effect of γ-Al{sub 2}O{sub 3}, the Al grain and subgrain structures remained unchanged during annealing up to 600 °C for 24 h. The effect of the am-Al{sub 2}O{sub 3}→γ-Al{sub 2}O{sub 3} transformation on the mechanical properties of ultrafine- and fine-grained Al is discussed from the standpoint of the underlying mechanisms.

  18. Radiation damage of metal uranium

    International Nuclear Information System (INIS)

    Mihajlovic, A.

    1965-01-01

    This report is concerned with the role of dispersion second phase in uranium and burnup rate. The role of dispersion phases in radiation stability of metal uranium was studies by three methods: variation of electric conductivity dependent on the neutron flux and temperature of pure uranium for different states of dispersion second phase; influence of dispersion phase on the radiation creep; transmission electron microscopy of fresh and irradiated uranium

  19. Remedial action plan and site design for stabilization of the inactive uranium mill tailings site at Lowman, Idaho

    International Nuclear Information System (INIS)

    1991-09-01

    The US Environmental Protection Agency (EPA) has established health and environmental regulations to correct and prevent groundwater contamination resulting from former uranium processing activities at inactive uranium processing sites (40 CFR 192). According to the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), the US Department of Energy (DOE) is responsible for assessing the inactive uranium processing sites. The DOE has decided that each assessment shall include information on hydrogeologic site characterization. The water resources protection strategy that describes how the proposed action will comply with the EPA groundwater protection standards is presented in Attachment 4. Site characterization activities discussed in this section include: Definition of the hydrogeologic characteristics of the environment, including hydrostratigraphy, aquifer parameters, areas of aquifer recharge and discharge, potentiometric surfaces, and groundwater velocities. Definition of background groundwater quality and comparison with the proposed EPA groundwater protection standards. Evaluation of the physical and chemical characteristics of the contaminant source and/or residual radioactive materials. Definition of existing groundwater contamination by comparison with the EPA groundwater protection standards. Description of the geochemical processes that affect the downward migration of the source contaminants at the processing site. Description of water resource utilization, including availability, current and future use and value, and alternate water supplies

  20. Thermo-stabilized, porous polyimide microspheres prepared from nanosized SiO2 templating via in situ polymerization

    Directory of Open Access Journals (Sweden)

    M. Q. Liu

    2015-01-01

    Full Text Available In this article, we addressed a feasible and versatile method of the fabrication of porous polyimide microspheres presenting excellent heat resistance. The preparation process consisted of two steps. Firstly, a novel polyimide/nano-silica composite microsphere was prepared via the self-assembly structures of poly(amic acid (PAA, precursor of PI/nanosized SiO2 blends after in situ polymerization, following the two-steps imidization. Subsequently, the encapsulated nanoparticles were etched away by hydrofluoric acid treatment, giving rise to the pores. It is found the composite structure of PI/SiO2 is a precondition of the formation of nanoporous structures, furthermore, the morphology of the resultant pore could be relatively tuned by changing the content and initial morphology of silica nano-particles trapped into PI matrix. The thermal properties of the synthesized PI porous spheres were studied, indicating that the introduction of nanopores could not effectively influence the thermal stabilities of PI microspheres. Moreover, the fabrication technique described here may be extended to other porous polymer systems.

  1. Implementation of an ex situ stabilization technique at the Sand Springs superfund site to solidify and stabilize acid tar sludges involving a quick-lime based stabilization process and innovative equipment design

    International Nuclear Information System (INIS)

    McManus, R.W.; Grajczak, P.; Wilcoxson, J.C.; Webster, S.D.

    1997-01-01

    An old refinery site was safely remediated a year before schedule and for 25% less than final engineering estimates for the stabilization remedy thanks to energetic project management and innovative design involving ex situ stabilization/solidification of acid tar sludges. A quicklime based process, Dispersion by Chemical Reaction (DCR trademark), was employed to solidify and stabilize (SS) over 103,000 cubic meters (135,000 cubic yards) of petroleum waste, mostly acidic tarry sludge. The SS process was selected over competing methods because it afforded minimal volume increase, could readily achieve Record of Decision (ROD) specified physical and chemical treatment goals, could be implemented with treatment equipment that minimized emissions, and could be performed with low reagent usage and at low cost. To ensure treatment goals were achieved and an accelerated schedule met, a custom designed and fabricated transportable treatment unit (TTU) was employed to implement the process. The treated material was visually soil-like in character, it was left in stockpiles for periods of time, and it was placed and compacted in the on site landfill using standard earth-moving equipment

  2. An in-situ X-ray absorption spectroelectrochemical study of the electroreduction of uranium ions in HCl, HNO{sub 3}, and Na{sub 2}CO{sub 3} solutions

    Energy Technology Data Exchange (ETDEWEB)

    Uehara, Akihiro; Fujii, Toshiyuki; Yamana, Hajimu [Kyoto Univ., Osaka (Japan). Div. of Nuclear Engineering Science; Okamoto, Yoshihiro [Japan Atomic Energy Agency, Ibaraki (Japan). Quantum Beam Science Directorate

    2016-04-01

    A spectroelectrochemical cell was fabricated for in-situ X-ray absorption spectroscopy (in-situ XAS). The XAS spectra of the uranium L{sub III} edge were monitored in electrolyte solutions during the electrochemical reduction. Tetravalent uranium, U{sup 4+}, in 1 mol dm{sup -3} (M) hydrochloric acid (HCl) was electrochemically prepared from hexavalent uranium, UO{sub 2}{sup 2+}, by constant current electrolysis, and the extended X-ray absorption fine structure (EXAFS) was analyzed. The concentration ratio of UO{sub 2}{sup 2+} and U{sup 4+}, which were formed via the disproportionation of pentavalent uranium, UO{sub 2}{sup +}, during the electrolysis, were calculated based on the intensity of the signal for the two axial oxygen atoms in the linear UO{sub 2}{sup 2+} unit, the U-O{sub ax}, bond that had a radial structural function. The apparent redox potential of the UO{sub 2}{sup 2+}/U{sup 4+} couple in 1 M HCl was determined based on the Nernst equation using the concentrations of UO{sub 2}{sup 2+} and U{sup 4+}. The electrode potential was shown to be close to the formal potential of the UO{sub 2}{sup 2+}/UO{sub 2}{sup +} couple as reported previously. This result indicates that the UO{sub 2}{sup +} that was formed electrochemically at the electrode disproportionated to form UO{sub 2}{sup 2+} and U{sup 4+} in the bulk solution. The in-situ XAS of UO{sub 2}{sup 2+} in 0.1 M nitric acid was also performed. The U{sup 4+} that formed was partially re-oxidized to UO{sub 2}{sup 2+} by the NO{sub 3}{sup -} present in the solution. The formation of the UO{sub 2}{sup +} carbonato complex was observed by in-situ XAS in a 1 M sodium carbonate solution during the bulk electrolysis. The edge jump of the X-ray absorption near edge structure (XANES) spectrum shifted from 17.164 to 17.163 keV, and the bond distances of U-O{sub ax} and U-O for CO{sub 3}{sup 2-} increased from 1.78 to 1.88 Aa and from 2.42 to 2.53 Aa, respectively, because of the reduction of the UO{sub 2}{sup 2

  3. In-Situ Measurements of Low Enrichment Uranium Holdup Process Gas Piping at K-25 - Paper for Waste Management Symposia 2010 East Tennessee Technology Park Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Rasmussen, B.

    2010-01-01

    This document is the final version of a paper submitted to the Waste Management Symposia, Phoenix, 2010, abstract BJC/OR-3280. The primary document from which this paper was condensed is In-Situ Measurement of Low Enrichment Uranium Holdup in Process Gas Piping at K-25 Using NaI/HMS4 Gamma Detection Systems, BJC/OR-3355. This work explores the sufficiency and limitations of the Holdup Measurement System 4 (HJVIS4) software algorithms applied to measurements of low enriched uranium holdup in gaseous diffusion process gas piping. HMS4 has been used extensively during the decommissioning and demolition project of the K-25 building for U-235 holdup quantification. The HMS4 software is an integral part of one of the primary nondestructive assay (NDA) systems which was successfully tested and qualified for holdup deposit quantification in the process gas piping of the K-25 building. The initial qualification focused on the measurement of highly enriched UO 2 F 2 deposits. The purpose of this work was to determine if that qualification could be extended to include the quantification of holdup in UO 2 F 2 deposits of lower enrichment. Sample field data are presented to provide evidence in support of the theoretical foundation. The HMS4 algorithms were investigated in detail and found to sufficiently compensate for UO 2 F 2 source self-attenuation effects, over the range of expected enrichment (4-40%), in the North and East Wings of the K-25 building. The limitations of the HMS4 algorithms were explored for a described set of conditions with respect to area source measurements of low enriched UO 2 F 2 deposits when used in conjunction with a 1 inch by 1/2 inch sodium iodide (NaI) scintillation detector. The theoretical limitations of HMS4, based on the expected conditions in the process gas system of the K-25 building, are related back to the required data quality objectives (DQO) for the NBA measurement system established for the K-25 demolition project. The combined

  4. Uranium 2000 : International symposium on the process metallurgy of uranium

    International Nuclear Information System (INIS)

    Ozberk, E.; Oliver, A.J.

    2000-01-01

    The International Symposium on the Process Metallurgy of Uranium has been organized as the thirtieth annual meeting of the Hydrometallurgy Section of the Metallurgical Society of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM). This meeting is jointly organized with the Canadian Mineral Processors Division of CIM. The proceedings are a collection of papers from fifteen countries covering the latest research, development, industrial practices and regulatory issues in uranium processing, providing a concise description of the state of this industry. Topics include: uranium industry overview; current milling operations; in-situ uranium mines and processing plants; uranium recovery and further processing; uranium leaching; uranium operations effluent water treatment; tailings disposal, water treatment and decommissioning; mine decommissioning; and international regulations and decommissioning. (author)

  5. Investigation for closedown activities in the uranium mine Zirovski vrh

    International Nuclear Information System (INIS)

    Cadez, F.; Likar, B.; Logar, Z.

    1995-01-01

    The uranium mine Zirovski vrh was temporarily shut down by order of Government of the Republic of Slovenia in the second half of the year 1990. After the Slovenian parliament passed the law on definite closing down of the uranium mine exploitation and on rehabilitation the effect of mining on the environment in July 1992 was starting to make the Programme of the Permanent Closing down of the Uranium ore Exploitation and Permanent Protection of the Environment in Uranium Mine that is in final phase. In the meantime the studies that would define necessary parameters for elaborating the projects of closure have been done. Two essential studies for the realization of closure of mine are working out: 1. Previous dewatering of the deposit by boreholes for diminishing of pollution of mine water by uranium; 2. Filling of partially collapsed stops by hydromettallurgical waste to assure permanent stability above the mine spaces. The aim of the first study is to reduce percolation of mine water through the mineralized parts of the deposit by drilling boreholes in the footwall and in the hanging wall. Pollution of mine water which outflows from the lowest tunnel in the local creek Brebovscica should be diminished. Tests of stability and lixiviation on the cubes that are made of hydrometallurgical waste are the topic of the second study. Cement and different additives are added in the cubes and testings have been made in situ. (author). 3 refs, 3 figs, 2 tabs

  6. Remedial action plan and site design for stabilization of the inactive uranium mill tailings sites at Rifle, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

    This appendix assesses the present conditions and data gathered about the two inactive uranium mill tailings sites near Rifle, Colorado, and the designated disposal site six miles north of Rifle in the area of Estes Gulch. It consolidates available engineering, radiological, geotechnical, hydrological, meteorological, and other information pertinent to the design of the Remedial Action Plan (RAP). The data characterize conditions at the mill, tailings, and disposal site so that the Remedial Action Contractor (RAC) may complete final designs for the remedial actions.

  7. Remedial action plan and site design for stabilization of the inactive uranium processing site at Naturita, Colorado

    International Nuclear Information System (INIS)

    1993-08-01

    The US Environmental Protection Agency (EPA) has established health and environmental protection regulations to correct and prevent groundwater contamination resulting from processing activities at inactive uranium milling sites (40 CFR 192). The Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978 designated responsibility to the US Department of Energy (DOE) for assessing the inactive uranium milling sites. The DOE has determined that each assessment shall include information on site characterization, a description of the proposed action, and a summary of the water resources protection strategy that describes how the proposed action will comply with the EPA groundwater protection standards. To achieve compliance with the proposed US Environmental Protection Agency (EPA) groundwater protection standards, the US Department of Energy (DOE) proposes that supplemental standards be applied at the Dry Flats disposal site because of Class III (limited use) groundwater in the uppermost aquifer (the basal sandstone of the Cretaceous Burro Canyon Formation) based on low yield. The proposed remedial action will ensure protection of human health and the environment

  8. Remedial action plan and site design for stabilization of the inactive uranium processing site at Naturita, Colorado

    International Nuclear Information System (INIS)

    1994-03-01

    The uranium processing site near Naturita, Colorado, is one of 24 inactive uranium mill sites designated to be cleaned up by the US Department of Energy (DOE) under the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), 42 USC section 7901 et seq. Part of the UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE's remedial action plan (RAP) and certify that the remedial action conducted at the site complies with the standards promulgated by the US Environmental Protection Agency (EPA). Included in the RAP is this Remedial Action Selection Report (RAS), which describes the proposed remedial action for the Naturita site. An extensive amount of data and supporting information has been generated and evaluated for this remedial action. These data and supporting information are not incorporated into this single document but are included or referenced in the supporting documents. The RAP consists of this RAS and four supporting documents or attachments. This Attachment 2, Geology Report describes the details of geologic, geomorphic, and seismic conditions at the Dry Flats disposal site

  9. Microbial bioremediation of Uranium: an overview

    International Nuclear Information System (INIS)

    Acharya, Celin

    2015-01-01

    Uranium contamination is a worldwide problem. Preventing uranium contamination in the environment is quite challenging and requires a thorough understanding of the microbiological, ecological and biogeochemical features of the contaminated sites. Bioremediation of uranium is largely dependent on reducing its bioavailability in the environment. In situ bioremediation of uranium by microbial processes has been shown to be effective for immobilizing uranium in contaminated sites. Such microbial processes are important components of biogeochemical cycles and regulate the mobility and fate of uranium in the environment. It is therefore vital to advance our understanding of the uranium-microbe interactions to develop suitable bioremediation strategies for uranium contaminated sites. This article focuses on the fundamental mechanisms adopted by various microbes to mitigate uranium toxicity which could be utilized for developing various approaches for uranium bioremediation. (author)

  10. Phase stability and oxygen non-stoichiometry of SrCo0.8Fe0.2O3-d measured by in-situ neutron diffraction

    NARCIS (Netherlands)

    McIntosh, Steven; McIntosh, S.; Vente, Jaap F.; Haije, Wim G.; Blank, David H.A.; Bouwmeester, Henricus J.M.

    2006-01-01

    The phase stability, oxygen stoichiometry and expansion properties of SrCo0.8Fe0.2O3−δ (SCF) were determined by in situ neutron diffraction between 873 and 1173 K and oxygen partial pressures of 5×10−4 to 1 atm. At a pO2 of 1 atm, SCF adopts a cubic perovskite structure, space group Pm3¯m, across

  11. On the stability of a variety of organic photovoltaic devices by IPCE and in situ IPCE analyses - the ISOS-3 inter-laboratory collaboration

    OpenAIRE

    Terán-Escobar, Gerardo; Krebs, Frederik C.; Lira-Cantú, Mónica

    2012-01-01

    This work is part of the inter-laboratory collaboration to study the stability of seven distinct sets of state-of-the-art organic photovoltaic (OPV) devices prepared by leading research laboratories. All devices have been shipped to and degraded at RISempty set-DTU up to 1830 hours in accordance with established ISOS-3 protocols under defined illumination conditions. In this work, we apply the Incident Photon-to-Electron Conversion Efficiency (IPCE) and the in situ IPCE techniques to determin...

  12. Shining a light on Jarosite: formation, alteration and stability studies using in situ experimental synchrotron and neutron techniques.

    Science.gov (United States)

    Brand, H. E. A.; Scarlett, N. V. Y.; Wilson, S. A.; Frierdich, A. J.; Grey, I. E.

    2016-12-01

    Jarosites and related minerals are critical to a range of mineral processing and research applications. They are used in the removal of iron species from smelting processes; they occur in metal bioleaching systems, and they are present in acid mine drainage environments. There has been a recent resurgence in interest in jarosites since their detection on Mars. In this context, the presence of jarosite has been recognised as a likely indicator of liquid water at the surface of Mars in the past & it is thought that their study will provide insight into the environmental history of Mars. Acid sulfate soils cover large areas of the Australian coastline and are likely to be a major constituent of the Martian environment. The oxidation of acid sulfate soils, coupled with potential release of heavy metals and acidic groundwaters, can have serious consequences for fragile ecosystems. Understanding these sediments will provide insight into the biogeochemical processes that affect the lifetimes of transient mineral species on Earth, and may be used to better understand soil acidification, contaminant mobility at sites affected by acid and metalliferous drainage, and even constrain past weathering and putative biosignatures on Mars. Knowledge of the behaviour of jarosite minerals under the actual conditions that they are found in is crucial to understanding their potential environmental impacts on both Earth and Mars. To this end, we are engaged in a program to study the formation, stability and alteration of natural and synthetic jarosite minerals using a complementary suite of in situ synchrotron and neutron techniques. There are 3 sections to this work that will introduce the experimental techniques and sample environments that make these measurements possible: Studying the nucleation and growth of jarosites under laboratory conditions. The experimentation consisted of time-resolved synchrotron small angle X-ray scattering and X-ray diffraction. Studying the stability of

  13. In-situ assaying for uranium in rock formations and method of undirectly monitoring the output of a pulsed neutron source

    International Nuclear Information System (INIS)

    Givens, W.W.; Caldwell, R.L.; Mills, W.R. Jr.

    1975-01-01

    A description is given of a method of assaying for uranium in the formations traversed by a borehole, which comprises: 1) locating a pulsed neutron source and a neutron detector in a borehole at the level of a formation of interest suspected of containing uranium; 2) operating the neutron source cyclically with the time between each neutron burst being sufficient to allow neutrons from the source to disappear but being long enough to allow the delayed neutrons resulting from the neutron fission of uranium to appear at the detector; 3) detecting neutrons with the detector, as a result of the irradiation of the formations with the neutrons from the source, and obtaining measurements of the quantity of neutrons detected between neutron bursts only at a time period when neutrons from the source have disappeared but, while delayed fission neutrons from uranium may be emitted. (author)

  14. Safety, efficacy, predictability and stability of laser in situ keratomileusis (LASIK) with a 1000-Hz scanning spot excimer laser.

    Science.gov (United States)

    Khoramnia, Ramin; Salgado, Josefina P; Wuellner, Christian; Donitzky, Christof; Lohmann, Chris P; Winkler von Mohrenfels, Christoph

    2012-09-01

    To evaluate the safety, efficacy, predictability and stability of laser in situ keratomileusis (LASIK) with a 1000-Hz scanning spot excimer laser (Concept System 1000; WaveLight GmbH, Erlangen, Germany). LASIK was performed on twenty eyes with myopia or myopic astigmatism (mean spherical equivalent refraction: -3.97±1.72 dioptres (D); mean cylinder: -0.84±0.77 D) using a microkeratome for flap creation and the Concept System 1000 for photoablation. Patients were examined preoperatively as well as 1, 3 and 6 months after the treatment. Manifest sphere and cylinder, uncorrected (UCDVA) and best corrected (BCDVA) distance visual acuity, corneal topography and pachymetry were analysed. We observed no adverse events that might have been associated with the use of a repetition rate of 1000 Hz. All eyes maintained or had improved BCDVA at 6 months after treatment when compared to preoperative values. Six months after LASIK, UCDVA was 20/20 or better in 85% and 20/25 or better in 100% of the eyes. The spherical equivalent refraction was within ±0.50 D in 95% of the eyes at 6 months after surgery. The refraction stayed stable over time; 95% of the eyes changedLASIK with the prototype 1000-Hz excimer laser was safe, efficient and predictable. The postoperative refraction was stable over time. There were no specific clinical side-effects that might be associated with the use of such a high repetition rate. © 2011 The Authors. Acta Ophthalmologica © 2011 Acta Ophthalmologica Scandinavica Foundation.

  15. Enhanced permanganate in situ chemical oxidation through MnO2 particle stabilization: evaluation in 1-D transport systems.

    Science.gov (United States)

    Crimi, Michelle; Quickel, Mark; Ko, Saebom

    2009-02-27

    In situ chemical oxidation using permanganate is an increasingly employed approach to organic contaminant remediation at hazardous waste sites. Manganese dioxide (MnO2) particles form as a by-product of the reaction of permanganate with contaminants and naturally-reduced subsurface materials. These particles are of interest because they have the potential to deposit in the subsurface and impact the flow regime in/around permanganate injection, including the well screen, filter pack, and the surrounding subsurface formation. Control of these particles can allow for improved oxidant injection and transport, and contact between the oxidant and contaminants of concern. Sodium hexametaphosphate (HMP) has previously been identified as a promising aid to stabilize MnO2 in solution when included in the oxidizing solution, increasing the potential to inhibit particle deposition and impact subsurface flow. The goal of the experimental studies described herein was to investigate the ability of HMP to prevent particle deposition in transport studies using four different types of porous media. Permanganate was delivered to a contaminant source zone (trichloroethylene) located within four different media types with variations in sand, clay, organic carbon, and iron oxides (as goethite) content. Deposition of MnO2 within the columns was quantified with distance from the source zone. Experiments were repeated in replicate columns with the inclusion of HMP directly with the oxidant delivery solution, and MnO2 deposition was again quantified. While total MnO2 deposition within the 60 cm columns did not change significantly with the addition of HMP, deposition within the contaminant source zone decreased by 25-85%, depending on the specific media type. The greatest differences in deposition were observed in the goethite-containing and clay-containing columns. Columns containing these two media types experienced completely plugged flow in the oxidant-only delivery systems; however

  16. In situ stabilization of trace metals in a copper-contaminated soil using P-spiked Linz-Donawitz slag.

    Science.gov (United States)

    Negim, Osama; Mench, Michel; Bes, Clémence; Motelica-Heino, Mikael; Amin, Fouad; Huneau, Frédéric; Le Coustumer, Philippe

    2012-03-01

    A former wood exploitation revealing high Cu and As concentration of the soils served as a case study for assisted phytoextraction. P-spiked Linz-Donawitz (LD) slag was used as a soil additive to improve physico-chemical soil properties and in situ stabilize Cu and other trace metals in a sandy Cu-contaminated soil (630 mg kg⁻¹ soil). The LD slag was incorporated into the contaminated soil to consist four treatments: 0% (T1), 1% (T2), 2% (T3), and 4% (T4). A similar uncontaminated soil was used as a control (CTRL). After a 1-month reaction period, potted soils were used for a 2-week growth experiment with dwarf beans. Soil pH increased with the incorporation rate of LD slag. Similarly the soil electrical conductivity (EC, in millisiemens per centimetre) is ameliorated. Bean plants grown on the untreated soil (T1) showed a high phytotoxicity. All incorporation rates of LD slag increased the root and shoot dry weight yields compared to the T1. The foliar Ca concentration of beans was enhanced for all LD slag-amended soil, while the foliar Mg, K, and P concentrations were not increased. Foliar Cu, Zn, and Cr concentrations of beans decreased with the LD slag incorporation rate. P-spiked LD slag incorporation into polluted soil allow the bean growth and foliar Ca concentration, but also to reduce foliar Cu concentration below its upper critical value avoiding an excessive soil EC and Zn deficiency. This dual effect can be of interest for soil remediation at larger scale.

  17. Uranium industry annual 1993

    International Nuclear Information System (INIS)

    1994-09-01

    Uranium production in the United States has declined dramatically from a peak of 43.7 million pounds U 3 O 8 (16.8 thousand metric tons uranium (U)) in 1980 to 3.1 million pounds U 3 O 8 (1.2 thousand metric tons U) in 1993. This decline is attributed to the world uranium market experiencing oversupply and intense competition. Large inventories of uranium accumulated when optimistic forecasts for growth in nuclear power generation were not realized. The other factor which is affecting U.S. uranium production is that some other countries, notably Australia and Canada, possess higher quality uranium reserves that can be mined at lower costs than those of the United States. Realizing its competitive advantage, Canada was the world's largest producer in 1993 with an output of 23.9 million pounds U 3 O 8 (9.2 thousand metric tons U). The U.S. uranium industry, responding to over a decade of declining market prices, has downsized and adopted less costly and more efficient production methods. The main result has been a suspension of production from conventional mines and mills. Since mid-1992, only nonconventional production facilities, chiefly in situ leach (ISL) mining and byproduct recovery, have operated in the United States. In contrast, nonconventional sources provided only 13 percent of the uranium produced in 1980. ISL mining has developed into the most cost efficient and environmentally acceptable method for producing uranium in the United States. The process, also known as solution mining, differs from conventional mining in that solutions are used to recover uranium from the ground without excavating the ore and generating associated solid waste. This article describes the current ISL Yang technology and its regulatory approval process, and provides an analysis of the factors favoring ISL mining over conventional methods in a declining uranium market

  18. Uranium industry annual 1993

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    Uranium production in the United States has declined dramatically from a peak of 43.7 million pounds U{sub 3}O{sub 8} (16.8 thousand metric tons uranium (U)) in 1980 to 3.1 million pounds U{sub 3}O{sub 8} (1.2 thousand metric tons U) in 1993. This decline is attributed to the world uranium market experiencing oversupply and intense competition. Large inventories of uranium accumulated when optimistic forecasts for growth in nuclear power generation were not realized. The other factor which is affecting U.S. uranium production is that some other countries, notably Australia and Canada, possess higher quality uranium reserves that can be mined at lower costs than those of the United States. Realizing its competitive advantage, Canada was the world`s largest producer in 1993 with an output of 23.9 million pounds U{sub 3}O{sub 8} (9.2 thousand metric tons U). The U.S. uranium industry, responding to over a decade of declining market prices, has downsized and adopted less costly and more efficient production methods. The main result has been a suspension of production from conventional mines and mills. Since mid-1992, only nonconventional production facilities, chiefly in situ leach (ISL) mining and byproduct recovery, have operated in the United States. In contrast, nonconventional sources provided only 13 percent of the uranium produced in 1980. ISL mining has developed into the most cost efficient and environmentally acceptable method for producing uranium in the United States. The process, also known as solution mining, differs from conventional mining in that solutions are used to recover uranium from the ground without excavating the ore and generating associated solid waste. This article describes the current ISL Yang technology and its regulatory approval process, and provides an analysis of the factors favoring ISL mining over conventional methods in a declining uranium market.

  19. In situ effects of metal contamination from former uranium mining sites on the health of the three-spined stickleback (Gasterosteus aculeatus, L.).

    Science.gov (United States)

    Le Guernic, Antoine; Sanchez, Wilfried; Bado-Nilles, Anne; Palluel, Olivier; Turies, Cyril; Chadili, Edith; Cavalié, Isabelle; Delahaut, Laurence; Adam-Guillermin, Christelle; Porcher, Jean-Marc; Geffard, Alain; Betoulle, Stéphane; Gagnaire, Béatrice

    2016-08-01

    Human activities have led to increased levels of various pollutants including metals in aquatic ecosystems. Increase of metallic concentrations in aquatic environments represents a potential risk to exposed organisms, including fish. The aim of this study was to characterize the environmental risk to fish health linked to a polymetallic contamination from former uranium mines in France. This contamination is characterized by metals naturally present in the areas (manganese and iron), uranium, and metals (aluminum and barium) added to precipitate uranium and its decay products. Effects from mine releases in two contaminated ponds (Pontabrier for Haute-Vienne Department and Saint-Pierre for Cantal Department) were compared to those assessed at four other ponds outside the influence of mine tailings (two reference ponds/department). In this way, 360 adult three-spined sticklebacks (Gasterosteus aculeatus) were caged for 28 days in these six ponds before biomarker analyses (immune system, antioxidant system, biometry, histology, DNA integrity, etc.). Ponds receiving uranium mine tailings presented higher concentrations of uranium, manganese and aluminum, especially for the Haute-Vienne Department. This uranium contamination could explain the higher bioaccumulation of this metal in fish caged in Pontabrier and Saint-Pierre Ponds. In the same way, many fish biomarkers (antioxidant and immune systems, acetylcholinesterase activity and biometric parameters) were impacted by this environmental exposure to mine tailings. This study shows the interest of caging and the use of a multi-biomarker approach in the study of a complex metallic contamination.

  20. Uranium: Memories of the Little Big Horn

    International Nuclear Information System (INIS)

    White, G. Jr.

    1985-01-01

    In this work the author discusses the future of the uranium industry. The author believes that uranium prices are unlikely to rise to a level that predicates the rebirth of the uranium industry, and doubts that U.S. production of uranium will exceed 30 to 35 percent of U.S. requirements. The author doubts that the U.S. government will take any action toward protecting the U.S. uranium production industry, but he does believe that a U.S. uranium production industry will survive and include in-situ and by product producers and producers with higher grades and rigorous cost control

  1. Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Gunnison, Colorado

    International Nuclear Information System (INIS)

    1992-10-01

    To achieve compliance with the proposed US Environmental Protection Agency (EPA) groundwater protection standards the US Department of Energy (DOE) proposes to meet background concentrations or the EPA maximum concentration limits (MCLS) for hazardous constituents in groundwater in the uppermost aquifer at the point of compliance (POC) at the Gunnison Uranium Mill Tailings Remedial Action (UMTRA) Project disposal site near Gunnison, Colorado. The proposed remedial action will ensure protection of human health and the environment. A summary of the principal features of the water resources protection strategy for the Gunnison disposal site is included in this report

  2. Remedial action plan and site design for stabilization of the inactive uranium mill tailings site at Lakeview, Oregon: Volume 1, Text and appendices A through D

    International Nuclear Information System (INIS)

    Chernoff, A.R.

    1992-07-01

    The Lakeview inactive uranium processing site is in Lake County, Oregon, approximately one mile northwest of the town of Lakeview, sixteen miles north of the California-Oregon border, and 96 miles east of Klamath Falls. The total designated site covers an area of 258 acres consisting of a tailings pile (30 acres). seven evaporation ponds (69 acres), the mill buildings, and related structures. The mill buildings and other structures have been decontaminated and are currently being used by Goose Lake Lumber Company. The tailings pile at the processing site was originally stabilized by Atlantic Richfield with an earthen cover 18--24 inches thick. The average depth of the tailings, including the cover, varied from six to eight feet. There were estimated to be 662,000 cubic yards of tailings, windblown contaminated materials, and vicinity property materials. During remedial action under the Uranium Mill Tailings Remedial Action (UMTRA) Project, approximately 264,000 cubic yards of additional contaminated materials were identified from excavations required to remove thorium- and arsenic-contaminated soils. The remedial action for the Lakeview site consisted of the cleanup, relocation, consolidation, and stabilization of all residual radioactive materials and thorium- and arsenic-contaminated materials in a partially below-grade disposal cell at a location approximately seven miles northwest of the tailings site, identified as the Collins Ranch site. A cover, including a radon/infiltration barrier and rock layer for protection from erosion, was Placed on top of the tailings. A rock-soil matrix covers the topslope and provides a growth medium for vegetation. The US Department of Energy (DOE) will retain the license and surveillance and maintenance responsibilities for the final restricted site of 13 acres

  3. Remedial action plan and site design for stabilization of the inactive uranium mill tailings sites at Rifle, Colorado: Final report

    International Nuclear Information System (INIS)

    1990-02-01

    This radiologic characterization of tho two inactive uranium millsites at Rifle, Colorado, was conducted by Bendix Field Engineering Corporation (Bendix) for the US Department of Energy (DOE), Grand Junction Projects Office, in accord with a Statement of Work prepared by the DOE Uranium Mill Tailings Remedial Action (UMTRA) Project Technical Assistance Contractor, Jacobs Engineering Group, Inc. (Jacobs). The purpose of this project is to define the extent of radioactive contamination at the Rifle sites that exceeds US Environmental Protection Agency, (EPA) standards for UMTRA sites. The data presented in this report are required for characterization of the areas adjacent to the tailings piles and for the subsequent design of cleanup activities. An orientation visit to the study area was conducted on 31 July--1 August 1984, in conjunction with Jacobs, to determine the approximate extent of contaminated area surrounding tho piles. During that visit, survey control points were located and baselines were defined from which survey grids would later be established; drilling requirements were assessed; and radiologic and geochemical data were collected for use in planning the radiologic fieldwork. The information gained from this visit was used by Jacobs, with cooperation by Bendix, to determine the scope of work required for the radiologic characterization of the Rifle sites. Fieldwork at Rifle was conducted from 1 October through 16 November 1984

  4. Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Gunnison, Colorado

    International Nuclear Information System (INIS)

    1992-10-01

    Diffusion coefficients for radon gas in earthen materials are required to design suitable radon-barrier covers for uranium tailings impoundments and other materials that emit radon gas. Many early measurements of radon diffusion coefficients relied on the differences in steady-state radon fluxes measured from radon source before and after installation of a cover layer of the material being tested. More recent measurements have utilized the small-sample transient (SST) technique for greater control on moistures and densities of the test soils, greater measurement precision, and reduced testing time and costs. Several of the project sites for the US Department of Energy's Uranium Mill Tailings Remedial Action (UMTRA) Program contain radiologically contaminated subsurface material composed predominantly of cobbles, gravels andsands. Since remedial action designs require radon diffusion coefficients for the source materials as well as the cover materials, these cobbly and gravelly materials also must be tested. This report contains the following information: a description of the test materials used and the methods developed to conduct the SST radon diffusion measurements on cobbly soils; the protocol for conducting radon diffusion tests oncobbly soils; the results of measurements on the test samples; and modifications to the FITS computer code for analyzing the time-dependent radon diffusion data

  5. Depleted uranium

    International Nuclear Information System (INIS)

    Huffer, E.; Nifenecker, H.

    2001-02-01

    This document deals with the physical, chemical and radiological properties of the depleted uranium. What is the depleted uranium? Why do the military use depleted uranium and what are the risk for the health? (A.L.B.)

  6. Impact of In Situ Stress Distribution Characteristics on Jointed Surrounding Rock Mass Stability of an Underground Cavern near a Hillslope Surface

    Directory of Open Access Journals (Sweden)

    Bangxiang Li

    2017-01-01

    Full Text Available In this paper, a series of numerical simulations are performed to analyze the in situ stress distribution characteristics of the rock mass near different slope angles hillslope surfaces, which are subjected to the vertical gravity stress and different horizontal lateral stresses and the influence which the in situ stress distribution characteristics of 45° hillslope to the integral stability of surrounding rock mass when an underground cavern is excavated considering three different horizontal distances from the underground cavern to the slope surface. It can be concluded from the numerical results that different slope angles and horizontal lateral stresses have a strong impact on the in situ stress distribution and the integral surrounding rock mass stability of the underground cavern when the horizontal distance from the underground cavern to the slope surface is approximately 100 m to 200 m. The relevant results would provide some important constructive suggestions to the engineering site selection and optimization of large-scale underground caverns in hydropower stations.

  7. Remedial action and site design for stabilization of the inactive uranium mill tailings sites at Slick Rock, Colorado

    International Nuclear Information System (INIS)

    1993-07-01

    This report presents geologic considerations that are pertinent to the Remedial Action Plan for Slick Rock mill tailings. Topics covered include regional geology, site geology, geologic stability, and geologic suitability

  8. Combining in situ chemical oxidation, stabilization, and anaerobic bioremediation in a single application to reduce contaminant mass and leachability in soil.

    Science.gov (United States)

    Cassidy, Daniel P; Srivastava, Vipul J; Dombrowski, Frank J; Lingle, James W

    2015-10-30

    Laboratory batch reactors were maintained for 32 weeks to test the potential for an in situ remedy that combines chemical oxidation, stabilization, and anaerobic bioremediation in a single application to treat soil from a manufactured gas plant, contaminated with polycyclic aromatic hydrocarbons (PAH) and benzene, toluene, ethylbenzene, and xylenes (BTEX). Portland cement and slaked lime were used to activate the persulfate and to stabilize/encapsulate the contaminants that were not chemically oxidized. Native sulfate-reducing bacteria degraded residual contaminants using the sulfate left after persulfate activation. The ability of the combined remedy to reduce contaminant mass and leachability was compared with NaOH-activated persulfate, stabilization, and sulfate-reducing bioremediation as stand-alone technologies. The stabilization amendments increased pH and temperature sufficiently to activate the persulfate within 1 week. Activation with both stabilization amendments and NaOH removed between 55% and 70% of PAH and BTEX. However, combined persulfate and stabilization significantly reduced the leachability of residual BTEX and PAH compared with NaOH activation. Sulfide, 2-naphthoic acid, and the abundance of subunit A of the dissimilatory sulfite reductase gene (dsrA) were used to monitor native sulfate-reducing bacteria, which were negatively impacted by activated persulfate, but recovered completely within weeks. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Liquefaction of uranium tailings

    International Nuclear Information System (INIS)

    1992-02-01

    Numerical methods for assessing the liquefaction potential of soils are reviewed with a view to their application to uranium tailings. The method can be divided into two categories: total stress analysis, where changes in pore pressure are not considered in the soil model, and effective stress analysis, where changes in pore pressure are included in the soil model. Effective stress analysis is more realistic, but few computer programs exist for such analysis in two or three dimensions. A simple linearized, two-dimensional, finite element effective stress analysis which incorporates volumetric compaction due to shear motion is described and implemented. The new program is applied to the assessment of liquefaction potential of tailings in the Quirke Mine tailings area near Elliot Lake, Ontario. The results are compared with those of a total stress analysis. Both analyses indicate liquefaction would occur if a magnitude 6.0 earthquake were to occur near the area. However, the extent of liquefaction predicted by the effective stress analysis is much less than that predicted by the total stress analysis. The results of both methods are sensitive to assumed material properties and to the method used to determine the cyclic shear strength of the tailings. Further analysis, incorporating more in situ and/or laboratory data, is recommended before conclusions can be made concerning the dynamic stability of these tailings

  10. Remedial action plan and site design for stabilization of the inactive uranium mill tailings sites at Slick Rock, Colorado

    International Nuclear Information System (INIS)

    1993-07-01

    The Slick Rock uranium mill tailings sites are located near the small town of Slick Rock, in San Miguel County, Colorado. There are two designated UMTRA sites at Slick Rock, the Union Carbide (UC) site and the North Continent (NC) site. Both sites are adjacent to the Dolores River. The UC site is approximately 1 mile (mi) [2 kilometers (km)] downstream of the NC site. Contaminated materials cover an estimated 55 acres (ac) [22 hectares (ha)] at the UC site and 12 ac (4.9 ha) at the NC site. The sites contain former mill building concrete foundations, tailings piles, demolition debris, and areas contaminated by windblown and waterborne radioactive materials. The total estimated volume of contaminated materials is approximately 620, 000 cubic yards (yd 3 ) [470,000 cubic meters (m 3 )]. In addition to the contamination at the two processing site areas, four vicinity properties were contaminated. Contamination associated with the UC and NC sites has leached into groundwater

  11. The sorption of uranium(VI) and neptunium(V) onto surfaces of selected metal oxides and alumosilicates studied by in situ vibrational spectroscopy

    International Nuclear Information System (INIS)

    Mueller, Katharina

    2010-05-01

    The migration behavior of actinides and other radioactive contaminants in the environment is controlled by prominent molecular phenomena such as hydrolysis and complexation reactions in aqueous solutions as well as the diffusion and sorption onto minerals present along groundwater flow paths. These reactions significantly influence the mobility and bioavailability of the metal ions in the environment, in particular at liquid-solid interfaces. Hence, for the assessment of migration processes the knowledge of the mechanisms occurring at interfaces is crucial. The required structural information can be obtained using various spectroscopic techniques. In the present study, the speciation of uranium(VI) and neptunium(V) at environmentally relevant mineral-water interfaces of oxides of titania, alumina, silica, zinc, and alumosilicates has been investigated by the application of attenuated total reflection Fouriertransform infrared (ATR FT-IR) spectroscopy. Moreover, the distribution of the hydrolysis products in micromolar aqueous solutions of U(VI) and Np(V/VI) at ambient atmosphere has been characterized for the first time, by a combination of ATR FT-IR spectroscopy, near infrared (NIR) absorption spectroscopy, and speciation modeling applying updated thermodynamic databases. From the infrared spectra, a significant change of the U(VI) speciation is derived upon lowering the U(VI) concentration from the milli- to the micromolar range, strongly suggesting the dominance of monomeric U(VI) hydrolysis products in the micromolar solutions. In contradiction to the predicted speciation, monomeric hydroxo species are already present at pH ≥ 2.5 and become dominant at pH 3. At higher pH levels (> 6), a complex speciation is evidenced including carbonate containing complexes. For the first time, spectroscopic results of Np(VI) hydrolysis reactions are provided in the submillimolar concentration range and at pH values up to 5.3, and they are comparatively discussed with U

  12. Influence of in situ synthesized TiC on thermal stability and corrosion behavior of Zr60Cu10Al15Ni15 amorphous composites

    International Nuclear Information System (INIS)

    Geng, Jiwei; Teng, Xinying; Zhou, Guorong; Leng, Jinfeng; Zhao, Degang

    2014-01-01

    In situ synthesized TiC particles were prepared by a thermal explosion method. Adding “in situ synthesized” TiC into Zr 60 Cu 10 Al 15 Ni 15 glass matrix to obtain amorphous matrix composites was achieved. The corrosion behavior of Zr 60 Cu 10 Al 15 Ni 15 amorphous composites was evaluated using potentiodynamic polarization measurements in 3.5 wt% NaCl solution at room temperature. The results show that the microhardness and thermal stability are improved apparently, while the TiC (≤0.6 wt%) does not significantly affect the supercooled liquid behavior. Moreover, the corrosion resistance is improved apparently because the nanocrystals accelerate the diffusion of passive elements for faster formation of the protective passive film at nanocrystals/amorphous interfaces. However, when the TiC content is more than 0.6 wt%, both glass forming ability and corrosion resistance are reduced significantly

  13. On the stability of a variety of organic photovoltaic devices by IPCE and in situ IPCE analyses--the ISOS-3 inter-laboratory collaboration.

    Science.gov (United States)

    Teran-Escobar, Gerardo; Tanenbaum, David M; Voroshazi, Eszter; Hermenau, Martin; Norrman, Kion; Lloyd, Matthew T; Galagan, Yulia; Zimmermann, Birger; Hösel, Markus; Dam, Henrik F; Jørgensen, Mikkel; Gevorgyan, Suren; Kudret, Suleyman; Maes, Wouter; Lutsen, Laurence; Vanderzande, Dirk; Würfel, Uli; Andriessen, Ronn; Rösch, Roland; Hoppe, Harald; Rivaton, Agnès; Uzunoğlu, Gülşah Y; Germack, David; Andreasen, Birgitta; Madsen, Morten V; Bundgaard, Eva; Krebs, Frederik C; Lira-Cantu, Monica

    2012-09-07

    This work is part of the inter-laboratory collaboration to study the stability of seven distinct sets of state-of-the-art organic photovoltaic (OPV) devices prepared by leading research laboratories. All devices have been shipped to and degraded at RISØ-DTU up to 1830 hours in accordance with established ISOS-3 protocols under defined illumination conditions. In this work, we apply the Incident Photon-to-Electron Conversion Efficiency (IPCE) and the in situ IPCE techniques to determine the relation between solar cell performance and solar cell stability. Different ageing conditions were considered: accelerated full sun simulation, low level indoor fluorescent lighting and dark storage. The devices were also monitored under conditions of ambient and inert (N(2)) atmospheres, which allows for the identification of the solar cell materials more susceptible to degradation by ambient air (oxygen and moisture). The different OPVs configurations permitted the study of the intrinsic stability of the devices depending on: two different ITO-replacement alternatives, two different hole extraction layers (PEDOT:PSS and MoO(3)), and two different P3HT-based polymers. The response of un-encapsulated devices to ambient atmosphere offered insight into the importance of moisture in solar cell performance. Our results demonstrate that the IPCE and the in situ IPCE techniques are valuable analytical methods to understand device degradation and solar cell lifetime.

  14. Testing of a uranium downhole logging system to measure in-situ plutonium concentrations in sediments. [216-Z-1A crib

    Energy Technology Data Exchange (ETDEWEB)

    Kasper, R.B.; Kay, M.A.; Bruns, L.E.; Stokes, J.A.; Steinman, D.K.; Adams, J.

    1980-11-01

    A prototype urainium borehole logging system, developed for uranium exploration, was modified for Pu assay and testing at the site. It uses the delayed fission neutron (DFN) method. It was tested in a retired Pu facility, the 216-Z-1A Crib. General agreement between laboratory determined Pu concentrations in sediment samples and neutron flux measurements was found for the relative distribution with depth.

  15. Trace Metals in Groundwater and the Vadose Zone Calcite: In Situ Containment and Stabilization of Strontium-90 and Other Divalent Metals and Radionuclides at Arid West DOE

    International Nuclear Information System (INIS)

    Smith, Robert W.

    2004-01-01

    Radionuclide and metal contaminants such as strontium-90 are present beneath U.S. Department of Energy (DOE) lands in both the groundwater (e.g., 100-N area at Hanford, WA) and vadose zone (e.g., Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory). In situ containment and stabilization of these contaminants is a cost-effective treatment strategy. However, implementing in situ containment and stabilization approaches requires definition of the mechanisms that control contaminant sequestration. We are investigating the in situ immobilization of radionuclides or contaminant metals (e.g., strontium-90) by their facilitated co-precipitation with calcium carbonate in groundwater and vadose zone systems. Our facilitated approach, shown schematically in Figure 1, relies upon the hydrolysis of introduced urea to cause the acceleration of calcium carbonate precipitation (and trace metal co-precipitation) by increasing pH and alkalinity. Subsurface urea hydrolysis is catalyzed by the urease enzyme, which may be either introduced with the urea or produced in situ by ubiquitous subsurface urea hydrolyzing microorganisms. Because the precipitation process tends to be irreversible and many western aquifers are saturated with respect to calcite, the co-precipitated metals and radionuclides will be effectively removed from the aqueous phase over the long-term. Another advantage of the ureolysis approach is that the ammonium ions produced by the reaction can exchange with radionuclides sorbed to subsurface minerals, thereby enhancing the availability of the radionuclides for re-capture in a more stable solid phase (co-precipitation rather than adsorption)

  16. Uranium conversion

    International Nuclear Information System (INIS)

    Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina

    2006-03-01

    FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF 6 and UF 4 are present require equipment that is made of corrosion resistant material

  17. Uranium resources in New Mexico

    International Nuclear Information System (INIS)

    McLemore, V.T.; Chenoweth, W.L.

    1989-01-01

    For nearly three decades (1951-1980), the Grants uranium district in northwestern New Mexico produced more uranium than any other district in the world. The most important host rocks containing economic uranium deposits in New Mexico are sandstones within the Jurassic Morrison Formation. Approximately 334,506,000 lb of U 3 O 8 were produced from this unit from 1948 through 1987, accounting for 38% of the total uranium production from the US. All of the economic reserves and most of the resources in New Mexico occur in the Morrison Formation. Uranium deposits also occur in sandstones of Paleozoic, Triassic, Cretaceous, Tertiary, and Quaternary formations; however, only 468,680 lb of U 3 O 8 or 0.14% of the total production from New Mexico have been produced from these deposits. Some of these deposits may have a high resource potential. In contrast, almost 6.7 million lb of U 3 O 8 have been produced from uranium deposits in the Todilto Limestone of the Wanakah Formation (Jurassic), but potential for finding additional economic uranium deposits in the near future is low. Other uranium deposits in New Mexico include those in other sedimentary rocks, vein-type uranium deposits, and disseminated magmatic, pegmatitic, and contact metasomatic uranium deposits in igneous and metamorphic rocks. Production from these deposits have been insignificant (less than 0.08% of the total production from New Mexico), but there could be potential for medium to high-grade, medium-sized uranium deposits in some areas. Total uranium production from New Mexico from 1948 to 1987 amounts to approximately 341,808,000 lb of U 3 O 8 . New Mexico has significant uranium reserves and resources. Future development of these deposits will depend upon an increase in price for uranium and lowering of production costs, perhaps by in-situ leaching techniques

  18. Uranium exploration

    International Nuclear Information System (INIS)

    De Voto, R.H.

    1984-01-01

    This paper is a review of the methodology and technology that are currently being used in varying degrees in uranium exploration activities worldwide. Since uranium is ubiquitous and occurs in trace amounts (0.2 to 5 ppm) in virtually all rocks of the crust of the earth, exploration for uranium is essentially the search of geologic environments in which geologic processes have produced unusual concentrations of uranium. Since the level of concentration of uranium of economic interest is dependent on the present and future price of uranium, it is appropriate here to review briefly the economic realities of uranium-fueled power generation. (author)

  19. 75 FR 62153 - Notice of the Nuclear Regulatory Commission Issuance of Materials License SUA-1596 for Uranium...

    Science.gov (United States)

    2010-10-07

    ... Commission Issuance of Materials License SUA-1596 for Uranium One Americas, Inc. Moore Ranch In Situ Recovery.... SUPPLEMENTARY INFORMATION: The Nuclear Regulatory Commission (NRC) has issued a license to Uranium One Americas, Inc. (Uranium One) for its Moore Ranch uranium in situ recovery (ISR) facility in Campbell County...

  20. In situ measurement of the effect of LiOH on the stability of zircaloy-2 surface film in PWR water

    International Nuclear Information System (INIS)

    Saario, T.; Taehtinen, S.

    1997-01-01

    Surface films on the metals play a major role in corrosion assisted cracking. A new method called Contact Electric Resistance (CER) method has been recently developed for in situ measurement of the electric resistance of surface films in high temperature and high pressure environments. The technique has been used to determine in situ the electric resistance of films on metals when in contact with water and dissolved anions, during formation and destruction of oxides and hydrides and during electroplating of metals. Electric resistance data can be measured with a frequency of the order of one hertz, which makes it possible to investigate in situ the kinetics of surface film related processes which are dependent on the environment, temperature, pH and electrochemical potential. This paper presents the results of the CER investigation on the effects of LiOH on the stability of Zircaloy-2 surface film in water with 2000 ppm H 3 BO 3 . At 300 deg. C the LiOH concentrations higher than 10 -2 M (roughly 70 ppm of Li + ) were found to markedly reduce the electric resistance of the Zircaloy-2 surface film during a test period of less than two hours. The decrease of the film resistance is very abrupt, possibly indicating a phase transformation. Moreover, the advantages of the CER technique over the other competing techniques which rely on the measurement of current are discussed. (author)

  1. In situ measurement of the effect of LiOH on the stability of zircaloy-2 surface film in PWR water

    Energy Technology Data Exchange (ETDEWEB)

    Saario, T; Taehtinen, S [Technical Research Centre of Finland, Espoo (Finland)

    1997-02-01

    Surface films on the metals play a major role in corrosion assisted cracking. A new method called Contact Electric Resistance (CER) method has been recently developed for in situ measurement of the electric resistance of surface films in high temperature and high pressure environments. The technique has been used to determine in situ the electric resistance of films on metals when in contact with water and dissolved anions, during formation and destruction of oxides and hydrides and during electroplating of metals. Electric resistance data can be measured with a frequency of the order of one hertz, which makes it possible to investigate in situ the kinetics of surface film related processes which are dependent on the environment, temperature, pH and electrochemical potential. This paper presents the results of the CER investigation on the effects of LiOH on the stability of Zircaloy-2 surface film in water with 2000 ppm H{sub 3}BO{sub 3}. At 300 deg. C the LiOH concentrations higher than 10{sup -2} M (roughly 70 ppm of Li{sup +}) were found to markedly reduce the electric resistance of the Zircaloy-2 surface film during a test period of less than two hours. The decrease of the film resistance is very abrupt, possibly indicating a phase transformation. Moreover, the advantages of the CER technique over the other competing techniques which rely on the measurement of current are discussed. (author).

  2. Uranium recovery research sponsored by the Nuclear Regulatory Commission at Pacific Northwest Laboratory. Annual progress report, May 1982-May 1983

    International Nuclear Information System (INIS)

    Foley, M.G.; Opitz, B.E.; Deutsch, W.J.

    1983-06-01

    Pacific Northwest Laboratory (PNL) is currently conducting research for the US Nuclear Regulatory Commission (NRC) on uranium recovery process wastes for both active and inactive operations. NRC-sponsored uranium recovery research at PNL is focused on NRC regulatory responsibilities for uranium-recovery operations: license active milling and in situ extraction operations; concur on the acceptability of DOE remedial-action plans for inactive sites; and license DOE to maintain inactive sites following remedial actions. PNL's program consists of four coordinated projects comprised of a program management task and nine research tasks that address the critical technical and safety issues for uranium recovery. Specifically, the projects endeavor to find and evaluate methods to: prevent erosion of tailings piles and prevent radon release from tailings piles; evaluate the effectiveness of interim stabilization techniques to prevent wind erosion and transport of dry tailings from active piles; estimate the dewatering and consolidation behavior of slurried tailings to promote early cover placement; design a cover-protection system to prevent erosion of the cover by expected environmental stresses; reduce seepage into ground water and prevent ground-water degradation; control solution movement and reaction with ground water in in-situ extraction operations; evaluate natural and induced restoration of ground water in in-situ extraction operations; and monitor releases to the environment from uranium recovery facilities

  3. Uranium recovery research sponsored by the Nuclear Regulatory Commission at Pacific Northwest Laboratory. Annual progress report, May 1982-May 1983

    Energy Technology Data Exchange (ETDEWEB)

    Foley, M.G.; Opitz, B.E.; Deutsch, W.J.; Peterson, S.R.; Gee, G.W.; Serne, R.J.; Hartley, J.N.; Thomas, V.W.; Kalkwarf, D.R.; Walters, W.H.

    1983-06-01

    Pacific Northwest Laboratory (PNL) is currently conducting research for the US Nuclear Regulatory Commission (NRC) on uranium recovery process wastes for both active and inactive operations. NRC-sponsored uranium recovery research at PNL is focused on NRC regulatory responsibilities for uranium-recovery operations: license active milling and in situ extraction operations; concur on the acceptability of DOE remedial-action plans for inactive sites; and license DOE to maintain inactive sites following remedial actions. PNL's program consists of four coordinated projects comprised of a program management task and nine research tasks that address the critical technical and safety issues for uranium recovery. Specifically, the projects endeavor to find and evaluate methods to: prevent erosion of tailings piles and prevent radon release from tailings piles; evaluate the effectiveness of interim stabilization techniques to prevent wind erosion and transport of dry tailings from active piles; estimate the dewatering and consolidation behavior of slurried tailings to promote early cover placement; design a cover-protection system to prevent erosion of the cover by expected environmental stresses; reduce seepage into ground water and prevent ground-water degradation; control solution movement and reaction with ground water in in-situ extraction operations; evaluate natural and induced restoration of ground water in in-situ extraction operations; and monitor releases to the environment from uranium recovery facilities.

  4. Thermal cycling behaviour and thermal stability of uranium-molybdenum alloys of low molybdenum content; Comportement au cyclage thermique et stabilite thermique des alliaces uranium-molybdene de faibles teneurs en molybdene

    Energy Technology Data Exchange (ETDEWEB)

    Decours, J; Fabrique, B; Peault, O [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    We have studied the behaviour during thermal cycling of as-cast U-Mo alloys whose molybdenum content varies from 0.5 to 3 per cent; results are given concerning grain stability during extended heat treatments and the effect of treatments combining protracted heating with thermal cycling. The thermal cycling treatments were carried out at 550, 575, 600 and 625 deg C for 1000 cycles; the protracted heating experiments were done at 550, 575, 600 and 625 deg C for 2000 hours (4000 hrs at 625 deg C). The 0.5 per cent alloy resists much better to the thermal cycling than does the non-alloyed uranium. This resistance is, however, much lower than that of alloys containing over l per cent, even at 550 deg C it improves after a heat treatment for grain-refining. Alloys of over 1.1 per cent have a very good resistance to a cycling treatment even at 625 deg C, and this behaviour improves with increasing concentrations up to 3 per cent. An increase in the temperature up to the {gamma}-phase has few disadvantages provided that it is followed by rapid cooling (50 to 100 deg C/min). The {alpha} grain is fine, the {gamma}-phase is of the modular form, and the behaviour during a thermal cycling treatment is satisfactory. If this cooling is slow (15 deg /hr) the {alpha}-grain is coarse and cycling treatment behaviour is identical to that of the 0.5 per cent alloy. The protracted heat treatments showed that the {alpha}-grain exhibits satisfactory stability after 2000 hours at 575, 600 and 625 deg C, and after 4000 hours at 625 deg C. A heat cycling treatment carried out after these tests affects only very little the behaviour of these alloys during cycling. (authors) [French] Nous avons etudie le comportement au cyclage thermique des alliages U-Mo, brut de coulee, dont la teneur varie de 0,5 a 3 pour cent de molybdene, les resultats de stabilite du grain au cours de traitements thermiques de longue duree, ainsi que ceux des traitements combines de longue duree et de cyclage. Les

  5. Uranium chemistry: significant advances

    International Nuclear Information System (INIS)

    Mazzanti, M.

    2011-01-01

    The author reviews recent progress in uranium chemistry achieved in CEA laboratories. Like its neighbors in the Mendeleev chart uranium undergoes hydrolysis, oxidation and disproportionation reactions which make the chemistry of these species in water highly complex. The study of the chemistry of uranium in an anhydrous medium has led to correlate the structural and electronic differences observed in the interaction of uranium(III) and the lanthanides(III) with nitrogen or sulfur molecules and the effectiveness of these molecules in An(III)/Ln(III) separation via liquid-liquid extraction. Recent work on the redox reactivity of trivalent uranium U(III) in an organic medium with molecules such as water or an azide ion (N 3 - ) in stoichiometric quantities, led to extremely interesting uranium aggregates particular those involved in actinide migration in the environment or in aggregation problems in the fuel processing cycle. Another significant advance was the discovery of a compound containing the uranyl ion with a degree of oxidation (V) UO 2 + , obtained by oxidation of uranium(III). Recently chemists have succeeded in blocking the disproportionation reaction of uranyl(V) and in stabilizing polymetallic complexes of uranyl(V), opening the way to to a systematic study of the reactivity and the electronic and magnetic properties of uranyl(V) compounds. (A.C.)

  6. Combining in situ chemical oxidation, stabilization, and anaerobic bioremediation in a single application to reduce contaminant mass and leachability in soil

    Energy Technology Data Exchange (ETDEWEB)

    Cassidy, Daniel P., E-mail: daniel.cassidy@wmich.edu [Department of Geosciences, Western Michigan University, Kalamazoo, MI 49008 (United States); Srivastava, Vipul J., E-mail: vipul.srivastava@ch2m.com [CH2M HILL, 125S Wacker, Ste 3000, Chicago, IL 60606 (United States); Dombrowski, Frank J., E-mail: frank.dombrowski@we-energies.com [We Energies, 333W Everett St., A231, Milwaukee, WI 53203 (United States); Lingle, James W., E-mail: jlingle@epri.com [Electric Power Research Institute (EPRI), 4927W Willow Road, Brown Deer, WI 53223 (United States)

    2015-10-30

    Highlights: • Portland cement and lime activated persulfate by increasing pH and temperature. • Chemical oxidation achieved BTEX and PAH removal ranging from 55% to 75%. • Activating persulfate with ISS amendments reduced leachability more than NaOH. • Native sulfate-reducing bacteria degraded PAHs within weeks after ISCO finished. • ISCO, ISS, and anaerobic bioremediation were combined in a single application. - Abstract: Laboratory batch reactors were maintained for 32 weeks to test the potential for an in situ remedy that combines chemical oxidation, stabilization, and anaerobic bioremediation in a single application to treat soil from a manufactured gas plant, contaminated with polycyclic aromatic hydrocarbons (PAH) and benzene, toluene, ethylbenzene, and xylenes (BTEX). Portland cement and slaked lime were used to activate the persulfate and to stabilize/encapsulate the contaminants that were not chemically oxidized. Native sulfate-reducing bacteria degraded residual contaminants using the sulfate left after persulfate activation. The ability of the combined remedy to reduce contaminant mass and leachability was compared with NaOH-activated persulfate, stabilization, and sulfate-reducing bioremediation as stand-alone technologies. The stabilization amendments increased pH and temperature sufficiently to activate the persulfate within 1 week. Activation with both stabilization amendments and NaOH removed between 55% and 70% of PAH and BTEX. However, combined persulfate and stabilization significantly reduced the leachability of residual BTEX and PAH compared with NaOH activation. Sulfide, 2-naphthoic acid, and the abundance of subunit A of the dissimilatory sulfite reductase gene (dsrA) were used to monitor native sulfate-reducing bacteria, which were negatively impacted by activated persulfate, but recovered completely within weeks.

  7. Combining in situ chemical oxidation, stabilization, and anaerobic bioremediation in a single application to reduce contaminant mass and leachability in soil

    International Nuclear Information System (INIS)

    Cassidy, Daniel P.; Srivastava, Vipul J.; Dombrowski, Frank J.; Lingle, James W.

    2015-01-01

    Highlights: • Portland cement and lime activated persulfate by increasing pH and temperature. • Chemical oxidation achieved BTEX and PAH removal ranging from 55% to 75%. • Activating persulfate with ISS amendments reduced leachability more than NaOH. • Native sulfate-reducing bacteria degraded PAHs within weeks after ISCO finished. • ISCO, ISS, and anaerobic bioremediation were combined in a single application. - Abstract: Laboratory batch reactors were maintained for 32 weeks to test the potential for an in situ remedy that combines chemical oxidation, stabilization, and anaerobic bioremediation in a single application to treat soil from a manufactured gas plant, contaminated with polycyclic aromatic hydrocarbons (PAH) and benzene, toluene, ethylbenzene, and xylenes (BTEX). Portland cement and slaked lime were used to activate the persulfate and to stabilize/encapsulate the contaminants that were not chemically oxidized. Native sulfate-reducing bacteria degraded residual contaminants using the sulfate left after persulfate activation. The ability of the combined remedy to reduce contaminant mass and leachability was compared with NaOH-activated persulfate, stabilization, and sulfate-reducing bioremediation as stand-alone technologies. The stabilization amendments increased pH and temperature sufficiently to activate the persulfate within 1 week. Activation with both stabilization amendments and NaOH removed between 55% and 70% of PAH and BTEX. However, combined persulfate and stabilization significantly reduced the leachability of residual BTEX and PAH compared with NaOH activation. Sulfide, 2-naphthoic acid, and the abundance of subunit A of the dissimilatory sulfite reductase gene (dsrA) were used to monitor native sulfate-reducing bacteria, which were negatively impacted by activated persulfate, but recovered completely within weeks

  8. Boiling water reactors with uranium-plutonium mixed oxide fuel. Report 5: Analysis of the reactivity coefficients and the stability of a BWR loaded with MOx fuel

    Energy Technology Data Exchange (ETDEWEB)

    Demaziere, C. [CEA Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Direction des Reacteurs Nucleaires

    2000-01-01

    This report is a part of the project titled 'Boiling Water Reactors With Uranium-Plutonium Mixed Oxide (MOx) Fuel'. The aim of this study is to model the impact of a core loading pattern containing MOx bundles upon the main characteristics of a BWR (reactivity coefficients, stability, etc.). For this purpose, the Core Management System (CMS) codes of Studsvik Scandpower are used. This package is constituted by CASMO-4/TABLES-3/SIMULATE-3. It has been shown in previous reports that these codes are able to accurately represent and model MOx bundles. This report is thus devoted to the study of BWR cores loaded (partially or totally) with MOx bundles. The plutonium quality used is the Pu type 2016 (mostly Pu-239, 56 %, and Pu-240, 26 %), but a variation of the plutonium isotopic vector was also investigated, in case of a partial MOx loading. One notices that the reactivity coefficients do not present significant changes in comparison with a full UOx loading. Nevertheless, two main problems arise: the shutdown margin at BOC is lower than 1 % and the stability to in-phase oscillations is slightly decreased. (The SIMULATE-3 version used for this study does not contain the latest MOx enhancements described in literature, since these code developments have not been provided to the department. Nevertheless, as the nominal average enrichment of the MOx bundles is 5.41 % (total amount of plutonium), which can still be considered as a relatively low enrichment, the accuracy of the CMS codes is acceptable without the use of the MOx improvements for this level of Pu enrichment.

  9. Uranium mining in North Bohemia (Straz), Czech Republic and geological evaluation prior to remediation (two abstracts together)

    International Nuclear Information System (INIS)

    Kopecky, P.; Slezak, J.

    2000-01-01

    This document presents a brief history of uranium mining in North Bohemia, Czech Republic; provides some data on the amount of uranium produced; and describes the impact of these mining activities on environment. It also outlines the results of geological surveys carried out in the area to evaluate the scope of needed restoration works. The results show the necessity of stabilization of contaminated ground water in the in-situ leaching area and give a forecast of ground water contamination distribution in thousand year future

  10. Growth of block copolymer stabilized metal nanoparticles probed simultaneously by in situ XAS and UV-Vis spectroscopy.

    Science.gov (United States)

    Nayak, C; Bhattacharyya, D; Jha, S N; Sahoo, N K

    2016-01-01

    The growth of Au and Pt nanoparticles from their respective chloride precursors using block copolymer-based reducers has been studied by simultaneous in situ measurement of XAS and UV-Vis spectroscopy at the energy-dispersive EXAFS beamline (BL-08) at INDUS-2 SRS at RRCAT, Indore, India. While the XANES spectra of the precursor give real-time information on the reduction process, the EXAFS spectra reveal the structure of the clusters formed at the intermediate stages of growth. The growth kinetics of both types of nanoparticles are found to be almost similar and are found to follow three stages, though the first stage of nucleation takes place earlier in the case of Au than in the case of Pt nanoparticles due to the difference in the reduction potential of the respective precursors. The first two stages of the growth of Au and Pt nanoparticles as obtained by in situ XAS measurements could be corroborated by simultaneous in situ measurement of UV-Vis spectroscopy also.

  11. Stabilization of mixed carbides of uranium-plutonium by zirconium. Part 1.: uranium carbide with small additions of zirconium; Etude de la stabilisation des carbures mixtes d'uranium et de plutonium par addition de zirconium. 1. partie: etude des carbures d'uranium avec de faibles additions de zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Bocker, S [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-07-01

    Cast carbide samples, being of a high density and purity, are preferable for research purposes, to samples produced by powder metallurgy methods. Samples of uranium carbide with small additions of zirconium (1 to 5 per cent) were cast, as rods, in an arc furnace. A single phase carbide with interesting qualities was produced. As cast, a dendrite structure is observed, which does not disappear, after a treatment at 1900 deg. C during 110 hours. In comparison with uranium monocarbide the compatibility with stainless steel is much improved. The specific heat (between room temperature and 2500 deg. C) is similar to the specific heat of uranium monocarbide. A study of these mixed carbides, but having a part of the uranium replaced by plutonium is under way. (author) [French] Les echantillons de monocarbures obtenus par coulee sont tres interessants pour les recherches experimentales a cause de leur grande purete, de leur densite tres elevee et de la facilite d'obtention des lingots de forme et dimensions variees. On a prepare et coule dans un four a arc des echantillons de carbures d'uranium avec de faibles additions de zirconium (1 a 5 at. pour cent). On obtient ainsi des carbures monophases presentant de meilleures proprietes que le monocarbure d'uranium. A l'etat brut de coulee on observe une structure dendritique qui n'est pas detruite par un traitement thermique de 110 heures a 1900 deg. C. La compatibilite avec l'acier inoxydable 316 (a 925 deg. C pendant 500 heures) est nettement amelioree par rapport a UC. La chaleur specifique (entre la temperature ordinaire et 2500 deg. C) et la densite sont tres peu differentes de celles du monocarbure d'uranium. Une etude concernant les composes U-Pu-Zr-C est actuellement en cours. (auteur)

  12. A systematic review of biochar research, with a focus on its stability in situ and its promise as a climate mitigation strategy.

    Directory of Open Access Journals (Sweden)

    Noel P Gurwick

    Full Text Available BACKGROUND: Claims about the environmental benefits of charring biomass and applying the resulting "biochar" to soil are impressive. If true, they could influence land management worldwide. Alleged benefits include increased crop yields, soil fertility, and water-holding capacity; the most widely discussed idea is that applying biochar to soil will mitigate climate change. This claim rests on the assumption that biochar persists for hundreds or thousands of years, thus storing carbon that would otherwise decompose. We conducted a systematic review to quantify research effort directed toward ten aspects of biochar and closely evaluated the literature concerning biochar's stability. FINDINGS: We identified 311 peer-reviewed research articles published through 2011. We found very few field studies that addressed biochar's influence on several ecosystem processes: one on soil nutrient loss, one on soil contaminants, six concerning non-CO2 greenhouse gas (GHG fluxes (some of which fail to support claims that biochar decreases non-CO2 GHG fluxes, and 16-19 on plants and soil properties. Of 74 studies related to biochar stability, transport or fate in soil, only seven estimated biochar decomposition rates in situ, with mean residence times ranging from 8 to almost 4,000 years. CONCLUSIONS: Our review shows there are not enough data to draw conclusions about how biochar production and application affect whole-system GHG budgets. Wide-ranging estimates of a key variable, biochar stability in situ, likely result from diverse environmental conditions, feedstocks, and study designs. There are even fewer data about the extent to which biochar stimulates decomposition of soil organic matter or affects non-CO2 GHG emissions. Identifying conditions where biochar amendments yield favorable GHG budgets requires a systematic field research program. Finally, evaluating biochar's suitability as a climate mitigation strategy requires comparing its effects with

  13. Stabilization

    Directory of Open Access Journals (Sweden)

    Muhammad H. Al-Malack

    2016-07-01

    Full Text Available Fuel oil flyash (FFA produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR, unconfined compressive strength (USC and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP, which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization.

  14. Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Rifle, Colorado

    International Nuclear Information System (INIS)

    1990-02-01

    This document has been structured to provide a comprehensive understanding of the remedial action proposed for the Rifle sites. That remedial action consists of removing approximately 4,185,000 cubic yards (cy) of tailings and contaminated materials from their current locations, transporting, and stabilizing the tailings material at the Estes Gulch disposal site, approximately six miles north of Rifle. The tailings and contaminated materials are comprised of approximately 597,000 cy from Old Rifle, 3,232,000 cy from New Rifle, and 322,000 cy from vicinity properties and about 34,000 cy from demolition. The remedial action plan includes specific design requirements for the detailed design and construction of the remedial action. An extensive amount of data and supporting information have been generated for this remedial action and cannot all be incorporated into this document. Pertinent information and data are included with reference given to the supporting documents

  15. Physicochemical aspects of extraction of uranium concentrate from the wastes and thermodynamic characteristics of thorium-uranium compounds

    International Nuclear Information System (INIS)

    Khamidov, F.A.

    2017-01-01

    The purpose of present work is elaboration of physicochemical aspects of extraction of uranium concentrate from the wastes and study of thermodynamic characteristics of thorium-uranium compounds. Therefore, the radiological monitoring of tailing dumps of Tajikistan has been conducted; the obtaining of uranium concentrate from the tailing dumps of uranium production has been studied; the obtaining of uranium concentrate from the tailing dumps of uranium production with application of local sorbents has been studied as well; thermal stability and thermodynamic characteristics of uranium-thorium compounds has been investigated; the flowsheets of extraction of uranium concentrate from the wastes have been elaborated.

  16. Depositional system of the Bayangobi formation, lower cretaceous and its control over in-situ leachable sandstone-type uranium deposits in Chagandelesu area, Inner Mongolia

    International Nuclear Information System (INIS)

    Zhang Wanliang

    2002-01-01

    Chagandelesu area is situated in the eastern part of Bayangobi basin, Inner Mongolia. In the Early Cretaceous, a detrital rock series (Bayangobi Formation) with a thickness of about 1000 m was formed within a down-faulted basin under the extensional tectonic regime. The Bayangobi Formation is the prospecting target for interlayer oxidation zone sandstone-type uranium deposits, and is divided into three lithologic members: the lower member-- proluvial (alluvial), subaqueous fan or fan-delta facies sediments; the middle member-shallow lacustrine-semi-deep lacustrine-deep lacustrine facies sediments; the upper member-littoral shallow lacustrine or delta facies sediments. The facies order of Bayangobi Formation represents the evolution process of basin water from the shallow (early period) to the deep (middle period) then again to the shallow (late period) level. The Bayangobi Formation composed of a third sequence order reflects respectively a lowstand system tract (LST), a transgressive system tract (TST) and a highstand system tract (HST). The author also makes an analysis on physical properties of psammites of Bayangobi Formation, and proposes that psammites of delta and littoral shallow lacustrine facies are favourable for the formation of interlayer oxidation zone sandstone-type uranium deposits

  17. Predicting the stability of horizontal wells and multi-laterals - the role of in situ stress and rock properties

    Energy Technology Data Exchange (ETDEWEB)

    Moos, A.; Peska, P. [GeoMechanics International (United States); Zoback, M. D. [Stanford Univ., CA (United States)

    1998-12-31

    A new suite of software tools, developed to study wellbore stability in a wide variety of geologic environments is introduced as means by which to accurately predict optimally-stable wellbore trajectories from knowledge of the stress tensor. In step one of the process stress, is determined from observations of failure in existing wells; in step two, this knowledge is applied to predict the stability of proposed wells while drilling, as well as later during production. Three case studies are presented to illustrate use of this approach. The examples concentrate on issues related to the stability of highly inclined wells, but the approach can be used to determine the state of stress for other purposes as well. 21 refs., 8 figs.

  18. Biodegradable surfactant stabilized nanoscale zero-valent iron for in situ treatment of vinyl chloride and 1,2-dichloroethane

    International Nuclear Information System (INIS)

    Wei, Yu-Ting; Wu, Shian-chee; Yang, Shi-Wei; Che, Choi-Hong; Lien, Hsing-Lung; Huang, De-Huang

    2012-01-01

    Highlights: ► Biodegradable surfactant stabilized nanoscale zero-valent iron (NZVI) is tested. ► Vinyl chloride and 1,2-dichloroethane are remediated by NZVI in the field. ► Multiple functions of biodegradable surfactants are confirmed. ► Biodegradable surfactants stabilize NZVI and facilitate the bioremediation. ► NZVI creates reducing conditions beneficial to an anaerobic bioremediation. - Abstract: Nanoscale zero-valent iron (NZVI) stabilized with dispersants is a promising technology for the remediation of contaminated groundwater. In this study, we demonstrated the use of biodegradable surfactant stabilized NZVI slurry for successful treatment of vinyl chloride (VC) and 1,2-dichloroethane (1,2-DCA) in a contaminated site in Taiwan. The biodegradable surfactant stabilized NZVI was coated with palladium and synthesized on-site. From monitoring the iron concentration breakthrough and distribution, it was found that the stabilized NZVI is capable of transporting in the aquifer at the test plot (200 m 2 ). VC was effectively degraded by NZVI while the 1,2-DCA degradation was relatively sluggish during the 3-month field test. Nevertheless, as 1,2-DCA is known to resist abiotic reduction by NZVI, the observation of 1,2-DCA degradation and hydrocarbon production suggested a bioremediation took place. ORP and pH results revealed that a reducing condition was achieved at the testing area facilitating the biodegradation of chlorinated organic hydrocarbons. The bioremediation may be attributed to the production of hydrogen gas as electron donor from the corrosion of NZVI in the presence of water or the added biodegradable surfactant serving as the carbon source as well as electron donor to stimulate microbial growth.

  19. Remedial action plan and site design for stabilization of the inactive uranium mill tailings site at Lowman, Idaho: Remedial action selection report for the Lowman UMTRA project site, Idaho

    International Nuclear Information System (INIS)

    Matthews, M.L.; Nagel, J.

    1991-09-01

    The inactive uranium mill tailings site near Lowman, Idaho, was designated as one of 24 abandoned uranium tailings sites to be remediated by the US Department of Energy (DOE) under the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). The UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE's remedial action plan and certify that the remedial action complies with the standards promulgated by the US Environmental Protection Agency (EPA). The remedial action plan (RAP), which includes this remedial action selection report (RAS), has been developed to serve a two-fold purpose. First, it describes the activities that are proposed by the DOE to accomplish long-term stabilization and control of residual radioactive materials at the inactive uranium processing site near Lowman, Idaho. Second, this document and the remainder of the RAP, upon concurrence and execution by the DOE, the State of Idaho, and the NRC, becomes Appendix B of the Cooperative Agreement (No. DE-FC04-85AL20535) between the DOE and the State of Idaho

  20. Uranium in Soils Integrated Demonstration: Technology summary, March 1994

    International Nuclear Information System (INIS)

    1994-03-01

    A recent Pacific Northwest Laboratory (PNL) study identified 59 waste sites at 14 DOE facilities across the nation that exhibit radionuclide contamination in excess of established limits. The rapid and efficient characterization of these sites, and the potentially contaminated regions that surround them represents a technological challenge with no existing solution. In particular, the past operations of uranium production and support facilities at several DOE sites have occasionally resulted in the local contamination of surface and subsurface soils. Such contamination commonly occurs within waste burial sites, cribs, pond bottom sediments and soils surrounding waste tanks or uranium scrap, ore, tailings, and slag heaps. The objective of the Uranium In Soils Integrated Demonstration is to develop optimal remediation methods for soils contaminated with radionuclides, principally uranium (U), at DOE sites. It is examining all phases involved in an actual cleanup, including all regulatory and permitting requirements, to expedite selection and implementation of the best technologies that show immediate and long-term effectiveness specific to the Fernald Environmental Management Project (FEMP) and applicable to other radionuclide contaminated DOE sites. The demonstration provides for technical performance evaluations and comparisons of different developmental technologies at FEMP sites, based on cost-effectiveness, risk-reduction effectiveness, technology effectiveness, and regulatory and public acceptability. Technology groups being evaluated include physical and chemical contaminant separations, in situ remediation, real-time characterization and monitoring, precise excavation, site restoration, secondary waste treatment, and soil waste stabilization

  1. Microstructure evolution, thermal stability and fractal behavior of water vapor flow assisted in situ growth poly(vinylcarbazole)-titania quantum dots nanocomposites

    Science.gov (United States)

    Mombrú, Dominique; Romero, Mariano; Faccio, Ricardo; Mombrú, Alvaro W.

    2017-12-01

    Here, we report a novel strategy for the preparation of TiO2 quantum dots fillers prepared from alkoxide precursor via in situ water vapor flow diffusion into poly(N-vinylcarbazole) host. A detailed characterization by means of infrared and Raman spectroscopy, X-ray powder diffraction, small angle X-ray scattering and differential scanning calorimetry is reported. The growth mechanism of both crystallites and particles was mostly governed by the classical coarsening reaction limited growth and the polymer host showed no detectable chemical modifications at the interface or active participation in the growing process. The main relevance of our strategy respect to the typical sol-gel growth in solution is the possibility of the interruption of the reaction by simple stopping the water vapor flow diffusion into the polymer host thus achieving good control in the nanoparticles size. The thermal stability and fractal behavior of our nanocomposites were also studied by differential scanning calorimetry and in situ small angle X-ray scattering versus temperature. Strong correlations between modifications in the fractal behavior and glass transition or fusion processes were observed for these nanocomposites.

  2. In Situ Studies of Fe4+ Stability in β-Li3Fe2(PO4)3 Cathodes for Li Ion Batteries

    DEFF Research Database (Denmark)

    Christiansen, Ane Sælland; Johnsen, Rune E.; Norby, Poul

    2015-01-01

    In commercial Fe-based batteries the Fe2+/Fe3+ oxidation states are used, however by also utilizing the Fe4+ oxidation state, intercalation of up to two Li ions per Fe ion could be possible. In this study, we investigate whether Fe4+ can be formed and stabilized in β-Li3Fe2(PO4)3. The work includes...... of Fe4+ formation. Oxidation of the organic electrolyte is inevitable at 4.5 V but this alone cannot explain the volume change. Instead, a reversible oxygen redox process (O2− → O−) could possibly explain and charge compensate for the reversible extraction of lithium ions from β-Li3Fe2(PO4)3....... in situ synchrotron X-ray powder diffraction studies (XRPD) during charging of β-Li3Fe2(PO4)3 up to 5.0 V vs. Li/Li+. A novel capillary-based micro battery cell for in situ XRPD has been designed for this. During charge, a plateau at 4.5 V was found and a small contraction in volume was observed...

  3. Development of an In-Situ Microsensor for the Measurements of Chromium and Uranium in Groundwater at DOE Sites - Final Report

    CERN Document Server

    Wang, J

    2000-01-01

    The goal of this program is to develop, optimize and deploy a silicon-based micromachined stripping analyzer for field monitoring trace levels of chromium and uranium. Such system will integrate the sample-handling steps and necessary chemical reactions (using a flow-injection operation) with the actual adsorptive stripping measurement on a small planar chip. Besides the drastic reduction in the size of the analytical system, such miniaturization should lead to increased speed, minimal reagent consumption and disposal, higher sensitivity and improved precision, and would thus revolutionize the way by which toxic metals are being monitored. The new electrochemical devices should have an enormous impact upon pollution control and prevention, as they should lead to a substantially more effective and economic monitoring of priority metal pollutants. The project combined fundamental and practical aspects of electroanalysis and microsystems to meet the monitoring and sensing needs of DOE sites.

  4. Understanding the Thermal Stability of Palladium-Platinum Core-Shell Nanocrystals by In Situ Transmission Electron Microscopy and Density Functional Theory.

    Science.gov (United States)

    Vara, Madeline; Roling, Luke T; Wang, Xue; Elnabawy, Ahmed O; Hood, Zachary D; Chi, Miaofang; Mavrikakis, Manos; Xia, Younan

    2017-05-23

    Core-shell nanocrystals offer many advantages for heterogeneous catalysis, including precise control over both the surface structure and composition, as well as reduction in loading for rare and costly metals. Although many catalytic processes are operated at elevated temperatures, the adverse impacts of heating on the shape and structure of core-shell nanocrystals are yet to be understood. In this work, we used ex situ heating experiments to demonstrate that Pd@Pt 4L core-shell nanoscale cubes and octahedra are promising for catalytic applications at temperatures up to 400 °C. We also used in situ transmission electron microscopy to monitor the thermal stability of the core-shell nanocrystals in real time. Our results demonstrate a facet dependence for the thermal stability in terms of shape and composition. Specifically, the cubes enclosed by {100} facets readily deform shape at a temperature 300 °C lower than that of the octahedral counterparts enclosed by {111} facets. A reversed trend is observed for composition, as alloying between the Pd core and the Pt shell of an octahedron occurs at a temperature 200 °C lower than that for the cubic counterpart. Density functional theory calculations provide atomic-level explanations for the experimentally observed behaviors, demonstrating that the barriers for edge reconstruction determine the relative ease of shape deformation for cubes compared to octahedra. The opposite trend for alloying of the core-shell structure can be attributed to a higher propensity for subsurface Pt vacancy formation in octahedra than in cubes.

  5. Worldwide developments in uranium

    International Nuclear Information System (INIS)

    Hoellen, E.E.

    1987-01-01

    World uranium production will continue to change in most major producing nations. Canadian production will increase and will be increasingly dominated by western producers as eastern Canadian high-cost production declines. Australian production will increase as major projects come into operation before 2000. US production will stabilize through the end of the century. South African production will be dependent upon the worldwide support for economic sanctions. China's entry into the world market injects yet another variable into the already cloudy supply picture. Many risks and uncertainties will face uranium producers through the 1980s. Recognizing that the uranium industry is not a fast-growing market, many existing and potential producers are seeking alternate investment courses, causing a restructuring of the world uranium production industry in ways not anticipated even a few years ago. During the restructuring process, world uranium production will most likely continue to exceed uranium consumption, resulting in a further buildup of world uranium inventories. Inventory sales will continue to redistribute this material. As inventory selling runs its course, users will turn to normal sources of supply, stimulating additional production to meet needs. Stimulation in the form of higher prices will be determined by how fast producers are willing and able to return to the market. Production costs are expected to have an increasing impact as it has become apparent that uranium resources are large in comparison to projected consumption. Conversely, security-of-supply issues have seemed to be of decreasing magnitude as Canada, Australia, and other non-US producers continue to meet delivery commitments

  6. Uranium mill tailings management

    International Nuclear Information System (INIS)

    1982-01-01

    Facilities for the disposal of uranium mill tailings will invariably be subjected to geomorphological and climatological influences in the long-term. Proceedings of a workshop discuss how the principles of geomorphology can be applied to the siting, design, construction, decommissioning and rehabilitation of disposal facilities in order to provide for long-term containment and stability of tailings. The characteristics of tailings and their behaviour after disposal influence the potential impacts which might occur in the long-term. Proceedings of another workshop examine the technologies for uranium ore processing and tailings conditioning with a view to identifying improvements that could be made in such characteristics

  7. In situ immobilization of uranium in structured porous media via biomineralization at the fracture/matrix interface (FRC Area 2 field project)

    International Nuclear Information System (INIS)

    Timothy D. Scheibe; Eric E. Roden; Scott C. Brooks; John M. Zachara

    2004-01-01

    The original hypothesis: 'Radionuclides in low-permeability porous matrix regions of fractured saprolite can be effectively isolated and immobilized by stimulating localized in-situ biological activity in highly-permeable fractured and microfractured zones within the saprolite'. The revised hypothesis: 'In heterogeneous porous media, microbial activity can be stimulated at interfaces between zones of high and low groundwater flow rates in such a manner as to create a local, distributed redox barrier. Such a barrier will inhibit the transfer of contaminants from the low-flow zones that serve as long-term contaminant sources into the high-flow zones that transport contaminants to receptors'.

  8. Remedial action plan and site design for stabilization of the inactive uranium mill tailings sites at Slick Rock, Colorado: Appendix B to Attachment 3, lithologic logs

    International Nuclear Information System (INIS)

    1994-03-01

    This appendix contains the lithologic logs and monitor well construction information for the remedial action plan for uranium mill tailings sites at Slick Rock, CO. Data from each borehole is presented graphically and a stratigraphic description is given

  9. Study on the preparation and stability of uranium carbide samples for the determination of oxygen, hydrogen and nitrogen by fusion under high vacuum

    International Nuclear Information System (INIS)

    Perez Garcia, M.

    1966-01-01

    In view of the high reactivity of uranium carbide, the method employed for the preparation of the sample for the analysis of its gas content: oxygen, hydrogen and nitrogen, has a decisive influence on the analytical results. The variation in the O 2 , H 2 and N 2 content of the uranium carbide has been studied in this paper with the methods utilized for the sample preparation (grinding and cutting). (Author) 9 refs

  10. Use of a Ca-Citrate-Phosphate Solution to Form Hydroxyapatite for Uranium Stabilization of Old Rifle Sediments: Laboratory Proof of Principle Studies

    Energy Technology Data Exchange (ETDEWEB)

    Szescody, James E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Moore, Robert C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rigali, Mark J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Vermeul, Vincent R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Luellen, Jon [AECOM, Denver, CO (United States)

    2016-03-01

    The Old Rifle Site is a former vanadium and uranium ore-processing facility located adjacent to the Colorado River and approximately 0.3 miles east of the city of Rifle, CO. The former processing facilities have been removed and the site uranium mill tailings are interned at a disposal cell north of the city of Rifle. However, some low level remnant uranium contamination still exists at the Old Rifle site. In 2002, the United States Nuclear Regulatory Commission (US NRC) concurred with United States Department of Energy (US DOE) on a groundwater compliance strategy of natural flushing with institutional controls to decrease contaminant concentrations in the aquifer. In addition to active monitoring of contaminant concentrations, the site is also used for DOE Legacy Management (LM) and other DOE-funded small-scale field tests of remediation technologies. The purpose of this laboratory scale study was to evaluate the effectiveness of a hydroxyapatite (Ca10(PO4)6(OH)2) permeable reactive barrier and source area treatment in Old Rifle sediments. Phosphate treatment impact was evaluated by comparing uranium leaching and surface phase changes in untreated to PO4-treated sediments. The impact of the amount of phosphate precipitation in the sediment on uranium mobility was evaluated with three different phosphate loadings. A range of flow velocity and uranium concentration conditions (i.e., uranium flux through the phosphate-treated sediment) was also evaluated to quantify the uranium uptake mass and rate by the phosphate precipitate.

  11. Czechoslovak uranium

    International Nuclear Information System (INIS)

    Pluskal, O.

    1992-01-01

    Data and knowledge related to the prospecting, mining, processing and export of uranium ores in Czechoslovakia are presented. In the years between 1945 and January 1, 1991, 98,461.1 t of uranium were extracted. In the period 1965-1990 the uranium industry was subsidized from the state budget to a total of 38.5 billion CSK. The subsidies were put into extraction, investments and geologic prospecting; the latter was at first, ie. till 1960 financed by the former USSR, later on the two parties shared costs on a 1:1 basis. Since 1981 the prospecting has been entirely financed from the Czechoslovak state budget. On Czechoslovak territory uranium has been extracted from deposits which may be classified as vein-type deposits, deposits in uranium-bearing sandstones and deposits connected with weathering processes. The future of mining, however, is almost exclusively being connected with deposits in uranium-bearing sandstones. A brief description and characteristic is given of all uranium deposits on Czechoslovak territory, and the organization of uranium mining in Czechoslovakia is described as is the approach used in the world to evaluate uranium deposits; uranium prices and actual resources are also given. (Z.S.) 3 figs

  12. Retrieval of buried depleted uranium from the T-1 trench

    International Nuclear Information System (INIS)

    Burmeister, M.; Castaneda, N.; Hull, C.; Barbour, D.; Quapp, W.J.

    1998-01-01

    The Trench 1 remediation project will be conducted this year to retrieve depleted uranium and other associated materials from a trench at Rocky Flats Environmental Technology Site. The excavated materials will be segregated and stabilized for shipment. The depleted uranium will be treated at an offsite facility which utilizes a novel approach for waste minimization and disposal through utilization of a combination of uranium recycling and volume efficient uranium stabilization

  13. In-situ stabilization of radioactively contaminated low-level solid wastes buried in shallow trenches: an assessment

    International Nuclear Information System (INIS)

    Arora, H.S.; Tamura, T.; Boegly, W.J.

    1980-09-01

    The potential effectiveness of materials for in-situ encapsulation of low-level, radioactively contaminated solid waste buried in shallow trenches is enumerated. Cement, clay materials, and miscellaneous sorbents, aqueous and nonaqueous gelling fluids and their combinations are available to solidify contaminated free water in trenches, to fill open voids, and to minimize radionuclide mobility. The success of the grouting technique will depend on the availability of reliable geohydrologic data and laboratory development of a mix with enhanced sorption capacity for dominant radionuclides present in the trenches. A cement-bentonite-based grout mix with low consistency for pumping, several hours controlled rate of hardening, negligible bleeding, and more than 170 kPa (25 psi) compressive strength are a few of the suggested parameters in laboratory mix development. Cost estimates of a cement-bentonite-based grout mix indicate that effective and durable encapsulation can be accomplished at a reasonable cost (about $113 per cubic meter). However, extensive implementation of the method suggests the need for a field demonstration of the method. 53 references

  14. The radiation stability of glycine in solid CO2 - In situ laboratory measurements with applications to Mars

    Science.gov (United States)

    Gerakines, Perry A.; Hudson, Reggie L.

    2015-05-01

    The detection of biologically important, organic molecules on Mars is an important goal that may soon be reached. However, the current small number of organic detections at the martian surface may be due to the harsh UV and radiation conditions there. It seems likely that a successful search will require probing the subsurface of Mars, where penetrating cosmic rays and solar energetic particles dominate the radiation environment, with an influence that weakens with depth. Toward the goal of understanding the survival of organic molecules in cold radiation-rich environments on Mars, we present new kinetics data on the radiolytic destruction of glycine diluted in frozen carbon dioxide. Rate constants were measured in situ with infrared spectroscopy, without additional sample manipulation, for irradiations at 25, 50, and 75 K with 0.8-MeV protons. The resulting half-lives for glycine in CO2-ice are compared to previous results for glycine in H2O-ice and show that glycine in CO2-ice is much less stable in a radiation environment, with destruction rate constants ∼20-40 times higher than glycine in H2O-ice. Extrapolation of these results to conditions in the martian subsurface results in half-lives estimated to be less than 100-200 Myr even at depths of a few meters.

  15. In Situ Formation of AgCo Stabilized on Graphitic Carbon Nitride and Concomitant Hydrolysis of Ammonia Borane to Hydrogen.

    Science.gov (United States)

    Wang, Qi; Xu, Caili; Ming, Mei; Yang, Yingchun; Xu, Bin; Wang, Yi; Zhang, Yun; Wu, Jie; Fan, Guangyin

    2018-04-26

    The development of highly-efficient heterogeneous supported catalysts for catalytic hydrolysis of ammonia borane to yield hydrogen is of significant importance considering the versatile usages of hydrogen. Herein, we reported the in situ synthesis of AgCo bimetallic nanoparticles supported on g-C₃N₄ and concomitant hydrolysis of ammonia borane for hydrogen evolution at room temperature. The as-synthesized Ag 0.1 Co 0.9 /g-C₃N₄ catalysts displayed the highest turnover frequency (TOF) value of 249.02 mol H₂·(mol Ag ·min) −1 for hydrogen evolution from the hydrolysis of ammonia borane, which was higher than many other reported values. Furthermore, the Ag 0.1 Co 0.9 /g-C₃N₄ catalyst could be recycled during five consecutive runs. The study proves that Ag 0.1 Co 0.9 /g-C₃N₄ is a potential catalytic material toward the hydrolysis of ammonia borane for hydrogen production.

  16. In Situ Formation of AgCo Stabilized on Graphitic Carbon Nitride and Concomitant Hydrolysis of Ammonia Borane to Hydrogen

    Directory of Open Access Journals (Sweden)

    Qi Wang

    2018-04-01

    Full Text Available The development of highly-efficient heterogeneous supported catalysts for catalytic hydrolysis of ammonia borane to yield hydrogen is of significant importance considering the versatile usages of hydrogen. Herein, we reported the in situ synthesis of AgCo bimetallic nanoparticles supported on g-C3N4 and concomitant hydrolysis of ammonia borane for hydrogen evolution at room temperature. The as-synthesized Ag0.1Co0.9/g-C3N4 catalysts displayed the highest turnover frequency (TOF value of 249.02 mol H2·(molAg·min−1 for hydrogen evolution from the hydrolysis of ammonia borane, which was higher than many other reported values. Furthermore, the Ag0.1Co0.9/g-C3N4 catalyst could be recycled during five consecutive runs. The study proves that Ag0.1Co0.9/g-C3N4 is a potential catalytic material toward the hydrolysis of ammonia borane for hydrogen production.

  17. In situ growth of hollow gold-silver nanoshells within porous silica offers tunable plasmonic extinctions and enhanced colloidal stability.

    Science.gov (United States)

    Li, Chien-Hung; Jamison, Andrew C; Rittikulsittichai, Supparesk; Lee, Tai-Chou; Lee, T Randall

    2014-11-26

    Porous silica-coated hollow gold-silver nanoshells were successfully synthesized utilizing a procedure where the porous silica shell was produced prior to the transformation of the metallic core, providing enhanced control over the structure/composition of the bimetallic hollow core. By varying the reaction time and the precise amount of gold salt solution added to a porous silica-coated silver-core template solution, composite nanoparticles were tailored to reveal a readily tunable surface plasmon resonance that could be centered across the visible and near-IR spectral regions (∼445-800 nm). Characterization by X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and transmission electron microscopy revealed that the synthetic methodology afforded particles having uniform composition, size, and shape. The optical properties were evaluated by absorption/extinction spectroscopy. The stability of colloidal solutions of our composite nanoparticles as a function of pH was also investigated, revealing that the nanoshells remain intact over a wide range of conditions (i.e., pH 2-10). The facile tunability, enhanced stability, and relatively small diameter of these composite particles (∼110 nm) makes them promising candidates for use in tumor ablation or as photothermal drug-delivery agents.

  18. Final Report DE-SC0006997; PI Sharp; Coupled Biological and Micro-XAS/XRF Analysis of In Situ Uranium Biogeochemical Processes

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, Jonathan O. [Colorado School of Mines, Golden, CO (United States)

    2016-03-30

    Project Overview: The impact of the original seed award was substantially increased by leveraging a postdoctoral fellowship (Marie Curie Postdoctoral Fellowship) and parallel funds from (A) synergistic project supported by NSF and (B) with DOE collaborators (PI’s Ranville and Williams) as well as no-cost extension that greatly increased the impact and publications associated with the project. In aligning with SBR priorities, the project’s focus was extended more broadly to explore coupled biogeochemical analysis of metal (im)mobilization processes beyond uranium with a foundation in integrating microbial ecology with geochemical analyses. This included investigations of arsenic and zinc during sulfate reducing conditions in addition to direct microbial reduction of metals. Complimentary work with NSF funding and collaborative DOE interactions further increased the project scope to investigate metal (im)mobilization coupled to biogeochemical perturbations in forest ecosystems with an emphasis on coupled carbon and metal biogeochemistry. In total, the project was highly impactful and resulted in 9 publications and directly supported salary/tuition for 3 graduate students at various stages of their academic careers as well as my promotion to Associate Professor. In going forward, findings provided inspiration for a two subsequent proposals with collaborators at Lawrence Berkeley Laboratory and others that are currently in review (as of March 2016).

  19. Solubility measurement of uranium in uranium-contaminated soils

    International Nuclear Information System (INIS)

    Lee, S.Y.; Elless, M.; Hoffman, F.

    1993-08-01

    A short-term equilibration study involving two uranium-contaminated soils at the Fernald site was conducted as part of the In Situ Remediation Integrated Program. The goal of this study is to predict the behavior of uranium during on-site remediation of these soils. Geochemical modeling was performed on the aqueous species dissolved from these soils following the equilibration study to predict the on-site uranium leaching and transport processes. The soluble levels of total uranium, calcium, magnesium, and carbonate increased continually for the first four weeks. After the first four weeks, these components either reached a steady-state equilibrium or continued linearity throughout the study. Aluminum, potassium, and iron, reached a steady-state concentration within three days. Silica levels approximated the predicted solubility of quartz throughout the study. A much higher level of dissolved uranium was observed in the soil contaminated from spillage of uranium-laden solvents and process effluents than in the soil contaminated from settling of airborne uranium particles ejected from the nearby incinerator. The high levels observed for soluble calcium, magnesium, and bicarbonate are probably the result of magnesium and/or calcium carbonate minerals dissolving in these soils. Geochemical modeling confirms that the uranyl-carbonate complexes are the most stable and dominant in these solutions. The use of carbonate minerals on these soils for erosion control and road construction activities contributes to the leaching of uranium from contaminated soil particles. Dissolved carbonates promote uranium solubility, forming highly mobile anionic species. Mobile uranium species are contaminating the groundwater underlying these soils. The development of a site-specific remediation technology is urgently needed for the FEMP site

  20. Structural changes and thermal stability of charged LiNixMnyCozO₂ cathode materials studied by combined in situ time-resolved XRD and mass spectroscopy.

    Science.gov (United States)

    Bak, Seong-Min; Hu, Enyuan; Zhou, Yongning; Yu, Xiqian; Senanayake, Sanjaya D; Cho, Sung-Jin; Kim, Kwang-Bum; Chung, Kyung Yoon; Yang, Xiao-Qing; Nam, Kyung-Wan

    2014-12-24

    Thermal stability of charged LiNixMnyCozO2 (NMC, with x + y + z = 1, x:y:z = 4:3:3 (NMC433), 5:3:2 (NMC532), 6:2:2 (NMC622), and 8:1:1 (NMC811)) cathode materials is systematically studied using combined in situ time-resolved X-ray diffraction and mass spectroscopy (TR-XRD/MS) techniques upon heating up to 600 °C. The TR-XRD/MS results indicate that the content of Ni, Co, and Mn significantly affects both the structural changes and the oxygen release features during heating: the more Ni and less Co and Mn, the lower the onset temperature of the phase transition (i.e., thermal decomposition) and the larger amount of oxygen release. Interestingly, the NMC532 seems to be the optimized composition to maintain a reasonably good thermal stability, comparable to the low-nickel-content materials (e.g., NMC333 and NMC433), while having a high capacity close to the high-nickel-content materials (e.g., NMC811 and NMC622). The origin of the thermal decomposition of NMC cathode materials was elucidated by the changes in the oxidation states of each transition metal (TM) cations (i.e., Ni, Co, and Mn) and their site preferences during thermal decomposition. It is revealed that Mn ions mainly occupy the 3a octahedral sites of a layered structure (R3̅m) but Co ions prefer to migrate to the 8a tetrahedral sites of a spinel structure (Fd3̅m) during the thermal decomposition. Such element-dependent cation migration plays a very important role in the thermal stability of NMC cathode materials. The reasonably good thermal stability and high capacity characteristics of the NMC532 composition is originated from the well-balanced ratio of nickel content to manganese and cobalt contents. This systematic study provides insight into the rational design of NMC-based cathode materials with a desired balance between thermal stability and high energy density.

  1. Modelling the Small Throw Fault Effect on the Stability of a Mining Roadway and Its Verification by In Situ Investigation

    Directory of Open Access Journals (Sweden)

    Małkowski Piotr

    2017-12-01

    Full Text Available The small throw fault zones cause serious problems for mining engineers. The knowledge about the range of fractured zone around the roadway and about roadway’s contour deformations helps a lot with the right support design or its reinforcement. The paper presents the results of numerical analysis of the effect of a small throw fault zone on the convergence of the mining roadway and the extent of the fracturing induced around the roadway. The computations were performed on a dozen physical models featuring various parameters of rock mass and support for the purpose to select the settings that reflects most suitably the behavior of tectonically disturbed and undisturbed rocks around the roadway. Finally, the results of the calculations were verified by comparing them with in situ convergence measurements carried out in the maingate D-2 in the “Borynia-Zofiówka-Jastrzębie” coal mine. Based on the results of measurements it may be concluded that the rock mass displacements around a roadway section within a fault zone during a year were four times in average greater than in the section tectonically unaffected. The results of numerical calculations show that extent of the yielding zone in the roof reaches two times the throw of the fault, in the floor 3 times the throw, and horizontally approx. 1.5 to 1.8 times the width of modelled fault zone. Only a few elasto-plastic models or models with joints between the rock beds can be recommended for predicting the performance of a roadway which is within a fault zone. It is possible, using these models, to design the roadway support of sufficient load bearing capacity at the tectonically disturbed section.

  2. Final Technical Report. Factors Controlling In Situ Uranium and Technetium Bio-Reduction and Reoxidation at the NABIR Field Research Center

    International Nuclear Information System (INIS)

    Dr. Jonathan D. Istok , Oregon State University; Dr. Lee Krumholz, University of Oklahoma; Dr. James McKinley, Pacific Northwest National Laboratory; Dr. Baohua Gu, Oak Ridge National Laboratory

    2006-01-01

    The overall goal of this project was to better understand factors and processes controlling microbially-mediated reduction and reoxidation of U and Tc in the unconsolidated residuum overlying the Nolichucky shale at the Field Research Center (FRC) at Oak Ridge National Laboratory. Project activities were designed to test the following hypotheses: (1) The small rates of denitrification and U bio-reduction observed in laboratory incubations of sediments from FRC Area 1 at low pH (< 5) are due to the presence of high concentrations of toxic metals (especially Al and Ni). Rates of Tc reduction will also be small at low pH in the presence of high concentrations of toxic metals. (2) In situ rates of U and perhaps Tc bio-reduction can be increased by increasing system pH and thus precipitating toxic metals from solution. (3) In situ rates of U and Tc bio-reduction can be increased by the addition of humic substances, which complex toxic metals such as Al and Ni, buffer pH, and serve as electron shuttles to facilitate U and Tc reduction. (4) Microbially-reduced U and Tc are rapidly oxidized in the presence of high concentrations of NO3- and the denitrification intermediates NO2-, N2O, and NO. (5) An electron-donor-addition strategy (type and form of donor, with or without pH adjustment and with or without the co-addition of humic substances) can be devised to reduce U and Tc concentrations for an extended period of time in low pH groundwater in the presence of high concentrations of NO3-, Al, and Ni. This strategy operates by removing or complexing these components of FRC groundwater to allow the subsequent reduction of U(VI) and Tc(VII)

  3. Uranium ores

    International Nuclear Information System (INIS)

    Poty, B.; Roux, J.

    1998-01-01

    The processing of uranium ores for uranium extraction and concentration is not much different than the processing of other metallic ores. However, thanks to its radioactive property, the prospecting of uranium ores can be performed using geophysical methods. Surface and sub-surface detection methods are a combination of radioactive measurement methods (radium, radon etc..) and classical mining and petroleum prospecting methods. Worldwide uranium prospecting has been more or less active during the last 50 years, but the rise of raw material and energy prices between 1970 and 1980 has incited several countries to develop their nuclear industry in order to diversify their resources and improve their energy independence. The result is a considerable increase of nuclear fuels demand between 1980 and 1990. This paper describes successively: the uranium prospecting methods (direct, indirect and methodology), the uranium deposits (economical definition, uranium ores, and deposits), the exploitation of uranium ores (use of radioactivity, radioprotection, effluents), the worldwide uranium resources (definition of the different categories and present day state of worldwide resources). (J.S.)

  4. Uranium market

    International Nuclear Information System (INIS)

    Rubini, L.A.; Asem, M.A.D.

    1990-01-01

    The historical development of the uranium market is present in two periods: The initial period 1947-1970 and from 1970 onwards, with the establishment of a commercial market. The world uranium requirements are derived from the corresponding forecast of nuclear generating capacity, with, particular emphasis to the brazilian requirements. The forecast of uranium production until the year 2000 is presented considering existing inventories and the already committed demand. The balance between production and requirements is analysed. Finally the types of contracts currently being used and the development of uranium prices in the world market are considered. (author)

  5. Uranium enrichment

    International Nuclear Information System (INIS)

    1990-01-01

    This report looks at the following issues: How much Soviet uranium ore and enriched uranium are imported into the United States and what is the extent to which utilities flag swap to disguise these purchases? What are the U.S.S.R.'s enriched uranium trading practices? To what extent are utilities required to return used fuel to the Soviet Union as part of the enriched uranium sales agreement? Why have U.S. utilities ended their contracts to buy enrichment services from DOE?

  6. Anticorrosion protection of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Goncharov, Ivan D.; Kazakovskaya, Tatiana; Tukmakov, Victor; Shapovalov, Vyacheslav [Russian Federal Nuclear Center-VNIIEF, 37, Mira Ave., RU-607190 Sarov (Nizhnii Gorod), 010450 (Russian Federation)

    2004-07-01

    inter-metallides are not formed in this case (to compare: Ni inter-metallides are formed at temperature plus 300 - 350 deg C). If temperature does not exceed plus 80 deg. C thermo-vacuum annealing is acceptable at temperature plus 600 deg C. providing high stability of uranium surface to all kinds of oxidizing corrosion in air. (authors)

  7. Anticorrosion protection of uranium

    International Nuclear Information System (INIS)

    Goncharov, Ivan D.; Kazakovskaya, Tatiana; Tukmakov, Victor; Shapovalov, Vyacheslav

    2004-01-01

    inter-metallides are not formed in this case (to compare: Ni inter-metallides are formed at temperature plus 300 - 350 deg C). If temperature does not exceed plus 80 deg. C thermo-vacuum annealing is acceptable at temperature plus 600 deg C. providing high stability of uranium surface to all kinds of oxidizing corrosion in air. (authors)

  8. High impact of in situ dextran coating on biocompatibility, stability and magnetic properties of iron oxide nanoparticles.

    Science.gov (United States)

    Shaterabadi, Zhila; Nabiyouni, Gholamreza; Soleymani, Meysam

    2017-06-01

    Biocompatible ferrofluids based on dextran coated iron oxide nanoparticles were fabricated by conventional co-precipitation method. The experimental results show that the presence of dextran in reaction medium not only causes to the appearance of superparamagnetic behavior but also results in significant suppression in saturation magnetization of dextran coated samples. These results can be attributed to size reduction originated from the role of dextran as a surfactant. Moreover, weight ratio of dextran to magnetic nanoparticles has a remarkable influence on size and magnetic properties of nanoparticles, so that the sample prepared with a higher weight ratio of dextran to nanoparticles has the smaller size and saturation magnetization compare with the other samples. In addition, the ferrofluids containing such nanoparticles have an excellent stability at physiological pH for several months. Furthermore, the biocompatibility studies reveal that surface modification of nanoparticles by dextran dramatically decreases the cytotoxicity of bare nanoparticles and consequently improves their potential application for diagnostic and therapeutic purposes. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Durango, Colorado: Attachment 3, Groundwater hydrology report. Revised final report

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-01

    The US Environmental Protection Agency (EPA) has established health and environmental protection regulations to correct and prevent groundwater contamination resulting from processing activities at inactive uranium milling sites. According to the Uranium Mill Tailings Radiation Control Act of 1978, (UMTRCA) the US Department of Energy (DOE) is responsible for assessing the inactive uranium processing sites. The DOE has determined this assessment shall include information on hydrogeologic site characterization. The water resources protection strategy that describes how the proposed action will comply with the EPA groundwater protection standards is presented in Attachment 4. Site characterization activities discussed in this section include: Characterization of the hydrogeologic environment; characterization of existing groundwater quality; definition of physical and chemical characteristics of the potential contaminant source; and description of local water resources.

  10. Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Durango, Colorado: Attachment 3, Groundwater hydrology report

    International Nuclear Information System (INIS)

    1991-12-01

    The US Environmental Protection Agency (EPA) has established health and environmental protection regulations to correct and prevent groundwater contamination resulting from processing activities at inactive uranium milling sites. According to the Uranium Mill Tailings Radiation Control Act of 1978, (UMTRCA) the US Department of Energy (DOE) is responsible for assessing the inactive uranium processing sites. The DOE has determined this assessment shall include information on hydrogeologic site characterization. The water resources protection strategy that describes how the proposed action will comply with the EPA groundwater protection standards is presented in Attachment 4. Site characterization activities discussed in this section include: Characterization of the hydrogeologic environment; characterization of existing groundwater quality; definition of physical and chemical characteristics of the potential contaminant source; and description of local water resources

  11. Uranium production and the environment in Kazakhstan

    International Nuclear Information System (INIS)

    Fyodorov, G.V.

    2002-01-01

    The production of uranium from open-pit and underground mines in Kazakhstan has terminated. Currently, uranium is extracted in Kazakhstan only by the In Situ Leaching (ISL) method. This method has a number of economical and ecological advantages. During a short period in the 70s-80s, Kazakhstan created a firm basis for developing uranium extraction by the ISL method. Now more than half of the world's uranium reserves amenable to the ISL method are located in Kazakhstan. By 2005, a significant increase in uranium production is planned. Thereby, Kazakhstan has the ability to grow into a world leader in uranium extraction through a lower cost and low environmental impact operations using the ISL method. (author)

  12. Uranium mining

    International Nuclear Information System (INIS)

    Lange, G.

    1975-01-01

    The winning of uranium ore is the first stage of the fuel cycle. The whole complex of questions to be considered when evaluating the profitability of an ore mine is shortly outlined, and the possible mining techniques are described. Some data on uranium mining in the western world are also given. (RB) [de

  13. Uranium enrichment

    International Nuclear Information System (INIS)

    1989-01-01

    GAO was asked to address several questions concerning a number of proposed uranium enrichment bills introduced during the 100th Congress. The bill would have restructured the Department of Energy's uranium enrichment program as a government corporation to allow it to compete more effectively in the domestic and international markets. Some of GAO's findings discussed are: uranium market experts believe and existing market models show that the proposed DOE purchase of a $750 million of uranium from domestic producers may not significantly increase production because of large producer-held inventories; excess uranium enrichment production capacity exists throughout the world; therefore, foreign producers are expected to compete heavily in the United States throughout the 1990s as utilities' contracts with DOE expire; and according to a 1988 agreement between DOE's Offices of Nuclear Energy and Defense Programs, enrichment decommissioning costs, estimated to total $3.6 billion for planning purposes, will be shared by the commercial enrichment program and the government

  14. Uranium resources

    International Nuclear Information System (INIS)

    1976-01-01

    This is a press release issued by the OECD on 9th March 1976. It is stated that the steep increases in demand for uranium foreseen in and beyond the 1980's, with doubling times of the order of six to seven years, will inevitably create formidable problems for the industry. Further substantial efforts will be needed in prospecting for new uranium reserves. Information is given in tabular or graphical form on the following: reasonably assured resources, country by country; uranium production capacities, country by country; world nuclear power growth; world annual uranium requirements; world annual separative requirements; world annual light water reactor fuel reprocessing requirements; distribution of reactor types (LWR, SGHWR, AGR, HWR, HJR, GG, FBR); and world fuel cycle capital requirements. The information is based on the latest report on Uranium Resources Production and Demand, jointly issued by the OECD's Nuclear Energy Agency (NEA) and the International Atomic Energy Agency. (U.K.)

  15. Preparation of electrodeless discharge lamps for emission studies of uranium isotopes at trace level

    International Nuclear Information System (INIS)

    Bhowmick, G.K.; Verma, R.; Verma, M.K.; Raman, V.A.; Joshi, A.R.; Deo, M.N.; Gantayet, L.M.; Tiwari, A.K.; Ramakumar, K.L.; Kumar, Navin

    2010-01-01

    A simplified method for preparation of electrodeless discharge lamp for uranium isotopes with specific concerns for 232 U is described. Micro-gram quantities of solid uranium oxides and aqueous solution of uranium nitrate have been used as a starting material for in situ synthesis of uranium tetraiodide. High temperature iodination reaction is carried out in the presence of inert gas neon. By careful design, the preparation time and surface area of quartz reaction tubes have been reduced considerably. The latter decreases the level of contamination which has a direct bearing on the operational lifetime of the lamps. Incorporation of steps to purify the product from an unwanted material improved the stability of the lamps. The procedure provides a safe and convenient way of handling 232 U in particular but can be extended in general to any actinides having radioactivity similar to that of freshly separated 232 U. Characteristic emission of uranium isotopes have been recorded by Fourier Transform Spectrometer to show the satisfactory operation of the lamps as well as their usage for studying emission spectra of the specific isotope.

  16. Validation of an in situ solidification/stabilization technique for hazardous barium and cyanide waste for safe disposal into a secured landfill.

    Science.gov (United States)

    Vaidya, Rucha; Kodam, Kisan; Ghole, Vikram; Surya Mohan Rao, K

    2010-09-01

    The aim of the present study was to devise and validate an appropriate treatment process for disposal of hazardous barium and cyanide waste into a landfill at a Common Hazardous Waste Treatment Storage Disposal Facility (CHWTSDF). The waste was generated during the process of hardening of steel components and contains cyanide (reactive) and barium (toxic) as major contaminants. In the present study chemical fixation of the contaminants was carried out. The cyanide was treated by alkali chlorination with calcium hypochlorite and barium by precipitation with sodium sulfate as barium sulfate. The pretreated mixture was then solidified and stabilized by binding with a combination of slag cement, ordinary Portland cement and fly ash, molded into blocks (5 x 5 x 5 cm) and cured for a period of 3, 7 and 28 days. The final experiments were conducted with 18 recipe mixtures of waste + additive:binder (W:B) ratios. The W:B ratios were taken as 80:20, 70:30 and 50:50. The optimum proportions of additives and binders were finalized on the basis of the criteria of unconfined compressive strength and leachability. The leachability studies were conducted using the Toxicity Characteristic Leaching Procedure. The blocks were analyzed for various physical and leachable chemical parameters at the end of each curing period. Based on the results of the analysis, two recipe mixtures, with compositions - 50% of [waste + (120 g Ca(OCl)(2) + 290 g Na(2)SO(4)) kg(-1) of waste] + 50% of binders, were validated for in situ stabilization into a secured landfill of CHWTSDF. 2010 Elsevier Ltd. All rights reserved.