WorldWideScience

Sample records for natural uranium processing

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

    Energy Technology Data Exchange (ETDEWEB)

    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/sub 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.

  2. Uranium processing and properties

    CERN Document Server

    2013-01-01

    Covers a broad spectrum of topics and applications that deal with uranium processing and the properties of uranium Offers extensive coverage of both new and established practices for dealing with uranium supplies in nuclear engineering Promotes the documentation of the state-of-the-art processing techniques utilized for uranium and other specialty metals

  3. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium feed; natural uranium feed... (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed....

  4. Sorption/desorption processes of uranium in clayey samples of the Bangombe natural reactor zone, Gabon

    Energy Technology Data Exchange (ETDEWEB)

    Nero, M. del [Inst. de Recherches Subatomiques, CNRS/IN2P3, Strasbourg (France); Salah, S.; Clement, A.; Gauthier-Lafaye, F. [Centre de Geochimie de la Surface, CNRS, Strasbourg (France); Miura, T. [National Lab. for High Energy Physics, Tsukuba-Shi Ibaraki-Ken (Japan)

    1999-07-01

    Experimental studies have been undertaken in order to provide new insights into the relative efficiency of the different mineral phases and sorption processes for the control of U retention in the weathered zones surrounding the natural nuclear reactor at Bangombe (Oklo, Gabon). Clayey and Fe-oxihydroxides rich samples from the oxidizing weathered zones located above the reactor were examined. An experimental study of uranium adsorption/desorption processes in these samples was carried out using a uranium isotope exchange technique in order to estimate the proportion of uranium adsorbed on mineral surfaces. A sequential extraction technique was used to identify the major U-containing minerals in the samples. In the U-rich iron crust rocks close to the reactor, the fraction of total uranium adsorbed at mineral surfaces is small. Extraction experiments reveal that a large part of uranium is associated to Fe-oxihydroxides, to minor P-rich phases, and presumably to Mn-oxihydroxides. A possible mechanism for U retention is an incorporation into the structure of iron oxihydroxides and/or of ferric phosphates occurring as surface precipitates on Fe-oxihydroxides. Traces of autunite-like mineral are also present in the zone. For the clayey samples in the weathering profile, it may be inferred that several processes and minerals contribute significantly to U retention: adsorption processes occurring mainly at clay surfaces, association with traces of Mn-containing carboantes and iron oxihydroxides. A significant proportion of total U is adsorbed at mineral surfaces and is thereby easily accessible to weathering solutions. In a second part of this work, {sup 233}U sorption data obtained on a Fe- and Mn-poor illitic Bangombe sample were modeled using a surface complexation modeling approach. As a first approximation, it was assumed in modeling that uranyl binding occurs at aluminol edge sites of the illite component. The binding constant required for modeling was firstly

  5. 31 CFR 540.309 - Natural uranium.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Natural uranium. 540.309 Section 540... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.309 Natural uranium. The term natural uranium means uranium found...

  6. Designing separation process of radioactive Iodine produced from irradiation of natural uranium

    CERN Document Server

    Nazarie, K

    1999-01-01

    Tehran Research Reactor , one can produce approximately 7 Ci of sup 1 sup 3 sup 1 I for medical purposes. By attention to the sup 1 sup 3 sup 1 I consumption rate in Iran, it is found this amount of sup 1 sup 3 sup 1 I will be enough for our country's demands. On the other hand, by installation of this new method we can produce other very useful radionuclides such as sup 9 sup 9 Mo and sup 1 sup 3 sup 3 Xe in one bath irradiation in the unique production line. sup 1 sup 3 sup 1 I is one of most widely used radionuclide in medical diagnosis and therapy especially for thyroid gland. This is mainly because of its unique nuclear, physical and chemical properties comparing with other radionuclides. In this thesis carrier free sup 1 sup 3 sup 1 I has been separated from natural uranium fission products in the bench scale (mu Ci) and then, sup 1 sup 3 sup 1 I separation and purification systems designed for large scale. Radionuclide, radiochemical and chemical purity of product are compatible with international phar...

  7. URANIUM RECOVERY PROCESS

    Science.gov (United States)

    Bailes, R.H.; Long, R.S.; Olson, R.S.; Kerlinger, H.O.

    1959-02-10

    A method is described for recovering uranium values from uranium bearing phosphate solutions such as are encountered in the manufacture of phosphate fertilizers. The solution is first treated with a reducing agent to obtain all the uranium in the tetravalent state. Following this reduction, the solution is treated to co-precipitate the rcduced uranium as a fluoride, together with other insoluble fluorides, thereby accomplishing a substantially complete recovery of even trace amounts of uranium from the phosphate solution. This precipitate usually takes the form of a complex fluoride precipitate, and after appropriate pre-treatment, the uranium fluorides are leached from this precipitate and rccovered from the leach solution.

  8. Uranium Processing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — An integral part of Y‑12's transformation efforts and a key component of the National Nuclear Security Administration's Uranium Center of Excellence, the Uranium...

  9. Chattanooga shale: uranium recovery by in situ processing

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, D.D.

    1977-04-25

    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.

  10. Natural fractionation of uranium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Noordmann, Janine

    2015-01-24

    The topic of this thesis was the investigation of U (n({sup 238}U) / n({sup 235}U)) isotope variations in nature with a focus on samples (1) that represent the continental crust and its weathering products (i.e. granites, shales and river water) (2) that represent products of hydrothermal alteration on mid-ocean ridges (i.e. altered basalts, carbonate veins and hydrothermal water) and (3) from restricted euxinic basins (i.e. from the water column and respective sediments). The overall goal was to explore the environmental conditions and unravel the mechanisms that fractionate the two most abundant U isotopes, n({sup 238}U) and n({sup 235}U), on Earth.

  11. Innovative Elution Processes for Recovering Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Wai, Chien [Univ. of Idaho, Moscow, ID (United States); Tian, Guoxin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Janke, Christopher [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-05-29

    Utilizing amidoxime-based polymer sorbents for extraction of uranium from seawater has attracted considerable interest in recent years. Uranium collected in the sorbent is recovered typically by elution with an acid. One drawback of acid elution is deterioration of the sorbent which is a significant factor that limits the economic competitiveness of the amidoxime-based sorbent systems for sequestering uranium from seawater. Developing innovative elution processes to improve efficiency and to minimize loss of sorbent capacity become essential in order to make this technology economically feasible for large-scale industrial applications. This project has evaluated several elution processes including acid elution, carbonate elution, and supercritical fluid elution for recovering uranium from amidoxime-based polymer sorbents. The elution efficiency, durability and sorbent regeneration for repeated uranium adsorption- desorption cycles in simulated seawater have been studied. Spectroscopic techniques are used to evaluate chemical nature of the sorbent before and after elution. A sodium carbonate-hydrogen peroxide elution process for effective removal of uranium from amidoxime-based sorbent is developed. The cause of this sodium carbonate and hydrogen peroxide synergistic leaching of uranium from amidoxime-based sorbent is attributed to the formation of an extremely stable uranyl peroxo-carbonato complex. The efficiency of uranium elution by the carbonate-hydrogen peroxide method is comparable to that of the hydrochloric acid elution but damage to the sorbent material is much less for the former. The carbonate- hydrogen peroxide elution also does not need any elaborate step to regenerate the sorbent as those required for hydrochloric acid leaching. Several CO2-soluble ligands have been tested for extraction of uranium from the sorbent in supercritical fluid carbon dioxide. A mixture of hexafluoroacetylacetone and tri-n-butylphosphate shows the best result but uranium

  12. Uranium Biomineralization By Natural Microbial Phosphatase Activities in the Subsurface

    Energy Technology Data Exchange (ETDEWEB)

    Taillefert, Martial [Georgia Tech Research Corporation, Atlanta, GA (United States)

    2015-04-01

    This project investigated the geochemical and microbial processes associated with the biomineralization of radionuclides in subsurface soils. During this study, it was determined that microbial communities from the Oak Ridge Field Research subsurface are able to express phosphatase activities that hydrolyze exogenous organophosphate compounds and result in the non-reductive bioimmobilization of U(VI) phosphate minerals in both aerobic and anaerobic conditions. The changes of the microbial community structure associated with the biomineralization of U(VI) was determined to identify the main organisms involved in the biomineralization process, and the complete genome of two isolates was sequenced. In addition, it was determined that both phytate, the main source of natural organophosphate compounds in natural environments, and polyphosphate accumulated in cells could also be hydrolyzed by native microbial population to liberate enough orthophosphate and precipitate uranium phosphate minerals. Finally, the minerals produced during this process are stable in low pH conditions or environments where the production of dissolved inorganic carbon is moderate. These findings suggest that the biomineralization of U(VI) phosphate minerals is an attractive bioremediation strategy to uranium bioreduction in low pH uranium-contaminated environments. These efforts support the goals of the SBR long-term performance measure by providing key information on "biological processes influencing the form and mobility of DOE contaminants in the subsurface".

  13. The Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFC Focused on Hanford’s 300 Area Uranium Plume Quality Assurance Project Plan

    Energy Technology Data Exchange (ETDEWEB)

    Fix, N. J.

    2008-01-31

    The purpose of the project is to conduct research at an Integrated Field-Scale Research Challenge Site in the Hanford Site 300 Area, CERCLA OU 300-FF-5 (Figure 1), to investigate multi-scale mass transfer processes associated with a subsurface uranium plume impacting both the vadose zone and groundwater. The project will investigate a series of science questions posed for research related to the effect of spatial heterogeneities, the importance of scale, coupled interactions between biogeochemical, hydrologic, and mass transfer processes, and measurements/approaches needed to characterize a mass-transfer dominated system. The research will be conducted by evaluating three (3) different hypotheses focused on multi-scale mass transfer processes in the vadose zone and groundwater, their influence on field-scale U(VI) biogeochemistry and transport, and their implications to natural systems and remediation. The project also includes goals to 1) provide relevant materials and field experimental opportunities for other ERSD researchers and 2) generate a lasting, accessible, and high-quality field experimental database that can be used by the scientific community for testing and validation of new conceptual and numerical models of subsurface reactive transport.

  14. Dry uranium tetrafluoride process preparation using the uranium hexafluoride reconversion process effluents

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, J.B.; Urano de Carvalho, E.F.; Oliveira, F.B.V. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: jbsneto@ipen.br; elitaucf@ipen.br; fabio@ipen.br; Riella, H.G. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)]. E-mail: riella@enq.ufsc.br

    2007-07-01

    It is a well known fact that the use of uranium tetrafluoride allows flexibility in the production of uranium silicide and uranium oxide fuel. To its obtention there are two conventional routes, the one which reduces uranium from the UF{sub 6} hydrolysis solution with stannous chloride, and the hydrofluorination of a solid uranium dioxide. In this work we are introducing a third and a dry way route, mainly utilized to the recovery of uranium from the liquid effluents generated in the uranium hexafluoride reconversion process, at IPEN/CNEN-SP. Working in the liquid phase, this route comprises the recuperation of ammonium fluoride by NH{sub 4}HF{sub 2} precipitation. Working with the solid residues, the crystallized bifluoride is added to the solid UO{sub 2}, which comes from the U miniplates recovery, also to its conversion in a solid state reaction, to obtain UF{sub 4}. That returns to the process of metallic uranium production unity to the U{sub 3}Si{sub 2} obtention. This fuel is considered in IPEN-CNEN/SP as the high density fuel phase for IEA-R1m reactor, which will replace the former low density U{sub 3}O{sub 8}-Al fuel. (author)

  15. Influence of uranium on bacterial communities: a comparison of natural uranium-rich soils with controls.

    Directory of Open Access Journals (Sweden)

    Laure Mondani

    Full Text Available This study investigated the influence of uranium on the indigenous bacterial community structure in natural soils with high uranium content. Radioactive soil samples exhibiting 0.26% - 25.5% U in mass were analyzed and compared with nearby control soils containing trace uranium. EXAFS and XRD analyses of soils revealed the presence of U(VI and uranium-phosphate mineral phases, identified as sabugalite and meta-autunite. A comparative analysis of bacterial community fingerprints using denaturing gradient gel electrophoresis (DGGE revealed the presence of a complex population in both control and uranium-rich samples. However, bacterial communities inhabiting uraniferous soils exhibited specific fingerprints that were remarkably stable over time, in contrast to populations from nearby control samples. Representatives of Acidobacteria, Proteobacteria, and seven others phyla were detected in DGGE bands specific to uraniferous samples. In particular, sequences related to iron-reducing bacteria such as Geobacter and Geothrix were identified concomitantly with iron-oxidizing species such as Gallionella and Sideroxydans. All together, our results demonstrate that uranium exerts a permanent high pressure on soil bacterial communities and suggest the existence of a uranium redox cycle mediated by bacteria in the soil.

  16. Study of Natural Background Radiation around Gurvanbulag Uranium Deposit Area

    Science.gov (United States)

    Enkhbat, N.; Norov, N.; Bat-Erdene, B.; Khuukhenkhuu, G.; Otgooloi, B.

    2009-03-01

    In this work, we will show the study of natural background radiation level around the Gurvanbulag (GB) uranium deposit area in the eastern part of Mongolia. We collected environmental soil samples from 102 points around GB Uranium deposit. Collected samples were measured by HPGe gamma spectrometer at Nuclear Research Center, National University of Mongolia. The averaged activity concentrations of Ra-226, Th-232, K-40, and Cs-137 were 37.1, 29, 939, and 17.7 Bq/kg, respectively.

  17. The separation of uranium ions by natural and modified diatomite from aqueous solution.

    Science.gov (United States)

    Sprynskyy, Myroslav; Kovalchuk, Iryna; Buszewski, Bogusław

    2010-09-15

    In this work the natural and the surfactant modified diatomite has been tested for ability to remove uranium ions from aqueous solutions. Such controlling factors of the adsorption process as initial uranium concentration, pH, contact time and ionic strength have been investigated. Effect of ionic strength of solution has been examined using the solutions of NaCl, Na(2)CO(3) and K(2)SO(4). The pseudo-first order and the pseudo-second order models have been used to analyze the adsorption kinetic results, whereas the Langmuir and the Freundlich isotherms have been used to the equilibrium adsorption data. The effects of the adsorbent modification as well as uranium adsorption on the diatomite surface have been studied using X-ray powder diffraction, scanning electron microscopy and FTIR spectroscopy. The maximum adsorption capacities of the natural and the modified diatomite towards uranium were 25.63 micromol/g and 667.40 micromol/g, respectively. The desorptive solutions of HCl, NaOH, Na(2)CO(3), K(2)SO(4), CaCO(3), humic acid, cool and hot water have been tested to recover uranium from the adsorbent. The highest values of uranium desorption (86%) have been reached using 0.1M HCl. Copyright 2010 Elsevier B.V. All rights reserved.

  18. Gas Cooled, Natural Uranium, D20 Moderated Power Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Dahlberg, R.C.; Beasley, E.G.; DeBoer, T.K.; Evans, T.C.; Molino, D.F.; Rothwell, W.S.; Slivka, W.R.

    1956-08-01

    The attractiveness of a helium cooled, heavy water moderated, natural uranium central station power plant has been investigated. A fuel element has been devised which allows the D20 to be kept at a low pressure while the exit gas temperature is high. A preliminary cost analysis indicates that, using currently available materials, competitive nuclear power in foreign countries is possible.

  19. 49 CFR 173.434 - Activity-mass relationships for uranium and natural thorium.

    Science.gov (United States)

    2010-10-01

    ... natural thorium. 173.434 Section 173.434 Transportation Other Regulations Relating to Transportation....434 Activity-mass relationships for uranium and natural thorium. The table of activity-mass relationships for uranium and natural thorium are as follows: Thorium and uranium enrichment 1(Wt% 235 U...

  20. 10 CFR 40.66 - Requirements for advance notice of export shipments of natural uranium.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Requirements for advance notice of export shipments of natural uranium. 40.66 Section 40.66 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF SOURCE... natural uranium. (a) Each licensee authorized to export natural uranium, other than in the form of ore...

  1. 77 FR 53236 - Proposed International Isotopes Fluorine Extraction Process and Depleted Uranium Deconversion...

    Science.gov (United States)

    2012-08-31

    ... COMMISSION Proposed International Isotopes Fluorine Extraction Process and Depleted Uranium Deconversion... International Isotopes Fluorine Extraction Process and Depleted Uranium Deconversion Plant (INIS) in Lea County... construction, operation, and decommissioning of a fluorine extraction and depleted uranium...

  2. Behaviour of uranium during processing of Egyptian monazite

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Rehim, A.M. [Alexandria Univ., Shallalat, Alexandria (Egypt)

    2000-07-01

    The present work deals with the study of the behaviour of uranium during alkaline processing of Egyptian monazite, followed by selective separation of thorium and uranium from lanthanides by leaching of the hydroxide cake with ammonium carbonate solutions. This method is based on the dissolution of thorium and uranium hydroxides in ammonium carbonate solutions in the form of soluble ammonium thorium and uranyl carbonate complexes, while the lanthanides hydroxides form sparingly soluble double carbonates. The obtained carbonate solutions, containing carbonate complexes of thorium and uranium are decomposed with steam in steel autoclaves. Uranium is completely recovered with thorium (99.7%) by alkaline processing of monazite concentrate in ball mill autoclaves at 150{sup 0}C during 2.5 hours. The selective carbonate autoclave processing of hydroxide cake with ammonium carbonate-bicarbonate solutions show that high recovery of uranium (94.7%) with complete recovery of thorium (99.4%) and their separation from lanthanides are attained at 70-80{sup o}C, pressure 5-10 atm during 1h. The decomposition of carbonate complexes of thorium and uranium is favourably carried out in autoclaves at 120{sup o}C and steam pressure 2 atm during 10 min. Uranium is nearly completely recovered (98.4%) with thorium (99.8%) in the thorium concentrate produced. Meanwhile, the recovery of lanthanides is low and does not exceed 1.1%. The produced thorium concentrate contains 67.8% Th and 4.6% U. (author)

  3. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume January 2011 to January 2012

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, John M.; Bjornstad, Bruce N.; Christensen, John N.; Conrad, Mark S.; Fredrickson, Jim K.; Freshley, Mark D.; Haggerty, Roy; Hammond, Glenn E.; Kent, Douglas B.; Konopka, Allan; Lichtner, Peter C.; Liu, Chongxuan; McKinley, James P.; Murray, Christopher J.; Rockhold, Mark L.; Rubin, Yoram; Vermeul, Vincent R.; Versteeg, Roelof J.; Zheng, Chunmiao

    2012-03-05

    The Integrated Field Research Challenge (IFRC) at the Hanford Site 300 Area uranium (U) plume addresses multi-scale mass transfer processes in a complex subsurface biogeochemical setting where groundwater and riverwater interact. A series of forefront science questions on reactive mass transfer motivates research. These questions relate to the effect of spatial heterogeneities; the importance of scale; coupled interactions between biogeochemical, hydrologic, and mass transfer processes; and measurements and approaches needed to characterize and model a mass-transfer dominated biogeochemical system. The project was initiated in February 2007, with CY 2007, CY 2008, CY 2009, and CY 2010 progress summarized in preceding reports. A project peer review was held in March 2010, and the IFRC project acted upon all suggestions and recommendations made in consequence by reviewers and SBR/DOE. These responses have included the development of 'Modeling' and 'Well-Field Mitigation' plans that are now posted on the Hanford IFRC web-site, and modifications to the IFRC well-field completed in CY 2011. The site has 35 instrumented wells, and an extensive monitoring system. It includes a deep borehole for microbiologic and biogeochemical research that sampled the entire thickness of the unconfined 300 A aquifer. Significant, impactful progress has been made in CY 2011 including: (i) well modifications to eliminate well-bore flows, (ii) hydrologic testing of the modified well-field and upper aquifer, (iii) geophysical monitoring of winter precipitation infiltration through the U-contaminated vadose zone and spring river water intrusion to the IFRC, (iv) injection experimentation to probe the lower vadose zone and to evaluate the transport behavior of high U concentrations, (v) extended passive monitoring during the period of water table rise and fall, and (vi) collaborative down-hole experimentation with the PNNL SFA on the biogeochemistry of the 300 A Hanford

  4. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, John M.; Bjornstad, Bruce N.; Christensen, John N.; Conrad, Mark E.; Fredrickson, Jim K.; Freshley, Mark D.; Haggerty, Roy; Hammon, Glenn; Kent, Douglas B.; Konopka, Allan; Lichtner, Peter C.; Liu, Chongxuan; McKinley, James P.; Murray, Christopher J.; Rockhold, Mark L.; Rubin, Yoram; Vermeul, Vincent R.; Versteeg, Roelof J.; Ward, Anderson L.; Zheng, Chunmiao

    2010-02-01

    The Integrated Field-Scale Subsurface Research Challenge (IFRC) at the Hanford Site 300 Area uranium (U) plume addresses multi-scale mass transfer processes in a complex hydrogeologic setting where groundwater and riverwater interact. A series of forefront science questions on mass transfer are posed for research which relate to the effect of spatial heterogeneities; the importance of scale; coupled interactions between biogeochemical, hydrologic, and mass transfer processes; and measurements and approaches needed to characterize and model a mass-transfer dominated system. The project was initiated in February 2007, with CY 2007 and CY 2008 progress summarized in preceding reports. The site has 35 instrumented wells, and an extensive monitoring system. It includes a deep borehole for microbiologic and biogeochemical research that sampled the entire thickness of the unconfined 300 A aquifer. Significant, impactful progress has been made in CY 2009 with completion of extensive laboratory measurements on field sediments, field hydrologic and geophysical characterization, four field experiments, and modeling. The laboratory characterization results are being subjected to geostatistical analyses to develop spatial heterogeneity models of U concentration and chemical, physical, and hydrologic properties needed for reactive transport modeling. The field experiments focused on: (1) physical characterization of the groundwater flow field during a period of stable hydrologic conditions in early spring, (2) comprehensive groundwater monitoring during spring to characterize the release of U(VI) from the lower vadose zone to the aquifer during water table rise and fall, (3) dynamic geophysical monitoring of salt-plume migration during summer, and (4) a U reactive tracer experiment (desorption) during the fall. Geophysical characterization of the well field was completed using the down-well Electrical Resistance Tomography (ERT) array, with results subjected to robust

  5. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume January 2010 to January 2011

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, John M.; Bjornstad, Bruce N.; Christensen, John N.; Conrad, Mark S.; Fredrickson, Jim K.; Freshley, Mark D.; Haggerty, Roy; Hammond, Glenn E.; Kent, Douglas B.; Konopka, Allan; Lichtner, Peter C.; Liu, Chongxuan; McKinley, James P.; Murray, Christopher J.; Rockhold, Mark L.; Rubin, Yoram; Vermeul, Vincent R.; Versteeg, Roelof J.; Ward, Anderson L.; Zheng, Chunmiao

    2011-02-01

    The Integrated Field Research Challenge (IFRC) at the Hanford Site 300 Area uranium (U) plume addresses multi-scale mass transfer processes in a complex subsurface hydrogeologic setting where groundwater and riverwater interact. A series of forefront science questions on reactive mass transfer focus research. These questions relate to the effect of spatial heterogeneities; the importance of scale; coupled interactions between biogeochemical, hydrologic, and mass transfer processes; and measurements and approaches needed to characterize and model a mass-transfer dominated system. The project was initiated in February 2007, with CY 2007, CY 2008, and CY 2009 progress summarized in preceding reports. A project peer review was held in March 2010, and the IFRC project has responded to all suggestions and recommendations made in consequence by reviewers and SBR/DOE. These responses have included the development of “Modeling” and “Well-Field Mitigation” plans that are now posted on the Hanford IFRC web-site. The site has 35 instrumented wells, and an extensive monitoring system. It includes a deep borehole for microbiologic and biogeochemical research that sampled the entire thickness of the unconfined 300 A aquifer. Significant, impactful progress has been made in CY 2010 including the quantification of well-bore flows in the fully screened wells and the testing of means to mitigate them; the development of site geostatistical models of hydrologic and geochemical properties including the distribution of U; developing and parameterizing a reactive transport model of the smear zone that supplies contaminant U to the groundwater plume; performance of a second passive experiment of the spring water table rise and fall event with a associated multi-point tracer test; performance of downhole biogeochemical experiments where colonization substrates and discrete water and gas samplers were deployed to the lower aquifer zone; and modeling of past injection experiments for

  6. Biogeochemical Processes Regulating the Mobility of Uranium in Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Belli, Keaton M.; Taillefert, Martial

    2016-07-01

    This book chapters reviews the latest knowledge on the biogeochemical processes regulating the mobility of uranium in sediments. It contains both data from the literature and new data from the authors.

  7. Uranium-series radionuclides as tracers of geochemical processes in Long Island Sound. [Natural /sup 210/Pb tracer study of estuarine geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Benninger, L.K.

    1976-05-01

    An estuary can be visualized as a membrane between land and the deep ocean, and the understanding of the estuarine processes which determine the permeability of this membrane to terrigenous materials is necessary for the estimation of fluxes of these materials to the oceans. Natural radionuclides are useful probes into estuarine geochemistry because of the time-dependent relationships among them and because, as analogs of stable elements, they are much less subject to contamination during sampling and analysis. In this study the flux of heavy metals through Long Island Sound is considered in light of the material balance for excess /sup 210/Pb, and analyses of concurrent seston and water samples from central Long Island Sound are used to probe the internal workings of the estuary.

  8. Occupational exposures to uranium: processes, hazards, and regulations

    Energy Technology Data Exchange (ETDEWEB)

    Stoetzel, G.A.; Fisher, D.R.; McCormack, W.D.; Hoenes, G.R.; Marks, S.; Moore, R.H.; Quilici, D.G.; Breitenstein, B.D.

    1981-04-01

    The United States Uranium Registry (USUR) was formed in 1978 to investigate potential hazards from occupational exposure to uranium and to assess the need for special health-related studies of uranium workers. This report provides a summary of Registry work done to date. The history of the uranium industry is outlined first, and the current commercial uranium industry (mining, milling, conversion, enrichment, and fuel fabrication) is described. This description includes information on basic processes and areas of greatest potential radiological exposure. In addition, inactive commercial facilities and other uranium operations are discussed. Regulation of the commercial production industry for uranium fuel is reported, including the historic development of regulations and the current regulatory agencies and procedures for each phase of the industry. A review of radiological health practices in the industry - facility monitoring, exposure control, exposure evaluation, and record-keeping - is presented. A discussion of the nonradiological hazards of the industry is provided, and the final section describes the tissue program developed as part of the Registry.

  9. Uranium mining in Virginia: scientific, technical, environmental, human health and safety, and regulatory aspects of uranium mining and processing in Virginia

    National Research Council Canada - National Science Library

    Committee on Uranium Mining in Virginia; Committee on Earth Resources; National Research Council

    2012-01-01

    .... Uranium Mining in Virginia examines the scientific, technical, environmental, human health and safety, and regulatory aspects of uranium mining, milling, and processing as they relate to the Common...

  10. Natural Language Processing.

    Science.gov (United States)

    Chowdhury, Gobinda G.

    2003-01-01

    Discusses issues related to natural language processing, including theoretical developments; natural language understanding; tools and techniques; natural language text processing systems; abstracting; information extraction; information retrieval; interfaces; software; Internet, Web, and digital library applications; machine translation for…

  11. 49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.

    Science.gov (United States)

    2010-10-01

    ... uranium or thorium. 173.426 Section 173.426 Transportation Other Regulations Relating to Transportation....426 Excepted packages for articles containing natural uranium or thorium. A manufactured article in... or natural thorium, and its packaging, are excepted from the requirements in this subchapter...

  12. Process for recovering uranium from waste hydrocarbon oils containing the same. [Uranium contaminated lubricating oils from gaseous diffusion compressors

    Science.gov (United States)

    Conrad, M.C.; Getz, P.A.; Hickman, J.E.; Payne, L.D.

    1982-06-29

    The invention is a process for the recovery of uranium from uranium-bearing hydrocarbon oils containing carboxylic acid as a degradation product. In one aspect, the invention comprises providing an emulsion of water and the oil, heating the same to a temperature effecting conversion of the emulsion to an organic phase and to an acidic aqueous phase containing uranium carboxylate, and recovering the uranium from the aqueous phase. The process is effective, simple and comparatively inexpensive. It avoids the use of toxic reagents and the formation of undesirable intermediates.

  13. Validation of gamma-ray detection techniques for safeguards monitoring at natural uranium conversion facilities

    Science.gov (United States)

    Dewji, S. A.; Lee, D. L.; Croft, S.; Hertel, N. E.; Chapman, J. A.; McElroy, R. D.; Cleveland, S.

    2016-07-01

    Recent IAEA circulars and policy papers have sought to implement safeguards when any purified aqueous uranium solution or uranium oxides suitable for isotopic enrichment or fuel fabrication exists. Under the revised policy, IAEA Policy Paper 18, the starting point for nuclear material under safeguards was reinterpreted, suggesting that purified uranium compounds should be subject to safeguards procedures no later than the first point in the conversion process. In response to this technical need, a combination of simulation models and experimental measurements were employed to develop and validate concepts of nondestructive assay monitoring systems in a natural uranium conversion plant (NUCP). In particular, uranyl nitrate (UO2(NO3)2) solution exiting solvent extraction was identified as a key measurement point (KMP), where gamma-ray spectroscopy was selected as the process monitoring tool. The Uranyl Nitrate Calibration Loop Equipment (UNCLE) facility at Oak Ridge National Laboratory was employed to simulate the full-scale operating conditions of a purified uranium-bearing aqueous stream exiting the solvent extraction process in an NUCP. Nondestructive assay techniques using gamma-ray spectroscopy were evaluated to determine their viability as a technical means for drawing safeguards conclusions at NUCPs, and if the IAEA detection requirements of 1 significant quantity (SQ) can be met in a timely way. This work investigated gamma-ray signatures of uranyl nitrate circulating in the UNCLE facility and evaluated various gamma-ray detector sensitivities to uranyl nitrate. These detector validation activities include assessing detector responses to the uranyl nitrate gamma-ray signatures for spectrometers based on sodium iodide, lanthanum bromide, and high-purity germanium detectors. The results of measurements under static and dynamic operating conditions at concentrations ranging from 10-90 g U/L of natural uranyl nitrate are presented. A range of gamma-ray lines is

  14. Validation of gamma-ray detection techniques for safeguards monitoring at natural uranium conversion facilities

    Energy Technology Data Exchange (ETDEWEB)

    Dewji, S.A., E-mail: dewjisa@ornl.gov [Oak Ridge National Laboratory, 1 Bethel Valley Road, MS-6335, Oak Ridge, TN 37831-6335 (United States); Lee, D.L.; Croft, S. [Oak Ridge National Laboratory, 1 Bethel Valley Road, MS-6335, Oak Ridge, TN 37831-6335 (United States); Hertel, N.E. [Oak Ridge National Laboratory, 1 Bethel Valley Road, MS-6335, Oak Ridge, TN 37831-6335 (United States); Nuclear and Radiological Engineering Program, Georgia Institute of Technology, 770 State Street, Atlanta, GA 30332-0745 (United States); Chapman, J.A.; McElroy, R.D.; Cleveland, S. [Oak Ridge National Laboratory, 1 Bethel Valley Road, MS-6335, Oak Ridge, TN 37831-6335 (United States)

    2016-07-01

    Recent IAEA circulars and policy papers have sought to implement safeguards when any purified aqueous uranium solution or uranium oxides suitable for isotopic enrichment or fuel fabrication exists. Under the revised policy, IAEA Policy Paper 18, the starting point for nuclear material under safeguards was reinterpreted, suggesting that purified uranium compounds should be subject to safeguards procedures no later than the first point in the conversion process. In response to this technical need, a combination of simulation models and experimental measurements were employed to develop and validate concepts of nondestructive assay monitoring systems in a natural uranium conversion plant (NUCP). In particular, uranyl nitrate (UO{sub 2}(NO{sub 3}){sub 2}) solution exiting solvent extraction was identified as a key measurement point (KMP), where gamma-ray spectroscopy was selected as the process monitoring tool. The Uranyl Nitrate Calibration Loop Equipment (UNCLE) facility at Oak Ridge National Laboratory was employed to simulate the full-scale operating conditions of a purified uranium-bearing aqueous stream exiting the solvent extraction process in an NUCP. Nondestructive assay techniques using gamma-ray spectroscopy were evaluated to determine their viability as a technical means for drawing safeguards conclusions at NUCPs, and if the IAEA detection requirements of 1 significant quantity (SQ) can be met in a timely way. This work investigated gamma-ray signatures of uranyl nitrate circulating in the UNCLE facility and evaluated various gamma-ray detector sensitivities to uranyl nitrate. These detector validation activities include assessing detector responses to the uranyl nitrate gamma-ray signatures for spectrometers based on sodium iodide, lanthanum bromide, and high-purity germanium detectors. The results of measurements under static and dynamic operating conditions at concentrations ranging from 10–90 g U/L of natural uranyl nitrate are presented. A range of

  15. Evidence of isotopic fractionation of natural uranium in cultured human cells

    Science.gov (United States)

    Paredes, Eduardo; Avazeri, Emilie; Malard, Véronique; Vidaud, Claude; Reiller, Pascal E.; Ortega, Richard; Nonell, Anthony; Isnard, Hélène; Chartier, Frédéric; Bresson, Carole

    2016-12-01

    The study of the isotopic fractionation of endogen elements and toxic heavy metals in living organisms for biomedical applications, and for metabolic and toxicological studies, is a cutting-edge research topic. This paper shows that human neuroblastoma cells incorporated small amounts of uranium (U) after exposure to 10 µM natural U, with preferential uptake of the 235U isotope with regard to 238U. Efforts were made to develop and then validate a procedure for highly accurate n(238U)/n(235U) determinations in microsamples of cells. We found that intracellular U is enriched in 235U by 0.38 ± 0.13‰ (2σ, n = 7) relative to the exposure solutions. These in vitro experiments provide clues for the identification of biological processes responsible for uranium isotopic fractionation and link them to potential U incorporation pathways into neuronal cells. Suggested incorporation processes are a kinetically controlled process, such as facilitated transmembrane diffusion, and the uptake through a high-affinity uranium transport protein involving the modification of the uranyl (UO22+) coordination sphere. These findings open perspectives on the use of isotopic fractionation of metals in cellular models, offering a probe to track uptake/transport pathways and to help decipher associated cellular metabolic processes.

  16. Uranium isotopic data in uraninite spent fuel from the Bangombe natural nuclear reactor (Gabon) and its surroundings

    Science.gov (United States)

    Fernandez-Diaz; Quejido; Crespo; Perez del Villar L; Martin-Sanchez; Lozano

    2000-07-01

    In the framework of the "Oklo-Natural Analogue Phase II" Project, uraninite from the Bangombe natural reactor and samples from its host rock were analyzed to determine their uranium isotopic composition by thermal ionisation mass spectrometry, inductively coupled plasma mass spectrometry and alpha spectrometry. There were several objectives for this work: (i) to validate the 235U/238U isotopic ratios obtained by these techniques; (ii) to test the use of the 235U/238U ratio of uraninite as a tracer of migration/retention processes of uranium from the source term to the far field; (iii) to evaluate the most recent migration/retention processes of uranium in the system by U-series disequilibrium.

  17. Uranium isotopic data in uraninite spent fuel from the Bangombe natural nuclear reactor (Gabon) and its surroundings

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Diaz, M.; Quejido, A.J.; Crespo, M.T.; Villar, L.P. del; Martin-Sanchez, A. E-mail: ams@unex.es; Lozano, J.C

    2000-07-15

    In the framework of the 'Oklo-Natural Analogue Phase II' Project, uraninite from the Bangombe natural reactor and samples from its host rock were analyzed to determine their uranium isotopic composition by thermal ionisation mass spectrometry, inductively coupled plasma mass spectrometry and alpha spectrometry. There were several objectives for this work: (i) to validate the {sup 235}U/{sup 238}U isotopic ratios obtained by these techniques; (ii) to test the use of the {sup 235}U/{sup 238}U ratio of uraninite as a tracer of migration/retention processes of uranium from the source term to the far field; (iii) to evaluate the most recent migration/retention processes of uranium in the system by U-series disequilibrium.

  18. Exposure assessment of natural uranium from drinking water.

    Science.gov (United States)

    Jakhu, Rajan; Mehra, Rohit; Mittal, H M

    2016-12-08

    The uranium concentration in the drinking water of the residents of the Jaipur and Ajmer districts of Rajasthan has been measured for exposure assessment. The daily intake of uranium from the drinking water for the residents of the study area is found to vary from 0.4 to 123.9 μg per day. For the average uranium ingestion rate of 35.2 μg per day for a long term exposure period of 60 years, estimations have been made for the retention of uranium in different body organs and its excretion with time using ICRP's biokinetic model of uranium. Radioactive and chemical toxicity of uranium has been reported and discussed in detail in the present manuscript.

  19. Mining and processing of uranium ores at the Streltsovsky ore field

    Energy Technology Data Exchange (ETDEWEB)

    Ovseytchuk, V.A.; Litvinenko, V.G.; Kultishev, V.I. [Joint Stock Company, Priargunsky Industrial Mining and Chemical Union, Krasnokamensk, Chita Region (Russian Federation)

    2000-07-01

    The uranium deposits of Streltsovsky ore fields provide raw materials for Russian nuclear industry. For this region, it is important to achieve continued and increased activities in the recovery of mineral resources of uranium. Similarly, maintaining the mining and processing of uranium ores ensures the supply of raw materials for the nuclear industry. With the current operations, increasing the mining and processing activities would increase the cost of production of uranium oxides due to decreasing grades of ore body. After a review of the existing economic, technological and natural factors, a solution was proposed based on the joint application of underground mining and ore enrichment and processing with the help of hydrometallurgical process, in-situ leaching. Reduction of operation coasts and creation of radiation-safe working conditions could be achieved with the application of these systems involving concrete hardening in the mines and in-situ leaching of ore. With the help of economic-mathematical modeling, methods for rational application of various technologies could be determined and their processing parameters were specified. A reduction of coasts could be obtained and favorable conditions could be established for improvement in the treatment of lower grade ores by heap leaching. Application of purification of mine waters and tailing pond reduces the influence of the radiation and the impact on the natural environment. (author)

  20. Applications of Ecological Engineering Remedies for Uranium Processing Sites, USA

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, William [Navarro Research and Engineering

    2016-05-23

    The U.S. Department of Energy (USDOE) is responsible for remediation of environmental contamination and long-term stewardship of sites associated with the legacy of nuclear weapons production during the Cold War in the United States. Protection of human health and the environment will be required for hundreds or even thousands of years at many legacy sites. USDOE continually evaluates and applies advances in science and technology to improve the effectiveness and sustainability of surface and groundwater remedies (USDOE 2011). This paper is a synopsis of ecological engineering applications that USDOE is evaluating to assess the effectiveness of remedies at former uranium processing sites in the southwestern United States. Ecological engineering remedies are predicated on the concept that natural ecological processes at legacy sites, once understood, can be beneficially enhanced or manipulated. Advances in tools for characterizing key processes and for monitoring remedy performance are demonstrating potential. We present test cases for four ecological engineering remedies that may be candidates for international applications.

  1. Purification of wet process phosphoric acid by decreasing iron and uranium using white silica sand

    Energy Technology Data Exchange (ETDEWEB)

    El-Bayaa, A.A., E-mail: amina.elbayaa@yahoo.com [Chemistry Department, Faculty of Science, Al-Azhar University (Girls), Nasr City, Cairo (Egypt); Badawy, N.A.; Gamal, A.M.; Zidan, I.H.; Mowafy, A.R. [Chemistry Department, Faculty of Science, Al-Azhar University (Girls), Nasr City, Cairo (Egypt)

    2011-06-15

    Natural white silica sand as an adsorbent has been developed to reduce the concentration of iron and uranium ions as inorganic impurities in crude Egyptian phosphoric acid. Several parameters such as adsorbate concentration, adsorbent dose, volume to weight ratio and temperature, were investigated. Equilibrium isotherm studies were used to evaluate the maximum sorption capacity of adsorbent. Thermodynamic parameters showed the exothermic nature of the process and the negative entropy reflects the affinity of the adsorbent material towards each metal ion.

  2. Modified sodium diuranate process for the recovery of uranium from uranium hexafluoride transport cylinder wash solution

    Science.gov (United States)

    Meredith, Austin Dean

    Uranium hexafluoride (UF6) containment cylinders must be emptied and washed every five years in order to undergo recertification, according to ANSI standards. During the emptying of the UF6 from the cylinders, a thin residue, or heel, of UF6 is left behind. This heel must be removed in order for recertification to take place. To remove it, the inside of the containment cylinder is washed with acid and the resulting solution generally contains three or four kilograms of uranium. Thus, before the liquid solution can be disposed of, the uranium must be separated. A modified sodium diuranate (SDU) uranium recovery process was studied to support development of a commercial process. This process was sought to ensure complete uranium recovery, at high purity, in order that it might be reused in the nuclear fuel cycle. An experimental procedure was designed and carried out in order to verify the effectiveness of the commercial process in a laboratory setting. The experiments involved a small quantity of dried UO2F2 powder that was dosed with 3wt% FeF3 and was dissolved in water to simulate the cylinder wash solution. Each experiment series started with a measured amount of this powder mixture which was dissolved in enough water to make a solution containing about 120 gmU/liter. The experiments involved validating the modified SDU extraction process. A potassium diuranate (KDU) process was also attempted. Very little information exists regarding such a process, so the task was undertaken to evaluate its efficacy and determine whether a potassium process yields any significant differences or advantages as compared to a sodium process. However, the KDU process ultimately proved ineffective and was abandoned. Each of the experiments was organized into a series of procedures that started with the UO2F2 powder being dissolved in water, and proceeded through the steps needed to first convert the uranium to a diuranate precipitate, then to a carbonate complex solution, and finally

  3. Determination of natural uranium, thorium and radium isotopes in water and soil samples by alpha spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Le Cong; Tao, Chau Van; Thong, Luong Van; Linh, Duong Mong [University of Science Ho Chi Minh City (Viet Nam). Faculty of Physics and Engineering Physics; Dong, Nguyen Van [University of Science Ho Chi Minh City (Viet Nam). Faculty of Chemistry

    2011-08-15

    In this study, a simple procedure for the determination of natural uranium, thorium and radium isotopes in water and soil samples by alpha spectroscopy is described. This procedure allows a sequential extraction polonium, uranium, thorium and radium radionuclides from the same sample in two to three days. It was tested and validated with the analysis of certified reference materials from the IAEA. (orig.)

  4. Natural Language Processing

    OpenAIRE

    Preeti; BrahmaleenKaurSidhu

    2013-01-01

    Natural language processing (NLP) work began more than sixty years ago; it is a field of computer science and linguistics devoted to creating computer systems that use human (natural) language. Natural Language Processing holds great promise for making computer interfaces that are easier to use for people, since people will be able to talk to the computer in their own language, rather than learn a specialized language of computer commands. Natural Language processing techniques can make possi...

  5. Uranium Bio-accumulation and Cycling as revealed by Uranium Isotopes in Naturally Reduced Sediments from the Upper Colorado River Basin

    Science.gov (United States)

    Lefebvre, Pierre; Noël, Vincent; Jemison, Noah; Weaver, Karrie; Bargar, John; Maher, Kate

    2016-04-01

    Uranium (U) groundwater contamination following oxidized U(VI) releases from weathering of mine tailings is a major concern at numerous sites across the Upper Colorado River Basin (CRB), USA. Uranium(IV)-bearing solids accumulated within naturally reduced zones (NRZs) characterized by elevated organic carbon and iron sulfide compounds. Subsequent re-oxidation of U(IV)solid to U(VI)aqueous then controls the release to groundwater and surface water, resulting in plume persistence and raising public health concerns. Thus, understanding the extent of uranium oxidation and reduction within NRZs is critical for assessing the persistence of the groundwater contamination. In this study, we measured solid-phase uranium isotope fractionation (δ238/235U) of sedimentary core samples from four study sites (Shiprock, NM, Grand Junction, Rifle and Naturita, CO) using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). We observe a strong correlation between U accumulation and the extent of isotopic fractionation, with Δ238U up to +1.8 ‰ between uranium-enriched and low concentration zones. The enrichment in the heavy isotopes within the NRZs appears to be especially important in the vadose zone, which is subject to variations in water table depth. According to previous studies, this isotopic signature is consistent with biotic reduction processes associated with metal-reducing bacteria. Positive correlations between the amount of iron sulfides and the accumulation of reduced uranium underline the importance of sulfate-reducing conditions for U(IV) retention. Furthermore, the positive fractionation associated with U reduction observed across all sites despite some variations in magnitude due to site characteristics, shows a regional trend across the Colorado River Basin. The maximum extent of 238U enrichment observed in the NRZ proximal to the water table further suggests that the redox cycling of uranium, with net release of U(VI) to the groundwater by

  6. Model of a Generic Natural Uranium Conversion Plant ? Suggested Measures to Strengthen International Safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Raffo-Caiado, Ana Claudia [ORNL; Begovich, John M [ORNL; Ferrada, Juan J [ORNL

    2009-11-01

    This is the final report that closed a joint collaboration effort between DOE and the National Nuclear Energy Commission of Brazil (CNEN). In 2005, DOE and CNEN started a collaborative effort to evaluate measures that can strengthen the effectiveness of international safeguards at a natural uranium conversion plant (NUCP). The work was performed by DOE s Oak Ridge National Laboratory and CNEN. A generic model of a NUCP was developed and typical processing steps were defined. Advanced instrumentation and techniques for verification purposes were identified and investigated. The scope of the work was triggered by the International Atomic Energy Agency s 2003 revised policy concerning the starting point of safeguards at uranium conversion facilities. Prior to this policy only the final products of the uranium conversion plant were considered to be of composition and purity suitable for use in the nuclear fuel cycle and therefore, subject to the IAEA safeguards control. DOE and CNEN have explored options for implementing the IAEA policy, although Brazil understands that the new policy established by the IAEA is beyond the framework of the Quadripartite Agreement of which it is one of the parties, together with Argentina, the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) and the IAEA. Two technical papers on this subject were published at the 2005 and 2008 INMM Annual Meetings.

  7. Model of a Generic Natural Uranium Conversion Plant ? Suggested Measures to Strengthen International Safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Raffo-Caiado, Ana Claudia [ORNL; Begovich, John M [ORNL; Ferrada, Juan J [ORNL

    2009-11-01

    This is the final report that closed a joint collaboration effort between DOE and the National Nuclear Energy Commission of Brazil (CNEN). In 2005, DOE and CNEN started a collaborative effort to evaluate measures that can strengthen the effectiveness of international safeguards at a natural uranium conversion plant (NUCP). The work was performed by DOE s Oak Ridge National Laboratory and CNEN. A generic model of a NUCP was developed and typical processing steps were defined. Advanced instrumentation and techniques for verification purposes were identified and investigated. The scope of the work was triggered by the International Atomic Energy Agency s 2003 revised policy concerning the starting point of safeguards at uranium conversion facilities. Prior to this policy only the final products of the uranium conversion plant were considered to be of composition and purity suitable for use in the nuclear fuel cycle and therefore, subject to the IAEA safeguards control. DOE and CNEN have explored options for implementing the IAEA policy, although Brazil understands that the new policy established by the IAEA is beyond the framework of the Quadripartite Agreement of which it is one of the parties, together with Argentina, the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) and the IAEA. Two technical papers on this subject were published at the 2005 and 2008 INMM Annual Meetings.

  8. 76 FR 24871 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2011-05-03

    ... Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites AGENCY: Department of... from eligible active uranium and thorium processing site licensees for reimbursement under Title X of...). Title X requires DOE to reimburse eligible uranium and thorium licensees for certain costs...

  9. 77 FR 3460 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2012-01-24

    ... Uranium and Thorium Processing Sites AGENCY: Department of Energy. ACTION: Notice of the acceptance of... (DOE) acceptance of claims in FY 2012 from eligible active uranium and thorium processing site... uranium and thorium licensees for certain costs of decontamination, decommissioning, reclamation,...

  10. 75 FR 71677 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2010-11-24

    ... Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites AGENCY: Department of... uranium and thorium processing site licensees for reimbursement under Title X of the Energy Policy Act of... requires DOE to reimburse eligible uranium and thorium licensees for certain costs of...

  11. 76 FR 30696 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2011-05-26

    ... Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites AGENCY: Department of... eligible active uranium and thorium processing site licensees for reimbursement under Title X of the Energy... requires DOE to reimburse eligible uranium and thorium licensees for certain costs of...

  12. Uranium Biomineralization by Natural Microbial Phosphatase Activities in the Subsurface

    Energy Technology Data Exchange (ETDEWEB)

    Sobecky, Patricia A. [Univ. of Alabama, Tuscaloosa, AL (United States)

    2015-04-06

    In this project, inter-disciplinary research activities were conducted in collaboration among investigators at The University of Alabama (UA), Georgia Institute of Technology (GT), Lawrence Berkeley National Laboratory (LBNL), Brookhaven National Laboratory (BNL), the DOE Joint Genome Institute (JGI), and the Stanford Synchrotron Radiation Light source (SSRL) to: (i) confirm that phosphatase activities of subsurface bacteria in Area 2 and 3 from the Oak Ridge Field Research Center result in solid U-phosphate precipitation in aerobic and anaerobic conditions; (ii) investigate the eventual competition between uranium biomineralization via U-phosphate precipitation and uranium bioreduction; (iii) determine subsurface microbial community structure changes of Area 2 soils following organophosphate amendments; (iv) obtain the complete genome sequences of the Rahnella sp. Y9-602 and the type-strain Rahnella aquatilis ATCC 33071 isolated from these soils; (v) determine if polyphosphate accumulation and phytate hydrolysis can be used to promote U(VI) biomineralization in subsurface sediments; (vi) characterize the effect of uranium on phytate hydrolysis by a new microorganism isolated from uranium-contaminated sediments; (vii) utilize positron-emission tomography to label and track metabolically-active bacteria in soil columns, and (viii) study the stability of the uranium phosphate mineral product. Microarray analyses and mineral precipitation characterizations were conducted in collaboration with DOE SBR-funded investigators at LBNL. Thus, microbial phosphorus metabolism has been shown to have a contributing role to uranium immobilization in the subsurface.

  13. Elimination of natural uranium and {sup 226}Ra from contaminated waters by rhizofiltration using Helianthus annuus L

    Energy Technology Data Exchange (ETDEWEB)

    Vera Tome, F. [Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain)], E-mail: fvt@unex.es; Blanco Rodriguez, P. [Departamento de Fisica, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain); Lozano, J.C. [Laboratorio de Radiactividad Ambiental, Facultad de Ciencias, Universidad de Salamanca, 37008 Salamanca (Spain)

    2008-04-15

    The elimination of natural uranium and {sup 226}Ra from contaminated waters by rhizofiltration was tested using Helianthus annuus L. (sunflower) seedlings growing in a hydroponic medium. Different experiments were designed to determine the optimum age of the seedlings for the remediation process, and also to study the principal way in which the radionuclides are removed from the solution by the sunflower roots. In every trial a precipitate appeared which contained a major fraction of the natural uranium and {sup 226}Ra. The results indicated that the seedlings themselves induced the formation of this precipitate. When four-week-old seedlings were exposed to contaminated water, a period of only 2 days was sufficient to remove the natural uranium and {sup 226}Ra from the solution: about 50% of the natural uranium and 70% of the {sup 226}Ra were fixed in the roots, and essentially the rest was found in the precipitate, with only very small percentages fixed in the shoots and left in solution.

  14. 76 FR 63330 - Policy Regarding Submittal of Amendments for Processing of Equivalent Feed at Licensed Uranium...

    Science.gov (United States)

    2011-10-12

    ... of Amendments for Processing of Equivalent Feed at Licensed Uranium Recovery Facilities AGENCY... amendment, of equivalent feed at an NRC and Agreement State-licensed uranium recovery site. This action is... Licensing of Uranium and Thorium Recovery Facilities--Proposed New 10 CFR Part 41,'' available at...

  15. [Contrast study on natural radioactive nuclides contents of rice between Xiangshan uranium deposit area, Jiangxi and non-uranium depsoit area].

    Science.gov (United States)

    Liu, Ping-Hui; Ye, Chang-Sheng; Xie, Shu-Rong; Rui, Yu-Kui

    2009-07-01

    The contents of natural radioactive nuclides such as uranium and thorium in paddies were analyzed and compared by means of ICP-MS. Totally 14 paddy samples were distinguished into two groups and collected from two rice planting area. One group (12 paddy samples) was collected from the Xiangshan uranium deposit area, Jiangxi province; while the other group (2 samples) collected from non-uranium deposit suburban area of Fuzhou city, Jiangxi, as comparison samples. The distance between the two sampling areas is about 80 kilometers. Before analysis, those paddy samples were continuously carbonized by two hours first, then continuously incinerated for 8 hours at the temperature of 600 degrees centigrade. The results show that the uranium contents in the paddy ash of samples gotten from Xiangshan uranium deposit area range from 0.053 to 1.482 microg x g(-1). The uranium contents of two comparison paddy samples ash are 0.059 and 0.061 microg x g(-1), respectiovely. The average uranium content of paddy ash of uranium deposit area is 0.323 microg x g(-1). Compared with the comparison samples, the uranium contents of paddy ash of uranium deposit area are considerably high, 5.30 times that of non-uranium deposit area. The thorium contents in paddy ash of the uranium deposit area, however, are relatively low and less than that of samples collected from non-uranium deposit area, which range from 0.029 to 0.311 microg x g(-1); The average level is 0.104 microg x g(-1), only about 50% of that of paddy ash sampled from non-urnaium deposit area. Moreover, there is significant linearity correlation between uranium and thorium contents of paddy sampled from Xiangshan uranium deposit area. The positive effects show that the thorium contents of paddy increase as uranium contents of paddy in uranium deposit area increase. The causes for the remarkable difference in uranium contents in paddy between urianium deposit area and non-uranium deposit area are not clear yet. The research on

  16. Determination of natural and depleted uranium in urine at the ppt level: an interlaboratory analytical exercise

    Energy Technology Data Exchange (ETDEWEB)

    D' Agostino, P.A. [Defence R and D Canada - Suffield, Medicine Hat, Alberta (Canada); Ough, E.A. [Royal Military College of Canada, Kingston, Ontario (Canada); Glover, S.E. [Los Alamos National Lab., Los Alamos, NM (United States); Vallerand, A.L.

    2002-10-15

    An analytical exercise was initiated in order to determine those analytical procedures with the capacity to measure uranium isotope ratios ({sup 238}U/{sup 235}U) in urine samples containing less that 1{mu} uranium /L urine. A host laboratory was tasked with the preparation of six sets (12 samples per set) of synthetic urine samples spiked with varying amounts of natural and depleted (0.2% {sup 235}U) uranium. The sets of samples contained total uranium in the range 25 ng U/L urine to 770 ng U/L urine, with isotope ratios ({sup 238}U/{sup 235}U) from 137.9 (natural uranium) to 215 ({approx}50% depleted uranium). Sets of samples were shipped to five testing laboratories (four Canadian and one European) for total and isotopic assay. The techniques employed in the analyses included sector field inductively coupled plasma mass spectrometry (ICP-SF-MS), quadrupole inductively coupled plasma mass spectrometry (ICP-Q-MS), thermal ionization mass spectrometry (TIMS) and neutron activation analysis (NAA). Full results were obtained from three testing labs (ICP-SF-MS, ICP-Q-MS and TIMS). Their results, plus partial results from the NAA lab, have been included in this report. Total uranium and isotope ratio results obtained from ICP-SF-MS and ICP-Q-MS were in good agreement with the host lab values. Neutron activation analysis and TIMS reported total uranium concentrations that differed from the host lab. An incomplete set of isotopic ratios was obtained from the NAA lab with some results reporting enriched uranium (%{sup 235}U > 0.7). Based on the reported results, the four analytical procedures were ranked: ICP-SF-MS (1), ICP-Q-MS (2), TIMS (3) and NAA (4). (author)

  17. Natural uranium lattice in heavy water; Reseaux uranium naturel-eau lourde

    Energy Technology Data Exchange (ETDEWEB)

    Girard, Y.; Koechlin, J.C.; Moreau, J.; Naudet, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-01

    all solid bars are considered and n an d the effective integrals are adjusted then a system of transposition of these results to more complex bars is sought. In the second step, one is compelled to improve the system in studying in greater detail each factor of the calculation of the lattice. A satisfactory interpretation of the results leads definitively to methods of calculation applicable to the most varied types of natural uranium-heavy water lattices. Attention has been given to results obtained in other countries, particularly in Canada. (author) [French] Un ensemble de mesures de Laplaciens a ete realise en regime critique dans une pile a eau lourde construite specialement a cette fin, soit sur reseaux complets, soit sur echantillons de reseaux par une methode a deux zones. L'appareillage experimental est brievement decrit: il a ete etudie pour permettre des modifications rapides du chargement. On decrit egalement sommairement les methodes de mesure: on opere soit par cartes de flux, sur des reseaux qui servent ensuite de reference soit par remplacement progressif des barres par couronnes concentriques et mesures de reactivite. Dans ce cas, on cherche a atteindre l'ecart entre le laplacien-matiere du reseau central inconnu et celui du reseau de reference. La methode a fait l'objet d'une mise au point destinee a la rendre precice. On donne les resultats des mesures de laplaciens pour tous ces types de reseaux, ce qui permet de construire un ensemble de courbes en fonction du pas. Divers effets ont ete egalement mesure: equivalent en reactivite du millimetre d'eau - anisotropie - effet de temperature, etc. On a cependant prefere, dans cette premiere campagne de mesures tout au moins, obtenir une grande variete de laplaciens plutot que des mesures fines dans des cas particuliers. C'est dans cet esprit qu'a ete conduite l'interpretation des resultats. Nombre de phenomenes tres complexes echappant encore a nos possibilites de

  18. Uranium redistribution under oxidizing conditions in Oklo natural reactor zone 2, Gabon

    Energy Technology Data Exchange (ETDEWEB)

    Isobe, H.; Ohnuki, T. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan); Murakami, T. [Ehime Univ., Matsuyama, Ehime (Japan); Gauthier-Lafaye, F. [CNRS, Strasbourg (France). Centre de Geochemie de la Surface

    1995-12-31

    This mineralogical study was completed to elucidate the relationships between uranium distribution and alteration products of the host rock of natural reactor zone clays just below the reactor core. Uraninite is preserved without any alteration in the reactor core. Uranium minerals are found to be present in the fractures in the reactor zone clays associated with iron-mineral veins, galena and Ti-bearing minerals. Uranium, for which the phases could not be identified, occurs in iron-mineral veins and the iron-mineral rim of pyrite grains in the reactor zone clays. Uranium is not associated with granular iron minerals occurring in the illite matrix of the reactor zone clays. The degree of crystallinity and uranium content of the three iron-bearing alteration products suggest that they formed under different conditions; the granular iron minerals, under alteration conditions where uranium was not mobilized while the iron-mineral veins and the iron-mineral rim of pyrite, under conditions in which uranium is mobilized after the formation of the granular iron minerals.

  19. Determining factors in the elimination of uranium and radium from groundwaters during a standard potabilization process

    Energy Technology Data Exchange (ETDEWEB)

    Baeza, A. [Departamento de Fisica, Facultad de Veterinaria, Universidad de Extremadura, Avda. de la Universidad s/n 10071 Caceres (Spain)], E-mail: ymiralle@unex.es; Salas, A. [Departamento de Fisica, Facultad de Veterinaria, Universidad de Extremadura, Avda. de la Universidad s/n 10071 Caceres (Spain); Legarda, F. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Superior de Ingenieros, Universidad de Pais Vasco, Alameda de Urquijo s/n 48013 Bilbao (Spain)

    2008-11-15

    We studied the physico-chemical and radioactive characteristics of four waters of subsurface origin. They were chosen for having the highest natural radioactivity levels of waters for human consumption in the Autonomous Community of Extremadura, Spain Their activity levels for alpha emitting radionuclides are between 120 and 19 300 mBq L{sup -1}, all exceeding the 100 mBq L{sup -1} threshold established in the European Union above which radioactive isotopes that are present in water should be investigated to determine which corrective action, if any, is needed. These waters were used to compare the efficiency in eliminating their uranium and radium content of two potabilization processes - one the standard chlorination-only process used by their respective municipalities, and the other a procedure consisting of coagulation, flocculation, settling, filtration, and chlorination stages, specifically designed to maximize the elimination of their natural radioactive content. The results showed the uranium and radium elimination efficiencies to depend strongly on the water's hydrogencarbonate, calcium, and magnesium ion concentrations. In particular, with increasing concentrations of any of these ions, the uranium elimination efficiency fell from 90% to 60% at its optimal working pH, pH = 6, while the radium elimination efficiency rose from 50% to 90% at its optimal working pH, pH = 10.

  20. Studies of Uranium Recovery from Tunisian Wet Process Phosphoric Acid

    OpenAIRE

    2013-01-01

    The growing worldwide energy demand associated with several inter related complex environmental as well as economical issues are driving the increase of the share of uranium in energy mix. Subsequently, over the last few years, the interest for uranium extraction and recovery from unconventional resources has gained considerable importance. Phosphate rock has been the most suitable alternative source for the uranium recovery because of its uranium content. Solvent extraction has been found to...

  1. Natural uranium lattice in heavy water; Reseaux uranium naturel-eau lourde

    Energy Technology Data Exchange (ETDEWEB)

    Girard, Y.; Koechlin, J.C.; Moreau, J.; Naudet, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-01

    all solid bars are considered and n an d the effective integrals are adjusted then a system of transposition of these results to more complex bars is sought. In the second step, one is compelled to improve the system in studying in greater detail each factor of the calculation of the lattice. A satisfactory interpretation of the results leads definitively to methods of calculation applicable to the most varied types of natural uranium-heavy water lattices. Attention has been given to results obtained in other countries, particularly in Canada. (author) [French] Un ensemble de mesures de Laplaciens a ete realise en regime critique dans une pile a eau lourde construite specialement a cette fin, soit sur reseaux complets, soit sur echantillons de reseaux par une methode a deux zones. L'appareillage experimental est brievement decrit: il a ete etudie pour permettre des modifications rapides du chargement. On decrit egalement sommairement les methodes de mesure: on opere soit par cartes de flux, sur des reseaux qui servent ensuite de reference soit par remplacement progressif des barres par couronnes concentriques et mesures de reactivite. Dans ce cas, on cherche a atteindre l'ecart entre le laplacien-matiere du reseau central inconnu et celui du reseau de reference. La methode a fait l'objet d'une mise au point destinee a la rendre precice. On donne les resultats des mesures de laplaciens pour tous ces types de reseaux, ce qui permet de construire un ensemble de courbes en fonction du pas. Divers effets ont ete egalement mesure: equivalent en reactivite du millimetre d'eau - anisotropie - effet de temperature, etc. On a cependant prefere, dans cette premiere campagne de mesures tout au moins, obtenir une grande variete de laplaciens plutot que des mesures fines dans des cas particuliers. C'est dans cet esprit qu'a ete conduite l'interpretation des resultats. Nombre de phenomenes tres complexes echappant encore a nos possibilites de

  2. Linearity assumption in soil-to-plant transfer factors of natural uranium and radium in Helianthus annuus L

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, P. Blanco [Departamento de Fisica, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain); Tome, F. Vera [Departamento de Fisica, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain)]. E-mail: fvt@unex.es; Fernandez, M. Perez [Area de Ecologia, Departamento de Fisica, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain); Lozano, J.C. [Laboratorio de Radiactividad Ambiental, Facultad de Ciencias, Universidad de Salamanca, 37008 Salamanca (Spain)

    2006-05-15

    The linearity assumption of the validation of soil-to-plant transfer factors of natural uranium and {sup 226}Ra was tested using Helianthus annuus L. (sunflower) grown in a hydroponic medium. Transfer of natural uranium and {sup 226}Ra was tested in both the aerial fraction of plants and in the overall seedlings (roots and shoots). The results show that the linearity assumption can be considered valid in the hydroponic growth of sunflowers for the radionuclides studied. The ability of sunflowers to translocate uranium and {sup 226}Ra was also investigated, as well as the feasibility of using sunflower plants to remove uranium and radium from contaminated water, and by extension, their potential for phytoextraction. In this sense, the removal percentages obtained for natural uranium and {sup 226}Ra were 24% and 42%, respectively. Practically all the uranium is accumulated in the roots. However, 86% of the {sup 226}Ra activity concentration in roots was translocated to the aerial part.

  3. The Palmottu natural analogue project. The behaviour of natural radionuclides in and around uranium deposits. Summary report 1992-1994

    Energy Technology Data Exchange (ETDEWEB)

    Blomqvist, R.; Ruskeeniemi, T.; Ahonen, L. [Geological Survey of Finland, Espoo (Finland); Suksi, J. [Helsinki Univ. (Finland). Lab. of Radiochemistry; Niini, H. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Engineering Geology and Geophysics; Vuorinen, U. [VTT Chemical Technology, Espoo (Finland); Jakobsson, K. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1995-06-01

    The Palmottu U-Th mineralization at Nummi-Pusula, southwestern Finland, has been studied as a natural analogue to deep disposal of radioactive wastes since 1988. The report gives a summary of the results of investigations carried out during the years 1992-1994. The Palmottu Analogue Project aims at a more profound understanding of radionuclide transport processes in fractured crystalline bedrock. The essential factors controlling transport are groundwater flow and interaction between water and rock. Accordingly, the study includes structural interpretations based in part on geophysical measurements, hydrological studies including hydraulic downhole measurements, flow modelling, hydrogeochemical characterization of groundwater, uranium chemistry and colloid chemistry, mineralogical studies, geochemical interpretation and modelling, including paleohydrogeological aspects, and studies of radionuclide mobilization and migration processes including numerical simulations. The project has produced a large amount of data related to natural analogue aspects. The data obtained have already been utilized in developing logical conceptual ideas of the time frames and processes operating in the bedrock of the site. (61 refs., 24 figs., 8 tabs.).

  4. Efficient introduction of natural uranium and thorium into nuclear energy system

    Energy Technology Data Exchange (ETDEWEB)

    Blandinskiy, Victor [National Research Centre ' Kurchatov Institute' , Moscow (Russian Federation)

    2016-09-15

    This article describes differences between two approaches of understanding the main goal of nuclear energy system: effective plutonium consumption versus effective natural uranium and thorium consumption. Several options of sodium cooled fast reactor are considered to provide increased breeding and thorium involving into nuclear energy system.

  5. EXPOSURE LEVELS FOR PERSONNEL OF NON-URANIUM UNDERGROUND ENTERPRISES FROM NATURAL IRRADIATION SOURCES

    Directory of Open Access Journals (Sweden)

    N. A. Koroljova

    2008-01-01

    Full Text Available The article contains the analysis of the results of radiation survey at more than 100 non-uranium mining enterprises fulfilled by the Institute over the last 20 years. The article considers radiation situation formation appropriateness, demonstrates the evaluation of effective exposure doses of mining enterprises personnel from natural irradiation sources in working conditions, the dose structure is given.

  6. High resolution remote sensing image processing technology and its application to uranium geology

    Science.gov (United States)

    Zhang, Jie-lin

    2008-12-01

    Hyperspectral and high spatial resolution remote sensing technology take important role in uranium geological application, data mining and knowledge discovery methods are key to character spectral and spatial information of uranium mineralization factors. Based on curvelet transform algorithm, this paper developed the image fusion technology of hyperspectral (Hyperion) and high spatial data (SPOT5), and results demonstrated that fusion image had advantage in denoising, enhancing and information identification. Used discrete wavelet transform, the spectral parameters of uranium mineralization factors were acquired, the spectral identification pedigrees of typical quadrivalence and hexavalence uranium minerals were established. Furthermore, utilizing hyperspectral remote sensing observation technology, this paper developed hyperspectral logging of drill cores and trench, it can quickly processed lots of geological and spectral information, and the relationship between radioactive intensity and abnormal spectral characteristics of Fe3+ was established. All those provided remote sensing technical bases to uranium geology, and the better results have been achieved in Taoshan uranium deposits in south China.

  7. AMS of natural 236U and 239Pu produced in uranium ores

    Science.gov (United States)

    Wilcken, K. M.; Barrows, T. T.; Fifield, L. K.; Tims, S. G.; Steier, P.

    2007-06-01

    The rare isotopes 236U and 239Pu are produced naturally by neutron capture in uranium ores. Here we measure 236U and 239Pu by accelerator mass spectrometry (AMS) in the same ore samples for the first time. To ensure efficient extraction of both elements and isotopic equilibrium between the 239Pu in the ore and a 242Pu spike, we developed a new sample preparation protocol. AMS has clear advantages over previous methods because it achieves better discrimination against molecular interferences with higher sensitivity and shorter counting times. Measurements of 236U and 239Pu hold considerable promise as proxy indicators of neutron flux and uranium concentration.

  8. Method of quantitatively separating uranium from specimens of natural water by sorption on silica

    Energy Technology Data Exchange (ETDEWEB)

    Putral, A.; Schwochau, K.

    1981-08-11

    A method of quantitatively separating uranium from specimens of natural water, especially sea water or from solutions which as to their composition are comparable to such specimens, while silica gel is provided for adsorbing the uranium. The liquid of the specimens or solution is conveyed over granular silica gel having an average grain diameter not exceeding 0.5 mm. The through-flow speed is so selected that the contact time period for the liquid with the silica gel amounts to at least 50 seconds, whereupon the uranium adsorbed on the silica gel is separated therefrom by elutriation with at least 0.1 normal oxidizing mineral acid. The volume of the elutriate utilized, should amount to at least twice the volume of the silica gel, and this proportion of the elutriate should, if possible, not be exceeded.

  9. Uranium Biomineralization by Natural Microbial Phosphatase Activities in the Subsurface

    Science.gov (United States)

    Martinez, R.; Wu, C. H.; Beazley, M. J.; Andersen, G. L.; Hazen, T. C.; Taillefert, M.; Sobecky, P. A.

    2011-12-01

    Soils and groundwater contaminated with heavy metals and radionuclides remain a legacy of Cold War nuclear weapons development. Due to the scale of environmental contamination, in situ sequestration of heavy metals and radionuclides remain the most cost-effective strategy for remediation. We are currently investigating a remediation approach that utilizes periplasmic and extracellular microbial phosphatase activity of soil bacteria capable promoting in situ uranium phosphate sequestration. Our studies focus on the contaminated soils from the DOE Field Research Center (ORFRC) in Oak Ridge, TN. We have previously demonstrated that ORFRC strains with phosphatase-positive phenotypes were capable of promoting the precpitation of >95% U(VI) as a low solubility phosphate mineral during growth on glycerol phosphate as a sole carbon and phosphorus source. Here we present culture-independent soil slurry studies aimed at understanding microbial community dynamics resulting from exogenous organophosphate additions. Soil slurries containing glycerol-2-phosphate (G2P) or glycerol-3-phosphate (G3P) and nitrate as the sole C, P and N sources were incubated under oxic growth conditions at pH 5.5 or pH 6.8. Following treatments, total DNA was extracted and prokaryotic diversity was assessed using high-density 16S oligonucleotide microarray (PhyloChip) analysis. Treatments at pH 5.5 and pH 6.8 amended with G2P required 36 days to accumulate 4.8mM and 2.2 mM phosphate, respectively. In contrast, treatments at pH 5.5 and pH 6.8 amended with G3P accumulated 8.9 mM and 8.7 mM phosphate, respectively, after 20 days. A total of 2120 unique taxa representing 46 phyla, 66 classes, 110 orders, and 186 families were detected among all treatment conditions. The phyla that significantly (P<0.05) increased in abundance relative to incubations lacking organophosphate amendments included: Crenarchaeota, Euryarchaeota, Bacteroidetes, and Proteobacteria. Members from the classes Bacteroidetes

  10. Genetic Relationship between Natural Gas Dispersal Zone and Uranium Accumulation in the Northern Ordos Basin, China

    Institute of Scientific and Technical Information of China (English)

    GAN Huajun; XIAO Xianming; LU Yongchao; JIN Yongbin; TIAN Hui; LIU Dehan

    2007-01-01

    The Ordos Basin is well-known for the coexistence of oil, natural gas, coal and uranium. However, there has been little research to discuss the genetic relationship between them. In this paper, a case study of the Zaohuohao area in Dongsheng, Inner Mongolia, China, is conducted to investigate the genetic relationship between the natural gas and the uranium accumulation. Fluid inclusion data from the uranium-bearing sandstone samples indicate that the fluid inclusions formed in a gas-water transition zone. Using the homogeneous temperatures of aqueous inclusions coeval with hydrocarbonbearing inclusions, combined with the buried history and paleo-temperature data, the gas-water transition zone reached the area at about 110 Ma. On the basis of this, the contents of Uranium (U)and Total Organic Carbon (TOC) of the samples were analyzed, and there was no obvious relation between them. With regard to the available data from both publications and this study, it is found that the U mineralization has a spatiotemporal accordance with the gas-water dispersal zone. Thus, it is believed that the natural gas in the gas-water zone is an effective reducer to the U-bearing ground water abundant in oxygen, which is the main factor to U accumulation. This result can be used as the reference to the U mines predicting and prospecting.

  11. The determination of minor isotope abundances in naturally occurring uranium materials. The tracing power of isotopic signatures for uranium

    Energy Technology Data Exchange (ETDEWEB)

    Ovaskainen, R

    1999-11-01

    The mass spectrometric determination of minor abundant isotopes, {sup 234}U and {sup 236}U in naturally occurring uranium materials requires instruments of high abundance sensitivity and the use of highly sensitive detection systems. In this study the thermal ionisation mass spectrometer Finnigan MAT 262RPQ was used. It was equipped with 6 Faraday cups and a Secondary Electron Multiplier (SEM), which was operated in pulse counting mode for the detection of extremely low ion currents. The dynamic measurement range was increased considerably combining these two different detectors. The instrument calibration was performed carefully. The linearity of each detector, the deadtime of the ion counting detector, the detector normalisation factor, the baseline of each detector and the mass discrimination in the ion source were checked and optimised. A measurement technique based on the combination of a Gas Source Mass Spectrometry (GSMS) and a Thermal Ionisation Mass Spectrometry (TIMS) was developed for the accurate determination of isotopic composition in naturally occurring uranium materials. Because the expected ratio of n({sup 234}U)/n({sup 238}U) exceeded the dynamic measurement range of the Faraday detectors of the TIMS instrument, an experimental design using a combination of two detectors was developed. The n({sup 234}U)/n({sup 235}U) and n({sup 236}U)/n({sup 235}U) ratios were determined using ion counting in combination with the decelerating device. The n({sup 235}U)/n({sup 238}U) ratio was determined by the Faraday detector. This experimental design allowed the detector cross calibration to be circumvented. Precisions of less than 1 percent for the n({sup 234}U)/n({sup 235}U) ratios and 5-25 percent for the n({sup 236}U)/n({sup 235}U) ratios were achieved. The purpose of the study was to establish a register of isotopic signatures for natural uranium materials. The amount ratio, and isotopic composition of 18 ore concentrates, collected by the International

  12. 78 FR 21352 - Update on Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2013-04-10

    ... on Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites AGENCY... reimbursement for cleanup work performed by licensees at eligible uranium and thorium processing sites in... licensees of eligible uranium and thorium processing sites. If licensees submit claims in FY 2013,...

  13. Processing of Sierra Albarrana uranium ores; Tratamiento de los minerales de uranio de Sierra Albarrana

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez Jodra, L.; Perez Luina, A.; Perarnau, M.

    1960-07-01

    Uranium recovery by hydrometallurgy from brannerite, found in Hornachuelos (Cordoba) is described. It has been studied the acid and alkaline leaching and salt roasting, proving as more satisfactory the acid leaching. Besides the uranium solubilization by acid leaching, is described the further process to obtain pure uranyl nitrate. (Author)

  14. Uranium Metal to Oxide Conversion by Air Oxidation –Process Development

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, A

    2001-12-31

    Published technical information for the process of metal-to-oxide conversion of uranium components has been reviewed and summarized for the purpose of supporting critical decisions for new processes and facilities for the Y-12 National Security Complex. The science of uranium oxidation under low, intermediate, and high temperature conditions is reviewed. A process and system concept is outlined and process parameters identified for uranium oxide production rates. Recommendations for additional investigations to support a conceptual design of a new facility are outlined.

  15. Assessment of contamination of the Issyk-Kul' valley natural waters with uranium mine wastes

    Energy Technology Data Exchange (ETDEWEB)

    Palesski, S.V.; Nikolaeva, I.V.; Saprykin, A.I.; Gavshin, V.M. [The United Institute of Geology, Geophysics and Mineralogy SB RAS, Novosibirsk (Russian Federation)

    2003-05-01

    The Lake Issyk-Kul' of the central Tyan-Shan is characterized by increased natural uranium content. Uranium-carbon deposit situated on the southern bank of the Lake can be the reason of chemical and radioactive contamination of this unique basin by exploitation wastes. In order to estimate possible danger, a project 'Assessment and prognosis of environmental changes in Lake Issyk-Kul' (Kyrgyzstan)' was developed and supported by the Program of the European Commission 'Copernicus-2' (2001-2003). According to this project the water assays were sampled from different depths near the banks of the Lake and from low-debit sources draining the dumping grounds of the uranium-carbon deposit. Elemental and isotopic examinations of these water samples were performed using an ELEMENT HR-ICP-MS (Finnigan Mat). The results obtained are the evidence that the ecological status of the Lake Issyk-Kul'is not damaged at present. Wastewaters from the uranium-carbon mine do not make decisive contribution into the natural radioactive background. (authors)

  16. Metabolomics identifies a biological response to chronic low-dose natural uranium contamination in urine samples.

    Science.gov (United States)

    Grison, Stéphane; Favé, Gaëlle; Maillot, Matthieu; Manens, Line; Delissen, Olivia; Blanchardon, Eric; Banzet, Nathalie; Defoort, Catherine; Bott, Romain; Dublineau, Isabelle; Aigueperse, Jocelyne; Gourmelon, Patrick; Martin, Jean-Charles; Souidi, Maâmar

    2013-01-01

    Because uranium is a natural element present in the earth's crust, the population may be chronically exposed to low doses of it through drinking water. Additionally, the military and civil uses of uranium can also lead to environmental dispersion that can result in high or low doses of acute or chronic exposure. Recent experimental data suggest this might lead to relatively innocuous biological reactions. The aim of this study was to assess the biological changes in rats caused by ingestion of natural uranium in drinking water with a mean daily intake of 2.7 mg/kg for 9 months and to identify potential biomarkers related to such a contamination. Subsequently, we observed no pathology and standard clinical tests were unable to distinguish between treated and untreated animals. Conversely, LC-MS metabolomics identified urine as an appropriate biofluid for discriminating the experimental groups. Of the 1,376 features detected in urine, the most discriminant were metabolites involved in tryptophan, nicotinate, and nicotinamide metabolic pathways. In particular, N-methylnicotinamide, which was found at a level seven times higher in untreated than in contaminated rats, had the greatest discriminating power. These novel results establish a proof of principle for using metabolomics to address chronic low-dose uranium contamination. They open interesting perspectives for understanding the underlying biological mechanisms and designing a diagnostic test of exposure.

  17. Hypertension and hematologic parameters in a community near a uranium processing facility

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Sara E., E-mail: swagner@uga.edu [College of Public Health, Department of Epidemiology and Biostatistics, Paul D. Coverdell Center for Biomedical and Health Sciences, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602-7396 (United States); Burch, James B. [Arnold School of Public Health, Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC (United States); South Carolina Statewide Cancer Prevention and Control Program, Columbia, SC (United States); WJB Dorn Veteran' s Affairs Medical Center, Columbia, SC (United States); Bottai, Matteo [Arnold School of Public Health, Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC (United States); Pinney, Susan M. [College of Medicine, Department of Environmental Health, University of Cincinnati, Cincinnati, OH (United States); Puett, Robin [Arnold School of Public Health, Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC (United States); South Carolina Statewide Cancer Prevention and Control Program, Columbia, SC (United States); Arnold School of Public Health, Department of Environmental Health Sciences, University of South Carolina, Columbia, SC (United States); Porter, Dwayne [Arnold School of Public Health, Department of Environmental Health Sciences, University of South Carolina, Columbia, SC (United States); Vena, John E. [College of Public Health, Department of Epidemiology and Biostatistics, Paul D. Coverdell Center for Biomedical and Health Sciences, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602-7396 (United States); Hebert, James R. [Arnold School of Public Health, Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC (United States); South Carolina Statewide Cancer Prevention and Control Program, Columbia, SC (United States)

    2010-11-15

    Background: Environmental uranium exposure originating as a byproduct of uranium processing can impact human health. The Fernald Feed Materials Production Center functioned as a uranium processing facility from 1951 to 1989, and potential health effects among residents living near this plant were investigated via the Fernald Medical Monitoring Program (FMMP). Methods: Data from 8216 adult FMMP participants were used to test the hypothesis that elevated uranium exposure was associated with indicators of hypertension or changes in hematologic parameters at entry into the program. A cumulative uranium exposure estimate, developed by FMMP investigators, was used to classify exposure. Systolic and diastolic blood pressure and physician diagnoses were used to assess hypertension; and red blood cells, platelets, and white blood cell differential counts were used to characterize hematology. The relationship between uranium exposure and hypertension or hematologic parameters was evaluated using generalized linear models and quantile regression for continuous outcomes, and logistic regression or ordinal logistic regression for categorical outcomes, after adjustment for potential confounding factors. Results: Of 8216 adult FMMP participants 4187 (51%) had low cumulative uranium exposure, 1273 (15%) had moderate exposure, and 2756 (34%) were in the high (>0.50 Sievert) cumulative lifetime uranium exposure category. Participants with elevated uranium exposure had decreased white blood cell and lymphocyte counts and increased eosinophil counts. Female participants with higher uranium exposures had elevated systolic blood pressure compared to women with lower exposures. However, no exposure-related changes were observed in diastolic blood pressure or hypertension diagnoses among female or male participants. Conclusions: Results from this investigation suggest that residents in the vicinity of the Fernald plant with elevated exposure to uranium primarily via inhalation exhibited

  18. Assessment of natural radioactivity in aquifer medium bearing uranium ores in Koprubasi, Turkey

    Science.gov (United States)

    Simsek, Celalettin

    2008-10-01

    Koprubasi, located within Manisa Province near the Izmir, is the biggest uranium mine where uranium ores originate from Neogene aged altered sandstone and conglomerate layers. The main objective of this study is to determine the radiation hazard associated with radioactivity levels of uranium ores, and the rocks and sediments around Koprubasi. In this regard, measured activity levels of 226Ra, 232Th and 40K were compared with world averages. The average activity levels of 226 Ra, 232Th and 40K were measured to be 5369.75, 124.78 and 10.0 Bq/kg in uranium ores, 24.32, 52.94 and 623.38 Bq/kg in gneiss, 46.24, 45.13 and 762.26 Bq/kg in sandstone and conglomerate, 73.11, 43.15 and 810.65 Bq/kg in sediments, respectively. All samples have high 226Ra and 40K levels according to world average level. As these sediments are used as construction materials and in agricultural activities within the study area, the radiation hazard are calculated by using dose rate (D), annual effective dose rate (He), radium equivalent activity (Raeq) and radiation hazard index (Iyr). All the samples have Raeq levels that are lower than the world average limit of 370 Bq/kg. On the other hand, D, He and Iyr values are higher than world average values. These results indicate that the uranium ores in the Koprubasi is the most important contributor to the natural radiation level. The radioactivity levels of sediments and rocks make them unsuitable for use as agricultural soil and as construction materials. Moreover, it is determined that shallow groundwater in sediments and deep groundwater in conglomerate rocks and also surface water sources in the Koprubasi have high 226Ra content. According to environmental radioactive baseline, some environmental protection study must be taken in Koprubasi uranium site and the environment.

  19. Natural gas conversion process

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    The experimental apparatus was dismantled and transferred to a laboratory space provided by Lawrence Berkeley Laboratory (LBL) which is already equipped with a high-ventilation fume hood. This will enable us to make tests at higher gas flow rates in a safe environment. Three papers presented at the ACS meeting in San Francisco (Symposium on Natural Gas Upgrading II) April 5--10, 1992 show that the goal of direct catalytic conversion of Methane into heavier Hydrocarbons in a reducing atmosphere is actively pursued in three other different laboratories. There are similarities in their general concept with our own approach, but the temperature range of the experiments reported in these recent papers is much lower and this leads to uneconomic conversion rates. This illustrates the advantages of Methane activation by a Hydrogen plasma to reach commercial conversion rates. A preliminary process flow diagram was established for the Integrated Process, which was outlined in the previous Quarterly Report. The flow diagram also includes all the required auxiliary facilities for product separation and recycle of the unconverted feed as well as for the preparation and compression of the Syngas by-product.

  20. Spectroscopic Evidence of Uranium Immobilization in Acidic Wetlands by Natural Organic Matter and Plant Roots

    Science.gov (United States)

    Biogeochemistry of uranium in wetlands plays important roles in U immobilization in storage ponds of U mining and processing facilities but has not been well understood. The objective of this work was to study molecular mechanisms responsible for high U retention by Savannah Ri...

  1. EPR pilot study on the population of Stepnogorsk city living in the vicinity of a uranium processing plant

    Energy Technology Data Exchange (ETDEWEB)

    Zhumadilov, Kassym; Akilbekov, Abdirash; Morzabayev, Aidar [L.N. Gumilyov Eurasian National University, Astana (Kazakhstan); Ivannikov, Alexander; Stepanenko, Valeriy [Medical Radiological Research Center, Obninsk (Russian Federation); Abralina, Sholpan; Sadvokasova, Lyazzat; Rakhypbekov, Tolebay [Semey State Medical University, Semey (Kazakhstan); Hoshi, Masaharu [Hiroshima University, Research Institute for Radiation Biology and Medicine, Hiroshima (Japan)

    2015-03-15

    The aim of this pilot study was to evaluate possible doses in teeth received by workers of a uranium processing plant, in excess to the natural background dose. For this, the electron paramagnetic resonance dosimetry method was applied. Absorbed doses in teeth from the workers were compared with those measured in teeth from the Stepnogorsk city population and a control pool population from Astana city. The measured tooth samples were extracted according to medical indications. In total, 32 tooth enamel samples were analyzed, 5 from Astana city, Kazakhstan (control population), 21 from the residents of Stepnogorsk city (180 km from Astana city), and 6 from the workers of a uranium processing plant. The estimated doses in tooth enamel from the uranium processing plant workers were not significantly different to those measured in enamel from the control population. In teeth from the workers, the maximum dose in excess to background dose was 33 mGy. In two teeth from residents of Stepnogorsk city, however, somewhat larger doses were measured. The results of this pilot study encourage further investigations in an effort to receiving a final conclusion on the exposure situation of the uranium processing plant workers and the residents of Stepnogorsk city. (orig.)

  2. PROCESS FOR THE RECOVERY OF URANIUM FROM PHOSPHATIC ORE

    Science.gov (United States)

    Long, R.L.

    1959-04-14

    A proccss is described for the recovery of uranium from phosphatic products derived from phosphatic ores. It has been discovered that certain alkyl phosphatic, derivatives can be employed in a direct solvent extraction operation to recover uranium from solid products, such as superphosphates, without first dissolving such solids. The organic extractants found suitable include alkyl derivatives of phosphoric, pyrophosphoric, phosof the derivative contains from 4 to 7 carbon atoms. A diluent such as kerosene is also used.

  3. Natural uranium and thorium isotopes in sediment cores off Malaysian ports

    Science.gov (United States)

    Yusoff, Abdul Hafidz; Sabuti, Asnor Azrin; Mohamed, Che Abd Rahim

    2015-06-01

    Sediment cores collected from three Malaysian marine ports, namely, Kota Kinabalu, Labuan and Klang were analyzed to determine the radioactivities of 234U, 238U, 230Th, 232Th and total organic carbon (TOC) content. The objectives of this study were to determine the factors that control the activity of uranium isotopes and identify the possible origin of uranium and thorium in these areas. The activities of 234U and 238U show high positive correlation with TOC at the middle of sediment core from Kota Kinabalu port. This result suggests that activity of uranium at Kota Kinabalu port was influenced by organic carbon. The 234U/238U value at the upper layer of Kota Kinabalu port was ≥1.14 while the ratio value at Labuan and Klang port was ≤ 1.14. These results suggest a reduction process occurred at Kota Kinabalu port where mobile U(VI) was converted to immobile U(IV) by organic carbon. Therefore, it can be concluded that the major input of uranium at Kota Kinabalu port is by sorptive uptake of authigenic uranium from the water column whereas the major inputs of uranium to Labuan and Klang port are of detrital origin. The ratio of 230Th/232Th was used to estimate the origin of thorium. Low ratio value (lt; 1.5) at Labuan and Klang ports support the suggestion that thorium from both areas were come from detrital input while the high ratio (> 1.5) of 230Th/232Th at Kota Kinabalu port suggest the anthropogenic input of 230Th to this area. The source of 230Th is probably from phosphate fertilizers used in the oil-palm cultivation in Kota Kinabalu that is adjacent to the Kota Kinabalu port.

  4. Natural radioactivity, dose assessment and uranium uptake by agricultural crops at Khan Al-Zabeeb, Jordan

    Energy Technology Data Exchange (ETDEWEB)

    Al-Kharouf, Samer J. [Royal Scientific Society, Amman 11941 (Jordan); Al-Hamarneh, Ibrahim F. [Prince Abdullah Bin Ghazi Faculty of Science and IT, Al-Balqa Applied University (BAU), Salt 19117 (Jordan)], E-mail: hamarnehibrahim@yahoo.com; Dababneh, Munir [Prince Abdullah Bin Ghazi Faculty of Science and IT, Al-Balqa Applied University (BAU), Salt 19117 (Jordan)

    2008-07-15

    Khan Al-Zabeeb, an irrigated cultivated area lies above a superficial uranium deposits, is regularly used to produce vegetables and fruits consumed by the public. Both soil and plant samples collected from the study area were investigated for their natural radioactivity to determine the uranium uptake by crops and hence to estimate the effective dose equivalent to human consumption. Concentrations of {sup 238}U, {sup 235}U, {sup 232}Th, {sup 226}Ra, {sup 222}Rn, {sup 137}Cs and {sup 40}K in nine soil profiles were measured by gamma-ray spectrometry whereas watermelon and zucchini crops were analyzed for their uranium content by means of alpha spectrometry after radiochemical separation. Correlations between measured radionuclides were made and their activity ratios were determined to evaluate their geochemical behavior in the soil profiles. Calculated soil-plant transfer factors indicate that the green parts (leaves, stems and roots) of the studied crops tend to accumulate uranium about two orders of magnitude higher than the fruits. The maximum dose from ingestion of 1 kg of watermelon pulp was estimated to be 3.1 and 4.7 nSv y{sup -1} for {sup 238}U and {sup 234}U, respectively. Estimations of the annual effective dose equivalent due to external exposure showed extremely low values. Radium equivalent activity and external hazard index were seen to exceed the permissible limits of 370 Bq kg{sup -1} and 1, respectively.

  5. The Chemistry and Toxicology of Depleted Uranium

    Directory of Open Access Journals (Sweden)

    Sidney A. Katz

    2014-03-01

    Full Text Available Natural uranium is comprised of three radioactive isotopes: 238U, 235U, and 234U. Depleted uranium (DU is a byproduct of the processes for the enrichment of the naturally occurring 235U isotope. The world wide stock pile contains some 1½ million tons of depleted uranium. Some of it has been used to dilute weapons grade uranium (~90% 235U down to reactor grade uranium (~5% 235U, and some of it has been used for heavy tank armor and for the fabrication of armor-piercing bullets and missiles. Such weapons were used by the military in the Persian Gulf, the Balkans and elsewhere. The testing of depleted uranium weapons and their use in combat has resulted in environmental contamination and human exposure. Although the chemical and the toxicological behaviors of depleted uranium are essentially the same as those of natural uranium, the respective chemical forms and isotopic compositions in which they usually occur are different. The chemical and radiological toxicity of depleted uranium can injure biological systems. Normal functioning of the kidney, liver, lung, and heart can be adversely affected by depleted uranium intoxication. The focus of this review is on the chemical and toxicological properties of depleted and natural uranium and some of the possible consequences from long term, low dose exposure to depleted uranium in the environment.

  6. Morphology Characterization of Uranium Particles From Laser Ablated Uranium Materials

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In the study, metallic uranium and uranium dioxide material were ablated by laser beam in order to simulate the process of forming the uranium particles in pyrochemical process. The morphology characteristic of uranium particles and the surface of

  7. Alpha spectrometric characterization of process-related particle size distributions from active particle sampling at the Los Alamos National Laboratory uranium foundry

    Energy Technology Data Exchange (ETDEWEB)

    Plionis, Alexander A [Los Alamos National Laboratory; Peterson, Dominic S [Los Alamos National Laboratory; Tandon, Lav [Los Alamos National Laboratory; Lamont, Stephen P [Los Alamos National Laboratory

    2009-01-01

    Uranium particles within the respirable size range pose a significant hazard to the health and safety of workers. Significant differences in the deposition and incorporation patterns of aerosols within the respirable range can be identified and integrated into sophisticated health physics models. Data characterizing the uranium particle size distribution resulting from specific foundry-related processes are needed. Using personal air sampling cascade impactors, particles collected from several foundry processes were sorted by activity median aerodynamic diameter onto various Marple substrates. After an initial gravimetric assessment of each impactor stage, the substrates were analyzed by alpha spectrometry to determine the uranium content of each stage. Alpha spectrometry provides rapid nondestructive isotopic data that can distinguish process uranium from natural sources and the degree of uranium contribution to the total accumulated particle load. In addition, the particle size bins utilized by the impactors provide adequate resolution to determine if a process particle size distribution is: lognormal, bimodal, or trimodal. Data on process uranium particle size values and distributions facilitate the development of more sophisticated and accurate models for internal dosimetry, resulting in an improved understanding of foundry worker health and safety.

  8. An improvement in APOR process I-uranium/plutonium separation process

    Institute of Scientific and Technical Information of China (English)

    肖松涛; 李丽; 叶国安; 罗方祥; 刘协春; 杨贺; 兰天

    2015-01-01

    The reduction stripping behavior of Pu(IV) from 30%TBP/OK with hydroxysemicarbazide (HSC) was inves-tigated, and the separation efficiency of HSC and DMHAN-MMH for U/Pu partitioning in Purex process was compared. The results show that HSC can effectively realize the separation of Pu from U;using mixer-settlers to simulate U/Pu separation in 1B bank of PUREX, from 16-stage counter current extraction experiment (in which 6 stages for supplemental extraction, 10 stages for stripping) with flow rate ratio (1BF:1BX:1BS)=4:1:1 in 1B contactor, good result was achieved that the yields are both more than 99.99%for uranium and Pu, the separation factor of plutonium from uranium (SFPu/U) is 2.8 × 104, and separation factor of uranium from plu-tonium (SFU/Pu) is 5.9 × 104. As a stripping reductant, HSC can effectively achieve the separation of Pu from U and the separation effect is nearly the same with DMHAN-MMH, which contributed to replace enough the latter with HSC in the U/Pu separation in Advanced Purex Process Based on Organic Reagent (APOR) process.

  9. Uranium conversion; Conversion de l`uranium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    This booklet is a presentation of the activities of the Comurhex company, created in 1971 and which became a 100% Cogema`s daughter company in 1992. The Comurhex company is in charge of the conversion of natural uranium into gaseous uranium hexafluoride (UF{sub 6}). The two steps of the conversion operation are performed in the Malvesi and Pierrelatte (France) industrial sites and represent 31% (14000 t/year) of the uranium conversion capacity of western countries. The refining and UF{sub 4} production (Malvesi) and the UF{sub 6} fabrication (Pierrelatte) processes are described. Comurhex is also one of the few companies in the world which produces UF{sub 6} from the uranium of spent fuels. (J.S.)

  10. Selected bibliography for the extraction of uranium from seawater: chemical process and plant design feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Binney, S.E.; Polkinghorne, S.T.; Jante, R.R.; Rodman, M.R.; Chen, A.C.T.; Gordon, L.I.

    1979-02-01

    A selected annotated bibliography of 521 references was prepared as a part of a feasibility study of the extraction of uranium from seawater. For the most part, these references are related to the chemical processes whereby the uranium is removed from the seawater. A companion docment contains a similar bibliography of 471 references related to oceanographic and uranium extraction plant siting considerations, although some of the references are in common. The bibliography was prepared by computer retrieval from Chemical Abstracts, Nuclear Science Abstracts, Energy Data Base, NTIS, and Oceanic Abstracts. References are listed by author, country of author, and selected keywords.

  11. AMS of natural {sup 236}U and {sup 239}Pu produced in uranium ores

    Energy Technology Data Exchange (ETDEWEB)

    Wilcken, K.M. [Department of Nuclear Physics, RSPhysSE, Australian National University, Canberra, ACT 0200 (Australia)]. E-mail: k.wilcken@suerc.gla.ac.uk; Barrows, T.T. [Department of Nuclear Physics, RSPhysSE, Australian National University, Canberra, ACT 0200 (Australia); Fifield, L.K. [Department of Nuclear Physics, RSPhysSE, Australian National University, Canberra, ACT 0200 (Australia); Tims, S.G. [Department of Nuclear Physics, RSPhysSE, Australian National University, Canberra, ACT 0200 (Australia); Steier, P. [VERA Laboratory, Institute for Isotopic Research and Nuclear Physics, University of Vienna, Waehringer Strasse 17, A-1090 Vienna (Austria)

    2007-06-15

    The rare isotopes {sup 236}U and {sup 239}Pu are produced naturally by neutron capture in uranium ores. Here we measure {sup 236}U and {sup 239}Pu by accelerator mass spectrometry (AMS) in the same ore samples for the first time. To ensure efficient extraction of both elements and isotopic equilibrium between the {sup 239}Pu in the ore and a {sup 242}Pu spike, we developed a new sample preparation protocol. AMS has clear advantages over previous methods because it achieves better discrimination against molecular interferences with higher sensitivity and shorter counting times. Measurements of {sup 236}U and {sup 239}Pu hold considerable promise as proxy indicators of neutron flux and uranium concentration.

  12. Separation of protactinium in the reaction of 60 MeV/nucleon 18O ions with natural uranium

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The activities of protactinium were produced by the multi-nucleontransfer reactions in bombardment of the natural uranium with 60 MeV/nucleon 1sOions. A simple, relatively fast radiochemical procedure was used for extraction sep-aration of protactinium from the uranium and a variety of reaction products using1-phenyl-3-methyl-4-benzoyl-5-pyrazolone and tri-iso-octylamine as extractants. Theγ ray spectrum of the separated protactinium fractions showed that the protactiniumcould be separated from all of the main impurity elements. The decontaminationfactors of the uranium and the main reaction products produced in the reaction aregiven.``

  13. A study of function mechanism of hemxamethyl tetra-amine in gelation process of uranium

    Institute of Scientific and Technical Information of China (English)

    GUO Wenli; LIANG Tongxiang; ZHAO Xingyu; HAO Shaochang; FU Xiaoming

    2006-01-01

    The UO2 ceramic microspheres are the most important materials in the spherical fuel elements for high temperature reactor (HTR). A process for preparation of UO2 kernels known as total gelation process of uranium (TGU) was developed as the production process of 10 mW HTR at Tsinghua University. The TGU process is based on the traditional sol-gel process, external gelation process and internal gelation process of uranium (EGU and IGU), which implies that the gelation action is initiated both by ammonia out of the gel particles and hemxamethyl tetra-amine (HMTA) inside the gel particles. The gelation behavior and the properties of uranium microspheres were investigated of the solution with and without HMTA. It is observed that good spherical particles can be obtained without HMTA in the sol, which indicates a more controllable and industrialized route will be set up. Contrasts between this route and the traditional EGU were also listed .

  14. Preliminary Study of Lead-Oxide Cooled Fast Reactor with Natural Uranium as an Input Fuel with Reactor Shuffling Strategy

    Science.gov (United States)

    Mahmudah, Rida SN; Su’ud, Zaki

    2017-01-01

    A preliminary study of lead-oxide cooled fast reactor with natural uranium as an input fuel using reactor shuffling strategy has been conducted. In this study, reactor core is divided into four zone with the same volume, each zone use different uranium enrichment. The enrichment number is estimated so that in the end of reactor’s operation, we only need to add natural uranium as the fresh input fuel. This study used UN-PuN as the fuel and lead oxide as the coolant. Several parameter studies have been conducted to determine the most suitable input condition. It is confirmed in this study that with fuel : cladding : coolant ratio of 53 : 10 : 37, and uranium enrichment in the first to the fourth zone of 0%, 6.25%, 7.5% and 8%, respectively, the reactor can operate as long as 20 years of operation with terminal k-eff of 1.0004.

  15. Doses and risks from uranium are not increased significantly by interactions with natural background photon radiation.

    Science.gov (United States)

    Tanner, R J; Eakins, J S; Jansen, J T M; Harrison, J D

    2012-08-01

    The impact of depleted uranium (DU) on human health has been the subject of much conjecture. Both the chemical and radiological aspects of its behaviour in the human body have previously been investigated in detail, with the radiological impact being assumed to be linked to the alpha decay of uranium. More recently, it has been proposed that the accumulation in tissue of high-Z materials, such as DU, may give rise to enhanced local energy deposition in the presence of natural background photon radiation due to the high photoelectric interaction cross sections of high-Z atoms. It is speculated that, in addition to producing short-range photoelectrons, these events will be followed by intense Auger and Coster-Kronig electron emission, thereby causing levels of cell damage that are unaccounted for in conventional models of radiological risk. In this study, the physical and biological bases of these claims are investigated. The potential magnitudes of any effect are evaluated and discussed, and compared with the risks from other radiological or chemical hazards. Monte Carlo calculations are performed to estimate likely energy depositions due to the presence of uranium in human tissues in photon fields: whole body doses, organ doses in anthropomorphic phantoms and nano-/micro-dosimetric scenarios are each considered. The proposal is shown generally to be based on sound physics, but overall the impact on human health is expected to be negligible.

  16. Linking AS, SE, V, and MN Behavior to Natural Biostimulated Uranium Cycling

    Energy Technology Data Exchange (ETDEWEB)

    Keimowitz, Alison [Vassar College, Poughkeepsie, NY (United States); Ranville, James [Colorado School of Mines, Golden, CO (United States); Mailloux, Brian [Barnard College, New York, NY (United States); Figueroa, Linda [Colorado School of Mines, Golden, CO (United States)

    2016-03-16

    The project “Linking As, Se, V, and Mn behavior to Natural and Biostimulated Uranium Cycling” successfully investigated Arsenic cycling the Rifle Colorado IFRC. This project trained undergraduate and graduate students at the Colorado School of Mines, Vassar College, and Barnard College. This resulted in both undergraduate theses and a PhD thesis and multiple publications. The science was highly successful and we were able to test the main hypotheses. We have shown that (H1) under reducing conditions that promote uranium immobilization arsenic is readily mobilized, that (H2) thioarsenic species are abundant during this mobilization, and (H3) we have examined arsenic mobilization for site sediment. At the Rifle IFRC Acetate was added during experiments to immobilize Uranium. These experiments successfully immobilized uranium but unfortunately would mobilize arsenic. We developed robust sampling and analysis methods for thioarsenic species. We showed that the mobilization occurred under sulfate reducing conditions and the majority of the arsenic was in the form of thioarsenic species. Previous studies had predicted the presence of thioarsenic species but this study used robust field and laboratory methods to quantitatively determine the presence of thioarsenic species. During stimulation in wells with high arsenic the primary species were trithioarsenate and dithioarsenate. In wells with low levels of arsenic release thioarsenates were absent or minor components. Fortunately after the injection of acetate ended the aquifer would become less reducing and the arsenic concentrations would decrease to pre-injection levels. In aquifers where organic carbon is being added as a remedial method or as a contaminant the transient mobility of arsenic during sulfidogenesis should be considered especially in sulfate rich aquifers as this could impact downgradient water quality.

  17. Natural radioactivity in commercial granites extracted near old uranium mines: scientific, economic and social impact of disinformation.

    Science.gov (United States)

    Pereira, Dolores; Pereira, Alcides; Neves, Luis

    2015-04-01

    The study of radioactivity in natural stones is a subject of great interest from different points of view: scientific, social and economic. Several previous studies have demonstrated that the radioactivity is dependent, not only on the uranium content, but also on the structures, textures, minerals containing the uranium and degree of weathering of the natural stone. Villavieja granite is extracted in a village where uranium mining was an important activity during the 20th century. Today the mine is closed but the granite is still extracted. Incorrect information about natural radioactivity given to natural stone users, policy makers, construction managers and the general public has caused turmoil in the media for many years. This paper considers problems associated with the communication of reliable information, as well as uncertainties, on natural radioactivity to these audiences.

  18. Monte Carlo modeling of recrystallization processes in α-uranium

    Science.gov (United States)

    Steiner, M. A.; McCabe, R. J.; Garlea, E.; Agnew, S. R.

    2017-08-01

    Starting with electron backscattered diffraction (EBSD) data obtained from a warm clock-rolled α-uranium deformation microstructure, a Potts Monte Carlo model was used to simulate static site-saturated recrystallization and test which recrystallization nucleation conditions within the microstructure are best validated by experimental observations. The simulations support prior observations that recrystallized nuclei within α-uranium form preferentially on non-twin high-angle grain boundary sites at 450 °C. They also demonstrate, in a new finding, that nucleation along these boundaries occurs only at a highly constrained subset of sites possessing the largest degrees of local deformation. Deformation in the EBSD data can be identified by the Kernel Average Misorientation (KAM), which may be considered as a proxy for the local geometrically necessary dislocation (GND) density.

  19. Uranium removal from groundwater by natural clinoptilolite zeolite: Effects of pH and initial feed concentration

    Energy Technology Data Exchange (ETDEWEB)

    Camacho, Lucy Mar [Department of Chemical Engineering, New Mexico State University, P.O. Box 30001, MSC 3805, Las Cruces, NM 88003 (United States); Deng, Shuguang, E-mail: sdeng@nmsu.edu [Department of Chemical Engineering, New Mexico State University, P.O. Box 30001, MSC 3805, Las Cruces, NM 88003 (United States); Parra, Ramona R. [Physical Science Laboratory, New Mexico State University, P.O. Box 30001, MSC 3805, Las Cruces, NM 88003 (United States)

    2010-03-15

    Adsorption of uranium (VI) on a natural clinoptilolite zeolite from Sweetwater County, Wyoming was investigated. Batch experiments were conducted to study the effects of pH and initial feed concentrations on uranium removal efficiency. It was found that the clinoptilolite can neutralize both acidic and low basic water solutions through its alkalinity and ion-exchange reactions with U within the solution, and adsorption of uranium (VI) species on clinoptilolite not only depends on the pH but also the initial feed concentration. The highest uranium removal efficiency (95.6%) was obtained at initial uranium concentration of 5 mg/L and pH 6.0. The Langmuir adsorption isotherm model correlates well with the uranium adsorption equilibrium data for the concentration range of 0.1-500 mg/L. From the experimental data obtained in this work, it was found that the zeolite sample investigated in this work is a mixture of clinoptilolite-Na zeolite and mineral impurities with a relatively large specific surface area (BET of 18 m{sup 2}/g) and promising adsorption properties for uranium removal from contaminated water.

  20. Environmental assessment of remedial action at the Naturita uranium processing site near Naturita, Colorado: Revision 5

    Energy Technology Data Exchange (ETDEWEB)

    1994-10-01

    Title 1 of the Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978, Public Law (PL) 95-604, authorized the US Department of Energy (DOE) to perform remedial action at the inactive Naturita, Colorado, uranium processing site to reduce the potential health effects from the radioactive materials at the site and at vicinity properties associated with the site. Title 2 of the UMTRCA authorized the US Nuclear Regulatory Commission (NRC) or agreement state to regulate the operation and eventual reclamation of active uranium processing sites. The uranium mill tailings at the site were removed and reprocessed from 1977 to 1979. The contaminated areas include the former tailings area, the mill yard, the former ore storage area, and adjacent areas that were contaminated by uranium processing activities and wind and water erosion. The Naturita remedial action would result in the loss of 133 acres (ac) of contaminated soils at the processing site. If supplemental standards are approved by the NRC and the state of Colorado, approximately 112 ac of steeply sloped contaminated soils adjacent to the processing site would not be cleaned up. Cleanup of this contamination would have adverse environmental consequences and would be potentially hazardous to remedial action workers.

  1. Comparison of potential radiological consequences from a spent-fuel repository and natural uranium deposits

    Energy Technology Data Exchange (ETDEWEB)

    Wick, O.J.; Cloninger, M.O.

    1980-09-01

    A general criterion has been suggested for deep geological repositories containing spent fuel - the repositories should impose no greater radiological risk than due to naturally occurring uranium deposits. The following analysis investigates the rationale of that suggestion and determines whether current expectations of spent-fuel repository performance are consistent with such a criterion. In this study, reference spent-fuel repositories were compared to natural uranium-ore deposits. Comparisons were based on intrinsic characteristics, such as radionuclide inventory, depth, proximity to aquifers, and regional distribution, and actual and potential radiological consequences that are now occurring from some ore deposits and that may eventually occur from repositories and other ore deposits. The comparison results show that the repositories are quite comparable to the natural ore deposits and, in some cases, present less radiological hazard than their natural counterparts. On the basis of the first comparison, placing spent fuel in a deep geologic repository apparently reduces the hazard from natural radioactive materials occurring in the earth's crust by locating the waste in impermeable strata without access to oxidizing conditions. On the basis of the second comparison, a repository constructed within reasonable constraints presents no greater hazard than a large ore deposit. It is recommended that if the naturally radioactive environment is to be used as a basis for a criterion regarding repositories, then this criterion should be carefully constructed. The criterion should be based on the radiological quality of the waters in the immediate region of a specific repository, and it should be in terms of an acceptable potential increase in the radiological content of those waters due to the existence of the repository.

  2. INTRAVAL phase 2, test case 8. Alligator Rivers Natural Analogue - Modelling of uranium transport in the weathered zone at Koongarra (Australia). Progress report

    NARCIS (Netherlands)

    van der Weerd H; Hassanizadeh SM; Richardson-van der Poel MA; LBG

    1993-01-01

    A study of uranium transport in the Koongarra site of Alligator Rivers Uranium deposit (Australia) is carried out. The analysis of the solid phase uranium concentration measured at various depths provides a useful picture of the dispersion process. Results of this analysis seem to support the

  3. INTRAVAL phase 2, test case 8. Alligator Rivers Natural Analogue - Modelling of uranium transport in the weathered zone at Koongarra (Australia). Progress report

    NARCIS (Netherlands)

    van der Weerd H; Hassanizadeh SM; Richardson-van der Poel MA; LBG

    1993-01-01

    A study of uranium transport in the Koongarra site of Alligator Rivers Uranium deposit (Australia) is carried out. The analysis of the solid phase uranium concentration measured at various depths provides a useful picture of the dispersion process. Results of this analysis seem to support the hypo

  4. Investigation of sulphur isotope variation due to different processes applied during uranium ore concentrate production.

    Science.gov (United States)

    Krajkó, Judit; Varga, Zsolt; Wallenius, Maria; Mayer, Klaus; Konings, Rudy

    The applicability and limitations of sulphur isotope ratio as a nuclear forensic signature have been studied. The typically applied leaching methods in uranium mining processes were simulated for five uranium ore samples and the n((34)S)/n((32)S) ratios were measured. The sulphur isotope ratio variation during uranium ore concentrate (UOC) production was also followed using two real-life sample sets obtained from industrial UOC production facilities. Once the major source of sulphur is revealed, its appropriate application for origin assessment can be established. Our results confirm the previous assumption that process reagents have a significant effect on the n((34)S)/n((32)S) ratio, thus the sulphur isotope ratio is in most cases a process-related signature.

  5. Natural Radioactivity in Soil and Water from Likuyu Village in the Neighborhood of Mkuju Uranium Deposit

    Directory of Open Access Journals (Sweden)

    Najat K. Mohammed

    2013-01-01

    Full Text Available The discovery of high concentration uranium deposit at Mkuju, southern part of Tanzania, has brought concern about the levels of natural radioactivity at villages in the neighborhood of the deposit. This study determined the radioactivity levels of 30 soil samples and 20 water samples from Likuyu village which is 54 km east of the uranium deposit. The concentrations of the natural radionuclides 238U, 232Th, and 40K were determined using low level gamma spectrometry of the Tanzania Atomic Energy Commission (TAEC Laboratory in Arusha. The average radioactivity concentrations obtained in soil samples for 238U (51.7 Bq/kg, 232Th (36.4 Bq/kg, and 40K (564.3 Bq/kg were higher than the worldwide average concentrations value of these radionuclides reported by UNSCEAR, 2000. The average activity concentration value of 238U (2.35 Bq/L and 232Th (1.85 Bq/L in water samples was similar and comparable to their mean concentrations in the control sample collected from Nduluma River in Arusha.

  6. Uranium hexafluoride: Safe handling, processing, and transporting: Conference proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Strunk, W.D.; Thornton, S.G. (eds.)

    1988-01-01

    This conference seeks to provide a forum for the exchange of information and ideas of the safety aspects and technical issue related to the handling of uranium hexafluoride. By allowing operators, engineers, scientists, managers, educators, and others to meet and share experiences of mutual concern, the conference is also intended to provide the participants with a more complete knowledge of technical and operational issues. The topics for the papers in the proceedings are widely varied and include the results of chemical, metallurgical, mechanical, thermal, and analytical investigations, as well as the developed philosophies of operational, managerial, and regulatory guidelines. Papers have been entered individually into EDB and ERA. (LTN)

  7. Uranium industry in Canada

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    Current state of uranium industry in Canada has been considered. It is shown that in Canada, which is the major supplier of uranium, new methods of prospecting, mining and processing of uranium are developed and the old ones are improved. Owing to automation and mechanization a higher labour productivity in uranium ore mining is achieved. The uranium industry of Canada can satisfy the future demands in uranium but introduction of any new improvement will depend completely on the rate of nuclear power development.

  8. A new process for the fractionation of uranium; Un nuevo procedimiento para el fraccionamiento de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Costas, E.; Baselga, B.; Tarin, F.

    2015-07-01

    We propose a new biological process for uranium isotopic fractionation based on Chlamydomonas cf. fonticola (microalgae) isolated from a pond extremely contaminated by uranium (. 25 ppm) from the ENUSA mine in Saelices (Salamanca, Spain) and genetically improved. The metabolic activity of this genetically improved ChlSPGI strain allows recover 115 mg of U per gram of micoralgal biomass in a short time (because this strain complete their cell cycle in . 24 hours). During this process ChlSPGI microalgae selectively captures {sup 2}35U conducting an isotopic enrichment of {sup 2}35U ({sup 2}35U δ = + 3,983%). (Author)

  9. Uranium mill tailings: nuclear waste and natural laboratory for geochemical and radioecological investigations

    Science.gov (United States)

    Landa, Edward R.

    2004-01-01

    Uranium mill tailings (UMT) are a high volume, low specific activity radioactive waste typically disposed in surface impoundments. This review focuses on research on UMT and related earth materials during the past decade relevant to the assessment of: (1) mineral hosts of radionuclides; (2) the use of soil analogs in predicting long-term fate of radionuclides; (3) microbial and diagenetic processes that may alter radionuclide mobility in the surficial environment; (4) waste-management technologies to limit radionuclide migration; and (5) the impact of UMT on biota.

  10. Uranium mill tailings: nuclear waste and natural laboratory for geochemical and radioecological investigations.

    Science.gov (United States)

    Landa, Edward R

    2004-01-01

    Uranium mill tailings (UMT) are a high volume, low specific activity radioactive waste typically disposed in surface impoundments. This review focuses on research on UMT and related earth materials during the past decade relevant to the assessment of: (1) mineral hosts of radionuclides; (2) the use of soil analogs in predicting long-term fate of radionuclides; (3) microbial and diagenetic processes that may alter radionuclide mobility in the surficial environment; (4) waste-management technologies to limit radionuclide migration; and (5) the impact of UMT on biota.

  11. Bioaccumulation and biological effects in the earthworm Eisenia fetida exposed to natural and depleted uranium

    Energy Technology Data Exchange (ETDEWEB)

    Giovanetti, Anna, E-mail: anna.giovanetti@enea.i [ENEA, Institute of Radiation Protection, CR Casaccia Via Anguillarese 301, 00123 Rome (Italy); Fesenko, Sergey [International Atomic Energy Agency (IAEA), Agency' s Laboratories Seibersdorf, A-2444 Seibersdorf (Austria); Cozzella, Maria L. [ENEA, National Institute for Metrology of Ionizing Radiation, CR Casaccia Via Anguillarese 301, 00123 Rome (Italy); Asencio, Lisbet D. [Centro de Estudios Ambientales, Carretera a Castillo de Jagua, CP. 59350 C. Nuclear, Cienfuegos (Cuba); Sansone, Umberto [International Atomic Energy Agency (IAEA), Agency' s Laboratories Seibersdorf, A-2444 Seibersdorf (Austria)

    2010-06-15

    The accumulations of both natural (U) and depleted (DU) uranium in the earthworms (Eisenia fetida) were studied to evaluate corresponding biological effects. Concentrations of metals in the experimental soil ranged from 1.86 to 600 mg kg{sup -1}. Five biological endpoints: mortality, animals' weight increasing, lysosomal membrane stability by measuring the neutral red retention time (the NRRT), histological changes and genetic effects (Comet assay) were used to evaluate biological effects in the earthworms after 7 and 28 days of exposure. No effects have been observed in terms of mortality or weight reduction. Cytotoxic and genetic effects were identified at quite low U concentrations. For some of these endpoints, in particular for genetic effects, the dose (U concentration)-effect relationships have been found to be non-linear. The results have also shown a statistically significant higher level of impact on the earthworms exposed to natural U compared to depleted U.

  12. The capitalist world aggregate supply and demand model for natural uranium

    Energy Technology Data Exchange (ETDEWEB)

    Amavilah, V.H.S. [Arizona Univ., Tucson, AZ (United States). Dept. of Mining and Geological Engineering]|[Ore Body Engineering Ltd., Tucson, AZ (United States)

    1995-07-01

    Seemingly unrelated regression associating U supply and demand to own price, net nuclear electric consumption, generating capacity, competing fuel prices, and electricity prices is postulated. Coal prices are found to influence uranium price significantly. Composite energy prices affect uranium demand via either nuclear electric consumption or nuclear generating capacity. Electricity prices affect uranium demand directly in a negative fashion. (author).

  13. Radon as a natural tracer for gas transport within uranium waste rock piles.

    Science.gov (United States)

    Silva, N C; Chagas, E G L; Abreu, C B; Dias, D C S; Lopez, D; Guerreiro, E T Z; Alberti, H L C; Braz, M L; Branco, O; Fleming, P

    2014-07-01

    Acid mine drainage (AMD) has been identified as the main cause for outflow of acid water and radioactive/non-radioactive contaminants. AMD encompasses pyrites oxidation when water and oxygen are available. AMD was identified in uranium waste rock piles (WRPs) of Indústrias Nucleares do Brasil-Caldas facility (Brazilian uranium mine), resulting in high costs for water treatment. AMD reduction is the main challenge, and scientific investigation has been conducted to understand oxygen and water transportation within WRPs, where 222Rn is used as natural tracer for oxygen transportation. The study consists of soil radon gas mapping in the top layer of WRP4 using active soil gas pumping, radon adsorption in active charcoal and 222Rn determination using high-resolution gamma-ray spectrometry. A sampling network of 71 points was built where samples were collected at a depth of 40 cm. Soil radon gas concentration ranged from 33.7 to 1484.2 kBq m(-3) with mean concentration of 320.7±263.3 kBq m(-3).

  14. Uranium(IV) adsorption by natural organic matter in anoxic sediments

    Energy Technology Data Exchange (ETDEWEB)

    Bone, Sharon E.; Dynes, James J.; Cliff, John; Bargar, John R.

    2017-01-09

    Uranium is an important carbon-free fuel source and environmental contaminant that accumulates in the tetravalent state, U(IV), in anoxic sediments, such as ore deposits, marine basins, and contaminated aquifers. However, little is known about the speciation of U(IV) in low-temperature geochemical environments, inhibiting the development of a conceptual model of U behavior. Until recently, U(IV) was assumed to exist predominantly as the sparingly soluble mineral uraninite (UO2+x) in anoxic sediments; however, studies now show that this is not often the case. Yet a model of U(IV) speciation in the absence of mineral formation under field-relevant conditions has not yet been developed. Uranium(IV) speciation controls its reactivity, particularly its susceptibility to oxidative mobilization, impacting its distribution and toxicity. Here we show adsorption to organic carbon and organic carbon-coated clays dominate U(IV) speciation in an organic-rich natural substrate under field-relevant conditions. Whereas previous research assumed that U(IV) speciation is dictated by the mode of reduction (i.e., whether reduction is mediated by microbes or by inorganic reductants), our results demonstrate that mineral formation can be diminished in favor of adsorption, regardless of reduction pathway. Projections of U transport and bioavailability, and thus its threat to human and ecosystem health, must consider U(IV) adsorption to organic matter within the sediment environment.

  15. Studying uranium migration in natural environment: experimental approach and geochemical modeling; Etude de la migration de l'uranium en milieu naturel: approche experimentale et modelisation geochimique

    Energy Technology Data Exchange (ETDEWEB)

    Phrommavanh, V.

    2008-10-15

    The present study deals with characterizing uranium migration in a limited zone of Le Bouchet site, a former uranium ore treatment facility, which is dismantled and the rehabilitation of which is under process. Some wastes are packed in a rehabilitated disposal nearby, called the Itteville site. In the framework of the monitoring of the deposit environment (air, water, sediment) set by prefectorial decrees, a piezometer (PZPK) located downstream to the latter, has shown total dissolved uranium peaks each winter since the 1990's. PZPK collects both the interstitial water of a calcareous peat formation, between the surface and 3 m, and an alluvial aquifer near 6 m of depth. Firstly, a hydrogeochemical characterization of the site has evidenced the uranium source term, which is present in the peat soil near 0.8 m, hence excluding any leaching from the waste disposal. Actually, a few microparticles of uranium oxide and mixed uranium-thorium oxide have been detected, but they do not represent the major part of the source term. Secondly, water chemistry of the peat soil water and PZPK has been monitored every two months from 2004 to 2007 in order to understand the reasons of the seasonal fluctuations of [U]tot.diss.. Completed with geochemical modeling and a bacterial identification by 16S rDNA sequence analysis, water chemistry data showed an important sulfate-reducing bacterial activity in summertime, leading to reducing conditions and therefore, a total dissolved uranium content limited by the low solubility of uraninite U{sup IV}O{sub 2}(s). In wintertime, the latter bacterial activity being minimal and the effective pluviometry more important, conditions are more oxidant, which favors U(VI), more soluble, notably as the Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3}(aq) complex, evidenced by TRLFS. Finally, bacterial activity has been reproduced in laboratory in order to better characterize its impact on uranium solubility in the peat soil. Various parameters were tested

  16. Uranium conversion; Urankonvertering

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina [Swedish Defence Research Agency (FOI), Stockholm (Sweden)

    2006-03-15

    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{sub 6} and UF{sub 4} are present require equipment that is made of corrosion resistant material.

  17. Some economic aspects of natural uranium graphite gas reactor types. Present status and trends of costs in France; Quelques aspects economiques de la filiere uranium naturel - Graphite - gaz. Etat actuel et tendance des couts en France

    Energy Technology Data Exchange (ETDEWEB)

    Gaussens, J.; Tanguy, P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Leo, B. [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    The first part of this report defines the economic advantages of natural uranium fuels, which are as follows: the restricted number and relatively simple fabrication processes of the fuel elements, the low cost per kWh of the finished product and the reasonable capital investments involved in this type of fuel cycle as compared to that of enriched uranium. All these factors combine to reduce the arbitrary nature of cost estimates, which is particularly marked in the case of enriched uranium due to the complexity of its cycle and the uncertainties of plutonium prices). Finally, the wide availability of yellowcake, as opposed to the present day virtual monopoly of isotope separation, and the low cost of natural uranium stockpiling, offer appreciable guarantees in the way of security of supply and economic and political independence as compared with the use of enriched uranium. As far as overall capital investments are concerned, it is shown that, although graphite-gas reactor costs are higher than those of light water reactors in certain capacity ranges, the situation becomes far less clear when we start taking into account, in the interest of national independence, the cost of nuclear fuel production equipment in the case of each of these types of reactor. Finally, the marginal cost of the power capacity of a graphite-gas reactor is low and its technological limitations have receded (owing particularly to the use of prestressed concrete). It is a well known fact that the trend is now towards larger power station units, which means that the rentability of natural uranium graphite reactors as compared to other types of reactors will become more and more pronounced. The second section aims at presenting a realistic short and medium term view of the fuel, running, and investment costs of French natural uranium graphite gas, reactors. Finally, the economic goals which this type of reactor can reach in the very near future are given. It is thus shown that considerable

  18. Measurement system analysis (MSA) of the isotopic ratio for uranium isotope enrichment process control

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Josue C. de; Barbosa, Rodrigo A.; Carnaval, Joao Paulo R., E-mail: josue@inb.gov.br, E-mail: rodrigobarbosa@inb.gov.br, E-mail: joaocarnaval@inb.gov.br [Industrias Nucleares do Brasil (INB), Rezende, RJ (Brazil)

    2013-07-01

    Currently, one of the stages in nuclear fuel cycle development is the process of uranium isotope enrichment, which will provide the amount of low enriched uranium for the nuclear fuel production to supply 100% Angra 1 and 20% Angra 2 demands. Determination of isotopic ration n({sup 235}U)/n({sup 238}U) in uranium hexafluoride (UF{sub 6} - used as process gas) is essential in order to control of enrichment process of isotopic separation by gaseous centrifugation cascades. The uranium hexafluoride process is performed by gas continuous feeding in separation unit which uses the centrifuge force principle, establishing a density gradient in a gas containing components of different molecular weights. The elemental separation effect occurs in a single ultracentrifuge that results in a partial separation of the feed in two fractions: an enriched on (product) and another depleted (waste) in the desired isotope ({sup 235}UF{sub 6}). Industrias Nucleares do Brasil (INB) has used quadrupole mass spectrometry (QMS) by electron impact (EI) to perform isotopic ratio n({sup 235}U)/n({sup 238}U) analysis in the process. The decision of adjustments and change te input variables are based on the results presented in these analysis. A study of stability, bias and linearity determination has been performed in order to evaluate the applied method, variations and systematic errors in the measurement system. The software used to analyze the techniques above was the Minitab 15. (author)

  19. Processing of mixed uranium/refractory metal carbide fuels for high temperature space nuclear reactors

    Science.gov (United States)

    Knight, Travis; Anghaie, Samim

    2000-01-01

    Single phase, solid-solution mixed uranium/refractory metal carbides have been proposed as an advanced nuclear fuel for high performance, next generation space power and propulsion systems. These mixed carbides such as the pseudo-ternary, (U, Zr, Nb)C, hold significant promise because of their high melting points (typically greater than 3200 K), thermochemical stability in a hot hydrogen environment, and high thermal conductivity. However, insufficient test data exist under nuclear thermal propulsion conditions of temperature and hot hydrogen environment to fully evaluate their performance. Various compositions of (U, Zr, Nb)C were processed with 5% and 10% metal mole fraction of uranium. Stoichiometric samples were processed from the constituent carbide powders while hypostoichiometric samples with carbon-to-metal (C/M) ratios of 0.95 were processed from uranium hydride, graphite, and constituent refractory carbide powders. Processing techniques of cold pressing, sintering, and hot pressing were investigated to optimize the processing parameters necessary to produce dense (low porosity), homogeneous, single phase, solid-solution mixed carbide nuclear fuels for testing. This investigation was undertaken to evaluate and characterize the performance of these mixed uranium/refractory metal carbides for space power and propulsion applications. .

  20. Characterization of Natural Attenuation in a uranium-contaminated site by means of Induced Polarization Imaging

    Science.gov (United States)

    Flores Orozco, Adrián; Bücker, Matthias; Williams, Kenneth

    2014-05-01

    Field experiments at the U.S. Department of Energy's (DOE) Integrated Field Research Challenge site (IFRC) in Rifle, Colorado (USA) have repeatedly demonstrated the ability of microorganisms to reductively immobilize uranium (U) in U tailings-contaminated groundwater accompanying organic carbon amendment. At the same time, geophysical monitoring during such amendment experiments has proven that Induced Polarization (IP) datasets can provide valuable information regarding geochemical changes induced by stimulated microbial activity, such as precipitation of metallic minerals (e.g. FeS) and accumulation of reactive, electroactive ions (Fe[II]). Based on these findings, we present a novel, modified application of the IP imaging method. Specifically, we utilized an IP characterization approach to delineate areas where fluvially deposited organic material, within aquifer sediments, naturally stimulates the activity of subsurface microflora, leading to both the natural immobilization of uranium and accumulation of reduced end-products (minerals and pore fluids) capable of generating anomalous IP signatures. These so-called 'naturally reduced zones' (NRZ's) are characterized by elevated rates of microbial activity relative to sediments having a lower concentration of organic matter. As noted and based on our previous experiments at the site, the accumulation of metallic minerals represents suitable targets for the exploration with IP tomographic methods. Here, we explore the application of the IP imaging method for the characterization of NRZ's at the scale of the floodplain. We present imaging results obtained through the inversion of 70 independent lines distributed along the floodplain (~600 m2). Imaging results are validated through comparisons with lithological data obtained from wells drilled at the site and laboratory analysis of sediment and groundwater samples. Our results show the applicability of the IP method for characterizing regions of the subsurface having

  1. An Overview of Process Monitoring Related to the Production of Uranium Ore Concentrate

    Energy Technology Data Exchange (ETDEWEB)

    McGinnis, Brent [Innovative Solutions Unlimited, LLC

    2014-04-01

    Uranium ore concentrate (UOC) in various chemical forms, is a high-value commodity in the commercial nuclear market, is a potential target for illicit acquisition, by both State and non-State actors. With the global expansion of uranium production capacity, control of UOC is emerging as a potentially weak link in the nuclear supply chain. Its protection, control and management thus pose a key challenge for the international community, including States, regulatory authorities and industry. This report evaluates current process monitoring practice and makes recommendations for utilization of existing or new techniques for managing the inventory and tracking this material.

  2. PROCESS FOR DISSOLVING BINARY URANIUM-ZIRCONIUM OR ZIRCONIUM-BASE ALLOYS

    Science.gov (United States)

    Jonke, A.A.; Barghusen, J.J.; Levitz, N.M.

    1962-08-14

    A process of dissolving uranium-- zirconium and zircaloy alloys, e.g. jackets of fuel elements, with an anhydrous hydrogen fluoride containing from 10 to 32% by weight of hydrogen chloride at between 400 and 450 deg C., preferably while in contact with a fluidized inert powder, such as calcium fluoride is described. (AEC)

  3. Cell-metal interactions: A comparison of natural uranium to other common metals in renal cells and bone osteoblasts

    Energy Technology Data Exchange (ETDEWEB)

    Milgram, S. [Laboratoire Pierre Suee, CEA-CNRS UMR 9956, CEA/Saclay, 91191 Gif-sur-Yvette (France); Carriere, M. [Laboratoire Pierre Suee, CEA-CNRS UMR 9956, CEA/Saclay, 91191 Gif-sur-Yvette (France); Thiebault, C. [Laboratoire Pierre Suee, CEA-CNRS UMR 9956, CEA/Saclay, 91191 Gif-sur-Yvette (France); Berger, P. [Laboratoire Pierre Suee, CEA-CNRS UMR 9956, CEA/Saclay, 91191 Gif-sur-Yvette (France); Khodja, H. [Laboratoire Pierre Suee, CEA-CNRS UMR 9956, CEA/Saclay, 91191 Gif-sur-Yvette (France); Gouget, B. [Laboratoire Pierre Suee, CEA-CNRS UMR 9956, CEA/Saclay, 91191 Gif-sur-Yvette (France)]. E-mail: barbara.gouget@cea.fr

    2007-07-15

    Uranium acute intoxication has been documented to induce nephrotoxicity. Kidneys are the main target organs after short term exposures to high concentrations of the toxic, while chronic exposures lead to its accumulation in the skeleton. In this paper, chemical toxicity of uranium is investigated for rat osteoblastic bone cells and compared to results previously obtained on renal cells. We show that bone cells are less sensitive to uranium than renal cells. The influence of the chemical form on U cytotoxicity is demonstrated. For both cell types, a comparison of uranium toxicity with other metals or metalloids toxicities (Mn, Ni, Co, Cu, Zn, Se and Cd) permits classification of Cd, Zn, Se{sup IV} and Cu as the most toxic and Ni, Se{sup VI}, Mn and U as the least toxic. Chemical toxicity of natural uranium proves to be far less than that of cadmium. To try to explain the differences in sensitivities observed between metals and different cell types, cellular accumulations in cell monolayers are quantified by inductively coupled plasma-mass spectroscopy (ICP-MS), function of time or function of dose: lethal doses which simulate acute intoxications and sub-lethal doses which are more realistic with regard to environmentally metals concentrations. In addition to being more resistant, bone cells accumulated much more uranium than did renal cells. Moreover, for both cell models, Mn, U-citrate and U-bicarbonate are strongly accumulated whereas Cu, Zn and Ni are weakly accumulated. On the other hand, a strong difference in Cd behaviour between the two cell types is shown: whereas Cd is very weakly accumulated in bone cells, it is very strongly accumulated in renal cells. Finally, elemental distribution of the toxics is determined on a cellular scale using nuclear microprobe analysis. For both renal and osteoblastic cells, uranium was accumulated in as intracellular precipitates similar to those observed previously by SEM/EDS.

  4. 77 FR 33253 - Regulatory Guide 8.24, Revision 2, Health Physics Surveys During Enriched Uranium-235 Processing...

    Science.gov (United States)

    2012-06-05

    ... COMMISSION Regulatory Guide 8.24, Revision 2, Health Physics Surveys During Enriched Uranium-235 Processing... CONTACT: Gregory Chapman, Uranium Enrichment Branch, Division of Fuel Cycle Safety and Safeguards, Office.... Introduction Revision 2 of Regulatory Guide 8.24, ``Health Physics Surveys During Enriched...

  5. Handbook of Natural Language Processing

    CERN Document Server

    Indurkhya, Nitin

    2010-01-01

    Provides a comprehensive, modern reference of practical tools and techniques for implementing natural language processing in computer systems. This title covers classical methods, empirical and statistical techniques, and various applications. It describes how the techniques can be applied to European and Asian languages as well as English

  6. Natural language processing with Java

    CERN Document Server

    Reese, Richard M

    2015-01-01

    If you are a Java programmer who wants to learn about the fundamental tasks underlying natural language processing, this book is for you. You will be able to identify and use NLP tasks for many common problems, and integrate them in your applications to solve more difficult problems. Readers should be familiar/experienced with Java software development.

  7. Processing of irradiated, enriched uranium fuels at the Savannah River Plant

    Energy Technology Data Exchange (ETDEWEB)

    Hyder, M L; Perkins, W C; Thompson, M C; Burney, G A; Russell, E R; Holcomb, H P; Landon, L F

    1979-04-01

    Uranium fuels containing /sup 235/U at enrichments from 1.1% to 94% are processed and recovered, along with neptunium and plutonium byproducts. The fuels to be processed are dissolved in nitric acid. Aluminum-clad fuels are disssolved using a mercury catalyst to give a solution rich in aluminum. Fuels clad in more resistant materials are dissolved in an electrolytic dissolver. The resulting solutions are subjected to head-end treatment, including clarification and adjustment of acid and uranium concentration before being fed to solvent extraction. Uranium, neptunium, and plutonium are separated from fission products and from one another by multistage countercurrent solvent extraction with dilute tri-n-butyl phosphate in kerosene. Nitric acid is used as the salting agent in addition to aluminum or other metal nitrates present in the feed solution. Nuclear safety is maintained through conservative process design and the use of monitoring devices as secondary controls. The enriched uranium is recovered as a dilute solution and shipped off-site for further processing. Neptunium is concentrated and sent to HB-Line for recovery from solution. The relatively small quantities of plutonium present are normally discarded in aqueous waste, unless the content of /sup 238/Pu is high enough to make its recovery desirable. Most of the /sup 238/Pu can be recovered by batch extraction of the waste solution, purified by counter-current solvent extraction, and converted to oxide in HB-Line. By modifying the flowsheet, /sup 239/Pu can be recovered from low-enriched uranium in the extraction cycle; neptunium is then not recovered. The solvent is subjected to an alkaline wash before reuse to remove degraded solvent and fission products. The aqueous waste is concentrated and partially deacidified by evaporation before being neutralized and sent to the waste tanks; nitric acid from the overheads is recovered for reuse.

  8. Dry uranium tetrafluoride process preparation using the uranium hexafluoride reconversion process effluents; Processo alternativo para obtencao de tetrafluoreto de uranio a partir de efluentes fluoretados da etapa de reconversao de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, Joao Batista da

    2008-07-01

    It is a well known fact that the use of uranium tetrafluoride allows flexibility in the production of uranium suicide and uranium oxide fuel. To its obtention there are two conventional routes, the one which reduces uranium from the UF{sub 6} hydrolysis solution with stannous chloride, and the hydro fluorination of a solid uranium dioxide. In this work we are introducing a third and a dry way route, mainly utilized to the recovery of uranium from the liquid effluents generated in the uranium hexafluoride reconversion process, at IPEN/CNEN-SP. Working in the liquid phase, this route comprises the recuperation of ammonium fluoride by NH{sub 4}HF{sub 2} precipitation. Working with the solid residues, the crystallized bifluoride is added to the solid UO{sub 2}, which comes from the U mini plates recovery, also to its conversion in a solid state reaction, to obtain UF{sub 4}. That returns to the process of metallic uranium production unity to the U{sub 3}Si{sub 2} obtention. This fuel is considered in IPEN CNEN/SP as the high density fuel phase for IEA-R1m reactor, which will replace the former low density U{sub 3}Si{sub 2}-Al fuel. (author)

  9. Uranium, depleted uranium, biological effects; Uranium, uranium appauvri, effets biologiques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    Physicists, chemists and biologists at the CEA are developing scientific programs on the properties and uses of ionizing radiation. Since the CEA was created in 1945, a great deal of research has been carried out on the properties of natural, enriched and depleted uranium in cooperation with university laboratories and CNRS. There is a great deal of available data about uranium; thousands of analyses have been published in international reviews over more than 40 years. This presentation on uranium is a very brief summary of all these studies. (author)

  10. Analysis and exploitation of bacterial population from natural uranium-rich soils: selection of a model specie; Analyse et exploitation des populations bacteriennes de sols riches en uranium: selection d'une espece modele

    Energy Technology Data Exchange (ETDEWEB)

    Mondani, L.

    2010-11-23

    It is well known that soils play a key role in controlling the mobility of toxic metals and this property is greatly influenced by indigenous bacterial communities. This study has been conducted on radioactive and controls soils, collected in natural uraniferous areas (Limousin). A physico-chemical and mineralogical analysis of soils samples was carried out.The structure of bacterial communities was estimated by Denaturing Gradient Gel Electrophoresis (DGGE). The community structure is remarkably more stable in the uranium-rich soils than in the control ones, indicating that uranium exerts a high selection from the soils was constructed and screened for uranium resistance in order to study bacteria-uranium interactions. Scanning electron microscopy revealed that a phylo-genetically diverse set of uranium-resistant species ware able to chelate uranium at the cell surface. (author) [French] On sait que les sols et les populations bacteriennes indigenes ont une influence sur la mobilite des metaux, donc sur leur toxicite. Cette etude a ete menee sur des sols uraniferes et controles collectes dans le Limousin (regions naturellement riches en uranium ). Une analyse physico-chimique et mineralogique des echantillons de sol a ete realisee. La structure des communautes bacteriennes a ete etudiee par electrophorese en gradient de denaturant (DGGE). La structure des communautes est remarquablement stable dans les sols uraniferes, ce qui indique que l'uranium exerce une forte pression de selection. D'autre part, une collection de bacteries cultivables a ete realisee a partir des sols, puis criblee pour la resistance a l'uranium, dans le but d'etudier les interactions entre bacteries et uranium. Des observations en Microscopie electronique a Balayage ont mis en evidence differents mecanismes de chelation de l'uranium a la surface cellulaire

  11. Natural arsenic and uranium accumulation and remobilization in different geological environments

    Energy Technology Data Exchange (ETDEWEB)

    Banning, Andre Wilhelm

    2012-03-05

    Despite the fact that both As and U represent geogenic trace elements potentially toxic to humans, little information is available on the development of their enrichments in German sediments and their potential impact on groundwater quality, let alone a systematic overview of the country's natural occurrences. This work aims at characterizing accumulation processes in aquifers actually or potentially affected by elevated concentrations of As and/or U, and their timings in geological history. The five selected study areas provide different geological and stratigraphical backgrounds. Identification of As and U sources, and structural derivation of their environmental reservoirs as well as remobilization mechanisms potentially resulting in trace element release to groundwater were assessed. Drinking water supply in Franconia/Northern Bavaria is dependent on groundwater extraction from terrestrial Upper Triassic sandstones where elevated concentrations of geogenic U and As exceeding German drinking water limitations were identified. Characterization of aquifer material in terms of geochemical and mineralogical composition, trace elements distribution on a microscale and their mineralogical fractionation and mobilization behaviour showed that uraniferous francolite/hematite inclusions within the aquifer sandstones (''active arkoses'') represent important sources for U and As in the study area. Francolite exhibits biologically, structurally and radiation-enhanced solubility; loss of both U and As during weathering was documented. Jurassic shallow marine Fe ores from the Upper Rhine Graben exhibit significant bulk As hosted in mainly goethite ooids slowly formed in times of condensed sedimentation. The study indicates that As accumulation was favoured over other potential contaminants, esp. heavy metals. Conditions for As accumulation varied during deposition, visible on a macro- (outcrop) as well as on a microscale (single Fe ooid). However, the

  12. Improving Natural Uranium Utilization By Using Thorium in Low Moderation PWRs - A Preliminary Neutronic Scoping Study

    Energy Technology Data Exchange (ETDEWEB)

    Gilles Youinou; Ignacio Somoza

    2010-10-01

    The Th-U fuel cycle is not quite self-sustainable when used in water-cooled reactors and with fuel burnups higher than a few thousand of MWd/t characteristic of CANDU reactors operating with a continuous refueling. For the other industrially mature water-cooled reactors (i.e. PWRs and BWRs) it is economically necessary that the fuel has enough reactivity to reach fuel burnups of the order of a few tens of thousand of MWd/t. In this particular case, an additional input of fissile material is necessary to complement the bred fissile U-233. This additional fissile material could be included in the form of Highly Enriched Uranium (HEU) at the fabrication of the Th-U fuel. The objective of this preliminary neutronic scoping study is to determine (1) how much HEU and, consequently, how much natural uranium is necessary in such Th-U fuel cycle with U recycling and (2) how much TRansUranics (TRU=Pu, Np, Am and Cm) are produced. These numbers are then compared with those of a standard UO2 PWR. The thorium reactors considered have a homogeneous hexagonal lattice made up of the same (Th-U)O2 pins. Furthermore, at this point, we are not considering the use of blankets inside or outside the core. The lattice pitch has been varied to estimate the effect of the water-to-fuel volume ratio, and light water as well as heavy water have been considered. For most cases, an average burnup at discharge of 45,000 MWd/t has been considered.

  13. Development of a Novel Depleted Uranium Treatment Process at Lawrence Livermore National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Gates-Anderson, D; Bowers, J; Laue, C; Fitch, T

    2007-01-22

    A three-stage process was developed at Lawrence Livermore National Laboratory to treat potentially pyrophoric depleted uranium metal wastes. The three-stage process includes waste sorting/rinsing, acid dissolution of the waste metal with a hydrochloric and phosphoric acid solution, and solidification of the neutralized residuals from the second stage with clay. The final product is a solid waste form that can be transported to and disposed of at a permitted low-level radioactive waste disposal site.

  14. Visual processing during natural reading

    Science.gov (United States)

    Weiss, Béla; Knakker, Balázs; Vidnyánszky, Zoltán

    2016-01-01

    Reading is a unique human ability that plays a pivotal role in the development and functioning of our modern society. However, its neural basis remains poorly understood since previous research was focused on reading words with fixed gaze. Here we developed a methodological framework for single-trial analysis of fixation onset-related EEG activity (FOREA) that enabled us to investigate visual information processing during natural reading. To reveal the effect of reading skills on orthographic processing during natural reading, we measured how altering the configural properties of the written text by modifying inter-letter spacing affects FOREA. We found that orthographic processing is reflected in FOREA in three consecutive time windows (120–175 ms, 230–265 ms, 345–380 ms after fixation onset) and the magnitude of FOREA effects in the two later time intervals showed a close association with the participants’ reading speed: FOREA effects were larger in fast than in slow readers. Furthermore, these expertise-driven configural effects were clearly dissociable from the FOREA signatures of visual perceptual processes engaged to handle the increased crowding (155–220 ms) as a result of decreasing letter spacing. Our findings revealed that with increased reading skills orthographic processing becomes more sensitive to the configural properties of the written text. PMID:27231193

  15. Novel Poly(imide dioxime) Sorbents: Development and testing for enhanced extraction of uranium from natural seawater

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sadananda; Brown, Suree S.; Mayes, Richard T.; Janke, Christopher J.; Tsouris, Costas; Kuo, Li-Jung; Gill, Gary A.; Dai, Sheng

    2016-04-09

    A new series of amidoxime-based polymer adsorbents were synthesized at the Oak Ridge National Laboratory (ORNL) by electron beam induced grafting of acrylonitrile and itaconic acid onto polyethylene fiber. Hydroxylamine derivatives of poly(acrylonitrile) (PAN) moiety are demonstrated to possess two kinds of functional groups: open-chain amidoxime and cyclic imide dioxime. The open-chain amidoxime is shown to convert to imide dioxime on heat treatment in the presence of an aprotic solvent, like dimethylsulfoxide (DMSO). The formation of amidoxime and imide dioxime was confirmed by 13-C CPMAS spectra. The adsorbents were evaluated for uranium adsorption efficiency at ORNL with simulated seawater spiked with 8 ppm uranium and 5 gallon seawater in a batch reactor, and in flow-through columns with natural seawater at the Marine Science Laboratory (MSL) of Pacific Northwest National Laboratory (PNNL) at Sequim Bay, WA. The DMSO-heat-treated sorbents adsorbed uranium as high as 4.48 g-U/kg-ads. from seawater. Experimental evidence is presented that the poly(imide dioxime) is primarily responsible for enhanced uranium adsorption capacity from natural seawater. The conjugated system in the imide dioxime ligand possesses increased electron donation ability, which is believed to significantly enhance the uranyl coordination in seawater

  16. Organic matter and containment of uranium and fissiogenic isotopes at the Oklo natural reactors

    Science.gov (United States)

    Nagy, B.; Gauthier-Lafaye, F.; Holliger, P.; Davis, D.W.; Mossman, D.J.; Leventhal, J.S.; Rigali, M.J.; Parnell, J.

    1991-01-01

    SOME of the Precambrian natural fission reactors at Oklo in Gabon contain abundant organic matter1,2, part of which was liquefied at the time of criticality and subsequently converted to a graphitic solid3,4. The liquid organic matter helps to reduce U(VI) to U(IV) from aqueous solutions, resulting in the precipitation of uraninite5. It is known that in the prevailing reactor environments, precipitated uraninite grains incorporated fission products. We report here observations which show that these uraninite crystals were held immobile within the resolidified, graphitic bitumen. Unlike water-soluble (humic) organic matter, the graphitic bituminous organics at Oklo thus enhanced radionu-clide containment. Uraninite encased in solid graphitic matter in the organic-rich reactor zones lost virtually no fissiogenic lan-thanide isotopes. The first major episode of uranium and lead migration was caused by the intrusion of a swarm of adjacent dolerite dykes about 1,100 Myr after the reactors went critical. Our results from Oklo imply that the use of organic, hydrophobic solids such as graphitic bitumen as a means of immobilizing radionuclides in pretreated nuclear waste warrants further investigation. ?? 1991 Nature Publishing Group.

  17. Sensitivity analysis of high resolution gamma-ray detection for safeguards monitoring at natural uranium conversion facilities

    Science.gov (United States)

    Dewji, S. A.; Croft, S.; Hertel, N. E.

    2017-03-01

    Under the policies proposed by recent International Atomic Energy Agency (IAEA) circulars and policy papers, implementation of safeguards exists when any purified aqueous uranium solution or uranium oxides suitable for isotopic enrichment or fuel fabrication exists. Under IAEA Policy Paper 18, the starting point for nuclear material under safeguards was reinterpreted, suggesting that purified uranium compounds should be subject to safeguards procedures no later than the first point in the conversion process. In response to this technical need, a combination of simulation models and experimental measurements were employed in previous work to develop and validate gamma-ray nondestructive assay monitoring systems in a natural uranium conversion plant (NUCP). In particular, uranyl nitrate (UO2(NO3)2) solution exiting solvent extraction was identified as a key measurement point (KMP). Passive nondestructive assay techniques using high resolution gamma-ray spectroscopy were evaluated to determine their viability as a technical means for drawing safeguards conclusions at NUCPs, and if the IAEA detection requirements of 1 significant quantity (SQ) can be met in a timely manner. Building upon the aforementioned previous validation work on detector sensitivity to varying concentrations of uranyl nitrate via a series of dilution measurements, this work investigates detector response parameter sensitivities to gamma-ray signatures of uranyl nitrate. The full energy peak efficiency of a detection system is dependent upon the sample, geometry, absorption, and intrinsic efficiency parameters. Perturbation of these parameters translates into corresponding variations of the 185.7 keV peak area of the 235U in uranyl nitrate. Such perturbations in the assayed signature impact the quality or versatility of the safeguards conclusions drawn. Given the potentially high throughput of uranyl nitrate in NUCPs, the ability to assay 1 SQ of material requires uncertainty «1%. Accounting for

  18. The feasibility study of small long-life gas cooled fast reactor with mixed natural Uranium/Thorium as fuel cycle input

    Science.gov (United States)

    Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Khairurrijal, Monado, Fiber; Sekimoto, Hiroshi

    2012-06-01

    A conceptual design study of Gas Cooled Fast Reactors with Modified CANDLE burn-up scheme has been performed. In this study, design GCFR with Helium coolant which can be continuously operated by supplying mixed Natural Uranium/Thorium without fuel enrichment plant or fuel reprocessing plant. The active reactor cores are divided into two region, Thorium fuel region and Uranium fuel region. Each fuel core regions are subdivided into ten parts (region-1 until region-10) with the same volume in the axial direction. The fresh Natural Uranium and Thorium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh natural Uranium/Thorium fuel. This concept is basically applied to all regions in both cores area, i.e. shifted the core of ith region into i+1 region after the end of 10 years burn-up cycle. For the next cycles, we will add only Natural Uranium and Thorium on each region-1. The calculation results show the reactivity reached by mixed Natural Uranium/Thorium with volume ratio is 4.7:1. This reactor can results power thermal 550 MWth. After reactor start-up the operation, furthermore reactor only needs Natural Uranium/Thorium supply for continue operation along 100 years.

  19. Uranium hexafluoride handling. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    The United States Department of Energy, Oak Ridge Field Office, and Martin Marietta Energy Systems, Inc., are co-sponsoring this Second International Conference on Uranium Hexafluoride Handling. The conference is offered as a forum for the exchange of information and concepts regarding the technical and regulatory issues and the safety aspects which relate to the handling of uranium hexafluoride. Through the papers presented here, we attempt not only to share technological advances and lessons learned, but also to demonstrate that we are concerned about the health and safety of our workers and the public, and are good stewards of the environment in which we all work and live. These proceedings are a compilation of the work of many experts in that phase of world-wide industry which comprises the nuclear fuel cycle. Their experience spans the entire range over which uranium hexafluoride is involved in the fuel cycle, from the production of UF{sub 6} from the naturally-occurring oxide to its re-conversion to oxide for reactor fuels. The papers furnish insights into the chemical, physical, and nuclear properties of uranium hexafluoride as they influence its transport, storage, and the design and operation of plant-scale facilities for production, processing, and conversion to oxide. The papers demonstrate, in an industry often cited for its excellent safety record, continuing efforts to further improve safety in all areas of handling uranium hexafluoride. Selected papers were processed separately for inclusion in the Energy Science and Technology Database.

  20. INTRAVAL phase 2, test case 8, Alligator Rivers Natural Analogue: Modelling of uranium transport in the weathered zone at Koongarra (Australia)

    Energy Technology Data Exchange (ETDEWEB)

    Van de Weerd, H.; Leijnse, A.; Hassanizadeh, S.M.; Richardson-van der Poel, M.A.

    1994-04-01

    The purpose of this study is to test the simulation package METROPOL, developed at RIVM to simulate transport of radionuclides over large time scales. At the Koongarra site secondary uranium mineralization and dispersed uranium is present from the surface down to the base of weathering. Field data are analyzed to choose a modelling approach, to estimate model inputs and to test model results. Field data show that three layers can be distinguished in the Koongarra area: (1) a top layer which is fully weathered, (2) an intermediate layer which is partially weathered (the transition zone) and (3) a lower layer which is unweathered. The groundwater velocities are largest in the transition zone which has been moving downward as the weathering process proceeds. The finite element code METROPOL has been adapted to account for the movement of the transition zone and to describe the dissolution of uranium in the orebody by a non-equilibrium relation. In simulations taking into account the downward movement of the transition zone, the dispersion patterns at all depths are simulated. These simulations result in a pseudo steady state situation. Despite the fact that the model results presented are not fully in agreement with the dispersion patterns, it is expected that the present situation may be obtained by changing some of the model parameters. In this study it was shown that over large timescales geologic processes may have an impact on the transport of radionuclides, and the movement of the transition zone will have an impact on the uranium concentration distribution. The simulation results are influenced by the parameters values, which are difficult to estimate for a period of some million years. The largest uncertainties are associated with the boundary conditions. Continuation of natural analogue studies in the framework of nuclear waste disposal research is highly recommended. 24 figs., 13 tabs., 2 appendices, 39 refs.

  1. Mineral-Water Interface Processes Affecting Uranium Fate in Contaminated Sediments

    Science.gov (United States)

    Catalano, J. G.

    2011-12-01

    Widespread uranium contamination of soil, sediments, and groundwater systems has resulted from mining activities, nuclear weapon production, and energy generation. The fate and transport of uranium in such systems is strongly affected by geochemical processes occurring at mineral-water interfaces. I will present a summary of the mineral-water interface processes found to affect uranium fate in example contaminated sediments at the U.S. Department of Energy's Hanford sites and in related model systems. Processes occurring under oxic conditions will be the primary focus of this talk as under these conditions uranium is most mobile and thus presents the greatest hazard. Three dominant solid-phase uranium species are observed in contaminated soil and sediments at the Hanford site: uranyl silicates, uranyl phosphates, and uranyl adsorbed to clays and iron oxides. In deep sediments, uranyl silicates are found in microfractures in feldspar grains, likely because slow diffusion in such fractures maintains a high silicate activity. Such silicates are also found in waste-impacted shallow sediments and soil; waste fluids or evaporative processes may have generated the silicate activity needed to produce such phases. Uranyl phosphates are less abundant, occurring primarily in shallow sediments exposed to P-bearing waste fluids. However, remediation approaches under consideration may produce substantial quantities of uranyl phosphates in the future. Adsorbed uranyl is dispersed throughout contaminated soils and shallow sediments and likely has the greatest potential for remobilization. Analogue studies show that precipitation of uranyl phosphates is rapid when such phases are supersaturated and that both homogeneous and heterogeneous nucleation may occur. Specific adsorption of uranyl to minerals is strongly affected by the presence of complexation anions. Carbonate suppresses uranyl adsorption but also forms uranyl-carbonate ternary surface complexes. At conditions below

  2. Idaho Chemical Processing Plant and Plutonium-Uranium Extraction Plant phaseout/deactivation study

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, M.W. [Westinghouse Idaho Nuclear Co., Idaho Falls, ID (United States); Thompson, R.J. [Westinghouse Hanford Co., Richland, WA (United States)

    1994-01-01

    The decision to cease all US Department of Energy (DOE) reprocessing of nuclear fuels was made on April 28, 1992. This study provides insight into and a comparison of the management, technical, compliance, and safety strategies for deactivating the Idaho Chemical Processing Plant (ICPP) at Westinghouse Idaho Nuclear Company (WINCO) and the Westinghouse Hanford Company (WHC) Plutonium-Uranium Extraction (PUREX) Plant. The purpose of this study is to ensure that lessons-learned and future plans are coordinated between the two facilities.

  3. Advances in natural language processing.

    Science.gov (United States)

    Hirschberg, Julia; Manning, Christopher D

    2015-07-17

    Natural language processing employs computational techniques for the purpose of learning, understanding, and producing human language content. Early computational approaches to language research focused on automating the analysis of the linguistic structure of language and developing basic technologies such as machine translation, speech recognition, and speech synthesis. Today's researchers refine and make use of such tools in real-world applications, creating spoken dialogue systems and speech-to-speech translation engines, mining social media for information about health or finance, and identifying sentiment and emotion toward products and services. We describe successes and challenges in this rapidly advancing area. Copyright © 2015, American Association for the Advancement of Science.

  4. The Alligator rivers natural analogue - Modelling of uranium and thorium migration in the weathered zone at Koongarra

    Energy Technology Data Exchange (ETDEWEB)

    Skagius, K.; Lindgren, M.; Boghammar, A.; Brandberg, F.; Pers, K.; Widen, H. [Kemakta, Stockholm (Sweden)

    1993-08-01

    The Koongarra Uranium Deposit in the Alligator Rivers Region in the Northern Territory of Australia is a natural analogue being investigated with the aim to contribute to the understanding of the scientific basis for the long term prediction of radionuclide migration within geological environments relevant to radioactive waste repositories. The dispersion of uranium and decay products in the weathered zone has been modelled with a simple advection-dispersion-reversible sorption model and with a model extended to also consider {alpha}-recoil and transfer of radionuclides between different mineral phases of the rock. The modelling work was carried out in several iterations, each including a review of available laboratory and field data, selection of the system to be modelled and suitable model, and a comparison of modelling results with field observations. Uranium concentrations in bulk rock calculated with the simple advection-dispersion- reversible sorption model were in fair agreement with observed data using parameter values within ranges recommended based on independent interpretations. The advection-dispersion-reversible sorption model is a large simplification of the system among other things because the partitioning of radionuclides between water and solid phase is described with a sorption equilibrium term only. Although the results from this study not are enough to validate simple performance assessment models in a strict sense, it has been shown that even simple models are able to describe the present day distribution of uranium in the weathered zone at Koongarra. 23 refs, 61 figs.

  5. Uranium(IV) adsorption by natural organic matter in anoxic sediments

    Energy Technology Data Exchange (ETDEWEB)

    Bone, Sharon E.; Dynes, James J.; Cliff, John; Bargar, John R.

    2017-01-09

    Uranium is an important fuel source and a global environmental contaminant. It accumulates in the tetravalent state, U(IV), in anoxic sediments, including ore deposits, marine basins, and contaminated aquifers. However, very little is known about the speciation of U(IV) in low temperature geochemical environments, inhibiting the development of a conceptual model of U behavior. Until recently, U(IV) was assumed to exist predominantly as the sparingly soluble mineral uraninite (UO2) in anoxic sediments; yet studies now show that UO2 is not often dominant in these environments. However, a model of U(IV) speciation under environmentally relevant conditions has not yet been developed. Here we show that complexes of U(IV) adsorb on organic carbon and organic carbon-coated clays in an organic-rich natural substrate under field-relevant conditions. Whereas previous research assumed that the U(IV) product depended on the reduction pathway, our results demonstrate that UO2 formation can be inhibited simply by decreasing the U:solid ratio. Thus, it is the number and type of surface ligands that controls U(IV) speciation subsequent to U(VI) reduction. Projections of U transport and bioavailability, and thus its threat to human and ecosystem health, must consider retention of U(IV) ions within the local sediment environment.

  6. Contribution for the derivation of a soil screening value (SSV for uranium, using a natural reference soil.

    Directory of Open Access Journals (Sweden)

    Ana Luisa Caetano

    Full Text Available In order to regulate the management of contaminated land, many countries have been deriving soil screening values (SSV. However, the ecotoxicological data available for uranium is still insufficient and incapable to generate SSVs for European soils. In this sense, and so as to make up for this shortcoming, a battery of ecotoxicological assays focusing on soil functions and organisms, and a wide range of endpoints was carried out, using a natural soil artificially spiked with uranium. In terrestrial ecotoxicology, it is widely recognized that soils have different properties that can influence the bioavailability and the toxicity of chemicals. In this context, SSVs derived for artificial soils or for other types of natural soils, may lead to unfeasible environmental risk assessment. Hence, the use of natural regional representative soils is of great importance in the derivation of SSVs. A Portuguese natural reference soil PTRS1, from a granitic region, was thereby applied as test substrate. This study allowed the determination of NOEC, LOEC, EC20 and EC50 values for uranium. Dehydrogenase and urease enzymes displayed the lowest values (34.9 and <134.5 mg U Kg, respectively. Eisenia andrei and Enchytraeus crypticus revealed to be more sensitive to uranium than Folsomia candida. EC50 values of 631.00, 518.65 and 851.64 mg U Kg were recorded for the three species, respectively. Concerning plants, only Lactuca sativa was affected by U at concentrations up to 1000 mg U kg(1. The outcomes of the study may in part be constrained by physical and chemical characteristics of soils, hence contributing to the discrepancy between the toxicity data generated in this study and that available in the literature. Following the assessment factor method, a predicted no effect concentration (PNEC value of 15.5 mg kg-1dw was obtained for U. This PNEC value is proposed as a SSV for soils similar to the PTRS1.

  7. Production of small uranium dioxide microspheres for cermet nuclear fuel using the internal gelation process

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Robert T [ORNL; Collins, Jack Lee [ORNL; Hunt, Rodney Dale [ORNL; Ladd-Lively, Jennifer L [ORNL; Patton, Kaara K [ORNL; Hickman, Robert [NASA Marshall Space Flight Center, Huntsville, AL

    2014-01-01

    The U.S. National Aeronautics and Space Administration (NASA) is developing a uranium dioxide (UO2)/tungsten cermet fuel for potential use as the nuclear cryogenic propulsion stage (NCPS). The first generation NCPS is expected to be made from dense UO2 microspheres with diameters between 75 and 150 m. Previously, the internal gelation process and a hood-scale apparatus with a vibrating nozzle were used to form gel spheres, which became UO2 kernels with diameters between 350 and 850 m. For the NASA spheres, the vibrating nozzle was replaced with a custom designed, two-fluid nozzle to produce gel spheres in the desired smaller size range. This paper describes the operational methodology used to make 3 kg of uranium oxide microspheres.

  8. Environmental assessment of remedial action at the Naturita Uranium Processing Site near Naturita, Colorado. Revision 4

    Energy Technology Data Exchange (ETDEWEB)

    1994-05-01

    The Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978, Public Law (PL) 95-604, authorized the US Department of Energy (DOE) to perform remedial action at the Naturita, Colorado, uranium processing site to reduce the potential health effects from the radioactive materials at the site and at vicinity properties associated with the site. The US Environmental Protection Agency (EPA) promulgated standards for the UMTRCA that contain measures to control the contaminated materials and to protect groundwater quality. Remedial action at the Naturita site must be performed in accordance with these standards and with the concurrence of the US Nuclear Regulatory Commission (NRC) and the state of Colorado. The proposed remedial action for the Naturita processing site is relocation of the contaminated materials and debris to either the Dry Flats disposal site, 6 road miles (mi) [10 kilometers (km)] to the southeast, or a licensed non-DOE disposal facility capable of handling RRM. At either disposal site, the contaminated materials would be stabilized and covered with layers of earth and rock. The proposed Dry Flats disposal site is on land administered by the Bureau of Land Management (BLM) and used primarily for livestock grazing. The final disposal site would cover approximately 57 ac (23 ha), which would be permanently transferred from the BLM to the DOE and restricted from future uses. The remedial action would be conducted by the DOE`s Uranium Mill Tailings Remedial Action (UMTRA) Project. This report discusses environmental impacts associated with the proposed remedial action.

  9. Conceptual design study on very small long-life gas cooled fast reactor using metallic natural Uranium-Zr as fuel cycle input

    Energy Technology Data Exchange (ETDEWEB)

    Monado, Fiber, E-mail: fiber.monado@gmail.com [Nuclear Physics and Biophysics Research Group, Dept. of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Bandung, Indonesia and Dept. of Physics, Faculty of Mathematics and Natural Sciences, Sriwijaya University (Indonesia); Ariani, Menik [Dept. of Physics, Faculty of Mathematics and Natural Sciences, Sriwijaya University (Indonesia); Su' ud, Zaki; Waris, Abdul; Basar, Khairul; Permana, Sidik [Nuclear Physics and Biophysics Research Group, Dept. of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Bandung (Indonesia); Aziz, Ferhat [National Nuclear Energy Agency of Indonesia (BATAN) (Indonesia); Sekimoto, Hiroshi [CRINES, Tokyo Institute of Technology, O-okoyama, Meguro-ku, Tokyo 152-8550 (Japan)

    2014-02-12

    A conceptual design study of very small 350 MWth Gas-cooled Fast Reactors with Helium coolant has been performed. In this study Modified CANDLE burn-up scheme was implemented to create small and long life fast reactors with natural Uranium as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. The core with metallic fuel based was subdivided into 10 regions with the same volume. The fresh Natural Uranium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh Natural Uranium fuel. This concept is basically applied to all axial regions. The reactor discharge burn-up is 31.8% HM. From the neutronic point of view, this design is in compliance with good performance.

  10. Conceptual design study on very small long-life gas cooled fast reactor using metallic natural Uranium-Zr as fuel cycle input

    Science.gov (United States)

    Monado, Fiber; Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Basar, Khairul; Aziz, Ferhat; Permana, Sidik; Sekimoto, Hiroshi

    2014-02-01

    A conceptual design study of very small 350 MWth Gas-cooled Fast Reactors with Helium coolant has been performed. In this study Modified CANDLE burn-up scheme was implemented to create small and long life fast reactors with natural Uranium as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. The core with metallic fuel based was subdivided into 10 regions with the same volume. The fresh Natural Uranium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh Natural Uranium fuel. This concept is basically applied to all axial regions. The reactor discharge burn-up is 31.8% HM. From the neutronic point of view, this design is in compliance with good performance.

  11. Preliminary Design Study of Medium Sized Gas Cooled Fast Reactor with Natural Uranium as Fuel Cycle Input

    Science.gov (United States)

    Meriyanti, Su'ud, Zaki; Rijal, K.; Zuhair, Ferhat, A.; Sekimoto, H.

    2010-06-01

    In this study a fesibility design study of medium sized (1000 MWt) gas cooled fast reactors which can utilize natural uranium as fuel cycle input has been conducted. Gas Cooled Fast Reactor (GFR) is among six types of Generation IV Nuclear Power Plants. GFR with its hard neuron spectrum is superior for closed fuel cycle, and its ability to be operated in high temperature (850° C) makes various options of utilizations become possible. To obtain the capability of consuming natural uranium as fuel cycle input, modified CANDLE burn-up scheme[1-6] is adopted this GFR system by dividing the core into 10 parts of equal volume axially. Due to the limitation of thermal hydraulic aspects, the average power density of the proposed design is selected about 70 W/cc. As an optimization results, a design of 1000 MWt reactors which can be operated 10 years without refueling and fuel shuffling and just need natural uranium as fuel cycle input is discussed. The average discharge burn-up is about 280 GWd/ton HM. Enough margin for criticallity was obtained for this reactor.

  12. [Content of natural uranium in the lichens and distribution of forms in the soil at the coastal area of Lakes Itkul and Sinara of Chelyabinsk region].

    Science.gov (United States)

    Polyudina, A L; Deryagin, V V; Levina, S G

    2014-01-01

    The distribution of natural uranium in soils superaquatic and transeluvial positions of the coastal landscape of lakes Itkul and Sinara, and liches on this site.The necessity of analysis of the content item in accordance with its form of occurrence in the natural environment. The peculiarities of the migration, accumulation and distribution of uranium in soils of the mountain areas of the watersheds of lakes Itkul and Sinara are found. Identified of specificity species lichens on the content of uranium in the substrate.

  13. Manhattan Project Technical Series The Chemistry of Uranium (I) Chapters 1-10

    Energy Technology Data Exchange (ETDEWEB)

    Rabinowitch, E. I. [Argonne National Laboratory (ANL), Argonne, IL (United States); Katz, J. J. [Argonne National Laboratory (ANL), Argonne, IL (United States)

    1946-09-30

    This constitutes Chapters 1 through 10. inclusive, of The Survey Volume on Uranium Chemistry prepared for the Manhattan Project Technical Series. Chapters are titled: Nuclear Properties of Uranium; Properties of the Uranium Atom; Uranium in Nature; Extraction of Uranium from Ores and Preparation of Uranium Metal; Physical Properties of Uranium Metal; Chemical Properties of Uranium Metal; Intermetallic Compounds and Alloy systems of Uranium; the Uranium-Hydrogen System; Uranium Borides, Carbides, and Silicides; Uranium Nitrides, Phosphides, Arsenides, and Antimonides.

  14. Multi-component reactive transport modeling of natural attenuation of an acid groundwater plume at a uranium mill tailings site

    Science.gov (United States)

    Zhu, Chen; Hu, Fang Q.; Burden, David S.

    2001-11-01

    Natural attenuation of an acidic plume in the aquifer underneath a uranium mill tailings pond in Wyoming, USA was simulated using the multi-component reactive transport code PHREEQC. A one-dimensional model was constructed for the site and the model included advective-dispersive transport, aqueous speciation of 11 components, and precipitation-dissolution of six minerals. Transport simulation was performed for a reclamation scenario in which the source of acidic seepage will be terminated after 5 years and the plume will then be flushed by uncontaminated upgradient groundwater. Simulations show that successive pH buffer reactions with calcite, Al(OH) 3(a), and Fe(OH) 3(a) create distinct geochemical zones and most reactions occur at the boundaries of geochemical zones. The complex interplay of physical transport processes and chemical reactions produce multiple concentration waves. For SO 42- transport, the concentration waves are related to advection-dispersion, and gypsum precipitation and dissolution. Wave speeds from numerical simulations compare well to an analytical solution for wave propagation.

  15. The effect of pH and natural microbial phosphatase activity on the speciation of uranium in subsurface soils

    Science.gov (United States)

    Beazley, Melanie J.; Martinez, Robert J.; Webb, Samuel M.; Sobecky, Patricia A.; Taillefert, Martial

    2011-10-01

    The biomineralization of U(VI) phosphate as a result of microbial phosphatase activity is a promising new bioremediation approach to immobilize uranium in both aerobic and anaerobic conditions. In contrast to reduced uranium minerals such as uraninite, uranium phosphate precipitates are not susceptible to changes in oxidation conditions and may represent a long-term sink for uranium in contaminated environments. So far, the biomineralization of U(VI) phosphate has been demonstrated with pure cultures only. In this study, two uranium contaminated soils from the Department of Energy Oak Ridge Field Research Center (ORFRC) were amended with glycerol phosphate as model organophosphate source in small flow-through columns under aerobic conditions to determine whether natural phosphatase activity of indigenous soil bacteria was able to promote the precipitation of uranium(VI) at pH 5.5 and 7.0. High concentrations of phosphate (1-3 mM) were detected in the effluent of these columns at both pH compared to control columns amended with U(VI) only, suggesting that phosphatase-liberating microorganisms were readily stimulated by the organophosphate substrate. Net phosphate production rates were higher in the low pH soil (0.73 ± 0.17 mM d -1) compared to the circumneutral pH soil (0.43 ± 0.31 mM d -1), suggesting that non-specific acid phosphatase activity was expressed constitutively in these soils. A sequential solid-phase extraction scheme and X-ray absorption spectroscopy measurements were combined to demonstrate that U(VI) was primarily precipitated as uranyl phosphate minerals at low pH, whereas it was mainly adsorbed to iron oxides and partially precipitated as uranyl phosphate at circumneutral pH. These findings suggest that, in the presence of organophosphates, microbial phosphatase activity can contribute to uranium immobilization in both low and circumneutral pH soils through the formation of stable uranyl phosphate minerals.

  16. Simultaneous determination of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry INa(Ti), in solid samples.; Determinacion de U (Natural), Th (Natural) y Ra-226 en diversos materiales, mediante espectrometria con INa (TI)

    Energy Technology Data Exchange (ETDEWEB)

    Salvador, S.; Navarro, T.; Alvarez, A.

    1991-07-01

    A method has been developed to determine activities of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry. The measurement system has been calibrated using standards specially prepared at the laboratory. It is necessary to assume secular equilibrium in the samples, between Ra-226 and Th-232 and its daughters nuclides, and between U-238 and its immediate daughter Th-234, as the photo peaks measured are those of the daughters. The results obtained indicate that this method can of ter replace the radiochemical techniques used to measure activities in this type of sample. The method has been successfully used to determine these natural isotopes in samples from uranium mills. (Author) 9 refs.

  17. Migration behavior of naturally occurring radionuclides at the Nopal I uranium deposit, Chihuahua, Mexico

    Science.gov (United States)

    Prikryl, James D.; Pickett, David A.; Murphy, William M.; Pearcy, English C.

    1997-04-01

    Oxidation of pyrite at the Nopal I uranium deposit, Peña Blanca district, Chihuahua, Mexico has resulted in the formation of Fe-oxides/hydroxides. Anomalous U concentrations (i.e. several hundred to several thousand ppm) measured in goethite, hematite, and amorphous Fe-oxyhydroxides in a major fracture that crosscuts the deposit and the absence of U minerals in the fracture suggest that U was retained during secondary mineral growth or sorbed on mineral surfaces. Mobilization and transport of U away from the deposit is suggested by decreasing U concentrations in fracture-infilling materials and in goethite and hematite with distance from the deposit. Greater than unity {234U}/{238U} activity ratios measured in fracture-infilling materials indicate relatively recent ( < 1 Ma) U uptake from fluids that carried excess 234U. Systematic decreases in {234U}/{238U} activity ratios of fracture materials with distance from the deposit suggest a multistage mobilization process, such as remobilization of U from 234U-enriched infill minerals or differential or diminished transport of U-bearing solutions containing excess 234U.

  18. Wetland and Sensitive Species Survey Report for Y-12: Proposed Uranium Processing Facility (UPF)

    Energy Technology Data Exchange (ETDEWEB)

    Giffen, N.; Peterson, M.; Reasor, S.; Pounds, L.; Byrd, G.; Wiest, M. C.; Hill, C. C.

    2009-11-01

    This report summarizes the results of an environmental survey conducted at sites associated with the proposed Uranium Processing Facility (UPF) at the Y-12 National Security Complex in September-October 2009. The survey was conducted in order to evaluate potential impacts of the overall project. This project includes the construction of a haul road, concrete batch plant, wet soil storage area and dry soil storage area. The environmental surveys were conducted by natural resource experts at ORNL who routinely assess the significance of various project activities on the Oak Ridge Reservation (ORR). Natural resource staff assistance on this project included the collection of environmental information that can aid in project location decisions that minimize impacts to sensitive resource such as significant wildlife populations, rare plants and wetlands. Natural resources work was conducted in various habitats, corresponding to the proposed areas of impact. Thc credentials/qualifications of the researchers are contained in Appendix A. The proposed haul road traverses a number of different habitats including a power-line right-of-way. wetlands, streams, forest and mowed areas. It extends from what is known as the New Salvage Yard on the west to the Polaris Parking Lot on the east. This haul road is meant to connect the proposed concrete batch plant to the UPF building site. The proposed site of the concrete batch plant itself is a highly disturbed fenced area. This area of the project is shown in Fig. 1. The proposed Wet Soils Disposal Area is located on the north side of Bear Creek Road at the former Control Burn Study Area. This is a second growth arce containing thick vegetation, and extensive dead and down woody material. This area of the project is shown in Fig. 2. Thc dry soils storage area is proposed for what is currently known as the West Borrow Area. This site is located on the west side of Reeves Road south of Bear Creek Road. The site is an early successional

  19. Low-Energy Rate Enhancement in Recombination Processes of Electrons into Bare Uranium Ions

    Institute of Scientific and Technical Information of China (English)

    WU Yong; ZENG Si-Liang; DUAN Bin; YAN Jun; WANG Jian-Guo; DONG Chen-Zhong; MA Xin-Wen

    2007-01-01

    Based on the Dirac-Fork-Slater method combined with the multichannel quantum defect theory, the recombination processes of electrons into bare uranium ions (U92+) are investigated in the relative energy range close to zero, and the x-ray spectrum emitted in the direct radiative recombination and cascades processes are simulated. Compared with the recent measurement, it is found that the rate enhancement comes from the additional populations on high Rydberg states. These additional populations may be produced by other recombination mechanisms, such as the external electric-magnetic effects and the many-body correlation effects, which still remains an open problem.

  20. Tetra- and hexavalent uranium forms bidentate-mononuclear complexes with particulate organic matter in a naturally uranium-enriched peatland

    DEFF Research Database (Denmark)

    Mikutta, Christian; Langner, Peggy; Bargar, John R.

    2016-01-01

    of bidentate-mononuclear U(IV/VI) complexes with carboxyl groups. We neither found evidence for U shells at ∼3.9 Å, indicative of mineral-associated U or multinuclear U(IV) species, nor for a substantial P/Fe coordination of U. Our data indicates that U(IV/VI) complexation by natural organic matter prevents...

  1. Development of a Waste Treatment Process to Deactivate Reactive Uranium Metal and Produce a Stable Waste Form

    Energy Technology Data Exchange (ETDEWEB)

    Gates-Anderson, D D; Laue, C A; Fitch, T E

    2002-01-17

    This paper highlights the results of initial investigations conducted to support the development of an integrated treatment process to convert pyrophoric metallic uranium wastes to a non-pyrophoric waste that is acceptable for land disposal. Several dissolution systems were evaluated to determine their suitability to dissolve uranium metal and that yield a final waste form containing uranium specie(s) amenable to precipitation, stabilization, adsorption, or ion exchange. During initial studies, one gram aliquots of uranium metal or the uranium alloy U-2%Mo were treated with 5 to 60 mL of selected reagents. Treatment systems screened included acids, acid mixtures, and bases with and without addition of oxidants. Reagents used included hydrochloric, sulfuric, nitric, and phosphoric acids, sodium hypochlorite, sodium hydroxide and hydrogen peroxide. Complete dissolution of the uranium turnings was achieved with the H{sub 3}PO{sub 4}/HCI system at room temperature within minutes. The sodium hydroxide/hydrogen peroxide, and sodium hypochlorite systems achieved complete dissolution but required elevated temperatures and longer reaction times. A ranking system based on criteria, such as corrosiveness, temperature, dissolution time, off-gas type and amount, and liquid to solid ratio, was designed to determine the treatment systems that should be developed further for a full-scale process. The highest-ranking systems, nitric acid/sulfuric acid and hydrochloric acid/phosphoric acid, were given priority in our follow-on investigations.

  2. Development of industrial-scale fission {sup 99}Mo production process using low enriched uranium target

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Kon; Lee, Jun Sig [Radioisotope Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Beyer, Gerd J. [Grunicke Strasse 15, Leipzig (Germany)

    2016-06-15

    Molybdenum-99 ({sup 99}Mo) is the most important isotope because its daughter isotope, technetium-99m ({sup 99}mTc), has been the most widely used medical radioisotope for more than 50 years, accounting for > 80% of total nuclear diagnostics worldwide. In this review, radiochemical routes for the production of {sup 99}Mo, and the aspects for selecting a suitable process strategy are discussed from the historical viewpoint of {sup 99}Mo technology developments. Most of the industrial-scale {sup 99}Mo processes have been based on the fission of {sup 235}U. Recently, important issues have been raised for the conversion of fission {sup 99}Mo targets from highly enriched uranium to low enriched uranium (LEU). The development of new LEU targets with higher density was requested to compensate for the loss of {sup 99}Mo yield, caused by a significant reduction of {sup 235}U enrichment, from the conversion. As the dramatic increment of intermediate level liquid waste is also expected from the conversion, an effective strategy to reduce the waste generation from the fission {sup 99}Mo production is required. The mitigation of radioxenon emission from medical radioisotope production facilities is discussed in relation with the monitoring of nuclear explosions and comprehensive nuclear test ban. Lastly, the {sup 99}Mo production process paired with the Korea Atomic Energy Research Institute's own LEU target is proposed as one of the most suitable processes for the LEU target.

  3. Radiometric Determination of Uranium in Natural Waters after Enrichment and Separation by Cation-Exchange and Liquid-Liquid Extraction

    CERN Document Server

    Pashalidis, I

    2003-01-01

    The alpha-radiometric determination of uranium after its pre-concentration from natural water samples using the cation-exchange resin Chelex-100, its selective extraction by tributylphosphate and electrodeposition on stainless steel discs is reported. The validity of the separation procedure and the chemical recoveries were checked by addition of uranium standard solution as well as by tracing with U-232. The average uranium yield was determined to be (97 +- 2) % for the cation-exchange, (95 +- 2) % for the liquid-liquid extraction, and more than 99% for the electrodeposition. Employing high-resolution alpha-spectroscopy, the measured activity of the U-238 and U-234 radioisotopes was found to be of similar magnitude; i.e. ~7 mBq/L and ~35 mBq/L for ground- and seawater samples, respectively. The energy resolution (FWHM) of the alpha-peaks was 22 keV, while the Minimum Detectable Activity (MDA) was estimated to be 1 mBq/L (at the 95% confidence limit).

  4. Processing used nuclear fuel with nanoscale control of uranium and ultrafiltration

    Science.gov (United States)

    Wylie, Ernest M.; Peruski, Kathryn M.; Prizio, Sarah E.; Bridges, Andrea N. A.; Rudisill, Tracy S.; Hobbs, David T.; Phillip, William A.; Burns, Peter C.

    2016-05-01

    Current separation and purification technologies utilized in the nuclear fuel cycle rely primarily on liquid-liquid extraction and ion-exchange processes. Here, we report a laboratory-scale aqueous process that demonstrates nanoscale control for the recovery of uranium from simulated used nuclear fuel (SIMFUEL). The selective, hydrogen peroxide induced oxidative dissolution of SIMFUEL material results in the rapid assembly of persistent uranyl peroxide nanocluster species that can be separated and recovered at moderate to high yield from other process-soluble constituents using sequestration-assisted ultrafiltration. Implementation of size-selective physical processes like filtration could results in an overall simplification of nuclear fuel cycle technology, improving the environmental consequences of nuclear energy and reducing costs of processing.

  5. Determination of the isotopic composition of natural and slightly enriched uranium by alpha-spectrometry

    DEFF Research Database (Denmark)

    Kunzendorf, Helmar

    1968-01-01

    Determinations of the isotope contents of 238U, 235U and 234U in five uranium samples containing 0–5 at% 235U were carried out on the basis of a least-squares fit of the α-spectra from the samples, measured with a semiconductor detector, to the theoretically expected α-spectra. With a simple source...

  6. Natural resources and control processes

    CERN Document Server

    Wang, Mu-Hao; Hung, Yung-Tse; Shammas, Nazih

    2016-01-01

    This edited book has been designed to serve as a natural resources engineering reference book as well as a supplemental textbook. This volume is part of the Handbook of Environmental Engineering series, an incredible collection of methodologies that study the effects of pollution and waste in their three basic forms: gas, solid, and liquid. It complements two other books in the series including Environmental and Natural Resources Engineering and Integrated Natural Resources Management that serve as a basis for advanced study or specialized investigation of the theory and analysis of various natural resources systems. This book covers the management of many waste sources including those from agricultural livestock, deep-wells, industries manufacturing dyes, and municipal solid waste incinerators. The purpose of this book is to thoroughly prepare the reader for understanding the sources, treatment and control methods of toxic wastes shown to have harmful effects on the environment. Chapters provide information ...

  7. Uranium: A Dentist's perspective

    OpenAIRE

    Toor, R. S. S.; Brar, G. S.

    2012-01-01

    Uranium is a naturally occurring radionuclide found in granite and other mineral deposits. In its natural state, it consists of three isotopes (U-234, U-235 and U-238). On an average, 1% – 2% of ingested uranium is absorbed in the gastrointestinal tract in adults. The absorbed uranium rapidly enters the bloodstream and forms a diffusible ionic uranyl hydrogen carbonate complex (UO2HCO3+) which is in equilibrium with a nondiffusible uranyl albumin complex. In the skeleton, the uranyl ion repla...

  8. CONCEPTUAL PROCESS DESCRIPTION FOR THE MANUFACTURE OF LOW-ENRICHED URANIUM-MOLYBDENUM FUEL

    Energy Technology Data Exchange (ETDEWEB)

    Daniel M. Wachs; Curtis R. Clark; Randall J. Dunavant

    2008-02-01

    The National Nuclear Security Agency Global Threat Reduction Initiative (GTRI) is tasked with minimizing the use of high-enriched uranium (HEU) worldwide. A key component of that effort is the conversion of research reactors from HEU to low-enriched uranium (LEU) fuels. The GTRI Convert Fuel Development program, previously known as the Reduced Enrichment for Research and Test Reactors program was initiated in 1978 by the United States Department of Energy to develop the nuclear fuels necessary to enable these conversions. The program cooperates with the research reactors’ operators to achieve this goal of HEU to LEU conversion without reduction in reactor performance. The programmatic mandate is to complete the conversion of all civilian domestic research reactors by 2014. These reactors include the five domestic high-performance research reactors (HPRR), namely: the High Flux Isotope Reactor at the Oak Ridge National Laboratory, the Advanced Test Reactor at the Idaho National Laboratory, the National Bureau of Standards Reactor at the National Institute of Standards and Technology, the Missouri University Research Reactor at the University of Missouri–Columbia, and the MIT Reactor-II at the Massachusetts Institute of Technology. Characteristics for each of the HPRRs are given in Appendix A. The GTRI Convert Fuel Development program is currently engaged in the development of a novel nuclear fuel that will enable these conversions. The fuel design is based on a monolithic fuel meat (made from a uranium-molybdenum alloy) clad in Al-6061 that has shown excellent performance in irradiation testing. The unique aspects of the fuel design, however, necessitate the development and implementation of new fabrication techniques and, thus, establishment of the infrastructure to ensure adequate fuel fabrication capability. A conceptual fabrication process description and rough estimates of the total facility throughput are described in this document as a basis for

  9. The neurotoxicology of uranium.

    Science.gov (United States)

    Dinocourt, Céline; Legrand, Marie; Dublineau, Isabelle; Lestaevel, Philippe

    2015-11-01

    The brain is a target of environmental toxic pollutants that impair cerebral functions. Uranium is present in the environment as a result of natural deposits and release by human applications. The first part of this review describes the passage of uranium into the brain, and its effects on neurological functions and cognitive abilities. Very few human studies have looked at its cognitive effects. Experimental studies show that after exposure, uranium can reach the brain and lead to neurobehavioral impairments, including increased locomotor activity, perturbation of the sleep-wake cycle, decreased memory, and increased anxiety. The mechanisms underlying these neurobehavioral disturbances are not clearly understood. It is evident that there must be more than one toxic mechanism and that it might include different targets in the brain. In the second part, we therefore review the principal mechanisms that have been investigated in experimental models: imbalance of the anti/pro-oxidant system and neurochemical and neurophysiological pathways. Uranium effects are clearly specific according to brain area, dose, and time. Nonetheless, this review demonstrates the paucity of data about its effects on developmental processes and the need for more attention to the consequences of exposure during development.

  10. Uranium market as well as production and processing of reactor fuel, 1995/1996; Rynek uranu oraz produkcji i przerobu paliw reaktorowych, 1995/1996

    Energy Technology Data Exchange (ETDEWEB)

    Dembinski, W. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    1997-12-01

    The worldwide uranium market has been analysed in period of 1995/1996. The uranium reserves, production of reactor fuel from natural ores and from fuel recycling have been presented.The worldwide price tendency have been discussed on that background. 3 refs, 1 fig., 3 tabs.

  11. Uranium and thorium behavior in groundwater of the natural spa area “Choygan mineral water” (East Tuva)

    Science.gov (United States)

    Kopylova, Y.; Guseva, N.; Shestakova, A.; Khvaschevskaya, A.; Arakchaa, K.

    2015-11-01

    The natural spa area “Choygan mineral waters”, a unique deposit of natural carbon dioxide mineral waters in Siberia, is located in the Eastern Sayan Mountains. There are 33 spring discharges in this area. Spring waters are mainly of HCO3-Na-Ca type. TDS varies from 300 mg/L to 2600 mg/L, the temperature ranges from 7 °C (in spring 33) to 39 °C (in spring 12), pH varies from 5.9 to 8.3, and the value of the oxidation-reduction potential is from -170 mV to 236 mV. All studied waters were divided into two groups according to their temperature and geochemical conditions: cold fresh water in oxidizing environment and warm slightly brackish water in reducing environment. The uranium concentration varies from 0.7 to 14 μg/l and the thorium concentration varies from 0.001 to 0.33 μg/l in the studied waters. The predominant uranium complexes are (UO2(CO3)3)4-, (UO2(CO3)2)2-, UO2CO3, (UO2(PO4)2)4- in the waters in oxidizing and reducing environments. It was found that acid-alkaline and oxidizing-reducing conditions were the determining factors for uranium behavior and speciation in the studied waters. The pH conditions are determining factors for thorium behavior and speciation in the studied waters. In slightly acidic water the predominant thorium species is negatively charge complex (ThCO3(OH)3)- (more than 95%).

  12. Radiochemical separation of thorium from 18O induced reaction with natural uranium

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A radiochemical procedure used to separate and purify trace concentra tion thorium produced in heavy ion reaction with uranium targets is presented. The procedure can rapidly yield thorium fraction suitable for gamma-ray spectroscopy studies. The resultant gamma-ray spectra showed that Th was isolated from a large number of elements produced in the reaction, and there were only a few contaminat ing activities of isotopes of Sc, Cd, In, etc. The decontamination factors for the main reaction products are given.

  13. Determination of Natural and Depleted Uranium in Urine at the ppt Level: An Interlaboratory Analytical Exercise

    Science.gov (United States)

    2002-10-01

    Q-MS) la spectrom6trie de masse A ionisation thermique (TIMS) et l’analyse par activation neutronique (NAA). Des rrsultats complets ont 6t6 obtenus de...laboratoire h6te. L’analyse par activation neutronique et TIMS enregistraient des concentrations d’uranium total qui diffrraient de celles du laboratoire...Q-MS) la spectromdtrie de masse h ionisation thermique (TIMS) et l’analyse par activation neutronique (NAA). RWsultats: Des ensembles de 12

  14. Manufacturing Process Development to Produce Depleted Uranium Wire for EBAM Feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, David John [Los Alamos National Laboratory; Clarke, Kester Diederik [Los Alamos National Laboratory; Coughlin, Daniel Robert [Los Alamos National Laboratory; Scott, Jeffrey E. [Los Alamos National Laboratory

    2015-06-30

    Wire produced from depleted uranium (DU) is needed as feedstock for the Electron-Beam Additive Manufacturing (EBAM) process. The goal is to produce long lengths of DU wire with round or rectangular cross section, nominally 1.5 mm (0.060 inches). It was found that rolling methods, rather than swaging or drawing, are preferable for production of intermediate quantities of DU wire. Trials with grooveless rolling have shown that it is suitable for initial reductions of large stock. Initial trials with grooved rolling have been successful, for certain materials. Modified square grooves (square round-bottom vee grooves) with 12.5 % reduction of area per pass have been selected for the reduction process.

  15. Natural arsenic and uranium accumulation and remobilization in different geological environments

    OpenAIRE

    Banning, Andre

    2012-01-01

    Despite the fact that both As and U represent geogenic trace elements potentially toxic to humans, little information is available on the development of their enrichments in German sediments and their potential impact on groundwater quality, let alone a systematic overview of the country´s natural occurrences. This work aims at characterizing accumulation processes in aquifers actually or potentially affected by elevated concentrations of As and/or U, and their timings in geological history. ...

  16. CHEMICAL TOXICITY OF URANIUM

    Directory of Open Access Journals (Sweden)

    Sermin Cam

    2007-06-01

    Full Text Available Uranium, occurs naturally in the earth’s crust, is an alpha emitter radioactive element from the actinide group. For this reason, U-235 and U-238, are uranium isotopes with long half lives, have got radiological toxicity. But, for natural-isotopic-composition uranium (NatU, there is greater risk from chemical toxicity than radiological toxicity. When uranium is get into the body with anyway, also its chemical toxicity must be thought. [TAF Prev Med Bull 2007; 6(3.000: 215-220

  17. Distribution of natural radionuclides and uranium activity ratio in Gulf of Thailand sediments as base line data

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, S.K.; Hideki, A. [National Institute of Radiological Sciences (Japan); Kritsananuwat, R.; Fukushi, M. [Tokyo Metropolitan University (Japan); Chanyotha, S.; Pangza, K. [Chulalongkorn University (Thailand)

    2014-07-01

    This paper reports distribution of naturally occurring radionuclides and uranium activity ratio in marine sediments from selected coast, along the Gulf of Thailand to establish baseline data. Thailand has a plan to construct nuclear power plants (NPPs) as well as coal-fired thermal power plants to generate adequate and reliable electricity supply for rapid growth of industrialization. Therefore, it is important to focus not only on security and adequacy of power system but also on environmental protection and monitoring and risk assessment. To carry out environmental monitoring, baseline data plays a significant role. These data should be established and available before set up of mega projects that could impact the environment and health. Therefore, we have collected samples from five areas in the Gulf of Thailand, which are proposed as potential sites, to set up power plants by Thailand government. A total number of fifty-four marine sediment samples were collected. Gamma spectroscopy was used to determine the concentration of natural radionuclides e.g. {sup 226}Ra, {sup 228}Ac and {sup 40}K. Activity concentrations of {sup 226}Ra, {sup 228}Ac and {sup 40}K vary from 2.91-67.17 Bq/kg with an average of 26.64±14.57 Bq/kg, 4.42-109.17 Bq/kg with an average of 43.79±23.92 Bq/kg and 3.36-1004.56 Bq/kg with an average of 393.56±208.04 Bq/kg, respectively. The radiation hazard parameters including absorbed dose rate (D), annual effective dose equivalent (AEDE), radium equivalent activity (AGDE) and external hazard index (Hex) were calculated and compared with the international recommended values. We have noticed that sediments from two sites characterized by similar geological nature of landforms with a rocky coast have higher concentration of natural radionuclides. Concentration of uranium was determined using the inductively coupled plasma mass spectrometry (ICP-MS) and isotopic composition of {sup 234}U/{sup 238}U and {sup 235}U/{sup 238}U were determined using

  18. Microbiological, Geochemical and Hydrologic Processes Controlling Uranium Mobility: An Integrated Field-Scale Subsurface Research Challenge Site at Rifle, Colorado, Quality Assurance Project Plan

    Energy Technology Data Exchange (ETDEWEB)

    Fix, N. J.

    2008-01-07

    The U.S. Department of Energy (DOE) is cleaning up and/or monitoring large, dilute plumes contaminated by metals, such as uranium and chromium, whose mobility and solubility change with redox status. Field-scale experiments with acetate as the electron donor have stimulated metal-reducing bacteria to effectively remove uranium [U(VI)] from groundwater at the Uranium Mill Tailings Site in Rifle, Colorado. The Pacific Northwest National Laboratory and a multidisciplinary team of national laboratory and academic collaborators has embarked on a research proposed for the Rifle site, the object of which is to gain a comprehensive and mechanistic understanding of the microbial factors and associated geochemistry controlling uranium mobility so that DOE can confidently remediate uranium plumes as well as support stewardship of uranium-contaminated sites. This Quality Assurance Project Plan provides the quality assurance requirements and processes that will be followed by the Rifle Integrated Field-Scale Subsurface Research Challenge Project.

  19. Progress in developing processes for converting {sup 99}Mo production from high- to low-enriched uranium--1998.

    Energy Technology Data Exchange (ETDEWEB)

    Conner, C.

    1998-10-28

    During 1998, the emphasis of our activities was focused mainly on target fabrication. Successful conversion requires a reliable irradiation target; the target being developed uses thin foils of uranium metal, which can be removed from the target hardware for dissolution and processing. This paper describes successes in (1) improving our method for heat-treating the uranium foil to produce a random-small grain structure, (2) improving electrodeposition of zinc and nickel fission-fragment barriers onto the foil, and (3) showing that these fission fragment barriers should be stable during transport of the targets following irradiation. A method was also developed for quantitatively electrodepositing uranium and plutonium contaminants in the {sup 99}Mo. Progress was also made in broadening international cooperation in our development activities.

  20. Stochastic Nature in Cellular Processes

    Institute of Scientific and Technical Information of China (English)

    刘波; 刘圣君; 王祺; 晏世伟; 耿轶钊; SAKATA Fumihiko; GAO Xing-Fa

    2011-01-01

    The importance of stochasticity in cellular processes is increasingly recognized in both theoretical and experimental studies. General features of stochasticity in gene regulation and expression are briefly reviewed in this article, which include the main experimental phenomena, classification, quantization and regulation of noises. The correlation and transmission of noise in cascade networks are analyzed further and the stochastic simulation methods that can capture effects of intrinsic and extrinsic noise are described.

  1. Research and Development of Crystal Purification for Product of Uranium Crystallization Process

    Energy Technology Data Exchange (ETDEWEB)

    Yano, K. [Japan Atomic Energy Agency - JAEA (Japan)

    2009-06-15

    Uranium crystallization has been developed as a part of advanced aqueous reprocessing for FBR spent fuel. Although the purity of uranyl nitrate hexahydrate (UNH) crystal from the crystallization process is supposed to meet a specification of FBR blanket fuel, an improvement of its purity is able to reduce the cost of fuel fabrication and storage (in case interim storage of recovered uranium is required). In this work, UNH crystal purification was developed as additional process after crystallization. Contamination of the crystal is caused by mother solution and solid state impurities. They are inseparable by washing and filtration. Mother solution on the surface of UNH crystals is removable by washing, but it is difficult to remove that in an obstructed part of crystalline aggregate by washing. Major elements of solid state impurities are cesium and barium. Cesium precipitates with tetravalent plutonium as a double nitrate, Cs{sub 2}Pu(NO{sub 3}){sub 6}. Barium crystallizes as Ba(NO{sub 3}){sub 2} because of its low solubility in nitric acid solution. It is difficult to separate their particle from UNH crystal by solid-liquid separation such as simple filtration. As a kind of crystal purification, there are some methods using sweating. Sweating is a phenomenon that a crystal melts partly below its melting point and it is caused by depression of freezing point due to impurity. It is considerably applicable for removal of mother solution. Concerning the solid state impurities, which has higher melting point than that of UNH crystal, it is supposed that they are separable by melting UNH crystal and filtration. The behaviors of impurities and applicability of sweating and melting-filtration operations to the purification for UNH crystal were investigated experimentally on a beaker and an engineering scale. With regard to behaviors of impurities, the conditions of cesium and barium precipitation were surveyed and it was clarified that there were most impurities on the

  2. Contribution of analytical techniques coupled to the knowledge of the uranium speciation in natural conditions; Apports des techniques analytiques couplees a la connaissance de la speciation de l'uranium en conditions naturelles

    Energy Technology Data Exchange (ETDEWEB)

    Petit, J.

    2009-06-15

    To understand the transport mechanisms and the radionuclides behaviour in the bio-geosphere is necessary to evaluate healthy and environmental risks of nuclear industry. These mechanisms are monitored by radioelements speciation, namely the distribution between their different physico-chemical forms in the environment. From this perspective, this PhD thesis deals with uranium speciation in a natural background. A detailed summary of uranium biogeochemistry has been written, which enables to restrict the PhD issue to uranium complexation with oxalic acid, a hydrophilic organic acid with good binding properties, ubiquitous in soil waters. Analytical conditions have been established by means of speciation diagrams. The speciation diagrams building by means of literature stability constants has allowed to define the analytical conditions of complex formation. The chosen analytical technique is the hyphenation of a separative technique (liquid chromatography LC or capillary electrophoresis CE) with mass spectrometry (ICPMS). The studied complexes presence in the synthetic samples has been confirmed with UV/visible spectrophotometry. LC-ICPMS analyses have proved the lability of the uranyl-organic acid complexes, namely their tendency to dissociate during analysis, which prevents from studying uranium speciation. CE-ICPMS study of labile complexes from a metal-ligand system has been made possible by employing affinity capillary electrophoresis, which enables to determine stability constants and electrophoretic mobilities. This PhD thesis has allowed to compare the different mathematical treatments of binding isotherm and to take into account ionic strength and real ligand concentration. Affinity CE has been applied successfully to lanthanum-oxalate (model system) and uranium-oxalate systems. The obtained results have been applied to a real system (situated in Le Bouchet). This shows the contribution of the developed method to the modelling of uranium speciation. (author)

  3. Standard test method for uranium analysis in natural and waste water by X-ray fluorescence

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This test method applies for the determination of trace uranium content in waste water. It covers concentrations of U between 0.05 mg/L and 2 mg/L. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  4. Dioxins, furans, biphenyls, arsenic, thorium and uranium in natural and anthropogenic sources of phosphorus and calcium used in agriculture.

    Science.gov (United States)

    Avelar, A C; Ferreira, W M; Pemberthy, D; Abad, E; Amaral, M A

    2016-05-01

    The aim of this study was to assess the presence of dioxins, furans and biphenyls, and the inorganic contaminants such as arsenic (As), thorium (Th) and uranium (U) in three main products used in Agriculture in Brazil: feed grade dicalcium phosphate, calcined bovine bone meal and calcitic limestone. The first two are anthropogenic sources of phosphorus and calcium, while calcitic limestone is a natural unprocessed mineral. Regarding to dioxin-like substances, all samples analyzed exhibited dioxins (PCDD) and furans (PCDF) and dioxin-like polychlorinated biphenyls (dl-PCBs) concentrations below limit of detection (LOD). In general, achieved is in accordance with regulation in Brazil where is established a maximum limit in limestone used in the citric pulp production (0.50pg WHO-TEQ g(-1)). In addition, reported data revealed very low levels for limestone in comparison with similar materials reported by European legislation. As result for toxic metals, achieved data were obtained using Instrumental Neutron Activation Analysis (INAA). On one hand, limestone sample exhibits the largest arsenic concentration. On another hand, dicalcium phosphate exhibited the largest uranium concentration, which represents a standard in animal nutrition. Therefore, it is phosphorus source in the animal feed industry can be a goal of concern in the feed field. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Neutron-induced transmutation reactions in 237Np, 238Pu, and 239Pu at the massive natural uranium spallation target

    Science.gov (United States)

    Zavorka, L.; Adam, J.; Baldin, A. A.; Caloun, P.; Chilap, V. V.; Furman, W. I.; Kadykov, M. G.; Khushvaktov, J.; Pronskikh, V. S.; Solnyshkin, A. A.; Sotnikov, V.; Stegailov, V. I.; Suchopar, M.; Tsoupko-Sitnikov, V. M.; Tyutyunnikov, S. I.; Voronko, V.; Vrzalova, J.

    2015-04-01

    Transmutation reactions in the 237Np, 238Pu, and 239Pu samples were investigated in the neutron field generated inside a massive (m = 512 kg) natural uranium spallation target. The uranium target assembly QUINTA was irradiated with the deuteron beams of kinetic energy 2, 4, and 8 GeV provided by the Nuclotron accelerator at the Joint Institute for Nuclear Research (JINR) in Dubna. The neutron-induced transmutation of the actinide samples was measured off-line by implementing methods of gamma-ray spectrometry with HPGe detectors. Results of measurement are expressed in the form of both the individual reaction rates and average fission transmutation rates. For the purpose of validation of radiation transport programs, the experimental results were compared with simulations of neutron production and distribution performed by the MCNPX 2.7 and MARS15 codes employing the INCL4-ABLA physics models and LAQGSM event generator, respectively. In general, a good agreement between the experimental and calculated reaction rates was found in the whole interval of provided beam energies.

  6. Alpha and gamma spectrometry for natural radioactive nuclides around uranium mines and nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, A.M.; Tome, F.V.; Bejarano, J.D.; Aparicio, A.G. (Universidad de Extremadura, Badajoz (Spain). Dept. de Fisica)

    1992-01-01

    Concentration of uranium and [sup 234]U/[sup 238]U and [sup 235]U/[sup 238]U activity ratios were studied in water samples taken in the neighbourhood of two uranium mines ('El Lobo' and 'El Pedregal', Badajoz, Spain), and around two nuclear power plants and their cooling reservoirs (the Central Nuclear de Almaraz, which is working today, and the Central Nuclear de Valdecaballeros, which is in the construction phase), using alpha spectrometry with semiconductor detectors. The Valdecaballeros data were taken to check for comparison with those of the Central Nuclear de Almaraz and with future values after the start of operation. Measurements were also made of all soluble gamma emitting nuclides using a shielded coaxial high purity germanium detector. The data suggest that the mechanisms responsible for the changes in the concentrations and in the [sup 234]U/[sup 238]U activity ratios in surface waters are principally dilution and leaching. (author).

  7. Assessing potential risks from exposure to natural uranium in well water

    Energy Technology Data Exchange (ETDEWEB)

    Hakonson-Hayes, A.C.; Fresquez, P.R. E-mail: fresquezp@lanl.gov; Whicker, F.W

    2002-07-01

    Over 50% of the wells in the Nambe region of northern New Mexico exceed the US Environmental Protection Agency's recommended drinking water standard of 20 {mu}g l{sup -1} for {sup 238}U; the highest in the area was measured at 1200 {mu}g U l{sup -1}. Uranium uptake was estimated in tomato (Lycopersicon esculentum), squash (Cucurbita pepo), lettuce (Lactuca scarriola), and radish (Raphanus sativus) irrigated with Nambe well water containing <1, 150, 500, and 1200 {mu}g U l{sup -1}. Plant uptake and human dose and toxicity associated with ingestion of water and produce and inhalation of irrigated soil related to gardening activities were evaluated. Uranium concentration in plants increased linearly with increasing U concentration in irrigation water, particularly in lettuce and radish. The estimated total committed effective dose for 70 years of maximum continuous exposure, via the three pathways to well water containing 1200 {mu}g U l{sup -1}, was 0.17 mSv with a corresponding kidney concentration of 0.8 {mu}g U g{sup -1} kidney.

  8. Natural uranium toxicology - evaluation of internal contamination in man; Toxicologie de l'uranium naturel - essai d'evaluation de la contamination interne chez l'homme

    Energy Technology Data Exchange (ETDEWEB)

    Chalabreysse, J. [Commissariat a l' Energie Atomique, Pierrelatte (France). Centre d' Etudes Nucleaires

    1968-07-01

    After reminding the physical and chemical properties of natural uranium which might affect its toxicology, a comprehensive investigation upon natural uranium metabolism and toxicity and after applying occupational exposure standards to this particular poison, it has been determined, from accident reports and human experience reported in the related literature, a series of formulae obtained by theoretical mathematical development giving principles for internal contamination monitoring and disclosure by determining uranium in the urine of occupationally exposed individuals. An assay is performed to determine individual internal contamination according to the various contamination cases. The outlined purposes, mainly practical, required some options and extrapolations. The proposed formula allows a preliminary approach and also to determine shortly a contamination extent or to discuss the systematical urinalysis results as compared with individual radio-toxicology monitoring professional standards. (author) [French] Apres le rappel des caracteristiques physiques et des proprietes chimiques de l'uranium naturel pouvant avoir une influence sur sa toxicologie, l'etude detaillee de son metabolisme et de sa toxicite, puis l'application des normes professionnelles d'exposition au cas particulier de ce toxique, il est etabli, a partir des comptes rendus d'accidents et de l'experimentation humaine rapportes dans la litterature, une serie de formules obtenues par developpement mathematique theorique qui posent les principes de la surveillance et de la mise en evidence de la contamination interne par la recherche et le dosage de l'uranium dans les urines d'individus professionnellement exposes. Un essai d'evaluation de la contamination interne individuelle suivant les differents cas de contamination est effectue. Le formulaire propose permet de faire une premiere approximation et d'apprecier rapidement l'importance d

  9. Exergetic analysis of human & natural processes

    CERN Document Server

    Banhatti, Dilip G

    2011-01-01

    Using the concept of available work or exergy, each human and natural process can be characterized by its contextual efficiency, that is, efficiency with the environment as a reference. Such an efficiency is termed exergy efficiency. Parts of the process which need to be made more efficient & less wasteful stand out in such an analysis, in contrast to an energy analysis. Any new idea for a process can be similarly characterized. This exercise naturally generates paths to newer ideas in given contexts to maximize exergy efficiency. The contextual efficiency is not just output/input, it also naturally includes environmental impact (to be minimized) and any other relevant parameter(s) to be optimized. Natural life processes in different terrestrial environments are already optimized for their environments, and act as guides, for example, in seeking to evolve sustainable energy practices in different contexts. Energy use at lowest possible temperature for each situation is a natural result. Variety of renewab...

  10. Disposal of residue from uranium ore processing in France; Les stockages de residus de traitement de minerais d'uranium en France

    Energy Technology Data Exchange (ETDEWEB)

    Crochon, Ph. [AREVA NC, Business Group Mines, Dir. de la responsabilite environnementale et societale, 75 -Paris (France)

    2011-02-15

    Between 1949 and 2001, French mines produced 76, 000 metric tons of uranium and 50 million metric tons of ore, processing residues are stored at 17 sites (in ponds enclosed by dykes or in former open-cast mines) subject to ICPE (classified facility for environment protection) regulation. These disposal sites cover surface areas of between one and several tens of hectares and several thousands to several millions of metric tons of waste are stored at them. When uranium mining stopped in France, these sites were redeveloped, with caps placed over the residue to provide mechanical and radiological protection. All these sites are still monitored by AREVA. In the last fifteen years, these sites have been the subject of a number of studies, especially regarding the long-term evolution and impact of the residue. These studies are now being pursued within the framework of the national plan for the management of nuclear materials and waste (PNGMDR). A regulatory and institutional framework regarding long-term management of these disposal sites needs to be defined. (author)

  11. Environmental assessment of remedial action at the Naturita uranium processing site near Naturita, Colorado. Revision 3

    Energy Technology Data Exchange (ETDEWEB)

    1994-02-01

    The proposed remedial action for the Naturita processing site is relocation of the contaminated materials and debris to the Dry Flats disposal site, 6 road miles (mi) [10 kilometers (km)] to the southeast. At the disposal site, the contaminated materials would be stabilized and covered with layers of earth and rock. The proposed disposal site is on land administered by the Bureau of Land Management (BLM) and used primarily for livestock grazing. The final disposal site would cover approximately 57 ac (23 ha), which would be permanently transferred from the BLM to the DOE and restricted from future uses. The remedial action activities would be conducted by the DOE`s Uranium Mill Tailings Remedial Action (UMTRA) Project. The proposed remedial action would result in the loss of approximately 162 ac (66 ha) of soils at the processing and disposal sites; however, 133 ac (55 ha) of these soils at and adjacent to the processing site are contaminated and cannot be used for other purposes. If supplemental standards are approved by the NRC and state of Colorado, approximately 112 ac (45 ha) of contaminated soils adjacent to the processing site would not be cleaned up. This area is steeply sloped. The cleanup of this contamination would have adverse environmental consequences and would be potentially hazardous to remedial action workers. Another 220 ac (89 ha) of soils would be temporarily disturbed during the remedial action. The final disposal site would result in approximately 57 ac (23 ha) being removed from livestock grazing and wildlife use.

  12. Environmental assessment of remedial action at the Naturita Uranium processing site near Naturita, Colorado. Revision 2

    Energy Technology Data Exchange (ETDEWEB)

    1994-01-01

    The proposed remedial action for the Naturita processing site is relocation of the contaminated materials and debris to the Dry Flats disposal sits, 6 road miles (mi) [10 kilometers (km)) to the southeast. At the disposal site, the contaminated materials would be stabilized and covered with layers of earth and rock. The proposed disposal site is on land administered by the Bureau of Land Management (BLM) and used primarily for livestock grazing. The final disposal sits would cover approximately 57 ac (23 ha), which would be permanently transferred from the BLM to the DOE and restricted from future uses. The remedial action activities would be conducted by the DOE`s Uranium Mill Tailings Remedial Action (UMTRA) Project. The proposed remedial action would result in the loss of approximately 162 ac (66 ha) of soils at the processing and disposal sites; however, 133 ac (55 ha) of these soils at and adjacent to the processing site are contaminated and cannot be used for other purposes. If supplemental standards are approved by the NRC and state of Colorado, approximately 112 ac (45 ha) of contaminated soils adjacent to the processing site would not be cleaned up. This area is steeply sloped. The cleanup of this contamination would have adverse environmental consequences and would be potentially hazardous to remedial action workers. Another 220 ac (89 ha) of soils would be temporarily disturbed during the remedial action. The final disposal site would result in approximately 57 ac (23 ha) being removed from livestock grazing and wildlife use.

  13. Design of a uranium-dioxide powder spheroidization system by plasma processing

    Science.gov (United States)

    Cavender, Daniel

    The plasma spheroidization system (PSS) is the first process in the development of a tungsten-uranium dioxide (W-UO2) ceramic-metallic (cermet) fuel for nuclear thermal rocket (NTR) propulsion. For the purposes of fissile fuel retention, UO2 spheroids ranging in size from 50 - 100 micrometers (μm) in diameter will be encapsulated in a tungsten shell. The PSS produces spherical particles by melting angular stock particles in an argon-hydrogen plasma jet where they become spherical due to surface tension. Surrogate CeO 2 powder was used in place of UO2 for system and process parameter development. Stock and spheroidized powders were micrographed using optical and scanning electron microscopy and evaluated by statistical methods to characterize and compare the spherocity of pre and post process powders. Particle spherocity was determined by irregularity parameter. Processed powders showed a statistically significant improvement in spherocity, with greater that 60% of the examined particles having an irregularity parameter of equal to or lower than 1.2, compared to stock powder.

  14. Comparative study on the impact of coal and uranium mining, processing, and transportation in the western United States

    Energy Technology Data Exchange (ETDEWEB)

    Sandquist, G.M.

    1979-06-01

    A comparative study and quantitative assessment of the impacts, costs and benefits associated with the mining, processing and transportation of coal and uranium within the western states, specifically Arizona, California, Colorado, Montana, New Mexico, Oregon, Utah, Washington and Wyoming are presented. The western states possess 49% of the US reserve coal base, 67% of the total identified reserves and 82% of the hypothetical reserves. Western coal production has increased at an average annual rate of about 22% since 1970 and should become the major US coal supplier in the 1980's. The Colorado Plateau (in Arizona, Colorado, New Mexico and Utah) and the Wyoming Basin areas account for 72% of the $15/lb U/sub 3/O/sub 8/ resources, 76% of the $30/lb, and 75% of the $50/lb resources. It is apparent that the West will serve as the major supplier of domestic US coal and uranium fuels for at least the next several decades. Impacts considered are: environmental impacts, (land, water, air quality); health effects of coal and uranium mining, processing, and transportation; risks from transportation accidents; radiological impact of coal and uranium mining; social and economic impacts; and aesthetic impacts (land, air, noise, water, biota, and man-made objects). Economic benefits are discussed.

  15. Measurement methods and optimization of radiation protection: the case of internal exposure by inhalation to natural uranium compounds; Methodes de mesure et optimisation de la radioprotection: le cas des expositions internes par inhalation aux composes d'uranium naturel

    Energy Technology Data Exchange (ETDEWEB)

    Degrange, J.P. [Centre d' Etudes sur l' Evaluation de la Protection dans le domaine Nucleaire (CEPN), 92 - Fontenay-aux-Roses (France); Gibert, B. [Societe pour la Conversion de l' Uranium en Metal et Hexafluorure (COMURHEX), 11 - Narbonne (France)

    1998-07-01

    The aim of this presentation is to discuss the ability of different measurement methods (air sampling and biological examinations) to answer to demands in the particular case of internal exposure by inhalation to natural uranium compounds. The realism and the sensitivity of each method are studied, on the base of new dosimetric models of the ICRP. The ability of analysis of these methods in order to optimize radiation protection are then discussed. (N.C.)

  16. TECHNICAL REPORT ON TECHNOLOGICALLY ENHANCED NATURALLY OCCURRING RADIOACTIVE MATERIALS FROM URANIUM MINING, VOLUME II: INVESTIGATION OF POTENTIAL HEALTH, GEOGRAPHIC, AND ENVIRONMENTAL ISSUES OF ABANDONED URANIUM MINES

    Science.gov (United States)

    Volume II investigates the potential radiogenic risks from abandoned uranium mines and evaluates which may pose the greatest hazards to members of the public and to the environment. The intent of this report is to identify who may be most likely to be exposed to wastes at small a...

  17. Innovative Elution Processes for Recovering Uranium and Transition Metals from Amidoxime-based Adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Wai, Chien M. [Univ. of Idaho, Moscow, ID (United States). Dept. of Chemistry

    2017-04-18

    Amidoxime-based polymer fibers are considered one of the most promising materials for sequestering uranium from seawater. The high-surface-area polymer fibers containing amidoxime and carboxylate groups synthesized by Oak Ridge National Lab (ORNL-AF1) show very high uranium adsorption capacities known in the literature. Effective elution of uranium and repeated use of the adsorbent are important factors affecting the cost of producing uranium from seawater using this material. Traditional acid leaching of uranium followed by KOH conditioning of the fiber causes chemical changes and physical damage to the ORNL-AF1 adsorbent. Two alkaline solution leaching methods were developed by this project, one uses a highly concentrated (3 M) potassium bicarbonate solution at pH 8.3 and 40 °C; the other uses a mixture of sodium carbonate and hydrogen peroxide at pH 10.4. Both elution methods do not require KOH conditioning prior to reusing the fiber adsorbent. The conditions of eluting uranium from the amidoxime-based adsorbent using these alkaline solutions are confirmed by thermodynamic calculations. The bicarbonate elution method is selective for uranium recovery compared to other elution methods and causes no chemical change to the fiber material based on FTIR spectroscopy

  18. The nature of arsenic in uranium mill tailings by X-ray absorption spectroscopy

    Science.gov (United States)

    Cutler, J. N.; Chen, N.; Jiang, D. T.; Demopoulos, G. P.; Jia, Y.; Rowson, J. W.

    2003-05-01

    In order to understand the evolving world of environmental issues, the ability to characterize and predict the stability and bioavailability of heavy métal contaminants in mine waste is becoming increasingly more important. X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopies were used to characterize a series of synthetic and natural samples associated with mine tailings processing. XANES was shown to be excellent as a tool to rapidly differentiate oxidation states of arsenic within the samples. The EXAFS spectra provided information on the mineralogy of the precipitated raffinate and tailings and showed that these samples are composed of a mixture of amorphous ferric arsenates, adsorbed arsenates and a mixture of other poorly ordered arsenates.

  19. Pyrite Oxidation in Leaching Process of Radionuclides and Heavy Metals from Uranium Mill Tailings

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Pyrite is a sensitive mineral in the geological environment, and its oxidation produces an important geochemical and environmental effect on the control of the redox and pH conditions. Column experiment results were used for modeling the geochemical processes in uranium mill tailings under lcaching conditions. Oxidation of pyrite dominates the control of the tailings leaching process. The experimental and modeling results show that the leachate chemistry changes substantially with the decrease in pyrite consumption. In the initial stage of the leaching experiment, the pyrite is consumed several hundred times greater than that in the later stages, for much more oxygen is present in the tailings in the initial stage. As the experiment continues, the tailings is gradually saturated with water and the oxygen concentration greatly decreases and so does pyrite consumption. The experimental and modeling results are useful for the design of mill tailing decommissioning., oxidation process and transport of radioactive nuclides and heavy metals can be constrained by controlling the oxygen concentration of tailings and the infiltration of meteoric water.

  20. The encounter and analysis of naturally occurring radionuclides in gas and oil production and processing

    Energy Technology Data Exchange (ETDEWEB)

    Hartog, F.A.; Jonkers, G.; Knaepen, W.A.I. [Shell Research and Technology Centre, Amsterdam, (Netherlands)

    1996-12-31

    As a result of oil and gas production, radioactive daughter elements from the uranium and thorium decay series can be mobilized and transported away from the reservoir. Due to changes in flow regime, temperature, pressure or chemical environment NORs (Naturally Occurring Radionuclides) may build up in products, by-products or waste streams from gas and oil production and processing facilities. Products containing NORs are commonly denoted by the acronym NORM (Naturally Occurring Radioactive Materials). Main topics of this paper are: E and P (Exploration and Production) NORM characteristics; incentives for NORM analysis; NORM analysis; interlaboratory test programme; analysis techniques; results and conclusions of the test programme. 4 figs., 2 tabs.

  1. Natural Colorants: Historical, Processing and Sustainable Prospects.

    Science.gov (United States)

    Yusuf, Mohd; Shabbir, Mohd; Mohammad, Faqeer

    2017-02-01

    With the public's mature demand in recent times pressurized the textile industry for use of natural colorants, without any harmful effects on environment and aquatic ecosystem, and with more developed functionalities simultaneously. Advanced developments for the natural bio-resources and their sustainable use for multifunctional clothing are gaining pace now. Present review highlights historical overview of natural colorants, classification and predominantly processing of colorants from sources, application on textiles surfaces with the functionalities provided by them. Chemistry of natural colorants on textiles also discussed with relevance to adsorption isotherms and kinetic models for dyeing of textiles.

  2. The mechanical response of a uranium-nobium alloy: a comparison of cast versus wrought processing

    Energy Technology Data Exchange (ETDEWEB)

    Cady, Carl M [Los Alamos National Laboratory; Gray, George T., III [Los Alamos National Laboratory; Cerreta, Ellen K [Los Alamos National Laboratory; Aikin, Robert M [Los Alamos National Laboratory; Chen, Shuh - Rong [Los Alamos National Laboratory; Trujillo, Carl P [Los Alamos National Laboratory; Lopez, Mike F [Los Alamos National Laboratory; Korzekwa, Deniece R [Los Alamos National Laboratory; Kelly, Ann M [Los Alamos National Laboratory

    2009-02-13

    A rigorous experimentation and validation program is being undertaken to create constitutive models that elucidate the fundamental mechanisms controlling plasticity in uranium-6 wt.% niobium alloys (U-6Nb). The first, 'wrought', material produced by processing a cast ingot I'ia forging and forming into plate was studied. The second material investigated is a direct cast U-6Nb alloy. The purpose of the investigation is to detennine the principal differences, or more importantly, similarities, between the two materials due to processing. It is well known that parameters like grain size, impurity size and chemistry affect the deformation and failure characteristics of materials. Metallography conducted on these materials revealed that the microstructures are quite different. Characterization techniques like tension, compression, and shear were performed to find the principal differences between the materials as a function of stress state. Dynamic characterization using a split Hopkinson pressure bar in conjunction with Taylor impact testing was conducted to derive and thereafter validate constitutive material models. The Mechanical Threshold Strength Model is shown to accurately capture the constitutive response of these materials and Taylor cylinder tests are used to provide a robust way to verify and validate the constitutive model predictions of deformation by comparing finite element simulations with the experimental results. The primary differences between the materials will be described and predictions about material behavior will be made.

  3. Ancient natural uranium oxide as analog of spent fuel: Contribution to assessing the impact of helium production on long term evolution of UO{sub 2} matrix

    Energy Technology Data Exchange (ETDEWEB)

    Roudil, D.; Folch, B.; Jegou, C. [CEA centre de Marcoule BP 17171 30207 Bagnols sur Ceze cedex (France); Pik, R. [CNRS CRPG- 54506 Vandoeuvre les Nancy (France); Cuney, M. [Nancy Universite, G2R, CNRS, CREGU, BP 239, 54506, Vandoeuvre les Nancy (France); Gauthier-Lafaye, F. [ULP-EOST-CNRS/CGS- 1, rue Blessig - 67084 Strasbourg (France)

    2008-07-01

    Nuclear waste management in particular for spent fuel disposal option, needs an improvement of the knowledge concerning the fate of helium produced by actinide decrease and its impact on the physical and structural changes on the fuel matrix in a repository. An original alternative to {alpha} ageing simulation concerns the study and characterization of different old natural uranium oxides, with increasing age of crystallization. Since 2005, in the framework of a collaboration between Cea DEN/DTCD, CREGU and CNRS a methodology devoted to the study of helium behavior in this kind of samples has been developed and applied to three natural uranium oxides. Coupling results from gas release mass spectrometry measurements and from HR-TEM showed: -) high helium mobility at low temperature, -) an helium retention always lower than 0,9 at% in the uranium oxide grains, and -) high concentration of nanometer size helium bubbles, poorly pressurized and released at high temperature (above 1300 deg. C). Predictable evolutions of spent fuel matrix under self irradiation are presented within the domain of physical, chemical and structural analogy between natural uranium oxides and spent fuels. (authors)

  4. Anomalous one-electron processes in the chemistry of uranium nitrogen multiple bonds.

    Science.gov (United States)

    Mullane, Kimberly C; Lewis, Andrew J; Yin, Haolin; Carroll, Patrick J; Schelter, Eric J

    2014-09-02

    Novel reaction pathways are illustrated in the synthesis of uranium(IV), uranium(V), and uranium(VI) monoimido complexes. In contrast to the straightforward preparation of U(V)(═NSiMe3)[N(SiMe3)2]3 (1), the synthesis of a uranium(V) tritylimido complex, U(V)(═NCPh3)[N(SiMe3)2]3 (4), from U(III)[N(SiMe3)2]3 and Ph3CN3 was found to proceed through multiple one-electron steps. Whereas the oxidation of 1 with copper(II) salts produced the uranium(VI) monoimido complexes U(VI)(═NSiMe3)X[N(SiMe3)2]3 (X = Cl, Br), the reaction of 4 with CuBr2 undergoes sterically induced reduction to form the uranium(VI) monoimido complex U(VI)(═NCPh3)Br2[N(SiMe3)2]2, demonstrating a striking difference in reactivity based on imido substituent. The facile reduction of compounds 1 and 4 with KC8 allowed for the synthesis of the uranium(IV) monoimido derivatives, K[U(IV)(═NSiMe3)[N(SiMe3)2]3] (1-K) and K[U(IV)(═NCPh3)[N(SiMe3)2]3] (4-K), respectively. In contrast, an analogous uranium(IV) monoimido complex, K[U(IV)(═NPh(F))[N(SiMe3)Ph(F)

  5. Dioxins, furans, biphenyls, arsenic, thorium and uranium in natural and anthropogenic sources of phosphorus and calcium used in agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Avelar, A.C., E-mail: avelara@ufmg.br [Department of Animal Sciences, Veterinary School, Universidad de Federal de Minas Gerais Avenida Antonio Carlos, 6627 Campus UFMG, Belo Horizonte (Brazil); Ferreira, W.M. [Department of Animal Sciences, Veterinary School, Universidad de Federal de Minas Gerais Avenida Antonio Carlos, 6627 Campus UFMG, Belo Horizonte (Brazil); Pemberthy, D. [Spanish Council for Scientific Research (CSIC), Institute of Environmental Assessment and Water Research, C/ Jordi Girona 18-26, 08034 Barcelona (Spain); Universidad de Antioquia, Departamento de Ingeniería Química, Facultad de Ingeniería, Grupo Catálisis Ambiental, Calle 70 No. 52-2, Medellín (Colombia); Abad, E. [Spanish Council for Scientific Research (CSIC), Institute of Environmental Assessment and Water Research, C/ Jordi Girona 18-26, 08034 Barcelona (Spain); Amaral, M.A. [Department of Animal Sciences, Veterinary School, Universidad de Federal de Minas Gerais Avenida Antonio Carlos, 6627 Campus UFMG, Belo Horizonte (Brazil)

    2016-05-01

    The aim of this study was to assess the presence of dioxins, furans and biphenyls, and the inorganic contaminants such as arsenic (As), thorium (Th) and uranium (U) in three main products used in Agriculture in Brazil: feed grade dicalcium phosphate, calcined bovine bone meal and calcitic limestone. The first two are anthropogenic sources of phosphorus and calcium, while calcitic limestone is a natural unprocessed mineral. Regarding to dioxin-like substances, all samples analyzed exhibited dioxins (PCDD) and furans (PCDF) and dioxin-like polychlorinated biphenyls (dl-PCBs) concentrations below limit of detection (LOD). In general, achieved is in accordance with regulation in Brazil where is established a maximum limit in limestone used in the citric pulp production (0.50 pg WHO-TEQ g{sup −1}). In addition, reported data revealed very low levels for limestone in comparison with similar materials reported by European legislation. As result for toxic metals, achieved data were obtained using Instrumental Neutron Activation Analysis (INAA). On one hand, limestone sample exhibits the largest arsenic concentration. On another hand, dicalcium phosphate exhibited the largest uranium concentration, which represents a standard in animal nutrition. Therefore, it is phosphorus source in the animal feed industry can be a goal of concern in the feed field. - Highlights: • PCDD/Fs dl- PCBs is not a matter since levels below the LOD in phosphate materials subject of study. • Significant accumulation of As and U in Limestone. Th was originally found in dicalcium phosphate. • High concentration of U in dicalcium phosphate suggests that a special attention should be paid.

  6. Uranium in groundwater--Fertilizers versus geogenic sources.

    Science.gov (United States)

    Liesch, Tanja; Hinrichsen, Sören; Goldscheider, Nico

    2015-12-01

    Due to its radiological and toxicological properties even at low concentration levels, uranium is increasingly recognized as relevant contaminant in drinking water from aquifers. Uranium originates from different sources, including natural or geogenic, mining and industrial activities, and fertilizers in agriculture. The goal of this study was to obtain insights into the origin of uranium in groundwater while differentiating between geogenic sources and fertilizers. A literature review concerning the sources and geochemical processes affecting the occurrence and distribution of uranium in the lithosphere, pedosphere and hydrosphere provided the background for the evaluation of data on uranium in groundwater at regional scale. The state of Baden-Württemberg, Germany, was selected for this study, because of its hydrogeological and land-use diversity, and for reasons of data availability. Uranium and other parameters from N=1935 groundwater monitoring sites were analyzed statistically and geospatially. Results show that (i) 1.6% of all water samples exceed the German legal limit for drinking water (10 μg/L); (ii) The range and spatial distribution of uranium and occasional peak values seem to be related to geogenic sources; (iii) There is a clear relation between agricultural land-use and low-level uranium concentrations, indicating that fertilizers generate a measurable but low background of uranium in groundwater.

  7. India's Worsening Uranium Shortage

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, Michael M.

    2007-01-15

    As a result of NSG restrictions, India cannot import the natural uranium required to fuel its Pressurized Heavy Water Reactors (PHWRs); consequently, it is forced to rely on the expediency of domestic uranium production. However, domestic production from mines and byproduct sources has not kept pace with demand from commercial reactors. This shortage has been officially confirmed by the Indian Planning Commission’s Mid-Term Appraisal of the country’s current Five Year Plan. The report stresses that as a result of the uranium shortage, Indian PHWR load factors have been continually decreasing. The Uranium Corporation of India Ltd (UCIL) operates a number of underground mines in the Singhbhum Shear Zone of Jharkhand, and it is all processed at a single mill in Jaduguda. UCIL is attempting to aggrandize operations by establishing new mines and mills in other states, but the requisite permit-gathering and development time will defer production until at least 2009. A significant portion of India’s uranium comes from byproduct sources, but a number of these are derived from accumulated stores that are nearing exhaustion. A current maximum estimate of indigenous uranium production is 430t/yr (230t from mines and 200t from byproduct sources); whereas, the current uranium requirement for Indian PHWRs is 455t/yr (depending on plant capacity factor). This deficit is exacerbated by the additional requirements of the Indian weapons program. Present power generation capacity of Indian nuclear plants is 4350 MWe. The power generation target set by the Indian Department of Atomic Energy (DAE) is 20,000 MWe by the year 2020. It is expected that around half of this total will be provided by PHWRs using indigenously supplied uranium with the bulk of the remainder provided by breeder reactors or pressurized water reactors using imported low-enriched uranium.

  8. PRODUCTION OF URANIUM

    Science.gov (United States)

    Ruehle, A.E.; Stevenson, J.W.

    1957-11-12

    An improved process is described for the magnesium reduction of UF/sub 4/ to produce uranium metal. In the past, there have been undesirable premature reactions between the Mg and the bomb liner or the UF/sub 4/ before the actual ignition of the bomb reaction. Since these premature reactions impair the yield of uranium metal, they have been inhibited by forming a protective film upon the particles of Mg by reacting it with hydrated uranium tetrafluoride, sodium bifluoride, uranyl fluoride, or uranium trioxide. This may be accomplished by adding about 0.5 to 2% of the additive to the bomb charge.

  9. Geochemistry of uranium and thorium and natural radioactivity levels of the western Anatolian plutons, Turkey

    Science.gov (United States)

    Papadopoulos, Argyrios; Altunkaynak, Şafak; Koroneos, Antonios; Ünal, Alp; Kamaci, Ömer

    2017-01-01

    Seventy samples from major plutons (mainly granitic) of Western Anatolia (Turkey) have been analyzed by γ-ray spectrometry to determine the specific activities of 238U, 226Ra, 232Th and 40K (Bq/kg). Τhe natural radioactivity ranged up to 264 Bq/kg for 238U, 229.62 Bq/kg for 226Ra, up to 207.32 Bq/kg for 232Th and up to 2541.95 Bq/kg for 40K. Any possible relationship between the specific activities of 226Ra, 238U, 232Th and 40K and some characteristics of the studied samples (age, rock-type, colour, grain size, occurrence, chemical and mineralogical composition) was investigated. Age, major and trace element geochemistry, color, pluton location and mineralogical composition are likely to affect the concentrations of the measured radionuclides. The range of the Th/U ratio was large (0.003-11.374). The latter, along with 226Ra/238U radioactive secular disequilibrium, is also discussed and explained by magmatic processes during differentiation.

  10. Processes at interfaces: the effect of carbonate on the dissolution of iron and uranium oxides

    Energy Technology Data Exchange (ETDEWEB)

    Grive, M.; Duro, L.; Bruno, J. [Enviros Spain, Pg. Rubi, 29-31, 08197- Valldoreix, Barcelona (Spain); Pablo, J. de [DEQ Universitat Politecnica de Catalunya, 08028-Barcelona (Spain)

    2005-07-01

    Full text of publication follows: Iron oxides and hydroxides can strongly affect the mobility of radionuclides and, in particular of uranium in oxic groundwaters. The iron cycle is one of the most dynamic systems in the geosphere. Precipitation and dissolution of iron(III) oxy-hydroxides is normally a fast process, and transformations of the ferric phases can lead to immobilisation-mobilization of the trace components associated to these solid phases. Therefore, the understanding of the effect of the different parameters affecting the dynamics of the iron(III) system is paramount to address the migration of the trace components affected by this system. One of the parameters that importantly affects the behaviour of iron(III) solids is carbonate. This ligand, besides forming strong complexes with some radionuclides such as uranium, also forms stable aqueous species with Fe(III). Although the uranium-carbonate complexation has been extensively studied, and the stability of the different species formed is well established, the speciation of Fe(III) in the presence of carbonate is not sufficiently well understood and, therefore, its effect on the mobilization of associated radionuclides is neither sufficiently well addressed. The work presented is focused on the understanding of the effect of carbonate in the solubility and kinetics of dissolution of iron(III) oxides. The results of laboratory experiments on the effect of carbonate on the solubility and kinetics of dissolution of ferri-hydrite and hematite are presented. From the interpretation of the experimental data, the following conclusions have been drawn: 1.- The solubility of ferri-hydrite and hematite is enhanced in the presence of CO{sub 2} mainly due to the formation of two different aqueous complexes, FeOHCO{sub 3} (aq) and Fe(CO{sub 3}){sub 3}{sup 3-} with the following stability constants: Fe{sup 3+} + yH{sub 2}O + zCO{sub 3}{sup 2-} {r_reversible} Fe(OH){sub y}(CO{sub 3}){sub z}{sup 3-y-2z} + y

  11. Processing of solid solution, mixed uranium/refractory metal carbides for advanced space nuclear power and propulsion systems

    Science.gov (United States)

    Knight, Travis Warren

    Nuclear thermal propulsion (NTP) and space nuclear power are two enabling technologies for the manned exploration of space and the development of research outposts in space and on other planets such as Mars. Advanced carbide nuclear fuels have been proposed for application in space nuclear power and propulsion systems. This study examined the processing technologies and optimal parameters necessary to fabricate samples of single phase, solid solution, mixed uranium/refractory metal carbides. In particular, the pseudo-ternary carbide, UC-ZrC-NbC, system was examined with uranium metal mole fractions of 5% and 10% and corresponding uranium densities of 0.8 to 1.8 gU/cc. Efforts were directed to those methods that could produce simple geometry fuel elements or wafers such as those used to fabricate a Square Lattice Honeycomb (SLHC) fuel element and reactor core. Methods of cold uniaxial pressing, sintering by induction heating, and hot pressing by self-resistance heating were investigated. Solid solution, high density (low porosity) samples greater than 95% TD were processed by cold pressing at 150 MPa and sintering above 2600 K for times longer than 90 min. Some impurity oxide phases were noted in some samples attributed to residual gases in the furnace during processing. Also, some samples noted secondary phases of carbon and UC2 due to some hyperstoichiometric powder mixtures having carbon-to-metal ratios greater than one. In all, 33 mixed carbide samples were processed and analyzed with half bearing uranium as ternary carbides of UC-ZrC-NbC. Scanning electron microscopy, x-ray diffraction, and density measurements were used to characterize samples. Samples were processed from powders of the refractory mono-carbides and UC/UC 2 or from powders of uranium hydride (UH3), graphite, and refractory metal carbides to produce hypostoichiometric mixed carbides. Samples processed from the constituent carbide powders and sintered at temperatures above the melting point of UC

  12. Uranium in groundwater — Fertilizers versus geogenic sources

    Energy Technology Data Exchange (ETDEWEB)

    Liesch, Tanja, E-mail: tanja.liesch@kit.edu; Hinrichsen, Sören; Goldscheider, Nico

    2015-12-01

    Due to its radiological and toxicological properties even at low concentration levels, uranium is increasingly recognized as relevant contaminant in drinking water from aquifers. Uranium originates from different sources, including natural or geogenic, mining and industrial activities, and fertilizers in agriculture. The goal of this study was to obtain insights into the origin of uranium in groundwater while differentiating between geogenic sources and fertilizers. A literature review concerning the sources and geochemical processes affecting the occurrence and distribution of uranium in the lithosphere, pedosphere and hydrosphere provided the background for the evaluation of data on uranium in groundwater at regional scale. The state of Baden-Württemberg, Germany, was selected for this study, because of its hydrogeological and land-use diversity, and for reasons of data availability. Uranium and other parameters from N = 1935 groundwater monitoring sites were analyzed statistically and geospatially. Results show that (i) 1.6% of all water samples exceed the German legal limit for drinking water (10 μg/L); (ii) The range and spatial distribution of uranium and occasional peak values seem to be related to geogenic sources; (iii) There is a clear relation between agricultural land-use and low-level uranium concentrations, indicating that fertilizers generate a measurable but low background of uranium in groundwater. - Highlights: • Uranium concentrations in groundwater in Southwest Germany mainly depend on geology. • Only 1.6% of 1935 samples exceed the German legal limit for drinking water of 10 μg/L. • The percentage of positive uranium detections (> 0.5 μg/L) is higher in agricultural areas. • Phosphate fertilizers cause significant increase of uranium in groundwater at low concentration levels.

  13. Natural attenuation reactions at a uranium mill tailings site, western U.S.A.

    Science.gov (United States)

    Zhu, Chen; Anderson, Greg M; Burden, David S

    2002-01-01

    This paper presents a modeling analysis of the geochemical evolution of a contaminated sandy aquifer at a uranium mill tailings site in the western United States. The tailings pond contains fluids having a pH of 1.5 to 3.5 and high levels of As, Be, Cd, Cr, Pb, Mo, Ni, Se, 226Ra, 228Ra, 230Th, 238U, and 234U. Seepage of tailings fluids into the aquifer has formed a low-pH ground water plume. The reclamation plan is to install a low-permeability cover on the tailings pond to stop the seepage and allow the plume to be attenuated by reactions with the aquifer matrix and flushed by uncontaminated upgradient ground water. To evaluate this reclamation scenario, ground water and sediment core samples were analyzed along one flowpath. Speciation-solubility and mass-transfer modeling revealed two sets of chemical reactions for acid seepage and flushing, respectively. The current concentrations and distribution of ground water constituents can be interpreted as being controlled by stepwise pH-buffer reactions with calcite, amorphous aluminum hydroxide, and amorphous iron hydroxides. These buffer reactions divide the aquifer into zones of near-constant pH, separated by interface zones. For the flushing stage, it is predicted that reactions with surface-bound species will dominate the reaction paths, and more pore volumes are required to neutralize the plume than predicted by models that do not consider surface reactions. Direct mineralogical and surface analysis is needed to substantiate this assertion.

  14. Assessment of the vertical distribution of natural radionuclides in a mineralized uranium area in south-west Spain.

    Science.gov (United States)

    Blanco Rodríguez, P; Vera Tomé, F; Lozano, J C

    2014-01-01

    Low-level alpha spectrometry techniques using semiconductor detectors (PIPS) and liquid scintillation (LKB Quantulus 1220™) were used to determine the activity concentration of (238)U, (234)U, (230)Th, (226)Ra, (232)Th, and (210)Pb in soil samples. The soils were collected from an old disused uranium mine located in southwest Spain. The soils were sampled from areas with different levels of influence from the installation and hence had different levels of contamination. The vertical profiles of the soils (down to 40 cm depth) were studied in order to evaluate the vertical distribution of the natural radionuclides. To determine the origin of these natural radionuclides the Enrichment Factor was used. Also, study of the activity ratios between radionuclides belonging to the same radioactive series allowed us to assess the different types of behaviors of the radionuclides involved. The vertical profiles for the radionuclide members of the (238)U series were different at each sampling point, depending on the level of influence of the installation. However, the profiles of each point were similar for the long-lived radionuclides of the (238)U series ((238)U, (234)U, (230)Th, and (226)Ra). Moreover, a major imbalance was observed between (210)Pb and (226)Ra in the surface layer, due to (222)Rn exhalation and the subsequent surface deposition of (210)Pb. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Effectiveness of mineral soil to adsorb the natural occurring radioactive material (norm), uranium and thorium

    Energy Technology Data Exchange (ETDEWEB)

    Amir, Muhammad Nur Iman; Ismail, Nurul Izzatiafifi; Wood, Ab. Khalik, E-mail: khalik@salam.uitm.edu.my; Saat, Ahmad; Hamzah, Zaini [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

    2015-04-29

    A study has been performed on U-soil and Th-soil adsorption of three types of soil collected from Selangor State of Malaysia which are Saujana Putra, Bukit Changgang and Jenderam Hilir. In this study, natural radionuclide (U and Th) soil adsorption based on batch experiments with various initial concentrations of the radionuclide elements were carried out. Parameters that were set constant include pH at 5;amount of soil used was 5 g each, contact time was 24 hour and different initial concentration for each solution of U and Th which is 5 mg/L, 10 mg/L, 15 mg/L, 20 mg/L, 25 mg/L and 40 mg/L were used. The K{sub d} values for each type of soil were determined in this batch experiments which was based on US-EPA method, in order to estimate adsorption capacity of the soil.The K{sub d} values of Th found higher than Kd values of U for all of the soil samples, and the highest was found on the soil collected from Bukit Changgang. The soil clay content was one of factors to influence the adsorption of both U and Th from dilute initial solution. The U-soil and Th-soil adsorption process for all the soil samples studied are generally obeying unimolecular layer Langmuir isotherm model. From Langmuir isotherm, the maximum adsorption capacity for U was 0.393mg/g and for Th was 1.53 mg/g for the soil that was taken from Bukit Changgang. From the study, it suggested that the soil from Bukit Changgang applicable as potential enhanced barrier for site disposing waste containing U and Th.

  16. Fate of soluble uranium in the I{sub 2}/KI leaching process for mercury removal

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, W.D.; Davis, W.H.; Jarabek, R.J. [East Tennessee Technology Park, Oak Ridge, TN (United States). Materials and Chemistry Lab.

    1997-09-01

    General Electric Corporation has developed an extraction and recovery system for mercury, based upon the use of iodine (oxidant) and iodide ion (complexing agent). This system has been proposed for application to select mercury-contaminated mixed waste (i.e., waste containing radionuclides as well as other hazardous constituents), which have been generated by historic activities in support of US Department of Energy (DOE) missions. This system is compared to a system utilizing hypochlorite and chloride ions for removal of mercury and uranium from a sample of authentic mixed waste sludge. Relative to the hypochlorite (bleach) system, the iodine system mobilized more mercury and less uranium from the sludge. An engineering flowsheet has been developed to treat spent iodine-containing extraction medium, allowing the system to be recycled. The fate of soluble uranium in this series of treatment unit operations was monitored by tracing isotopically-enriched uranyl ion into simulated spent extraction medium. Treatment with use of elemental iron is shown to remove > 85% of the traced uranium while concurrently reducing excess iodine to the iodide ion. The next unit operation, adjustment of the solution pH to a value near 12 by the addition of lime slurry to form a metal-laden sludge phase (an operation referred to as lime-softening), removed an additional 57% of soluble uranium activity, for an over-all removal efficiency of {approximately} 96%. However, the precipitated solids did not settle well, and some iodide reagent is held up in the wet filtercake.

  17. Remediation of uranium mill tailings by an integrated biological and chemical process

    Energy Technology Data Exchange (ETDEWEB)

    Torma, A.E.

    1992-01-01

    Dilute calcium chloride brine solution was found to be effective in the solubilization of toxic heavy metals and long half-life radionuclides (Th-230, Ra-226 and Pb-210) from uranium ores and mill tailings. The recovery of heavy metals and radionuclides from uranium mill tailing effluents was studied with calcium alginate beads. The maximum cadmium and zinc uptakes by calcium alginate beads were determined to be 2.8 [times] 10[sup [minus]3] and 2.3 [times] 10[sup [minus]3] mol/dry weight of alginate. The kinetic values, V[sub m] and K, were calculated for uranium uptake by calcium alginate to be 96.2 mg/l/s and 0.125 g/l, respectively.

  18. Remediation of uranium mill tailings by an integrated biological and chemical process

    Energy Technology Data Exchange (ETDEWEB)

    Torma, A.E.

    1992-12-31

    Dilute calcium chloride brine solution was found to be effective in the solubilization of toxic heavy metals and long half-life radionuclides (Th-230, Ra-226 and Pb-210) from uranium ores and mill tailings. The recovery of heavy metals and radionuclides from uranium mill tailing effluents was studied with calcium alginate beads. The maximum cadmium and zinc uptakes by calcium alginate beads were determined to be 2.8 {times} 10{sup {minus}3} and 2.3 {times} 10{sup {minus}3} mol/dry weight of alginate. The kinetic values, V{sub m} and K, were calculated for uranium uptake by calcium alginate to be 96.2 mg/l/s and 0.125 g/l, respectively.

  19. Analytical strategies for uranium determination in natural water and industrial effluents samples; Estrategias analiticas para determinacao de uranio em amostras de aguas e efluentes industriais

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Juracir Silva

    2011-07-01

    The work was developed under the project 993/2007 - 'Development of analytical strategies for uranium determination in environmental and industrial samples - Environmental monitoring in the Caetite city, Bahia, Brazil' and made possible through a partnership established between Universidade Federal da Bahia and the Comissao Nacional de Energia Nuclear. Strategies were developed to uranium determination in natural water and effluents of uranium mine. The first one was a critical evaluation of the determination of uranium by inductively coupled plasma optical emission spectrometry (ICP OES) performed using factorial and Doehlert designs involving the factors: acid concentration, radio frequency power and nebuliser gas flow rate. Five emission lines were simultaneously studied (namely: 367.007, 385.464, 385.957, 386.592 and 409.013 nm), in the presence of HN0{sub 3}, H{sub 3}C{sub 2}00H or HCI. The determinations in HN0{sub 3} medium were the most sensitive. Among the factors studied, the gas flow rate was the most significant for the five emission lines. Calcium caused interference in the emission intensity for some lines and iron did not interfere (at least up to 10 mg L{sup -1}) in the five lines studied. The presence of 13 other elements did not affect the emission intensity of uranium for the lines chosen. The optimized method, using the line at 385.957 nm, allows the determination of uranium with limit of quantification of 30 {mu}g L{sup -1} and precision expressed as RSD lower than 2.2% for uranium concentrations of either 500 and 1000 {mu}g L{sup -1}. In second one, a highly sensitive flow-based procedure for uranium determination in natural waters is described. A 100-cm optical path flow cell based on a liquid-core waveguide (LCW) was exploited to increase sensitivity of the arsenazo 111 method, aiming to achieve the limits established by environmental regulations. The flow system was designed with solenoid micro-pumps in order to improve mixing and

  20. Arabic Natural Language Processing System Code Library

    Science.gov (United States)

    2014-06-01

    Adelphi, MD 20783-1197 This technical note provides a brief description of a Java library for Arabic natural language processing ( NLP ) containing code...for training and applying the Arabic NLP system described in the paper "A Cross-Task Flexible Transition Model for Arabic Tokenization, Affix...processing, NLP , Java, code 14 Stephen C. Tratz (301) 394-2305Unclassified Unclassified Unclassified UU ii Contents 1. Introduction 1 2. File Overview 1 3

  1. Statistical Physics for Natural Language Processing

    CERN Document Server

    Moreno, Juan-Manuel Torres; SanJuan, Eric

    2010-01-01

    In this paper we study the {\\sc Enertex} model that has been applied to fundamental tasks in Natural Language Processing (NLP) including automatic document summarization and topic segmentation. The model is language independent. It is based on the intuitive concept of Textual Energy, inspired by Neural Networks and Statistical Physics of magnetic systems. It can be implemented using simple matrix operations and on the contrary of PageRank algorithms, it avoids any iterative process.

  2. Analyzing Discourse Processing Using a Simple Natural Language Processing Tool

    Science.gov (United States)

    Crossley, Scott A.; Allen, Laura K.; Kyle, Kristopher; McNamara, Danielle S.

    2014-01-01

    Natural language processing (NLP) provides a powerful approach for discourse processing researchers. However, there remains a notable degree of hesitation by some researchers to consider using NLP, at least on their own. The purpose of this article is to introduce and make available a "simple" NLP (SiNLP) tool. The overarching goal of…

  3. Analyzing Discourse Processing Using a Simple Natural Language Processing Tool

    Science.gov (United States)

    Crossley, Scott A.; Allen, Laura K.; Kyle, Kristopher; McNamara, Danielle S.

    2014-01-01

    Natural language processing (NLP) provides a powerful approach for discourse processing researchers. However, there remains a notable degree of hesitation by some researchers to consider using NLP, at least on their own. The purpose of this article is to introduce and make available a "simple" NLP (SiNLP) tool. The overarching goal of…

  4. A natural analogue for copper waste canisters: The copper-uranium mineralised concretions in the Permian mudrocks of south Devon, United Kingdom

    Energy Technology Data Exchange (ETDEWEB)

    Milodowski, A.E.; Styles, M.T.; Hards, V.L. [Natural Environment Research Council (United Kingdom). British Geological Survey

    2000-08-01

    mineralisation and alteration that can be related to the burial and diagenetic history of the Permian strata. The native copper mineralisation exhibits close temporal association with the formation of uraniferous and vanadiferous concretions (known as 'fish-eyes') in the same rocks. Petrographical relationships indicate that both the copper and the 'fish-eye' concretions formed during burial diagenesis but before the maximum compaction of the host mudstone and siltstone. The regional burial history Wessex Basin, indicates that the maximum compaction of the Permian strata would have been achieved by at least the end of the Lower Jurassic (possibly even in the Triassic). Therefore, the native copper mineralisation is older than 176 Ma. The native copper sheets display a complex sequence of alteration and subsequent mineral growth of minerals on their surfaces. The earliest alteration was to copper oxides - principally cuprite with minor tenorite, indicating a change to more oxidising groundwater conditions. The dissolution of native silver and the growth of fringes of copper arsenides followed this. Nickel arsenides and chalcocite, associated with the precipitation of uranium silicates occurred in the later stages of alteration. This suggests a return to a more reducing pore water environment. Again, petrographical relationships indicate that this alteration and subsequent mineralisation is geologically old (i.e. Lower Jurassic or older). Secondary malachite, intimately intergrown copper sulphate and copper oxides, copper chloride, copper-uranium arsenate and uranium vanadates have formed as late-stage alteration products of the native copper and earlier diagenetic cuprite, chalcocite, copper-nickel arsenide and uranium silicate alteration and mineralisation. This latest stage alteration is most probably attributable to near-surface weathering processes. Although the native copper is affected by corrosion, the study has shown that a significant proportion (30

  5. Introduction: Natural Language Processing and Information Retrieval.

    Science.gov (United States)

    Smeaton, Alan F.

    1990-01-01

    Discussion of research into information and text retrieval problems highlights the work with automatic natural language processing (NLP) that is reported in this issue. Topics discussed include the occurrences of nominal compounds; anaphoric references; discontinuous language constructs; automatic back-of-the-book indexing; and full-text analysis.…

  6. The social impact of natural language processing

    DEFF Research Database (Denmark)

    Hovy, Dirk; Spruit, Shannon

    Research in natural language processing (NLP) used to be mostly performed on anonymous corpora, with the goal of enriching linguistic analysis. Authors were either largely unknown or public figures. As we increasingly use more data from social media, this situation has changed: users are now...

  7. Uranium-Loaded Water Treatment Resins: 'Equivalent Feed' at NRC and Agreement State-Licensed Uranium Recovery Facilities - 12094

    Energy Technology Data Exchange (ETDEWEB)

    Camper, Larry W.; Michalak, Paul; Cohen, Stephen; Carter, Ted [Nuclear Regulatory Commission (United States)

    2012-07-01

    Community Water Systems (CWSs) are required to remove uranium from drinking water to meet EPA standards. Similarly, mining operations are required to remove uranium from their dewatering discharges to meet permitted surface water discharge limits. Ion exchange (IX) is the primary treatment strategy used by these operations, which loads uranium onto resin beads. Presently, uranium-loaded resin from CWSs and mining operations can be disposed as a waste product or processed by NRC- or Agreement State-licensed uranium recovery facilities if that licensed facility has applied for and received permission to process 'alternate feed'. The disposal of uranium-loaded resin is costly and the cost to amend a uranium recovery license to accept alternate feed can be a strong disincentive to commercial uranium recovery facilities. In response to this issue, the NRC issued a Regulatory Issue Summary (RIS) to clarify the agency's policy that uranium-loaded resin from CWSs and mining operations can be processed by NRC- or Agreement State-licensed uranium recovery facilities without the need for an alternate feed license amendment when these resins are essentially the same, chemically and physically, to resins that licensed uranium recovery facilities currently use (i.e., equivalent feed). NRC staff is clarifying its current alternate feed policy to declare IX resins as equivalent feed. This clarification is necessary to alleviate a regulatory and financial burden on facilities that filter uranium using IX resin, such as CWSs and mine dewatering operations. Disposing of those resins in a licensed facility could be 40 to 50 percent of the total operations and maintenance (O and M) cost for a CWS. Allowing uranium recovery facilities to treat these resins without requiring a license amendment lowers O and M costs and captures a valuable natural resource. (authors)

  8. 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.

  9. Uranium dioxide electrolysis

    Science.gov (United States)

    Willit, James L [Batavia, IL; Ackerman, John P [Prescott, AZ; Williamson, Mark A [Naperville, IL

    2009-12-29

    This is a single stage process for treating spent nuclear fuel from light water reactors. The spent nuclear fuel, uranium oxide, UO.sub.2, is added to a solution of UCl.sub.4 dissolved in molten LiCl. A carbon anode and a metallic cathode is positioned in the molten salt bath. A power source is connected to the electrodes and a voltage greater than or equal to 1.3 volts is applied to the bath. At the anode, the carbon is oxidized to form carbon dioxide and uranium chloride. At the cathode, uranium is electroplated. The uranium chloride at the cathode reacts with more uranium oxide to continue the reaction. The process may also be used with other transuranic oxides and rare earth metal oxides.

  10. Environmental assessment of remedial action at the Naturita Uranium processing site near Naturita, Colorado. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    1993-08-01

    The proposed remedial action for the Naturita processing site is relocation of the contaminated materials and debris to the Dry Flats disposal site, 6 road miles (mi) [ 1 0 kilometers (km)] to the southeast. At the disposal site, the contaminated materials would be stabilized and covered with layers of earth and rock. The proposed disposal site is on land administered by the Bureau of Land Management (BLM) and used primarily for livestock grazing. The final disposal site would cover approximately 57 ac (23 ha), which would be permanently transferred from the BLM to the DOE and restricted from future uses. The remedial action activities would be conducted by the DOE`s Uranium Mill Tailings Remedial Action (UMTRA) Project. The remedial action would result in the loss of approximately 164 ac (66 ha) of soils, but 132 ac (53 ha) of these soils are contaminated and cannot be used for other purposes. Another 154 ac (62 ha) of soils would be temporarily disturbed. Approximately 57 ac (23 ha) of open range land would be permanently removed from livestock grazing and wildlife use. The removal of the contaminated materials would affect the 1 00-year floodplain of the San Miguel River and would result in the loss of riparian habitat along the river. The southwestern willow flycatcher, a Federal candidate species, may be affected by the remedial action, and the use of water from the San Miguel River ``may affect`` the Colorado squawfish, humpback chub, bonytail chub, and razorback sucker. Traffic levels on State Highways 90 and 141 would be increased during the remedial action, as would the noise levels along these transportation routes. Measures for mitigating the adverse environmental impacts of the proposed remedial action are discussed in Section 6.0 of this environmental assessment (EA).

  11. UPGRADING NATURAL GAS VIA MEMBRANE SEPARATION PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    S.A.Stern; P.A. Rice; J. Hao

    2000-03-01

    The objective of the present study is to assess the potential usefulness of membrane separation processes for removing CO{sub 2} and H{sub 2}S from low-quality natural gas containing substantial amounts of both these ''acid'' gases, e.g., up to 40 mole-% CO{sub 2} and 10 mole-% H{sub 2}S. The membrane processes must be capable of upgrading the crude natural gas to pipeline specifications ({le} 2 mole-% CO{sub 2}, {le} 4 ppm H{sub 2}S). Moreover, these processes must also be economically competitive with the conventional separation techniques, such as gas absorption, utilized for this purpose by the gas industry.

  12. 31 CFR 540.316 - Uranium enrichment.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium enrichment. 540.316 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.316 Uranium enrichment. The term uranium enrichment means the process...

  13. Evapotranspiration And Geochemical Controls On Groundwater Plumes At Arid Sites: Toward Innovative Alternate End-States For Uranium Processing And Tailings Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Looney, Brian B.; Denham, Miles E.; Eddy-Dilek, Carol A.; Millings, Margaret R.; Kautsky, Mark

    2014-01-08

    Management of legacy tailings/waste and groundwater contamination are ongoing at the former uranium milling site in Tuba City AZ. The tailings have been consolidated and effectively isolated using an engineered cover system. For the existing groundwater plume, a system of recovery wells extracts contaminated groundwater for treatment using an advanced distillation process. The ten years of pump and treat (P&T) operations have had minimal impact on the contaminant plume – primarily due to geochemical and hydrological limits. A flow net analysis demonstrates that groundwater contamination beneath the former processing site flows in the uppermost portion of the aquifer and exits the groundwater as the plume transits into and beneath a lower terrace in the landscape. The evaluation indicates that contaminated water will not reach Moenkopi Wash, a locally important stream. Instead, shallow groundwater in arid settings such as Tuba City is transferred into the vadose zone and atmosphere via evaporation, transpiration and diffuse seepage. The dissolved constituents are projected to precipitate and accumulate as minerals such as calcite and gypsum in the deep vadose zone (near the capillary fringe), around the roots of phreatophyte plants, and near seeps. The natural hydrologic and geochemical controls common in arid environments such as Tuba City work together to limit the size of the groundwater plume, to naturally attenuate and detoxify groundwater contaminants, and to reduce risks to humans, livestock and the environment. The technical evaluation supports an alternative beneficial reuse (“brownfield”) scenario for Tuba City. This alternative approach would have low risks, similar to the current P&T scenario, but would eliminate the energy and expense associated with the active treatment and convert the former uranium processing site into a resource for future employment of local citizens and ongoing benefit to the Native American Nations.

  14. The study of capability natural uranium as fuel cycle input for long life gas cooled fast reactors with helium as coolant

    Science.gov (United States)

    Ariani, Menik; Satya, Octavianus Cakra; Monado, Fiber; Su'ud, Zaki; Sekimoto, Hiroshi

    2016-03-01

    The objective of the present research is to assess the feasibility design of small long-life Gas Cooled Fast Reactor with helium as coolant. GCFR included in the Generation-IV reactor systems are being developed to provide sustainable energy resources that meet future energy demand in a reliable, safe, and proliferation-resistant manner. This reactor can be operated without enrichment and reprocessing forever, once it starts. To obtain the capability of consuming natural uranium as fuel cycle input modified CANDLE burn-up scheme was adopted in this system with different core design. This study has compared the core with three designs of core reactors with the same thermal power 600 MWth. The fuel composition each design was arranged by divided core into several parts of equal volume axially i.e. 6, 8 and 10 parts related to material burn-up history. The fresh natural uranium is initially put in region 1, after one cycle of 10 years of burn-up it is shifted to region 2 and the region 1 is filled by fresh natural uranium fuel. This concept is basically applied to all regions, i.e. shifted the core of the region (i) into region (i+1) region after the end of 10 years burn-up cycle. The calculation results shows that for the burn-up strategy on "Region-8" and "Region-10" core designs, after the reactors start-up the operation furthermore they only needs natural uranium supply to the next life operation until one period of refueling (10 years).

  15. The study of capability natural uranium as fuel cycle input for long life gas cooled fast reactors with helium as coolant

    Energy Technology Data Exchange (ETDEWEB)

    Ariani, Menik, E-mail: menikariani@gmail.com; Satya, Octavianus Cakra; Monado, Fiber [Department of Physics, Faculty of Mathematics and Natural Sciences, Sriwijaya University, jl Palembang-Prabumulih km 32 Indralaya OganIlir, South of Sumatera (Indonesia); Su’ud, Zaki [Nuclear and Biophysics Research Division, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, jlGanesha 10, Bandung (Indonesia); Sekimoto, Hiroshi [CRINES, Tokyo Institute of Technology, 2-12-11N1-17 Ookayama, Meguro-Ku, Tokyo (Japan)

    2016-03-11

    The objective of the present research is to assess the feasibility design of small long-life Gas Cooled Fast Reactor with helium as coolant. GCFR included in the Generation-IV reactor systems are being developed to provide sustainable energy resources that meet future energy demand in a reliable, safe, and proliferation-resistant manner. This reactor can be operated without enrichment and reprocessing forever, once it starts. To obtain the capability of consuming natural uranium as fuel cycle input modified CANDLE burn-up scheme was adopted in this system with different core design. This study has compared the core with three designs of core reactors with the same thermal power 600 MWth. The fuel composition each design was arranged by divided core into several parts of equal volume axially i.e. 6, 8 and 10 parts related to material burn-up history. The fresh natural uranium is initially put in region 1, after one cycle of 10 years of burn-up it is shifted to region 2 and the region 1 is filled by fresh natural uranium fuel. This concept is basically applied to all regions, i.e. shifted the core of the region (i) into region (i+1) region after the end of 10 years burn-up cycle. The calculation results shows that for the burn-up strategy on “Region-8” and “Region-10” core designs, after the reactors start-up the operation furthermore they only needs natural uranium supply to the next life operation until one period of refueling (10 years).

  16. Column Testing and 1D Reactive Transport Modeling to Evaluate Uranium Plume Persistence Processes

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Raymond H. [Navarro Research and Engineering, Inc.; Morrison, Stan [Navarro Research and Engineering, Inc.; Morris, Sarah [Navarro Research and Engineering, Inc.; Tigar, Aaron [Navarro Research and Engineering, Inc.; Dam, William [U.S. Department of Energy, Office of Legacy Management; Dayvault, Jalena [U.S. Department of Energy, Office of Legacy Management

    2016-04-26

    Motivation for Study: Natural flushing of contaminants at various U.S. Department of Energy Office of Legacy Management sites is not proceeding as quickly as predicted (plume persistence) Objectives: Help determine natural flushing rates using column tests. Use 1D reactive transport modeling to better understand the major processes that are creating plume persistence Approach: Core samples from under a former mill tailings area Tailings have been removed. Column leaching using lab-prepared water similar to nearby Gunnison River water. 1D reactive transport modeling to evaluate processes

  17. Characteristic Analysis for the Recycled Uranium of the Pyroprocess

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chang Je; Ryu, Ho Jin; Na, Sang Ho; Kang, Kweon Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-11-15

    In order to recover uranium and TRU from spent nuclear fuels, a pyroprocessing has been developed through a dry and metallurgical reprocess technology using a series of electrolyses such as an electro-reduction, an electro-refining, and an electro-winning. When the spent fuel is being fed into the pyroprocess, most of the uranium is gathered in metallic form around a solid cathode during an electro-refining process. It is expected that the recovered uranium will be sent to a spent fuel storage site after converting it into a metal ingot form to reduce its storage space and transportation burden. However, the weight percent of U-235 in the recovered uranium is about 0.9 wt% and it is sufficiently re-utilized in a heavy water reactor which uses a natural uranium fuel. The reuse of recovered uranium will bring not only a huge economical profit and save of uranium resources but also an alleviation of burden on the management and disposal of the spent fuel. A previous research on recycling of recovered uranium was carried out and most of the recovered uranium was assumed to be imported from abroad at that time. The preliminary results showed there is a sufficient possibility to recycle recovered uranium in terms of a reactor's characteristics as well as the fuel performance. And the DUPIC (direct use of spent pressurized water reactor fuel into CANDU reactor) program has also been performed and demonstrated the fundamental technologies. The recovered uranium from a pyroprocess contains some TRU as an impurity and it will exhibit a slightly different behavior from the previous recycling options. In this report, the reactor's characteristics including discharge burnup are investigated based on the lattice calculations which are performed for the CANFELX bundle.

  18. Near-threshold photoionization of hydrogenlike uranium studied in ion-atom collisions via the time-reversed process.

    Science.gov (United States)

    Stöhlker, T; Ma, X; Ludziejewski, T; Beyer, H F; Bosch, F; Brinzanescu, O; Dunford, R W; Eichler, J; Hagmann, S; Ichihara, A; Kozhuharov, C; Krämer, A; Liesen, D; Mokler, P H; Stachura, Z; Swiat, P; Warczak, A

    2001-02-05

    Radiative electron capture, the time-reversed photoionization process occurring in ion-atom collisions, provides presently the only access to photoionization studies for very highly charged ions. By applying the deceleration mode of the ESR storage ring, we studied this process in low-energy collisions of bare uranium ions with low- Z target atoms. This technique allows us to extend the current information about photoionization to much lower energies than those accessible for neutral heavy elements in the direct reaction channel. The results prove that for high- Z systems, higher-order multipole contributions and magnetic corrections persist even at energies close to the threshold.

  19. Phonetic Dictionary for Natural Language Processing: Kannada

    Directory of Open Access Journals (Sweden)

    Mallamma V. Reddy

    2014-07-01

    Full Text Available India has 22 officially recognized languages: Assamese, Bengali, English, Gujarati, Hindi, Kannada, Kashmiri, Konkani, Malayalam, Manipuri, Marathi, Nepali, Oriya, Punjabi, Sanskrit, Tamil, Telugu, and Urdu. Clearly, India owns the language diversity problem. In the age of Internet, the multiplicity of languages makes it even more necessary to have sophisticated Systems for Natural Language Process. In this paper we are developing the phonetic dictionary for natural language processing particularly for Kannada. Phonetics is the scientific study of speech sounds. Acoustic phonetics studies the physical properties of sounds and provides a language to distinguish one sound from another in quality and quantity. Kannada language is one of the major Dravidian languages of India. The language uses forty nine phonemic letters, divided into three groups: Swaragalu (thirteen letters; Yogavaahakagalu (two letters; and Vyanjanagalu (thirty-four letters, similar to the vowels and consonants of English, respectively.

  20. An expert system for natural language processing

    Science.gov (United States)

    Hennessy, John F.

    1988-01-01

    A solution to the natural language processing problem that uses a rule based system, written in OPS5, to replace the traditional parsing method is proposed. The advantage to using a rule based system are explored. Specifically, the extensibility of a rule based solution is discussed as well as the value of maintaining rules that function independently. Finally, the power of using semantics to supplement the syntactic analysis of a sentence is considered.

  1. Introduction to Chinese natural language processing

    CERN Document Server

    Wong, Kam-Fai; Xu, Ruifeng; Zhang, Zheng-sheng

    2009-01-01

    This book introduces Chinese language-processing issues and techniques to readers who already have a basic background in natural language processing (NLP). Since the major difference between Chinese and Western languages is at the word level, the book primarily focuses on Chinese morphological analysis and introduces the concept, structure, and interword semantics of Chinese words.The following topics are covered: a general introduction to Chinese NLP; Chinese characters, morphemes, and words and the characteristics of Chinese words that have to be considered in NLP applications; Chinese word

  2. Solid-phase extraction-spectrophotometric determination of uranium(VI) in natural waters

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Susan; Mohammadzadeh, Darush [Department of Chemistry, University of Birjand, Birjand (Iran); Yamini, Yadollah [Department of Chemistry, Tarbiat Moddars University, Tehran (Iran)

    2003-03-01

    A method for the extraction and determination of uranyl ion in natural waters using octadecyl bonded silica membrane disks modified with piroxicam and spectrophotometry with arsenazo(III) is proposed. The perconcentration step was studied with regard to experimental parameters such as amount of extractant, type and amount of eluent, pH, flow rates and tolerance limit of diverse ions on the recovery of uranyl ion. The limit of detection of the proposed method is 0.4 {mu}g L{sup -1} of uranyl. The method was applied to the recovery of uranyl from different water samples. (orig.)

  3. Spectroscopic studies of uranium species for environmental decontamination applications

    Science.gov (United States)

    Eng, Charlotte

    After the Cold War, Department of Energy began to concentrate its efforts on cleanup of former nuclear material processing facilities, especially uranium-contaminated groundwater and soil. This research aims to study uranium association to both organic and inorganic compounds found in the contaminated environment in the hopes that the information gathered can be applied to the development and optimization of cost-effective remediation techniques. Spectroscopic and electrochemical methods will be employed to examine the behavior of uranium in given conditions to further our understanding of its impact on the environment. Uranium found in groundwater and soil bind with various ligands, especially organic ligands present in the environment due to natural sources (e.g. metabolic by-products or degradation of plants and animals) or man-made sources (e.g. chelating agents used in operating or cleanup of uranium processing facilities). We selected reasonable analogs of naturally occurring matter and studied their structure, chemical and electrochemical behavior and found that the structure of uranyl complexes depends heavily on the nature of the ligand and environmental factors such as pH. Association of uranium-organic complexes with anaerobic bacteria, Clostridium sp. was studied to establish if the bacteria can effectively bioreduce uranium while going through normal bacterial activity. It was found that the nature of the organic ligand affected the bioavailability and toxicity of the uranium on the bacteria. In addition, we have found that the type of iron corrosion products and uranyl species present on the surface of corroded steel depended on various environmental factors, which subsequently affected the removal rate of uranium by a citric acid/hydrogen peroxide/deionized water cleaning process. The method was found to remove uranium from only the topmost corrosion layers and residual uranium could be found (a) deeper in the corrosion layers where it is occluded by

  4. Determination of the elemental concentration of uranium and thorium in the products and by-products of amang tin tailings process

    Science.gov (United States)

    Alnour, I. A.; Wagiran, H.; Ibrahim, N.; Hamzah, S.; Elias, M. S.

    2017-01-01

    Amang or tin tailing is processed into concentrated ores and other economical valuable minerals such as monazite, zircon, xenotime, ilmenite etc. Besides that, the tailings from these ores may have a significant potential source of radiation exposure to amang plants' workers. This study was conducted to determine the elemental concentration of uranium and thorium in mineral samples collected from five amang tailing factories. The concentration of uranium and thorium was carried out by using instrumental neutron activation analysis (INAA) relative technique. The concentration of uranium and thorium in ppm obtained in this study are as follows: raw (189-1064) and (622-4965); monazite (1076-1988) and (3467-33578); xenotime 4053 and 5540; zircon (309-3090) and (387-6339); ilmenite (104-583) and (88-1205); rutile (212-889) and (44-1119); pyrite (7-43) and (9-132); and waste (5-338) and (9-1218) respectively. The analysis results shows that the monazite, xenotime and zircon have high content of uranium and thorium, whereas ilmenite, rutile, pyrite and waste have lower concentration compare with raw materials after tailing process. The highest values of uranium and thorium concentrations (4053 ± 428 ppm and 33578 ± 873 ppm, respectively) were observed in xenotime and monazite; whereas the lowest value was 5.48 ± 0.86 ppm of uranium recorded in waste (sand) and 9 ± 0.32 ppm of thorium for waste (sand) and pyrite.

  5. Gasoline from natural gas by sulfur processing

    Energy Technology Data Exchange (ETDEWEB)

    Erekson, E.J.; Miao, F.Q. [Institute of Gas Technology, Des Plaines, IL (United States)

    1995-12-31

    The overall objective of this research project is to develop a catalytic process to convert natural gas to liquid transportation fuels. The process, called the HSM (Hydrogen Sulfide-Methane) Process, consists of two steps that each utilize a catalyst and sulfur-containing intermediates: (1) converting natural gas to CS{sub 2} and (2) converting CS{sub 2} to gasoline range liquids. Catalysts have been found that convert methane to carbon disulfide in yields up to 98%. This exceeds the target of 40% yields for the first step. The best rate for CS{sub 2} formation was 132 g CS{sub 2}/kg-cat-h. The best rate for hydrogen production is 220 L H{sub 2} /kg-cat-h. A preliminary economic study shows that in a refinery application hydrogen made by the HSM technology would cost $0.25-R1.00/1000 SCF. Experimental data will be generated to facilitate evaluation of the overall commercial viability of the process.

  6. Characterization and remediation of soils contaminated with uranium.

    Science.gov (United States)

    Gavrilescu, Maria; Pavel, Lucian Vasile; Cretescu, Igor

    2009-04-30

    Environmental contamination caused by radionuclides, in particular by uranium and its decay products is a serious problem worldwide. The development of nuclear science and technology has led to increasing nuclear waste containing uranium being released and disposed in the environment. The objective of this paper is to develop a better understanding of the techniques for the remediation of soils polluted with radionuclides (uranium in particular), considering: the chemical forms of uranium, including depleted uranium (DU) in soil and other environmental media, their characteristics and concentrations, and some of the effects on environmental and human health; research issues concerning the remediation process, the benefits and results; a better understanding of the range of uses and situations for which each is most appropriate. The paper addresses the main features of the following techniques for uranium remediation: natural attenuation, physical methods, chemical processes (chemical extraction methods from contaminated soils assisted by various suitable chelators (sodium bicarbonate, citric acid, two-stage acid leaching procedure), extraction using supercritical fluids such as solvents, permeable reactive barriers), biological processes (biomineralization and microbial reduction, phytoremediation, biosorption), and electrokinetic methods. In addition, factors affecting uranium removal from soils are furthermore reviewed including soil characteristics, pH and reagent concentration, retention time.

  7. Occurrence of fungus Rhizopus sp in bioassays with Allium cepa germinated in the presence of uranium to study the effect of natural radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Xavier, Magno N.; Oliveira, Andressa L.; Maffei, Eliane M.D.; Campos, Simara S., E-mail: simaracampos@gmail.com [Universidade Estadual do Sudoeste da Bahia (UESB), Vitoria da Conquista, BA (Brazil). Departamento de Ciencias Exatas e Tecnologicas; Gennari, Roseli F. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica. Departamento de Fisica Nuclear

    2015-07-01

    The demographic and global economic growth has promoted increasing power consumption. In this context, several studies point to nuclear energy as being promising to meet such demand. Although Brazil composes the seventh position in the world ranking of uranium reserves, the ore is still little explored in Brazil, considering its vast existing arsenal. On the one hand, despite nuclear energy has brought great benefits, technological and socio-economic development, it generates controversy about environmental contamination and risks to public health. Studies on this subject indicate that areas where uranium ore concentration is high, natural environmental radiation exposure levels are already higher than in other regions. The aim of this study is to observe the simple germination of the bio-indicator (Allium cepa), typically used to assess potential chromosomal aberrations, suffer any adverse effect caused by natural radiation uranium. The choice of this bio-indicator is based on its potential for evaluating the mutation caused by countless chemical compounds. Four treatments with three replicates were designed. In each treatment, 10 seeds of onion A. cepa without any pesticides were packed in the Petri dish lined with germination paper and room temperature (25°C) was kept until the root reaches approximately 1cm long. As a result, growth of the fungus Rhizopus sp was observed, in the experiments where uranium ore was added. It is important to mention according to the literature, this fungus can cause serious infections (and often fatal) in humans and animals, due to its high growth rate and also to their ability on surviving in relatively high temperatures. (author)

  8. The uranium in the environment; L'uranium dans l'environnement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The uranium is a natural element omnipresent in the environment, with a complex chemistry more and more understood. Many studies are always today devoted to this element to better improve the uranium behavior in the environment. To illustrate this knowledge and for the public information the CEA published this paper. It gathers in four chapters: historical aspects and properties of the uranium, the uranium in the environment and the impacts, the metrology of the uranium and its migration. (A.L.B.)

  9. Understanding uranium behaviour at the Askola uranium mineralization

    Energy Technology Data Exchange (ETDEWEB)

    Jokelainen, L.; Siitari-Kauppi, M. [Univ. of Helsinki, Helsinki Univ. (Finland); Markovaara-Koivisto, M. [Helsinki Univ. of Technology, TKK (Finland); Read, D. [Enterpris, The Old Library, Lower Shott, Great Bookham, Surrey (United Kingdom); Lindberg, A. [Geological Survey of Finland, Espoo (Finland); Hellmuth, K.H. [Radiation and Nuclear Safety Authority, Helsinki (Finland)

    2010-07-01

    Understanding the behaviour of uranium is essential when assessing the safety of a spent nuclear fuel repository. The geochemical behaviour of uranium, including its reactive transport chemistry, is also a matter of concern when assessing the environmental impact of uranium mining. Subsurface uranium mobility is believed to be primarily controlled by dissolution and (co)-precipitation of uranium mineral solids and adsorption to mineral surfaces. This paper describes a modelling exercise based on characterisation of samples taken from drilled cores at the uranium mineralization at Askola, Southern Finland. In the modelling exercise, current conditions are assumed to be oxidizing and saturated with groundwater. PHREEQC was used for modelling in conjunction with the Lawrence Livermore National Laboratory database, chosen for its extensive coverage of uranium species and mineral phases. It is postulated that weathering processes near the surface have led to uranium dissolution from the primary ore, leaching out from the matrix and migrating along water-conducting fractures with subsequent re-diffusion into the rock matrix. Electron microscopy studies show that precipitated uranium occupies intra-granular fractures in feldspars and quartz. In addition, secondary uranium was found to be distributed within goethite nodules as well as around the margins of iron-containing minerals in the form of silicate and phosphate precipitates. Equilibrium modelling calculations predict that uranium would be precipitated as uranyl silicates, most likely soddyite and uranophane, in the prevailing chemical conditions beneath Lakeakallio hill. (orig.)

  10. Production Cycle for Large Scale Fission Mo-99 Separation by the Processing of Irradiated LEU Uranium Silicide Fuel Element Targets

    Directory of Open Access Journals (Sweden)

    Abdel-Hadi Ali Sameh

    2013-01-01

    Full Text Available Uranium silicide fuels proved over decades their exceptional qualification for the operation of higher flux material testing reactors with LEU elements. The application of such fuels as target materials, particularly for the large scale fission Mo-99 producers, offers an efficient and economical solution for the related facilities. The realization of such aim demands the introduction of a suitable dissolution process for the applied U3Si2 compound. Excellent results are achieved by the oxidizing dissolution of the fuel meat in hydrofluoric acid at room temperature. The resulting solution is directly behind added to an over stoichiometric amount of potassium hydroxide solution. Uranium and the bulk of fission products are precipitated together with the transuranium compounds. The filtrate contains the molybdenum and the soluble fission product species. It is further treated similar to the in-full scale proven process. The generated off gas stream is handled also as experienced before after passing through KOH washing solution. The generated alkaline fluoride containing waste solution is noncorrosive. Nevertheless fluoride can be selectively bonded as in soluble CaF2 by addition of a mixture of solid calcium hydroxide calcium carbonate to the sand cement mixture used for waste solidification. The generated elevated amounts of LEU remnants can be recycled and retargeted. The related technology permits the minimization of the generated fuel waste, saving environment, and improving processing economy.

  11. Mobility in process calculi and natural computing

    CERN Document Server

    Aman, Bogdan

    2011-01-01

    The design of formal calculi in which fundamental concepts underlying interactive systems can be described and studied has been a central theme of theoretical computer science in recent decades, while membrane computing, a rule-based formalism inspired by biological cells, is a more recent field that belongs to the general area of natural computing. This is the first book to establish a link between these two research directions while treating mobility as the central topic. In the first chapter the authors offer a formal description of mobility in process calculi, noting the entities that move

  12. Natural language processing, pragmatics, and verbal behavior.

    Science.gov (United States)

    Cherpas, C

    1992-01-01

    Natural Language Processing (NLP) is that part of Artificial Intelligence (AI) concerned with endowing computers with verbal and listener repertoires, so that people can interact with them more easily. Most attention has been given to accurately parsing and generating syntactic structures, although NLP researchers are finding ways of handling the semantic content of language as well. It is increasingly apparent that understanding the pragmatic (contextual and consequential) dimension of natural language is critical for producing effective NLP systems. While there are some techniques for applying pragmatics in computer systems, they are piecemeal, crude, and lack an integrated theoretical foundation. Unfortunately, there is little awareness that Skinner's (1957) Verbal Behavior provides an extensive, principled pragmatic analysis of language. The implications of Skinner's functional analysis for NLP and for verbal aspects of epistemology lead to a proposal for a "user expert"-a computer system whose area of expertise is the long-term computer user. The evolutionary nature of behavior suggests an AI technology known as genetic algorithms/programming for implementing such a system.

  13. Applications of text processing using natural processing system in Printer

    Science.gov (United States)

    Saito, Tadashi

    DAI NIPPON PRINTING CO., Ltd. developed a natural language processing system for the automatic indexing and assorting readable kana characters to kanji characters, which is called ruby. This system based on the automatic indexing system called INDEXER produced by NTT Communications and Information Processing Laboratories and NTT Data Communications Co., Ltd. This paper describes some applications using the system. This system creates kana characters for kanji characters which is useful for address books, name lists and books. Further we apply this system for an automatic indexing on CD-ROM.

  14. Natural and anthropogenic enrichments of molybdenum, thorium, and uranium in a complete peat bog profile, Jura Mountains, Switzerland.

    Science.gov (United States)

    Krachler, Michael; Shotyk, William

    2004-05-01

    A core from an ombrotrophic Swiss bog representing 12 370 (14)C years of peat accumulation was evaluated as a possible archive of atmospheric deposition of Mo, Th and U. Calcium, Sr, and Ba were also determined to quantify weathering inputs, Mn to follow possible redox transformations, and Rb to identify plant uptake. Each of these elements was determined using ICP-MS, following digestion in a microwave heated autoclave using 3 ml HNO(3) and 0.1 ml HBF(4). Calcium and Sr clearly identify the thickness of the ombrotrophic zone because they are enriched in the minerogenic zone relative to the concentration of mineral matter. The concentration of Ba, however, is proportional to the concentration of mineral matter in all samples, and is not added to peat column by weathering reactions at the peat-sediment interface. The lowest element concentrations are found during the Holocene climate optimum (5320 to 8030 (14)C year BP) with the following natural background values (n= 18): Mo 0.08 +/- 0.02 microg g(-1), U 0.029 +/- 0.008 microg g(-1), Ba 5.2 +/- 2.6 microg g(-1), Th 0.070 +/- 0.022 microg g(-1) and Rb 0.63 +/- 0.09 microg g(-1). By far the highest concentrations of Ba, Mn, Rb and Th were found during the Younger Dryas cold climate event (10 590 (14)C year BP) when the flux of atmospheric soil dust was at its post-glacial maximum. Molybdenum and U are elevated in concentration throughout the minerogenic zone because of sediment weathering and this masks the atmospheric signal in samples older than ca. 8000 (14)C year BP (ca. 9000 calendar years). Enrichment factors (EF) calculated using Sc as a conservative, lithogenic element shows that minerogenic peats are enriched in Mo up to 18x and U 26x, relative to the natural "background" values. During the two millennia prior to industrialisation, the accumulation rate of atmospheric Mo averaged 0.23 +/- 0.13 microg m(-2) year(-1). With the onset of the Industrial Revolution, Mo accumulation rates rapidly and continuously

  15. Learning from bacteria about natural information processing.

    Science.gov (United States)

    Ben-Jacob, Eshel

    2009-10-01

    Under natural growth conditions, bacteria live in complex hierarchical communities. To conduct complex cooperative behaviors, bacteria utilize sophisticated communication to the extent that their chemical language includes semantic and even pragmatic aspects. I describe how complex colony forms (patterns) emerge through the communication-based interplay between individual bacteria and the colony. Individual cells assume newly co-generated traits and abilities that are not prestored in the genetic information of the cells, that is, not all the information required for efficient responses to all environmental conditions is stored. To solve newly encountered problems, they assess the problem via collective sensing, recall stored information of past experience, and then execute distributed information processing of the 10(9)-10(12) bacteria in the colony--transforming the colony into a "super-brain." I show illuminating examples of swarming intelligence of live bacteria in which they solve optimization problems that are beyond what human beings can solve. This will lead to a discussion about the special nature of bacterial computational principles compared to Turing algorithm computational principles, in particular about the role of distributed information processing.

  16. Optimization and validation of a chemical process for uranium, mercury and cesium leaching from cemented radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    Reynier, N.; Lastra, R.; Laviolette, C.; Bouzoubaa, N., E-mail: nicolas.reynier@canada.ca [Natural Resources Canada, CanmetMINING, Ottawa, Ontario (Canada); Chapman, M. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2015-12-15

    Canadian Nuclear Laboratories (CNL) is developing a treatment and long-term management strategy for a legacy cemented radioactive waste that contains uranium, mercury, and fission products. Extracting the uranium would be advantageous for decreasing the waste classification and reducing the cost of long-term management. The chemical leachability of 3 key elements (U, Hg, and Cs) from a surrogate cemented waste (SCW) was studied with several lixiviants. The results showed that the most promising approach to leach and recover U, Hg, and Cs is the direct leaching of the SCW with H{sub 2}SO{sub 4} in strong saline media. Operating parameters such as particle size, temperature, pulp density, leaching time, acid and salt concentrations, number of leaching/washing steps, etc. were optimized to improve key elements solubilization. Sulfuric leaching in saline media of a SCW (U5) containing 1182 ppm of U, 1598 ppm of Hg, and 7.9 ppm of Cs in the optimized conditions allows key elements solubilisation of 98.5 ± 0.4%, 96.6 ± 0.1%, and 93.8 ± 1.1% of U, Hg, and Cs, respectively. This solubilization process was then applied in triplicate to 7 other SCWs prepared with different cements, liquid ratios, and at different aging times and temperatures. Concentrated sulfuric acid is added to the slurry until the pH is about 2, which causes the complete degradation of cement and the formation of CaSO{sub 4}. Sulfuric acid is particularly useful because it produces a leachate that is amenable to conventional ion exchange technology for the separation and recovery of uranium. (author)

  17. Megascale processes: Natural disasters and human behavior

    Science.gov (United States)

    Kieffer, S.W.; Barton, P.; Chesworth, W.; Palmer, A.R.; Reitan, P.; Zen, E.-A.

    2009-01-01

    Megascale geologic processes, such as earthquakes, tsunamis, volcanic eruptions, floods, and meteoritic impacts have occurred intermittently throughout geologic time, and perhaps on several planets. Unlike other catastrophes discussed in this volume, a unique process is unfolding on Earth, one in which humans may be the driving agent of megadisasters. Although local effects on population clusters may have been catastrophic in the past, human societies have never been interconnected globally at the scale that currently exists. We review some megascale processes and their effects in the past, and compare present conditions and possible outcomes. We then propose that human behavior itself is having effects on the planet that are comparable to, or greater than, these natural disasters. Yet, unlike geologic processes, human behavior is potentially under our control. Because the effects of our behavior threaten the stability, or perhaps even existence, of a civilized society, we call for the creation of a body to institute coherent global, credible, scientifi cally based action that is sensitive to political, economic, religious, and cultural values. The goal would be to institute aggressive monitoring, identify and understand trends, predict their consequences, and suggest and evaluate alternative actions to attempt to rescue ourselves and our ecosystems from catastrophe. We provide a template modeled after several existing national and international bodies. ?? 2009 The Geological Society of America.

  18. Absorbed Dose Rate Due to Intake of Natural Radionuclides by Tilapia Fish (Tilapia nilotica,Linnaeus, 1758) Estimated Near Uranium Mining at Caetité, Bahia, Brazil

    Science.gov (United States)

    Pereira, Wagner de S.; Kelecom, Alphonse; Py Júnior, Delcy de Azevedo

    2008-08-01

    The uranium mining at Caetité (Uranium Concentrate Unit—URA) is in its operational phase. Aiming to estimate the radiological environmental impact of the URA, a monitoring program is underway. In order to preserve the biota of the deleterious effects from radiation and to act in a pro-active way as expected from a licensing body, the present work aims to use an environmental protection methodology based on the calculation of absorbed dose rate in biota. Thus, selected target organism was the Tilapia fish (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). As, in Brazil there are no radiation exposure limits adopted for biota the value proposed by the Department of Energy (DOE) of the United States of 3.5×103 μGy y-1 has been used. The derived absorbed dose rate calculated for Tilapia was 2.51×100 μGy y-1, that is less than 0.1% of the dose limit established by DOE. The critical radionuclide was Ra-226, with 56% of the absorbed dose rate, followed by U-238 with 34% and Th-232 with 9%. This value of 0.1% of the limit allows to state that, in the operational conditions analyzed, natural radionuclides do not represent a radiological problem to biota.

  19. Dating by fission track method: study of neutron dosimetry with natural uranium thin films; Datacao com o metodo dos tracos de fissao: estudo da dosimetria de neutrons com filmes finos de uranio natural

    Energy Technology Data Exchange (ETDEWEB)

    Iunes, P.J.

    1990-06-01

    Fission track dating is described, focalizing the problem of the decay constant for spontaneous fission of {sup 238} U and the use of neutron dosimetry in fission track analysis. Experimental procedures using thin films of natural uranium as neutron dosimeters and its results are presented. The author shows a intercomparison between different thin films and between the dosimetry with thin film and other dosimetries. (M.V.M.). 52 refs, 12 figs, 9 tabs.

  20. Groundwater and surface-water interaction, water quality, and processes affecting loads of dissolved solids, selenium, and uranium in Fountain Creek near Pueblo, Colorado, 2012–2014

    Science.gov (United States)

    Arnold, L. Rick; Ortiz, Roderick F.; Brown, Christopher R.; Watts, Kenneth R.

    2016-11-28

    In 2012, the U.S. Geological Survey, in cooperation with the Arkansas River Basin Regional Resource Planning Group, initiated a study of groundwater and surface-water interaction, water quality, and loading of dissolved solids, selenium, and uranium to Fountain Creek near Pueblo, Colorado, to improve understanding of sources and processes affecting loading of these constituents to streams in the Arkansas River Basin. Fourteen monitoring wells were installed in a series of three transects across Fountain Creek near Pueblo, and temporary streamgages were established at each transect to facilitate data collection for the study. Groundwater and surface-water interaction was characterized by using hydrogeologic mapping, groundwater and stream-surface levels, groundwater and stream temperatures, vertical hydraulic-head gradients and ratios of oxygen and hydrogen isotopes in the hyporheic zone, and streamflow mass-balance measurements. Water quality was characterized by collecting periodic samples from groundwater, surface water, and the hyporheic zone for analysis of dissolved solids, selenium, uranium, and other selected constituents and by evaluating the oxidation-reduction condition for each groundwater sample under different hydrologic conditions throughout the study period. Groundwater loads to Fountain Creek and in-stream loads were computed for the study area, and processes affecting loads of dissolved solids, selenium, and uranium were evaluated on the basis of geology, geochemical conditions, land and water use, and evapoconcentration.During the study period, the groundwater-flow system generally contributed flow to Fountain Creek and its hyporheic zone (as a single system) except for the reach between the north and middle transects. However, the direction of flow between the stream, the hyporheic zone, and the near-stream aquifer was variable in response to streamflow and stage. During periods of low streamflow, Fountain Creek generally gained flow from

  1. Current trends with natural language processing.

    Science.gov (United States)

    Rassinoux, A M; Michel, P A; Wagner, J; Baud, R

    1995-01-01

    Natural Language Processing in the medical domain becomes more and more powerful, efficient, and ready to be used in daily practice. The needs for such tools are enormous in the medical field, due to the vast amount of written texts for medical records. In the authors' point of view, the Electronic Patient Record (EPR) is achieved neither with Information Systems of all kinds nor with commercially available word processing systems. Natural Language Processing (NLP) is one dimension of the EPR, as well as Image Processing and Decision Support Systems. Analysis of medical texts to facilitate indexing and retrieval is well known. The need for a generation tool is to produce progress notes from menu driven systems. The computer systems of tomorrow cannot miss any single dimension. Since 1988, we've been developing an NLP system; it is supported by the European program AIM (Advanced Informatics in Medicine) within the GALEN and HELIOS consortium and the CERS (Commission d'Encouragement á la Recherche Scientifique) in Switzerland. The main directions of development are: a medical language analyzer, a language generator, a query processor, and dictionary building tools to support the Medical Linguistic Knowledge Base (MLKB). The knowledge representation schema is essentially based on Sowa's conceptual graphs, and the MLKB is multilingual from its design phase; it currently incorporates the English and the French languages; it will also continue using German. The goal of this demonstration is to provide evidence of what exists today, what will be soon available, and what is planned for the long term. Complete sentences will be processed in real time, and the browsing capabilities of the MLKB will be exercised. In particular, the following features will be presented: Analysis of complete sentences with verbs and relatives, as extracted from clinical narratives, with special attention to the method of "proximity processing" as developed in our group and the rule based

  2. Natural language processing and advanced information management

    Science.gov (United States)

    Hoard, James E.

    1989-01-01

    Integrating diverse information sources and application software in a principled and general manner will require a very capable advanced information management (AIM) system. In particular, such a system will need a comprehensive addressing scheme to locate the material in its docuverse. It will also need a natural language processing (NLP) system of great sophistication. It seems that the NLP system must serve three functions. First, it provides an natural language interface (NLI) for the users. Second, it serves as the core component that understands and makes use of the real-world interpretations (RWIs) contained in the docuverse. Third, it enables the reasoning specialists (RSs) to arrive at conclusions that can be transformed into procedures that will satisfy the users' requests. The best candidate for an intelligent agent that can satisfactorily make use of RSs and transform documents (TDs) appears to be an object oriented data base (OODB). OODBs have, apparently, an inherent capacity to use the large numbers of RSs and TDs that will be required by an AIM system and an inherent capacity to use them in an effective way.

  3. Disseminating natural language processed clinical narratives.

    Science.gov (United States)

    Chen, Elizabeth S; Hripcsak, George; Friedman, Carol

    2006-01-01

    Through Natural Language Processing (NLP) techniques, information can be extracted from clinical narratives for a variety of applications (e.g., patient management). While the complex and nested output of NLP systems can be expressed in standard formats, such as the eXtensible Markup Language (XML), these representations may not be directly suitable for certain end-users or applications. The availability of a âeuro tabular' format that simplifies the content and structure of NLP output may facilitate the dissemination and use by users who are more familiar with common spreadsheet, database, or statistical tools. In this paper, we describe the knowledge-based design of a tabular representation for NLP output and development of a transformation program for the structured output of MedLEE, an NLP system at our institution. Through an evaluation, we found that the simplified tabular format is comparable to existing more complex NLP formats in effectiveness for identifying clinical conditions in narrative reports.

  4. Bicarbonate Elution of Uranium from Amidoxime-Based Polymer Adsorbents for Sequestering Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Horng-Bin [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 USA; Wai, Chien M. [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 USA; Kuo, Li-Jung [Pacific Northwest National Laboratory, Marine Sciences Laboratory, Sequim, Washington 98382 USA; Gill, Gary [Pacific Northwest National Laboratory, Marine Sciences Laboratory, Sequim, Washington 98382 USA; Tian, Guoxin [Lawrence Berkeley National Laboratory, Berkeley, California 94720 USA; Rao, Linfeng [Lawrence Berkeley National Laboratory, Berkeley, California 94720 USA; Das, Sadananda [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA; Mayes, Richard T. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA; Janke, Christopher J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA

    2017-05-02

    Uranium adsorbed on amidoxime-based polyethylene fibers in simulated seawater can be quantitatively eluted using 3 M KHCO3 at 40°C. Thermodynamic calculations are in agreement with the experimental observation that at high bicarbonate concentrations (3 M) uranyl ions bound to amidoxime molecules are converted to uranyl tris-carbonato complex in the aqueous solution. The elution process is basically the reverse reaction of the uranium adsorption process which occurs at a very low bicarbonate concentration (~10-3 M) in seawater. In real seawater experiments, the bicarbonate elution is followed by a NaOH treatment to remove natural organic matter adsorbed on the polymer adsorbent. Using the sequential bicarbonate and NaOH elution, the adsorbent is reusable after rinsing with deionized water and the recycled adsorbent shows no loss of uranium loading capacity based on real seawater experiments.

  5. Theoretical study on electron-phonon coupling factor and electron-ion nonequilibrium process in uranium

    Science.gov (United States)

    Li, Zi; Wang, Cong; Zhao, Jize; Kang, Wei; Zhang, Ping

    2017-02-01

    Rapid laser heating is an important experimental technique to achieve extreme conditions for uranium. Theoretical simulations of the electron-ion nonequilibrium energy relaxation after laser heating usually employ a two-temperature model using the thermal quantities of the electron heat capacity and the electron-phonon coupling factor as input parameters. Based on the first-principles calculations of the electron density of states and Eliashberg function, we theoretically determine the thermal quantities and their dependence on electron temperature and external pressure for uranium and revealed the connection between the thermal quantities and the electron density of states. The electron/ion temperature evolution was examined by employing the two-temperature model with the obtained thermal quantities. The time/temperature at the peak/equilibrium point of the temperature evolution curve was examined for different external pressures and different laser energy densities. We found that the approximation of a linear temperature-dependent electron heat capacity is acceptable at a low energy density, while at a high energy density, the electron temperature dependence of the electron heat capacity and the coupling factor from the first-principles calculations must be considered.

  6. Chelation therapy for treatment of systemic intoxication with uranium: A review.

    Science.gov (United States)

    Šömen Joksić, Agnes; Katz, Sidney A

    2015-01-01

    Elevated levels of naturally occurring uranium have been found in small geographic areas throughout the world. Exposure of the general public to uranium is most often by the ingestion of food and water containing natural uranium from the hydrogeological environment, but this likelihood is remote. However, the risk is increased in regions where uranium is mined, milled, processed and/or fabricated as well as in the vicinity of former battlefields where depleted uranium munitions were deployed. Exposure in such cases is by the inhalation route. Internalized uranium is a long-term hazard the toxicity of which depends upon the dose and the dose rate as well as other parameters such as the chemical form and site of deposition of the uranium and the physiology of the host. The radiological toxicity and the chemical toxicity of uranium and its compounds are responsible for kidney damage and lung cancer. The vulnerable groups are the very young and the very old, individuals predisposed to hypertension or osteoporosis and individuals with chronic kidney disease. Those subject to long-term exposure from internalized uranium are a greater risk for the long-term implications. The accumulation of uranium may be mitigated by decreasing its absorption, distribution and deposition and increasing its elimination with chelating agents. The formation of soluble chelates may enhance the mobilization of uranium deposited in tissue and expedite its transport to and elimination from the renal system. The focus of this review is on the use of chelating agents to enhance decorporation of uranium thereby reducing the risk of intoxication.

  7. Proposal to extract, process and export uranium from Jabiluka orebody No. 2. The Jabiluka proposal - Environmental assessment report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-08-01

    This report assesses the environmental impact of a proposal by Energy Resources of Australia Ltd (ERA) to establish an underground uranium mine with associated infrastructure at the Jabiluka Prospect, approximately 20 km north of Jabiru in the Northern Territory (NT). In accordance with the Environment Protection (Impact of Proposals) Act 1974 (EPIP Act) the Minister for Resources and Energy designated ERA as proponent in relation to prospective decisions to grant approvals for uranium exports from the Jabiluka mine under Regulation 11 of the Customs (Prohibited Exports) Regulations. The report reviews the draft Environmental Impact Statement (draft EIS), public comments on the draft EIS, and the proponent`s responses to these comments in the Supplement to the draft EIS (the draft EIS plus the Supplement constitutes the final EIS). It also relies on information, comments and advice provided by areas within Environment Australia, other relevant Commonwealth agencies, Northern Territory Department of Lands, Planning and Environment (NTDLPE)(through the joint assessment process) and previous studies undertaken in the region

  8. US Department of Energy response to standards for remedial actions at inactive uranium processing sites: Proposed rule

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-29

    The Title I groundwater standards for inactive uranium mill tailings sites, which were promulgated on January 5, 1983, by the US Environmental Protection Agency (EPA) for the Uranium Mill Tailings Remedial Action (UMTRA) Project, were remanded to the EPA on September 3, 1985, by the US Tenth Circuit Court of Appeals. The Court instructed the EPA to compile general groundwater standards for all Title I sites. On September 24, 1987, the EPA published proposed standards (52FR36000-36008) in response to the remand. This report includes an evaluation of the potential effects of the proposed EPA groundwater standards on the UMTRA Project, as well as a discussion of the DOE's position on the proposed standards. The report also contains and appendix which provides supporting information and cost analyses. In order to assess the impacts of the proposed EPA standards, this report summarizes the proposed EPA standards in Section 2.0. The next three sections assess the impacts of the three parts of the EPA standards: Subpart A considers disposal sites; Subpart B is concerned with restoration at processing sites; and Subpart C addresses supplemental standards. Section 6.0 integrates previous sections into a recommendations section. Section 7.0 contains the DOE response to questions posed by the EPA in the preamble to the proposed standards. 6 refs., 5 figs., 3 tabs.

  9. Capital and operating costs of irradiated natural uranium reprocessing plants; Couts d'investissement et d'exploitation des usines de retraitement de l'uranium naturel irradie

    Energy Technology Data Exchange (ETDEWEB)

    Thiriet, L.; Jouannaud, C.; Couture, J.; Duboz, J. [Commissariat a l' Energie Atomique (France). Centre d' Etudes Nucleaires; Oger, C. [Saint Gobain Nucleaire (France)

    1966-07-01

    This paper presents first a method of analysing natural uranium reprocessing plants investment costs (method similar to LANG and BACH well known in the fuel oil industry) and their operating costs (analysed according to their economic type). This method helps establishing standard cost structures for these plants, allowing thus comparisons between existing or planned industrial facilities. It also helps evaluating the foreseeable consequences of technical progress. Some results obtained are given, concerning: the investment costs sensitivity to the various technical parameters defining the fuel and their comparison according to the country or the economic area taken into account. Finally, the influence of the plants size on their investment costs is shown. (author) [French] La communication expose d'abord une methode d'analyse des couts d'investissement des usines de retraitement de l'uranium naturel irradie (inspiree de celles de LANG et de BACH, bien connues dans l'industrie petroliere) et de leurs couts d'exploitation (selon leur nature economique). Cette methode permet d'etablir des structures types de couts de ces usines et de comparer les realisations industrielles et les projets. Elle facilite l'exploration des consequences previsibles du progres technique. On indique un certain nombre de resultats obtenus, concernant la sensibilite des couts d'investissement de ces usines aux differents parametres techniques definissant le combustible et leur confrontation selon les pays ou aires economiques envisages. On montre enfin comment doit pouvoir s'exprimer l'influence de la taille des usines sur leur cout d'investissement. (auteur)

  10. Natural gas conversion process. Sixth quarterly report

    Energy Technology Data Exchange (ETDEWEB)

    1992-12-01

    The experimental apparatus was dismantled and transferred to a laboratory space provided by Lawrence Berkeley Laboratory (LBL) which is already equipped with a high-ventilation fume hood. This will enable us to make tests at higher gas flow rates in a safe environment. Three papers presented at the ACS meeting in San Francisco (Symposium on Natural Gas Upgrading II) April 5--10, 1992 show that the goal of direct catalytic conversion of Methane into heavier Hydrocarbons in a reducing atmosphere is actively pursued in three other different laboratories. There are similarities in their general concept with our own approach, but the temperature range of the experiments reported in these recent papers is much lower and this leads to uneconomic conversion rates. This illustrates the advantages of Methane activation by a Hydrogen plasma to reach commercial conversion rates. A preliminary process flow diagram was established for the Integrated Process, which was outlined in the previous Quarterly Report. The flow diagram also includes all the required auxiliary facilities for product separation and recycle of the unconverted feed as well as for the preparation and compression of the Syngas by-product.

  11. Geochemistry of natural radionuclide in soils surrounding a mining and plant uranium concentration;Geoquimica de radionuclindeos naturais em solos de areas circunvizinhas a uma unidade de mineracao e atividade de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Gildevan Viana, E-mail: gildevan.cardoso@vta.incra.gov.b [Instituto Nacional de Colonizacao e Reforma Agraria (INCRA), Rio de Janeiro, RJ (Brazil); Amaral Sobrinho, Nelson Moura Brasil do; Mazur, Nelson, E-mail: nelmoura@ufrrj.b, E-mail: nelmazur@ufrrj.b [Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropedica, RJ (Brazil). Inst. de Agronomia. Dept. de Solos; Wasserman, Maria Angelica Vergara, E-mail: angelica@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2009-11-15

    The environmental impacts resulting from uranium exploration and processing are to a great extent identical to those caused by extractive mining activities in general. This study aimed to determine the geochemical partitioning of the natural radionuclides {sup 238}U, {sup 226}Ra and {sup 210}Pb in areas surrounding the Uranium Mining and Concentration Plant (URA) of the Brazilian Nuclear Industries S.A., in the uranium deposit region of Lagoa Real, in Caetite, southwestern Bahia state. Representative soil samples of the main regional soil classes were collected from the layer 0-20 cm, in five areas around the URA. The level of total activity and geochemical fractionation (F1 slightly acidic, F2 reducible, F3 oxidisable, F4 alkaline, and F5 residual) were determined for the five areas. The average total radioactivity levels were, in Bq kg{sup -1} soil: 50 for {sup 238}U, 51 for {sup 226}Ra, and 159 for {sup 210}Pb. During the potentially bioavailable phase (F1) 11 % were extracted for {sup 238}U, 13 % for {sup 226}Ra and 3 % for {sup 210}Pb. The bioavailability of {sup 238}U was higher in more acidic soils and the affinity for iron oxides was greater, unlike in the case of {sup 226}Ra, with the greatest bioavailability. {sup 210}Pb was predominantly associated with F5. The high percentage of {sup 238}U, {sup 226}Ra and {sup 210}Pb in the geochemical fraction F5 indicates that the concentrations observed in the five soils are predominantly associated to the parent material of these soils, rather than to an artificial contamination caused by the URA activity. (author)

  12. Importance of Organic Matter-Uranium Biogeochemistry to Uranium Plume Persistence in the Upper Colorado River Basin

    Science.gov (United States)

    Bargar, J.; Janot, N.; Jones, M. E.; Bone, S. E.; Lezama-Pacheco, J.; Fendorf, S. E.; Long, P. E.; Williams, K. H.; Bush, R. P.

    2014-12-01

    Recent evidence suggests that biologically driven redox reactions, fueled by sedimentary lenses enriched in detrital organic matter, play major roles in maintaining the persistent uranium groundwater plume in the subsurface at the U.S. Department of Enery's Rifle, CO field research site. Biogeochemical cycling of C, N, Fe, and S is highly active in these organic-rich naturally reduced zones (NRZs), and uranium is present as U(IV). The speciation of these elements profoundly influences the susceptibility of uranium to be reoxidized and remobiliized and contribute to plume persistence. However, uranim speciation in particular is poorly constrained in these sytems. To better evaluate the importance of NRZs to uranium mobility and plume persistence at the Rifle site, the DOE-BER-funded SLAC SFA team has characterized vertical concentration profiles and speciation of uranium, iron, sulfur, and NOM in well bores at high spatial resolution (4 inch intervals). Up to 95% of the sedimentary uranium pool was found to be concentrated in NRZs, where it occurs dominantly as non-crystalline forms of U(IV). Uranium accumulation and the presence of the short-lived sulfide mackinawite (FeS) at NRZ-aquifer interfaces indicate that NRZs actively exchange solutes with the surrounding aquifer. Moreover, sediment textures indicate that NRZs are likely to be abundant in riparian zones throughout the upper Colorado River basin (U.S.A.), which contains most of the contaminated DOE legacy uranium ore processing sites in the U.S. These results suggest that NRZ-uranium interactions may be important to plume persistence regionally and emphasize the importance of understanding molecular-scale processes.

  13. A natural analogue for copper waste canisters: The copper-uranium mineralised concretions in the Permian mudrocks of south Devon, United Kingdom

    Energy Technology Data Exchange (ETDEWEB)

    Milodowski, A.E.; Styles, M.T.; Hards, V.L. [Natural Environment Research Council (United Kingdom). British Geological Survey

    2000-08-01

    mineralisation and alteration that can be related to the burial and diagenetic history of the Permian strata. The native copper mineralisation exhibits close temporal association with the formation of uraniferous and vanadiferous concretions (known as 'fish-eyes') in the same rocks. Petrographical relationships indicate that both the copper and the 'fish-eye' concretions formed during burial diagenesis but before the maximum compaction of the host mudstone and siltstone. The regional burial history Wessex Basin, indicates that the maximum compaction of the Permian strata would have been achieved by at least the end of the Lower Jurassic (possibly even in the Triassic). Therefore, the native copper mineralisation is older than 176 Ma. The native copper sheets display a complex sequence of alteration and subsequent mineral growth of minerals on their surfaces. The earliest alteration was to copper oxides - principally cuprite with minor tenorite, indicating a change to more oxidising groundwater conditions. The dissolution of native silver and the growth of fringes of copper arsenides followed this. Nickel arsenides and chalcocite, associated with the precipitation of uranium silicates occurred in the later stages of alteration. This suggests a return to a more reducing pore water environment. Again, petrographical relationships indicate that this alteration and subsequent mineralisation is geologically old (i.e. Lower Jurassic or older). Secondary malachite, intimately intergrown copper sulphate and copper oxides, copper chloride, copper-uranium arsenate and uranium vanadates have formed as late-stage alteration products of the native copper and earlier diagenetic cuprite, chalcocite, copper-nickel arsenide and uranium silicate alteration and mineralisation. This latest stage alteration is most probably attributable to near-surface weathering processes. Although the native copper is affected by corrosion, the study has shown that a significant proportion (30

  14. Cosmic secrets fundamental processes of nature

    CERN Document Server

    Schommers, Wolfram

    2009-01-01

    We see objects in front of us, and experience a real material effect when we approach and touch them. Thus, we conclude that all objects are embedded in space and exist objectively. However, such experiences in everyday life cannot be transferred to the atomic level: within standard quantum theory, the material world is still embedded in space, but it no longer has an objective existence. How can objects be embedded in space without existing objectively? This book addresses this and similar issues in an illustrative and non-conventional way. Using up-to-date information, the following basic questions are contemplated: what is a particle, a quantum object; what can we say about the nature of time; how is reality, in particular the cosmos, formed; and, what is the influence of evolution on the discovery of new developments in this field. Like the philosophers Whitehead and Bergson, the primacy of process is advocated: we experience objects - both quantum objects and those we experience in everyday life - at cer...

  15. Uranium removal from aqueous solution by coir pith: equilibrium and kinetic studies.

    Science.gov (United States)

    Parab, Harshala; Joshi, Shreeram; Shenoy, Niyoti; Verma, Rakesh; Lali, Arvind; Sudersanan, M

    2005-07-01

    Basic aspects of uranium adsorption by coir pith have been investigated by batch equilibration. The influence of different experimental parameters such as final solution pH, adsorbent dosage, sorption time, temperature and various concentrations of uranium on uptake were evaluated. Maximum uranium adsorption was observed in the pH range 4.0-6.0. The Freundlich and Langmuir adsorption models were used for the mathematical description of the adsorption equilibrium. The equilibrium data fitted well to both the equilibrium models in the studied concentration range of uranium (200-800 mg/l) and temperatures (305-336 K). The coir pith exhibited the highest uptake capacity for uranium at 317 K, at the final solution pH value of 4.3 and at the initial uranium concentration of 800 mg/l. The kinetics of the adsorption process followed a second-order adsorption. The adsorbent used proved to be suitable for removal of uranium from aqueous solutions. 0.2 N HCl was effective in uranium desorption. The results indicated that the naturally abundant coir pith of otherwise nuisance value exhibited considerable potential for application in removal of uranium from aqueous solution.

  16. Conceptual Process for the Manufacture of Low-Enriched Uranium/Molybdenum Fuel for the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sease, J.D.; Primm, R.T. III; Miller, J.H.

    2007-09-30

    The U.S. nonproliferation policy 'to minimize, and to the extent possible, eliminate the use of HEU in civil nuclear programs throughout the world' has resulted in the conversion (or scheduled conversion) of many of the U.S. research reactors from high-enriched uranium (HEU) to low-enriched uranium (LEU). A foil fuel appears to offer the best option for using a LEU fuel in the High Flux Isotope Reactor (HFIR) without degrading the performance of the reactor. The purpose of this document is to outline a proposed conceptual fabrication process flow sheet for a new, foil-type, 19.75%-enriched fuel for HFIR. The preparation of the flow sheet allows a better understanding of the costs of infrastructure modifications, operating costs, and implementation schedule issues associated with the fabrication of LEU fuel for HFIR. Preparation of a reference flow sheet is one of the first planning steps needed in the development of a new manufacturing capacity for low enriched fuels for U.S. research and test reactors. The flow sheet can be used to develop a work breakdown structure (WBS), a critical path schedule, and identify development needs. The reference flow sheet presented in this report is specifically for production of LEU foil fuel for the HFIR. The need for an overall reference flow sheet for production of fuel for all High Performance Research Reactors (HPRR) has been identified by the national program office. This report could provide a starting point for the development of such a reference flow sheet for a foil-based fuel for all HPRRs. The reference flow sheet presented is based on processes currently being developed by the national program for the LEU foil fuel when available, processes used historically in the manufacture of other nuclear fuels and materials, and processes used in other manufacturing industries producing a product configuration similar to the form required in manufacturing a foil fuel. The processes in the reference flow sheet are

  17. Distribution and potential health risk of groundwater uranium in Korea.

    Science.gov (United States)

    Shin, Woosik; Oh, Jungsun; Choung, Sungwook; Cho, Byong-Wook; Lee, Kwang-Sik; Yun, Uk; Woo, Nam-Chil; Kim, Hyun Koo

    2016-11-01

    Chronic exposure even to extremely low specific radioactivity of natural uranium in groundwater results in kidney problems and potential toxicity in bones. This study was conducted to assess the potential health risk via intake of the groundwater containing uranium, based on the determination of the uranium occurrence in groundwater. The groundwater was investigated from a total of 4140 wells in Korea. Most of the groundwater samples showed neutral pH and (sub-)oxic condition that was influenced by the mixing with shallow groundwater due to long-screened (open) wells. High uranium contents exceeding the WHO guideline level of 30 μg L(-1) were observed in the 160 wells located mainly in the plutonic bedrock regions. The statistical analysis suggested that the uranium component was present in groundwater by desorption and re-dissolution processes. Predominant uranium phases were estimated to uranyl carbonates under the Korean groundwater circumstances. These mobile forms of uranium and oxic condition facilitate the increase of potential health risk downgradient. In particular, long-term intake of groundwater containing >200 μg U L(-1) may induce internal exposure to radiation as well as the effects of chemical toxicity. These high uranium concentrations were found in twenty four sampling wells of rural areas in this study, and they were mainly used for drinking. Therefore, the high-level uranium wells and neighboring areas must be properly managed and monitored to reduce the exposure risk for the residents by drinking groundwater. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Evaluating the effectiveness of dilution of the recovered uranium with depleted uranium and low-enriched uranium to obtain fuel for VVER reactors

    Science.gov (United States)

    Smirnov, A. Yu; Sulaberidze, G. A.; Dudnikov, A. A.; Nevinitsa, V. A.

    2016-09-01

    The possibility of the recovered uranium enrichment in a cascade of gas centrifuges with three feed flows (depleted uranium, low-enriched uranium, recovered uranium) with simultaneous dilution of U-232,234,236 isotopes was shown. A series of numerical experiments were performed for different content of U-235 in low-enriched uranium. It has been demonstrated that the selected combination of diluents can simultaneously reduce the cost of separative work and the consumption of natural uranium, not only with respect to the previously used multi-flow cascade schemes, but also in comparison to the standard cascade for uranium enrichment.

  19. Synthesis and extraction studies with a rationally designed diamide ligand selective to actinide(iv) pertinent to the plutonium uranium redox extraction process.

    Science.gov (United States)

    Sharma, Shikha; Panja, Surajit; Bhattacharyya, Arunasis; Dhami, Prem S; Gandhi, Preetam M; Ghosh, Sunil K

    2016-05-04

    A new class of conformationally constrained oxa-bridged tricyclo-dicarboxamide (OTDA) ligand was rationally designed for the selective extraction of tetravalent actinides pertinent to the Plutonium Uranium Redox EXtraction (PUREX) process. Two of the designed diamide ligands were synthesized and extraction studies were performed for Pu(iv) from HNO3 medium. The mechanism of extraction was investigated by studying various parameters such as feed HNO3, NaNO3 and OTDA concentrations. The nature of the extracted species was found to be [Pu(NO3)4(OTDA)]. One of the OTDA ligands was elaborately tested and showed the selective extraction of Pu(iv) and Np(iv) over other actinide species, viz., U(vi), Np(v), Am(iii), lanthanides and fission products contained in a nuclear waste from the PUREX process. DFT calculations predicted the charge density on each of the coordinating 'O' atoms of OTDA supporting its high Pu(iv) selectivity over other ions studied and also provided the energy optimized structure of OTDA and its Pu(iv) complex.

  20. Release behavior of uranium in uranium mill tailings under environmental conditions.

    Science.gov (United States)

    Liu, Bo; Peng, Tongjiang; Sun, Hongjuan; Yue, Huanjuan

    2017-05-01

    Uranium contamination is observed in sedimentary geochemical environments, but the geochemical and mineralogical processes that control uranium release from sediment are not fully appreciated. Identification of how sediments and water influence the release and migration of uranium is critical to improve the prevention of uranium contamination in soil and groundwater. To understand the process of uranium release and migration from uranium mill tailings under water chemistry conditions, uranium mill tailing samples from northwest China were investigated with batch leaching experiments. Results showed that water played an important role in uranium release from the tailing minerals. The uranium release was clearly influenced by contact time, liquid-solid ratio, particle size, and pH under water chemistry conditions. Longer contact time, higher liquid content, and extreme pH were all not conducive to the stabilization of uranium and accelerated the uranium release from the tailing mineral to the solution. The values of pH were found to significantly influence the extent and mechanisms of uranium release from minerals to water. Uranium release was monitored by a number of interactive processes, including dissolution of uranium-bearing minerals, uranium desorption from mineral surfaces, and formation of aqueous uranium complexes. Considering the impact of contact time, liquid-solid ratio, particle size, and pH on uranium release from uranium mill tailings, reducing the water content, decreasing the porosity of tailing dumps and controlling the pH of tailings were the key factors for prevention and management of environmental pollution in areas near uranium mines. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Decision tree approach to evaluating inactive uranium processing sites for liner requirements

    Energy Technology Data Exchange (ETDEWEB)

    Relyea, J.F.

    1983-03-01

    Recently, concern has been expressed about potential toxic effects of both radon emission and release of toxic elements in leachate from inactive uranium mill tailings piles. Remedial action may be required to meet disposal standards set by the states and the US Environmental Protection Agency (EPA). In some cases, a possible disposal option is the exhumation and reburial (either on site or at a new location) of tailings and reliance on engineered barriers to satisfy the objectives established for remedial actions. Liners under disposal pits are the major engineered barrier for preventing contaminant release to ground and surface water. The purpose of this report is to provide a logical sequence of action, in the form of a decision tree, which could be followed to show whether a selected tailings disposal design meets the objectives for subsurface contaminant release without a liner. This information can be used to determine the need and type of liner for sites exhibiting a potential groundwater problem. The decision tree is based on the capability of hydrologic and mass transport models to predict the movement of water and contaminants with time. The types of modeling capabilities and data needed for those models are described, and the steps required to predict water and contaminant movement are discussed. A demonstration of the decision tree procedure is given to aid the reader in evaluating the need for the adequacy of a liner.

  2. Coarse-to-fine natural language processing

    CERN Document Server

    Petrov, Slav

    2011-01-01

    The impact of computer systems that can understand natural language will be tremendous. To develop this capability we need to be able to automatically and efficiently analyze large amounts of text. Manually devised rules are not sufficient to provide coverage to handle the complex structure of natural language, necessitating systems that can automatically learn from examples. To handle the flexibility of natural language, it has become standard practice to use statistical models, which assign probabilities for example to the different meanings of a word or the plausibility of grammatical const

  3. Estimation of ionizing radiation impact on natural Vicia cracca populations inhabiting areas contaminated with uranium mill tailings and radium production wastes

    Energy Technology Data Exchange (ETDEWEB)

    Evseeva, T.; Majstrenko, T. [Institute of Biology, Komi Scientific Center, Ural Division RAS, Kommunisticheskaya 28, 167982 Syktyvkar (Russian Federation); Geras' kin, S. [Russian Institute of Agricultural Radiology and Agroecology RAAS, 249020 Obninsk, Kaluga region (Russian Federation); Brown, J.E., E-mail: Justin.brown@nrpa.no [Norwegian Radiation Protection Authority, Grini naeringspark 13, 1332 Osteras (Norway); Belykh, E. [Institute of Biology, Komi Scientific Center, Ural Division RAS, Kommunisticheskaya 28, 167982 Syktyvkar (Russian Federation)

    2009-10-01

    Industrial areas in proximity to the Vodny settlement in the Komi Republic, Russia, have been contaminated by uranium mill tailings and radium production wastes. These areas, exhibiting high activity concentrations of naturally occurring radionuclides in soils, constitute a field laboratory where the effects of combined chronic exposures to {alpha}-, {beta}- and {gamma}-emitting radionuclides on natural plant populations can be studied. The aim of the present work was to determine dose-effect relationships and the range of doses that cause biological effects in natural Vicia cracca L. populations inhabiting the study area. The studied plant species is native to the area and is found ubiquitously. Soil and vegetation samples were taken at a reference location and six contaminated sites characterized by distinct floodplain depositional units with different enhanced levels of naturally occurring radionuclides. A large fraction of the dose at the study sites (including the reference location) was attributable to internal irradiation and {sup 226}Ra was found to be an important contributor to this component of dose. The relationship between the frequency of chromosome aberrations in seedlings' root tip cells and the absorbed dose was found to be quadratic. An exponential model provided the best result in describing the empirical dependence between the absorbed dose and both the germination capacity of seeds and the survival rate of sprouts of V. cracca. For V. cracca plants inhabiting areas contaminated with uranium mill tailings and radium production wastes, a weighted absorbed dose of 0.2 Gy (weighting factor for alpha particles = 5) during the vegetation period could be considered to be a level below which no increase in genetic variability and decrease in reproductive capacity might be observed above background.

  4. Estimation of ionizing radiation impact on natural Vicia cracca populations inhabiting areas contaminated with uranium mill tailings and radium production wastes.

    Science.gov (United States)

    Evseeva, T; Majstrenko, T; Geras'kin, S; Brown, J E; Belykh, E

    2009-10-01

    Industrial areas in proximity to the Vodny settlement in the Komi Republic, Russia, have been contaminated by uranium mill tailings and radium production wastes. These areas, exhibiting high activity concentrations of naturally occurring radionuclides in soils, constitute a field laboratory where the effects of combined chronic exposures to alpha-, beta- and gamma-emitting radionuclides on natural plant populations can be studied. The aim of the present work was to determine dose-effect relationships and the range of doses that cause biological effects in natural Vicia cracca L. populations inhabiting the study area. The studied plant species is native to the area and is found ubiquitously. Soil and vegetation samples were taken at a reference location and six contaminated sites characterized by distinct floodplain depositional units with different enhanced levels of naturally occurring radionuclides. A large fraction of the dose at the study sites (including the reference location) was attributable to internal irradiation and (226)Ra was found to be an important contributor to this component of dose. The relationship between the frequency of chromosome aberrations in seedlings' root tip cells and the absorbed dose was found to be quadratic. An exponential model provided the best result in describing the empirical dependence between the absorbed dose and both the germination capacity of seeds and the survival rate of sprouts of V. cracca. For V. cracca plants inhabiting areas contaminated with uranium mill tailings and radium production wastes, a weighted absorbed dose of 0.2 Gy (weighting factor for alpha particles=5) during the vegetation period could be considered to be a level below which no increase in genetic variability and decrease in reproductive capacity might be observed above background.

  5. Uranium Conversion & Enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-06

    The isotopes of uranium that are found in nature, and hence in ‘fresh’ Yellowcake’, are not in relative proportions that are suitable for power or weapons applications. The goal of conversion then is to transform the U3O8 yellowcake into UF6. Conversion and enrichment of uranium is usually required to obtain material with enough 235U to be usable as fuel in a reactor or weapon. The cost, size, and complexity of practical conversion and enrichment facilities aid in nonproliferation by design.

  6. Natural Ecological Processes Affecting the Nulhegan Basin

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is a summary of current understanding of the environmental forces which were responsible for the natural vegetation patterns in northeastem Vermont. This...

  7. SOLVENT EXTRACTION OF URANIUM VALUES

    Science.gov (United States)

    Feder, H.M.; Ader, M.; Ross, L.E.

    1959-02-01

    A process is presented for extracting uranium salt from aqueous acidic solutions by organic solvent extraction. It consists in contacting the uranium bearing solution with a water immiscible dialkylacetamide having at least 8 carbon atoms in the molecule. Mentioned as a preferred extractant is dibutylacetamide. The organic solvent is usually used with a diluent such as kerosene or CCl/sub 4/.

  8. Determination of irradiated reactor uranium in soil samples in Belarus using 236U as irradiated uranium tracer.

    Science.gov (United States)

    Mironov, Vladislav P; Matusevich, Janna L; Kudrjashov, Vladimir P; Boulyga, Sergei F; Becker, J Sabine

    2002-12-01

    This work presents experimental results on the distribution of irradiated reactor uranium from fallout after the accident at Chernobyl Nuclear Power Plant (NPP) in comparison to natural uranium distribution in different soil types. Oxidation processes and vertical migration of irradiated uranium in soils typical of the 30 km relocation area around Chernobyl NPP were studied using 236U as the tracer for irradiated reactor uranium and inductively coupled plasma mass spectrometry as the analytical method for uranium isotope ratio measurements. Measurements of natural uranium yielded significant variations of its concentration in upper soil layers from 2 x 10(-7) g g(-1) to 3.4 x 10(-6) g g(-1). Concentrations of irradiated uranium in the upper 0-10 cm soil layers at the investigated sampling sites varied from 5 x 10(-12) g g(-1) to 2 x 10(-6) g g(-1) depending on the distance from Chernobyl NPP. In the majority of investigated soil profiles 78% to 97% of irradiated "Chernobyl" uranium is still contained in the upper 0-10 cm soil layers. The physical and chemical characteristics of the soil do not have any significant influence on processes of fuel particle destruction. Results obtained using carbonate leaching of 236U confirmed that more than 60% of irradiated "Chernobyl" uranium is still in a tetravalent form, ie. it is included in the fuel matrix (non-oxidized fuel UO2). The average value of the destruction rate of fuel particles determined for the Western radioactive trace (k = 0.030 +/- 0.005 yr(-1)) and for the Northern radioactive trace (k = 0.035 + 0.009 yr(-1)) coincide within experimental errors. Use of leaching of fission products in comparison to leaching of uranium for study of the destruction rate of fuel particles yielded poor coincidence due to the fact that use of fission products does not take into account differences in the chemical properties of fission products and fuel matrix (uranium).

  9. Sensitive Determination of Uranium in Natural Waters Using UV-Vis Spectrometry After Preconcentration by Ion-Imprinted Polymer-Ternary Complexes.

    Science.gov (United States)

    Bicim, Tulin; Yaman, Mehmet

    2016-07-01

    The main purpose of this study was to achieve a substantial increase in the sensitivity of the uranium determination using UV-Vis spectrometry. To achieve this goal, ion-imprinted polymers were prepared for the uranyl (imprint) ion by the formation of a ternary (salicylaldoxime and 4-vinylpyridine) complex in 2-methoxy ethanol (porogen) following copolymerization with methacrylic acid. The synthesized polymers were characterized by FTIR analysis and thermogravimetric analysis. In the preconcentration step, the optimal pH was determined to be between values of 3.5 and 6.5. The adsorbed UO2(2+) was completely eluted by 10 mL of 3.0 mol L(-1) HClO4. The developed method was applied to uranium (VI) determination in natural water samples. By using the initial volume of 500 mL and final volume of 5 mL, a concentration of 1 μg L(-1) can be determined by applying the developed method in this study.

  10. Absorbed dose rate due to intake of natural radionuclides by Tilapia fish (Tilapia nilotica, Linnaeus, 1758) estimated near uranium anomaly at Santa Quiteria, Ceara, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de [Industrias Nucleares do Brasil S.A. (INB), Pocos de Caldas, MG (Brazil). Coordenacao de Protecao Radiologica. Unidade de Tratamento de Minerios], E-mail: wspereira@inb.gov.br; Kelecom, Alphonse [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Programa de Pos-graduacao em Ciencia Ambiental; Py Junior, Delcy de Azevedo [Industrias Nucleares do Brasil S.A. (INB), Caetite, BA (Brazil). Coordenacao de Protecao Radiologica. Unidade de Concentrado de Uranio], E-mail: Delcy@inb.gov.br

    2007-07-01

    The uranium mining at Santa Quiteria (Santa Quiteria Unit - USQ) is in its environmental licensing phase. Aiming to estimate the radiological environmental impact of the USQ, a monitoring program is underway. However, radioprotection of biota is not explicitly mentioned in Brazilian norms. In order to preserve the biota of the deleterious effects from radiation and to behave in a pro-active way as expected by licensing organs, the present work aims to use an environmental protection methodology, based on the calculation of absorbed dose rate in biota. Thus, selected biomarker was the fish tilapia (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). Since there are no exposition limits for biota, in Brazil, the value proposed by the Department of Energy (DOE) of the United States of 3.5 x 10{sup 3} {mu}Gy/y has been used. The derived absorbed dose rate calculated for tilapia was 2.76 x 10{sup 0} {mu}Gy/y, that is less than 0.1 % of the limit established by DOE. The critical radionuclide was U-238, with 99% of the absorbed dose rate. This value of 0.1% of the limit allows to state that in pre-operational conditions analyzed natural radionuclides do not represent a radiological problem to the biota. (author)

  11. Scouring Process of Natural Color Cotton Products

    Institute of Scientific and Technical Information of China (English)

    XU Wei

    2002-01-01

    In order to improve the absorbency of color cotton products, alkali and pectase scouring processes under different conditions were tested, by comparing the actual results of two different scouring processes. It was considered that the pectase scouring process more suits color cotton products.

  12. Semantic structures advances in natural language processing

    CERN Document Server

    Waltz, David L

    2014-01-01

    Natural language understanding is central to the goals of artificial intelligence. Any truly intelligent machine must be capable of carrying on a conversation: dialogue, particularly clarification dialogue, is essential if we are to avoid disasters caused by the misunderstanding of the intelligent interactive systems of the future. This book is an interim report on the grand enterprise of devising a machine that can use natural language as fluently as a human. What has really been achieved since this goal was first formulated in Turing's famous test? What obstacles still need to be overcome?

  13. Kinetics of Uranium Extraction from Uranium Tailings by Oxidative Leaching

    Science.gov (United States)

    Zhang, Biao; Li, Mi; Zhang, Xiaowen; Huang, Jing

    2016-07-01

    Extraction of uranium from uranium tailings by oxidative leaching with hydrogen peroxide (H2O2) was studied. The effects of various extraction factors were investigated to optimize the dissolution conditions, as well as to determine the leaching kinetic parameters. The behavior of H2O2 in the leaching process was determined through scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and x-ray diffraction analysis of leaching residues. Results suggest that H2O2 can significantly improve uranium extraction by decomposing the complex gangue structures in uranium tailings and by enhancing the reaction rate between uranium phases and the leaching agent. The extraction kinetics expression was changed from 1 - 3(1 - α)2/3 + 2(1 - α) = K 0(H2SO4)-0.14903(S/L)-1.80435( R o)0.20023 e -1670.93/T t ( t ≥ 5) to 1 - 3(1 - α)2/3 + 2(1 - α) = K 0(H2SO4)0.01382(S/L)-1.83275( R o)0.25763 e -1654.59/T t ( t ≥ 5) by the addition of H2O2 in the leaching process. The use of H2O2 in uranium leaching may help in extracting uranium more efficiently and rapidly from low-uranium-containing ores or tailings.

  14. A study of phase transformations processes in 0,5 to 4% mo uranium-molybdenum alloys; Etude des processus des transformations dans les alliages uranium-molybdene de teneur 0,5 a 4% en poids de molybdene

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-06-15

    Isothermal and continuous cooling transformations process have been established on uranium-molybdenum alloys containing 0,5 to 4 w% Mo. Transformations process of the {beta} and {gamma} solid solutions are described. These processes depend upon molybdenum concentration. Out of the {beta} solid solution phase appears an eutectoid decomposition of {beta} to ({alpha} + {gamma}) or the formation of a martensitic phase {alpha}''. The {gamma} solid solution shows a decomposition of {gamma} to ({alpha} + {gamma}) or ({alpha} + {gamma}'), or a formation of martensitic phases a' or a'{sub b}. The U-Mo equilibrium diagram is discussed, particularly in low concentrations zones. Limits between domains ({alpha} + {gamma}) and ({beta} + {gamma}), ({beta} + {gamma}) and {gamma}, ({beta} + {gamma}) and {beta}, have been determined. (author) [French] Les processus des transformations isothermes, et au cours de refroidissements continus ont ete etablis sur les alliages uranium-molybdene de 0,5 a 4 % en poids de Mo. Ceci a permis de mettre en evidence les processus des transformations de solutions solides {beta} et {gamma}, differents suivant la teneur en molybdene de l'alliage. Dans le premier cas il y a decomposition eutectoide de {beta} en ({alpha} + {gamma}) ou formations d'une phase martensitique {alpha}''. Dans le second cas il y a decomposition de {gamma} soit en ({alpha} + {gamma}) soit en ({alpha} + {gamma}') suivant la temperature, ou bien formation des phases martensitiques {alpha}' ou {alpha}'{sub b}. Le diagramme d'equilibre, uranium-molybdene est sujet a de nombreuses controverses, en particulier dans la zone des faibles concentrations. Les limites entre les domaines ({alpha} + {gamma}) et ({beta} + {gamma}), ({beta} + {gamma}) et {gamma}, ({beta} + {gamma}) et {beta}, ont ete determinees. (auteur)

  15. 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

    controlled field conditions. In the third and fourth year a suite of larger field studies were conducted. For these studies, the uranium flux sensor was used with uranium speciation measurements and molecular-biological tools to characterize microbial community and active biomass at synonymous wells distributed in a large grid. These field efforts quantified spatial changes in uranium flux and field-scale rates of uranium attenuation (ambient and stimulated), uranium stability, and quantitatively assessed how fluxes and effective reaction rates were coupled to spatial variations in microbial community and active biomass. Analyses of data from these field experiments were used to generate estimates of Monod kinetic parameters that are ‘effective’ in nature and optimal for modeling uranium fate and transport at the field-scale. This project provided the opportunity to develop the first sensor that provides direct measures of both uranium (VI) and groundwater flux. A multidisciplinary team was assembled to include two geochemists, a microbiologist, and two quantitative contaminant hydrologists. Now that the project is complete, the sensor can be deployed at DOE sites to evaluate field-scale uranium attenuation, source behavior, the efficacy of remediation, and off-site risk. Because the sensor requires no power, it can be deployed at remote sites for periods of days to months. The fundamental science derived from this project can be used to advance the development of predictive models for various transport and attenuation processes in aquifers. Proper development of these models is critical for long-term stewardship of contaminated sites in the context of predicting uranium source behavior, remediation performance, and off-site risk.

  16. Uranium Recovery from Uranium Mineral Bio-Heap Residues with Microbial Column Leaching Process%微生物柱浸法从铀矿石堆浸尾渣中回收铀的研究

    Institute of Scientific and Technical Information of China (English)

    李江; 刘亚洁; 车江华; 饶军

    2012-01-01

    Column bio-leaching tests under different spraying conditions on the uranium mineral bio-heap residues were conducted with bio-heap leaching process. The uranium content of the residues was 0. 014%. The results show that the leaching rate is 50% after a leaching period of four months with ratio of liquid to solid of L 74 and one spray for two-days, while the leaching rate is 28- 6% with ratio of liquid to solid of 0. 94 and one spray for four-days. This leaching process with small and interval spray has the advantages of low cost, efficient uranium recovery from the bio-heap residues and less environmental pollution.%对广东某铀矿微生物堆浸后品位为0.014%的尾渣进行了不同喷淋条件下的微生物柱浸试验.结果表明,浸出周期4个月,在2天喷淋1次条件下,液固比为1.74,渣计浸出率50%;在4天喷淋1次条件下,液固比为0.94,渣计浸出率28.6%.小喷淋量、间歇式喷淋的微生物浸出工艺,成本低,能有效回收堆浸尾渣中的铀资源,同时减少环境污染.

  17. INTRAVAL phase 2, test case 8. Alligator Rivers Natural Analogue. Modelling of uranium transport in the weathered zone at Koongarra, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Hassanizadeh, S.M.; Van de Weerd, H.; Richardson-Van der Poel, M.A. [National Inst. of Public Health and Environmental Protection RIVM, Bilthoven (Netherlands)

    1993-01-01

    Preliminary results of modelling of the dispersion of uranium in the weathered and transition zones are given. In the course of the Alligator Rivers Analogue Project (ARAP) more insight was gained about the formation of the dispersion fan and about the hydrology at Koongarra. The here applied transport modelling strategy takes into account those results. First, a general explanation of Natural Analogue is given, next to a brief description of the ARAP test case, carried out within the INTRAVAL phase 2. INTRAVAL is an international project concerned with the use of mathematical models for predicting the potential transport of radioactive solutes in the geosphere. Following is the analysis of chemical data, necessary for the choice of the modelling approach, for estimation of model inputs and for testing model results. Subsequently, the modelling strategy is expounded and a description is given of METROPOL, the transport code, used for modelling. 11 figs., 2 tabs., 1 appendix, 17 refs.

  18. Video processing of remote sensor data applied to uranium exploration in Wyoming. [Roll-front U deposits

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, R.A.; Marrs, R.W.; Crockell, F.

    1979-06-30

    LANDSAT satellite imagery and aerial photography can be used to map areas of altered sandstone associated with roll-front uranium deposits. Image data must be enhanced so that alteration spectral contrasts can be seen, and video image processing is a fast, low-cost, and efficient tool. For LANDSAT data, the 7/4 ratio produces the best enhancement of altered sandstone. The 6/4 ratio is most effective for color infrared aerial photography. Geochemical and mineralogical associations occur in unaltered, altered, and ore roll-front zones. Samples from Pumpkin Buttes show that iron is the primary coloring agent which makes alteration visually detectable. Eh and pH changes associated with passage of a roll front cause oxidation of magnetite and pyrite to hematite, goethite, and limonite in the host sandstone, thereby producing the alteration. Statistical analysis show that the detectability of geochemical and color zonation in host sands is weakened by soil-forming processes. Alteration can only be mapped in areas of thin soil cover and moderate to sparse vegetative cover.

  19. The terrestrial uranium isotope cycle.

    Science.gov (United States)

    Andersen, Morten B; Elliott, Tim; Freymuth, Heye; Sims, Kenneth W W; Niu, Yaoling; Kelley, Katherine A

    2015-01-15

    Changing conditions on the Earth's surface can have a remarkable influence on the composition of its overwhelmingly more massive interior. The global distribution of uranium is a notable example. In early Earth history, the continental crust was enriched in uranium. Yet after the initial rise in atmospheric oxygen, about 2.4 billion years ago, the aqueous mobility of oxidized uranium resulted in its significant transport to the oceans and, ultimately, by means of subduction, back to the mantle. Here we explore the isotopic characteristics of this global uranium cycle. We show that the subducted flux of uranium is isotopically distinct, with high (238)U/(235)U ratios, as a result of alteration processes at the bottom of an oxic ocean. We also find that mid-ocean-ridge basalts (MORBs) have (238)U/(235)U ratios higher than does the bulk Earth, confirming the widespread pollution of the upper mantle with this recycled uranium. Although many ocean island basalts (OIBs) are argued to contain a recycled component, their uranium isotopic compositions do not differ from those of the bulk Earth. Because subducted uranium was probably isotopically unfractionated before full oceanic oxidation, about 600 million years ago, this observation reflects the greater antiquity of OIB sources. Elemental and isotope systematics of uranium in OIBs are strikingly consistent with previous OIB lead model ages, indicating that these mantle reservoirs formed between 2.4 and 1.8 billion years ago. In contrast, the uranium isotopic composition of MORB requires the convective stirring of recycled uranium throughout the upper mantle within the past 600 million years.

  20. Synthesis of Uranium nitride powders using metal uranium powders

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jae Ho; Kim, Dong Joo; Oh, Jang Soo; Rhee, Young Woo; Kim, Jong Hun; Kim, Keon Sik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-10-15

    Uranium nitride (UN) is a potential fuel material for advanced nuclear reactors because of their high fuel density, high thermal conductivity, high melting temperature, and considerable breeding capability in LWRs. Uranium nitride powders can be fabricated by a carbothermic reduction of the oxide powders, or the nitriding of metal uranium. The carbothermic reduction has an advantage in the production of fine powders. However it has many drawbacks such as an inevitable engagement of impurities, process burden, and difficulties in reusing of expensive N{sup 15} gas. Manufacturing concerns issued in the carbothermic reduction process can be solved by changing the starting materials from oxide powder to metals. However, in nitriding process of metal, it is difficult to obtain fine nitride powders because metal uranium is usually fabricated in the form of bulk ingots. In this study, a simple reaction method was tested to fabricate uranium nitride powders directly from uranium metal powders. We fabricated uranium metal spherical powder and flake using a centrifugal atomization method. The nitride powders were obtained by thermal treating those metal particles under nitrogen containing gas. We investigated the phase and morphology evolutions of powders during the nitriding process. A phase analysis of nitride powders was also a part of the present work.

  1. Uranium geochemistry in a calcareous peat: mineral-organic-microorganisms interactions and implications on uranium mobility in a contaminated soil; Geochimie de l'uranium dans une tourbe calcaire: interactions mineral - organique - micro-organismes et implications sur la mobilite de l'uranium dans un sol contamine

    Energy Technology Data Exchange (ETDEWEB)

    Phrommavanh, V.; Descostes, M.; L' Orphelin, J.M.; Beaucaire, C. [CEA Saclay, DEN/DPC/SECR/Laboratoire de Mesure et Modelisation de la Migration des Radionucleides, 91 - Gif-sur-Yvette (France); Gaudet, J.P. [LTHE/ENSHMG, 38 - St Martin d' Heres (France)

    2009-07-01

    The authors discuss the different approaches and techniques which have been implemented to study the behaviour of uranium in an as complex medium as a natural peat, in this case, a calcareous peat located on an old industrial site which was dedicated to uranium processing and which is now being decontaminated. They report and comment a chemical and mineralogical characterization of this peat, its hydrochemical characterization, and a microbial flora characterization

  2. The chemical industry of uranium in France; L'industrie chimique de l'uranium en France

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmidt, B. [Commissariat a l' Energie Atomique, Paris (France). Centre d' Etudes Nucleaires

    1955-07-01

    The actual CEA program is concerned with the construction of two large graphite reactors, each of those containing at least one hundred tons of uranium metal with nuclear purity. The uranium for these two reactors will be regularly supplied by new resources discovered in France and Madagascar in the last five years. The working and treatment of such ore have led to the creation of an important french industry of which the general outline and principle are described. The operated ores have got different natures and concentration, individual characteristics are described for the main ores.The most high-grade ore are transported to a central plant in Bouchet near Paris; the low-grade ore are concentrated by physical methods or chemical processes of which principles and economy are studied with constancy. The acid processes are the only used until now, although the carbonated alkaline processes has been studied in France. The next following steps after the acid process until the obtention of uranium rich concentrate are described. The purification steps of uranium compounds to nuclear purity material are described as well as the steps to elaborate metal of which the purity grade will be specify. Finally, the economic aspects of uranium production difficulty will be considered in relation with technical progresses which we can expect to achieve in the future. (M.P.)

  3. Uranium recovery from slags of metallic uranium; Recuperacao de uranio em escorias de uranio metalico

    Energy Technology Data Exchange (ETDEWEB)

    Fornarolo, F.; Frajndlich, E.U.C.; Durazzo, M. [Instituto de Pesquisas Energeticas e Nucleares (CNEN/IPEN-SP), Sao Paulo, SP (Brazil). Centro de Combustiveis Nucleares], e-mail: ffornar@ipen.br

    2006-07-01

    The Center of the Nuclear Fuel of the Institute of Nuclear Energy Research - IPEN finished the program of attainment of fuel development for research reactors the base of Uranium Scilicet (U{sub 3} Si{sub 2}) from Hexafluoride of Uranium (UF{sub 6}) with enrichment 20% in weight of {sup 235}U. In the process of attainment of the league of U 3 Si 2 we have as Uranium intermediate product the metallic one whose attainment generates a slag contend Uranium. The present work shows the results gotten in the process of recovery of Uranium in slags of calcined slags of Uranium metallic. Uranium the metallic one is unstable, pyrophoricity and extremely reactive, whereas the U{sub 3}O{sub 8} is a steady oxide of low chemical reactivity, what it justifies the process of calcination of slags of Uranium metallic. The calcination of the Uranium slag of the metallic one in oxygen presence reduces Uranium metallic the U{sub 3}O{sub 8}. Experiments had been developed varying it of acid for Uranium control and excess, nitric molar concentration gram with regard to the stoichiometric leaching reaction of temperature of the leaching process. The 96,0% income proves the viability of the recovery process of slags of Uranium metallic, adopting it previous calcination of these slags in nitric way with low acid concentration and low temperature of leaching. (author)

  4. Natural Language Processing: Word Recognition without Segmentation.

    Science.gov (United States)

    Saeed, Khalid; Dardzinska, Agnieszka

    2001-01-01

    Discussion of automatic recognition of hand and machine-written cursive text using the Arabic alphabet focuses on an algorithm for word recognition. Describes results of testing words for recognition without segmentation and considers the algorithms' use for words of different fonts and for processing whole sentences. (Author/LRW)

  5. Using Card Games to Simulate the Process of Natural Selection

    Science.gov (United States)

    Grilliot, Matthew E.; Harden, Siegfried

    2014-01-01

    In 1858, Darwin published "On the Origin of Species by Means of Natural Selection." His explanation of evolution by natural selection has become the unifying theme of biology. We have found that many students do not fully comprehend the process of evolution by natural selection. We discuss a few simple games that incorporate hands-on…

  6. Meeting of the French geological society - Uranium: geology, geophysics, chemistry. Book of abstracts; Reunion de la Societe Geologique de France - Uranium: geologie, geophysique, chimie. Recueil des resumes

    Energy Technology Data Exchange (ETDEWEB)

    Zakari, A.A.; Mima, S.; Bidaud, A.; Criqui, P.; Menanteau, P.; David, S.; Pagel, M.; Chagnes, A.; Cote, G.; Courtaud, B.; Thiry, J.; Miehe, J.M.; Gilbert, F.; Cuney, M.; Bruneton, P.; Ewington, D.; Vautrin-Ul, C.; Cannizzo, C.; Betelu, S.; Chausse, A.; Ly, J.; Bourgeois, D.; Maynadie, J.; Meyer, D.; Clavier, N.; Costin, D.T.; Cretaz, F.; Szenknect, S.; Ravaux, J.; Poinssot, C.; Dacheux, N.; Durupt, N.; Blanvillain, J.J.; Geffroy, F.; Aparicio, B.; Dubessy, J.; Nguyen-Trung, C.; Robert, P.; Uri, F.; Beaufort, D.; Lescuyer, J.L.; Morichon, E.; Allard, T.; Milesi, J.P.; Richard, A.; Rozsypal, C.; Mercadier, J.; Banks, D.A.; Boiron, M.C.; Cathelineau, M.; Dardel, J.; Billon, S.; Patrier, P.; Wattinne, A.; Vanderhaeghe, O.; Fabre, C.; Castillo, M.; Salvi, S.; Beziat, D.; Williams-Jones, A.E.; Trap, P.; Durand, C.; Goncalves, P.; Marquer, D.; Feybesse, J.L.; Richard, Y.; Orberger, B.; Hofmann, A.; Megneng, M.; Orberger, B.; Bouttemy, M.; Vigneron, J.; Etcheberry, A.; Perdicakis, M.; Prignon, N.; Toe, W.; Andre-Mayer, A.S.; Eglinger, A.; Jordaan, T.; Hocquet, S.; Ledru, P.; Selezneva, V.; Vendryes, G.; Lach, P.; Cuney, M.; Mercadier, J.; Brouand, M.; Duran, C.; Seydoux-Guillaume, A.M.; Bingen, B.; Parseval, P. de; Guillaume, D.; Bosse, V.; Paquette, J.L.; Ingrin, J.; Montel, J.M.; Giot, R.; Maucotel, F.; Hubert, S.; Gautheron, C.; Tassan-Got, L.; Pagel, M.; Barbarand, J.; Cuney, M.; Lach, P.; Bonhoure, J.; Leisen, M.; Kister, P.; Salaun, A.; Villemant, B.; Gerard, M.; Komorowski, J.C.; Michel, A.; Riegler, T.; Tartese, R.; Boulvais, P.; Poujols, M.; Gloaguen, E.; Mazzanti, M.; Mougel, V.; Nocton, G.; Biswas, B.; Pecaut, J.; Othmane, G.; Menguy, N.; Vercouter, T.; Morin, G.; Galoisy, L.; Calas, G.; Fayek, M.

    2010-11-15

    This document brings together the abstracts of the 39 presentations given at this meeting days on uranium, organized by the French geological society, and dealing with: 1 - Prospective study of the electronuclear technological transition; 2 - The front-end of the nuclear cycle: from the molecule to the process; 3 - Geophysics: recent changes; 4 - Use of well logging in uranium exploration; 5 - Genetical classification of thorium deposits; 6 - Genetical nomenclature of uranium sources; 7 - Uranium deposits linked to a Proterozoic discordance - retrospective; 8 - The use of spectral analysis techniques in uranium exploration: real-time mapping of clay alteration features; 9 - Development of functionalized silk-screened carbon electrodes for the analysis of uranium trace amounts; 10 - Study of the actinides solvation sphere in organic environment; 11 - Thermodynamic of uraniferous phases of interest for the nuclear cycle; 12 - Heap leaching of marginal minerals at Somair: from lab studies to the production of 700 t of uranium/year; 13 - Agglomeration phenomenology and role of iron in uranium heap leaching; 14 - Chloride uranyl complexes up to 300 deg. C along the saturation vapour curve: Raman spectroscopy analysis and metallogenic consequences; 15 - Weathering systems in the Shea Creek deposit (Athabasca, Canada): vertical variability of argillaceous weathering; 16 - Weathering systems in the Shea Creek deposit (Athabasca, Canada): contribution of irradiation defects in clays to the tracing of past uranium migrations; 17 - Uranium concentrations in mineralizing fluids of the Athabasca basin: analytical and experimental approach; 18 - Paleo-surfaces and metallic rooting: the autochthonous uranium of pre-Athabasca paleo-alterites, Canada; 19 - Distribution of argillaceous parageneses in the Imouraren deposit - Niger; 20 - Heat flux and radioelements concentration (U, Th, K) of precambrian basements: implications in terms of crust growth mechanisms, paleo

  7. Improved and new uses of natural radioactivity in mineral exploration and processing

    NARCIS (Netherlands)

    de Meijer, R.J.; Stapel, C.; Jones, D.G.; Roberts, P.D.; Rozendaal, A.; Macdonald, W.G.

    1997-01-01

    Measurement of natural radioactivity has been used in both a qualitative and a quantitative way in mineral exploration, particularly in the search for uranium. In the last five years, the Kernfysisch Versneller Instituut (KVI) and British Geological Survey (BGS) have designed, built and tested a new

  8. Mathematical simulation of the process of condensing natural gas

    Directory of Open Access Journals (Sweden)

    Tastandieva G.M.

    2015-01-01

    Full Text Available Presents a two-dimensional unsteady model of heat transfer in terms of condensation of natural gas at low temperatures. Performed calculations of the process heat and mass transfer of liquefied natural gas (LNG storage tanks of cylindrical shape. The influence of model parameters on the nature of heat transfer. Defined temperature regimes eliminate evaporation by cooling liquefied natural gas. The obtained dependence of the mass flow rate of vapor condensation gas temperature. Identified the possibility of regulating the process of “cooling down” liquefied natural gas in terms of its partial evaporation with low cost energy.

  9. Idaho National Engineering and Environmental Laboratory Site Report on the Production and Use of Recycled Uranium

    Energy Technology Data Exchange (ETDEWEB)

    L. C. Lewis; D. C. Barg; C. L. Bendixsen; J. P. Henscheid; D. R. Wenzel; B. L. Denning

    2000-09-01

    Recent allegations regarding radiation exposure to radionuclides present in recycled uranium sent to the gaseous diffusion plants prompted the Department of Energy to undertake a system-wide study of recycled uranium. Of particular interest, were the flowpaths from site to site operations and facilities in which exposure to plutonium, neptunium and technetium could occur, and to the workers that could receive a significant radiation dose from handling recycled uranium. The Idaho National Engineering and Environmental Laboratory site report is primarily concerned with two locations. Recycled uranium was produced at the Idaho Chemical Processing Plant where highly enriched uranium was recovered from spent fuel. The other facility is the Specific Manufacturing Facility (SMC) where recycled, depleted uranium is manufactured into shapes for use by their customer. The SMC is a manufacturing facility that uses depleted uranium metal as a raw material that is then rolled and cut into shapes. There are no chemical processes that might concentrate any of the radioactive contaminant species. Recyclable depleted uranium from the SMC facility is sent to a private metallurgical facility for recasting. Analyses on the recast billets indicate that there is no change in the concentrations of transuranics as a result of the recasting process. The Idaho Chemical Processing Plant was built to recover high-enriched uranium from spent nuclear fuel from test reactors. The facility processed diverse types of fuel which required uniquely different fuel dissolution processes. The dissolved fuel was passed through three cycles of solvent extraction which resulted in a concentrated uranyl nitrate product. For the first half of the operating period, the uranium was shipped as the concentrated solution. For the second half of the operating period the uranium solution was thermally converted to granular, uranium trioxide solids. The dose reconstruction project has evaluated work exposure and

  10. Domestic utility attitudes toward foreign uranium supply

    Energy Technology Data Exchange (ETDEWEB)

    1981-06-01

    The current embargo on the enrichment of foreign-origin uranium for use in domestic utilization facilities is scheduled to be removed in 1984. The pending removal of this embargo, complicated by a depressed worldwide market for uranium, has prompted consideration of a new or extended embargo within the US Government. As part of its on-going data collection activities, Nuclear Resources International (NRI) has surveyed 50 domestic utility/utility holding companies (representing 60 lead operator-utilities) on their foreign uranium purchase strategies and intentions. The most recent survey was conducted in early May 1981. A number of qualitative observations were made during the course of the survey. The major observations are: domestic utility views toward foreign uranium purchase are dynamic; all but three utilities had some considered foreign purchase strategy; some utilities have problems with buying foreign uranium from particular countries; an inducement is often required by some utilities to buy foreign uranium; opinions varied among utilities concerning the viability of the domestic uranium industry; and many utilities could have foreign uranium fed through their domestic uranium contracts (indirect purchases). The above observations are expanded in the final section of the report. However, it should be noted that two of the observations are particularly important and should be seriously considered in formulation of foreign uranium import restrictions. These important observations are the dynamic nature of the subject matter and the potentially large and imbalanced effect the indirect purchases could have on utility foreign uranium procurement.

  11. Overland erosion of uranium-mill-tailings impoundments: physical processes and computational methods

    Energy Technology Data Exchange (ETDEWEB)

    Walters, M.H.

    1983-03-01

    The surface runoff and erosional processes of watersheds caused by rainfall-runoff are reviewed. Soil properties, topography, and rainstorm distribution are discussed with respect to their effects on soil erosion. The effects of climate and vegetation are briefly presented. Regression models and physical process simulation models are reviewed.

  12. Mathematical simulation of the process of condensing natural gas

    OpenAIRE

    Tastandieva G.M.

    2015-01-01

    Presents a two-dimensional unsteady model of heat transfer in terms of condensation of natural gas at low temperatures. Performed calculations of the process heat and mass transfer of liquefied natural gas (LNG) storage tanks of cylindrical shape. The influence of model parameters on the nature of heat transfer. Defined temperature regimes eliminate evaporation by cooling liquefied natural gas. The obtained dependence of the mass flow rate of vapor condensation gas temperature. Identified the...

  13. SSH gene expression profile of Eisenia andrei exposed in situ to a naturally contaminated soil from an abandoned uranium mine.

    Science.gov (United States)

    Lourenço, Joana; Pereira, Ruth; Gonçalves, Fernando; Mendo, Sónia

    2013-02-01

    The effects of the exposure of earthworms (Eisenia andrei) to contaminated soil from an abandoned uranium mine, were assessed through gene expression profile evaluation by Suppression Subtractive Hybridization (SSH). Organisms were exposed in situ for 56 days, in containers placed both in a contaminated and in a non-contaminated site (reference). Organisms were sampled after 14 and 56 days of exposure. Results showed that the main physiological functions affected by the exposure to metals and radionuclides were: metabolism, oxireductase activity, redox homeostasis and response to chemical stimulus and stress. The relative expression of NADH dehydrogenase subunit 1 and elongation factor 1 alpha was also affected, since the genes encoding these enzymes were significantly up and down-regulated, after 14 and 56 days of exposure, respectively. Also, an EST with homology for SET oncogene was found to be up-regulated. To the best of our knowledge, this is the first time that this gene was identified in earthworms and thus, further studies are required, to clarify its involvement in the toxicity of metals and radionuclides. Considering the results herein presented, gene expression profiling proved to be a very useful tool to detect earthworms underlying responses to metals and radionuclides exposure, pointing out for the detection and development of potential new biomarkers.

  14. Bomb reduction of uranium tetrafluoride. Part II: Influence of the addition elements in the reduction process; Reduccion del tetrafluoruro de uranio en bomba cerrada. Parte II: Influencia de elementos de adicion en la reducion

    Energy Technology Data Exchange (ETDEWEB)

    Anca Abati, R.; Lopez Rodriguez, M.

    1962-07-01

    This work shows the influence of uranium oxide and uranyl fluoride in the reduction of uranium with Ca and Mg. These additions are more harmful when using smaller bombs. The uranyl fluoride has influence in the reduction process; the curves yield-concentration shows two regions depending upon the salt concentration. The behaviour of this addition in these regions can be explained following the different decompositions that can take place during the reduction process. (Author) 9 refs.

  15. Process for Transition of Uranium Mill Tailings Radiation Control Act Title II Disposal Sites to the U.S. Department of Energy Office of Legacy Management for Long-Term Surveillance and Maintenance

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-03-01

    This document presents guidance for implementing the process that the U.S. Department of Energy (DOE) Office of Legacy Management (LM) will use for assuming perpetual responsibility for a closed uranium mill tailings site. The transition process specifically addresses sites regulated under Title II of the Uranium Mill Tailings Radiation Control Act (UMTRCA) but is applicable in principle to the transition of sites under other regulatory structures, such as the Formerly Utilized Sites Remedial Action Program.

  16. Towards a genetic classification of uranium deposits; Vers une classification genetique des gisements d'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Cuney, M. [G2R, Nancy Universite, CNRS, CREGU, 54 - Vandoeuvre les Nancy (France)

    2009-07-01

    As the IAEA's uranium deposit classification is based on the deposit nature and morphology, some deposits which have been formed by very different genetic processes and located in very different geological environments, are grouped according to this classification. In order to build up a reliable genetic classification based on the mechanism at the origin of the formation of the deposit, the author presents the five main categories according to which uranium deposits can be classified: magmatic, hydrothermal, evapotranspiration, syn-sedimentary, and infiltration of meteoric water

  17. Composition change of uranium perchlorates with organic ligands upon mechanochemical activation of exchange processes

    Science.gov (United States)

    Zazhogin, A. P.; Zazhogin, A. A.; Komyak, A. I.; Umreiko, D. S.

    2008-03-01

    Results of studies on the effect of mechanochemical activation of ligand exchange processes in uranyl perchlorate-dimethylsulfoxide are presented. Spectroscopic data show that mechanical activation of the exchange process in this system results in the replacement of H2O in the first coordination sphere of uranyl UO{2/2+} by DMSO to form nanocrystals with a defined ligand sphere. Possible factors governing the noted features are considered.

  18. PURIFICATION OF URANIUM FROM URANIUM/MOLYBDENUM ALLOY

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, R; Ann Visser, A; James Laurinat, J

    2007-10-15

    The Savannah River Site will recycle a nuclear fuel comprised of 90% uranium-10% molybdenum by weight. The process flowsheet calls for dissolution of the material in nitric acid to a uranium concentration of 15-20 g/L without the formation of precipitates. The dissolution will be followed by separation of uranium from molybdenum using solvent extraction with 7.5% tributylphosphate in n-paraffin. Testing with the fuel validated dissolution and solubility data reported in the literature. Batch distribution coefficient measurements were performed for the extraction, strip and wash stages with particular focus on the distribution of molybdenum.

  19. Markov decision processes in natural resources management: observability and uncertainty

    Science.gov (United States)

    Williams, Byron K.

    2015-01-01

    The breadth and complexity of stochastic decision processes in natural resources presents a challenge to analysts who need to understand and use these approaches. The objective of this paper is to describe a class of decision processes that are germane to natural resources conservation and management, namely Markov decision processes, and to discuss applications and computing algorithms under different conditions of observability and uncertainty. A number of important similarities are developed in the framing and evaluation of different decision processes, which can be useful in their applications in natural resources management. The challenges attendant to partial observability are highlighted, and possible approaches for dealing with it are discussed.

  20. Bio-/Photo-Chemical Separation and Recovery of Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Francis,A.J.; Dodge, C.J.

    2008-03-12

    Citric acid forms bidentate, tridentate, binuclear or polynuclear species with transition metals and actinides. Biodegradation of metal citrate complexes is influenced by the type of complex formed with metal ions. While bidentate complexes are readily biodegraded, tridentate, binuclear and polynuclear species are recalcitrant. Likewise certain transition metals and actinides are photochemically active in the presence of organic acids. Although the uranyl citrate complex is not biodegraded, in the presence of visible light it undergoes photochemical oxidation/reduction reactions which result in the precipitation of uranium as UO{sub 3} {center_dot} H{sub 2}O. Consequently, we developed a process where uranium is extracted from contaminated soils and wastes by citric acid. The citric-acid extract is subjected to biodegradation to recover the toxic metals, whereas uranyl citrate which is recalcitrant remains in solution. Photochemical degradation of the uranium citrate complex resulted in the precipitation of uranium. Thus the toxic metals and uranium in mixed waste are recovered in separate fractions for recycling or for disposal. The use of naturally-occurring compounds and the combined chemical and microbiological treatment process is more efficient than present methods and should result in considerable savings in cost.

  1. Uranium industry annual 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    The Uranium Industry Annual 1996 (UIA 1996) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing. The UIA 1996 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. Data on uranium raw materials activities for 1987 through 1996 including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2006, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, uranium imports and exports, and uranium inventories are shown in Chapter 2. A feature article, The Role of Thorium in Nuclear Energy, is included. 24 figs., 56 tabs.

  2. A literature review of interaction of oxidized uranium species and uranium complexes with soluble organic matter

    Science.gov (United States)

    Jennings, Joan K.; Leventhal, J.S.

    1978-01-01

    Organic material is commonly found associated with uranium ores in sandstone-type deposits. This review of the literature summarizes the classes and separations of naturally occurring organic material but the emphasis is on soluble organic species. The main class of materials of interest is humic substances which are high-molecular-weight complex molecules that are soluble in alkaline solution. These humic substances are able to solubilize (make soluble) minerals and also to complex [by ion exchange and (or) chelation] many cations. The natural process of soil formation results in both mineral decomposition and element complexing by organic species. Uranium in solution, such as ground water, can form many species with other elements or complexes present depending on Eh and pH. In natural systems (oxidizing Eh, pH 5-9) the uranium is usually present as a complex with hydroxide or carbonate. Thermodynamic data for these species are presented. Interacting metals and organic materials have been observed in nature and studied in the laboratory by many workers in diverse scientific disciplines. The results are not easily compared. Measurements of the degree of complexation are reported as equilibrium stability constant determinations. This type of research has been done for Mn, Fe, Cu, Zn, Pb, Ni, Co, Mg, Ca, Al, and to a limited degree for U. The use of Conditional Stability Constants has given quantitative results in some cases. The methods utilized in experiments and calculations are reviewed.

  3. Natural processes as means to create local connection

    DEFF Research Database (Denmark)

    Sjøstedt, Victoria

    2010-01-01

    and practical knowledge about how to apply natural processes to planning. This paper investigates how natural process thinking caters for a connection to the local and the site-specific in a Chinese context of transformation. Natural process thinking as a site-based urban design approach is understood......Contemporary large scale residential developments in China are often built up in a tabula rasa fashion, with little consideration to natural and cultural landscapes. Site-specific readings also turn into a difficult endeavor since socio-cultural patterns in China are under rapid transformation......, a particular challenge for foreign architects as they operate in an unfamiliar context. A deep understanding of how to apply natural processes to construction and settlement patterns can be found in Chinese vernacular approaches but are rarely practiced today since architects in general lack more profound...

  4. The meaning of "natural": process more important than content.

    Science.gov (United States)

    Rozin, Paul

    2005-08-01

    The meaning of the desirable attribute "natural" was explored in two samples, American college students and adults in the Philadelphia jury pool. Participants rated the naturalness of a variety of "natural" entities, before and after they were transformed by operations such as freezing, adding or removing components, mixing with other natural or unnatural entities, domestication, and genetic engineering. Results support four hypotheses. First, the principle of contagion accounts for many aspects of the reduction of naturalness by contact with unnatural entities. Second, chemical transformations reduce naturalness much more than physical transformations do. Third, the history of an entity's processing is more important in determining its naturalness than is the nature of the entity's contents. Fourth, mixing like natural entities (e.g., water from different sources) does not markedly reduce naturalness. The insertion of a gene from another species, the process used in producing genetically modified organisms, produces the biggest drop in naturalness; domestication, a human-accomplished activity that changes genotype and phenotype in major ways, is considered much less damaging to naturalness.

  5. Equilibrium, kinetic and thermodynamic studies of uranium biosorption by calcium alginate beads.

    Science.gov (United States)

    Bai, Jing; Fan, Fangli; Wu, Xiaolei; Tian, Wei; Zhao, Liang; Yin, Xiaojie; Fan, Fuyou; Li, Zhan; Tian, Longlong; Wang, Yang; Qin, Zhi; Guo, Junsheng

    2013-12-01

    Calcium alginate beads are potential biosorbent for radionuclides removal as they contain carboxyl groups. However, until now limited information is available concerning the uptake behavior of uranium by this polymer gel, especially when sorption equilibrium, kinetics and thermodynamics are concerned. In present work, batch experiments were carried out to study the equilibrium, kinetics and thermodynamics of uranium sorption by calcium alginate beads. The effects of initial solution pH, sorbent amount, initial uranium concentration and temperature on uranium sorption were also investigated. The determined optimal conditions were: initial solution pH of 3.0, added sorbent amount of 40 mg, and uranium sorption capacity increased with increasing initial uranium concentration and temperature. Equilibrium data obtained under different temperatures were fitted better with Langmuir model than Freundlich model, uranium sorption was dominated by a monolayer way. The kinetic data can be well depicted by the pseudo-second-order kinetic model. The activation energy derived from Arrhenius equation was 30.0 kJ/mol and the sorption process had a chemical nature. Thermodynamic constants such as ΔH(0), ΔS(0) and ΔG(0) were also evaluated, results of thermodynamic study showed that the sorption process was endothermic and spontaneous.

  6. SEPARATION OF URANIUM FROM THORIUM

    Science.gov (United States)

    Hellman, N.N.

    1959-07-01

    A process is presented for separating uranium from thorium wherein the ratio of thorium to uranium is between 100 to 10,000. According to the invention the thoriumuranium mixture is dissolved in nitric acid, and the solution is prepared so as to obtain the desired concentration within a critical range of from 4 to 8 N with regard to the total nitrate due to thorium nitrate, with or without nitric acid or any nitrate salting out agent. The solution is then contacted with an ether, such as diethyl ether, whereby uranium is extracted into ihe organic phase while thorium remains in the aqueous phase.

  7. Modeling Uranium Transport in Koongarra, Australia: The Effect of a Moving Weathering Zone

    NARCIS (Netherlands)

    Leijnse, A.; Weerd, van de H.; Hassanizadeh, S.M.

    2001-01-01

    Natural analogues are an important source of long-term data and may be viewed as naturally occurring experiments that often include processes, phenomena, and scenarios that are important to nuclear waste disposal safety assessment studies. The Koongarra uranium deposit in the Alligator Rivers region

  8. Study of the oocyte degenerescence at mouse: role of the caspases and toxicity of natural uranium; Etude de la degenerescence ovocytaire chez la souris: role des caspases et toxicite de l'uranium naturel

    Energy Technology Data Exchange (ETDEWEB)

    Arnault, E

    2008-04-15

    The aim of this work is to estimate the uranium toxicity on the ovarian function and on the oocyte and more fundamentally to characterize the molecular ways regulating the oocyte degenerescence. At first, will be described the different exposure modes at uranium and the known toxic effects of this heavy metal on man and animal. The mechanisms regulating the follicle genesis and the oogenesis are then developed. At last, will be given the data available in literature and concerning the apoptosis ways intervening in the follicular atresia and in the oocyte degenerescence while referring to the known ways of the somatic cells. (O.M.)

  9. Fast Oxidation Processes in a Naturally Reduced Aquifer Zone Caused by Dissolved Oxygen

    Science.gov (United States)

    Davis, J. A.; Jemison, N. E.; Williams, K. H.; Hobson, C.; Bush, R. P.

    2014-12-01

    The occurrence of naturally reduced zones is quite common in alluvial aquifers in the western U.S.A. due to the burial of woody debris in flood plains. The naturally reduced zones are heterogeneously dispersed in such aquifers and are characterized by high concentrations of organic carbon and reduced phases, including iron sulfides and reduced forms of metals, including uranium(IV). The persistence of high concentrations of dissolved uranium(VI) at uranium-contaminated aquifers on the Colorado Plateau has been attributed to slow oxidation of insoluble uranium(IV) mineral phases that are found in association with these natural reducing zones, although there is little understanding of the relative importance of various potential oxidants. Three field experiments were conducted within an alluvial aquifer adjacent to the Colorado River near Rifle, CO wherein groundwater associated with naturally reduced zones was pumped into a gas-impermeable tank, mixed with a conservative tracer (Br-), bubbled with a gas phase composed of 97% O2 and 3% CO2, and then returned to the subsurface in the same well from which it was withdrawn. Within minutes of re-injection of the oxygenated groundwater, dissolved uranium(VI) concentrations increased from less than 1 μM to greater than 2.5 μM, demonstrating that oxygen can be an important oxidant for uranium in these field systems if supplied to the naturally reduced zones. Small concentrations of nitrate were also observed in the previously nitrate-free groundwater, and Fe(II) decreased to the detection limit. These results contrast with other laboratory and field results in which oxygen was introduced to systems containing high concentrations of mackinawite (FeS) rather than the more crystalline iron sulfides found in aged, naturally reduced zones. The flux of oxygen to the naturally reduced zones in the alluvial aquifers occurs mainly through interactions between groundwater and gas phases at the water table, and seasonal variations

  10. Uranium from seawater

    Energy Technology Data Exchange (ETDEWEB)

    Gregg, D.; Folkendt, M.

    1982-09-21

    A novel process for recovering uranium from seawater is proposed and some of the critical technical parameters are evaluated. The process, in summary, consists of two different options for contacting adsorbant pellets with seawater without pumping the seawater. It is expected that this will reduce the mass handling requirements, compared to pumped seawater systems, by a factor of approximately 10/sup 5/, which should also result in a large reduction in initial capital investment. Activated carbon, possibly in combination with a small amount of dissolved titanium hydroxide, is expected to be the preferred adsorbant material instead of the commonly assumed titanium hydroxide alone. The activated carbon, after exposure to seawater, can be stripped of uranium with an appropriate eluant (probably an acid) or can be burned for its heating value (possible in a power plant) leaving the uranium further enriched in its ash. The uranium, representing about 1% of the ash, is then a rich ore and would be recovered in a conventional manner. Experimental results have indicated that activated carbon, acting alone, is not adequately effective in adsorbing the uranium from seawater. We measured partition coefficients (concentration ratios) of approximately 10/sup 3/ in seawater instead of the reported values of 10/sup 5/. However, preliminary tests carried out in fresh water show considerable promise for an extraction system that uses a combination of dissolved titanium hydroxide (in minute amounts) which forms an insoluble compound with the uranyl ion, and the insoluble compound then being sorbed out on activated carbon. Such a system showed partition coefficients in excess of 10/sup 5/ in fresh water. However, the system was not tested in seawater.

  11. Field-scale model for the natural attenuation of uranium at the Hanford 300 area using high performance computing

    Energy Technology Data Exchange (ETDEWEB)

    Lichtner, Peter C [Los Alamos National Laboratory; Hammond, Glenn E [PNNL

    2009-01-01

    Three-dimensional reactive flow and transport simulations are carried out to better understand the persistence of uranium [U(VI)] at the Hanford 300 Area bordering the Columbia River. The massively parallel code PFLOTRAN developed under a DOE SciDAC-2 project is employed in the simulations. The calculations were carried out on 4096 processor cores on ORNL's Jaguar XT4 & 5 Cray supercomputers with run times on the order of 6 hours, equivalent to several years if performed on a single processor with sufficient memory. A new conceptual model is presented for understanding present-day and future attenuation rates of U(VI) at the 300 Area site. Unique to the conceptual model is the recognition of three distinct phases in the evolution of the site corresponding to: (I) initial emplacement of waste; (II) present-day conditions of slow leaching of U(VI) from the Hanford sediments; and (III) the complete removal of non-labile U(VI) from the source region. This work focuses on Phase II. Both labile and non-labile forms of U(VI) are included in the model as sorbed and mineralized forms of U(VI), respectively. The non-labile form plays an important role in providing a long-term source of U(VI) as it slowly leaches out of the Hanford sediment. Rapid fluctuations in the Columbia River stage on hourly, weekly and seasonal time scales are found to' playa major role in determining the migration behavior of U(VI). The calculations demonstrate that U(VI) is released into the Columbia River at a highly fluctuating rate in a ratchet-like behavior with nonzero U(VI) flux occurring only during flow from contaminated sediment into the river. The cumulative flux, however, is found to increase approximately linearly with time. The flow rate and U(VI) flux into the Columbia River predicted by the model is highly sensitive to the value used in the conductance boundary condition at the river-sediment interface. By fitting the conductance to the measured piezometric head at well 399

  12. Filiform-mode hydride corrosion of uranium surfaces

    Science.gov (United States)

    Hill, M. A.; Schulze, R. K.; Bingert, J. F.; Field, R. D.; McCabe, R. J.; Papin, P. A.

    2013-11-01

    Hydride nucleation and growth has previously been studied in uranium with an air-formed oxide. Preferred directional growth of uranium hydride has not been observed, presumably due to the constraint of the oxide layer and/or the presence of a surface layer distorted by mechanical grinding and polishing. Instead, hydrides typically first form as subsurface blisters that do not exhibit preferred growth directionality. By eliminating the strained surface layer through electropolishing, removing the natural oxide through ion sputtering, avoiding exposure of the uranium to air, and then exposing uranium to high purity hydrogen in an environmental cell, hydride growth patterns emerge that correspond to defect structures within the microstructure. These hydride growth patterns are similar to filiform corrosion, a type of corrosion that frequently forms under thin protective films. This work describes the first reported observation of filiform-like corrosion in uranium. The uranium hydride initiates at defects, but grows into filaments up to 20 μm wide, and tends to form in straight lines, largely propagating along twin boundaries. Propagation is driven by hydrogen reaction at the filament head, promoted by more efficient delivery of reactant. However, this phenomenon does not involve an electrochemical process associated with conventional filiform corrosion and is therefore described as filiform-like. Hydride growth was observed using optical microscopy for a period of nearly three years. Sample characterization included automated electron backscatter diffraction (EBSD) measurements to determine growth directions. Observation of this anomalous hydride growth provides clues as to the mechanisms operating in uranium hydriding for more conventionally prepared sample surfaces.

  13. Characterization of uranium and uranium-zirconium deposits produced in electrorefining of spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Totemeier, T.C.

    1997-09-01

    This paper describes the metallurgical characterization of deposits produced in molten salt electrorefining of uranium and uranium - 10.% zirconium alloy. The techniques of characterization are described with emphasis on considerations given to the radioactive and pyrophoric nature of the samples. The morphologies observed and their implications for deposit performance are also presented - samples from pure uranium deposits were comprised of chains of uranium crystals with a characteristic rhomboidal shape, while morphologies of samples from deposits containing zirconium showed more polycrystalline features. Zirconium was found to be present as a second, zirconium metal phase at or very near the uranium-zirconium dendrite surfaces. Higher collection efficiencies and total deposit weights were observed for the uranium-zirconium deposits; this performance increase is likely a result of better mechanical properties exhibited by the uranium-zirconium dendrite morphology. 18 refs., 10 figs., 1 tab.

  14. Natural Language Processing in Game Studies Research: An Overview

    Science.gov (United States)

    Zagal, Jose P.; Tomuro, Noriko; Shepitsen, Andriy

    2012-01-01

    Natural language processing (NLP) is a field of computer science and linguistics devoted to creating computer systems that use human (natural) language as input and/or output. The authors propose that NLP can also be used for game studies research. In this article, the authors provide an overview of NLP and describe some research possibilities…

  15. Physicochemical properties of dicesium tetravalent plutonium hexanitrate in uranium crystallization process

    Energy Technology Data Exchange (ETDEWEB)

    Nakahara, M; Koizumi, T [Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194 (Japan); Nomura, K, E-mail: nakahara.masaumi@jaea.go.jp [Advanced Nuclear System Reserch and Development Directorate, Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194 (Japan)

    2010-03-15

    Tetravalent Pu reacts with Cs ions to form the crystalline precipitate of Cs{sub 2}Pu(NO{sub 3}){sub 6}under certain chemical conditions during the U crystallization process. The Cs{sub 2}Pu(NO{sub 3}){sub 6}precipitate reduces the decontamination factor (DF) of Cs to U in the crystal after being washed. The solubility and thermal properties of Cs{sub 2}Pu(NO{sub 3}){sub 6} were studied with the aim of providing a characterization estimate. The solubility of Cs{sub 2}Pu(NO{sub 3}){sub 6} increased with decreases in HNO{sub 3} concentration. Loss in weight of the compound caused by thermal degradation of Cs{sub 2}Pu(NO{sub 3}){sub 6} to Cs{sub 2}PuO{sub 2}(NO{sub 3}){sub 4} was observed at 245 deg. C in thermal analysis. A uranyl nitrate hexahydrate (UNH) crystal was obtained by cooling irradiated fast reactor core fuel dissolver solution. The DF of Cs decreased with increasing the HNO{sub 3} concentration of the mother liquor because more Cs{sub 2}Pu(NO{sub 3}){sub 6} precipitates with high concentration of HNO{sub 3}.

  16. Social learning Processes and Nature-Culture relations of ...

    African Journals Online (AJOL)

    This paper explores social learning processes and nature-culture relations in a context of ..... Extract 14: In this area, it has a lot of impact because you will be politically labelled. ..... Zimbabwe Ministry of Environment and Tourism (2002).

  17. Natural Selection Is a Sorting Process: What Does that Mean?

    Science.gov (United States)

    Price, Rebecca M.

    2013-01-01

    To learn why natural selection acts only on existing variation, students categorize processes as either creative or sorting. This activity helps students confront the misconception that adaptations evolve because species need them.

  18. Natural processes as means to create local connection

    DEFF Research Database (Denmark)

    Sjøstedt, Victoria

    2010-01-01

    as a sensitive reading and response to a site’s topography, hydrology, climate and ecology. The paper is based on a study of Chinese vernacular settlements and a series of explorative drawing proposals for a new residential neighbourhood in the outskirts of the Chinese city Wuhan. Natural processes are revealed...... and utilized conceptually within the Wuhan project by mapping-techniques and environmental simulation software. The result gives implications concerning method development for architects as how to develop design concepts based on natural process thinking. Furthermore, the result shows that natural processes...... act as a viable strategy to identify and develop inherent qualities of an existing site. Natural processes, neighbourhood planning, vernacular landscapes, environmental practice, urban strategy...

  19. Maximum permissible concentrations of uranium in air

    CERN Document Server

    Adams, N

    1973-01-01

    The retention of uranium by bone and kidney has been re-evaluated taking account of recently published data for a man who had been occupationally exposed to natural uranium aerosols and for adults who had ingested uranium at the normal dietary levels. For life-time occupational exposure to uranium aerosols the new retention functions yield a greater retention in bone and a smaller retention in kidney than the earlier ones, which were based on acute intakes of uranium by terminal patients. Hence bone replaces kidney as the critical organ. The (MPC) sub a for uranium 238 on radiological considerations using the current (1959) ICRP lung model for the new retention functions is slightly smaller than for earlier functions but the (MPC) sub a determined by chemical toxicity remains the most restrictive.

  20. Airborne Plutonium and non-natural Uranium from the Fukushima DNPP found at 120 km distance a few days after reactor hydrogen explosions.

    Science.gov (United States)

    Shinonaga, Taeko; Steier, Peter; Lagos, Markus; Ohkura, Takehisa

    2014-04-01

    Plutonium (Pu) and non-natural uranium (U) originating from the Fukushima Daiichi Nuclear Power Plant (FDNPP) were identified in the atmosphere at 120 km distance from the FDNPP analyzing the ratio of number of atoms, following written as n(isotope)/n(isotope), of Pu and U. The n((240)Pu)/n((239)Pu), n((241)Pu)/n((239)Pu), n((234)U)/n((238)U), n((235)U)/n((238)U) and n((236)U)/n((238)U) in aerosol samples collected before and after the FDNPP incident were analyzed by accelerator mass spectrometry (AMS) and inductively coupled plasma mass spectrometry (ICPMS). The activity concentrations of (137)Cs and (134)Cs in the same samples were also analyzed by gamma spectrometry before the destructive analysis. Comparing the time series of analytical data on Pu and U obtained in this study with previously reported data on Pu, U, and radioactive Cs, we concluded that Pu and non-natural U from the FDNPP were transported in the atmosphere directly over a 120 km distance by aerosol and wind within a few days after the reactor hydrogen explosions. Effective dose of Pu were calculated using the data of Pu: (130 ± 21) nBq/m(3), obtained in this study. We found that the airborne Pu contributes only negligibly to the total dose at the time of the incident. However the analytical results show that the amount of Pu and non-natural U certainly increased in the environment after the incident.

  1. Applications of Weighted Automata in Natural Language Processing

    Science.gov (United States)

    Knight, Kevin; May, Jonathan

    We explain why weighted automata are an attractive knowledge representation for natural language problems. We first trace the close historical ties between the two fields, then present two complex real-world problems, transliteration and translation. These problems are usefully decomposed into a pipeline of weighted transducers, and weights can be set to maximize the likelihood of a training corpus using standard algorithms. We additionally describe the representation of language models, critical data sources in natural language processing, as weighted automata. We outline the wide range of work in natural language processing that makes use of weighted string and tree automata and describe current work and challenges.

  2. Measurement of the High Energy Neutron Flux on the Surface of the Natural Uranium Target Assembly QUINTA Irradiated by Deuterons of 4 and 8 GeV Energy

    Science.gov (United States)

    Adam, J.; Baldin, A. A.; Chilap, V.; Furman, W.; Katovsky, K.; Khushvaktov, J.; Kumar, V.; Pronskikh, V.; Mar'in, I.; Solnyshkin, A.; Suchopar, M.; Tsupko-Sitnikov, V.; Tyutyunnikov, S.; Vrzalova, J.; Wagner, V.; Zavorka, L.

    Experiments with the natural uranium target assembly "QUINTA" exposed to 4 and 8 GeV deuteron beams of the Nuclotron accelerator at the Joint Institute for Nuclear Research (Dubna) are analyzed. The reaction rates of 27Al(n,y1)24Na, 27Al(n,y2)22Na and 27Al(n,y3)7Be reactions with effective threshold energies of 5, 27, and 119 MeV were measured at both 4 GeV and 8 GeV deuteron beam energies. The average neutron fluxes between the effective threshold energies and the effective ends of the neutron spectra (which are 800 or 1000 MeV for 4 or 8 GeV deuterons) were determined. The evidence for the intensity shift of the neutron spectra to higher neutron energies with the increase of the deuteron energy from 4 GeV to 8 GeV was found from the ratios of the average neutron fluxes. The reaction rates and the average neutron fluxes were calculated with the MCNPX 2.7 code.

  3. Experiences from the Swedish programme - heavy water and natural uranium in the Aagesta cogeneration plant; Erfarenheter av den svenska linjen tungt vatten och naturligt uran i Aagesta kraftvaermeverk

    Energy Technology Data Exchange (ETDEWEB)

    Oestman, Alvar

    2002-11-01

    A short review of the Swedish programme for nuclear power in the 50's and the 60's is given, and in particular a description of the operating experiences of the Aagesta nuclear cogeneration plant, producing district heating for the south Stockholm area (12 MW{sub el} and 68 MW{sub heat}). The original Swedish nuclear programme was built on heavy water and natural uranium and had the objective to construct small nuclear plants in the vicinity of some 10 large cities in south and middle Sweden. Aagesta was the only full-scale plant to be built according to this programme, as Sweden adopted the light-water reactor policy and eventually constructed 12 large reactors at four sites. The report is based on the experiences of the author from his work at the Aagesta plant in the sixties. In an appendix, the experiences from Vattenfall (the Swedish electric utility which took over the operating responsibility for the Aagesta plant), of the plant operation is reviewed.

  4. Analytical control of reducing agents on uranium/plutonium partitioning at purex process; Controle analitico dos agentes redutores na particao uranio/plutonio no processo purex

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Izilda da Cruz de

    1995-07-01

    Spectrophotometric methods for uranium (IV), hydrazine (N{sub 2}H{sub 4}) and its decomposition product hydrazoic acid(HN{sub 3}), and hydroxylamine (NH{sub 2} OH) determinations were developed aiming their applications for the process control of CELESTE I installation at IPEN/CNEN-SP. These compounds are normally present in the U/Pu partitioning phase of the spent nuclear treatment via PUREX process. The direct spectrophotometry was used for uranium (IV) analysis in nitric acid-hydrazine solutions based on the absorption measurement at 648 nm. The azomethine compound formed by reaction of hydrazine and p-dimethylamine benzaldehyde with maximum absorption at 457 nm was the basis for the specific analytical method for hydrazine determination. The hydrazoic acid analysis was performed indirectly by its conversion into ferric azide complex with maximum absorption at 465 nm. The hydroxylamine detection was accomplished based on its selective oxidation to nitrous acid which is easily analyzed by the reaction with Griess reagent. The resulted azocompound gas a maximum absorption at 520 nm. The sensibility of 1,4x10{sup -6}M for U(IV) with 0,8% of precision, 1,6x10{sup -6}M for hydrazine with 0,8% of precision, 2,3x10{sup -6}M hydrazoic acid with 0,9% of precision and 2,5x10{sup -6}M for hydroxylamine with 0,8% of precision were achieved. The interference studies have shown that each reducing agent can be determined in the presence of each other without any interference. Uranium(VI) and plutonium have also shown no interference in these analysis. The established methods were adapted to run inside glove-boxes by using an optical fiber colorimetry and applied to process control of the CELESTE I installation. The results pointed out that the methods are reliable and safety in order to provide just-in-time information about process conditions. (author)

  5. Uranium Metal Analysis via Selective Dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, Calvin H.; Sinkov, Sergey I.; Schmidt, Andrew J.; Chenault, Jeffrey W.

    2008-09-10

    Uranium metal, which is present in sludge held in the Hanford Site K West Basin, can create hazardous hydrogen atmospheres during sludge handling, immobilization, or subsequent transport and storage operations by its oxidation/corrosion in water. A thorough knowledge of the uranium metal concentration in sludge therefore is essential to successful sludge management and waste process design. The goal of this work was to establish a rapid routine analytical method to determine uranium metal concentrations as low as 0.03 wt% in sludge even in the presence of up to 1000-fold higher total uranium concentrations (i.e., up to 30 wt% and more uranium) for samples to be taken during the upcoming sludge characterization campaign and in future analyses for sludge handling and processing. This report describes the experiments and results obtained in developing the selective dissolution technique to determine uranium metal concentration in K Basin sludge.

  6. Uranium Industry Annual, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-28

    The Uranium Industry Annual provides current statistical data on the US uranium industry for the Congress, Federal and State agencies, the uranium and electric utility industries, and the public. The feature article, ``Decommissioning of US Conventional Uranium Production Centers,`` is included. Data on uranium raw materials activities including exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities including domestic uranium purchases, commitments by utilities, procurement arrangements, uranium imports under purchase contracts and exports, deliveries to enrichment suppliers, inventories, secondary market activities, utility market requirements, and uranium for sale by domestic suppliers are presented in Chapter 2.

  7. Rate phenomena in uranium extraction by amines

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, C. F.; McDowell, W. J.

    1979-01-01

    Kinetics studies and other rate measurements are reviewed in the amine extraction of uranium and of some other related and associated metal ions. Equilibration is relatively fast in the uranium sulfate systems most important to uranium hydrometallurgy. Significantly slow equilibration has been encountered in some other systems. Most of the recorded rate information, both qualitative and quantitative, has come from exploratory and process-development work, while some kinetics studies have been directed specifically toward elucidation of extraction mechanisms. 71 references.

  8. METHOD OF PRODUCING URANIUM METAL BY ELECTROLYSIS

    Science.gov (United States)

    Piper, R.D.

    1962-09-01

    A process is given for making uranium metal from oxidic material by electrolytic deposition on the cathode. The oxidic material admixed with two moles of carbon per one mole of uranium dioxide forms the anode, and the electrolyte is a mixture of from 40 to 75% of calcium fluoride or barium fluoride, 15 to 45% of uranium tetrafluoride, and from 10 to 20% of lithium fluoride or magnesium fluoride; the temperature of the electrolyte is between 1150 and 1175 deg C. (AEC)

  9. NLP Meets the Jabberwocky: Natural Language Processing in Information Retrieval.

    Science.gov (United States)

    Feldman, Susan

    1999-01-01

    Focuses on natural language processing (NLP) in information retrieval. Defines the seven levels at which people extract meaning from text/spoken language. Discusses the stages of information processing; how an information retrieval system works; advantages to adding full NLP to information retrieval systems; and common problems with information…

  10. Nature's process for nitrogen fixation caught in action

    OpenAIRE

    Trulove, Susan

    2006-01-01

    Nitrogen gas is converted to ammonia fertilizer by a chemical process that involves high temperature and high pressure. Nature does the same thing at ambient temperature and pressure. The process, called nitrogen fixation, is essential to life as it provides nutrients to plant life.

  11. Natural Language Processing and its Use in Education

    Directory of Open Access Journals (Sweden)

    Dr. Khaled M. Alhawiti

    2014-12-01

    Full Text Available Natural Language Processing (NLP is an effective approach for bringing improvement in educational setting. Implementing NLP involves initiating the process of learning through the natural acquisition in the educational systems. It is based on effective approaches for providing a solution for various problems and issues in education. Natural Language Processing provides solution in a variety of different fields associated with the social and cultural context of language learning. It is an effective approach for teachers, students, authors and educators for providing assistance for writing, analysis, and assessment procedures. Natural Language Processing is widely integrated with the large number of educational contexts such as research, science, linguistics, e-learning, evaluations system, and contributes resulting positive outcomes in other educational settings such as schools, higher education system, and universities. The paper aims to address the process of natural language learning and its implication in the educational settings. The study also highlights how NLP can be utilized with scientific computer programs to enhance the process of education. The study follows qualitative approach. Data is collected from the secondary resources in order to identify problems faced by the teachers and students for understanding the context due to obstacles of language. Results provide effectiveness of linguistic tools such as grammar, syntax, and textual patterns that are fairly productive in educational context for learning and assessment.

  12. Uranium mining operations in Spain

    Energy Technology Data Exchange (ETDEWEB)

    Rios, J.-M.; Arnaiz, J.; Criado, M.; Lopez, A.

    1995-12-31

    The Empresa Nacional del Uranio, SA (ENUSA) was founded in 1972 to undertake and develop the industrial and procurement activities of the nuclear fuel cycle in Spain. Within the organisation of ENUSA, the Uranium Division is directly responsible for the uranium mining and production operations that have been carried out since 1973 in the area of Ciudad Rodrigo in the province of Salamanca. These activities are based on open pit mining, heap leaching and a hydrometallurgical plant (Elefante) for extracting uranium concentrates from the ore. This plant was shut down in 1993 and a new plant was started up on the same site (Quercus) with a dynamic leaching process. The nominal capacity of the new plant is 950 t U{sub 3}O{sub 8} per year. Because of the historically low uranium prices which have recently prevailed, the plant is currently running at a strategic production rate of 300 t U{sub 3}O{sub 8} per year. From 1981 to 1990, in the area of La Haba (Badajoz province), ENUSA also operated a uranium production site, based on open pit mining, and an experimental extraction plant (Lobo-G). ENUSA is currently decommissioning these installations. This paper describes innovations and improvements that ENUSA has recently introduced in the field of uranium concentrates production with a view to cutting production costs, and to improving the decommissioning and site restoration processes in those sites where production is being shut down or resources have been worked out. (author).

  13. Inherently safe in situ uranium recovery.

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-05-01

    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.

  14. Gamma-ray characterization of uranium-series nuclides and its application to the study of the Pena Blanca natural analogue site, Chihuahua, Mexico

    Science.gov (United States)

    Wong, Virgina

    Two natural analogue sites located in the Pena Blanca Uranium District, Chihuahua, Mexico were characterized for radionuclide mobility. Analogue I is used to assess the long-term behavior of uranium-series nuclides in a host rock and geochemical environment that is similar to the proposed high-level waste repository at Yucca Mountain, Nevada. Analogue II represents a former dump site to assess short-term radionuclide mobility. Gamma-ray spectroscopy analysis was used to measure radioactivity of the U-series nuclides. Samples analyzed from Analogue I consist of: (1) fracture-infillings associated with different alteration assemblages collected within and outside the breccia pipe from various levels of the deposit and (2) fracture-infillings collected along an east-west trending fracture which intersects the breccia pipe and extends into the host rock. Alteration mineralogy, established via X-ray diffraction analysis, consists of pure kaolinite, a mixture of Fe-oxyhydroxide (goethite, hematite) With inclusions of jarosite and alunite, and carbonates. Results from activity ratios of 230Th/238U versus 226Ra/230Th indicate that majority of the Fe-oxyhydroxides from the breccia zone show a slight disequilibrium with respect to Ra enrichment and U depletion. This observation is modeled as requiring a multiple-event history of U mobility. An amorphous Fe sample distal to the breccia zone shows similar behavior but to a greater extent. This extreme behavior is ascribed to initially low U content and greater late-stage U removal. Two Fe-oxyhydroxide samples from Within the breccia pipe also display multiple-event stages but exhibit both Ra and U leaching. This behavior is shared by Fe-oxyhydroxide samples collected inside and peripheral to the breccia zone from the east-west trending fracture. Finally, three samples, two Fe phase samples outside the breccia zone and a kaolinite inside the breccia zone, show Ra and U enrichment. Also, a distal Fe-oxyhydroxide sample from the

  15. Conceptual process synthesis for recovery of natural products from plants

    DEFF Research Database (Denmark)

    Malwade, Chandrakant R.; Qu, Haiyan; Rong, Ben-Guang;

    2013-01-01

    A systematic method of conceptual process synthesis for recovery of natural products from their biological sources is presented. This methodology divides the task into two major subtasks namely, isolation of target compound from a chemically complex solid matrix of biological source (crude extract......) and purification of target compound(s) from the crude extract. Process analytical technology (PAT) is used in each step to understand the nature of material systems and separation characteristics of each separation method. In the present work, this methodology is applied to generate process flow sheet for recovery...

  16. Contribution of Uranium-Bearing Evaporites to Plume Persistence Issues at a Former Uranium Mill Site Riverton, Wyoming, USA

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Raymond [Navarro Research and Engineering; Dam, William [U.S. Department of Energy, Legacy Management; Campbell, Sam [Navarro Research and Engineering; Campbell, James [U.S. Geological Survey; Morris, Sarah [Navarro Research and Engineering; Tigar, Aaron [Navarrao Research and Engineering

    2016-08-01

    • Evaporites occur in an unsaturated silt layer, which is underlain by a sand and gravel aquifer. • These evaporites are rich in chloride across the site. • Uranium concentrations are higher in the evaporites that overlie the uranium contaminant plume. • Flooding can solubilize the evaporites in the silt layer and release chloride, sulfate (not shown), and uranium into the underlyingsand and gravel aquifer. • The uranium-rich evaporites can delay natural flushing, creating plume persistence near the Little Wind River.

  17. On the chemical identification and visualization of uranium species in biofilms and Euglena mutabilis cells; Zur chemischen Identifizierung und Visualisierung von Uran-Spezies in Biofilmen und Euglena mutabilis Zellen

    Energy Technology Data Exchange (ETDEWEB)

    Brockmann, Sina

    2013-11-14

    For risk assessment of anthropogenic uranium contaminations in the environment a detailed knowledge of the migration and immobilization behavior is required to prevent health hazards for humans and animals caused by an uncontrolled discharge of uranium. Hence, comprehensive studies on the interactions of uranium with the environment are required. Besides the influences of the geological materials, there is a huge effect of the biosphere, especially the interactions with microorganisms and biofilms, on the properties of uranium in the environment. The aim of this study was to investigate and to describe naturally occurring biofilms from real uranium contaminated areas and their influence on the uranium migration. The investigations in this study on the localization and the speciation of the uranium in the biosystems were primarily done with a coupled system of laser scanning microscopy (CLSM) and laser induced fluorescence spectroscopy (LIFS). Natural biofilms collected from two uranium contaminated acid mine drainage (AMD) environments, the former uranium mine in Koenigstein (Saxony, Germany) and the former Gessenheap near Ronneburg (Thuringia,Germany), were investigated in this study. The chosen samples represent typical biofilm communities living in AMD water and are exemplary for potentially occurring scenarios of contaminated mining water both in the underground and on the surface. The investigation on the interactions between uranium and Euglena mutabilis, which is a typical unicellular microorganism that can be found in acidic, uranium and other heavy metal containing waters, was another important part of this study. Bioaccumulation experiments of uranium on living Euglena mutabilis cells depending on the pH (pH 3 - 6) and on the background media in sodium perchlorate (9 g/l) or sodium sulfate (3.48 g/l) solution containing 0.01 mM uranium show an effective immobilization of uranium. At the acidic pH-values (pH 3 - 4) over 90 % of the added uranium was

  18. Rare earth elements (REE) as natural and applied tracers in the catchment area of Gessental valley, former uranium mining area of Eastern Thuringia, Germany

    Science.gov (United States)

    Buechel, G.; Merten, D.; Geletneky, J. W.; Kothe, E.

    2003-04-01

    Between 1947 and 1990 about 113.000 t of uranium were excavated at the former uranium mining site of Ronneburg (Eastern Thuringia, Germany). The legacy consists of more than 200 million m^3 of metasedimentary rocks rich in organic matter, sulfides and heavy metals originally deposited in mining heaps at the surface. The metasedimentary rocks formed under anoxic conditions about a 400 Mio. years ago are now exposed to oxic conditions. The oxidation of markasite and pyrite results in the formation of H_2SO_4. The formation of acid mine drainage (AMD) leads to high concentrations of uranium, rare earth elements (REE) and other heavy metals in surface water, seepage water and groundwater. This mobilization is due to alteration enhanced by high microbial activity and low pH. The tolerance mechanisms towards heavy metal pollution of soil substrate and surface/groundwater has allowed the selection of microbes which have, e.g. specific transporter genes and which are associated to plants in symbiotic interactions like mycorrhiza. In order to follow the processes linking alteration of metasedimentary rocks to biological systems the use of tracers is needed. One group of such tracers occuring in high concentrations in the water phase at the Ronneburg mining site are the REE (La-Lu) which are featured by very similar chemical behaviour. They show smooth but continuous variations of their chemical behaviour as a function of atomic number. For seepage water of the waste rock dump Nordhalde - sampled over a period of two years - the shale normalized REE patterns show enrichment of heavy REE and only minor variations, although the concentration differs. At sampling points in the surface water and in groundwater rather similar REE patterns were observed. Thus, REE can be used as tracers to identify diffuse inflow of REE-rich acid mine drainage of the dumps into the creek and the sediments. The absolute concentrations of REE in the creek and in ground water are up to 1000 times

  19. Use of Natural Zeolite to Upgrade Activated Sludge Process

    Directory of Open Access Journals (Sweden)

    Hanife Büyükgüngör

    2003-01-01

    Full Text Available The objective of this study was to achieve better efficiency of phosphorus removal in an enhanced biological phosphorus removal process by upgrading the system with different amounts of natural zeolite addition. The system performance for synthetic wastewater containing different carbon sources applied at different initial concentrations of phosphorus, as well as for municipal wastewater, was investigated. Natural zeolite addition in the aerobic phase of the anaerobic/aerobic bioaugmented activated sludge system contributed to a significant improvement of phosphorus removal in systems with synthetic wastewater and fresh municipal wastewater. Improvement of phosphorus removal with regard to the control reactors was higher with the addition of 15 than with 5 g/L of natural zeolite. In reactors with natural zeolite addition with regard to the control reactors significantly decreased chemical oxygen demand, ammonium and nitrate, while higher increment and better-activated sludge settling were achieved, without changes in the pH-values of the medium. It was shown that the natural zeolite particles are suitable support material for the phosphate-accumulating bacteria Acinetobacter calcoaceticus (DSM 1532, which were adsorbed on the particle surface, resulting in increased biological activity of the system. The process of phosphorus removal in a system with bioaugmented activated sludge and natural zeolite addition consisted of: metabolic activity of activated sludge, phosphorus uptake by phosphate-accumulating bacteria adsorbed on the natural zeolite particles and suspended in solution, and phosphorus adsorption on the natural zeolite particles.

  20. Separation process design for isolation and purification of natural products

    DEFF Research Database (Denmark)

    Malwade, Chandrakant R.

    Natural products are defined as secondary metabolites produced by plants and form a vast pool of compounds with unlimited chemical and functional diversity. Many of these secondary metabolites are high value added chemicals that are frequently used as ingredients in food, cosmetics, pharmaceutica...... information is used to further optimize the process flow sheet. Chemometric methods have been used to extract molecular level information for understanding the process streams in relation to their separation operations....... and other consumer products. Therefore, process technology towards industrial scale production of such high value chemicals from plants has significant value. Natural products can be obtained in pure form via synthetic or semi-synthetic route, but due to their complicated nature these methods have not been...... developed to the extent of industrial production for majority of natural products. Thus, isolation and purification of such natural products from plants is the most viable way to obtain natural products in pure form. This PhD project is mainly concerned with the design of separation process to isolate...

  1. Technical Report on the Behavior of Trace Elements, Stable Isotopes, and Radiogenic Isotopes During the Processing of Uranium Ore to Uranium Ore Concentrate

    Energy Technology Data Exchange (ETDEWEB)

    Marks, N. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Borg, L. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Eppich, G. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gaffney, A. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Genneti, V. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hutcheon, I. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kristo, M. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lindvall, R. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ramon, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Robel, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Roberts, S. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schorzman, K. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sharp, M. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Singleton, M. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Williams, R. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-09

    The goals of this SP-1 effort were to understand how isotopic and elemental signatures behave during mining, milling, and concentration and to identify analytes that might preserve geologic signatures of the protolith ores. The impurities that are preserved through the concentration process could provide useful forensic signatures and perhaps prove diagnostic of sample origin.

  2. High surface-area amidoxime-based polymer fibers co-grafted with various acid monomers yielding increased adsorption capacity for the extraction of uranium from seawater.

    Science.gov (United States)

    Oyola, Yatsandra; Dai, Sheng

    2016-06-07

    Uranium is dissolved in the ocean at a uniform concentration of 3.34 ppb, which translates to approximately 4-5 billion tons of uranium. The development of adsorbents that can extract uranium from seawater has been a long term goal, but the extremely dilute uranium concentration along with the competition of other metal salts (which are at higher concentrations) has hindered the development of an economical adsorption process. Several acid monomers were co-grafted with acrylonitrile (AN) to help increase the hydrophilicity of the adsorbent to improve access to the metal adsorption sites. Grafting various acid monomers on PE fibers was found to significantly affect the uranium adsorption in simulated seawater in the following order: acrylic acid (AA) uranium adsorption capacity significantly increased when Mohr's salt was added with acrylic acid, most likely due to the reduction of co-polymerization of the monomers. When testing under more realistic conditions, the acid-grafted PE fiber adsorbents were exposed to natural seawater (more dilute uranium), the uranium adsorption capacity increased in the following order: MAA uranium adsorption capacity with each acid monomer was related to higher grafting of AN and therefore a higher conversion to amidoxime (AO).

  3. Investigations on uranium sorption on bentonite and montmorillonite, respectively, and uranium in environmental samples; Untersuchungen zur Uransorption an Bentonit bzw. Montmorillonit sowie von Uran in Umweltproben

    Energy Technology Data Exchange (ETDEWEB)

    Azeroual, Mohamed

    2010-09-22

    The geotechnical barrier is an important component of a geological repository and consists of compacted bentonite surrounding radioactive waste containers. Its most important functions are, to retard the radionuclide migration into the biosphere and to prevent groundwater contact with containers. lt is therefore of central importance to investigate the bentonite material on its capacity to sorb radionuclides under near-natural chemical and physical conditions. The purpose of this work was to study the adsorption of uranium(VI) on bentonit and on montmorillonite-standards at high uranium concentrations. Thereby, a special account was given to the calcium-uranyl-carbonate complexation, which leads to the formation of very stable and mobile uncharged Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} complex. Results of batch experiments showed that the dicalcium-uranyl-tricarbonate complexation lowers the uranium(VI) sorption on natural clay (bentonite) by a factor of up to 3. After 21 days of contact time, about 40 % and 20 % of the initial uranium(VI)concentration were sorbed on Na-bentonite and ea-bentonite, respectively, from a solution with Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} dominating the uranium(VI) speciation. On the contrary, about 55 % of the initial uranium(VI)-concentration were sorbed on thes clays from the solution, in which (UO{sub 2}){sub 2}CO{sub 3}(OH){sub 3}{sup -} complex dominated the uranium(VI) speciation. Thus uranium(VI) sorption is more strongly influenced by the solution composition than by bentonite type. Na-bentonite should be used instead of ea-bentonite as a geotechnical barrier, since calcium-uranyl-carbonate complexation may be a realistic scenario. Further SEM-EDX and HREM-EDX studies showed that uranium(VI) sorption occurred predominantly on montmorillonite, which is the main component of bentonite. Uranium(VI) sorption on bentonite's accessory Minerals (pyrite, calcite, mica, and feldspar) was not observed. Investigation of uranium

  4. Visual Execution and Data Visualisation in Natural Language Processing

    OpenAIRE

    Rodgers, Peter; Gaizauskas, Robert; Humphreys, Kevin; Cunningham, Hamish

    1997-01-01

    We describe GGI, a visual system that allows the user to execute an automatically generated data flow graph containing code modules that perform natural language processing tasks. These code modules operate on text documents. GGI has a suite of text visualisation tools that allows the user useful views of the annotation data that is produced by the modules in the executable graph. GGI forms part of the GATE natural language engineering system.

  5. Finite-State Methodology in Natural Language Processing

    Directory of Open Access Journals (Sweden)

    Michal Korzycki

    2001-01-01

    Full Text Available Recent mathematical and algorithmic results in the field of finite-state technology, as well the increase in computing power, have constructed the base for a new approach in natural language processing. However the task of creating an appropriate model that would describe the phenomena of the natural language is still to be achieved. ln this paper I'm presenting some notions related to the finite-state modelling of syntax and morphology.

  6. Uranium Pyrophoricity Phenomena and Prediction (FAI/00-39)

    Energy Technology Data Exchange (ETDEWEB)

    PLYS, M.G.

    2000-10-10

    The purpose of this report is to provide a topical reference on the phenomena and prediction of uranium pyrophoricity for the Hanford Spent Nuclear Fuel (SNF) Project with specific applications to SNF Project processes and situations. Spent metallic uranium nuclear fuel is currently stored underwater at the K basins in the Hanford 100 area, and planned processing steps include: (1) At the basins, cleaning and placing fuel elements and scrap into stainless steel multi-canister overpacks (MCOs) holding about 6 MT of fuel apiece; (2) At nearby cold vacuum drying (CVD) stations, draining, vacuum drying, and mechanically sealing the MCOs; (3) Shipping the MCOs to the Canister Storage Building (CSB) on the 200 Area plateau; and (4) Welding shut and placing the MCOs for interim (40 year) dry storage in closed CSB storage tubes cooled by natural air circulation through the surrounding vault. Damaged fuel elements have exposed and corroded fuel surfaces, which can exothermically react with water vapor and oxygen during normal process steps and in off-normal situations, A key process safety concern is the rate of reaction of damaged fuel and the potential for self-sustaining or runaway reactions, also known as uranium fires or fuel ignition. Uranium metal and one of its corrosion products, uranium hydride, are potentially pyrophoric materials. Dangers of pyrophoricity of uranium and its hydride have long been known in the U.S. Department of Energy (Atomic Energy Commission/DOE) complex and will be discussed more below; it is sufficient here to note that there are numerous documented instances of uranium fires during normal operations. The motivation for this work is to place the safety of the present process in proper perspective given past operational experience. Steps in development of such a perspective are: (1) Description of underlying physical causes for runaway reactions, (2) Modeling physical processes to explain runaway reactions, (3) Validation of the method

  7. The mechanism of uranium transformation from U(VI) into nano-uramphite by two indigenous Bacillus thuringiensis strains

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Xiaohong; Chen, Zhi [Key Lab of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University, Ministry of Education & Fujian–Taiwan Joint Center for Ecological Control of Crop Pests, Fuzhou, Fujian 350002 (China); Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Chen, Fanbing [Key Lab of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University, Ministry of Education & Fujian–Taiwan Joint Center for Ecological Control of Crop Pests, Fuzhou, Fujian 350002 (China); Cheng, Yangjian [Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Lin, Zhang, E-mail: zlin@fjirsm.ac.cn [Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); School of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); Guan, Xiong, E-mail: guanxfafu@126.com [Key Lab of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University, Ministry of Education & Fujian–Taiwan Joint Center for Ecological Control of Crop Pests, Fuzhou, Fujian 350002 (China)

    2015-10-30

    Highlights: • Indigenous B. thuringiensis exhibited highly accumulation ability to U(VI) in the absence of additional nutrients. • The amorphous uranium compound would transformed into crystalline nano-uramphite by B. thuringiensis. • The chemical nature of formed U-species were monitored. • The cell-free extracts of B. thuringiensis had better uranium-immobilization ability than its cell debris. • Provided the understanding of the uranium transformation mechanism. - Abstract: The mechanism of uranium transformation from U(VI) into nano-uramphite by two indigenous Bacillus thuringiensis strains was investigated in the present work. Our data showed that the bacteria isolated from uranium mine possessed highly accumulation ability to U(VI), and the maximum accumulation capacity was around 400 mg U/g biomass (dry weight). X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR) analyzes indicated that the U(VI) was adsorbed on the bacterial surface firstly through coordinating with phosphate, −CH{sub 2} and amide groups, and then needle-like amorphous uranium compounds were formed. With the extension of time, the extracellular crystalline substances were disappeared, but some particles were appeared in the intracellular region, and these particles were characterized as tetragonal-uramphite. Moreover, the disrupted experiment indicated that the cell-free extracts had better uranium-immobilization ability than cell debris. Our findings provided the understanding of the uranium transformation process from amorphous uranium to crystalline uramphite, which would be useful in the regulation of uranium immobilization process.

  8. Mitigating uranium in groundwater: prospects and limitations.

    Science.gov (United States)

    Noubactep, C; Meinrath, G; Dietrich, P; Merkel, B

    2003-09-15

    Removal of uranium(VI) by zerovalent iron has been suggested as a feasible pathway to control uranium contaminations in seepage waters. Available information in the literature however presents discrepant evidence on the process responsible for the mitigation effect. On basis of an EH-pH diagram of uranium and iron, it is outlined that these discrepancies may be explained by the aqueous chemistry of uranium and iron. Additional effects contributing to the complexity of the system are given. Solubilization experiments using scrap iron together with water works sludge, MnO2, and pyrite indicate that U(VI) is immobilized by iron corrosion products after about 50 days.

  9. Colorimetric detection of uranium in water

    Science.gov (United States)

    DeVol, Timothy A [Clemson, SC; Hixon, Amy E [Piedmont, SC; DiPrete, David P [Evans, GA

    2012-03-13

    Disclosed are methods, materials and systems that can be used to determine qualitatively or quantitatively the level of uranium contamination in water samples. Beneficially, disclosed systems are relatively simple and cost-effective. For example, disclosed systems can be utilized by consumers having little or no training in chemical analysis techniques. Methods generally include a concentration step and a complexation step. Uranium concentration can be carried out according to an extraction chromatographic process and complexation can chemically bind uranium with a detectable substance such that the formed substance is visually detectable. Methods can detect uranium contamination down to levels even below the MCL as established by the EPA.

  10. Learning to rank for information retrieval and natural language processing

    CERN Document Server

    Li, Hang

    2014-01-01

    Learning to rank refers to machine learning techniques for training a model in a ranking task. Learning to rank is useful for many applications in information retrieval, natural language processing, and data mining. Intensive studies have been conducted on its problems recently, and significant progress has been made. This lecture gives an introduction to the area including the fundamental problems, major approaches, theories, applications, and future work.The author begins by showing that various ranking problems in information retrieval and natural language processing can be formalized as tw

  11. 离子交换纤维处理含铀矿井水%Processing of uranium-bearing pit water by ion exchange fibre

    Institute of Scientific and Technical Information of China (English)

    李建华; 王红英; 程威; 邓锦勋; 李红

    2012-01-01

    采用静态吸附法和动态吸附法研究了强碱性阴离子交换纤维(简称纤-Ⅱ)对含铀矿井水的吸附行为,测定了接触时间、床层高度对吸附和淋洗的影响,以及铀在溶液和离子交换纤维中的平衡浓度.试验结果表明,纤-Ⅱ比201×7阴离子交换树脂吸附速度和淋洗速度快,吸附容量与201×7树脂相当;Na2CO3+NaHCO3作为淋洗剂淋洗效果好.纤Ⅱ可以从含铀矿井水中回收铀,并使处理后的矿井水达标排放.%Methods of static adsorption and dynamic adsorption are used to study the adsorption of uranium-bearing pit water on ion exchange fibre. The effects of contact time, height of ion exchange fibre column, and balance of uranium between aqueous phase and fibre phase are investigated. It is indicated that ion exchange fibre presents advantages such as fast adsorption, fast elution, same capacity compared with ion exchange resin. 106 g/L Na2CO3 +5 g/L NaHCO3 is a suitable eluant for ion exchange fibre. Therefore ion exchange fibre can be selected to process uranium-bearing pit water.

  12. Nondestructive analysis of the natural uranium mass through the measurement of delayed neutrons using the technique of pulsed neutron source; Analise nao destrutiva da massa de uranio natural atraves da medida de neutrons atrasados com o uso da tecnica de fonte pulsada de neutrons rapidos

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Paulo Rogerio Pinto

    1979-07-01

    This work presents results of non destructive mass analysis of natural uranium by the pulsed source technique. Fissioning is produced by irradiating the test sample with pulses of 14 MeV neutrons and the uranium mass is calculated on a relative scale from the measured emission of delayed neutrons. Individual measurements were normalised against the integral counts of a scintillation detector measuring the 14 MeV neutron intensity. Delayed neutrons were measured using a specially constructed slab detector operated in anti synchronism with the fast pulsed source. The 14 MeV neutrons were produced via the T(d,n) {sup 4}He reaction using a 400 kV Van de Graaff accelerated operated at 200 kV in the pulsed source mode. Three types of sample were analysed, namely: discs of metallic uranium, pellets of sintered uranium oxide and plates of uranium aluminium alloy sandwiched between aluminium. These plates simulated those of Material Testing Reactor fuel elements. Results of measurements were reproducible to within an overall error in the range 1.6 to 3.9%; the specific error depending on the shape, size and mass of the sample. (author)

  13. Experimental design and optimization of leaching process for recovery of valuable chemical elements (U, La, V, Mo, Yb and Th) from low-grade uranium ore

    Energy Technology Data Exchange (ETDEWEB)

    Zakrzewska-Koltuniewicz, Grażyna, E-mail: g.zakrzewska@ichtj.waw.pl [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland); Herdzik-Koniecko, Irena [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland); Cojocaru, Corneliu [Institute of Macromolecular Chemistry “Petru Poni”, Aleea Grigore Ghica Voda, nr. 41A, 700487 Iasi (Romania); Chajduk, Ewelina [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland)

    2014-06-30

    Highlights: • The experimental design for optimization of leaching process of uranium from low-grade ores was applied. • Multi-objective optimization method based on desirability approach was employed. • The recovery of associated metals like vanadium, molybdenum and lanthanides was considered. • The effects of factors were identified by 3-D surface plots. • The optimum condition for valuable metals: P = 5 bar, T = 120 °C and t = 90 min has been determined. - Abstract: The paper deals with experimental design and optimization of leaching process of uranium and associated metals from low-grade, Polish ores. The chemical elements of interest for extraction from the ore were U, La, V, Mo, Yb and Th. Sulphuric acid has been used as leaching reagent. Based on the design of experiments the second-order regression models have been constructed to approximate the leaching efficiency of elements. The graphical illustrations using 3-D surface plots have been employed in order to identify the main, quadratic and interaction effects of the factors. The multi-objective optimization method based on desirability approach has been applied in this study. The optimum condition have been determined as P = 5 bar, T = 120 °C and t = 90 min. Under these optimal conditions, the overall extraction performance is 81.43% (for U), 64.24% (for La), 98.38% (for V), 43.69% (for Yb) and 76.89% (for Mo) and 97.00% (for Th)

  14. Uranium: myths and realities the depleted uranium; Uranio: Mitos y realidades. El caso del uranio emprobrecido

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, G.

    2001-07-01

    Uranium is an element whose name causes worry. The uranium properties are very unknown for people. However the element plays an important roll in the Earth as responsible of numerous natural phenomena, which are vital for life evolution. An example of the low knowledge about uranium has been the Balkan syndrome. A relation between cancers and the use of depleted uranium in ammunition in the Balkan War has been pretended to be established. From the beginning, this hypothesis could have been discarded as it has been confirmed and stated in recent reports of UNEP Commissions who have studied this matter. (Author)

  15. Natural Origin Lycopene and Its "Green" Downstream Processing.

    Science.gov (United States)

    Papaioannou, Emmanouil H; Liakopoulou-Kyriakides, Maria; Karabelas, Anastasios J

    2016-01-01

    Lycopene is an abundant natural carotenoid pigment with several biological functions (well-known for its antioxidant properties) which is under intensive investigation in recent years. Lycopene chemistry, its natural distribution, bioavailability, biological significance, and toxicological effects are briefly outlined in the first part of this review. The second, major part, deals with various modern downstream processing techniques, which are assessed in order to identify promising approaches for the recovery of lycopene and of similar lipophilic compounds. Natural lycopene is synthesized in plants and by microorganisms, with main representatives of these two categories (for industrial production) tomato and its by-products and the fungus Blakeslea trispora, respectively. Currently, there is a great deal of effort to develop efficient downstream processing for large scale production of natural-origin lycopene, with trends strongly indicating the necessity for "green" and mild extraction conditions. In this review, emphasis is placed on final product safety and ecofriendly processing, which are expected to totally dominate in the field of natural-origin lycopene extraction and purification.

  16. Natural language processing and the Now-or-Never bottleneck.

    Science.gov (United States)

    Gómez-Rodríguez, Carlos

    2016-01-01

    Researchers, motivated by the need to improve the efficiency of natural language processing tools to handle web-scale data, have recently arrived at models that remarkably match the expected features of human language processing under the Now-or-Never bottleneck framework. This provides additional support for said framework and highlights the research potential in the interaction between applied computational linguistics and cognitive science.

  17. Using complex resistivity imaging to infer biogeochemical processes associated with bioremediation of a uranium-contaminated aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Orozco, A. Flores; Williams, K.H.; Long, P.E.; Hubbard, S.S.; Kemna, A.

    2011-04-01

    Experiments at the Department of Energy's Rifle Integrated Field Research Challenge (IFRC) site near Rifle, Colorado (USA) have demonstrated the ability to remove uranium from groundwater by stimulating the growth and activity of Geobacter species through acetate amendment. Prolonging the activity of these strains in order to optimize uranium bioremediation has prompted the development of minimally-invasive and spatially-extensive monitoring methods diagnostic of their in situ activity and the end products of their metabolism. Here we demonstrate the use of complex resistivity imaging for monitoring biogeochemical changes accompanying stimulation of indigenous aquifer microorganisms during and after a prolonged period (100+ days) of acetate injection. A thorough raw-data statistical analysis of discrepancies between normal and reciprocal measurements and incorporation of a new power-law phase-error model in the inversion were used to significantly improve the quality of the resistivity phase images over those obtained during previous monitoring experiments at the Rifle IRFC site. The imaging results reveal spatiotemporal changes in the phase response of aquifer sediments, which correlate with increases in Fe(II) and precipitation of metal sulfides (e.g., FeS) following the iterative stimulation of iron and sulfate reducing microorganism. Only modest changes in resistivity magnitude were observed over the monitoring period. The largest phase anomalies (>40 mrad) were observed hundreds of days after halting acetate injection, in conjunction with accumulation of Fe(II) in the presence of residual FeS minerals, reflecting preservation of geochemically reduced conditions in the aquifer - a prerequisite for ensuring the long-term stability of immobilized, redox-sensitive contaminants, such as uranium.

  18. Using complex resistivity imaging to infer biogeochemical processes associated with bioremediation of an uranium-contaminated aquifer

    Science.gov (United States)

    Flores Orozco, AdriáN.; Williams, Kenneth H.; Long, Philip E.; Hubbard, Susan S.; Kemna, Andreas

    2011-09-01

    Experiments at the Department of Energy's Integrated Field Research Challenge (IFRC) site near Rifle, Colorado, have demonstrated the ability to remove uranium from groundwater by stimulating the growth and activity of Geobacter species through acetate amendment. Prolonging the activity of these strains in order to optimize uranium bioremediation has prompted the development of minimally invasive and spatially extensive monitoring methods diagnostic of their in situ activity and the end products of their metabolism. Here we demonstrate the use of complex resistivity imaging for monitoring biogeochemical changes accompanying stimulation of indigenous aquifer microorganisms during and after a prolonged period (100+ days) of acetate injection. A thorough raw data statistical analysis of discrepancies between normal and reciprocal measurements and incorporation of a new power law phase-error model in the inversion were used to significantly improve the quality of the resistivity phase images over those obtained during previous monitoring experiments at the Rifle IFRC site. The imaging results reveal spatiotemporal changes in the phase response of aquifer sediments, which correlate with increases in Fe(II) and precipitation of metal sulfides (e.g., FeS) following the iterative stimulation of iron and sulfate-reducing microorganisms. Only modest changes in resistivity magnitude were observed over the monitoring period. The largest phase anomalies (>40 mrad) were observed hundreds of days after halting acetate injection, in conjunction with accumulation of Fe(II) in the presence of residual FeS minerals, reflecting preservation of geochemically reduced conditions in the aquifer, a prerequisite for ensuring the long-term stability of immobilized, redox-sensitive contaminants such as uranium.

  19. Natural Language Processing Neural Network Considering Deep Cases

    Science.gov (United States)

    Sagara, Tsukasa; Hagiwara, Masafumi

    In this paper, we propose a novel neural network considering deep cases. It can learn knowledge from natural language documents and can perform recall and inference. Various techniques of natural language processing using Neural Network have been proposed. However, natural language sentences used in these techniques consist of about a few words, and they cannot handle complicated sentences. In order to solve these problems, the proposed network divides natural language sentences into a sentence layer, a knowledge layer, ten kinds of deep case layers and a dictionary layer. It can learn the relations among sentences and among words by dividing sentences. The advantages of the method are as follows: (1) ability to handle complicated sentences; (2) ability to restructure sentences; (3) usage of the conceptual dictionary, Goi-Taikei, as the long term memory in a brain. Two kinds of experiments were carried out by using goo dictionary and Wikipedia as knowledge sources. Superior performance of the proposed neural network has been confirmed.

  20. Recovery of uranium and plutonium from Redox off-standard aqueous waste streams

    Energy Technology Data Exchange (ETDEWEB)

    Holm, C.H.; Matheson, A.R.

    1949-12-31

    In the operation of countercurrent extraction columns as in the Redox process, it is possible, and probable, that from unexpected behaviour of a column, operator error, colloid formation, etc., there will result from time to time excessive losses of uranium and plutonium in the overall process. These losses will naturally accumulate in the waste streams, particularly in the aqueous waste streams. If the loss is excessively high, and such lost material can be recovered by some additional method, then if economical and within reason, the recovered materials ran be returned to a ISF column for further processing. The objective of this work has been to develop such a method to recover uranium and plutonium from such off-standard waste streams in a form whereby the uranium send plutonium can be returned to the process line and subsequently purified and separated.

  1. Recurrent Artificial Neural Networks and Finite State Natural Language Processing.

    Science.gov (United States)

    Moisl, Hermann

    It is argued that pessimistic assessments of the adequacy of artificial neural networks (ANNs) for natural language processing (NLP) on the grounds that they have a finite state architecture are unjustified, and that their adequacy in this regard is an empirical issue. First, arguments that counter standard objections to finite state NLP on the…

  2. Exploring the nature of facial affect processing deficits in schizophrenia.

    NARCIS (Netherlands)

    Wout, M. van 't; Aleman, A.; Kessels, R.P.C.; Cahn, W.; Haan, E.H.F. de; Kahn, R.S.

    2007-01-01

    Schizophrenia has been associated with deficits in facial affect processing, especially negative emotions. However, the exact nature of the deficit remains unclear. The aim of the present study was to investigate whether schizophrenia patients have problems in automatic allocation of attention as we

  3. Exploring the nature of facial affect processing deficits in schizophrenia

    NARCIS (Netherlands)

    Wout, Mascha van 't; Aleman, Andre; Kessels, Roy P. C.; Cahn, Wiepke; Haan, Edward H. F. de; Kahn, Rene S.

    2007-01-01

    Schizophrenia has been associated with deficits in facial affect processing, especially negative emotions. However, the exact nature of the deficit remains unclear. The aim of the present study was to investigate whether schizophrenia patients have problems in automatic allocation of attention as we

  4. Research at Yale in Natural Language Processing. Research Report #84.

    Science.gov (United States)

    Schank, Roger C.

    This report summarizes the capabilities of five computer programs at Yale that do automatic natural language processing as of the end of 1976. For each program an introduction to its overall intent is given, followed by the input/output, a short discussion of the research underlying the program, and a prognosis for future development. The programs…

  5. Advanced Natural Language Processing and Temporal Mining for Clinical Discovery

    Science.gov (United States)

    Mehrabi, Saeed

    2016-01-01

    There has been vast and growing amount of healthcare data especially with the rapid adoption of electronic health records (EHRs) as a result of the HITECH act of 2009. It is estimated that around 80% of the clinical information resides in the unstructured narrative of an EHR. Recently, natural language processing (NLP) techniques have offered…

  6. Uranium Mill Tailings Remedial Action Project surface project management plan

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    This Project Management Plan describes the planning, systems, and organization that shall be used to manage the Uranium Mill Tailings Remedial Action Project (UMTRA). US DOE is authorized to stabilize and control surface tailings and ground water contamination at 24 inactive uranium processing sites and associated vicinity properties containing uranium mill tailings and related residual radioactive materials.

  7. Illicit Trafficking of Natural Radionuclides

    Science.gov (United States)

    Friedrich, Steinhäusler; Lyudmila, Zaitseva

    2008-08-01

    Natural radionuclides have been subject to trafficking worldwide, involving natural uranium ore (U 238), processed uranium (yellow cake), low enriched uranium (20% U 235), radium (Ra 226), polonium (Po 210), and natural thorium ore (Th 232). An important prerequisite to successful illicit trafficking activities is access to a suitable logistical infrastructure enabling an undercover shipment of radioactive materials and, in case of trafficking natural uranium or thorium ore, capable of transporting large volumes of material. Covert en route diversion of an authorised uranium transport, together with covert diversion of uranium concentrate from an operating or closed uranium mines or mills, are subject of case studies. Such cases, involving Israel, Iran, Pakistan and Libya, have been analyzed in terms of international actors involved and methods deployed. Using international incident data contained in the Database on Nuclear Smuggling, Theft and Orphan Radiation Sources (DSTO) and international experience gained from the fight against drug trafficking, a generic Trafficking Pathway Model (TPM) is developed for trafficking of natural radionuclides. The TPM covers the complete trafficking cycle, ranging from material diversion, covert material transport, material concealment, and all associated operational procedures. The model subdivides the trafficking cycle into five phases: (1) Material diversion by insider(s) or initiation by outsider(s); (2) Covert transport; (3) Material brokerage; (4) Material sale; (5) Material delivery. An Action Plan is recommended, addressing the strengthening of the national infrastructure for material protection and accounting, development of higher standards of good governance, and needs for improving the control system deployed by customs, border guards and security forces.

  8. Mitigating Uranium in Ground Water: Prospects and Limitations

    OpenAIRE

    Noubactep, C.; Meinrath, G.; P. Dietrich; Merkel, B.

    2003-01-01

    Removal of uranium(VI) by zero-valent iron (ZVI) has been suggested as a feasible pathway to control uranium contaminations in seepage waters. Available information in literature however presents discrepant evidence on the process responsible for the mitigation effect. On basis of an EH-pH diagram of uranium and iron it is outlined that these discrepancies may be explained by the aqueous chemistry of uranium and iron. Additional effects contributing to the complexity of the sys...

  9. Through the explanatory process in natural history and ecology.

    Science.gov (United States)

    Mariani, Simone

    2008-01-01

    In this paper I will deal with the explanatory process used in natural history and ecology. I argue that the development of knowledge in natural history and descriptive ecology is the result of a bottom-up process, which is mainly empirical and progresses continuously from entity perception to theory construction. I consider the role of observation in the development of abstract images of entities, patterns, and processes through concepts and theories from a "simple" cognitive point of view and without regard for computational aspects. I analyze whether natural history provides "real" scientific explanation or just mere observation of facts. I later discuss the role of principles and laws in the explanation of observed regularities and accidents and the importance of prediction. I use the study of the larvae of sponges to describe the process because they represent a good example of past and current scientific method. My main argument is pragmatic being that the only relevant matters of the explanatory process are the perspective from which we observe the facts, the categorization methods we are using, and an acknowledgement of their scientific rigor. We need to advance in our epistemology in order to capture all the different meanings that the word "science" has acquired rather than sticking to one dominated by currently accepted methodologies.

  10. Analysis of uranium isotope separation by redox chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Fujine, S.; Naruse, Y.; Shiba, K.

    1983-09-01

    Uranium isotope separation by redox chromatography is analytically studied. The periodic withdrawal of products and tails and the introduction of natural feed are simulated on the assumption of a square cascade for a uranium adsorption band. The influences on the separative power and the lead time until product withdrawal are investigated by varying the magnitude of the isotope separation factor, uranium band length, tails concentration, and so on. Simulating calculations indicate that using ion-exchange resins to achieve uranium isotope separation requires a very long lead time for the production of highly enriched uranium.

  11. Modeling Uranium Transport in Koongarra, Australia: The Effect of a Moving Weathering Zone

    OpenAIRE

    2001-01-01

    Natural analogues are an important source of long-term data and may be viewed as naturally occurring experiments that often include processes, phenomena, and scenarios that are important to nuclear waste disposal safety assessment studies. The Koongarra uranium deposit in the Alligator Rivers region of Australia is one of the best-studied natural analogue sites. The deposit has been subjected to chemical weathering over several million years, during which many climatological, hydrological, an...

  12. THE WATER FROM NATURE AND THE EROSION PROCESS

    Directory of Open Access Journals (Sweden)

    G. PANDI

    2015-03-01

    Full Text Available The water from nature and the erosion process. Studying earth's surface erosion process is necessary for practical reasons. The theoretical approach requires knowledge of the alluvial system’s structure and operation as the cascade sequence of fluvial system’s mass and energy. Geosystem research methodology requires that the water energy and the role of adjacent surface must be expressed. The expression of water power can be grouped according to the shape of movement and action in the basin. A particular, important case is the energy variation in a basin-slope. An important role in energy expressions is considering the existence in nature of biphasic fluid - water as dispersion phase and solid particles as dispersed phase. The role of the adjacent surface is taken into account by using the erosion resistance indicator, which is calculated using the indicator of geological resistance and the indicator of plant protection. The evolution of natural systems, therefore of river basins too, leads to energy diminishing, thus affecting their dynamic balance. This can be expressed using the concept of entropy. Although erosion processes are usual natural phenomena for the evolution of river basins, they induce significant risks in certain circumstances. Depending on the circulated water energies, water basins can be ranked in terms of potential risks.

  13. Uranium industry annual 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-05

    The Uranium Industry Annual 1994 (UIA 1994) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing during that survey year. The UIA 1994 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. It contains data for the 10-year period 1985 through 1994 as collected on the Form EIA-858, ``Uranium Industry Annual Survey.`` Data collected on the ``Uranium Industry Annual Survey`` (UIAS) provide a comprehensive statistical characterization of the industry`s activities for the survey year and also include some information about industry`s plans and commitments for the near-term future. Where aggregate data are presented in the UIA 1994, care has been taken to protect the confidentiality of company-specific information while still conveying accurate and complete statistical data. A feature article, ``Comparison of Uranium Mill Tailings Reclamation in the United States and Canada,`` is included in the UIA 1994. Data on uranium raw materials activities including exploration activities and expenditures, EIA-estimated resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities, including purchases of uranium and enrichment services, and uranium inventories, enrichment feed deliveries (actual and projected), and unfilled market requirements are shown in Chapter 2.

  14. Uranium Provinces in China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Three uranium provinces are recognized in China, the Southeast China uranium province, the Northeast China-lnner Mongolia uranium province and the Northwest China (Xinjiang) uranium province. The latter two promise good potential for uranium resources and are major exploration target areas in recent years. There are two major types of uranium deposits: the Phanerozoic hydrothermal type (vein type) and the Meso-Cenozoic sandstone type in different proportions in the three uranium provinces. The most important reason or prerequisite for the formation of these uranium provinces is that Precambrian uranium-enriched old basement or its broken parts (median massifs) exists or once existed in these regions, and underwent strong tectonomagmatic activation during Phanerozoic time. Uranium was mobilized from the old basement and migrated upwards to the upper structural level together with the acidic magma originating from anatexis and the primary fluids, which were then mixed with meteoric water and resulted in the formation of Phanerozoic hydrothermal uranium deposits under extensional tectonic environments. Erosion of uraniferous rocks and pre-existing uranium deposits during the Meso-Cenozoic brought about the removal of uranium into young sedimentary basins. When those basins were uplifted and slightly deformed by later tectonic activity, roll-type uranium deposits were formed as a result of redox in permeable sandstone strata.

  15. Uranium industry annual 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-04-22

    The Uranium Industry Annual 1998 (UIA 1998) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing. It contains data for the period 1989 through 2008 as collected on the Form EIA-858, ``Uranium Industry Annual Survey.`` Data provides a comprehensive statistical characterization of the industry`s activities for the survey year and also include some information about industry`s plans and commitments for the near-term future. Data on uranium raw materials activities for 1989 through 1998, including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment, are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2008, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, and uranium inventories, are shown in Chapter 2. The methodology used in the 1998 survey, including data edit and analysis, is described in Appendix A. The methodologies for estimation of resources and reserves are described in Appendix B. A list of respondents to the ``Uranium Industry Annual Survey`` is provided in Appendix C. The Form EIA-858 ``Uranium Industry Annual Survey`` is shown in Appendix D. For the readers convenience, metric versions of selected tables from Chapters 1 and 2 are presented in Appendix E along with the standard conversion factors used. A glossary of technical terms is at the end of the report. 24 figs., 56 tabs.

  16. No fluorinated compounds in the uranium conversion process: risk analysis and proposition of pictograms; Os compostos nao fluorados nos processos da conversao do uranio: analise de riscos e proposicao de pictogramas

    Energy Technology Data Exchange (ETDEWEB)

    Jeronimo, Adroaldo Clovis; Oliveira, Wagner dos Santos, E-mail: acejota18@yahoo.com.br, E-mail: oliveira@feq.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Quimica; Aquino, Afonso Rodrigues de, E-mail: araquino@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-03-15

    The plants comprising the chemical conversion of uranium, which are part of the nuclear fuel cycle, present some risks, among others, because are associated with the non-fluorinated compounds handled in these processes. This study is the analysis of the risks associated with these compounds, i e, the non-fluorinated reactants and products, handled in different chemical processing plants, which include the production of uranium hexafluoride, while emphasizing the responsibilities and actions that fit to the chemical engineer with regard to minimizing risks during the various stages. The work is based on the experience gained during the development and mastery of the technology of production of uranium hexafluoride, the IPEN/ CNEN-SP, during the '80s, with the support of COPESP -Navy of Brazil. (author)

  17. HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING

    Energy Technology Data Exchange (ETDEWEB)

    Girish Srinivas; Steven C. Gebhard; David W. DeBerry

    2001-05-01

    This first quarter report of 2001 describes progress on a project funded by the U.S. Department of Energy (DOE) to test a hybrid sulfur recovery process for natural gas upgrading. The process concept represents a low cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both on-shore and offshore applications. CrystaSulf{trademark} (service mark of Gas Research Institute) is a new nonaqueous sulfur recovery process that removes hydrogen sulfide (H{sub 2}S) from gas streams and converts it into elemental sulfur. CrystaSulf features high sulfur recovery similar to aqueous-iron liquid redox sulfur recovery processes, but differs from the aqueous processes in that CrystaSulf controls the location where elemental sulfur particles are formed. In the hybrid process, approximately 1/3 of the total H{sub 2}S in the natural gas is first oxidized to SO{sub 2} at low temperatures over a heterogeneous catalyst. Low temperature oxidation is done so that the H{sub 2}S can be oxidized in the presence of methane and other hydrocarbons without oxidation of the hydrocarbons. The project involves the development of a catalyst using laboratory/bench-scale catalyst testing, and then demonstration of the catalyst at CrystaTech's pilot plant in west Texas. During this reporting periods new catalyst formulations were tested. The experiments showed that the newest catalyst has slightly better performance, but catalyst TDA No.2 is still superior overall for use with the hybrid CrystaSulf process due to lower costs. Plans for catalyst pelletization and continued testing are described.

  18. Evaluation of the effectiveness of the filtration leaching for uranium recovery from uranium ore

    OpenAIRE

    2015-01-01

    The physical and chemical processes taking place in filtration leaching of uranium from uranium ore sample by sulphuric acid solution have been studied by modern physico-chemical methods (X-ray diffraction, scanning electron spectroscopy, electron probe microanalysis, optical emission spectroscope, ICP OES). Column leaching test was carried out for ore samples obtained from a uranium in-situ leaching (ISL) mining site using deluted sulphuricacid to study the evolution of various elements conc...

  19. Natural uranium and strontium isotope tracers of water sources and surface water-groundwater interactions in arid wetlands: Pahranagat Valley, Nevada, USA

    Science.gov (United States)

    Paces, James B.; Wurster, Frederic C.

    2014-01-01

    Near-surface physical and chemical process can strongly affect dissolved-ion concentrations and stable isotope compositions of water in wetland settings, especially under arid climate conditions. In contrast, heavy radiogenic isotopes of strontium (87Sr/86Sr) and uranium (234U/238U) remain largely unaffected and can be used to help identify unique signatures from different sources and quantify end-member mixing that would otherwise be difficult to determine. The utility of combined Sr and U isotopes are demonstrated in this study of wetland habitats on the Pahranagat National Wildlife Refuge, which depend on supply from large-volume springs north of the Refuge, and from small-volume springs and seeps within the Refuge. Water budgets from these sources have not been quantified previously. Evaporation, transpiration, seasonally variable surface flow, and water management practices complicate the use of conventional methods for determining source contributions and mixing relations. In contrast, 87Sr/86Sr and 234U/238U remain unfractionated under these conditions, and compositions at a given site remain constant. Differences in Sr- and U-isotopic signatures between individual sites can be related by simple two- or three-component mixing models. Results indicate that surface flow constituting the Refuge’s irrigation source consists of a 65:25:10 mixture of water from two distinct regionally sourced carbonate aquifer springs, and groundwater from locally sourced volcanic aquifers. Within the Refuge, contributions from the irrigation source and local groundwater are readily determined and depend on proximity to those sources as well as water management practices.

  20. Electroformation of uranium hemispherical shells

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, S.L.; Redey, L.; Vandegrift, G.F.; Vissers, D.R.

    1989-11-01

    This effort was directed at developing an electrochemical process for forming uniform and dendrite-free deposits of uranium from molten salts. This process is to be used for the electroformation of free-standing hemispherical shells of uranium for nuclear applications. Electrodeposition of uranium onto a substrate was accomplished with a fused chloride mixture containing 42 wt% UCl{sub 3} and a fused chloride-fluoride mixture containing 4 wt % UF{sub 4}. Under pulsed potential control at 504{degree}C, the chloride-fluoride mixture yielded the widest range of plating conditions for which dendrites could be avoided. Bipolar current pulse plating with both electrolytes gave good results, and successful application of this technique to a large tubular cathode has been demonstrated. 24 refs., 10 figs.

  1. The nature of innovation processes in Facility Management services

    DEFF Research Database (Denmark)

    Nardelli, Giulia

    Purpose: This work investigates the dynamics of interaction between stakeholders of Facilities Management (FM) innovation and improvement processes. The aim is to understand how the complex value chain of FM services influences innovation processes within this field. Theory: This study combines...... theories on innovation in services with research focused on the empirical field of FM. More specifically, the analytical framework for this study applies the differentiation between reactive and proactive innovation processes by Toivonen and Tuominen (2009) to the value chain identified by Coenen...... has a threefold impact on the nature of innovation processes within this field. Firstly, end-users of FM services are usually not involved in innovation processes, although they might sometimes play a role as initial drivers. Secondly, FM services are intangible but more easily reproducible than other...

  2. Variations in the uranium isotopic compositions of uranium ores from different types of uranium deposits

    Science.gov (United States)

    Uvarova, Yulia A.; Kyser, T. Kurt; Geagea, Majdi Lahd; Chipley, Don

    2014-12-01

    precipitation in the form of U6+ minerals. The δ238U values of uranium ore minerals from a variety of deposits are controlled by the isotopic signature of the uranium source, the efficiency of uranium reduction in the case of UO2 systems, and the degree to which uranium was previously removed from the fluid, with less influence from temperature of ore formation and later alteration of the ore. Uranium isotopes are potentially superb tracers of redox in natural systems.

  3. The growth process of natural poplar-birch forests

    Institute of Scientific and Technical Information of China (English)

    LAN Shibo; LUO Xu; LUO Yuliang

    2006-01-01

    With a combination of permanent and temporary sample plots,we investigated the growth conditions of natural poplar-birch forests.The forests were divided into four site classes,using statistical and analytical techniques in a quantitative model,in descending order where site class I was the best.On this basis,the growth of natural poplar-birch forests in the different site classes was studied.The growth processes of height and diameter at breast height were divided into three stages:a fast growing period,a stable growing period and a slow growing period.Results of this study provide a theoretical basis for the directive cultivation of natural poplar-birch forests.

  4. An overview of computer-based natural language processing

    Science.gov (United States)

    Gevarter, W. B.

    1983-01-01

    Computer based Natural Language Processing (NLP) is the key to enabling humans and their computer based creations to interact with machines in natural language (like English, Japanese, German, etc., in contrast to formal computer languages). The doors that such an achievement can open have made this a major research area in Artificial Intelligence and Computational Linguistics. Commercial natural language interfaces to computers have recently entered the market and future looks bright for other applications as well. This report reviews the basic approaches to such systems, the techniques utilized, applications, the state of the art of the technology, issues and research requirements, the major participants and finally, future trends and expectations. It is anticipated that this report will prove useful to engineering and research managers, potential users, and others who will be affected by this field as it unfolds.

  5. The Legacy of Uranium Development on or Near Indian Reservations and Health Implications Rekindling Public Awareness

    Directory of Open Access Journals (Sweden)

    Anita Moore-Nall

    2015-02-01

    Full Text Available Uranium occurrence and development has left a legacy of long-lived health effects for many Native Americans and Alaska Natives in the United States. Some Native American communities have been impacted by processing and development while others are living with naturally occurring sources of uranium. The uranium production peak spanned from approximately 1948 to the 1980s. Thousands of mines, mainly on the Colorado Plateau, were developed in the western U.S. during the uranium boom. Many of these mines were abandoned and have not been reclaimed. Native Americans in the Colorado Plateau area including the Navajo, Southern Ute, Ute Mountain, Hopi, Zuni, Laguna, Acoma, and several other Pueblo nations, with their intimate knowledge of the land, often led miners to uranium resources during this exploration boom. As a result of the mining activity many Indian Nations residing near areas of mining or milling have had and continue to have their health compromised. This short review aims to rekindle the public awareness of the plight of Native American communities living with the legacy of uranium procurement, including mining, milling, down winders, nuclear weapon development and long term nuclear waste storage.

  6. Uranium extraction by complexation with siderophores

    Science.gov (United States)

    Bahamonde Castro, Cristina

    One of the major concerns of energy production is the environmental impact associated with the extraction of natural resources. Nuclear energy fuel is obtained from uranium, an abundant and naturally occurring element in the environment, but the currently used techniques for uranium extraction leave either a significant fingerprint (open pit mines) or a chemical residue that alters the pH of the environment (acid or alkali leaching). It is therefore clear that a new and greener approach to uranium extraction is needed. Bioleaching is one potential alternative. In bioleaching, complexants naturally produced from fungi or bacteria may be used to extract the uranium. In the following research, the siderophore enterobactin, which is naturally produced by bacteria to extract and solubilize iron from the environment, is evaluated to determine its potential for complexing with uranium. To determine whether enterobactin could be used for uranium extraction, its acid dissociation and its binding strength with the metal of interest must be determined. Due to the complexity of working with radioactive materials, lanthanides were used as analogs for uranium. In addition, polyprotic acids were used as structural and chemical analogs for the siderophore during method development. To evaluate the acid dissociation of enterobactin and the subsequent binding constants with lanthanides, three different analytical techniques were studied including: potentiometric titration, UltraViolet Visible (UV-Vis) spectrophotometry and Isothermal Titration Calorimetry (ITC). After evaluation of three techniques, a combination of ITC and potentiometric titrations was deemed to be the most viable way for studying the siderophore of interest. The results obtained from these studies corroborate the ideal pH range for enterobactin complexation to the lanthanide of interest and pave the way for determining the strength of complexation relative to other naturally occurring metals. Ultimately, this

  7. Fabrication of Natural Uranium UO2 Disks (Phase II): Texas A&M Work for Others Summary Document

    Energy Technology Data Exchange (ETDEWEB)

    Gerczak, Tyler J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baldwin, Charles A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Schmidlin, Joshua E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Henry, Jr, John James [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-28

    The steps to fabricate natural UO2 disks for an irradiation campaign led by Texas A&M University are outlined. The process was initiated with stoichiometry adjustment of parent, U3O8 powder. The next stage of sample preparation involved exploratory pellet pressing and sintering to achieve the desired natural UO2 pellet densities. Ideal densities were achieved through the use of a bimodal powder size blend. The steps involved with disk fabrication are also presented, describing the coring and thinning process executed to achieve final dimensionality.

  8. Using natural language processing techniques to inform research on nanotechnology

    Directory of Open Access Journals (Sweden)

    Nastassja A. Lewinski

    2015-07-01

    Full Text Available Literature in the field of nanotechnology is exponentially increasing with more and more engineered nanomaterials being created, characterized, and tested for performance and safety. With the deluge of published data, there is a need for natural language processing approaches to semi-automate the cataloguing of engineered nanomaterials and their associated physico-chemical properties, performance, exposure scenarios, and biological effects. In this paper, we review the different informatics methods that have been applied to patent mining, nanomaterial/device characterization, nanomedicine, and environmental risk assessment. Nine natural language processing (NLP-based tools were identified: NanoPort, NanoMapper, TechPerceptor, a Text Mining Framework, a Nanodevice Analyzer, a Clinical Trial Document Classifier, Nanotoxicity Searcher, NanoSifter, and NEIMiner. We conclude with recommendations for sharing NLP-related tools through online repositories to broaden participation in nanoinformatics.

  9. Applications of Natural Language Processing in Biodiversity Science

    Directory of Open Access Journals (Sweden)

    Anne E. Thessen

    2012-01-01

    A computer can handle the volume but cannot make sense of the language. This paper reviews and discusses the use of natural language processing (NLP and machine-learning algorithms to extract information from systematic literature. NLP algorithms have been used for decades, but require special development for application in the biological realm due to the special nature of the language. Many tools exist for biological information extraction (cellular processes, taxonomic names, and morphological characters, but none have been applied life wide and most still require testing and development. Progress has been made in developing algorithms for automated annotation of taxonomic text, identification of taxonomic names in text, and extraction of morphological character information from taxonomic descriptions. This manuscript will briefly discuss the key steps in applying information extraction tools to enhance biodiversity science.

  10. Natural history collections as windows on evolutionary processes.

    Science.gov (United States)

    Holmes, Michael W; Hammond, Talisin T; Wogan, Guinevere O U; Walsh, Rachel E; LaBarbera, Katie; Wommack, Elizabeth A; Martins, Felipe M; Crawford, Jeremy C; Mack, Katya L; Bloch, Luke M; Nachman, Michael W

    2016-02-01

    Natural history collections provide an immense record of biodiversity on Earth. These repositories have traditionally been used to address fundamental questions in biogeography, systematics and conservation. However, they also hold the potential for studying evolution directly. While some of the best direct observations of evolution have come from long-term field studies or from experimental studies in the laboratory, natural history collections are providing new insights into evolutionary change in natural populations. By comparing phenotypic and genotypic changes in populations through time, natural history collections provide a window into evolutionary processes. Recent studies utilizing this approach have revealed some dramatic instances of phenotypic change over short timescales in response to presumably strong selective pressures. In some instances, evolutionary change can be paired with environmental change, providing a context for potential selective forces. Moreover, in a few cases, the genetic basis of phenotypic change is well understood, allowing for insight into adaptive change at multiple levels. These kinds of studies open the door to a wide range of previously intractable questions by enabling the study of evolution through time, analogous to experimental studies in the laboratory, but amenable to a diversity of species over longer timescales in natural populations. © 2016 John Wiley & Sons Ltd.

  11. Evolutionary and geological factors controlling endogenic uranium mineralization and the potential for the discovery of new ore districts

    Science.gov (United States)

    Mashkovtsev, G. A.; Miguta, A. K.; Shchetochkin, V. N.

    2015-03-01

    The exhaustion of known surface and near-surface high-grade uranium deposits poses the serious problem of prospecting and exploration of new large endogenic deposits. A comparison of large data sets for endogenic deposits from the world's major uranium districts allowed the authors to develop an evolutionary geological model of large-scale uranium ore genesis, which reflects the succession and nature of preore, ore-forming, and post-ore processes. The study reveals a combination of general (recurrent) factors controlling the formation of ore districts with large-scale uranium mineralization regardless of the genesis and timing of the mineralization. At the same time, these factors depend on the regional setting and can vary considerably among deposits of the same type localized in different tectonic blocks with different characteristics and structural evolution. In connection with this, the exploration of major genetic types of deposits requires the application of specified criteria. Along with the consideration of the evolutionary geological model of ore formation, the study discusses a variety of tectono-magmatic, mineralogical, geochemical, radiogeochemical, and physicochemical factors and indications in three uranium districts (the Streltsovskoe, Elkon, and Central Ukrainian districts), which can form the basis for further uranium prospecting and exploration. Using a combination of favorable prerequisite conditions the study compares the possibilities for the discovery of large endogenic uranium deposits in several regions of Russia.

  12. The Theoretical Status of Ontologies in Natural Language Processing

    CERN Document Server

    Bateman, J A

    1997-01-01

    This paper discusses the use of `ontologies' in Natural Language Processing. It classifies various kinds of ontologies that have been employed in NLP and discusses various benefits and problems with those designs. Particular focus is then placed on experiences gained in the use of the Upper Model, a linguistically-motivated `ontology' originally designed for use with the Penman text generation system. Some proposals for further NLP ontology design criteria are then made.

  13. Artificial intelligence, expert systems, computer vision, and natural language processing

    Science.gov (United States)

    Gevarter, W. B.

    1984-01-01

    An overview of artificial intelligence (AI), its core ingredients, and its applications is presented. The knowledge representation, logic, problem solving approaches, languages, and computers pertaining to AI are examined, and the state of the art in AI is reviewed. The use of AI in expert systems, computer vision, natural language processing, speech recognition and understanding, speech synthesis, problem solving, and planning is examined. Basic AI topics, including automation, search-oriented problem solving, knowledge representation, and computational logic, are discussed.

  14. Rotating thermal flows in natural and industrial processes

    CERN Document Server

    Lappa, Marcello

    2012-01-01

    Rotating Thermal Flows in Natural and Industrial Processes provides the reader with a systematic description of the different types of thermal convection and flow instabilities in rotating systems, as present in materials, crystal growth, thermal engineering, meteorology, oceanography, geophysics and astrophysics. It expressly shows how the isomorphism between small and large scale phenomena becomes beneficial to the definition and ensuing development of an integrated comprehensive framework.  This allows the reader to understand and assimilate the underlying, quintessential mechanisms withou

  15. Artificial intelligence, expert systems, computer vision, and natural language processing

    Science.gov (United States)

    Gevarter, W. B.

    1984-01-01

    An overview of artificial intelligence (AI), its core ingredients, and its applications is presented. The knowledge representation, logic, problem solving approaches, languages, and computers pertaining to AI are examined, and the state of the art in AI is reviewed. The use of AI in expert systems, computer vision, natural language processing, speech recognition and understanding, speech synthesis, problem solving, and planning is examined. Basic AI topics, including automation, search-oriented problem solving, knowledge representation, and computational logic, are discussed.

  16. Investigations on uranium sorption on bentonite and montmorillonite, respectively, and uranium in environmental samples; Untersuchungen zur Uransorption an Bentonit bzw. Montmorillonit sowie von Uran in Umweltproben

    Energy Technology Data Exchange (ETDEWEB)

    Azeroual, Mohamed

    2010-09-22

    The geotechnical barrier is an important component of a geological repository and consists of compacted bentonite surrounding radioactive waste containers. Its most important functions are, to retard the radionuclide migration into the biosphere and to prevent groundwater contact with containers. lt is therefore of central importance to investigate the bentonite material on its capacity to sorb radionuclides under near-natural chemical and physical conditions. The purpose of this work was to study the adsorption of uranium(VI) on bentonit and on montmorillonite-standards at high uranium concentrations. Thereby, a special account was given to the calcium-uranyl-carbonate complexation, which leads to the formation of very stable and mobile uncharged Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} complex. Results of batch experiments showed that the dicalcium-uranyl-tricarbonate complexation lowers the uranium(VI) sorption on natural clay (bentonite) by a factor of up to 3. After 21 days of contact time, about 40 % and 20 % of the initial uranium(VI)concentration were sorbed on Na-bentonite and ea-bentonite, respectively, from a solution with Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} dominating the uranium(VI) speciation. On the contrary, about 55 % of the initial uranium(VI)-concentration were sorbed on thes clays from the solution, in which (UO{sub 2}){sub 2}CO{sub 3}(OH){sub 3}{sup -} complex dominated the uranium(VI) speciation. Thus uranium(VI) sorption is more strongly influenced by the solution composition than by bentonite type. Na-bentonite should be used instead of ea-bentonite as a geotechnical barrier, since calcium-uranyl-carbonate complexation may be a realistic scenario. Further SEM-EDX and HREM-EDX studies showed that uranium(VI) sorption occurred predominantly on montmorillonite, which is the main component of bentonite. Uranium(VI) sorption on bentonite's accessory Minerals (pyrite, calcite, mica, and feldspar) was not observed. Investigation of uranium

  17. Extraction of Textual Causal Relationships based on Natural Language Processing

    Directory of Open Access Journals (Sweden)

    Sepideh Jamshidi-Nejad

    2015-11-01

    Full Text Available Natural language processing is a highly important subcategory in the wide area of artificial intelligence. Employing appropriate computational algorithms on sophisticated linguistic operations is the aim of natural language processing to extract and create computational theories from languages. In order to achieve this goal, the knowledge of linguists is needed in addition to computer science. In the field of linguistics, the syntactic and semantic relation of words and phrases and the extraction of causation is very significant which the latter is an information retrieval challenge. Recently, there is an increased attention towards the automatic extraction of causation from textual data sets. Although, previous research extracted the casual relations from uninterrupted data sets by using knowledge-based inference technologies and manual coding. Recently, finding comprehensive approaches for detection and extractions of causal arguments is a research area in the field of natural language processing.In this paper, a three-stepped approach is established through which, the position of words with syntax trees is obtained by extracting causation from causal and non-causal sentences of Web text. The arguments of events were extracted according to the dependency tree of phrases implemented by Python packages. Then potential causal relations were extracted by the extraction of specific nodes of the tree. In the final step, a statistical model is introduced for measuring the potential causal relations. Experimental results and evaluations with Recall, Precision and F-measure metrics show the accuracy and efficiency of the suggested model.

  18. Pattern Recognition and Natural Language Processing: State of the Art

    Directory of Open Access Journals (Sweden)

    Mirjana Kocaleva

    2016-05-01

    Full Text Available Development of information technologies is growing steadily. With the latest software technologies development and application of the methods of artificial intelligence and machine learning intelligence embededs in computers, the expectations are that in near future computers will be able to solve problems themselves like people do. Artificial intelligence emulates human behavior on computers. Rather than executing instructions one by one, as theyare programmed, machine learning employs prior experience/data that is used in the process of system’s training. In this state of the art paper, common methods in AI, such as machine learning, pattern recognition and the natural language processing (NLP are discussed. Also are given standard architecture of NLP processing system and the level thatisneeded for understanding NLP. Lastly the statistical NLP processing and multi-word expressions are described.

  19. Uranium briquettes for irradiation target

    Energy Technology Data Exchange (ETDEWEB)

    Saliba-Silva, Adonis Marcelo; Garcia, Rafael Henrique Lazzari; Martins, Ilson Carlos; Carvalho, Elita Fontenele Urano de; Durazzo, Michelangelo, E-mail: saliba@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Direct irradiation on targets inside nuclear research or multiple purpose reactors is a common route to produce {sup 99}Mo-{sup 99m}Tc radioisotopes. Nevertheless, since the imposed limits to use LEU uranium to prevent nuclear armament production, the amount of uranium loaded in target meats has physically increased and new processes have been proposed for production. Routes using metallic uranium thin film and UAl{sub x} dispersion have been used for this purpose. Both routes have their own issues, either by bringing difficulties to disassemble the aluminum case inside hot cells or by generating great amount of alkaline radioactive liquid rejects. A potential route might be the dispersion of powders of LEU metallic uranium and nickel, which are pressed as a blend inside a die and followed by pulse electroplating of nickel. The electroplating provides more strength to the briquettes and creates a barrier for gas evolution during neutronic disintegration of {sup 235}U. A target briquette platted with nickel encapsulated in an aluminum case to be irradiated may be an alternative possibility to replace other proposed targets. This work uses pulse Ni-electroplating over iron powder briquette to simulate the covering of uranium by nickel. The following parameters were applied 10 times for each sample: 900Hz, -0.84A/square centimeters with duty cycle of 0.1 in Watts Bath. It also presented the optical microscopy analysis of plated microstructure section. (author)

  20. Determination of uranium transfer factors from soils contaminated with natural uranium along the Vereinigten Mulde in Zwickau; Bestimmung von Transferfaktoren von Uran aus natuerlich belasteten Boeden entlang der Zwickauer und Vereinigten Mulde

    Energy Technology Data Exchange (ETDEWEB)

    Brand, Andreas

    2011-07-01

    According to IAEA the food chain soil-plants-human is the predominant radionuclide ingestion path. The consumption of contaminated vegetarian food causes a continuous radiation exposure. In this context the problem of contaminated meadows in the Zwickauer and Vereinigten Mulde that is used for agriculture is of predominant interest. In this area intensive uranium mining has caused severe environmental contamination. The agricultural crop land and the grass land were studied with respect to the radionuclides U-238 and U-234. Following the radiochemical separation using ion chromatography the samples were analyzed by alpha-spectrometry. Compared to non-contaminated areas significant specific activities were measured. The transfer factors of the radionuclides U-238 and U-234 were determined for different plant parts. The transfer factors decrease with increasing radioactive contamination of the soils.

  1. Cathodoluminescence of uranium oxides

    Energy Technology Data Exchange (ETDEWEB)

    Winer, K.; Colmenares, C.; Wooten, F.

    1984-08-09

    The cathodoluminescence of uranium oxide surfaces prepared in-situ from clean uranium exposed to dry oxygen was studied. The broad asymmetric peak observed at 470 nm is attributed to F-center excitation.

  2. NSRR experiment with un-irradiated uranium-zirconium hydride fuel. Design, fabrication process and inspection data of test fuel rod

    Energy Technology Data Exchange (ETDEWEB)

    Sasajima, Hideo; Fuketa, Toyoshi; Ishijima, Kiyomi; Kuroha, Hiroshi; Ikeda, Yoshikazu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Aizawa, Keiichi

    1998-08-01

    An experiment plan is progressing in the Nuclear Safety Research Reactor (NSRR) to perform pulse-irradiation with uranium-zirconium hydride (U-ZrH{sub x}) fuel. This fuel is widely used in the training research and isotope production reactor of GA (TRIGA). The objectives of the experiment are to determine the fuel rod failure threshold and to investigate fuel behavior under simulated reactivity initiated accident (RIA) conditions. This report summarizes design, fabrication process and inspection data of the test fuel rods before pulse-irradiation. The experiment with U-ZrH{sub x} fuel will realize precise safety evaluation, and improve the TRIGA reactor performance. The data to be obtained in this program will also contribute development of next-generation TRIGA reactor and its safety evaluation. (author)

  3. Natural leathers from natural materials: progressing toward a new arena in leather processing.

    Science.gov (United States)

    Saravanabhavan, Subramani; Thanikaivelan, Palanisamy; Rao, Jonnalagadda Raghava; Nair, Balachandran Unni; Ramasami, Thirumalachari

    2004-02-01

    Globally, the leather industry is currently undergoing radical transformation due to pollution and discharge legislations. Thus, the leather industry is pressurized to look for cleaner options for processing the raw hides and skins. Conventional methods of pre-tanning, tanning and post-tanning processes are known to contribute more than 98% of the total pollution load from the leather processing. The conventional method of the tanning process involves the "do-undo" principle. Furthermore, the conventional methods employed in leather processing subject the skin/ hide to a wide variation in pH (2.8-13.0). This results in the emission of huge amounts of pollution loads such as BOD, COD, TDS, TS, sulfates, chlorides and chromium. In the approach illustrated here, the hair and flesh removal as well as fiber opening have been achieved using biocatalysts at pH 8.0, pickle-free natural tanning employing vegetable tannins, and post-tanning using environmentally friendly chemicals. Hence, this process involves dehairing, fiber opening, and pickle-free natural tanning followed by ecofriendly post-tanning. It has been found that the extent of hair removal and opening up of fiber bundles is comparable to that of conventionally processed leathers. This has been substantiated through scanning electron microscopic analysis and softness measurements. Performance of the leathers is shown to be on par with conventionally chrome-tanned leathers through physical and hand evaluation. The process also exhibits zero metal (chromium) discharge and significant reduction in BOD, COD, TDS, and TS loads by 83, 69, 96, and 96%, respectively. Furthermore, the developed process seems to be economically viable.

  4. Uranium industry annual 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    The Uranium Industry Annual 1995 (UIA 1995) provides current statistical data on the U.S. uranium industry`s activities relating to uranium raw materials and uranium marketing. The UIA 1995 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. It contains data for the period 1986 through 2005 as collected on the Form EIA-858, ``Uranium Industry Annual Survey``. Data collected on the ``Uranium Industry Annual Survey`` provide a comprehensive statistical characterization of the industry`s plans and commitments for the near-term future. Where aggregate data are presented in the UIA 1995, care has been taken to protect the confidentiality of company-specific information while still conveying accurate and complete statistical data. Data on uranium raw materials activities for 1986 through 1995 including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2005, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, uranium imports and exports, and uranium inventories are shown in Chapter 2. The methodology used in the 1995 survey, including data edit and analysis, is described in Appendix A. The methodologies for estimation of resources and reserves are described in Appendix B. A list of respondents to the ``Uranium Industry Annual Survey`` is provided in Appendix C. For the reader`s convenience, metric versions of selected tables from Chapters 1 and 2 are presented in Appendix D along with the standard conversion factors used. A glossary of technical terms is at the end of the report. 14 figs., 56 tabs.

  5. RECALIBRATION OF H CANYON ONLINE SPECTROPHOTOMETER AT EXTENDED URANIUM CONCENTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Lascola, R

    2008-10-29

    The H Canyon online spectrophotometers are calibrated for measurement of the uranium and nitric acid concentrations of several tanks in the 2nd Uranium Cycle.[1] The spectrometers, flow cells, and prediction models are currently optimized for a process in which uranium concentrations are expected to range from 0-15 g/L and nitric acid concentrations from 0.05-6 M. However, an upcoming processing campaign will involve 'Super Kukla' material, which has a lower than usual enrichment of fissionable uranium. Total uranium concentrations will be higher, spanning approximately 0-30 g/L U, with no change in the nitric acid concentrations. The new processing conditions require the installation of new flow cells with shorter path lengths. As the process solutions have a higher uranium concentration, the shorter path length is required to decrease the absorptivity to values closer to the optimal range for the instrument. Also, new uranium and nitric acid prediction models are required to span the extended uranium concentration range. The models will be developed for the 17.5 and 15.4 tanks, for which nitric acid concentrations will not exceed 1 M. The restricted acid range compared to the original models is anticipated to reduce the measurement uncertainty for both uranium and nitric acid. The online spectrophotometers in H Canyon Second Uranium Cycle were modified to allow measurement of uranium and nitric acid for the Super Kukla processing campaign. The expected uranium concentrations, which are higher than those that have been recently processed, required new flow cells with one-third the optical path length of the existing cells. Also, new uranium and nitric acid calibrations were made. The estimated reading uncertainties (2{sigma}) for Tanks 15.4 and 17.5 are {approx}5% for uranium and {approx}25% for nitric acid.

  6. An eco-friendly process for natural gas conversion

    Energy Technology Data Exchange (ETDEWEB)

    Yao, S.; Nakayama, A.; Suzuki, E. [Research Institute of Innovative Technology for the Earth, Kyoto (Japan). Catalysis Science Laboratory

    2001-07-01

    An eco-friendly process has been developed to convert methane, the major component of natural gas, to acetylene and hydrogen using a high frequency pulsed plasma. Acetylene is an important raw material in industry that is manufactured mainly by the reaction of calcium carbide with water. Acetylene is also manufactured by thermal cracking of hydrocarbons, or by partial oxidation of methane. These conventional processes require severe reaction conditions (a very high reaction temperature) and emit large amounts of greenhouse gas. The new process can convert methane to acetylene and hydrogen with a conversion efficiency of 52.8%, an acetylene selectivity of 91.8%, and a hydrogen ratio of 4.15 moles per mole acetylene at room temperature and atmospheric pressure. No environmental pollutant is emitted. 14 refs., 1 fig., 3 tabs.

  7. Natural diatomite process for removal of radioactivity from liquid waste.

    Science.gov (United States)

    Osmanlioglu, Ahmet Erdal

    2007-01-01

    Diatomite has a number of unique physical properties and has found diversified industrial utilization. The filtration characteristics are particularly significant in the purification of liquids. The purpose of this study was to test natural diatomaceous earth (diatomite) as an alternative material that could be used for removal of radioactivity from liquid waste. A pilot-scale column-type device was designed. Natural diatomite samples were ground, sieved and prepared to use as sorption media. In this study, real waste liquid was used as radioactive liquid having special conditions. The liquid waste contained three radionuclides (Cs-137, Cs-134 and Co-60). Following the treatment by diatomite, the radioactivity of liquid waste was reduced from the initial 2.60 Bq/ml to less than 0.40 Bq/ml. The results of this study show that most of the radioactivity was removed from the solution by processing with diatomite.

  8. Numerical Modeling of Natural and Enhanced Denitrification Processes in Aquifers

    Science.gov (United States)

    Kinzelbach, Wolfgang; SchäFer, Wolfgang; Herzer, JöRg

    1991-06-01

    Nitrate modeling in the groundwater environment must incorporate microbial denitrification as the major process of nitrate elimination. A multispecies transport model is presented which describes the interaction of oxygen, nitrate, organic carbon, and bacteria. Three phases (mobile pore water, biophase, and aquifer material) are taken into account. The model is applied to a natural aquifer situation as well as to an in situ remediation case where nitrate is employed as an oxidant. In the natural aquifer it is shown that the release of organic carbon from the matrix is the controlling factor for denitrification. In the remediation case, on the other hand, the data suggest that diffusion limitation of the nutrient supply to the biophase controls bacterial growth.

  9. Uranium stripping from tributyl phosphate by urea solutions

    Science.gov (United States)

    Skripchenko, S. Yu.; Titova, S. M.; Smirnov, A. L.; Rychkov, V. N.

    2016-09-01

    The process of uranium stripping from tri-n-butyl phosphate in kerosene by urea solutions was investigated at the volume ratio of the organic and aqueous phases of (1-10) : 1 in the temperature range of 20-60 °C. The stripping of uranium from a loaded organic phase increased with increasing urea content in the solution and with increasing temperature. Maximum recovery of uranium from tributyl phosphate was obtained using a solution that contained 8-12 mol/l of urea. The application of a urea solution for uranium stripping resulted in the strip product solution containing 200-240 g/L of uranium. The process of uranium stripping by dilute nitric acid was also investigated. Results of uranium stripping by the two methods are compared and discussed.

  10. Uranium (III) precipitation in molten chloride by wet argon sparging

    Science.gov (United States)

    Vigier, Jean-François; Laplace, Annabelle; Renard, Catherine; Miguirditchian, Manuel; Abraham, Francis

    2016-06-01

    In the context of pyrochemical processes for nuclear fuel treatment, the precipitation of uranium (III) in molten salt LiCl-CaCl2 (30-70 mol%) at 705 °C is studied. First, this molten chloride is characterized with the determination of the water dissociation constant. With a value of 10-4.0, the salt has oxoacid properties. Then, the uranium (III) precipitation using wet argon sparging is studied. The salt is prepared using UCl3 precursor. At the end of the precipitation, the salt is totally free of solubilized uranium. The main part is converted into UO2 powder but some uranium is lost during the process due to the volatility of uranium chloride. The main impurity of the resulting powder is calcium. The consequences of oxidative and reductive conditions on precipitation are studied. Finally, coprecipitation of uranium (III) and neodymium (III) is studied, showing a higher sensitivity of uranium (III) than neodymium (III) to precipitation.

  11. HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING

    Energy Technology Data Exchange (ETDEWEB)

    Girish Srinivas; Steven C. Gebhard; David W. DeBerry

    2002-04-01

    This first quarter report of 2002 describes progress on a project funded by the U.S. Department of Energy (DOE) to test a hybrid sulfur recovery process for natural gas upgrading. The process concept represents a low cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both on-shore and offshore applications. CrystaSulf{sup SM} (service mark of CrystaTech, Inc.) is a new nonaqueous sulfur recovery process that removes hydrogen sulfide (H{sub 2}S) from gas streams and converts it into elemental sulfur. CrystaSulf features high sulfur recovery similar to aqueous-iron liquid redox sulfur recovery processes, but differs from the aqueous processes in that CrystaSulf controls the location where elemental sulfur particles are formed. In the hybrid process, approximately 1/3 of the total H{sub 2}S in the natural gas is first oxidized to SO{sub 2} at low temperatures over a heterogeneous catalyst. Low temperature oxidation is done so that the H{sub 2}S can be oxidized in the presence of methane and other hydrocarbons without oxidation of the hydrocarbons. The project involves the development of a catalyst using laboratory/bench-scale catalyst testing, and then demonstration of the catalyst at CrystaTech's pilot plant in west Texas. In a previous reporting period tests were done to determine the effect of hydrocarbons such as n-hexane on catalyst performance with and without H{sub 2}S present. The experiments showed that hexane oxidation is suppressed when H{sub 2}S is present. Hexane represents the most reactive of the C1 to C6 series of alkanes. Since hexane exhibits low reactivity under H{sub 2}S oxidation conditions, and more importantly, does not

  12. HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING

    Energy Technology Data Exchange (ETDEWEB)

    Girish Srinivas; Steven C. Gebhard; David W. DeBerry

    2002-07-01

    This second quarter report of 2002 describes progress on a project funded by the U.S. Department of Energy (DOE) to test a hybrid sulfur recovery process for natural gas upgrading. The process concept represents a low cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both on-shore and offshore applications. CrystaSulf (service mark of CrystaTech, Inc.) is a new nonaqueous sulfur recovery process that removes hydrogen sulfide (H{sub 2}S) from gas streams and converts it into elemental sulfur. CrystaSulf features high sulfur recovery similar to aqueous-iron liquid redox sulfur recovery processes, but differs from the aqueous processes in that CrystaSulf controls the location where elemental sulfur particles are formed. In the hybrid process, approximately 1/3 of the total H{sub 2}S in the natural gas is first oxidized to SO{sub 2} at low temperatures over a heterogeneous catalyst. Low temperature oxidation is done so that the H{sub 2}S can be oxidized in the presence of methane and other hydrocarbons without oxidation of the hydrocarbons. The project involves the development of a catalyst using laboratory/bench-scale catalyst testing, and then demonstration of the catalyst at CrystaTech's pilot plant in west Texas. Previous reports described development of a catalyst with the required selectivity and efficiency for producing sulfur dioxide from H{sub 2}S. In the laboratory, the catalyst was shown to be robust and stable in the presence of several intentionally added contaminants, including condensate from the pilot plant site. This report describes testing using the laboratory apparatus but operated at the pilot plant using the actual pilot

  13. Release of uranium from candidate wasteforms

    OpenAIRE

    Collier, N.; Harrison, M.; Brogden, M,; Hanson, B

    2012-01-01

    Large volumes of depleted natural and low-enriched uranium exist in the UK waste inventory. This work reports on initial investigations of the leaching performance of candidate glass and cement encapsulation matrices containing UO3 powder as well as that of uranium oxide powders. The surface areas of UO3 powder and the monolith samples of UO3 conditioned in the glass and cement matrices were very different making leaching comparisons difficult. The results showed that for both types of monoli...

  14. URANIUM DECONTAMINATION WITH RESPECT TO ZIRCONIUM

    Science.gov (United States)

    Vogler, S.; Beederman, M.

    1961-05-01

    A process is given for separating uranium values from a nitric acid aqueous solution containing uranyl values, zirconium values and tetravalent plutonium values. The process comprises contacting said solution with a substantially water-immiscible liquid organic solvent containing alkyl phosphate, separating an organic extract phase containing the uranium, zirconium, and tetravalent plutonium values from an aqueous raffinate, contacting said organic extract phase with an aqueous solution 2M to 7M in nitric acid and also containing an oxalate ion-containing substance, and separating a uranium- containing organic raffinate from aqueous zirconium- and plutonium-containing extract phase.

  15. Uranium Mining and Norm in North America-Some Perspectives on Occupational Radiation Exposure.

    Science.gov (United States)

    Brown, Steven H; Chambers, Douglas B

    2017-07-01

    All soils and rocks contain naturally occurring radioactive materials (NORM). Many ores and raw materials contain relatively elevated levels of natural radionuclides, and processing such materials can further increase the concentrations of naturally occurring radionuclides. In the U.S., these materials are sometimes referred to as technologically-enhanced naturally occurring radioactive materials (TENORM). Examples of NORM minerals include uranium ores, monazite (a source of rare earth minerals), and phosphate rock used to produce phosphate fertilizer. The processing of these materials has the potential to result in above-background radiation exposure to workers. Following a brief review of the sources and potential for worker exposure from NORM in these varied industries, this paper will then present an overview of uranium mining and recovery in North America, including discussion on the mining methods currently being used for both conventional (underground, open pit) and in situ leach (ISL), also referred to as In Situ Recovery (ISR), and the production of NORM materials and wastes associated with these uranium recovery methods. The radiological composition of the NORM products and wastes produced and recent data on radiological exposures received by workers in the North American uranium recovery industry are then described. The paper also identifies the responsible government agencies in the U.S. and Canada assigned the authority to regulate and control occupational exposure from these NORM materials.

  16. Encapsulation of natural ingredient for skin protection via nanoemulsion process

    Science.gov (United States)

    Asmatulu, Eylem; Usta, Aybala; Alzahrani, Naif; Patil, Vinay; Vanderwall, Adeesha

    2017-04-01

    Many of the sunscreens are used during the hot summer time to protect the skin surface. However, some of ingredients in the sunscreens, such as oxybenzone, retinyl palmitate and synthetic fragrances including parabens, phthalates and synthetic musk may disrupt the cells on the skin and create harmful effects to human body. Natural oils may be considered for substitution of harmful ingredients in sunscreens. Many natural oils (e.g., macadamia oil, sesame oil, almond oil and olive oil) have UV protective property and on top of that they have natural essences. Among the natural oils, olive oil has a long history of being used as a home remedy for skincare. Olive oil is used or substituted for cleanser, moisturizer, antibacterial agent and massage reliever for muscle fatigue. It is known that sun protection factor (SPF) of olive oil is around eight. There has been relatively little scientific work performed on the effect of olive oil on the skin as sunscreen. With nanoencapsulation technique, UV light protection of the olive oil can be extended which will provide better coverage for the skin throughout the day. In the present study, natural olive oil was incorporated with DI water and surfactant (sodium dodecyl sulfate - SDS) and sonicated using probe sonicators. Sonication time, and concentrations of olive oil, DI water and surfactant were investigated in detail. The produced nanoemulsions were characterized using dynamic light scattering, and UV-Vis spectroscopy. It is believed that the nanoencupsulation of olive oil could provide better skin protection by slow releasing and deeper penetration of the nanoemulsion on skin surface. Undergraduate engineering students were involved in the project and observed all the process during the laboratory studies, as well as data collection, analysis and presentation. This experience based learning will likely enhance the students' skills and interest in the scientific and engineering studies.

  17. Mobilization of radionuclides from uranium mill tailings and related waste materials in anaerobic environments

    Science.gov (United States)

    Landa, E.R.

    2003-01-01

    Specific extraction studies in our laboratory have shown that iron and manganese oxide- and alkaline earth sulfate minerals are important hosts of radium in uranium mill tailings. Iron- and sulfate-reducing bacteria may enhance the release of radium (and its analog barium) from uranium mill tailings, oil field pipe scale [a major technologically enhanced naturally occurring radioactive material (TENORM) waste], and jarosite (a common mineral in sulfuric acid processed-tailings). These research findings are reviewed and discussed in the context of nuclear waste forms (such as barium sulfate matrices), radioactive waste management practices, and geochemical environments in the Earth's surficial and shallow subsurface regions.

  18. Evaluation of the effectiveness of the filtration leaching for uranium recovery from uranium ore

    Directory of Open Access Journals (Sweden)

    Bolat Uralbekov

    2015-09-01

    Full Text Available The physical and chemical processes taking place in filtration leaching of uranium from uranium ore sample by sulphuric acid solution have been studied by modern physico-chemical methods (X-ray diffraction, scanning electron spectroscopy, electron probe microanalysis, optical emission spectroscope, ICP OES. Column leaching test was carried out for ore samples obtained from a uranium in-situ leaching (ISL mining site using deluted sulphuricacid to study the evolution of various elements concentration in the pregnant leach solution. It has been shown that the uranium in pregnant solutions appears by dissolution of calcium and magnesium carbonates and uranium minerals as well. It was found the decreasing of filtration coefficient from 0.099 m day-1 to 0.082 m day-1, due to the presence of mechanical and chemical mudding. Partial extraction of uranium (85% from the ore has been explained by the slow diffusion of sulfuric acid to the uranium minerals locates in the cracks of silicate minerals. It was concluded that the studied uranium ore sample according to adverse geotechnical parameters is not suitable for uranium extraction by filtration leaching.

  19. Recent Technological Advances in Natural Language Processing and Artificial Intelligence

    OpenAIRE

    Shah, Nishal Pradeepkumar

    2012-01-01

    A recent advance in computer technology has permitted scientists to implement and test algorithms that were known from quite some time (or not) but which were computationally expensive. Two such projects are IBM's Jeopardy as a part of its DeepQA project [1] and Wolfram's Wolframalpha[2]. Both these methods implement natural language processing (another goal of AI scientists) and try to answer questions as asked by the user. Though the goal of the two projects is similar, both of them have a ...

  20. Natural Language Processing as a Discipline at LLNL

    Energy Technology Data Exchange (ETDEWEB)

    Firpo, M A

    2005-02-04

    The field of Natural Language Processing (NLP) is described as it applies to the needs of LLNL in handling free-text. The state of the practice is outlined with the emphasis placed on two specific aspects of NLP: Information Extraction and Discourse Integration. A brief description is included of the NLP applications currently being used at LLNL. A gap analysis provides a look at where the technology needs work in order to meet the needs of LLNL. Finally, recommendations are made to meet these needs.

  1. Removal of Uranium (Ⅵ) by Fixed Bed Ion-exchange Column Using Natural Zeolite Coated with Manganese Oxide%锰氧化物负载沸石固定床离子交换柱去除铀(VI)的研究

    Institute of Scientific and Technical Information of China (English)

    邹卫华; 赵蕾; 韩润平

    2009-01-01

    The adsorption of uranium (Ⅵ) on the manganese oxide coated zeolite (MOCZ) from aqueous solution was investigated in a fixed-bed column. The experiments were conducted to investigate the effects of bed height, flow rate, particle size, initial concentration of uranium (Ⅵ), initial pH, presence of salt and competitive ions. The U-uptake by MOCZ increased with initial uranium (Ⅵ) concentration and bed height, but decreased as the flow rate and particle size increased. In the presence of salt and competitive ions, the breakthrough time was shorter. The ad-sorption capacity reached a maximum at pH of 6.3. The Thomas model was applied to the experimental data to de-termine the characteristic parameters of the column for process design using linear regression. The breakthrough curves calculated from the model were in good agreement with the experimental data. The BDST model was used to study the influence of bed height on the adsorption of uranium (Ⅵ). Desorption of uranium (Ⅵ) in the MOCZ column was investigated. The column could be used for at least four adsorption-desorption cycles using 0.1 mol'L-1 NaHCO3 solution as the elution. After desorption and regeneration with deionized water, MOCZ could be reused to adsorb uranium (Ⅵ) at a comparable capacity. Compared to raw zeolite, MOCZ showed better capacity for uranium (Ⅵ) removal.

  2. Nuclear toxicology file: ecological consequences of a chronic exposure to uranium; Dossier toxicologie nucleaire: Consequences ecologiques d'une exposition chronique a l'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Adam, Ch.; Alonzo, F.; Bonzom, J.M.; Gilbin, R.; Garnier-Laplace, J.; Simon, O. [Institut de Radioprotection et de Surete Nucleaire (IRSN:DEI/SECRE), Service d' Etude du Comportement des Radionucleides dans les Ecosystemes, 13 - Saint-Paul-lez-Durance (France)

    2008-09-15

    This article presents the thought process and the current developments, based on the experimental acquisition of the answers of the alive organisms to the chronic low dose exposures of natural uranium in fresh water, to identify the consequences of this exposure on the populations composing the ecosystems. The results acquired on the zebra fish (Danio rerio) show an impact on the first steps of development. We note a delay of hatching upon 40 % from 20 {mu}g/l of uranium. This delay comes along with a decrease of the size and with a reduction of the growth of larvas as well as with an increase of their mortality for higher uranium concentration. For adults exposed to uranium a decrease of reproduction success is observed from a concentration of 20{mu}g/l. The consequences in term of fertility (total number of laid roes) are drastic, with a reduction of a factor 2 and 60, for the organisms exposed respectively to 20 and 250 {mu}g/l of uranium. A study was also made on several generations (populations of benthic invertebrates), it suggests an adaptation (genetic selection) but created a bigger fragility to a new environment even identical to their environment of origin with notably a decrease of the reproduction. (N.C.)

  3. Natural Language Processing methods and systems for biomedical ontology learning.

    Science.gov (United States)

    Liu, Kaihong; Hogan, William R; Crowley, Rebecca S

    2011-02-01

    While the biomedical informatics community widely acknowledges the utility of domain ontologies, there remain many barriers to their effective use. One important requirement of domain ontologies is that they must achieve a high degree of coverage of the domain concepts and concept relationships. However, the development of these ontologies is typically a manual, time-consuming, and often error-prone process. Limited resources result in missing concepts and relationships as well as difficulty in updating the ontology as knowledge changes. Methodologies developed in the fields of Natural Language Processing, information extraction, information retrieval and machine learning provide techniques for automating the enrichment of an ontology from free-text documents. In this article, we review existing methodologies and developed systems, and discuss how existing methods can benefit the development of biomedical ontologies. Published by Elsevier Inc.

  4. Natural radionuclide concentrations in processed materials from Thai mineral industries.

    Science.gov (United States)

    Chanyotha, S; Kranrod, C; Chankow, N; Kritsananuwat, R; Sriploy, P; Pangza, K

    2012-11-01

    The naturally occurring radioactive materials (NORMs) distributed in products, by-products and waste produced from Thai mineral industries were investigated. Samples were analysed for radioactivity concentrations of two principal NORM isotopes: (226)Ra and (228)Ra. The enrichment of NORM was found to occur during the treatment process of some minerals. The highest activity of (226)Ra (7 × 10(7) Bq kg(-1)) was in the scale from tantalum processing. The radium concentration in the discarded by-product material from metal ore dressing was also enriched by 3-10 times. Phosphogypsum, a waste produced from the production of phosphate fertilisers, contained 700 times the level of (226)Ra concentration found in phosphate ore. Hence, these residues were also sources of exposure to workers and the public, which needed to be controlled.

  5. Rethinking the process of detrainment: jets in obstructed natural flows

    Science.gov (United States)

    Mossa, Michele; de Serio, Francesca

    2016-12-01

    A thorough understanding of the mixing and diffusion of turbulent jets released in porous obstructions is still lacking in literature. This issue is undoubtedly of interest because it is not strictly limited to vegetated flows, but also includes outflows which come from different sources and which spread among oyster or wind farms, as well as aerial pesticide treatments sprayed onto orchards. The aim of the present research is to analyze this process from a theoretical point of view. Specifically, by examining the entrainment coefficient, it is deduced that the presence of a canopy prevents a momentum jet from having an entrainment process, but rather promotes its detrainment. In nature, detrainment is usually associated with buoyancy-driven flows, such as plumes or density currents flowing in a stratified environment. The present study proves that detrainment occurs also when a momentum-driven jet is issued in a not-stratified obstructed current, such as a vegetated flow.

  6. Detection of Blood Culture Bacterial Contamination using Natural Language Processing

    Science.gov (United States)

    Matheny, Michael E.; FitzHenry, Fern; Speroff, Theodore; Hathaway, Jacob; Murff, Harvey J.; Brown, Steven H.; Fielstein, Elliot M.; Dittus, Robert S.; Elkin, Peter L.

    2009-01-01

    Microbiology results are reported in semi-structured formats and have a high content of useful patient information. We developed and validated a hybrid regular expression and natural language processing solution for processing blood culture microbiology reports. Multi-center Veterans Affairs training and testing data sets were randomly extracted and manually reviewed to determine the culture and sensitivity as well as contamination results. The tool was iteratively developed for both outcomes using a training dataset, and then evaluated on the test dataset to determine antibiotic susceptibility data extraction and contamination detection performance. Our algorithm had a sensitivity of 84.8% and a positive predictive value of 96.0% for mapping the antibiotics and bacteria with appropriate sensitivity findings in the test data. The bacterial contamination detection algorithm had a sensitivity of 83.3% and a positive predictive value of 81.8%. PMID:20351890

  7. Detection of blood culture bacterial contamination using natural language processing.

    Science.gov (United States)

    Matheny, Michael E; Fitzhenry, Fern; Speroff, Theodore; Hathaway, Jacob; Murff, Harvey J; Brown, Steven H; Fielstein, Elliot M; Dittus, Robert S; Elkin, Peter L

    2009-11-14

    Microbiology results are reported in semi-structured formats and have a high content of useful patient information. We developed and validated a hybrid regular expression and natural language processing solution for processing blood culture microbiology reports. Multi-center Veterans Affairs training and testing data sets were randomly extracted and manually reviewed to determine the culture and sensitivity as well as contamination results. The tool was iteratively developed for both outcomes using a training dataset, and then evaluated on the test dataset to determine antibiotic susceptibility data extraction and contamination detection performance. Our algorithm had a sensitivity of 84.8% and a positive predictive value of 96.0% for mapping the antibiotics and bacteria with appropriate sensitivity findings in the test data. The bacterial contamination detection algorithm had a sensitivity of 83.3% and a positive predictive value of 81.8%.

  8. Semantic biomedical resource discovery: a Natural Language Processing framework.

    Science.gov (United States)

    Sfakianaki, Pepi; Koumakis, Lefteris; Sfakianakis, Stelios; Iatraki, Galatia; Zacharioudakis, Giorgos; Graf, Norbert; Marias, Kostas; Tsiknakis, Manolis

    2015-09-30

    A plethora of publicly available biomedical resources do currently exist and are constantly increasing at a fast rate. In parallel, specialized repositories are been developed, indexing numerous clinical and biomedical tools. The main drawback of such repositories is the difficulty in locating appropriate resources for a clinical or biomedical decision task, especially for non-Information Technology expert users. In parallel, although NLP research in the clinical domain has been active since the 1960s, progress in the development of NLP applications has been slow and lags behind progress in the general NLP domain. The aim of the present study is to investigate the use of semantics for biomedical resources annotation with domain specific ontologies and exploit Natural Language Processing methods in empowering the non-Information Technology expert users to efficiently search for biomedical resources using natural language. A Natural Language Processing engine which can "translate" free text into targeted queries, automatically transforming a clinical research question into a request description that contains only terms of ontologies, has been implemented. The implementation is based on information extraction techniques for text in natural language, guided by integrated ontologies. Furthermore, knowledge from robust text mining methods has been incorporated to map descriptions into suitable domain ontologies in order to ensure that the biomedical resources descriptions are domain oriented and enhance the accuracy of services discovery. The framework is freely available as a web application at ( http://calchas.ics.forth.gr/ ). For our experiments, a range of clinical questions were established based on descriptions of clinical trials from the ClinicalTrials.gov registry as well as recommendations from clinicians. Domain experts manually identified the available tools in a tools repository which are suitable for addressing the clinical questions at hand, either

  9. Uranium and free trade

    Energy Technology Data Exchange (ETDEWEB)

    1988-08-01

    This report was prepared by a working group of the Committee on International Trade in Uranium of the Uranium Institute. The report describes the general benefits of free trade and their relevance in the uranium market, and compares government restrictions on Western world uranium trade with those in other commodity markets. It is not directly concerned with restrictions designed to discourage nuclear weapons proliferation. The Uranium Institute and its members fully support the objective of nuclear non-proliferation. The report takes as given the current non-proliferation regime and focuses on economic and commercial restrictions imposed by governments on international trade in uranium, recognising that governments will always have a special interest in uranium trade owing to its potential weapons use. (author).

  10. Evolution of uranium and thorium minerals

    Science.gov (United States)

    Hazen, R. M.; Ewing, R. C.; Sverjensky, D. A.

    2009-12-01

    The origins and near-surface distributions of the approximately 250 known uranium and/or thorium minerals elucidate principles of mineral evolution. This history can be divided into four phases. The first, from ~4.5 to 3.5 Ga, involved successive concentrations of uranium and thorium from their initial uniform trace distribution into magmatic-related fluids from which the first U4+ and Th4+ minerals, uraninite (UO2), thorianite (ThO2) and coffinite (USiO4), precipitated in the crust. The second period, from ~3.5 to 2.2 Ga, saw the formation of large low-grade concentrations of detrital uraninite (containing several weight percent Th) in the Witwatersrand-type quartz-pebble conglomerates deposited in a highly anoxic fluvial environment. Abiotic alteration of uraninite and coffinite, including radiolysis and auto-oxidation caused by radioactive decay and the formation of helium from alpha particles, may have resulted in the formation of a limited suite of uranyl oxide-hydroxides. Earth’s third phase of uranium mineral evolution, during which most known U minerals first precipitated from reactions of soluble uranyl (U6+O2)2+ complexes, followed the Great Oxidation Event (GOE) at ~2.2 Ga and thus was mediated indirectly by biologic activity. Most uraninite deposited during this phase was low in Th and precipitated from saline and oxidizing hydrothermal solutions (100 to 300°C) transporting (UO2)2+-chloride complexes. Examples include the unconformity- and vein-type U deposits (Australia and Canada) and the unique Oklo natural nuclear reactors in Gabon. The onset of hydrothermal transport of (UO2)2+ complexes in the upper crust may reflect the availability of CaSO4-bearing evaporites after the GOE. During this phase, most uranyl minerals would have been able to form in the O2-bearing near-surface environment for the first time through weathering processes. The fourth phase of uranium mineralization began approximately 400 million years ago, as the rise of land plants

  11. Remedial action plan for the inactive uranium processing site at Naturita, Colorado. Remedial action selection report: Attachment 2, geology report; Attachment 3, ground water hydrology report; Attachment 4, supplemental information

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    The uranium processing site near Naturita, Colorado, is one of 24 inactive uranium mill sites designated to be cleaned up by the U.S. 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 U.S. 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 U.S. Environmental Protection Agency (EPA). This RAP 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 RAP, upon concurrence and execution by the DOE, the state of Colorado, and the NRC, becomes Appendix B of the cooperative agreement between the DOE and the state of Colorado.

  12. Solid phase extraction of uranium(VI) onto benzoylthiourea-anchored activated carbon.

    Science.gov (United States)

    Zhao, Yongsheng; Liu, Chunxia; Feng, Miao; Chen, Zhen; Li, Shuqiong; Tian, Gan; Wang, Li; Huang, Jingbo; Li, Shoujian

    2010-04-15

    A new solid phase extractant selective for uranium(VI) based on benzoylthiourea anchored to activated carbon was developed via hydroxylation, amidation and reaction with benzoyl isothiocyanate in sequence. Fourier transform infrared spectroscopy and total element analysis proved that benzoylthiourea had been successfully grafted to the surface of the activated carbon, with a loading capacity of 1.2 mmol benzoylthiourea per gram of activated carbon. The parameters that affect the uranium(VI) sorption, such as contact time, solution pH, initial uranium(VI) concentration, adsorbent dose and temperature, have been investigated. Results have been analyzed by Langmuir and Freundlich isotherm; the former was more suitable to describe the sorption process. The maximum sorption capacity (82 mg/g) for uranium(VI) was obtained at experimental conditions. The rate constant for the uranium sorption by the as-synthesized extractant was 0.441 min(-1) from the first order rate equation. Thermodynamic parameters (DeltaH(0)=-46.2 kJ/mol; DeltaS(0)=-98.0 J/mol K; DeltaG(0)=-17.5 kJ/mol) showed the adsorption of an exothermic process and spontaneous nature, respectively. Additional studies indicated that the benzoylthiourea-anchored activated carbon (BT-AC) selectively sorbed uranyl ions in the presence of competing ions, Na(+), Co(2+), Sr(2+), Cs(+) and La(3+).

  13. Influence of different natural physical fields on biological processes

    Science.gov (United States)

    Mashinsky, A. L.

    2001-01-01

    In space flight conditions gravity, magnetic, and electrical fields as well as ionizing radiation change both in size, and in direction. This causes disruptions in the conduct of some physical processes, chemical reactions, and metabolism in living organisms. In these conditions organisms of different phylogenetic level change their metabolic reactions undergo changes such as disturbances in ionic exchange both in lower and in higher plants, changes in cell morphology for example, gyrosity in Proteus ( Proteus vulgaris), spatial disorientation in coleoptiles of Wheat ( Triticum aestivum) and Pea ( Pisum sativum) seedlings, mutational changes in Crepis ( Crepis capillaris) and Arabidopsis ( Arabidopsis thaliana) seedling. It has been found that even in the absence of gravity, gravireceptors determining spatial orientation in higher plants under terrestrial conditions are formed in the course of ontogenesis. Under weightlessness this system does not function and spatial orientation is determined by the light flux gradient or by the action of some other factors. Peculiarities of the formation of the gravireceptor apparatus in higher plants, amphibians, fish, and birds under space flight conditions have been observed. It has been found that the system in which responses were accompanied by phase transition have proven to be gravity-sensitive under microgravity conditions. Such reactions include also the process of photosynthesis which is the main energy production process in plants. In view of the established effects of microgravity and different natural physical fields on biological processes, it has been shown that these processes change due to the absence of initially rigid determination. The established biological effect of physical fields influence on biological processes in organisms is the starting point for elucidating the role of gravity and evolutionary development of various organisms on Earth.

  14. Fate of Uranium During Transport Across the Groundwater-Surface Water Interface

    Energy Technology Data Exchange (ETDEWEB)

    Jaffe, Peter R. [Princeton Univ., NJ (United States); Kaplan, Daniel I. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-06-30

    Discharge of contaminated groundwater to surface waters is of concern at many DOE facilities. For example, at F-Area and TNX-Area on the Savannah River Site, contaminated groundwater, including uranium, is already discharging into natural wetlands. It is at this interface where contaminants come into contact with the biosphere. These this research addressed a critical knowledge gap focusing on the geochemistry of uranium (or for that matter, any redox-active contaminant) in wetland systems. Understanding the interactions between hydrological, microbial, and chemical processes will make it possible to provide a more accurate conceptual and quantitative understanding of radionuclide fate and transport under these unique conditions. Understanding these processes will permit better long-term management and the necessary technical justification for invoking Monitored Natural Attenuation of contaminated wetland areas. Specifically, this research did provide new insights on how plant-induced alterations to the sediment biogeochemical processes affect the key uranium reducing microorganisms, the uranium reduction, its spatial distribution, the speciation of the immobilized uranium, and its long-term stability. This was achieved by conducting laboratory mesocosm wetland experiments as well as field measurements at the SRNL. Results have shown that uranium can be immobilized in wetland systems. To a degree some of the soluble U(VI) was reduced to insoluble U(IV), but the majority of the immobilized U was incorporated into iron oxyhydroxides that precipitated onto the root surfaces of wetland plants. This U was immobilized mostly as U(VI). Because it was immobilized in its oxidized form, results showed that dry spells, resulting in the lowering of the water table and the exposure of the U to oxic conditions, did not result in U remobilization.

  15. Uranium isotopes fingerprint biotic reduction

    Science.gov (United States)

    Stylo, Malgorzata; Neubert, Nadja; Wang, Yuheng; Monga, Nikhil; Romaniello, Stephen J.; Weyer, Stefan; Bernier-Latmani, Rizlan

    2015-01-01

    Knowledge of paleo-redox conditions in the Earth’s history provides a window into events that shaped the evolution of life on our planet. The role of microbial activity in paleo-redox processes remains unexplored due to the inability to discriminate biotic from abiotic redox transformations in the rock record. The ability to deconvolute these two processes would provide a means to identify environmental niches in which microbial activity was prevalent at a specific time in paleo-history and to correlate specific biogeochemical events with the corresponding microbial metabolism. Here, we demonstrate that the isotopic signature associated with microbial reduction of hexavalent uranium (U), i.e., the accumulation of the heavy isotope in the U(IV) phase, is readily distinguishable from that generated by abiotic uranium reduction in laboratory experiments. Thus, isotope signatures preserved in the geologic record through the reductive precipitation of uranium may provide the sought-after tool to probe for biotic processes. Because uranium is a common element in the Earth’s crust and a wide variety of metabolic groups of microorganisms catalyze the biological reduction of U(VI), this tool is applicable to a multiplicity of geological epochs and terrestrial environments. The findings of this study indicate that biological activity contributed to the formation of many authigenic U deposits, including sandstone U deposits of various ages, as well as modern, Cretaceous, and Archean black shales. Additionally, engineered bioremediation activities also exhibit a biotic signature, suggesting that, although multiple pathways may be involved in the reduction, direct enzymatic reduction contributes substantially to the immobilization of uranium. PMID:25902522

  16. Biosorption of uranium by human black hair.

    Science.gov (United States)

    Saini, Amardeep Singh; Melo, Jose Savio

    2015-04-01

    Naturally available low cost materials have gained importance as effective alternative to conventional sorbents for the removal of metal ions from water. The present study describes the use of black hair waste as a sorbent for the removal of uranium ions from an aqueous medium. Alkali treatment of the biomass resulted in a significant increase in its uptake capacity. The optimum pH and contact time for uranium removal were 4.5 and 2 h respectively. It was observed that the experimental data fits well in Ho's pseudo-second order kinetic model. Binding of uranium to the biomass was confirmed using FT-IR spectroscopy. Thus, the present study could demonstrate the utility of human black hair to remove uranium from aqueous medium.

  17. Independent component processes underlying emotions during natural music listening.

    Science.gov (United States)

    Rogenmoser, Lars; Zollinger, Nina; Elmer, Stefan; Jäncke, Lutz

    2016-09-01

    The aim of this study was to investigate the brain processes underlying emotions during natural music listening. To address this, we recorded high-density electroencephalography (EEG) from 22 subjects while presenting a set of individually matched whole musical excerpts varying in valence and arousal. Independent component analysis was applied to decompose the EEG data into functionally distinct brain processes. A k-means cluster analysis calculated on the basis of a combination of spatial (scalp topography and dipole location mapped onto the Montreal Neurological Institute brain template) and functional (spectra) characteristics revealed 10 clusters referring to brain areas typically involved in music and emotion processing, namely in the proximity of thalamic-limbic and orbitofrontal regions as well as at frontal, fronto-parietal, parietal, parieto-occipital, temporo-occipital and occipital areas. This analysis revealed that arousal was associated with a suppression of power in the alpha frequency range. On the other hand, valence was associated with an increase in theta frequency power in response to excerpts inducing happiness compared to sadness. These findings are partly compatible with the model proposed by Heller, arguing that the frontal lobe is involved in modulating valenced experiences (the left frontal hemisphere for positive emotions) whereas the right parieto-temporal region contributes to the emotional arousal.

  18. HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING

    Energy Technology Data Exchange (ETDEWEB)

    Dennis Dalrymple

    2004-06-01

    This final report describes the objectives, technical approach, results and conclusions for a project funded by the U.S. Department of Energy to test a hybrid sulfur recovery process for natural gas upgrading. The process concept is a configuration of CrystaTech, Inc.'s CrystaSulf{reg_sign} process which utilizes a direct oxidation catalyst upstream of the absorber tower to oxidize a portion of the inlet hydrogen sulfide (H{sub 2}S) to sulfur dioxide (SO{sub 2}) and elemental sulfur. This hybrid configuration of CrystaSulf has been named CrystaSulf-DO and represents a low-cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day and more. This hybrid process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both onshore and offshore applications. CrystaSulf is a nonaqueous sulfur recovery process that removes H{sub 2}S from gas streams and converts it to elemental sulfur. In CrystaSulf, H{sub 2}S in the inlet gas is reacted with SO{sub 2} to make elemental sulfur according to the liquid phase Claus reaction: 2H{sub 2}S + SO{sub 2} {yields} 2H{sub 2}O + 3S. The SO{sub 2} for the reaction can be supplied from external sources by purchasing liquid SO{sub 2} and injecting it into the CrystaSulf solution, or produced internally by converting a portion of the inlet gas H{sub 2}S to SO{sub 2} or by burning a portion of the sulfur produced to make SO{sub 2}. CrystaSulf features high sulfur recovery similar to aqueous-iron liquid redox sulfur recovery processes, but differs from the aqueous processes in that CrystaSulf controls the location where elemental sulfur particles are formed. In the hybrid process, the needed SO{sub 2} is produced by placing a bed of direct oxidation catalyst in the inlet gas stream to oxidize

  19. Uranium hexafluoride public risk

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, D.R.; Hui, T.E.; Yurconic, M.; Johnson, J.R.

    1994-08-01

    The limiting value for uranium toxicity in a human being should be based on the concentration of uranium (U) in the kidneys. The threshold for nephrotoxicity appears to lie very near 3 {mu}g U per gram kidney tissue. There does not appear to be strong scientific support for any other improved estimate, either higher or lower than this, of the threshold for uranium nephrotoxicity in a human being. The value 3 {mu}g U per gram kidney is the concentration that results from a single intake of about 30 mg soluble uranium by inhalation (assuming the metabolism of a standard person). The concentration of uranium continues to increase in the kidneys after long-term, continuous (or chronic) exposure. After chronic intakes of soluble uranium by workers at the rate of 10 mg U per week, the concentration of uranium in the kidneys approaches and may even exceed the nephrotoxic limit of 3 {mu}g U per gram kidney tissue. Precise values of the kidney concentration depend on the biokinetic model and model parameters assumed for such a calculation. Since it is possible for the concentration of uranium in the kidneys to exceed 3 {mu}g per gram tissue at an intake rate of 10 mg U per week over long periods of time, we believe that the kidneys are protected from injury when intakes of soluble uranium at the rate of 10 mg U per week do not continue for more than two consecutive weeks. For long-term, continuous occupational exposure to low-level, soluble uranium, we recommend a reduced weekly intake limit of 5 mg uranium to prevent nephrotoxicity in workers. Our analysis shows that the nephrotoxic limit of 3 {mu}g U per gram kidney tissues is not exceeded after long-term, continuous uranium intake at the intake rate of 5 mg soluble uranium per week.

  20. Licensing of the Process Uranium Plant Mineral, Retortillo-Santidad; Licenciamiento de la Planta de Proceso de Mineral de Uranio Retortillo-Sanidad

    Energy Technology Data Exchange (ETDEWEB)

    Blazquez Arroyo, E.; Colilla Peletero, J.; Bellon del Rosal, F.; Mancipe Jimenez, D. C.; Garrido Delgado, C.; Garcia-Bermejo Fernandez, R.

    2013-07-01

    Berkeley Minera Spain, S.A. provides for the operation of the concession Retortillo-Santidad (Salamanca) mining and construction of a beneficiation plant of uranium ore, for the production of uranium concentrate (Yellow cake). In Spain, the project Quercus, ENUSA, obtained the last prior authorization in 1979. Since then, there has been a continuous evolution in the aspects technical and regulatory. This paper is the documentation and content necessary for the licensing of a uranium production plant. In particular, to obtain the prior authorization as radioactive installation of 1st category (RINR).

  1. Bioremediation of uranium contamination with enzymatic uranium reduction

    Science.gov (United States)

    Lovley, D.R.; Phillips, E.J.P.

    1992-01-01

    Enzymatic uranium reduction by Desulfovibrio desulfuricans readily removed uranium from solution in a batch system or when D. desulfuricans was separated from the bulk of the uranium-containing water by a semipermeable membrane. Uranium reduction continued at concentrations as high as 24 mM. Of a variety of potentially inhibiting anions and metals evaluated, only high concentrations of copper inhibited uranium reduction. Freeze-dried cells, stored aerobically, reduced uranium as fast as fresh cells. D. desulfuricans reduced uranium in pH 4 and pH 7.4 mine drainage waters and in uraniumcontaining groundwaters from a contaminated Department of Energy site. Enzymatic uranium reduction has several potential advantages over other bioprocessing techniques for uranium removal, the most important of which are as follows: the ability to precipitate uranium that is in the form of a uranyl carbonate complex; high capacity for uranium removal per cell; the formation of a compact, relatively pure, uranium precipitate.

  2. Uranium hexafluoride bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Burnham, S.L.

    1988-01-01

    This bibliography is a compilation of reports written about the transportation, handling, safety, and processing of uranium hexafluoride. An on-line literature search was executed using the DOE Energy files and the Nuclear Science Abstracts file to identify pertinent reports. The DOE Energy files contain unclassified information that is processed at the Office of Scientific and Technical Information of the US Department of Energy. The reports selected from these files were published between 1974 and 1983. Nuclear Science Abstracts contains unclassified international nuclear science and technology literature published from 1948 to 1976. In addition, scientific and technical reports published by the US Atomic Energy Commission and the US Energy Research and Development Administration, as well as those published by other agencies, universities, and industrial and research organizations, are included in the Nuclear Science Abstracts file. An alphabetical listing of the acronyms used to denote the corporate sponsors follows the bibliography.

  3. Natural Language Processing Technologies in Radiology Research and Clinical Applications

    Science.gov (United States)

    Cai, Tianrun; Giannopoulos, Andreas A.; Yu, Sheng; Kelil, Tatiana; Ripley, Beth; Kumamaru, Kanako K.; Rybicki, Frank J.

    2016-01-01

    The migration of imaging reports to electronic medical record systems holds great potential in terms of advancing radiology research and practice by leveraging the large volume of data continuously being updated, integrated, and shared. However, there are significant challenges as well, largely due to the heterogeneity of how these data are formatted. Indeed, although there is movement toward structured reporting in radiology (ie, hierarchically itemized reporting with use of standardized terminology), the majority of radiology reports remain unstructured and use free-form language. To effectively “mine” these large datasets for hypothesis testing, a robust strategy for extracting the necessary information is needed. Manual extraction of information is a time-consuming and often unmanageable task. “Intelligent” search engines that instead rely on natural language processing (NLP), a computer-based approach to analyzing free-form text or speech, can be used to automate this data mining task. The overall goal of NLP is to translate natural human language into a structured format (ie, a fixed collection of elements), each with a standardized set of choices for its value, that is easily manipulated by computer programs to (among other things) order into subcategories or query for the presence or absence of a finding. The authors review the fundamentals of NLP and describe various techniques that constitute NLP in radiology, along with some key applications. ©RSNA, 2016 PMID:26761536

  4. Natural Language Processing in Radiology: A Systematic Review.

    Science.gov (United States)

    Pons, Ewoud; Braun, Loes M M; Hunink, M G Myriam; Kors, Jan A

    2016-05-01

    Radiological reporting has generated large quantities of digital content within the electronic health record, which is potentially a valuable source of information for improving clinical care and supporting research. Although radiology reports are stored for communication and documentation of diagnostic imaging, harnessing their potential requires efficient and automated information extraction: they exist mainly as free-text clinical narrative, from which it is a major challenge to obtain structured data. Natural language processing (NLP) provides techniques that aid the conversion of text into a structured representation, and thus enables computers to derive meaning from human (ie, natural language) input. Used on radiology reports, NLP techniques enable automatic identification and extraction of information. By exploring the various purposes for their use, this review examines how radiology benefits from NLP. A systematic literature search identified 67 relevant publications describing NLP methods that support practical applications in radiology. This review takes a close look at the individual studies in terms of tasks (ie, the extracted information), the NLP methodology and tools used, and their application purpose and performance results. Additionally, limitations, future challenges, and requirements for advancing NLP in radiology will be discussed. (©) RSNA, 2016 Online supplemental material is available for this article.

  5. Roget's Thesaurus as a Lexical Resource for Natural Language Processing

    CERN Document Server

    Jarmasz, Mario

    2012-01-01

    WordNet proved that it is possible to construct a large-scale electronic lexical database on the principles of lexical semantics. It has been accepted and used extensively by computational linguists ever since it was released. Inspired by WordNet's success, we propose as an alternative a similar resource, based on the 1987 Penguin edition of Roget's Thesaurus of English Words and Phrases. Peter Mark Roget published his first Thesaurus over 150 years ago. Countless writers, orators and students of the English language have used it. Computational linguists have employed Roget's for almost 50 years in Natural Language Processing, however hesitated in accepting Roget's Thesaurus because a proper machine tractable version was not available. This dissertation presents an implementation of a machine-tractable version of the 1987 Penguin edition of Roget's Thesaurus - the first implementation of its kind to use an entire current edition. It explains the steps necessary for taking a machine-readable file and transform...

  6. The polymer–polymorphoid nature of glass aging process

    Directory of Open Access Journals (Sweden)

    Victor S. Minaev

    2015-12-01

    Full Text Available Based on the concept of polymeric–polymorphous structure of glass and glass-forming liquid experimental data have been analyzed revealing the nature of glass aging. We show that the glass forming substance is a copolymer consisting of structural nano-fragments (polymorphoids in different polymorphous modifications (PM of the material having no translational symmetry (long-range order. The study revealed that the process and degree of glass aging influences the properties of glasses, including a change in enthalpy, manifested in the exothermic and endothermic effects observed in thermograms of differential scanning calorimetry of heated and cooled glasses. We have shown that the physicochemical essence of aging is the transformation of polymorphoids from high-temperature PM (HTPM to low-temperature PM (LTPM which results, under certain conditions, in LTPM crystallization.

  7. New treating processes for sulfur-containing natural gases

    Energy Technology Data Exchange (ETDEWEB)

    Kislenko, N.; Aphanasiev, A.; Nabokov, S.; Ismailova, H. [VNIIGAS, Moscow (Russian Federation)

    1996-12-31

    The traditional method of removing H{sub 2}S from sour natural gases is first to treat the gas with a solvent and then to recover the H{sub 2}S from the sour stream in a Claus plant. This method recovers up to 97% of the sulfur when a three-stage Claus unit is employed. Amine/Claus units have operating difficulties for small sulfur capacities (up to 5 tons/day) because the operation of the fired equipment (reaction furnace) is much more difficult. Therefore, for small scale sulfur recovery plants redox processes which exhibit a significant reduction in investment and operating costs are normally used. Many different factors influence the choice of gas desulfurization technology--composition and gas flow, environmental sulfur recovery requirements and CO{sub 2}/H{sub 2}S ratio.

  8. Geology of the Sievi, Kuru and Askola sites. Uranium mineralogy at Askola

    Energy Technology Data Exchange (ETDEWEB)

    Markovaara-Koivisto, M.; Read, D.; Lindberg, A.; Siitari-Kauppi, M.; Togneri, L.

    2009-07-01

    The natural geochemical retardation systems of radioactive elements in the Finnish bedrock are of great relevance to the Finnish nuclear waste disposal programme. It indicates the likely fate of radionuclides released from the deep repository when the chemical environment is oxidizing within its operating stage or in the event of glacial melt water percolates to the repository. In these conditions the uranium occurs in its +6 state, and it is reactive and mobile. Studying uranium migration and retention in oxidizing conditions is thus justified. Uranium migration and retention are studied with samples taken from a natural uranium deposit at Askola. Likewise the uranium migration is studied with laboratory tests. The naturally uranium-rich samples are taken from shallow depths at Askola, and thus the behaviour of uranium can be studied in oxidising conditions. In the laboratory tests uranium is released from a depleted uranium disc and allowed to migrate and retain in Kuru grey granite and Sievi altered tonalite. The uranium is expected to migrate into the rock and to precipitate there as secondary phases. The rate of uranium migration and age of the precipitates in the laboratory experiments are known, but not in the case of the natural analogue studies. The observations from both the natural analogue and the laboratory tests will be used as input data for the coupled geochemical model for uranium migration and retention. (orig.)

  9. Remediation of Uranium in the Hanford Vadose Zone Using Ammonia Gas: FY 2010 Laboratory-Scale Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, James E.; Truex, Michael J.; Zhong, Lirong; Qafoku, Nikolla; Williams, Mark D.; McKinley, James P.; Wang, Zheming; Bargar, John; Faurie, Danielle K.; Resch, Charles T.; Phillips, Jerry L.

    2010-12-01

    This investigation is focused on refining an in situ technology for vadose zone remediation of uranium by the addition of ammonia (NH3) gas. Objectives are to: a) refine the technique of ammonia gas treatment of low water content sediments to minimize uranium mobility by changing uranium surface phases (or coat surface phases), b) identify the geochemical changes in uranium surface phases during ammonia gas treatment, c) identify broader geochemical changes that occur in sediment during ammonia gas treatment, and d) predict and test injection of ammonia gas for intermediate-scale systems to identify process interactions that occur at a larger scale and could impact field scale implementation.Overall, NH3 gas treatment of low-water content sediments appears quite effective at decreasing aqueous, adsorbed uranium concentrations. The NH3 gas treatment is also fairly effective for decreasing the mobility of U-carbonate coprecipitates, but shows mixed success for U present in Na-boltwoodite. There are some changes in U-carbonate surface phases that were identified by surface phase analysis, but no changes observed for Na-boltwoodite. It is likely that dissolution of sediment minerals (predominantly montmorillonite, muscovite, kaolinite) under the alkaline conditions created and subsequent precipitation as the pH returns to natural conditions coat some of the uranium surface phases, although a greater understanding of these processes is needed to predict the long term impact on uranium mobility. Injection of NH3 gas into sediments at low water content (1% to 16% water content) can effectively treat a large area without water addition, so there is little uranium mobilization (i.e., transport over cm or larger scale) during the injection phase.

  10. New Observations of the Attachment Process in Natural Lightning

    Science.gov (United States)

    Tran, M. D.; Rakov, V. A.; Mallick, S.

    2015-12-01

    We examined the natural-lightning attachment process using high-speed (HS) video records in conjunction with electric field and electric field derivative measurements, all obtained at the Lightning Observatory in Gainesville (LOG), Florida. In different types of strokes (negative first, negative subsequent, and positive first), we observed faintly luminous formations (FLFs) connecting the downward leader to ground. The 2-D lengths of FLFs ranged from 51 to 200 m in negative first strokes (N = 11), from 130 to 908 m in negative subsequent strokes (N=5), and it was 177 m in 1 positive first stroke. The nature of FLFs in negative first strokes differs from that in negative subsequent strokes. We inferred that in first strokes FLFs are mostly composed of positive streamers that developed from the prospective strike point (without a significant upward connecting leader), tens of microseconds prior to the return-stroke onset, while in subsequent strokes they are manifestations of elevated conduction current (of the order of 1 A) in the weakly-conducting defunct channel, occurring in response to the increasing average electric field of the descending leader. The FLF in the positive stroke appeared to be similar to its counterparts in negative first strokes. The streamer connection of the first-stroke leader tip to ground constitutes the break-through phase of the attachment process. Establishment of this connection tens of microseconds prior to the lightning return-stroke onset has never been reported before. We found that the streamer connection did not significantly influence the propagation characteristics of descending leader (and the upward connecting leader, if any), except for always guiding it to the origin of streamers on the grounded object. Implications of the new observations for lightning protection will be discussed. AcknowledgementsThis research was supported in part by NSF and DARPA.

  11. Challenges to natural process restoration: common dam removal management concerns

    Science.gov (United States)

    Collins, M. J.; Tullos, D. D.; Bellmore, J. R.; Bountry, J.; Connolly, P. J.; Shafroth, P. B.; Wilcox, A. C.

    2015-12-01

    Practitioners must make dam removal decisions in spite of uncertainty about physical and ecological responses. This can result in implementing structural controls or other interventions at a site to avoid anticipated negative effects, sometimes even if a given concern is not warranted. We used a newly available dam removal science database and other information sources to explore seven frequently raised issues we call "Common Management Concerns" (CMCs), investigating their occurrence and the contributing biophysical controls. We describe these controls to enable managers to better assess if further analyses are warranted at their sites before interventions are planned and implemented. The CMCs addressed are: rate and degree of reservoir sediment erosion; drawdown impacts on local water infrastructure; excessive channel incision; downstream sediment aggradation; elevated turbidity; colonization of reservoir sediments by non-native plants; and expansion of invasive fish. The relative dearth of case studies available for many CMCs limited the generalizable conclusions we could draw about prevalence, but the available data and established understanding of relevant processes revealed important biophysical phenomena controlling the likelihood of CMC occurrence. To assess CMC risk, we recommend managers concurrently evaluate if site conditions suggest the ecosystem, infrastructure, or other human uses will be negatively affected if the biophysical phenomenon producing the CMC occurs. We show how many CMCs have one or more controls in common, facilitating the identification of multiple risks at a site, and demonstrate why CMC risks should be considered in the context of other important factors like watershed disturbance history, natural variability, and dam removal tradeoffs. Better understanding CMCs and how to evaluate them will enable practitioners to avoid unnecessary interventions and thus maximize opportunities for working with natural processes to restore river

  12. 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.

  13. Conversion of Molybdenum-99 production process to low enriched uranium: Neutronic and thermal hydraulic analyses of HEU and LEU target plates for irradiation in Pakistan Research Reactor-1

    Science.gov (United States)

    Mushtaq, Ahmad; Iqbal, Masood; Bokhari, Ishtiaq Hussain; Mahmood, Tayyab; Muhammad, Atta

    2012-09-01

    Technetium-99m, the daughter product of Molybdenum-99 is the most widely needed radionuclide for diagnostic studies in Pakistan. Molybdenum-99 Production Facility has been established at PINSTECH. Highly enriched uranium (93% 235U) U/Al alloy targets have been irradiated in Pakistan Research Reactor-1 (PARR-1) for the generation of fission Mo-99, while basic dissolution technique is used for separation of Mo-99 from target matrix activity. In line with the international objective of minimizing and eventually eliminating the use of HEU in civil commerce, national and international efforts have been underway to shift the production of medical isotopes from HEU to LEU (LEU; uranium is needed. LEU aluminum uranium dispersion target has been developed, which may replace existing HEU aluminum/uranium alloy targets for production of 99Mo using basic dissolution technique. Neutronic and thermal hydraulic calculations were performed for safe irradiation of targets in the core of PARR-1.

  14. A common type system for clinical natural language processing.

    Science.gov (United States)

    Wu, Stephen T; Kaggal, Vinod C; Dligach, Dmitriy; Masanz, James J; Chen, Pei; Becker, Lee; Chapman, Wendy W; Savova, Guergana K; Liu, Hongfang; Chute, Christopher G

    2013-01-03

    One challenge in reusing clinical data stored in electronic medical records is that these data are heterogenous. Clinical Natural Language Processing (NLP) plays an important role in transforming information in clinical text to a standard representation that is comparable and interoperable. Information may be processed and shared when a type system specifies the allowable data structures. Therefore, we aim to define a common type system for clinical NLP that enables interoperability between structured and unstructured data generated in different clinical settings. We describe a common type system for clinical NLP that has an end target of deep semantics based on Clinical Element Models (CEMs), thus interoperating with structured data and accommodating diverse NLP approaches. The type system has been implemented in UIMA (Unstructured Information Management Architecture) and is fully functional in a popular open-source clinical NLP system, cTAKES (clinical Text Analysis and Knowledge Extraction System) versions 2.0 and later. We have created a type system that targets deep semantics, thereby allowing for NLP systems to encapsulate knowledge from text and share it alongside heterogenous clinical data sources. Rather than surface semantics that are typically the end product of NLP algorithms, CEM-based semantics explicitly build in deep clinical semantics as the point of interoperability with more structured data types.

  15. A common type system for clinical natural language processing

    Directory of Open Access Journals (Sweden)

    Wu Stephen T

    2013-01-01

    Full Text Available Abstract Background One challenge in reusing clinical data stored in electronic medical records is that these data are heterogenous. Clinical Natural Language Processing (NLP plays an important role in transforming information in clinical text to a standard representation that is comparable and interoperable. Information may be processed and shared when a type system specifies the allowable data structures. Therefore, we aim to define a common type system for clinical NLP that enables interoperability between structured and unstructured data generated in different clinical settings. Results We describe a common type system for clinical NLP that has an end target of deep semantics based on Clinical Element Models (CEMs, thus interoperating with structured data and accommodating diverse NLP approaches. The type system has been implemented in UIMA (Unstructured Information Management Architecture and is fully functional in a popular open-source clinical NLP system, cTAKES (clinical Text Analysis and Knowledge Extraction System versions 2.0 and later. Conclusions We have created a type system that targets deep semantics, thereby allowing for NLP systems to encapsulate knowledge from text and share it alongside heterogenous clinical data sources. Rather than surface semantics that are typically the end product of NLP algorithms, CEM-based semantics explicitly build in deep clinical semantics as the point of interoperability with more structured data types.

  16. A new procedure for Uranium fractionation

    Energy Technology Data Exchange (ETDEWEB)

    Costas Costas, E.; Baselga Cervara, B.; Tarin garcia, F.

    2014-07-01

    Nowadays only few procedures are employed for uranium fractionation, all of them at physico-chemical level. Ideally, we would develop a procedure based in a von Neumann machines (a rapid self-replicating machine capable of perform the uranium fractionation). Microorganism behave as von Newmann machines and al l known enzymatic processes are able to isotopic fractionation, often enriching the living organism in the lighter isotope. (Author)

  17. The ultimate disposition of depleted uranium

    Energy Technology Data Exchange (ETDEWEB)

    Lemons, T.R. [Uranium Enrichment Organization, Oak Ridge, TN (United States)

    1991-12-31

    Depleted uranium (DU) is produced as a by-product of the uranium enrichment process. Over 340,000 MTU of DU in the form of UF{sub 6} have been accumulated at the US government gaseous diffusion plants and the stockpile continues to grow. An overview of issues and objectives associated with the inventory management and the ultimate disposition of this material is presented.

  18. Chemical thermodynamics of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Grenthe, I.; Fuger, J.; Lemire, R.J.; Muller, A.B.; Nguyen-Trung Cregu, C.; Wanner, H.

    1992-01-01

    A comprehensive overview on the chemical thermodynamics of those elements that are of particular importance in the safety assessment of radioactive waste disposal systems is provided. This is the first volume in a series of critical reviews to be published on this subject. The book provides an extensive compilation of chemical thermodynamic data for uranium. A description of procedures for activity corrections and uncertainty estimates is given. A critical discussion of data needed for nuclear waste management assessments, including areas where significant gaps of knowledge exist is presented. A detailed inventory of chemical thermodynamic data for inorganic compounds and complexes of uranium is listed. Data and their uncertainty limits are recommended for 74 aqueous complexes and 199 solid and 31 gaseous compounds containing uranium, and on 52 aqueous and 17 solid auxiliary species containing no uranium. The data are internally consistent and compatible with the CODATA Key Values. The book contains a detailed discussion of procedures used for activity factor corrections in aqueous solution, as well as including methods for making uncertainty estimates. The recommended data have been prepared for use in environmental geochemistry. Containing contributions written by experts the chapters cover various subject areas such a s: oxide and hydroxide compounds and complexes, the uranium nitrides, the solid uranium nitrates and the arsenic-containing uranium compounds, uranates, procedures for consistent estimation of entropies, gaseous and solid uranium halides, gaseous uranium oxides, solid phosphorous-containing uranium compounds, alkali metal uranates, uncertainties, standards and conventions, aqueous complexes, uranium minerals dealing with solubility products and ionic strength corrections. The book is intended for nuclear research establishments and consulting firms dealing with uranium mining and nuclear waste disposal, as well as academic and research institutes.

  19. Ultrasensitive techniques for measurement of uranium in biological samples and the nephrotoxicity of uranium: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Kathren, R.L.; Weber, J.R. (eds.)

    1988-04-01

    Edited transcripts are provided of two public meetings sponsored by the Division of Radiation Programs and Earth Sciences of the Nuclear Regulatory Commission, Occupational Radiation Protection Branch. The first meeting, held on December 3, 1985, included nine presentations covering ultrasensitive techniques for measurement of uranium in biological specimens. Topics included laser-spectrometric techniques for uranium bioassay, correlation of urinary uranium samples with air sampling results in industrial settings, delayed neutron counting, laser-kinetic phosphometry, isotope dilution mass spectrometry, resonance ionization spectroscopy, fission track analysis, laser-induced fluorescence, and costs of sampling and processing. The nine presentations of the second meeting dealt with the nephrotoxicity of uranium. Among the topics presented were the physiology of the kidney, the effects of heavy metals on the kidney, animal studies in uranium nephrotoxicity, comparisons of kidney histology in nine humans, renal effects in uranium mill workers, renal damage from different uranium isotopes, and Canadian studies on uranium toxicity. Discussions following the presentations are included in the edited transcripts. 30 refs., 9 figs., 9 tabs.

  20. Bark, a suitable bio-sorbent for the removal of uranium from wastewater - From laboratory to industry

    Energy Technology Data Exchange (ETDEWEB)

    Jauberty, L.; Delpech, V. [Laboratoire de Chimie des Substances Naturelles EA1069, Faculte des Sciences et Techniques, 123 avenue Albert Thomas, 87060 Limoges (France); PearL SAS, 83 rue d' Isle, 87000 Limoges (France); Gloaguen, V.; Astier, C.; Krausz, P. [Laboratoire de Chimie des Substances Naturelles EA1069, Faculte des Sciences et Techniques, 123 avenue Albert Thomas, 87060 Limoges (France); Berland, A.; Granger, V.; Niort, I.; Royer, A.; Decossas, J.L. [PearL SAS, 83 rue d' Isle, 87000 Limoges (France)

    2011-07-01

    This paper shows that natural materials such as barks can successfully replace synthetic resins for industrial purposes. Evaluated in batch conditions, bio-sorption of uranium on suitably prepared Douglas fir barks took place in less than 10 min and appeared to be optimum at pH>4. The bio-sorption process of uranium (uranyl form UO{sub 2}{sup 2+}) was characterized in the optimal physico-chemical conditions and could be mathematically modeled as a Langmuir isotherm. With a maximum uranium specific uptake q{sub max} value of 1.16 meq.g{sup -1} (138 mgU.g{sup -1}) it was found that the sorption capability of Douglas fir barks was at least five times higher for uranium than for other heavy metals such as lead. Adsorption of uranium contained in water leached from a former uranium mine was then monitored over a one-month period in a laboratory-scale chromatography column. The fixation capacity remained fairly constant throughout the whole testing period. Water radioactivity decreased from 1500 mBq.L{sup -1} (0.12 mgU.L{sup -1}) to <5 mBq.L{sup -1} (0.4 {mu}gU.L{sup -1}) at the column exit. This technology was successfully transferred and tested through a pilot project under industrial conditions with the support of AREVA NC. (authors)

  1. Fractal and Chaos Analysis for Dynamics of Radon Exhalation from Uranium Mill Tailings

    Science.gov (United States)

    Li, Yongmei; Tan, Wanyu; Tan, Kaixuan; Liu, Zehua; Xie, Yanshi

    2016-08-01

    Tailings from mining and milling of uranium ores potentially are large volumes of low-level radioactive materials. A typical environmental problem associated with uranium tailings is radon exhalation, which can significantly pose risks to environment and human health. In order to reduce these risks, it is essential to study the dynamical nature and underlying mechanism of radon exhalation from uranium mill tailings. This motivates the conduction of this study, which is based on the fractal and chaotic methods (e.g. calculating the Hurst exponent, Lyapunov exponent and correlation dimension) and laboratory experiments of the radon exhalation rates. The experimental results show that the radon exhalation rate from uranium mill tailings is highly oscillated. In addition, the nonlinear analyses of the time series of radon exhalation rate demonstrate the following points: (1) the value of Hurst exponent much larger than 0.5 indicates non-random behavior of the radon time series; (2) the positive Lyapunov exponent and non-integer correlation dimension of the time series imply that the radon exhalation from uranium tailings is a chaotic dynamical process; (3) the required minimum number of variables should be five to describe the time evolution of radon exhalation. Therefore, it can be concluded that the internal factors, including heterogeneous distribution of radium, and randomness of radium decay, as well as the fractal characteristics of the tailings, can result in the chaotic evolution of radon exhalation from the tailings.

  2. Toxicity of uranium on renal cells

    Energy Technology Data Exchange (ETDEWEB)

    Thiebault, C.; Carriere, M.; Gouget, B. [CEA Saclay, CNRS, UMR9956, Lab Pierre Sue, F-91191 Gif Sur Yvette, (France)

    2007-07-01

    Kidney and bone are the main retention organs affected by uranium toxicity. Although the clinical effects of uranium poisoning are well known, only few studies dealt with cellular mechanisms of toxicity. The purpose of this study was to investigate the cyto- and genotoxicity of uranium (U) on renal cells. The cell death was also studied in this conditions of exposure. The effects of U were evaluated in acute and chronic exposure. The acute effects were evaluated after 24 h exposure to strong U concentrations (200-700{mu}M). The chronic exposure was observed on renal cells incubated with low U concentrations (0.1-100 {mu}M) until 70 days then with high uranium concentrations (400-500 {mu}M) during 24 h. U induces apoptosis cell death mainly by the intrinsic pathway. The high U concentrations (600-700 {mu}M) lead to necrosis. U induces DNA damages (single, double strand breaks, as well as alkali labile sites) from 300{mu}M. The cytotoxicity and intracellular accumulation of uranium were less important in cells previously exposed to low uranium concentrations when compared to non-exposed cells. In the same time, DNA damage observed after acute exposure of uranium decreased with the increase of chronic uranium concentrations. These results suggest that renal cells became resistant to uranium, probably due to a cellular transformation process. In conclusion, high U concentrations (300-700{mu}M) induce apoptosis cell death and DNA damages. Cells previously exposed to low U concentrations present also DNA damages and a cellular transformation. (authors)

  3. Natural Language Processing and Fuzzy Tools for Business Processes in a Geolocation Context

    Directory of Open Access Journals (Sweden)

    Isis Truck

    2017-01-01

    Full Text Available In the geolocation field where high-level programs and low-level devices coexist, it is often difficult to find a friendly user interface to configure all the parameters. The challenge addressed in this paper is to propose intuitive and simple, thus natural language interfaces to interact with low-level devices. Such interfaces contain natural language processing (NLP and fuzzy representations of words that facilitate the elicitation of business-level objectives in our context. A complete methodology is proposed, from the lexicon construction to a dialogue software agent including a fuzzy linguistic representation, based on synonymy.

  4. Naturalness judgments by lay Americans: Process dominates content in judgments of food or water acceptability and naturalness

    OpenAIRE

    2006-01-01

    This study directly tests the hypothesis that, at least within the domains of food and drink for Americans, the judgment of naturalness has more to do with the history of an object, that is the processes that it has undergone, as opposed to its material content. Individuals rate the naturalness and acceptability of a natural entity (water or tomato paste), that same entity with a first transformation in which a natural substance is added (or some part removed), and then a second transformatio...

  5. METHOD OF ROLLING URANIUM

    Science.gov (United States)

    Smith, C.S.

    1959-08-01

    A method is described for rolling uranium metal at relatively low temperatures and under non-oxidizing conditions. The method involves the steps of heating the uranium to 200 deg C in an oil bath, withdrawing the uranium and permitting the oil to drain so that only a thin protective coating remains and rolling the oil coated uranium at a temperature of 200 deg C to give about a 15% reduction in thickness at each pass. The operation may be repeated to accomplish about a 90% reduction without edge cracking, checking or any appreciable increase in brittleness.

  6. The potential human health effect(s) of the metal uranium in the environment. Report on the known human health effects associated with the exposure to the metal uranium

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-31

    Concern over the levels of the metal uranium in the environment as a result of industrial activities has been expressed by several Federal and State agencies. This concern is associated with potential human health effects of this metal on kidney function and bone formation. Although limits for the Metal uranium in the environment remain to be set, the Environmental Protection Agency (EPA) is currently in the process of establishing guidance limits for this metal in water and soil. These limits will be established for both the metal and the associated radioactivity. The suggested limits currently being considered for water and soil are, 20 pCi/liter and 10 pCi/gram wet weight, respectively. For naturally occurring uranium EPA assumes that 1 ug of uranium metal equals 0.67 pCi at equilibrium (i.e. at equilibrium the mass ratio of {sup 234}uranium to {sup 238}uranium is small but their activities are equal). Thus the limits for water and soil on weight basis for the uranium metal would be 30 ug/liter and 15 ug/gram wet weight, respectively. These limits are being established based on the potential increase in cancer death in populations that exceed this limit. Since there does not appear to be a significant correlation between cancer deaths and.uranium metal exposure (see discussion below), these limits will probably be established based on the known association between radionuclides exposure and cancer deaths. The exposure limits for other health effects such as kidney damage and retardation in bone formation apparently are not being considered by EPA.

  7. The Application of Reconstruction Prediction Technology of Chaotic Phase Space in Heap Leaching Process of Uranium Ores%混沌相空间重构预测技术在铀矿堆浸中的应用

    Institute of Scientific and Technical Information of China (English)

    韩静; 刘光萍

    2012-01-01

    将混沌理论引入到铀矿堆浸工艺中,分析工艺中产生的数据,得出铀矿堆浸工艺具有混沌特性的结论,并在此基础上,应用新的局部预测方法,对铀矿的累计浸出率进行了几组多维预测分析,为建立合理的堆浸工艺数学模型提供了新的思路.%The chaos theory is applied to the heap leaching process of uranium ores. The analysis on the data generated in the process showed that the heap leaching process of uranium has chaotic property. Based on this, several groups of multi-dimensional prediction analysis on the uranium extraction rate are made by using an new local forecasting method. It provides a new concept to establish a reasonable mathematical model in heap leaching process.

  8. Fluorinated compounds in the uranium conversion process: risk analysis and proposition of pictograms; Os compostos fluorados nos processos da conversao do uranio: analise de riscos e proposicao de pictogramas

    Energy Technology Data Exchange (ETDEWEB)

    Jeronimo, Adroaldo Clovis; Oliveira, Wagner dos Santos, E-mail: acejota18@yahoo.com.br, E-mail: oliveira@feq.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Quimica; Aquino, Afonso Rodrigues de, E-mail: araquino@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-03-15

    In the process of uranium hexafluoride production there are risks that must be taken into account since the time of completing the project chemist, in its conceptual stage, until to the stage of detailed design and are associated with the handling of chemicals, especially fluoride hydrogen and fluorine. This paper aims to address issues related to the prevention of risks related to industrial safety and health and the environment, considering the different stages of the uranium conversion. Take into account the safety warnings of the plant and, accordingly, make the proposition of pictograms adequate to alert operators of care to be taken during the proposition of pictograms adequate to alert operators of care to be taken during the conduct of these chemical processes. (author)

  9. 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 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.

  10. Resin-based preparation of HTGR fuels: operation of an engineering-scale uranium loading system

    Energy Technology Data Exchange (ETDEWEB)

    Haas, P.A.

    1977-10-01

    The fuel particles for recycle of /sup 233/U to High-Temperature Gas-Cooled Reactors are prepared from uranium-loaded carboxylic acid ion exchange resins which are subsequently carbonized, converted, and refabricated. The development and operation of individual items of equipment and of an integrated system are described for the resin-loading part of the process. This engineering-scale system was full scale with respect to a hot demonstration facility, but was operated with natural uranium. The feed uranium, which consisted of uranyl nitrate solution containing excess nitric acid, was loaded by exchange with resin in the hydrogen form. In order to obtain high loadings, the uranyl nitrate must be acid deficient; therefore, nitric acid was extracted by a liquid organic amine which was regenerated to discharge a NaNO/sub 3/ or NH/sub 4/NO/sub 3/ solution waste. Water was removed from the uranyl nitrate solution by an evaporator that yielded condensate containing less than 0.5 ppM of uranium. The uranium-loaded resin was washed with condensate and dried to a controlled water content via microwave heating. The loading process was controlled via in-line measurements of the pH and density of the uranyl nitrate. The demonstrated capacity was 1 kg of uranium per hour for either batch loading contractors or a continuous column as the resin loading contractor. Fifty-four batch loading runs were made without a single failure of the process outlined in the chemical flowsheet or any evidence of inability to control the conditions dictated by the flowsheet.

  11. Experimental design and optimization of leaching process for recovery of valuable chemical elements (U, La, V, Mo, Yb and Th) from low-grade uranium ore.

    Science.gov (United States)

    Zakrzewska-Koltuniewicz, Grażyna; Herdzik-Koniecko, Irena; Cojocaru, Corneliu; Chajduk, Ewelina

    2014-06-30

    The paper deals with experimental design and optimization of leaching process of uranium and associated metals from low-grade, Polish ores. The chemical elements of interest for extraction from the ore were U, La, V, Mo, Yb and Th. Sulphuric acid has been used as leaching reagent. Based on the design of experiments the second-order regression models have been constructed to approximate the leaching efficiency of elements. The graphical illustrations using 3-D surface plots have been employed in order to identify the main, quadratic and interaction effects of the factors. The multi-objective optimization method based on desirability approach has been applied in this study. The optimum condition have been determined as P=5 bar, T=120 °C and t=90 min. Under these optimal conditions, the overall extraction performance is 81.43% (for U), 64.24% (for La), 98.38% (for V), 43.69% (for Yb) and 76.89% (for Mo) and 97