WorldWideScience

Sample records for ceramic grade uranium

  1. Reactivity of ceramic coating materials with uranium and uranium trichlorid

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Ho; Cho, Choon Ho; Lee, Yoon Sang; Lee, Han Soo; Kim, Jeong Guk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-05-15

    Uranium and uranium alloys are typically induction melted in graphite crucibles under a vacuum. The graphite crucible is used for the manufacturing of uranium ingots in the casting equipment. But, due to the chemical reactivity of uranium and most alloying elements with carbon, a protective ceramic coating is generally applied to the crucibles. In this study, to investigate the most suitable ceramic coating material applied to graphite melting crucibles and ingot moldsused in the melting and casting of uranium in the casting equipment, firstly, the thermodynamic analysis was performed by using HSC software to investigate the reactivity between uranium and several ceramic materials and the experiments on the reaction of ceramic coated crucibles in molten uranium were carried out at 1300 .deg. C

  2. Yellow cake to ceramic uranium dioxide

    International Nuclear Information System (INIS)

    This overview article first reviews the processes for converting uranium ore concentrates to ceramic uranium dioxide at the Port Hope Refinery of Eldorado Resources Limited. In addition, some of the problems, solutions, thoughts and research direction with respect to the production and properties of ceramic UO2 are described

  3. Graded Structures for All-ceramic Restorations

    OpenAIRE

    Zhang, Y.; Chai, H.; Lawn, B.R.

    2010-01-01

    One failure mode of all-ceramic restorations is radial cracking at the cementation surface, from occlusally induced flexure of the stiffer ceramic layer(s) on the softer dentin underlayer. We hypothesize that such failure may be substantially mitigated by an appropriate grading of elastic modulus through the ceramic thickness. In this study, we fabricated graded structures by infiltrating glass into zirconia plates, with resulting diminished modulus in the outer surfaces. The plates were then...

  4. Graded structures for all-ceramic restorations.

    Science.gov (United States)

    Zhang, Y; Chai, H; Lawn, B R

    2010-04-01

    One failure mode of all-ceramic restorations is radial cracking at the cementation surface, from occlusally induced flexure of the stiffer ceramic layer(s) on the softer dentin underlayer. We hypothesize that such failure may be substantially mitigated by an appropriate grading of elastic modulus through the ceramic thickness. In this study, we fabricated graded structures by infiltrating glass into zirconia plates, with resulting diminished modulus in the outer surfaces. The plates were then bonded to a polymeric base and subjected to flexure by contact loading until fracture. Comparison of infiltrated specimens with non-infiltrated controls showed a significant increase in the fracture loads, by a factor of nearly 2. Finite element analysis revealed the cause of increase in the load-bearing capacity to be diminished tensile stresses within the lower-modulus graded zone, corresponding to an increase in material strength. The results confirmed that suitably graded structures can be highly beneficial in the design of next-generation all-ceramic restorations. PMID:20200413

  5. Uranium mobilization from low-grade ore by cyanobacteria

    International Nuclear Information System (INIS)

    Three cyanobacterial isolates (two LPP-B forms and one Anabaena or Nostoc species) from different environments could mobilize uranium from low-grade ores. After 80 days, up to 18% uranium had been extracted from coal and 51% from a carbonate rock by the filamentous cyanobacterium OL3, a LPP-B form. Low growth requirements with regard to light and temperature optima make this strain a possible candidate for leaching neutral and alkaline low-grade uranium ores. (orig.)

  6. Ceramic/polymer functionally graded material (FGM) lightweight armor system

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, J.J.; McClellan, K.J.

    1998-12-31

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Functionally graded material is an enabling technology for lightweight body armor improvements. The objective was to demonstrate the ability to produce functionally graded ceramic-polymer and ceramic-metal lightweight armor materials. This objective involved two aspects. The first and key aspect was the development of graded-porosity boron-carbide ceramic microstructures. The second aspect was the development of techniques for liquid infiltration of lightweight metals and polymers into the graded-porosity ceramic. The authors were successful in synthesizing boron-carbide ceramic microstructures with graded porosity. These graded-porosity boron-carbide hot-pressed pieces were then successfully liquid-infiltrated in vacuum with molten aluminum at 1,300 C, and with liquid polymers at room temperature. Thus, they were able to demonstrate the feasibility of producing boron carbide-aluminum and boron carbide-polymer functionally graded materials.

  7. Low grade uranium deposits of India - a bane or boon

    International Nuclear Information System (INIS)

    Uranium resources of the world is estimated to be 5.5 million tonnes and the proven resources in India forms 3% of the world resources. The biggest uranium deposit is the Olympic dam deposit in Australia, which contains nearly one million tonnes of 0.04% U3O8, while the highest grade of nearly 20% is established in the McArthur river deposit, Canada. Another very high grade deposit, the Cigar lake deposit, is established in Canada with an average grade of nearly 18%. Most of the uranium deposits established in India so far falls under the category of low grade. These low grade uranium deposits are distributed mainly in Singhbhum Shear Zone, eastern India; in parts of Chhattisgarh; Southern parts of Meghalaya; Cuddapah Basin, Andhra Pradesh; in parts of Karnataka and Aravalli- and Delhi Supergroups, Rajasthan and Haryana. These deposits are mainly hydrothermal vein type, stratabound type and unconformity related. The Singhbhum Shear Zone, Jharkhand hosts a seventeen low grade uranium deposits, aggregating about 30% of Indian uranium resources. The uranium mineralisation hosted by Vempalle dolostone extends over 160 km belt along southwestern margin of Cuddapah Basin in Andhra Pradesh and accounts 23% of the Indian resources. Though the dolostone hosted Tummalapalle uranium deposit was established in the early nineties, because of techno-economic constraints, the deposit remained dormant. As a consequence of the development of an innovative pressure alkali beneficiation process, the deposit became economically viable and a mine and mill are being constructed here. Recent exploration inputs are leading to prove a number of low grade uranium deposits in the extension areas of Tummalapalle. Nearly 10 blocks have been identified within a 30 km belt which are being actively explored and a large uranium deposit has already been proved in this province. The deposit at Tummalapalle and adjoining areas is likely to become the second biggest deposit in the world. The northern

  8. Overview: Damage resistance of graded ceramic restorative materials.

    Science.gov (United States)

    Zhang, Yu

    2012-08-01

    Improving mechanical response of materials is of great interest in a wide range of disciplines, including biomechanics, tribology, geology, optoelectronics, and nanotechnology. It has been long recognized that spatial gradients in surface composition and structure can improve the mechanical integrity of a material. This review surveys recent results of sliding-contact, flexural, and fatigue tests on graded ceramic materials from our laboratories and elsewhere. Although our findings are examined in the context of possible applications for next-generation, graded all-ceramic dental restorations, implications of our studies have broad impact on biomedical, civil, structural, and an array of other engineering applications.

  9. Processing of low grade uranium ores

    International Nuclear Information System (INIS)

    Four types of low-grade ores are studied: (1) Low-grade ores that must be extracted because they are enclosed in a normal-grade deposit. Heap leaching is the processing method which is largely used. (2) Normal-grade ores contained in low-amplitude deposits. They can be processed using in-place leaching as far as the operation does not need any large and expensive equipment. (3) Medium-grade ores in medium-amplitude deposits. A simplified conventional process can be applied using fast heap leaching. (4) Low-grade ores in large deposits. The report explains processing possibilities leading in most cases to the use of in-place leaching. The operating conditions of this method are laid out, especially the selection of the leaching agents and the preparation of the ore deposit

  10. Estimation of intermediate grade uranium resources. Final report

    International Nuclear Information System (INIS)

    The purpose of this project is to analyze the technique currently used by DOE to estimate intermediate grade uranium (0.01 to 0.05% U3O8) and, if possible, suggest alternatives to improve the accuracy and precision of the estimate. There are three principal conclusions resulting from this study. They relate to the quantity, distribution and sampling of intermediate grade uranium. While the results of this study must be validated further, they indicate that DOE may be underestimating intermediate level reserves by 20 to 30%. Plots of grade of U3O8 versus tonnage of ore and tonnage U3O8 indicate grade-tonnage relationships that are essentially log-linear, at least down to 0.01% U3O8. Though this is not an unexpected finding, it may provide a technique for reducing the uncertainty of intermediate grade endowment. The results of this study indicate that a much lower drill hole density is necessary for DOE to estimate uranium resources than for a mining company to calculate ore resources. Though errors in local estimates will occur, they will tend to cancel over the entire deposit

  11. Real-time surface grading of ceramic tiles

    OpenAIRE

    López García, Fernando

    2008-01-01

    This thesis presents a case of study of the development and performance analysis of a surface grading application with real-time compliance. We address the issue of spatial and temporal uniformity in the acquisition system. In a surface grading application it is crucial to ensure the uniform response of the system through time and space. All the results presented for surface grading were obtained using real data from the ceramic tile industry. The VxC TSG database is public and can be...

  12. Continued Multicolumns Bioleaching for Low Grade Uranium Ore at a Certain Uranium Deposit

    Directory of Open Access Journals (Sweden)

    Gongxin Chen

    2016-01-01

    Full Text Available Bioleaching has lots of advantages compared with traditional heap leaching. In industry, bioleaching of uranium is still facing many problems such as site space, high cost of production, and limited industrial facilities. In this paper, a continued column bioleaching system has been established for leaching a certain uranium ore which contains high fluoride. The analysis of chemical composition of ore shows that the grade of uranium is 0.208%, which is lower than that of other deposits. However, the fluoride content (1.8% of weight is greater than that of other deposits. This can be toxic for bacteria growth in bioleaching progress. In our continued multicolumns bioleaching experiment, the uranium recovery (89.5% of 4th column is greater than those of other columns in 120 days, as well as the acid consumption (33.6 g/kg. These results indicate that continued multicolumns bioleaching technology is suitable for leaching this type of ore. The uranium concentration of PLS can be effectively improved, where uranium recovery can be enhanced by the iron exchange system. Furthermore, this continued multicolumns bioleaching system can effectively utilize the remaining acid of PLS, which can reduce the sulfuric acid consumption. The cost of production of uranium can be reduced and this benefits the environment too.

  13. Overview: Damage resistance of graded ceramic restorative materials

    OpenAIRE

    Zhang, Yu

    2012-01-01

    Improving mechanical response of materials is of great interest in a wide range of disciplines, including biomechanics, tribology, geology, optoelectronics, and nanotechnology. It has been long recognized that spatial gradients in surface composition and structure can improve the mechanical integrity of a material. This review surveys recent results of sliding-contact, flexural, and fatigue tests on graded ceramic materials from our laboratories and elsewhere. Although our findings are examin...

  14. Functionally Graded Ceramics Fabricated with Side-by-Side Tape Casting for Use in Magnetic Refrigeration

    DEFF Research Database (Denmark)

    Bulatova, Regina; Bahl, Christian; Andersen, Kjeld Bøhm;

    2015-01-01

    Functionally graded ceramic tapes have been fabricated by a side-by-side tape casting technique. This study shows the possibility and describes the main principles of adjacent coflow of slurries resulting in formation of thin plates of graded ceramic material. Results showed that the small variat...

  15. Natural radionuclides in commodities, for example uranium containing glassware and ceramics

    International Nuclear Information System (INIS)

    Both in private households and public buildings as well as in the building materials trade, uranium containing glassware, tiles, or ceramics are found. The article reports approaches for assessing the possible radiation exposure involved and discusses the German radiation protection ordinance, as last amended, with respect to coverage of possible radiation exposure due to such materials. (orig./CB)

  16. Status Report from the United Kingdom [Processing of Low-Grade Uranium Ores

    International Nuclear Information System (INIS)

    The invitation to present this status report could have been taken literally as a request for information on experience gained in the actual processing of low-grade uranium ores in the United Kingdom, in which case there would have been very little to report; however, the invitation naturally was considered to be a request for a report on the experience gained by the United Kingdom of the processing of uranium ores. Lowgrade uranium ores are not treated in the United Kingdom simply because the country does not possess any known significant deposits of uranium ore. It is of interest to record the fact that during the nineteenth century mesothermal vein deposits associated with Hercynian granite were worked at South Terras, Cornwall, and ore that contained approximately 100 tons of uranium oxide was exported to Germany. Now only some 20 tons of contained uranium oxide remain at South Terras; also in Cornwall there is a small number of other vein deposits that each hold about five tons of uranium. Small lodes of uranium ore have been located in the southern uplands of Scotland; in North Wales lower palaeozoic black shales have only as much as 50 to 80 parts per million of uranium oxide, and a slightly lower grade carbonaceous shale is found near the base of the millstone grit that occurs in the north of England. Thus the experience gained by the United Kingdom has been of the treatment of uranium ores that occur abroad.

  17. Fabrication of uranium dioxide ceramic pellets with controlled porosity from oxide microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Remy, E. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Picart, S., E-mail: sebastien.picart@cea.fr [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Delahaye, T. [Fuel Cycle Technology Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Jobelin, I. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Dugne, O. [Fuel Cycle Technology Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Bisel, I. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Blanchart, P. [Heterogeneous Materials Research Group, Centre Européen de la Céramique, F-87068 Limoges (France); Ayral, A. [Institut Européen des Membranes, UMR 5635 CNRS-ENSCM-UM2, University of Montpellier, F-34095 Montpellier cedex 5 (France)

    2014-05-01

    This study concerns the fabrication of uranium oxide pellets using the powder-free process called Calcined Resin Microsphere Pelletization (CRMP). Details are given about oxide microsphere synthesis and particularly about loading operation and heat treatments. The fabrication of ceramic pellets is also described and discussed. Results showed that this process allows the preparation of either dense or porous pellets by mixing U{sub 3}O{sub 8} and UO{sub 2}-like microspheres before pressing and sintering.

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

    International Nuclear Information System (INIS)

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

  19. Functionally Graded Materials using Plasma Spray with Nano Structured Ceramic

    International Nuclear Information System (INIS)

    In this paper, nano structured FGM was fabricated using DC plasma spray technique. Nano structured and micro structured powder were used as the feeding powder with steel substrate. The spray parameters was optimized and characterisation of nano-ceramic FGM and micro-ceramic FGM were done using bending test and micro-hardness test. Experimental results have shown that the nano-structured FGM exhibit 20% improvement flexure strength and 10% in hardness. A comparison was made between sintered micro ceramic tile and nano ceramic FGM using simple drop test method.

  20. Chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    Uranium dioxide is used as a nuclear-reactor fuel. In order to be suitable for this purpose, the material must meet certain criteria for uranium content, stoichiometry, isotopic composition, impurity content. The following analytical procedures, which are described in detail, are designed to show whether or not a given material meets specifications: uranium by ferrous sulfate reduction in phosphoric acid and dichromate titration method; uranium and oxygen uranium atomic ratio by the ignition (gravimetric) impurity correction method; oxygen to uranium atomic ratios by the polarographic method; carbon (total) by direct combustion-thermal conductivity method; total chlorine and fluorine by pyrohydrolysis ion-selective electrode method; moisture by the coulometric, electrolytic moisture analyzer method; nitrogen by the Kjeldahl method; total sulfur by distillation-spectrophotometric method; isotopic uranium composition by multiple-filament surface-ionization mass spectrometric method; spectrochemical determination of trace elements in high-purity uranium dioxide; volatile fluoride impurities by spectrochemical method using the rotating-disk spark technique; spectrochemical determination of silver by gallium oxide carrier D-C arc technique; rare earths by copper spark-spectrochemical method; impurity elements by a spark-source mass spectrographic method; surface area by nitrogen absorption method; total gas in reactor-grade uranium dioxide pellets; thorium and rare earth elements by spectroscopy; hydrogen by inert gas fusion; and uranium isotopic analysis by mass spectrometry. (JMT)

  1. Bioleaching of low-grade uranium ore using Acidithiobacillus ferrooxidans

    OpenAIRE

    Pal, S; Pradhan, D.; T Das; Sukla, L. B.; Chaudhury, G. Roy

    2010-01-01

    Bioleaching of uranium was carried out with Turamdih ore sample procured from Uranium Corporation of India Limited, Jaduguda. The bacterial strain that was used in the leaching experiments was isolated from the Jaduguda mine water sample. Efficiency of bioleaching was studied by varying parameters like pulp density and initial ferrous concentration as source of energy. It is observed that the efficiency of bioleaching was 49% at 10% pulp density (w/v) and initial pH 2.0. Addition of external ...

  2. Interaction phenomena between ceramic coatings and liquid uranium alloys

    International Nuclear Information System (INIS)

    Owing to the high chemical reactivity of molten uranium alloys, the use of traditional graphite crucibles for casting fuel slugs for a sodium-cooled fast reactor (SFR) is problematic. Moreover, rare earth (RE) elements retained in the fuel slugs for an SFR, which are extracted from the spent fuel by pyro-processing, are more reactive than uranium melt. Therefore, in this study, Y2O3 single-layer coatings with thicknesses of approximately 50, 70, and 120 μm and double-layer coatings of TaC/Y2O3 and Y2O3/TaC were plasma-sprayed onto niobium substrates and tested for thermal shock resistance and compatibility against U-10 wt% Zr and U-10 wt% Zr-5 wt% RE melt. The Y2O3 single-layer coating, regardless of coating thickness, and the TaC/Y2O3 double-layer coating showed good contact at the interface between the coating and the niobium substrate, with no deterioration after the thermal cycling test. In the interaction studies, the single- and double-layer coatings showed good compatibility with the U-Zr melt. However, the Y2O3 coatings with thicknesses of approximately 50 and 70 μm showed severe penetration of the U-Zr-RE melt and reacted with the niobium substrate. The single-layer Y2O3 coating with a thickness of 120 μm and the double-layer TaC/Y2O3 coating exhibited the most promising performance among the candidate coatings. (author)

  3. Amenability of low-grade uranium towards column bioleaching by acidithiobacillus ferrooxidans

    International Nuclear Information System (INIS)

    R and D studies were carried out at NML using Acidithiobacillus ferrooxidans (Ac.Tf) in column for the bio-recovery of uranium from the low-grade uranium ore containing 0.024% U3O8 of Turamdih mines, Singhbhum. A recovery of 55.48% uranium was obtained in bio-leaching as against ∼ 44.9% in sterile control in 30 days at 1.7 pH in a column containing 2.5kg ore of particle size mainly in the range 5-1mm. In the large scale column, leaching with 80kg ore of particle size ∼ 0.5cm, uranium bio-recovery was found to be 69.8% in comparison to a recovery of 55% in control set at 1.7 pH in 50 days. The uranium recoveries followed indirect leaching mechanism. (author)

  4. Bioleaching of low-grade uranium ore using Acidithiobacillus ferrooxidans

    International Nuclear Information System (INIS)

    Bioleaching of uranium was carried out with Turamdih ore sample procured from Uranium Corporation of India Limited, Jaduguda. The bacterial strain that was used in the leaching experiments was isolated from the Jaduguda mine water sample. Efficiency of bioleaching was studied by varying parameters like pulp density and initial ferrous concentration as source of energy. It is observed that the efficiency of bioleaching was 49% at 10% pulp density (w/v) and initial pH 2.0. Addition of external has no effect on efficiency of bioleaching showing domination of direct leaching mechanism over indirect. (author)

  5. PHASE ANALYSES OF URANIUM BEARING MINERALS FROM THE HIGH GRADE ORE, NOPAL I, PENA BLANCA, MEXICO

    International Nuclear Information System (INIS)

    The Nopal I uranium deposit is located in the Pena Blanca district, approximately 40 miles north of Chihuahua City, Mexico. The deposit was formed by hydrothermal processes within the fracture zone of welded silicic volcanic tuff. The ages of volcanic formations are between 35 to 44 m.y. and there was secondary silicification of most of the formations. After the formation of at least part of the uranium deposit, the ore body was uplifted above the water table and is presently exposed at the surface. Detailed petrographic characterization, electron microprobe backscatter electron (BSE) imagery, and selected x-ray maps for the samples from Nopal I high-grade ore document different uranium phases in the ore. There are at least two stages of uranium precipitation. A small amount of uraninite is encapsulated in silica. Hexavalent uranium may also have been a primary precipitant. The uranium phases were precipitated along cleavages of feldspars, and along fractures in the tuff. Energy dispersive spectrometer data and x-ray maps suggest that the major uranium phases are uranophane and weeksite. Substitutions of Ca and K occur in both phases, implying that conditions were variable during the mineralization/alteration process, and that compositions of the original minerals have a major influence on later stage alteration. Continued study is needed to fully characterize uranium behavior in these semi-arid to arid conditions

  6. Crystal chemistry of uranium (V) and plutonium (IV) in a titanate ceramic for disposition of surplus fissile material

    Science.gov (United States)

    Fortner, J. A.; Kropf, A. J.; Finch, R. J.; Bakel, A. J.; Hash, M. C.; Chamberlain, D. B.

    2002-07-01

    We report X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectra for the plutonium LIII and uranium LIII edges in titanate pyrochlore ceramic. The titanate ceramics studied are of the type proposed to serve as a matrix for the immobilization of surplus fissile materials. The samples studied contain approximately 10 wt% fissile plutonium and 20 wt% natural uranium, and are representative of material within the planned production envelope. Based upon natural analogue models, it had been previously assumed that both uranium and plutonium would occupy the calcium site in the pyrochlore crystal structure. While the XANES and EXAFS signals from the plutonium LIII are consistent with this substitution into the calcium site within pyrochlore, the uranium XANES is characteristic of pentavalent uranium. Furthermore, the EXAFS signal from the uranium has a distinct oxygen coordination shell at 2.07 Å and a total oxygen coordination of about 6, which is inconsistent with the calcium site. These combined EXAFS and XANES results provide the first evidence of substantial pentavalent uranium in an octahedral site in pyrochlore. This may also explain the copious nucleation of rutile (TiO 2) precipitates commonly observed in these materials as uranium displaces titanium from the octahedral sites.

  7. Standard test method for the determination of uranium by ignition and the oxygen to uranium (O/U) atomic ratio of nuclear grade uranium dioxide powders and pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This test method covers the determination of uranium and the oxygen to uranium atomic ratio in nuclear grade uranium dioxide powder and pellets. 1.2 This test method does not include provisions for preventing criticality accidents or requirements for health and safety. Observance of this test method does not relieve the user of the obligation to be aware of and conform to all international, national, or federal, state and local regulations pertaining to possessing, shipping, processing, or using source or special nuclear material. 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. 1.4 This test method also is applicable to UO3 and U3O8 powder.

  8. Preliminary study on weapon grade uranium utilization in molten salt reactor miniFUJI

    Energy Technology Data Exchange (ETDEWEB)

    Aji, Indarta Kuncoro [Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung (Indonesia); Waris, A., E-mail: awaris@fi.itb.ac.id [Nuclear Physics and Biophysics Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesa No. 10 Bandung 40132 (Indonesia)

    2014-09-30

    Preliminary study on weapon grade uranium utilization in 25MWth and 50MWth of miniFUJI MSR (molten salt reactor) has been carried out. In this study, a very high enriched uranium that we called weapon grade uranium has been employed in UF{sub 4} composition. The {sup 235}U enrichment is 90 - 95 %. The results show that the 25MWth miniFUJI MSR can get its criticality condition for 1.56 %, 1.76%, and 1.96% of UF{sub 4} with {sup 235}U enrichment of at least 93%, 90%, and 90%, respectively. In contrast, the 50 MWth miniFUJI reactor can be critical for 1.96% of UF{sub 4} with {sup 235}U enrichment of at smallest amount 95%. The neutron spectra are almost similar for each power output.

  9. Optimization of operating parameters and rate of uranium bioleaching from a low-grade ore

    International Nuclear Information System (INIS)

    In this study the bioleaching of a low-grade uranium ore containing 480 ppm uranium has been reported. The studies involved extraction of uranium using Acidithiobacillus ferrooxidans derived from the uranium mine samples. The maximum specific growth rate (μmax) and doubling time (td) were obtained 0.08 h-1 and 8.66 h, respectively. Parameters such as Fe2+ concentration, particle size, temperature and pH were optimized. The effect of pulp density (PD) was also studied. Maximum uranium bio-dissolution of 100 ± 5 % was achieved under the conditions of pH 2.0, 5 % PD and 35 deg C in 48 h with the particles of d80 = 100 μm. The optimum concentration of supplementary Fe2+ was dependent to the PD. This value was 0 and 10 g of FeSO4·7H2O/l at the PD of 5 and 15 %, respectively. The effects of time, pH and PD on the bioleaching process were studied using central composite design. New rate equation was improved for the uranium leaching rate. The rate of leaching is controlled with the concentrations of ferric and ferrous ions in solution. This study shows that uranium bioleaching may be an important process for the Saghand U mine at Yazd (Iran). (author)

  10. Photoneutron logging system for direct uranium ore-grade determination

    International Nuclear Information System (INIS)

    A prototype photoneutron probe for direct uranium assay in exploratory boreholes has been built and field tested. An approx. 10-Ci 124Sb gamma-ray source together with a beryllium converter is used to produce neutrons that diffuse into the surrounding formation and cause fissions in any 235U present. The fission neutrons that return to the probe are energy analyzed and counted by a high-pressure helium detector, thus indicating the concentration of uranium. The response of the probe was measured in concrete models at the US Department of Energy (Grand Junction, Colorado) calibration facility and found to be approx. 35 counts/s for an 1% U3O8 concentration in an 11.4-cm-diam water-filled borehole (4.5 in.). The response is linear up to a concentration of at least 0.25% by weight U3O8. Effects resulting from changes in formation density, porosity, and neutron absorber content were also quantified, as well as the tool response as a function of borehole diameter and fluid. A logging vehicle was outfitted, and the photoneutron-based logging system was field tested at an exploration site near Canon City, Colorado. Logging data obtained in several open holes at this site are presented and compared to core chemical analyses and results obtained in the same holes using other logging methods. In about 1 month of field testing, the photoneutron-based uranium exploration system has proved to be simple to use and very reliable. 22 figures, 12 tables

  11. Neutronics Studies of Uranium-bearing Fully Ceramic Micro-encapsulated Fuel for PWRs

    International Nuclear Information System (INIS)

    Our study evaluated the neutronics and some of the fuel cycle characteristics of using uranium-based fully ceramic microencapsulated (FCM) fuel in a pressurized water reactor (PWR). Specific PWR lattice designs with FCM fuel have been developed that are expected to achieve higher specific burnup levels in the fuel while also increasing the tolerance to reactor accidents. The SCALE software system was the primary analysis tool used to model the lattice designs. A parametric study was performed by varying tristructural isotropic particle design features (e.g., kernel diameter, coating layer thicknesses, and packing fraction) to understand the impact on reactivity and resulting operating cycle length. Moreover, to match the lifetime of an 18-month PWR cycle, the FCM particle fuel design required roughly 10% additional fissile material at beginning of life compared with that of a standard uranium dioxide (UO2) rod. Uranium mononitride proved to be a favorable fuel for the fuel kernel due to its higher heavy metal loading density compared with UO2. The FCM fuel designs evaluated maintain acceptable neutronics design features for fuel lifetime, lattice peaking factors, and nonproliferation figure of merit

  12. Preconcentration of low-grade uranium ores with environmentally acceptable tailings, part I

    International Nuclear Information System (INIS)

    The low-grade ore sample used for this investigation originated from Agnew Lake Mines Limited, Espanola, Ontario. It contained about 1% pyrite and 0.057% uranium, mainly as uranothorite with a small amount of brannerite. Both of these minerals occur in the quartz-sericite matrix of a conglomerate. A preconcentration process has been developed to give a high uranium recovery, reject pyrite, radium and thorium from the ore and produce environmentally acceptable tailings. This process applies flotation in combination with high intensity magnetic separation and gravity concentration

  13. Interface Oscillation in the Side-by-Side (SBS) Tape Casting of Functionally Graded Ceramics (FGCs)

    DEFF Research Database (Denmark)

    Jabbari, Masoud; Bulatova, Regina; Hattel, Jesper Henri;

    2012-01-01

    slurries. The rheological behavior of the slurries are extracted from experiments and used in the ANSYS FLUENT commercial code to develop a fluid flow model for the non-Newtonian ceramic slurries and evaluate the interface oscillation between the stripes in SBS tape casting. The Numerical results show......Room temperature magnetic refrigeration is a new highly efficient and environmentally protective technology. Although it has not been maturely developed, it shows great applicable prosperity and seems to be a potential substitute for the traditional vapor compression technology. Tape Casting is a...... common process in producing multilayer ceramics, which now is used for producing side-by-side (SBS) functionally graded ceramics (FGCs). These FGCs are mostly used in the magnetic refrigeration sectors due to the varying composition of the magnetocaloric materials so that the magnetic transition...

  14. A drop-on-demand ink-jet printer for combinatorial libraries and functionally graded ceramics.

    Science.gov (United States)

    Mohebi, Mohammad Masoud; Evans, Julian R G

    2002-01-01

    A printer has been designed and built for the preparation of combinatorial libraries of ceramics and for solid freeforming of functionally graded ceramics with three-dimensionally programmable spatial variation in composition. Several ceramic suspensions (as inks) can be subjected to micromixing behind the nozzle and printed at precise positions. Both mixing and positioning are computer-controlled. The machine consists of an XY table to control the geometry, a set of electromagnetic valves that manage the mixing, a combined electromagnetic valve and sapphire nozzle that form the print head, and a computer that controls the whole system. The mixing valves can eject as little as 1 mg/s ink into the mixing chamber. The printer has been controlled, run, calibrated and tested; the composition and geometry of printed mixtures can be controlled precisely. This method for the controlled mixing of powders facilitates the advance of combinatorial methods within the materials sciences.

  15. Spectrophotometric study of bio-sorption of uranium on glass grade spodumene shell powder

    International Nuclear Information System (INIS)

    Separation of uranium found in iron ore leachates was done by extraction chromatography using glass grade spodumene shellpowder (GSS) in nitric acid medium and analyzed spectrophotometrically. The influences of metal ion concentration, pH and adsorption capacity of biomass were investigated. Biosorption is a potential method of separation of heavy and trace metals from waste water and effluents from various sources. The adsorption capacities of biomass were investigated by batch experiments and column experiments. In the present study, glass grade spodumene shell powder (GSS) in acidic medium is being used as a biosorbent

  16. Titanate ceramics for immobilisation of uranium-rich radioactive wastes arising from 99Mo production

    Science.gov (United States)

    Carter, M. L.; Li, H.; Zhang, Y.; Vance, E. R.; Mitchell, D. R. G.

    2009-02-01

    Uranium-rich liquid wastes arising from UO 2 targets which have been neutron-irradiated to generate medical radioisotopes such as 99mTc require immobilisation. A pyrochlore-rich hot isostatically pressed titanate ceramic can accommodate at least 40 wt% of such waste expressed on an oxide basis. In this paper, the baseline waste form composition (containing 40 wt% UO 2) was adjusted in two ways: (a) varying the UO 2 loading with constant precursor oxide materials, (b) varying the precursor composition with constant waste loading of UO 2. This resulted in the samples having a similar phase assemblage but the amounts of each phase varied. The oxidation states of U in selected samples were determined using diffuse reflection spectroscopy (DRS) and electron energy loss spectroscopy (EELS). Leaching studies showed that there was no significant difference in the normalised elemental release rates and the normalised release rates are comparable with those from synroc-C. This demonstrates that waste forms based on titanate ceramics are robust and flexible for the immobilisation of U-rich waste streams from radioisotope processing.

  17. Neutronics studies of uranium-based fully ceramic micro-encapsulated fuel for PWRs

    International Nuclear Information System (INIS)

    This study evaluates the core neutronics and fuel cycle characteristics using uranium-based fully ceramic micro-encapsulated (FCM) fuel in a pressurized water reactor (PWR). Specific PWR assembly designs with FCM fuel have been developed, which by virtue of their TRISO particle-based elements are expected to achieve higher fuel burnups while also increasing the tolerance to fuel failures. The SCALE 6.1 code package, developed and maintained at ORNL, was the primary software used to model the assembly designs. Analysis was performed using the SCALE double-heterogeneous (DH) fuel modeling capabilities; however, the Reactivity-Equivalent Physical Transformation (RPT) method was used for lattice calculations due to the long run times associated with the SCALE DH capability. In order to understand the impact on reactivity and reactor operating cycle length, a parametric study was performed by varying TRISO particle design features, such as kernel diameter, coating layer thicknesses, and packing fraction. Also, other features such as the selection of matrix material (SiC, zirconium) and fuel rod dimensions were studied. After evaluating different uranium-based fuels, the higher compound density of uranium mononitride (UN) proved to be favorable, as the parametric studies showed that the FCM particle fuel design will need roughly 12% additional fissile material in comparison to that of a standard UO2 rod in order to match the lifetime of an 18-month PWR cycle. Neutronically, the FCM fuel designs evaluated maintain acceptable design features in the areas of fuel lifetime and temperature coefficients of reactivity, as well as pin cell and assembly peaking factors. (authors)

  18. Assessing alternative strategies for the disposition of weapons-grade uranium and plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Chow, B.G.

    1995-12-31

    Highly-enriched uranium (HEU) from dismantled nuclear weapons and military inventory can be blended down into proliferation-resistant low-enriched uranium and used economically as fuel in current nuclear reactors. However, the US can no longer expect the agreement to purchase and resell the uranium blended down from 500 metric tons of Russia`s HEU to be budget neutral. The authors recommend that other countries participate in the repurchase of blended-down uranium from the US and that a multilateral offer to Russia, which acts on behalf of all four former Soviet nuclear republics, be made for the purchase of the blended-down uranium from Russia`s remaining HEU. Since spent fuel in temporary storage worldwide contains enough plutonium to fuel breeders on any realistic buildup schedule in the event that breeders are needed, there is no need to save the weapons-grade plutonium for the future. This paper compares the costs of burning it in existing light water reactors, storing it indefinitely, and burying it after 20 years of storage. They found that the present-valued cost is about $1 to 2 billion in US dollars for all three alternatives. The deciding factor for selection should be an alternative`s proliferation resistance. Prolonged plutonium storage in Russia runs the risk of theft and, if the Russian political scene turns for the worse, the risk of re-use in its nuclear arsenal. The most urgent issue, however, is to determine not the disposition alternative but whether Russia will let its weapons-grade plutonium leave the former Soviet Republics (FSRs). The US should offer to buy and remove such plutonium from the FSRs. If Russia refuses even after the best US efforts, the US should then persuade Russia to burn or bury the plutonium, but not store it indefinitely for future breeder use.

  19. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1999-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets to determine compliance with specifications. 1.2 This test method covers the determination of uranium and the oxygen to uranium atomic ratio in nuclear-grade uranium dioxide powder and pellets. 1.4 This test method covers the determination of chlorine and fluorine in nuclear-grade uranium dioxide. With a 1 to 10-g sample, concentrations of 5 to 200 g/g of chlorine and 1 to 200 μg/g of fluorine are determined without interference. 1.5 This test method covers the determination of moisture in uranium dioxide samples. Detection limits are as low as 10 μg. 1.6 This test method covers the determination of nitride nitrogen in uranium dioxide in the range from 10 to 250 μg. 1.7 This test method covers the spectrographic analysis of nuclear-grade UO2 for the 26 elements in the ranges indicated in Table 2. 1.8 For simultaneous determination of trace ele...

  20. Uranium

    International Nuclear Information System (INIS)

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

  1. NEUTRONICS STUDIES OF URANIUM-BASED FULLY CERAMIC MICRO-ENCAPSULATED FUEL FOR PWRs

    Energy Technology Data Exchange (ETDEWEB)

    George, Nathan M [ORNL; Maldonado, G Ivan [ORNL; Terrani, Kurt A [ORNL; Gehin, Jess C [ORNL; Godfrey, Andrew T [ORNL

    2012-01-01

    This study evaluates the core neutronics and fuel cycle characteristics that result from employing uranium-based fully ceramic micro-encapsulated (FCM) fuel in a pressurized water reactor (PWR). Specific PWR bundle designs with FCM fuel have been developed, which by virtue of their TRISO particle based elements, are expected to safely reach higher fuel burnups while also increasing the tolerance to fuel failures. The SCALE 6.1 code package, developed and maintained at ORNL, was the primary software employed to model these designs. Analysis was performed using the SCALE double-heterogeneous (DH) fuel modeling capabilities. For cases evaluated with the NESTLE full-core three-dimensional nodal simulator, because the feature to perform DH lattice physics branches with the SCALE/TRITON sequence is not yet available, the Reactivity-Equivalent Physical Transformation (RPT) method was used as workaround to support the full core analyses. As part of the fuel assembly design evaluations, fresh feed lattices were modeled to analyze the within-assembly pin power peaking. Also, a color-set array of assemblies was constructed to evaluate power peaking and power sharing between a once-burned and a fresh feed assembly. In addition, a parametric study was performed by varying the various TRISO particle design features; such as kernel diameter, coating layer thicknesses, and packing fractions. Also, other features such as the selection of matrix material (SiC, Zirconium) and fuel rod dimensions were perturbed. After evaluating different uranium-based fuels, the higher physical density of uranium mononitride (UN) proved to be favorable, as the parametric studies showed that the FCM particle fuel design will need roughly 12% additional fissile material in comparison to that of a standard UO2 rod in order to match the lifetime of an 18-month PWR cycle. Neutronically, the FCM fuel designs evaluated maintain acceptable design features in the areas of fuel lifetime, temperature

  2. Influence of Inclusion Shape on Thermoelasto-Plastic Optimun Design of Ceramic Metal Functionally Graded Materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A nonlinear finite element method is applied to observe how inclusion shape influence the thermal response of a ceramic-metal functionally graded material (FGM).The elastic and plastic behaviors of the layers which are two-phase isotropic composites consisting of randomly oriented elastic spheroidal inclusions and a ductile matrix are predicted by a mean field method.The prediction results show that inclusion shape has remarkable influence on the overall behavior of the composite.The consequences of the thermal response analysis of the FGM are that the response is dependent on inclusion shape and its composition profile cooperatively and that the plastic behavior of each layer should be taken into account in optimum design of a ceramic-metal FGM.

  3. Development of a pneumatic transport system for bulk transfer of metal grade uranium oxide powder

    International Nuclear Information System (INIS)

    Uranium oxide powder is a commonly handled ceramic powder in nuclear industries. Design of the powder transfer system is an important aspect because of some of its typical characteristics. Pneumatic transport system has been widely used in transferring powder from one place to another. A pneumatic transport system using vacuum has been presented in the paper. This is used for bulk transfer of UO3 powder. The system consists of a cyclone separator and filter cloth at the top of the cyclone separator. The pneumatic transfer system provides high efficiency with sustainable performance and it is a compact, robust, handy and moveable unit. No degradation of the powder quality has been observed during transfer. The system provides highly efficient, easy and safe transfer of radioactive powder, better working environment for the operator. (author)

  4. Proliferation dangers associated with nuclear medicine: getting weapons-grade uranium out of radiopharmaceutical production.

    Science.gov (United States)

    Williams, Bill; Ruff, Tilman A

    2007-01-01

    Abolishing the threat of nuclear war requires the outlawing of nuclear weapons and dismantling current nuclear weapon stockpiles, but also depends on eliminating access to fissile material (nuclear weapon fuel). The near-universal use of weapons-grade, highly enriched uranium (HEU) to produce radiopharmaceuticals is a significant proliferation hazard. Health professionals have a strategic opportunity and obligation to progress the elimination of medically-related commerce in HEU, closing one of the most vulnerable pathways to the much-feared 'terrorist bomb'.

  5. Standard specification for uranium oxides with a 235U content of less than 5 % for dissolution prior to conversion to nuclear-grade uranium dioxide

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This specification covers uranium oxides, including processed byproducts or scrap material (powder, pellets, or pieces), that are intended for dissolution into uranyl nitrate solution meeting the requirements of Specification C788 prior to conversion into nuclear grade UO2 powder with a 235U content of less than 5 %. This specification defines the impurity and uranium isotope limits for such urania powders that are to be dissolved prior to processing to nuclear grade UO2 as defined in Specification C753. 1.2 This specification provides the nuclear industry with a general standard for such uranium oxide powders. It recognizes the diversity of conversion processes and the processes to which such powders are subsequently to be subjected (for instance, by solvent extraction). It is therefore anticipated that it may be necessary to include supplementary specification limits by agreement between the buyer and seller. 1.3 The scope of this specification does not comprehensively cover all provisions for prevent...

  6. Solid phase separation and ICP-OES/ICP-MS determination of rare earth impurities in nuclear grade uranium oxide

    International Nuclear Information System (INIS)

    A simple, effective and low cost solid phase extraction procedure was standardized for the trace and ultra-trace level determination of rare earth impurities, such as, Ce, Dy, Sm, Gd, Eu, Er etc. which act as neutron poisons, in nuclear grade uranium oxide (U3O8 > 99.9% by weight). The method involves selective separation of these elements as their fluorides with the help of activated charcoal from major uranium matrix followed by determination by ICP-MS and high resolution ICP-OES. The residual uranium content of the solution was <10 μg/mL. The recovery of REEs ranges from 85 to 105%. The method was validated with nuclear grade uranium oxide standards CRM-I to CRM-V (BARC, Mumbai, India) in addition to some synthetic standards. The RSD of the method was ±12% (n = 3). (author)

  7. Ballistic Studies on TiB2-Ti Functionally Graded Armor Ceramics

    Directory of Open Access Journals (Sweden)

    Neha Gupta

    2012-11-01

    Full Text Available The objective of this paper is to discuss the results of the ballistic testing of the spark plasma sintered TiB2-Ti based functionally graded materials (FGMs with an aim to assess their performance in defeating small-calibre armor piercing projectiles. We studied the efficacy of FGM design and compared its ballistic properties with those of TiB2-based composites as well as other competing ceramic armors. The ballistic properties are critically analyzed in terms of depth of penetration, ballistic efficiency, fractographs of fractured surfaces as well as quantification of the shattered ceramic fragments. It was found that all the investigated ceramic compositions exhibit ballistic efficiency (η of 5.1 -5.9. We also found that by increasing the thickness of FGM from 5mm to 7.8 mm, the ballistic property of the composite degraded. On comparing the results with available armor systems, it has been concluded that TiB2 based composites show better ballistic properties except B4C. SEM analysis of the fragments showed that the FGM fractured by mixed mode of failure.Defence Science Journal, 2012, 62(6, pp.382-389, DOI:http://dx.doi.org/10.14429/dsj.62.2666

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

    International Nuclear Information System (INIS)

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

  9. PHASE ANALYSES OF URANIUM-BEARING MINERALS FROM THE HIGH GRADE ORE, NOPAL I, PENA BLANCA, MEXICO

    Energy Technology Data Exchange (ETDEWEB)

    M. Ren; P. Goodell; A. Kelts; E.Y. Anthony; M. Fayek; C. Fan; C. Beshears

    2005-07-11

    The Nopal I uranium deposit is located in the Pena Blanca district, approximately 40 miles north of Chihuahua City, Mexico. The deposit was formed by hydrothermal processes within the fracture zone of welded silicic volcanic tuff. The ages of volcanic formations are between 35 to 44 m.y. and there was secondary silicification of most of the formations. After the formation of at least part of the uranium deposit, the ore body was uplifted above the water table and is presently exposed at the surface. Detailed petrographic characterization, electron microprobe backscatter electron (BSE) imagery, and selected x-ray maps for the samples from Nopal I high-grade ore document different uranium phases in the ore. There are at least two stages of uranium precipitation. A small amount of uraninite is encapsulated in silica. Hexavalent uranium may also have been a primary precipitant. The uranium phases were precipitated along cleavages of feldspars, and along fractures in the tuff. Energy dispersive spectrometer data and x-ray maps suggest that the major uranium phases are uranophane and weeksite. Substitutions of Ca and K occur in both phases, implying that conditions were variable during the mineralization/alteration process, and that compositions of the original minerals have a major influence on later stage alteration. Continued study is needed to fully characterize uranium behavior in these semi-arid to arid conditions.

  10. Uranium

    International Nuclear Information System (INIS)

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

  11. Uranium

    International Nuclear Information System (INIS)

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

  12. Uranium

    International Nuclear Information System (INIS)

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

  13. Analysis of Thermal Buckling of Ceramic-Metal Functionally Graded Plates Using Refined Third Order Shear Deformation Theory

    Directory of Open Access Journals (Sweden)

    S. S. Daimi

    2014-08-01

    Full Text Available Functionally graded materials (FGMs are microscopically inhomogeneous spatial composite materials, typically composed of a ceramic-metal or ceramic-polymer pair of materials. Therefore, it is important to investigate the behaviors of engineering structures such as beams and plates made from FGMs when they are subjected to thermal loads for appropriate design. Therefore, using an improved third order shear deformation theory (TSDT based on more rigorous kinetics of displacements to predict the behaviors of functionally graded plates is expected to be more suitable than using other theories. In this paper, the improved TSDT is used to investigate thermal buckling of functionally graded plates. Temperature dependent material property solutions are adopted to investigate thermal buckling results of functionally graded plates. To obtain the solutions, the Ritz method using polynomial and trigonometric functions for defining admissible displacements and rotations is applied to solve the governing equations.

  14. Net shape manufacturing of ceramic micro parts with tailored graded layers

    International Nuclear Information System (INIS)

    Presented in this paper is a novel net shape manufacturing technology for making three-dimensional micro parts with functionally graded layers. Alumina/zirconia micro parts with either core–shell or top–bottom functionally graded material (FGM) profiles have been successfully fabricated by altering both the surface characteristics of polydimethylsiloxane (PDMS) micro moulds and ceramic suspensions composition. PDMS surface modifications were performed to achieve moulds with hydrophilic surfaces, which were used to form core/shell FGM green layers. On the other hand, moulds with hydrophobic surfaces were used to form top–bottom green layers. Cracks have been found between consecutive layers in both the green and sintered micro parts. It was found that, at dispersant concentration of about 9.0 mg g−1, the differences in the drying shrinkage between layers is less than 0.5%. In addition, layers of composition of 100% Al2O3–0% YSZ, 20% Al2O3–80% YSZ and 40% Al2O3–60% YSZ were found to produce less shrinkage difference during sintering. After optimization of both green and sintering layers, crack free core/shell and top–bottom alumina/zirconia FGM micro parts were successfully obtained. The proposed process enables the production of micro patterns tailored with functionally graded microstructures to locally enhance properties and performance. (paper)

  15. Net shape manufacturing of ceramic micro parts with tailored graded layers

    Science.gov (United States)

    Hassanin, H.; Jiang, K.

    2014-01-01

    Presented in this paper is a novel net shape manufacturing technology for making three-dimensional micro parts with functionally graded layers. Alumina/zirconia micro parts with either core-shell or top-bottom functionally graded material (FGM) profiles have been successfully fabricated by altering both the surface characteristics of polydimethylsiloxane (PDMS) micro moulds and ceramic suspensions composition. PDMS surface modifications were performed to achieve moulds with hydrophilic surfaces, which were used to form core/shell FGM green layers. On the other hand, moulds with hydrophobic surfaces were used to form top-bottom green layers. Cracks have been found between consecutive layers in both the green and sintered micro parts. It was found that, at dispersant concentration of about 9.0 mg g-1, the differences in the drying shrinkage between layers is less than 0.5%. In addition, layers of composition of 100% Al2O3-0% YSZ, 20% Al2O3-80% YSZ and 40% Al2O3-60% YSZ were found to produce less shrinkage difference during sintering. After optimization of both green and sintering layers, crack free core/shell and top-bottom alumina/zirconia FGM micro parts were successfully obtained. The proposed process enables the production of micro patterns tailored with functionally graded microstructures to locally enhance properties and performance.

  16. Studio in Sculpture, Ceramics, Jewelry. Advanced Elective Courses in Art for Grades 10, 11, or 12: Volume 2.

    Science.gov (United States)

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    This is the second volume in a series that includes the syllabi for the advanced elective courses in the New York state art program for grades 10, 11, and 12. The first volume is described in ED 100 747. The guide consists of the following three sections: (1) Studio in Ceramics, (2) Studio in Sculpture, and (3) Studio in Jewelry and…

  17. Processing of Low-Grade Uranium Ores. Proceedings of a Panel

    International Nuclear Information System (INIS)

    The 22 specialists from 15 countries and one international organization who attended the meeting were asked to give an appraisal of the current situation with regard to the processing of low-grade uranium ores and make recommendations for a possible IAEA programme of activities. This publication covers the work of the panel. Contents: Status reports (13 reports); Technical reports (13 reports); Summaries of discussions; Recommendations of the panel. Each report is in its original language (16 English, 4 French, 2 Russian and 4 Spanish) and each technical report is preceded by an abstract in English and one in the original language if this is not English. The summaries of discussions and the panel recommendations are in English. (author)

  18. Estimation of trace impurities in reactor-grade uranium using ICP-AES.

    Science.gov (United States)

    Malhotra, R K; Satyanarayana, K

    1999-10-01

    Estimation of impurities in reactor grade uranium is important from the point of view of neutron economy. For chemical separation, ion exchange and solvent extraction techniques have been employed although the latter is generally preferred. Amongst various extractants TBP (tri-n-butyl phosphate), TBP-TOPO (tri-n-octyl phosphine oxide), or TOPO only (in CCl(4), xylene, dodecane) is most often used. New reagents like Cyanex-923 (mixture of 4 tri-alkyl phosphine oxides)/TEHP (tri-ethylhexyl phosphoric acid) are also being used. This communication reports chemical separation of uranium by precipitation using 1,2-diaminocyclohexane NNN'N'-tetra acetic acid (CyDTA)/ammonium hydroxide in presence of 1,10-phenanthroline and estimation of impurities in the filtrate by ICP-AES. Quantitative separation of U, a high spectral interferent in plasma and recovery of impurities have been achieved. Recovery of Cd has been improved by using 1,10-phenanthroline. The method is accurate and precise, offering a relative standard deviation ranging from less than 4% (3.8% for Eu at the 10mug g(-1) level) to 12.9% (for Ce at the 2.5 mug g(-1) level) for all the elements studied.

  19. Thermal shock resistance behavior of a functionally graded ceramic: Effects of finite cooling rate

    Directory of Open Access Journals (Sweden)

    Zhihe Jin

    2014-01-01

    Full Text Available This work presents a semi-analytical model to explore the effects of cooling rate on the thermal shock resistance behavior of a functionally graded ceramic (FGC plate with a periodic array of edge cracks. The FGC is assumed to be a thermally heterogeneous material with constant elastic modulus and Poisson's ratio. The cooling rate applied at the FGC surface is modeled using a linear ramp function. An integral equation method and a closed form asymptotic temperature solution are employed to compute the thermal stress intensity factor (TSIF. The thermal shock residual strength and critical thermal shock of the FGC plate are obtained using the SIF criterion. Thermal shock simulations for an Al2O3/Si3N4 FGC indicate that a finite cooling rate leads to a significantly higher critical thermal shock than that under the sudden cooling condition. The residual strength, however, is relatively insensitive to the cooling rate.

  20. Treatment of an isolated high-grade, low-tonnage uranium orebody

    International Nuclear Information System (INIS)

    A completely integrated process leading to a commercial-grade uranium concentrate has been developed for the El Nopal orebody which contains 115000t of ore with an average grade of 0.283%, equivalent to 325t of U3O8. The process consists of crushing (from -12 in to -1.5in), heap leaching with recirculation, a special type of countercurrent washing (also in the heap), solvent extraction to give an exceptionally high uranium concentration, re-extraction, precipitation with ammonium hydroxide, filtration and calcining. The main factors that influence heap leaching are analysed in detail: heap geometry, crushed ore size distribution, base design and construction, method of heaping, acid feeding method, flow of liquors through the heap and washing procedures. Leaching efficiencies range from 80 to 85% and washing efficiencies from 96 to almost 100% with an overall extraction efficiency of 77 to 85%. Acid consumption is usually less than 25kg/t of ore. The leaching and washing processes described are designed to use an overall solid-to-liquid ratio of about 3:1 thus producing very concentrated liquors with a U3O8 content of about 7g/l. These liquors are filtered and fed directly to a solvent extraction system using Alamine 336 (tri-capryl amine) and isodecanol in kerosene. The high feed concentration makes it possible to use a high concentration of amine. The organic solvent contains 120g/l of Alamine and 98g/l of isodecanol. Re-extraction can be with a saline solution containing 100g/lNH4Cl and 250g/l(NH4)SO4. The strong liquor obtained from re-extraction contains 70-75g/lU3O8. The remaining steps of precipitation, filtration and calcining can then follow general practice and lead to a product which meets currently accepted commercial specifications. As an alternative, nitrate re-extraction has been shown to produce a solution of about 70g/l which will feed directly to tributyl phosphate (TBP) refining without the necessity of ever producing a concentrate. (author)

  1. Manufacturing process scale-up of optical grade transparent spinel ceramic at ArmorLine Corporation

    Science.gov (United States)

    Spilman, Joseph; Voyles, John; Nick, Joseph; Shaffer, Lawrence

    2013-06-01

    While transparent Spinel ceramic's mechanical and optical characteristics are ideal for many Ultraviolet (UV), visible, Short-Wave Infrared (SWIR), Mid-Wave Infrared (MWIR), and multispectral sensor window applications, commercial adoption of the material has been hampered because the material has historically been available in relatively small sizes (one square foot per window or less), low volumes, unreliable supply, and with unreliable quality. Recent efforts, most notably by Technology Assessment and Transfer (TA and T), have scaled-up manufacturing processes and demonstrated the capability to produce larger windows on the order of two square feet, but with limited output not suitable for production type programs. ArmorLine Corporation licensed the hot-pressed Spinel manufacturing know-how of TA and T in 2009 with the goal of building the world's first dedicated full-scale Spinel production facility, enabling the supply of a reliable and sufficient volume of large Transparent Armor and Optical Grade Spinel plates. With over $20 million of private investment by J.F. Lehman and Company, ArmorLine has installed and commissioned the largest vacuum hot press in the world, the largest high-temperature/high-pressure hot isostatic press in the world, and supporting manufacturing processes within 75,000 square feet of manufacturing space. ArmorLine's equipment is capable of producing window blanks as large as 50" x 30" and the facility is capable of producing substantial volumes of material with its Lean configuration and 24/7 operation. Initial production capability was achieved in 2012. ArmorLine will discuss the challenges that were encountered during scale-up of the manufacturing processes, ArmorLine Optical Grade Spinel optical performance, and provide an overview of the facility and its capabilities.

  2. Standard test method for determination of impurities in nuclear grade uranium compounds by inductively coupled plasma mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of 67 elements in uranium dioxide samples and nuclear grade uranium compounds and solutions without matrix separation by inductively coupled plasma mass spectrometry (ICP-MS). The elements are listed in Table 1. These elements can also be determined in uranyl nitrate hexahydrate (UNH), uranium hexafluoride (UF6), triuranium octoxide (U3O8) and uranium trioxide (UO3) if these compounds are treated and converted to the same uranium concentration solution. 1.2 The elements boron, sodium, silicon, phosphorus, potassium, calcium and iron can be determined using different techniques. The analyst's instrumentation will determine which procedure is chosen for the analysis. 1.3 The test method for technetium-99 is given in Annex A1. 1.4 The values stated in SI units are to be regarded as standard. 1.5 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 ...

  3. Glass-Ceramic Waste Forms for Uranium and Plutonium Residues Wastes - 13164

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Martin W.A.; Moricca, Sam A.; Zhang, Yingjie; Day, R. Arthur; Begg, Bruce D. [Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234 (Australia); Scales, Charlie R.; Maddrell, Ewan R. [National Nuclear Laboratory, Sellafield, Seascale, Cumbria, UK, CA20 1PG (United Kingdom); Hobbs, Jeff [Sellafield Limited, Sellafield, Seascale, Cumbria, UK, CA20 1PG (United Kingdom)

    2013-07-01

    A program of work has been undertaken to treat plutonium-residues wastes at Sellafield. These have arisen from past fuel development work and are highly variable in both physical and chemical composition. The principal radiological elements present are U and Pu, with small amounts of Th. The waste packages contain Pu in amounts that are too low to be economically recycled as fuel and too high to be disposed of as lower level Pu contaminated material. NNL and ANSTO have developed full-ceramic and glass-ceramic waste forms in which hot-isostatic pressing is used as the consolidation step to safely immobilize the waste into a form suitable for long-term disposition. We discuss development work on the glass-ceramic developed for impure waste streams, in particular the effect of variations in the waste feed chemistry glass-ceramic. The waste chemistry was categorized into actinides, impurity cations, glass formers and anions. Variations of the relative amounts of these on the properties and chemistry of the waste form were investigated and the waste form was found to be largely unaffected by these changes. This work mainly discusses the initial trials with Th and U. Later trials with larger variations and work with Pu-doped samples further confirmed the flexibility of the glass-ceramic. (authors)

  4. Surface Functionalized Nanostructured Ceramic Sorbents for the Effective Collection and Recovery of Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Chouyyok, Wilaiwan; Pittman, Jonathan W.; Warner, Marvin G.; Nell, Kara M.; Clubb, Donald C.; Gill, Gary A.; Addleman, Raymond S.

    2016-05-02

    The ability to collect uranium from seawater offers the potential for a nearly limitless fuel supply for nuclear energy. We evaluated the use of functionalized nanostructured sorbents for the collection and recovery of uranium from seawater. Extraction of trace minerals from seawater and brines is challenging due to the high ionic strength of seawater, low mineral concentrations, and fouling of surfaces over time. We demonstrate that rationally assembled sorbent materials that integrate high affinity surface chemistry and high surface area nanostructures into an application relevant micro/macro structure enables collection performance that far exceeds typical sorbent materials. High surface area nanostructured silica with surface chemistries composed of phosphonic acid, phosphonates, 3,4 hydroxypyridinone, and EDTA showed superior performance for uranium collection. A few phosphorous-based commercial resins, specifically Diphonix and Ln Resin, also performed well. We demonstrate an effective and environmentally benign method of stripping the uranium from the high affinity sorbents using inexpensive nontoxic carbonate solutions. The cyclic use of preferred sorbents and acidic reconditioning of materials was shown to improve performance. Composite thin films composed of the nanostructured sorbents and a porous polymer binder are shown to have excellent kinetics and good capacity while providing an effective processing configuration for trace mineral recovery from solutions. Initial work using the composite thin films shows significant improvements in processing capacity over the previously reported sorbent materials.

  5. Surface functionalized nanostructured ceramic sorbents for the effective collection and recovery of uranium from seawater.

    Science.gov (United States)

    Chouyyok, Wilaiwan; Pittman, Jonathan W; Warner, Marvin G; Nell, Kara M; Clubb, Donald C; Gill, Gary A; Addleman, R Shane

    2016-07-28

    The ability to collect uranium from seawater offers the potential for a nearly limitless fuel supply for nuclear energy. We evaluated the use of functionalized nanostructured sorbents for the collection and recovery of uranium from seawater. Extraction of trace minerals from seawater and brines is challenging due to the high ionic strength of seawater, low mineral concentrations, and fouling of surfaces over time. We demonstrate that rationally assembled sorbent materials that integrate high affinity surface chemistry and high surface area nanostructures into an application relevant micro/macro structure enables collection performance that far exceeds typical sorbent materials. High surface area nanostructured silica with surface chemistries composed of phosphonic acid, phosphonates, 3,4 hydroxypyridinone, and EDTA showed superior performance for uranium collection. A few phosphorous-based commercial resins, specifically Diphonix and Ln Resin, also performed well. We demonstrate an effective and environmentally benign method of stripping the uranium from the high affinity sorbents using inexpensive nontoxic carbonate solutions. The cyclic use of preferred sorbents and acidic reconditioning of materials was shown to improve performance. Composite thin films composed of the nanostructured sorbents and a porous polymer binder are shown to have excellent kinetics and good capacity while providing an effective processing configuration for trace mineral recovery from solutions. Initial work using the composite thin films shows significant improvements in processing capacity over the previously reported sorbent materials. PMID:27184739

  6. A process efficiency assessment of serum protein removal from milk using ceramic graded permeability microfiltration membrane.

    Science.gov (United States)

    Tremblay-Marchand, D; Doyen, A; Britten, M; Pouliot, Y

    2016-07-01

    Microfiltration (MF) is a well-known process that can be used in the dairy industry to separate caseins from serum proteins (SP) in skim milk using membranes with a pore diameter of 0.1μm. Graded permeability ceramic membranes have been studied widely as means of improving milk fractionation by overcoming problems encountered with other MF membranes. The ideal operating parameters for process efficiency in terms of membrane selectivity, permeate flux, casein loss, SP transmission, energy consumption, and dilution with water remain to be determined for this membrane. Our objective was to evaluate the effects of transmembrane pressure (TMP), volumetric concentration factor (VCF), and diafiltration on overall process efficiency. Skim milk was processed using a pilot-scale MF system equipped with 0.72-m(2) graded permeability membranes with a pore size of 0.1μm. In the first experiment, in full recycle mode, TMP was set at 124, 152, 179, or 207 kPa by adjusting the permeate pressure at the outlet. Whereas TMP had no significant effect on permeate and retentate composition, 152 kPa was found to be optimal for SP removal during concentration and concentration or diafiltration experiments. When VCF was increased to 3×, SP rejection coefficient increased along with energy consumption and total casein loss, whereas SP removal rate decreased. Diafiltering twice allowed an increase in total SP removal but resulted in a substantial increase in energy consumption and casein loss. It also reduced the SP removal rate by diluting permeate. The membrane surface area required for producing cheese milk by blending whole milk, cream, and MF retentate (at different VCF) was estimated for different cheese milk casein concentrations. For a given casein concentration, the same quantity of permeate and SP would be produced, but less membrane surface area would be needed at a lower retentate VCF. Microfiltration has great potential as a process of adding value to conventional

  7. Managing proliferation risks from civilian and weapon-grade plutonium and enriched uranium: A comprehensive cut-off convention

    International Nuclear Information System (INIS)

    The problem of weapon-grade fissile materials is closely related to the aim of achieving a nuclear-weapon-free world. Huge amounts of highly enriched uranium have been produced for nuclear weapons. More than 1000 tonnes of plutonium emerged as a by-product of civilian nuclear industry. Separated from spent fuel it is readily usable for nuclear weapons. The worldwide civilian tritium inventory may reach the same size as military stocks about the year 2010. This poses an increasing danger of horizontal nuclear proliferation. Production, stockpiling, trade, processing and uses of weapon-grade materials like Highly enriched uranium, plutonium and tritium promote its geographical spread, enlarge the group of people with the relate know-how and create the danger of diversion of material and the proliferation of knowledge for the purpose of weapons production. Therefore, a fundamental turn away from using weapon-grade materials in scientific and economic applications of nuclear energy is desirable in all countries. Priority should be given to using nuclear fuel cycles which are as proliferation resistant as possible. Without this, the continuation of civil nuclear programs seems to be irresponsible and unjustifiable. The role of the IAEA in export control safeguards related to the above problems is indispensable

  8. Impact Of Low Grade Uranium Ores On The Echo System and the Workers of Phosphate Industry

    International Nuclear Information System (INIS)

    The present study aims to investigate the influence of uranium present in phosphate rocks as an environmental factor in the ccho system and on the workers of Abu-Zaabal Phosphate Company subjected to the inhalation of big quantities of rock phosphate dust during the benefication of the ore and the production of the fertilizers. Besides. extra amount of uranium reach the workers also through two path ways.The first is direct through eating contaminated planted grown in the near by area.The second is indirect through eating animals fed with contaminated plants. The uranium content is estimated in the soil samples at different depths, water (irrigation and drainage), air samples and plant samples (shoot and root) in Berseem from the four directions, urine samples from twenty workers in charge of the processing of phosphate compared to twenty volunteers far from the contaminated area.The results showed an elevated values for phosphorus and uranium in the air, water. soil and plant (Berseem) around Abu Zaabal Factory and extending to about 2 km from all directions. Urine may be considered as a biological indicator medium for the uptake of uranium in uranium miners and the workers in charge of ore processing and can represent the major route of excretion for the absorbed metal. Significant differences were shown between the uranium level in the urine of workers group and the control group

  9. Bioleaching of low grade uranium ore containing pyrite using A. ferrooxidans and A. thiooxidans

    International Nuclear Information System (INIS)

    A process of uranium extraction from ore containing 3.1 % pyrite by bacterial leaching was investigated in shaken flasks during 90 days. The highest uranium recovery amounting to 85.1 % was obtained using binary mixture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans that was exceeding results obtained by traditional acid leaching technique up to 27 %. High uranium recovery was founded to be due to the high degree of pyrite dissolution that can be readily achieved by bacterial leaching (up to 98.0 %). (author)

  10. The Effect Of Ceramic In Combination Of Two Sigmoid Functionally Graded Rotating Disks With Variable Thickness

    DEFF Research Database (Denmark)

    Bayat, M.; Sahari, B. B.; Saleem, M.

    2012-01-01

    In this paper the elastic solutions of a disk composed of FGM – Functionaly Graded Material, is presented.......In this paper the elastic solutions of a disk composed of FGM – Functionaly Graded Material, is presented....

  11. A guide to the lower limit - combination of size and grade - of deposits of interest for uranium resources

    International Nuclear Information System (INIS)

    An attempt has been made to establish a method of classifying in broad terms low-tonnage/low-grade uranium resources in terms of size, recovery grade and gross sales revenue at various price levels. To arrive at a basis for discussion, the following assumptions are made: (i) An overall average U3O8 recovery grade of less than 50 g/t will never constitute a viable proposition; (ii) That no deposit, or cluster of deposits, containing less than 500,000 t ore will constitute a viable deposit; and (iii) Revenue requirements would vary according to the needs of the producer. It is, however, suggested that a gross sales revenue of US $50,000,000 over the life of the mine (10 years) is regarded as an absolute minimum requirement for viability. From these data a family of curves has been constructed using a tonnage/grade combination which gives a gross revenue of US $50,000,000 for various price categories in terms of $/kg U. These curves may then be used to categorize deposits and to ascertain whether they are likely to constitute a viable proposition within the constraints listed above. (author)

  12. The XPS study of the structure of uranium-containing ceramics

    Directory of Open Access Journals (Sweden)

    Teterin Anton Yu.

    2010-01-01

    Full Text Available The samples of the (Ca0.5GdU0.5Zr2O7 and (Ca0.5GdU0.5(ZrTiO7 ceramics with the fluorite and pyrochlore structures used as matrixes for the long-lived high-level radioactive waste disposal were studied with the X-ray photoelectron spectroscopy method. On the basis of the X-ray photoelectron spectroscopy parameters of the outer and core electrons from the binding energy range of 0-1250 eV the oxidation states of the included metal ions were determined, the quantitative elemental and ionic analysis was done, and the orderliness (monophaseness was evaluated. The obtained data agree with the X-ray diffraction and the scanning electron microscopy results.

  13. Bacteriological lixiviation of low-grade uranium ores at low temperatures, by phiobacillus ferrooxidaus

    International Nuclear Information System (INIS)

    Laboratory experiments are described that, using selective and mutagenic agents, allowed the isolation of a strain of thiobacillus ferrooxidams capable of developing at 80C, and keeping its oxidesing characteristics tests showed that the isoled sample is capable of solubilizing 95% of the uranium content in samples with U3O8 content below 1000ppm

  14. Environmental control technology for mining and milling low-grade uranium resources

    International Nuclear Information System (INIS)

    This study examined the type and level of wastes that would be generated in the mining and milling of U3O8 from four potential domestic sources of uranium. The estimated costs of the technology to control these wastes to different degrees of stringency are presented

  15. Radiological safety in mining of low grade uranium ores: Four decades of monitoring and control in Indian mines

    International Nuclear Information System (INIS)

    Full text: Mining of low grade uranium ore involves deployment of large man power in many stopes simultaneously to achieve the production target. The first uranium mine in India commenced commercial operation in 1968 with production from shallower haulage levels. The mine is now operating up to a vertical depth of about 905 meters. Radiation exposure of workers is mainly from external gamma radiation and inhalation of radon progeny. The long lived alpha emitters in the airborne ore dust are relatively small in such mines. While gamma radiation is not amenable to control the radon and its progeny can be effectively reduced by adequate ventilation and a judicious distribution of ventilating air to the working zones and sealing of worked out areas. Workplace monitoring for radiological parameters in the mines commenced right from the beginning of the operations. Initially the effective dose to the workers was evaluated from the area monitoring and occupancy period of workers in different zones. Subsequently, SSNTD and TLD based personal dosimeters were developed and deployed in a phased manner. Average dose to the workers in the early stages was around 10 mSv/y. Ventilation was progressively improved by widening of air passages and increasing the fan capacity. The system itself was modified from the series to a parallel system of ventilation to supply fresh air to each operating haulage level and allow the used air to join the return air stream. The modifications had positive impact and the average doses have shown a downward trend are now around 5 mSv/y. Progressive mechanization of mining operations over the years has resulted in reduction of manpower and consequently in a reduction of the collective dose. Subsequently, three additional underground uranium mines have been opened with low grade uranium ores. Increasing ventilation has resulted in reduction of radon concentration to an average of around 0.3 KBq/m3 EER in Jaduguda mine. The internal and external

  16. Utilization of non-weapons-grade plutonium and highly enriched uranium with breeding of the 233U isotope in the VVER reactors using thorium and heavy water

    Science.gov (United States)

    Marshalkin, V. E.; Povyshev, V. M.

    2015-12-01

    A method for joint utilization of non-weapons-grade plutonium and highly enriched uranium in the thorium-uranium—plutonium oxide fuel of a water-moderated reactor with a varying water composition (D2O, H2O) is proposed. The method is characterized by efficient breeding of the 233U isotope and safe reactor operation and is comparatively simple to implement.

  17. Utilization of non-weapons-grade plutonium and highly enriched uranium with breeding of the 233U isotope in the VVER reactors using thorium and heavy water

    International Nuclear Information System (INIS)

    A method for joint utilization of non-weapons-grade plutonium and highly enriched uranium in the thorium–uranium—plutonium oxide fuel of a water-moderated reactor with a varying water composition (D2O, H2O) is proposed. The method is characterized by efficient breeding of the 233U isotope and safe reactor operation and is comparatively simple to implement

  18. The effect of tape casting operational parameters on the quality of adjacently graded ceramic film

    DEFF Research Database (Denmark)

    Bulatova, Regina; Gudik-Sørensen, Mads; Della Negra, Michela;

    2016-01-01

    For small length tape casting of ceramic slurries varying green film thickness is often a problem. To optimise this, the following parameters were investigated: single blade, double blade, using a pump system and a modelled speed change mode have been analysed. Advantages and limitations of every...... method are described here. The tape casting experiments were built to be generic in order to allow the control of various processing conditions. From these results, the single-blade technique was chosen for a study of side-by-side tape casting. The influence of the geometric parameters of partitioning...

  19. Weapons-grade plutonium dispositioning. Volume 3: A new reactor concept without uranium or thorium for burning weapons-grade plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Ryskamp, J.M.; Schnitzler, B.G.; Fletcher, C.D. [and others

    1993-06-01

    The National Academy of Sciences (NAS) requested that the Idaho National Engineering Laboratory (INEL) examine concepts that focus only on the destruction of 50,000 kg of weapons-grade plutonium. A concept has been developed by the INEL for a low-temperature, low-pressure, low-power density, low-coolant-flow-rate light water reactor that destroys plutonium quickly without using uranium or thorium. This concept is very safe and could be designed, constructed, and operated in a reasonable time frame. This concept does not produce electricity. Not considering other missions frees the design from the paradigms and constraints used by proponents of other dispositioning concepts. The plutonium destruction design goal is most easily achievable with a large, moderate power reactor that operates at a significantly lower thermal power density than is appropriate for reactors with multiple design goals. This volume presents the assumptions and requirements, a reactor concept overview, and a list of recommendations. The appendices contain detailed discussions on plutonium dispositioning, self-protection, fuel types, neutronics, thermal hydraulics, off-site radiation releases, and economics.

  20. Interface Behavior in Functionally Graded Ceramics for the Magnetic Refrigeration: Numerical Modeling

    DEFF Research Database (Denmark)

    Jabbari, Masoud; Spangenberg, Jon; Hattel, Jesper Henri

    2013-01-01

    The active magnetic regenerator refrigerator is currently the most common magnetic refrigeration device for near room temperature applications, and it is driven by the magnetocaloric effect in the regenerator material. In order to make this efficient, a graded configuration of the magnetocaloric ...

  1. Standard test method for analysis of isotopic composition of uranium in nuclear-grade fuel material by quadrupole inductively coupled plasma-mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This test method is applicable to the determination of the isotopic composition of uranium (U) in nuclear-grade fuel material. The following isotopic weight percentages are determined using a quadrupole inductively coupled plasma-mass spectrometer (Q-ICP-MS): 233U, 234U, 235U, 236U, and 238U. The analysis can be performed on various material matrices after acid dissolution and sample dilution into water or dilute nitric (HNO3) acid. These materials include: fuel product, uranium oxide, uranium oxide alloys, uranyl nitrate (UNH) crystals, and solutions. The sample preparation discussed in this test method focuses on fuel product material but may be used for uranium oxide or a uranium oxide alloy. Other preparation techniques may be used and some references are given. Purification of the uranium by anion-exchange extraction is not required for this test method, as it is required by other test methods such as radiochemistry and thermal ionization mass spectroscopy (TIMS). This test method is also described i...

  2. A review of the environmental corrosion, fate and bioavailability of munitions grade depleted uranium

    Energy Technology Data Exchange (ETDEWEB)

    Handley-Sidhu, Stephanie, E-mail: s.handley-sidhu@bham.ac.uk [Water Sciences Research Group, School of Geography, Earth, Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Keith-Roach, Miranda J. [Biogeochemistry and Environmental Analytical Chemistry Research Group, and School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Lloyd, Jonathan R.; Vaughan, David J. [Williamson Research Centre for Molecular Environmental Science, and School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL (United Kingdom)

    2010-11-01

    Depleted uranium (DU) is a by-product of nuclear fuel enrichment and is used in antitank penetrators due to its high density, self-sharpening, and pyrophoric properties. Military activities have left a legacy of DU waste in terrestrial and marine environments, and there have been only limited attempts to clean up affected environments. Ten years ago, very little information was available on the dispersion of DU as penetrators hit their targets or the fate of DU penetrators left behind in environmental systems. However, the marked increase in research since then has improved our knowledge of the environmental impact of firing DU and the factors that control the corrosion of DU and its subsequent migration through the environment. In this paper, the literature is reviewed and consolidated to provide a detailed overview of the current understanding of the environmental behaviour of DU and to highlight areas that need further consideration.

  3. Recovery of uranium low grade ores by froth flotation: study of the texture and synergetic effects of flotation reagents

    International Nuclear Information System (INIS)

    Due to the energy growing demand, uranium low grade ores may be those exploited in the future. Uranium ores conventional treatment does not often use mineral processing such as concentration methods for reducing leaching reagent consumption. The aim of this work is to develop an upgrading process to improve the operating process (alkaline heap leaching) taking into account the mineralogical and textural variability of the ore. The Trekkopje deposit is composed of calcrete and a gypscrete. The uranium bearing mineral is carnotite (K2(UO2)2 [VO4]2.3H2O). The gangue minerals are composed by silicates, such as quartz, feldspars, micas and Ca-minerals, calcite and gypsum (XRD and ICP-MS analysis). A SEM image processing was used to study the textural properties and the exposed free surface of mineral inclusions in clay clusters. In calcrete milled to -200 μm, 50 % of all carnotite is associated with clay clusters, which are composed by 98 % of palygorskite, 2 % of illite, montmorillonite, and interbedded clays (XRD and microprobe analysis). The carnotite grain size is 95 % less than 70 μm. Calcite is the main inclusion in clay clusters. Indeed, the calcite inclusions average rate in the clay clusters is 12 % and 5 % for carnotite inclusion. And the free exposed surface percentage of these minerals in clay clusters is 3 % and 6 %, thus indicating that the inclusions should not affect the behavior of mixed clay particles. However, ore flotation essays did not verify this hypothesis. Three minerals separation have been proposed based on the mineral ability to consume leaching reagents: separating Ca-minerals from silicates, palygorskite from gangue minerals and carnotite from gangue minerals. A study of silicates and Ca-minerals electrokinetic properties (electrophoresis) was carried out to select the collectors and the optimum pH range for selective flotation. Basic pH near neutral was proved to be optimal for the separation of gangue minerals with cationic or anionic

  4. 功能梯度氧化锆全瓷修复体的研究进展%Research progress on functionally graded zirconia-based ceramic restoration

    Institute of Scientific and Technical Information of China (English)

    崔畅; 孙健

    2015-01-01

    氧化锆全瓷修复体目前已成为了口腔固定修复的主流技术,如何提高其修复成功率是一个研究热点。为提高材料的性能,功能梯度概念已在工业上广泛应用,同时也被引入了氧化锆全瓷修复领域。初步研究显示了其具有良好的临床性能。因此,功能梯度氧化锆全瓷修复体被誉为新一代的全瓷修复体。本文就功能梯度氧化锆全瓷修复体的概念由来、制备方法、力学性能及今后进一步的研究方向作一总结。%All-ceramic restoration is an attractive choice for dental prostheses. How to enhance the success rate is a hot topic of research. The concept of functional graded materials has been widely used in industry, which was introduced into zirconia-based all ceramic restoration in recent years. The initial research revealed excellent properties. And functionally graded zirconia-based ceramic restoration was regarded as the new generation of the all-ceramic restoration. This article summarized the concept, fabrication method, mechanical behavior and further research of the functionally graded zirconia-based ceramic restoration.

  5. Utilization of non-weapons-grade plutonium and highly enriched uranium with breeding of the {sup 233}U isotope in the VVER reactors using thorium and heavy water

    Energy Technology Data Exchange (ETDEWEB)

    Marshalkin, V. E., E-mail: marshalkin@vniief.ru; Povyshev, V. M. [Russian Federal Nuclear Center All-Russian Research Institute of Experimental Physics (Russian Federation)

    2015-12-15

    A method for joint utilization of non-weapons-grade plutonium and highly enriched uranium in the thorium–uranium—plutonium oxide fuel of a water-moderated reactor with a varying water composition (D{sub 2}O, H{sub 2}O) is proposed. The method is characterized by efficient breeding of the {sup 233}U isotope and safe reactor operation and is comparatively simple to implement.

  6. Standard specification for blended uranium oxides with 235U content of less than 5 % for direct hydrogen reduction to nuclear grade uranium dioxide

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This specification covers blended uranium trioxide (UO3), U3O8, or mixtures of the two, powders that are intended for conversion into a sinterable uranium dioxide (UO2) powder by means of a direct reduction process. The UO2 powder product of the reduction process must meet the requirements of Specification C 753 and be suitable for subsequent UO2 pellet fabrication by pressing and sintering methods. This specification applies to uranium oxides with a 235U enrichment less than 5 %. 1.2 This specification includes chemical, physical, and test method requirements for uranium oxide powders as they relate to the suitability of the powder for storage, transportation, and direct reduction to UO2 powder. This specification is applicable to uranium oxide powders for such use from any source. 1.3 The scope of this specification does not comprehensively cover all provisions for preventing criticality accidents, for health and safety, or for shipping. Observance of this specification does not relieve the user of th...

  7. Property of Uranium Nitride Ceramic Pellet by Hot Press Sintering%热压烧结 UN 陶瓷芯块的性能

    Institute of Scientific and Technical Information of China (English)

    尹邦跃; 屈哲昊

    2014-01-01

    Uranium nitride nuclear fuel has lots of advantages ,such as high uranium density ,high melt point ,high thermal conductivity ,low thermal expansion coefficient and high irradiation stability ,so it is an important candidate fuel for the future nuclear energy systems including space nuclear reactor ,nuclear rocket ,fast reactor and ADS . In this research ,U2N3 powders were fabricated by nitriding reaction of nitrogen and uranium powders .UN ceramic pellets with density of 93.5% TD (theory density) have a little residual metal uranium when U2 N3 powders with median particle size of 38.3 μm were hot press sintered in vacuum at 1 600 ℃ .But UN ceramic pellets can be vacuum hot press sintered to 96 .1% TD at 1 550 ℃ by 18.1 μm U2 N3 powders ,without residual uranium ,in w hich the total mass content of U and N is 99.57% ,the impurity content of each heavy metal is less than 50 μg/g ,the oxygen content is 1 048 μg/g ,and the car-bon content is 502 μg/g .U2 N3 will completely be decomposed into UN above 1 027 ℃ , and UN will also be decomposed above 1 627 ℃ .%UN燃料具有铀密度高、熔点高、热导率高、热膨胀系数低、辐照稳定性好等优点,是未来空间核电源、核火箭、快堆和ADS的重要候选燃料。本文采用金属铀粉与氮气在300~400℃直接发生化合反应,制得单相U2 N3粉末。粒度为38.3μm的 U2 N3粉末在1600℃真空热压烧结,制得相对密度为93.5%、存在少量金属铀相的U N陶瓷;而18.1μm的U2 N3粉末在1550℃真空热压烧结,制得相对密度为96.1%、不残留金属铀相的 U N陶瓷,U与N的总质量分数为99.57%,每个金属杂质含量均低于50μg/g ,氧含量为1048μg/g ,碳含量为502μg/g。U2 N3在1027℃以上将会完全分解成UN ,UN在1627℃以上也会发生分解。

  8. 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)

  9. Discussion of development and utilization prospect of low grade uranium resources in the south of Jiangxi province%赣南低品位铀矿资源开发利用前景探讨

    Institute of Scientific and Technical Information of China (English)

    曾飞云; 刘继忠; 寇子顺; 张春晖

    2012-01-01

    According to characteristics of low grade uranium resources from hard rock uranium deposits in the south of Jiangxi province, the amount of low grade uranium resources was predicted by reducing the cut-off grade of mining orebody and preliminary estimates of resource . Combined with production status and technical levels of mining and metallurgy, it is considered that reducing the cut-off grade of mining orebody and adopting efficient mining methods can make the low grade uranium resources in the south of Jiangxi province to get effective development and utilization.%根据赣南硬岩低品位铀矿资源的特点,通过降低矿床矿体开采的边界品位,初步测算矿床资源量,预测赣南低品位铀资源量,结合企业生产采冶技术现状,提出降低开采边界品位、采用高效采矿方法和强化堆浸、细菌堆浸等水冶技术,可有效开发利用赣南低品位铀资源.

  10. Utilization of low grade and waste uranium ores by means of biological processes. Part of a coordinated programme on bacterial leaching of uranium ores

    International Nuclear Information System (INIS)

    Investigation of the possible affect of bacteria in leaching uranium using alkaline carbonate medium has been investigated. Eleven strains of bacteria were isolated from the alkaline percolation solutions. Most belonged to the genus Thiobacillus. Each strain was characterized by growth under aerobic conditions in Levinthal - bouillon medium and under vaseline (semi-anaerobic in Hetehens medium. Growth of the bacteria was optimum at pH range 7 to 8 but a significant population was found to exist in alkaline leaching solutions of about pH 9 to 9.5 in heap leaching experiments. It was concluded that microbiological processes can play a role in alkaline heap leaching although the quantitative measure is yet uncertain

  11. Low-Enriched Uranium Fuel Design with Two-Dimensional Grading for the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ilas, Germina [ORNL; Primm, Trent [ORNL

    2011-05-01

    An engineering design study of the conversion of the High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel is ongoing at Oak Ridge National Laboratory. The computational models developed during fiscal year 2010 to search for an LEU fuel design that would meet the requirements for the conversion and the results obtained with these models are documented and discussed in this report. Estimates of relevant reactor performance parameters for the LEU fuel core are presented and compared with the corresponding data for the currently operating HEU fuel core. The results obtained indicate that the LEU fuel design would maintain the current performance of the HFIR with respect to the neutron flux to the central target region, reflector, and beam tube locations under the assumption that the operating power for the reactor fueled with LEU can be increased from the current value of 85 MW to 100 MW.

  12. Analytical Methods for Uranium Concentration Measurements

    International Nuclear Information System (INIS)

    A survey of analytical procedures for the determination of uranium, as performed for NMM in the United States of America, is presented. Methods are outlined for the measurement of the element in a variety of materials, i.e. ores, concentrates, uranium metal, alloys, ceramics, compounds of uranium, scrap processing solutions, residues, and waste stream products. It is not intended as a complete résumé dealing with the subject, but it does offer measurement methods believed to give precise and accurate results of a high order. Because of the monetary value of the materials, and the transfer activities from one installation to another, involving payments or credits, burn-up charges, use charges, etc., it is essential that such methods are used. Methods of analysis to a large extent are dictated by the types of material to be analysed. The use of gravimetric methods are reviewed pertaining to product materials, which are generally defined as uranium metal, or compounds of the metal, such as oxides, halides, or nitrates. A pyro-hydrolysis technique is included under this heading. Non-volatile metallic impurities are determined spectroscopically, and the gravimetric results are corrected accordingly. Volumetric procedures, the ''workhorse'' methods for determining uranium, are thoroughly explored. The technique is applicable to all types of material, providing the uranium available for measurement is present in milligram quantities. Due to the valence states of uranium, reduction-oxidation schemes are particularly attractive. Dissolution problems, separation of interfering elements, reduction steps, and oxidation titrations of reduced uranium are discussed. The application of certain spectrophotometric and fluorometric procedures for analysing low-grade materials are included. Various separation steps incorporated in the procedures before the determination of uranium are reviewed. Along these lines the utilization of differential colorimetry is examined for determining

  13. The Complete Burning of Weapons Grade Plutonium and Highly Enriched Uranium with (Laser Inertial Fusion-Fission Energy) LIFE Engine

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J C; Diaz de la Rubia, T; Moses, E

    2008-12-23

    The National Ignition Facility (NIF) project, a laser-based Inertial Confinement Fusion (ICF) experiment designed to achieve thermonuclear fusion ignition and burn in the laboratory, is under construction at the Lawrence Livermore National Laboratory (LLNL) and will be completed in April of 2009. Experiments designed to accomplish the NIF's goal will commence in late FY2010 utilizing laser energies of 1 to 1.3 MJ. Fusion yields of the order of 10 to 20 MJ are expected soon thereafter. Laser initiated fusion-fission (LIFE) engines have now been designed to produce nuclear power from natural or depleted uranium without isotopic enrichment, and from spent nuclear fuel from light water reactors without chemical separation into weapons-attractive actinide streams. A point-source of high-energy neutrons produced by laser-generated, thermonuclear fusion within a target is used to achieve ultra-deep burn-up of the fertile or fissile fuel in a sub-critical fission blanket. Fertile fuels including depleted uranium (DU), natural uranium (NatU), spent nuclear fuel (SNF), and thorium (Th) can be used. Fissile fuels such as low-enrichment uranium (LEU), excess weapons plutonium (WG-Pu), and excess highly-enriched uranium (HEU) may be used as well. Based upon preliminary analyses, it is believed that LIFE could help meet worldwide electricity needs in a safe and sustainable manner, while drastically shrinking the nation's and world's stockpile of spent nuclear fuel and excess weapons materials. LIFE takes advantage of the significant advances in laser-based inertial confinement fusion that are taking place at the NIF at LLNL where it is expected that thermonuclear ignition will be achieved in the 2010-2011 timeframe. Starting from as little as 300 to 500 MW of fusion power, a single LIFE engine will be able to generate 2000 to 3000 MWt in steady state for periods of years to decades, depending on the nuclear fuel and engine configuration. Because the fission

  14. Uranium induces oxidative stress in lung epithelial cells

    OpenAIRE

    Periyakaruppan, Adaikkappan; Kumar, Felix; Sarkar, Shubhashish; Sharma, Chidananda S.; Ramesh, Govindarajan T.

    2006-01-01

    Uranium compounds are widely used in the nuclear fuel cycle, antitank weapons, tank armor, and also as a pigment to color ceramics and glass. Effective management of waste uranium compounds is necessary to prevent exposure to avoid adverse health effects on the population. Health risks associated with uranium exposure includes kidney disease and respiratory disorders. In addition, several published results have shown uranium or depleted uranium causes DNA damage, mutagenicity, cancer and neur...

  15. Portfolio: Ceramics.

    Science.gov (United States)

    Hardy, Jane; And Others

    1982-01-01

    Describes eight art activities using ceramics. Elementary students created ceramic tiles to depict ancient Egyptian and medieval European art, made ceramic cookie stamps, traced bisque plates on sketch paper, constructed clay room-tableaus, and designed clay relief masks. Secondary students pit-fired ceramic pots and designed ceramic Victorian…

  16. The Chemistry and Toxicology of Depleted Uranium

    OpenAIRE

    Katz, Sidney A.

    2014-01-01

    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....

  17. Status of Uranium Conversion Plant Decommissioning

    International Nuclear Information System (INIS)

    KAERI (Korea Atomic Energy Research Institute) constructed a pilot plant for the uranium conversion process for the development of the technologies and the localization of nuclear fuels for HWR (heavy water reactor) in 1982. The final product of the plant was a UO2 powder of ceramic grade for HWR and its capacity was 100 ton-U/year. After that, a part of the AUC (Ammonium Uranyl Carbonate) process was added and the process was improved for automatic operation. 320 tons of UO2 powder was produced and supplied to the fabrication plant at KAERI for the fuel of the Wolsong-1 CANDU (Canadian deuterium uranium) reactor. The conversion plant has building area of 2916 m2 and two main conversion processes. ADU (Ammonium Di-Uranate) and AUC process are installed in the backside and the front side of the building, respectively. Conversion plant has two lagoons, which is to store all wastes generated from the plant operation. Sludge wastes stored 150m3 and 100m3 in Lagoon 1 and 2, respectively. Main compounds of sludge are ammonium nitrate, sodium nitrate, calcium nitrate, and calcium carbonate. In early 1992, it was determined that the plant operation would be stopped due to a much higher production cost than that of the international market. The conversion plant has been shutdown and minimally maintained for the prevention of contamination by deterioration of the equipment and the lagoon

  18. Standard specification for uranium metal enriched to more than 15 % and less Than 20 % 235U

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This specification covers nuclear grade uranium metal that has either been processed through an enrichment plant, or has been produced by the blending of highly enriched uranium with other uranium, to obtain uranium of any 235U concentration below 20 % (and greater than 15 %) and that is intended for research reactor fuel fabrication. The scope of this specification includes specifications for enriched uranium metal derived from commercial natural uranium, recovered uranium, or highly enriched uranium. Commercial natural uranium, recovered uranium and highly enriched uranium are defined in Section 3. The objectives of this specification are to define the impurity and uranium isotope limits for commercial grade enriched uranium metal. 1.2 This specification is intended to provide the nuclear industry with a standard for enriched uranium metal which is to be used in the production of research reactor fuel. In addition to this specification, the parties concerned may agree to other appropriate conditions. ...

  19. Determination of gas residues in uranium dioxide pellets

    International Nuclear Information System (INIS)

    The measurement of low amounts of residual gases, excluding water, in ceramic grade uranium dioxide pellets, using high temperature vacuum extraction technique, is dealt with. The high temperature extraction gas analysis apparatus was designed and assembled for sequential analysis of up to eight uranium dioxide pellets by run. The system consists of three major units, namely outgassing unit, transfer unit and analytical unit. The whole system is evacuated to a final pressure of less then 10-5 torr. A weighed pellet is transfered into the outgassing unit for subsequent dropping into a Platinum-Rhodium crucible which is heated inductively up to 16000C during 30 minutes. The released gases are imediately transfered from the outgassing to analytical unit passing through a cold trap at -950C to remove water vapor. The gases are transfered to previously calibrated volumetric bulb where the total pressure and temperature are determined. An estimate of the gas content in the pellets at STP condition is obtained from the measured volume, pressure and temperature of the gas mixture by applying ideal gases equation. Analysis to two lots (fourteen samples) of uranium dioxide pellets by the method described here indicated a mean gas content of 0,060cm3/g UO2. The lower limit of this technique is 0,03cm3/g UO2 (STP). The time required for the analysis of eight pellets is about 9 hours

  20. Quantified Grading Mode of Occupational Protection Measures in The Ceramic Industry%陶瓷行业职业卫生防护措施量化分级模式的探讨

    Institute of Scientific and Technical Information of China (English)

    陈松根; 黄燕玲; 李土华; 杨才

    2011-01-01

    The combination of quantified grading and supervision monitoring on occupational health management is a new pattern of supervision that shifted from supervising only to laying equal stress on supervising and technical guidance. Foshan Institute for Occupational Disease Prevention took 30 ceramic enterprises as respondents for investigation, and established quantified grading mode of occupational protection measures in the ceramic industry in Foshan between June. 2007 - December 2009. Under this approach, a remarkable achievement was made through supervision monitoring on ceramic enterprises and treatment on main occupational hazards in workplace. The qualified rate of total dust concentration in workplace air were increased by 30% after rectification; the qualified rate of respirable dust concentration and noise was increased by nearly 20% and 20%, respectively which indicates that protective measures have been well improved. But some ceramic enterprises have not rectified completely. In order to raise efficiency of supervision,to complete rectification early, and to accelerate adjustment and upgrade of ceramic industry, it is necessary to urge related functional departments to intensify supervision according to the quantified grading assessment program of occupational health inspection.%量化分级与监督监测相结合的职业卫生管理是一种将单纯监管转向监管与技术指导并重的新型监管模式.佛山市职业病防治所以该市2007年6月-2009年12月间30家陶瓷企业作为对象进行调查,建立陶瓷行业职业卫生防护措施量化分级模式,根据量化分级方案,对陶瓷企业进行监督监测,整治作业场所存在的主要职业危害因素,并取得一定的成效,整改后工作场所空气中生产性总尘浓度合格率比整改前提高了30.0%,呼尘浓度合格率比整改前提高了近20%,噪声合格率比整改前提高了20%,说明防护措施已得到很好的改善.但部分企业职业病

  1. Kvanefjeld uranium project

    International Nuclear Information System (INIS)

    The purpose of the Kvanefjeld uranium project is to evaluate the possibility of a uranium production from the deposit at Narssaq, South Greenland. The project comprises investigations in the fields of geology, mining, process chemistry and technology, economy and environment protection. The predominant uraniferous rock is a nepheline syenite called lujavrite in which the main uranium mineral is steenstrupine. The deposit can be mined in an open pit. Calculations have shown a resource of 56 million tonnes of ore with an average grade of 365 ppm corresponding to 20,400 tonnes of uranium. The uranium is extracted by a sodium carbonate solution at 260degC in an autoclave. A pilot plant has been established including ball mill, continuous pipe autoclave and a belt filter for separation of leach liquor and residue. The uranium is finally precipitated as UO2 by reduction in an autoclave at 260degC. With the existing ore sample, recoveries of more than 80% have been obtained. The carbonate leaching causes a low solubility of most contaminants in the tailings. A draft project has been prepared for an industrial plant in Greenland. The total investments have been calculated at 3 x 109 Dkr. Electrical energy is assumed to be supplied by a hydropower plant at Johan Dahl Land. The mine and mill are expected to employ 500-600 persons. (author)

  2. 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.

  3. Perspectives of Siberian chemical plant in increasing volumes of uranium concentrates recycling

    OpenAIRE

    Lazarchuk, V. V.; Shikerun, T. G.; Ryabov, A. S.; Shamin, V. I.; Zhiganov, A. N.

    2007-01-01

    The purification technology of uranium concentrate of natural isotopic composition developed at Siberian chemical enterprise is basically universal, allows recycling uranium concentrates with different content of impurities and obtaining uranium nitrate solutions corresponding by quality to the international standards requirements to uranium hexafluoride preparation for isotopes ASTM C 787-03 separation and to ceramic fuel ASTM C 788-02 preparation. Uranium reserves in Russia and abroad were ...

  4. On Ceramics.

    Science.gov (United States)

    School Arts, 1982

    1982-01-01

    Presents four ceramics activities for secondary-level art classes. Included are directions for primitive kiln construction and glaze making. Two ceramics design activities are described in which students make bizarrely-shaped lidded jars, feet, and footwear. (AM)

  5. Advanced Ceramics

    International Nuclear Information System (INIS)

    The First Florida-Brazil Seminar on Materials and the Second State Meeting about new materials in Rio de Janeiro State show the specific technical contribution in advanced ceramic sector. The others main topics discussed for the development of the country are the advanced ceramic programs the market, the national technic-scientific capacitation, the advanced ceramic patents, etc. (C.G.C.)

  6. Uranium in Canada

    International Nuclear Information System (INIS)

    In 1988 Canada's five uranium producers reported output of concentrate containing a record 12,470 metric tons of uranium (tU), or about one third of total Western world production. Shipments exceeded 13,200 tU, valued at $Cdn 1.1 billion. Most of Canada's uranium output is available for export for peaceful purposes, as domestic requirements represent about 15 percent of production. The six uranium marketers signed new sales contracts for over 11,000 tU, mostly destined for the United States. Annual exports peaked in 1987 at 12,790 tU, falling back to 10,430 tU in 1988. Forward domestic and export contract commitments were more than 70,000 tU and 60,000 tU, respectively, as of early 1989. The uranium industry in Canada was restructured and consolidated by merger and acquisition, including the formation of Cameco. Three uranium projects were also advanced. The Athabasca Basin is the primary target for the discovery of high-grade low-cost uranium deposits. Discovery of new reserves in 1987 and 1988 did not fully replace the record output over the two-year period. The estimate of overall resources as of January 1989 was down by 4 percent from January 1987 to a total (measured, indicated and inferred) of 544,000 tU. Exploration expenditures reached $Cdn 37 million in 1987 and $59 million in 1988, due largely to the test mining programs at the Cigar Lake and Midwest projects in Saskatchewan. Spot market prices fell to all-time lows from 1987 to mid-1989, and there is little sign of relief. Canadian uranium production capability could fall below 12,000 tU before the late 1990s; however, should market conditions warrant output could be increased beyond 15,000 tU. Canada's known uranium resources are more than sufficient to meet the 30-year fuel requirements of those reactors in Canada that are now or are expected to be in service by the late 1990s. There is significant potential for discovering additional uranium resources. Canada's uranium production is equivalent, in

  7. Disposal of Surplus Weapons Grade Plutonium

    International Nuclear Information System (INIS)

    The Office of Fissile Materials Disposition is responsible for disposing of inventories of surplus US weapons-usable plutonium and highly enriched uranium as well as providing, technical support for, and ultimate implementation of, efforts to obtain reciprocal disposition of surplus Russian plutonium. On January 4, 2000, the Department of Energy issued a Record of Decision to dispose of up to 50 metric tons of surplus weapons-grade plutonium using two methods. Up to 17 metric tons of surplus plutonium will be immobilized in a ceramic form, placed in cans and embedded in large canisters containing high-level vitrified waste for ultimate disposal in a geologic repository. Approximately 33 metric tons of surplus plutonium will be used to fabricate MOX fuel (mixed oxide fuel, having less than 5% plutonium-239 as the primary fissile material in a uranium-235 carrier matrix). The MOX fuel will be used to produce electricity in existing domestic commercial nuclear reactors. This paper reports the major waste-package-related, long-term disposal impacts of the two waste forms that would be used to accomplish this mission. Particular emphasis is placed on the possibility of criticality. These results are taken from a summary report published earlier this year

  8. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2000-10-01

    This is the third quarterly report on oxygen Transport Ceramic Membranes. In the following, the report describes the progress made by our university partners in Tasks 1 through 6, experimental apparatus that was designed and built for various tasks of this project, thermodynamic calculations, where applicable and work planned for the future. (Task 1) Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. (Task 2) Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. (Task 3) Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. (Task 4) Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. (Task 5) Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. (Task 6) Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

  9. Development of high-density ceramic composites for ballistic applications

    International Nuclear Information System (INIS)

    The application of ceramic composites for ballistic application has been generally developed with ceramics of low density, between 2.5 and 4.5 g/cm2. These materials have offered good performance in defeating small-caliber penetrators, but can suffer time-dependent degradation effects when thicker ceramic tiles are needed to defeat modem, longer, heavy metal penetrators that erode rather than break up. This paper addresses the ongoing development, fabrication procedures, analysis, and ballistic evaluation of thinner, denser ceramics for use in armor applications. Nuclear Metals Incorporated (NMI) developed a process for the manufacture of depleted uranium (DU) ceramics. Samples of the ceramics have been supplied to the US Army Research Laboratory (ARL) as part of an unfunded cooperative study agreement. The fabrication processes used, characterization of the ceramic, and a ballistic comparison between the DU-based ceramic with baseline Al2O3 will be presented

  10. Ballistic performance and microstructure of four armor ceramics

    NARCIS (Netherlands)

    Abadjieva, E.; Carton, E.P.

    2013-01-01

    The ballistic behavior of four different armor ceramic materials with thicknesses varying from 3 mm to 14 mm has been investigated. These are two types of alumina Al2O3 armor grades and two types of SiC armor grades produced by different armor ceramic producers. The ballistic study has been performe

  11. Ceramic joining

    Energy Technology Data Exchange (ETDEWEB)

    Loehman, R.E. [Sandia National Lab., Albuquerque, NM (United States)

    1996-04-01

    This paper describes the relation between reactions at ceramic-metal interfaces and the development of strong interfacial bonds in ceramic joining. Studies on a number of systems are described, including silicon nitrides, aluminium nitrides, mullite, and aluminium oxides. Joints can be weakened by stresses such as thermal expansion mismatch. Ceramic joining is used in a variety of applications such as solid oxide fuel cells.

  12. Ceramic Processing

    Energy Technology Data Exchange (ETDEWEB)

    EWSUK,KEVIN G.

    1999-11-24

    Ceramics represent a unique class of materials that are distinguished from common metals and plastics by their: (1) high hardness, stiffness, and good wear properties (i.e., abrasion resistance); (2) ability to withstand high temperatures (i.e., refractoriness); (3) chemical durability; and (4) electrical properties that allow them to be electrical insulators, semiconductors, or ionic conductors. Ceramics can be broken down into two general categories, traditional and advanced ceramics. Traditional ceramics include common household products such as clay pots, tiles, pipe, and bricks, porcelain china, sinks, and electrical insulators, and thermally insulating refractory bricks for ovens and fireplaces. Advanced ceramics, also referred to as ''high-tech'' ceramics, include products such as spark plug bodies, piston rings, catalyst supports, and water pump seals for automobiles, thermally insulating tiles for the space shuttle, sodium vapor lamp tubes in streetlights, and the capacitors, resistors, transducers, and varistors in the solid-state electronics we use daily. The major differences between traditional and advanced ceramics are in the processing tolerances and cost. Traditional ceramics are manufactured with inexpensive raw materials, are relatively tolerant of minor process deviations, and are relatively inexpensive. Advanced ceramics are typically made with more refined raw materials and processing to optimize a given property or combination of properties (e.g., mechanical, electrical, dielectric, optical, thermal, physical, and/or magnetic) for a given application. Advanced ceramics generally have improved performance and reliability over traditional ceramics, but are typically more expensive. Additionally, advanced ceramics are typically more sensitive to the chemical and physical defects present in the starting raw materials, or those that are introduced during manufacturing.

  13. USTUR case 0259 whole body donation: a comprehensive test of the current ICRP models for the behavior of inhaled 238PuO2 ceramic particles. U.S. Transuranium and Uranium Registries.

    Science.gov (United States)

    James, A C; Filipy, R E; Russell, J J; McInroy, J F

    2003-01-01

    An analysis of 238Pu in the whole body donation to the U.S. Transuranium and Uranium Registries (USTUR) is presented. This donor accidentally inhaled an unusual physical form of plutonium, predominantly the 238Pu isotope in the form of a highly insoluble ceramic. Along with six other workers accidentally exposed at the same time, this donor excreted little or no 238Pu in his urine for several months. Subsequently, however, and, with no further intakes, the urinary excretion of 238Pu by all of these workers increased progressively. Such a pattern of increasing urinary excretion of plutonium resulting from a single acute inhalation was unknown at the time. The subject of this study provided a unique opportunity to analyze not only the pattern of urinary excretion for 17 y following this unusual intake but also the complete distribution of 238Pu in his donated body tissues and skeleton at death. Radiochemical analyses of tissues from this whole body donation were used to perform critical tests of the applicability and accuracy of the respiratory tract model and the systemic biokinetic models for plutonium currently recommended by the International Commission on Radiological Protection. The respiratory tract model was applied to analyze the donor's long-term urinary excretion pattern. The facility provided by this model to represent progressive transformation of insoluble particles in the lungs into a more soluble form, applied in conjunction with the systemic biokinetic model, predicted the total amount of 238Pu measured in the donor's body to within 17% accuracy. The measured division of 238Pu between the donor's lungs and systemic organs was predicted to within 10%. Small adjustments to several rate constants in these models provided precise predictions of the absolute amounts of 238Pu in the lungs, thoracic lymph nodes, liver, red bone marrow, skeleton (including the distribution of 238Pu between trabecular and cortical bone matrices derived from the radiochemical

  14. FY2015 ceramic fuels development annual highlights

    Energy Technology Data Exchange (ETDEWEB)

    Mcclellan, Kenneth James [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

    2015-09-22

    Key challenges for the Advanced Fuels Campaign are the development of fuel technologies to enable major increases in fuel performance (safety, reliability, power and burnup) beyond current technologies, and development of characterization methods and predictive fuel performance models to enable more efficient development and licensing of advanced fuels. Ceramic fuel development activities for fiscal year 2015 fell within the areas of 1) National and International Technical Integration, 2) Advanced Accident Tolerant Ceramic Fuel Development, 3) Advanced Techniques and Reference Materials Development, and 4) Fabrication of Enriched Ceramic Fuels. High uranium density fuels were the focus of the ceramic fuels efforts. Accomplishments for FY15 primarily reflect the prioritization of identification and assessment of new ceramic fuels for light water reactors which have enhanced accident tolerance while also maintaining or improving normal operation performance, and exploration of advanced post irradiation examination techniques which will support more efficient testing and qualification of new fuel systems.

  15. Uranium enrichment

    International Nuclear Information System (INIS)

    GAO was asked to address several questions concerning a number of proposed uranium enrichment bills introduced during the 100th Congress. The bill would have restructured the Department of Energy's uranium enrichment program as a government corporation to allow it to compete more effectively in the domestic and international markets. Some of GAO's findings discussed are: uranium market experts believe and existing market models show that the proposed DOE purchase of a $750 million of uranium from domestic producers may not significantly increase production because of large producer-held inventories; excess uranium enrichment production capacity exists throughout the world; therefore, foreign producers are expected to compete heavily in the United States throughout the 1990s as utilities' contracts with DOE expire; and according to a 1988 agreement between DOE's Offices of Nuclear Energy and Defense Programs, enrichment decommissioning costs, estimated to total $3.6 billion for planning purposes, will be shared by the commercial enrichment program and the government

  16. Tramp uranium

    International Nuclear Information System (INIS)

    Many utilities have implemented a no leaker philosophy for fuel performance and actively pursue removing leaking fuel assemblies from their reactor cores whenever a leaking fuel assembly is detected. Therefore, the only source for fission product activity in the RCS when there are no leaking fuel assemblies is tramp uranium. A technique has been developed that strips uranium impurities from ZrCl4. Unless efforts are made to remove natural uranium impurities from reactor materials, the utilities will not be able to reduce the RCS specific 131I activity in PWRs to below the lower limit of ∼1.0 x 10-4 μCi/g

  17. Uranium Market

    International Nuclear Information System (INIS)

    The main fuel component for commercial nuclear power reactors is Uranium. When compared to fossil fuels, it has a competitive edge due to factors such as economics and environmental conditions and in particular due to its international market availability. Uranium world demand reached to 67 320 tU in 2004, which was covered with additional sources. To project the uranium markets behavior requires to know and to accept some conditions tied to the demand, such as the electrical world consumption, the greenhouse effect; water desalination, production of hydrogen, industrial heat, the innovative development of nuclear reactors, and the average time of 10 years between the beginning of exploration programs and definition of deposits, which it owes mainly to the difficulty of achieving the legal, environmental and local community authorizations, to open new mining centers. Uranium market future projections, made by IAEA experts in 2001, that considered middle and high demand scenarios, concluded that cumulatively to year 2050, with regard to demand it will be required 5.4 and 7.6 million tons of uranium respectively, and with regard to the uranium price, it should present a sustained increase. In the last years the situation of the uranium market has changed dramatically. In August 2006 the price of uranium reached to USD 106/kgU in the spot market, surpassing all the made projections. The increase in price that has stayed in rise in the last five years is reactivating the prospection and exploration efforts anywhere in the world, and competition between prospective areas of potential resources mainly in less explored territories

  18. Uranium dioxide sintering Kinetics and mechanisms under controlled oxygen potentials

    International Nuclear Information System (INIS)

    The initial, intermediate, and final sintering stages of uranium dioxide were investigated as a function of stoichiometry and temperature by following the kinetics of the sintering reaction. Stoichiometry was controlled by means of the oxygen potential of the sintering atmosphere, which was measured continuously by solid-state oxygen sensors. Included in the kinetic study were microspheres originated from UO2 gels and UO2 pellets produced by isostatic pressing ceramic grade powders. The microspheres sintering behavior was examined using hot-stage microscopy and a specially designed high-temperature, controlled atmosphere furnace. This same furnace was employed as part of an optical dilatometer, which was utilized in the UO2 pellet sintering investigations. For controlling the deviations from stoichiometry during heat treatment, the oxygen partial pressure in the sintering atmosphere was varied by passing the gas through a Cu-Ti-Cu oxygen trap. The trap temperature determined the oxygen partial pressure of the outflowing mixture. Dry hydrogen was also used in some of the UO sub(2+x) sintering experiments. The determination of diametrial shrinkages and sintering indices was made utilizing high-speed microcinematography and ultra-microbalance techniques. It was observed that the oxygen potential has a substantial influence on the kinetics of the three sintering stages. The control of the sintering atmosphere oxygen partial pressure led to very fast densification of UO sub(2+x). Values in the interval 95.0 to 99.5% of theoretical density were reached in less than one minute. Uranium volume diffusion is the dominant mechanism in the initial and intermediate sintering stages. For the final stage, uranium grain boundary diffusion was found to be the main sintering mechanism. (Author)

  19. Engineering ceramics

    CERN Document Server

    Bengisu, Murat

    2001-01-01

    This is a comprehensive book applying especially to junior and senior engineering students pursuing Materials Science/ Engineering, Ceramic Engineering and Mechanical Engineering degrees. It is also a reference book for other disciplines such as Chemical Engineering, Biomedical Engineering, Nuclear Engineering and Environmental Engineering. Important properties of most engineering ceramics are given in detailed tables. Many current and possible applications of engineering ceramics are described, which can be used as a guide for materials selection and for potential future research. While covering all relevant information regarding raw materials, processing properties, characterization and applications of engineering ceramics, the book also summarizes most recent innovations and developments in this field as a result of extensive literature search.

  20. Tailored ceramics

    International Nuclear Information System (INIS)

    In polyphase tailored ceramic forms two distinct modes of radionuclide immobilization occur. At high waste loadings the radionuclides are distributed through most of the ceramic phases in dilute solid solution, as indicated schematically in this paper. However, in the case of low waste loadings, or a high loading of a waste with low radionuclide content, the ceramic can be designed with only selected phases containing the radionuclides. The remaining material forms nonradioactive phases which provide a degree of physical microstructural isolation. The research and development work with polyphase ceramic nuclear waste forms over the past ten years is discussed. It has demonstrated the critical attributes which suggest them as a waste form for future HLW disposal. From a safety standpoint, the crystalline phases in the ceramic waste forms offer the potential for demonstrable chemical durability in immobilizing the long-lived radionuclides in a geologic environment. With continued experimental research on pure phases, analysis of mineral analogue behavior in geochemical environments, and the study of radiation effects, realistic predictive models for waste form behavior over geologic time scales are feasible. The ceramic forms extend the degree of freedom for the economic optimization of the waste disposal system

  1. Glass, Ceramics, and Composites

    International Nuclear Information System (INIS)

    Many studies of plutonium in glass and ceramics have taken place in the thirty years covered by this book. These studies have led to a substantial understanding, arising from fundamental research of actinides in solids and research and development in three technical fields: immobilization of the high level wastes (HLW) from commercial nuclear power plants and processing of nuclear weapons materials, environmental restoration in the nuclear weapons complex and, most recently, the immobilization of weapons-grade plutonium as a result of disarmament activities

  2. Structural Ceramics Database

    Science.gov (United States)

    SRD 30 NIST Structural Ceramics Database (Web, free access)   The NIST Structural Ceramics Database (WebSCD) provides evaluated materials property data for a wide range of advanced ceramics known variously as structural ceramics, engineering ceramics, and fine ceramics.

  3. Uranium enrichment

    International Nuclear Information System (INIS)

    Canada is the world's largest producer and exporter of uranium, most of which is enriched elsewhere for use as fuel in LWRs. The feasibility of a Canadian uranium-enrichment enterprise is therefore a perennial question. Recent developments in uranium-enrichment technology, and their likely impacts on separative work supply and demand, suggest an opportunity window for Canadian entry into this international market. The Canadian opportunity results from three particular impacts of the new technologies: 1) the bulk of the world's uranium-enrichment capacity is in gaseous diffusion plants which, because of their large requirements for electricity (more than 2000 kW·h per SWU), are vulnerable to competition from the new processes; 2) the decline in enrichment costs increases the economic incentive for the use of slightly-enriched uranium (SEU) fuel in CANDU reactors, thus creating a potential Canadian market; and 3) the new processes allow economic operation on a much smaller scale, which drastically reduces the investment required for market entry and is comparable with the potential Canadian SEU requirement. The opportunity is not open-ended. By the end of the century the enrichment supply industry will have adapted to the new processes and long-term customer/supplier relationships will have been established. In order to seize the opportunity, Canada must become a credible supplier during this century

  4. Moving to world's best uranium address

    International Nuclear Information System (INIS)

    , which owns and operates the Beverley uranium mine. The JV has just received native title clearance and is awaiting the availability of drill rigs to recommence drilling adjacent to hole AK051, which intersected uranium mineralisation at an average grade of 0.44% eU3O8. Copyright (2006) Reed Business Information

  5. Uranium occurrences of the Thunder Bay-Nipigon-Marathon area

    International Nuclear Information System (INIS)

    During the 1981, 1982 and 1983 field seasons an inventory of all known uranium occurrences in the North Central Region of Ontario was undertaken. Three major categories of uranium occurrences were identified: uranium associated with the rocks of the Quetico Subprovince; uranium associated with the Proterozoic/Archean unconformity; and uranium associated with alkalic and carbonatite rocks of Late Precambrian age. Occurrences associated with the Quetico Belt are in white, albite-quartz-muscovite pegmatites. Occurrences associated with the Proterozoic/Archean unconformity are usually of high gradee (up to 12% U3O8), nearly always hematized and are related to fault or shear zones proximal to the unconformity. Although of high grade, many of the unconformity related occurrences are very narrow (<1 m). Alkalic and carbonatite rocks of Late Precambrian age are an important source of uranium but possible metallurgical problems might downgrade their potential. The Quetico Subprovince is anomalously high in background uranium, and therefore contains important source rocks for uranium. Areas that have the highest potential for uranium deposits in the North Central Region are the Nipigon Basin area, and the areas underlain by the Gunflint and Rove Formations. All the high grade vein-type uranium deposits related to the unconformity are found within the Nipigon Basin. 126 refs

  6. Evaluation of some ceramic clays from Zambia

    OpenAIRE

    Mitchell, C J

    1993-01-01

    This reports details the technical evaluation of ceramic clays collected during visits to Zambia in 1990 and 1991 by the author (Clive Mitchell). The clay samples included: Choma kaolin (Southern Province), Twapia kaolin (Copperbelt Province), Kapiri Mposhi kaolin (Central Province), Masenche clay (Northern Province), Leula clay, Misenga clay and Chikankata clay (Southern Province). The Choma kaolin was asessed to be an excellent source of ceramic-grade kaolin. The Twapia and Kapiri Mposhi ka...

  7. Uranium industry annual 1996

    International Nuclear Information System (INIS)

    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

  8. 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.

  9. Uranium industry annual, 1991

    International Nuclear Information System (INIS)

    In the Uranium Industry Annual 1991, 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. A feature article entitled ''The Uranium Industry of the Commonwealth of Independent States'' is included in this report

  10. Technology and the uranium industry

    International Nuclear Information System (INIS)

    Continuing economic and regulatory pressures on the uranium industry can be countered only through advances in technology. Low prices, the 'ALARA' principle, and concerns about 'sustainability' require the industry to continually improve upon its already impressive record of performance. Technological improvement in the uranium industry is necessary in order to: 1) Maintain our resource base through the discovery of ever deeper deposits; 2) Improve the efficiency with which we may exploit - a) very high-grade deposits by remote underground mining methods - b) very low-grade deposits with environmentally-benign, in situ, leaching methods - and c) moderate-grade, near-surface deposits by open-pit mining methods; 3) Meet increasingly stringent and, in many cases, arbitrary and unrealistic environmental and safety requirements; and 4) Cope with increasing competition from an expanding number of sources of secondary supply. Manifestations of the uranium industry's ability to improve its performance through technology can be seen in many ways including: a continuing reduction in production costs; large gains in productivity; and a truly superior record of employee safety. Maintenance of these trends requires both innovation and the open sharing of information. (author)

  11. Technology and the uranium industry

    International Nuclear Information System (INIS)

    Continuing economic and regulatory pressures on the uranium industry can be countered only through advances in technology. Low prices, the 'ALARA' principle, and concerns about 'sustainability' require the industry to continually improve upon its already impressive record of performance. Technological improvement in the uranium industry is necessary in order to: (a) Maintain our resource base through the discovery of ever deeper deposits; (b) Improve the efficiency with which we may exploit (i) very high-grade deposits by remote underground mining methods (ii) very low-grade deposits with environmentally-benign, in situ leaching methods - and (iii) moderate-grade, near-surface deposits by open-pit mining methods (c) Meet increasingly stringent and, in many cases, arbitrary and unrealistic environmental and safety requirements; and (d) Cope with increasing competition from an expanding number of sources of secondary supply. Manifestations of the uranium industry's ability to improve its performance through technology can be seen in many ways including: a continuing reduction in production costs; large gains in productivity; and a truly superior record of employee safety. Maintenance of these trends requires both innovation and the open sharing of information. (author)

  12. Uranium induces oxidative stress in lung epithelial cells

    International Nuclear Information System (INIS)

    Uranium compounds are widely used in the nuclear fuel cycle, antitank weapons, tank armor, and also as a pigment to color ceramics and glass. Effective management of waste uranium compounds is necessary to prevent exposure to avoid adverse health effects on the population. Health risks associated with uranium exposure includes kidney disease and respiratory disorders. In addition, several published results have shown uranium or depleted uranium causes DNA damage, mutagenicity, cancer and neurological defects. In the current study, uranium toxicity was evaluated in rat lung epithelial cells. The study shows uranium induces significant oxidative stress in rat lung epithelial cells followed by concomitant decrease in the antioxidant potential of the cells. Treatment with uranium to rat lung epithelial cells also decreased cell proliferation after 72 h in culture. The decrease in cell proliferation was attributed to loss of total glutathione and superoxide dismutase in the presence of uranium. Thus the results indicate the ineffectiveness of antioxidant system's response to the oxidative stress induced by uranium in the cells. (orig.)

  13. Effective use of uranium resources in light water reactor system

    International Nuclear Information System (INIS)

    We have proposed an idea of recycling uranium recovered from spent fuels of light water reactors (LWRs), where the recovered uranium is to be re-enriched by a centrifuge cascade conventionally treating natural uranium. The idea is of making it possible to reuse the fuels reproduced in a multi-cycle of re-enrichment. The uranium recycle not only economizes on uranium resources but also gets rid of accumulation of spent fuel masses. In this work, we consider additional processes for effective use of uranium, which are of re-enriching the depleted uranium. The still-more-depleted uranium is advantageous as the matrix of MOX fuels used in LWRs for the purpose of surplus plutonium disposition, because a decrease of 235U in MOX fuel is made up by increasing a dose of plutonium. However, the depleted uranium derived from the cascade enriching the recovered uranium issues a little troublesome problem of 236U concerning its existence and deliveries to the product and the waste. We made a work to investigate the burn-up performance of these remade uranium fuels in model reactors of 1.1GWe-grade PWR and the mass balance in fuel recycles. The results suggest a strategy of effective use of uranium resources in the LWR system. (author)

  14. Uranium enrichment

    International Nuclear Information System (INIS)

    This paper reports that in 1990 the Department of Energy began a two-year project to illustrate the technical and economic feasibility of a new uranium enrichment technology-the atomic vapor laser isotope separation (AVLIS) process. GAO believes that completing the AVLIS demonstration project will provide valuable information about the technical viability and cost of building an AVLIS plant and will keep future plant construction options open. However, Congress should be aware that DOE still needs to adequately demonstrate AVLIS with full-scale equipment and develop convincing cost projects. Program activities, such as the plant-licensing process, that must be completed before a plant is built, could take many years. Further, an updated and expanded uranium enrichment analysis will be needed before any decision is made about building an AVLIS plant. GAO, which has long supported legislation that would restructure DOE's uranium enrichment program as a government corporation, encourages DOE's goal of transferring AVLIS to the corporation. This could reduce the government's financial risk and help ensure that the decision to build an AVLIS plant is based on commercial concerns. DOE, however, has no alternative plans should the government corporation not be formed. Further, by curtailing a planned public access program, which would have given private firms an opportunity to learn about the technology during the demonstration project, DOE may limit its ability to transfer AVLIS to the private sector

  15. Uranium industry annual, 1986

    International Nuclear Information System (INIS)

    Uranium industry data collected in the EIA-858 survey provide a comprehensive statistical characterization of annual activities of the industry and include some information about industry plans over the next several years. This report consists of two major sections. The first addresses uranium raw materials activities and covers the following topics: exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment. The second major section is concerned with the following uranium marketing activities: uranium purchase commitments, uranium prices, procurement arrangements, uranium imports and exports, enrichment services, inventories, secondary market activities utility market requirements and related topics

  16. Optimization of ceramic strength using elastic gradients

    OpenAIRE

    Zhang, Yu; Ma, Li

    2009-01-01

    We present a new concept for strengthening ceamics by utilizing a graded structure with a low elastic modulus at both top and bottom surfaces sandwiching a high-modulus interior. Closed-form equations have been developed for stress analysis of simply supported graded sandwich beams subject to transverse center loads. Theory predicts that suitable modulus gradients at the ceramic surface can effectively reduce and spread the maximum bending stress from the surface into the interior. The magnit...

  17. Trace elements in ancient ceramics: Pt.4

    International Nuclear Information System (INIS)

    In the last period of Tong Dynasty, Jingdezhen began its production of ceramics. During the Song Dynasty, the ceramic industry greatly developed and produced fine white ware at Hutian. In the Yuan Dynastry, Hutian became the centre of production making the world famous blue and white wares. Here are reported results of analyses of ancient porcelians of Hutian in Jiangdezhen by reactor neutron activation analysis. The results show that the patterns of eight rare earth elements are apparently different for products in different periods, indicating that methods for producing ceramics or kinds of clay used were different. The contents of some other trace elements such as hafnium, tantalum, thorium and uranium show the same regularity in difference of composition also

  18. Uranium Industry Annual, 1992

    International Nuclear Information System (INIS)

    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

  19. 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.

  20. Migration and gamma ray assessment of uranium on a gold tailings disposal facility / Jaco Koch

    OpenAIRE

    Koch, Jaco

    2014-01-01

    This project aims to quantify natural gamma radiation in gold tailings disposal facilities (TDFs) relative to uranium concentration data in order to use natural gamma detection methods as alternative methods for uranium resource estimation modelling in gold tailings. Uranium migration within the New Machavie TDF was also investigated as migration affects both the grade of the TDF as a uranium resource and poses a threat to the environment. In order to determine the most appropr...

  1. Statistical data of the uranium industry

    International Nuclear Information System (INIS)

    The ''Statistical Data of the Uranium Industry'' is a compilation of historical facts and figures through 1976. These statistics are based primarily on information provided voluntarily by the uranium exploration, mining, and milling companies. This publication is compiled and revised annually by the Grand Junction Office. The production and ore reserve information has been compiled in a manner which avoids disclosure of proprietary information. Due to increased interest in higher-cost and lower-grade resources, four new categories of information are provided: (1) an estimate of the $50 per pound or less reserves and potential resources (p. 21-22, 26, 43), (2) preproduction and postproduction uranium mineral inventories (p. 34-39), (3) size-depth-thickness and size-grade matrices (p. 64-70), and (4) average U3O8 prices for delivery commitments

  2. Uranium resources, production and fuel fabrication

    International Nuclear Information System (INIS)

    Almost all the known disseminated and vein-type uranium deposits in India are located in the Precambrian igneous and metamorphic complexes in the Peninsular Shield; the most significant reserves occur in the Singhbhum Thrust Belt of Bihar. Adequate resources of uranium to meet the country's fuel requirements for the nuclear power programme have been established. The Uranium Corporation of India has been operating commercially an underground uranium mine and a mill at Jaduguda (Bihar) since 1968. The uranium ore body is mined by the cut-and-fill method. The present mine workings, 530 m below ground level, comprise many innovative features, namely, a tower-mounted Koepe winder system, skip-loading with an underground crushing system, concrete headframe, etc. Surveillance, control and monitoring systems, especially required in the mining of low grade uranium ores, have been successfully introduced. The uranium mill adjacent to the mine uses the acid leach and ion-exchange processes of recovery. The effluents are suitably treated in a specially designed tailings pond. Other accessory economic minerals, namely chalcopyrite, molybdenite and magnetite, are profitably recovered as by-products. Fuel fabrication commenced in India with the manufacture of aluminium-clad metallic uranium fuel for the CIR reactor. Power reactor oxide fuel manufacture has been carried out initially at Trombay for the Rajasthan Power Reactor I (RAPP-I). For transferring the technology developed, industrial-scale plants have been set up in the Nuclear Fuel Complex (NFC) at Hyderabad for the manufacture of zirconium-clad natural uranium fuel for PHWRs and low enrichment uranium fuel for the BWR Tarapur Power Station

  3. Heap leaching of clay ish uranium ores

    International Nuclear Information System (INIS)

    This paper describes an experimental facility, built near El Lobo mine. In it we study the beneficiation of low-grade uranium ore. The mineral has a great amount of clay and fines. The flow-sheet used has four steps: head leaching, ph-ajustement, ion-exchange and participation. We show, also, the most interesting results. (Author)

  4. Uranium Surface Mine reclamation in South Texas

    International Nuclear Information System (INIS)

    Reclamation of Surface Mining for Uranium in South Texas has changed since the early 1960's. The paper reviews current reclamation procedures including the use of vegetation, grade stabilization structures, rainfall runoff management, use of computers in planning, evaluation and design, and considerations for long term management of reclaimed mine sites

  5. Jabiluka gold-uranium project

    International Nuclear Information System (INIS)

    The Jabiluka gold-uranium deposit, 230km east of Darwin in the Alligator Rivers Region of the Northern Territory, was discovered by Pancontinental Mining Limited in 1971. Jabiluka, with reserves in excess of 200,000 tonnes of contained U3O8 in two deposits 500 metres apart, is the world's largest high grade uranium deposit and also contains nearly 12 tonnes of gold. It is proposed that only the larger deposit, Jabiluka II will be mined - by underground extraction methods, and that 275,000 tonnes of ore per year will be mined and processed to produce 1,500 tonnes of U3O8 and up to 30,000 oz of gold. The revenue from the uranium sales is estimated to be of the order of A$100 million per year at A$30/lb. By the end of 1982 all necessary mining and environmental approvals had been obtained and significant marketing progress made. With the Australian Labor Party winning Commonwealth Government in the 1983 election, Pancontinental's permission to seek sales contracts was withdrawn and development of the Jabiluka deposit ceased. Jabiluka remains undeveloped - awaiting a change in Australian Government policy on uranium. figs., maps

  6. 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

  7. Issues in uranium availability

    International Nuclear Information System (INIS)

    The purpose of this publication is to show the process by which information about uranium reserves and resources is developed, evaluated and used. The following three papers in this volume have been abstracted and indexed for the Energy Data Base: (1) uranium reserve and resource assessment; (2) exploration for uranium in the United States; (3) nuclear power, the uranium industry, and resource development

  8. Field measurements of mixed exposure of operators to radioactive aerosol, gas and quartz in confinement of mining equipment cabs during open-pit mining of high-grade uranium ores

    International Nuclear Information System (INIS)

    A series of field measurements of miners mixed exposure to radon and daughters, uranium ore dust and respirable quartz, was conducted in an open-pit mine in Northern Saskatchewan during 1980-81. Control of radon gas levels in the mining equipment cabs is required. Dust may be reduced by minimizing the resuspension of dust from contaminated surfaces within the cabs

  9. Uranium industry annual 1985

    International Nuclear Information System (INIS)

    This report consists of two major sections. The first addresses uranium raw materials activities and covers the following topics: exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment. The second major section is concerned with the following uranium marketing activities: uranium purchase commitments, uranium prices, procurement arrangements, uranium imports and exports, enrichment services, inventories, secondary market activities, utility market requirements, and related topics. A glossary and appendices are included to assist the reader in interpreting the substantial array of statistical data in this report and to provide background information about the survey

  10. Dental ceramics: An update

    OpenAIRE

    Shenoy Arvind; Shenoy Nina

    2010-01-01

    In the last few decades, there have been tremendous advances in the mechanical properties and methods of fabrication of ceramic materials. While porcelain-based materials are still a major component of the market, there have been moves to replace metal ceramics systems with all ceramic systems. Advances in bonding techniques have increased the range and scope for use of ceramics in dentistry. In this brief review, we will discuss advances in ceramic materials and fabrication techniques. Examp...

  11. New developments on the uranium sector in Australia

    International Nuclear Information System (INIS)

    Australia is one of the richest countries as far as uranium is concerned. The Jabiluka deposit alone is considered to be the largest single uranium deposit of the Western world. The overall known assured uranium reserves in Australia amount to 465.000 tons U3O8 at cost ranges between 15 and 30 US Dollar per pound U3O8, i.e. approximately 21% of the known world reserves. Most of the Australien uranium ore is of relatively high grade and nearly all of it could be mined from open pit. At this stage Mary Kathleen in Queensland is the only producing uranium mine in Australia. The actual political attitude of the Australian government prevents the Australian uranium industry from beeing further developed. (orig.) 891 HP/orig. 892 MKO

  12. Depleted Uranium Management

    International Nuclear Information System (INIS)

    The paper considers radiological and toxic impact of the depleted uranium on the human health. Radiological influence of depleted uranium is less for 60 % than natural uranium due to the decreasing of short-lived isotopes uranium-234 and uranium-235 after enrichment. The formation of radioactive aerosols and their impact on the human are mentioned. Use of the depleted uranium weapons has also a chemical effect on intake due to possible carcinogenic influence on kidney. Uranium-236 in the substance of the depleted uranium is determined. The fact of beta-radiation formation in the uranium-238 decay is regarded. This effect practically is the same for both depleted and natural uranium. Importance of toxicity of depleted uranium, as the heavier chemical substance, has a considerable contribution to the population health. The paper analyzes risks regarding the use of the depleted uranium weapons. There is international opposition against using weapons with depleted uranium. Resolution on effects of the use of armaments and ammunitions containing depleted uranium was five times supported by the United Nations (USA, United Kingdom, France and Israel did not support). The decision for banning of depleted uranium weapons was supported by the European Parliament

  13. 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

  14. Uranium management activities

    International Nuclear Information System (INIS)

    One of the missions of the Department of Energy's (DOE) Oak Ridge Office (ORO) has been the management of the Department's uranium materials. This mission has been accomplished through successful integration of ORO's uranium activities with the rest of the DOE complex. Beginning in the 1980's, several of the facilities in that complex have been shut down and are in the decommissioning process. With the end of the Cold War, the shutdown of many other facilities is planned. As a result, inventories of uranium need to be removed from the Department facilities. These inventories include highly enriched uranium (HEU), low enriched uranium (LEU), normal uranium (NU), and depleted uranium (DU). The uranium materials exist in different chemical forms, including metals, oxides, solutions, and gases. Much of the uranium in these inventories is not needed to support national priorities and programs. (author)

  15. 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.

  16. 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.

  17. 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.

  18. Uranium industry annual 1994

    International Nuclear Information System (INIS)

    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

  19. Uranium: one utility's outlook

    International Nuclear Information System (INIS)

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

  20. Uranium health physics

    International Nuclear Information System (INIS)

    This report contains the papers delivered at the Summer School on Uranium Health Physics held in Pretoria on the 14 and 15 April 1980. The following topics were discussed: uranium producton in South Africa; radiation physics; internal dosimetry and radiotoxicity of long-lived uranium isotopes; uranium monitoring; operational experience on uranium monitoring; dosimetry and radiotoxicity of inhaled radon daughters; occupational limits for inhalation of radon-222, radon-220 and their short-lived daughters; radon monitoring techniques; radon daughter dosimeters; operational experience on radon monitoring; and uranium mill tailings management

  1. Geology of the Alligator Rivers Uranium Field

    International Nuclear Information System (INIS)

    The uranium deposits of Ranger 1, Koongarra, Jabiluka One and Two, and Nabarlek are in the Alligator Rivers Uranium Field, the northeastern part of the Pine Creek Geosyncline. Lower Proterozoic metasediments, which were metamorphosed mainly to amphibolite-grade and multiply isoclinally folded at about 1800 Ma, host much of the uranium and overlie or grade into the Archaean to Lower Proterozoic granitoid Nanambu Complex. In the northeast of the Field the metasediments grade into schist and gneiss forming the outer parts of the Lower Proterozoic Nimbuwah Complex; the inner parts of this Complex contain granodioritic and tonalitic migmatite and granitoid rocks which were emplaced before the 1800 Ma event. The metasediments are intruded by pre-orogenic and post-orogenic tholeiitic dolerite, by synorogenic granite, and by later minor phonolite and dolerite dykes. All but the minor dykes are overlain with marked unconformity by Carpentarian (Middle Proterozoic) sandstone with basalt flows, which conceals older rocks over most of the southeastern half of the area. The pre-Carpentarian (pre-Middle Proterozoic) rocks are deeply weathered and lateritised and are covered extensively by Mesozoic and Cainozoic sediment. The uranium is mainly contained in the lower member of the Cahill Formation, comprising mica quartz schist, magnesite and carbonaceous schist, which is chloritised around the uranium occurrences and along faults, shears and some stratigraphic breaks. The ore zones are located in breccia. The stratabound nature of the ore suggests that it has formed partly syngenetically; however, epigenetic processes appear essential for the development of such high-grade deposits. (author)

  2. The beginning of uranium production in Estonia

    International Nuclear Information System (INIS)

    Large amounts of uranium available in the Estonian black alum (Dictyonema) shale created intense interest towards this low-grade ore in the very beginning of the atomic era. Various selective leaching and concentration technologies were tried with both roasted and native shale, at first at the Narva Pilot Plant and thereafter at the Sillamaee. Even though most of the USSR leading research and development centers participated in this effort, industrial uranium production turned out to be both technologically possible, but at the same time economically untenable at this time, just as it was the case in Sweden. (author)

  3. Geologic formation prospect of uranium Irian Jaya

    International Nuclear Information System (INIS)

    This paper was resulted from compilation of regional geologic mapping and uranium prospection in which it was considered in making exploration program. Method used was literary study of geologic information which was connected with uranium deposit occurrence. From the 26 formations identified as a formation based on physical characteristics and U grade in stream sediments and rocks, there were 2 specific formation groups which were good enough to be dealt in exploration program that is Kemblangan Group and Aifam Group. (author); 8 refs; 4 figs

  4. The uranium industry of South Africa

    International Nuclear Information System (INIS)

    This paper was originally published in 1954 and is reproduced in this centenary issue of the journal of the South African Institute of Mining and Metallurgy. South Africa's economy was (and is) based on mining. The early history of the uranium mining industry (until 1954) is discussed in detail, together with its status and economy. The first quantitative assessment of the uranium potential of the Witwatersrand goldfield was made in 1945 when it was reported that South Africa had one of the largest low-grade uranium fields in the world. The first metallurgical plants brought considerable benefit to the area. The process of uranium extraction was basically similar to that employed in the recovery of gold. It could be divided into the same three main headings: agitation, filtration and precipitation. It was predicted that the program, in full swing, would possibly consume as much as 20,000 tons of manganese ore a month, as the extraction process requires dioxide. It was for this reason that manganese recovery plants have been incorporated in the process. Other materials that were to be used in large quantities were lime, limestone, animal glue and water. Considering the increasing importance of uranium in the economy of the country, the question of secrecy was becoming a problem. At that time the demand for South African uranium was guaranteed by a ten-year agreement with the British and American authorities. 3 figs

  5. Canadian experience with uranium tailings disposal

    International Nuclear Information System (INIS)

    During the first years of uranium production in Canada uranium tailings were discharged directly into valleys or lakes near the mill. Treatment with barium chloride to precipitate radium began in 1965 at the Nordic Mine at Elliot Lake, Ontario. In the mid-60s and early 70s water quality studies indicated that discharges from uranium tailings areas were causing degradation to the upper part of the Serpent River water system. Studies into acid generation, revegetation, and leaching of radium were initiated by the mining companies and resulted in the construction of treatment plants at a number of sites. Abandoned tailings sites were revegetated. At hearings into the expansion of the Elliot Lake operations the issue of tailings management was a major item for discussion. As a result federal and provincial agencies developed guidelines for the siting and development of urnaium tailings areas prior to issuing operating licences. Western Canadian uranium producers do not have the acid generation problem of the Elliot Lake operations. The Rabbit Lake mill uses settling ponds followed by filtration. High-grade tailings from Cluff Lake are sealed in concrete and buried. Uranium producers feel that the interim criteria developed by the Atomic Energy Control Board, if adopted, would have a harmful effect on the viability of the Canadian uranium industry

  6. Uranium: myths and realities the depleted uranium

    International Nuclear Information System (INIS)

    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)

  7. Elkon - A new world class Russian uranium mine

    International Nuclear Information System (INIS)

    Full text: The uranium deposits of Elkon district are located in the south of Republic of Sakha Yakutia. Deposits contain about 6% of the world known uranium resources: 342 409 tonnes of in situ or 288 768 tonnes of recoverable RAR + Inferred resources. Most significant uranium resources of Elkon district (261 768 tonnes) were identified within five deposits of Yuzhnaya zone. The uranium grade averages 0.15%. Gold, silver and molybdenum are by-products. Principal resources are proposed to be mined by conventional underground method. Location, shape and dimensions of uranium ore bodies are primarily controlled by NW-SE oriented and steeply SW dipping faults of Mesozoic age and surrounding pyrite-carbonate-potassium feldspar alteration zones. Country rocks are Archean gneisses. Deposits are of metasomatic geological type. Principal mineralization is represented by brannerite. The Yuzhnaya zone is about 20 km long. It was explored by underground workings and drill holes. Upper limit of ore bodies is at a depth of between 200 m and 500 m. Depth persistence exceeds 2 000 m. Uranium mining enterprise Elkon was established in November 2007. It is a 100% Atomredmetzoloto subsidiary. The planned producing capacity is 5 000 m tU/year. It will perform the entire works related to uranium mining, milling, ore sorting, processing and uranium dioxide production. Technology of ore processing assumes primary radiometric sorting, thickening, sulphide flotation for gold concentrate extraction, subsequent autoclave sulphuric-acid uranium leaching from flotation tails and uranium adsorption onto resin, roasting and heap leaching for uranium from low grade ores, cyanide leaching of gold. Due to a considerable abundance of brannerite ore is classified as refractory. Elkon development include 4 main stages: feasibility study and infrastructure development (2008- 2010), mine and mill construction (2010-2015), pilot production (2013-2015), mine development and achieving full capacity

  8. DEPLETED URANIUM TECHNICAL WORK

    Science.gov (United States)

    The Depleted Uranium Technical Work is designed to convey available information and knowledge about depleted uranium to EPA Remedial Project Managers, On-Scene Coordinators, contractors, and other Agency managers involved with the remediation of sites contaminated with this mater...

  9. Ceramic Laser Materials

    Directory of Open Access Journals (Sweden)

    Guillermo Villalobos

    2012-02-01

    Full Text Available Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements.

  10. Fatigue of dental ceramics

    OpenAIRE

    Zhang, Yu; Sailer, Irena; lawn, brian

    2013-01-01

    Clinical data on survival rates reveal that all-ceramic dental prostheses are susceptible to fracture from repetitive occlusal loading. The objective of this review is to examine the underlying mechanisms of fatigue in current and future dental ceramics

  11. Governing uranium in China

    OpenAIRE

    Patton Schell, Tamara

    2014-01-01

    Nuclear power is playing an increasingly prominent role in China's long-term strategic energy calculus. In response, China is responding by producing more uranium domestically, buying more uranium on the international market, and investing heavily in overseas uranium properties. At the same time, China has been updating its nuclear regulations over the last three decades, resulting in a myriad of regulatory agencies with widely varying responsibilities related to implementing uranium regulati...

  12. 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.

  13. Ceramic art in sculpture

    OpenAIRE

    Rokavec, Eva

    2014-01-01

    Diploma seminar speaks of ceramics as a field of artistic expression and not just as pottery craft. I presented short overview of developing ceramic sculpture and its changing role. Clay inspires design and touch more than other sculpture media. It starts as early as in prehistory. Although it sometimes seems that was sculptural ceramics neglected in art history overview, it was not so in actual praxis. There is a rich tradition of ceramics in the East and also in Europe during the renaissanc...

  14. Ceramic Laser Materials

    OpenAIRE

    Guillermo Villalobos; Jasbinder Sanghera; Ishwar Aggarwal; Bryan Sadowski; Jesse Frantz; Colin Baker; Brandon Shaw; Woohong Kim

    2012-01-01

    Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG) ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers,...

  15. Uranium resources, 1983

    International Nuclear Information System (INIS)

    The specific character of uranium as energy resources, the history of development of uranium resources, the production and reserve of uranium in the world, the prospect regarding the demand and supply of uranium, Japanese activity of exploring uranium resources in foreign countries and the state of development of uranium resources in various countries are reported. The formation of uranium deposits, the classification of uranium deposits and the reserve quantity of each type are described. As the geological environment of uranium deposits, there are six types, that is, quartz medium gravel conglomerate deposit, the deposit related to the unconformity in Proterozoic era, the dissemination type magma deposit, pegmatite deposit and contact deposit in igneaus rocks and metamorphic rocks, vein deposit, sandstone type deposit and the other types of deposit. The main features of respective types are explained. The most important uranium resources in Japan are those in the Tertiary formations, and most of the found reserve belongs to this type. The geological features, the state of yield and the scale of the deposits in Ningyotoge, Tono and Kanmon Mesozoic formation are reported. Uranium minerals, the promising districts in the world, and the matters related to the exploration and mining of uranium are described. (Kako, I.)

  16. Uranium and thorium

    International Nuclear Information System (INIS)

    Present article is devoted to uranium and thorium content in fluorite. In order to obtain the comprehensive view on uranium and thorium distribution in fluorite 100 fluorite samples of various geologic deposits and ores of Kazakhstan, Uzbekistan, Tajikistan and some geologic deposits of Russia were studied. The uranium and thorium content in fluorite of geologic deposits of various mineralogical and genetic type was defined.

  17. A spectroscopic study of uranium species formed in chloride melts

    International Nuclear Information System (INIS)

    The chlorination of uranium metal or uranium oxides in chloride melts offers an acceptable process for the head-end of pyrochemical reprocessing of spent nuclear fuels. The reactions of uranium metal and ceramic uranium dioxide with chlorine and with hydrogen chloride were studied in the alkali metal chloride melts, NaCl-KCl at 973K, NaCl-CsCl between 873 and 923K and LiCl-KCl at 873K. The uranium species formed therein were characterized from their electronic absorption spectra measured in situ. The kinetic parameters of the reactions depend on melt composition, temperature and chlorinating agent used. The reaction of uranium dioxide with oxygen in the presence of alkali metal chlorides results in the formation of alkali metal uranates. A spectroscopic study, between 723 and 973K, on their formation and their solutions was undertaken in LiCl, LiCl-KCl eutectic and NaCl-CsCl eutectic melts. The dissolution of uranium dioxide in LiCl-KCl eutectic at 923K containing added aluminium trichloride in the presence of oxygen has also been investigated. In this case, the reaction leads to the formation of uranyl chloride species. (author)

  18. Contribution to the geochemical knowledge of the uranium-radium and thorium families in the southern Vosges. Applications of some results in the prospecting of uranium deposits

    International Nuclear Information System (INIS)

    This work's aim is to lead to a more accurate knowledge of the geochemistry of the Uranium-Radium and Thorium families in the Southern Vosges and to apply some of the results to the prospecting of uraniferous deposits: It has been showed: a bond between Calcium-Magnesium and Uranium-Thorium in the calco-alkaline granites. The host minerals of Uranium and Thorium are hornblende, biotite, titanite and epidote. a concentration of Uranium, at present time with secular disequilibrium in a thermal zone where the satellite mineralizations form an epithermal paragenesis. a disequilibrium of the Uranium-Radium family in the supergene minerals of the lead (phosphate and vanadate) showing the present circulations of Uranium. a bond between the radon grade of the spring waters and Uranium-Radium of the rocks. Such a relation allow to realize a prospecting method based on the determination of radioactive gases from the cold spring-waters of a common country. (author)

  19. Towards a Model for Albitite-Type Uranium

    OpenAIRE

    Andy Wilde

    2013-01-01

    Albitite-type uranium deposits are widely distributed, usually of low grade (<1% U3O8), but are often large and collectively contain over 1 million tonnes of U3O8. Uranium is hosted in a wide range of metamorphic lithologies, whose only common characteristic is that they have been extensively mylonitised. Ore minerals are disseminated and rarely in megascopic veins, within and adjacent to albitised mylonites. Grain size is uniformly fine, generally less than 50 microns. Scanning electr...

  20. Uranium production cycle: Argentine situation

    International Nuclear Information System (INIS)

    Full text: In Argentina, nuclear power plants at Atucha and Embalse are in operation with very high plant load factors. Atucha II is under construction with the expected start-up in 2012. The long term nuclear power plan of Argentina envisages additional seven units in the next 25 years. It is estimated that the cumulative uranium requirements for these nuclear power plants will be about 30000 tU. However the estimated uranium reserves of Argentina at present in different categories is only approximately 15000 tU. Sierra Pintada mine, south west of the Mendoza province, was in production from 1975 to 1995 and was kept in stand-by from 1995. Quartz, feldspar, calcite, and kaolinite are the most abundant minerals in the ore. The rock is formed by moderately well-sorted grains of quartz, feldspar, and rock fragments, all cemented by calcite with minor clay replacement. The mine is an open pit and at 0.025%U cut off about 6500 tU reserves were estimated. Average grade is 0.076% U. The barren - ore rock ratio is 10:1 and barren benches are 10m and ore benches 2.5 m in height. So far 13400000 m3 of barren rock, 376000 t low grade ore and 2500000t plant feed ore has been mined out. The Sierra Pintada mine is expected to restart operations by 2010. The major problems in restarting this mine are the mining laws, community issues and apprehensions of the local tourism and wine industries. The paper will discuss the mining law in Argentina vis-a-vis the uranium situation and exploration programme for the the next years. (author)

  1. The South Greenland uranium exploration programme

    International Nuclear Information System (INIS)

    This is the final report of the reconnaissance phase of the SYDURAN Project which was initiated in 1st. December 1978 to outline areas of increased uranium potential where more detailed prospection would be warranted. Districts and smaller zones in South Greenland which have the potential for containing economically exploitable uranium occurrences were defined using airborne gamma-spectroscopic, reconnaissance geochemical and geological methods. Other districts and areas have been shown to have no uranium potential and can be eliminated. The three promising districts are: 1. a 2000 square kilometre sub-circular district surrounding Ilimaussaq complex in which there are small high grade pitchblende occurences in faults and fractures in the surrounding granite. 2. the eastern area of the Motzfeldt Centre where large parts of the centre is mineralised and may give rise to exploitable, large tonnage, low grade uranium ore with associated niobium and rare earth elements in extractable quantities. 3. uraniferous rich districts or zones associated with the migmatitic supracrustal units in the area between Kap Farvel and Lindenows Fjord. The areas which were eliminated from having any uranium potential include: the Ketilidian supracrustal unit. the Nunarssuit alkaline complex. The uranium mineralisation in South Greenland is confined to two Proterozoic episodes: a) a late phase of granitisation and migmatisation with the formation of disseminated uraninite in the Migmatite Complex in the south of the project area between 1700-1800 m.y. and, b) hydrothermal activity associated with Gardar magmatic events between 1090-1170 m.y. in the central Granite Zone. Future work should be directed towards the definition and location of drilling targets. (EG)

  2. U.S. forms uranium enrichment corporation

    International Nuclear Information System (INIS)

    After almost 40 years of operation, the federal government is withdrawing from the uranium enrichment business. On July 1, the Department of Energy turned over to a new government-owned entity--the US Enrichment Corp. (USEC)--both the DOE enrichment plants at Paducah, Ky., and Portsmouth, Ohio, and domestic and international marketing of enriched uranium from them. Pushed by the inability of DOE's enrichment operations to meet foreign competition, Congress established USEC under the National Energy Policy Act of 1992, envisioning the new corporation as the first step to full privatization. With gross revenues of $1.5 billion in fiscal 1992, USEC would rank 275th on the Fortune 500 list of top US companies. USEC will lease from DOE the Paducah and Portsmouth facilities, built in the early 1950s, which use the gaseous diffusion process for uranium enrichment. USEC's stock is held by the US Treasury, to which it will pay annual dividends. Martin Marietta Energy Systems, which has operated Paducah since 1984 and Portsmouth since 1986 for DOE, will continue to operate both plants for USEC. Closing one of the two facilities will be studied, especially in light of a 40% world surplus of capacity over demand. USEC also will consider other nuclear-fuel-related ventures. USEC will produce only low-enriched uranium, not weapons-grade material. Indeed, USEC will implement a contract now being completed under which the US will purchase weapons-grade uranium from dismantled Russian nuclear weapons and convert it into low-enriched uranium for power reactor fuel

  3. Thin film ceramic thermocouples

    Science.gov (United States)

    Gregory, Otto (Inventor); Fralick, Gustave (Inventor); Wrbanek, John (Inventor); You, Tao (Inventor)

    2011-01-01

    A thin film ceramic thermocouple (10) having two ceramic thermocouple (12, 14) that are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma. Since each element is prepared under different plasma conditions, they have different electrical conductivity and different charge carrier concentration. The thin film thermocouple (10) can be transparent. A versatile ceramic sensor system having an RTD heat flux sensor can be combined with a thermocouple and a strain sensor to yield a multifunctional ceramic sensor array. The transparent ceramic temperature sensor that could ultimately be used for calibration of optical sensors.

  4. Research on forecasting models of cost of natural uranium production

    International Nuclear Information System (INIS)

    The forecasting model is established for the product cost of long term or short term on the basis of the history data of natural uranium, focusing on the relationship between the factors such as the ore grade, excavate rate, digging depth and ore properties, and the product cost of natural uranium. Another forecasting model is founded for sub-product cost using symbolic statistical linear regression method. The models described above are applied to the product cost of some uranium mine corporation. The method is easy, practical and reliable with reference value. (authors)

  5. Machinability evaluation of machinable ceramics with fuzzy theory

    Institute of Scientific and Technical Information of China (English)

    YU Ai-bing; ZHONG Li-jun; TAN Ye-fa

    2005-01-01

    The property parameters and machining output parameters were selected for machinability evaluation of machinable ceramics. Based on fuzzy evaluation theory, two-stage fuzzy evaluation approach was applied to consider these parameters. Two-stage fuzzy comprehensive evaluation model was proposed to evaluate machinability of machinable ceramic materials. Ce-ZrO2/CePO4 composites were fabricated and machined for evaluation of machinable ceramics. Material removal rates and specific normal grinding forces were measured. The parameters concerned with machinability were selected as alternative set. Five grades were chosen for the machinability evaluation of machnable ceramics. Machinability grades of machinable ceramics were determined through fuzzy operation. Ductile marks are observed on Ce-ZrO2/CePO4 machined surface. Five prepared Ce-ZrO2/CePO4 composites are classified as three machinability grades according to the fuzzy comprehensive evaluation results. The machinability grades of Ce-ZrO2/CePO4 composites are concerned with CePO4 content.

  6. Depending on scientific and technological progress to prospect for superlarge uranium deposits. Across-century target for uranium resources exploration work in China

    International Nuclear Information System (INIS)

    After over 30 years' development, uranium resources exploration work in China has resulted in the discovery of more than 10 economic types of uranium deposits in 23 provinces (regions) of the whole country and large quantities of uranium reserves have been submitted which guarantee the development of nuclear industry in China. However, characteristics such as smaller size of deposits and ore bodies, and lower ore grade of discovered China's uranium deposits have brought about a series of problems on how to economically exploit and utilize these uranium resources. To prospect for superlarge uranium deposits is a guarantee of making uranium resources essentially meet the demand for the long-term development of nuclear industry in China, and is an important way of improving economic benefits in mining China's uranium resources. It is an important mark for uranium geological exploration work to go up a new step as well. China exhibits the geological environment in which various types of superlarge uranium deposits can be formed. Having the financial support from the state to uranium resources exploration work, having professional uranium exploration teams well-experienced in ore prospecting, having modernized uranium exploration techniques and equipment and also having foreign experience in prospecting for superlarge uranium deposits as reference, it is entirely possible to find out superlarge uranium deposits in China at the end of this century and at the beginning of next century. In order to realize the objective, the most important prerequisite is that research work on metallogenetic geological theory and exploration techniques and prospecting methodology for superlarge uranium deposits must be strengthened, and technical quality of the geological teams must be improved. Within this century, prospect targets should be selected and located accurately to carry out the emphatic breakthrough in exploration strategy

  7. 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....

  8. Modelling a uranium ore bioleaching process

    International Nuclear Information System (INIS)

    A dynamic simulation model for the bioleaching of uranium ore in a stope leaching process has been developed. The model incorporates design and operating conditions, reaction kinetics enhanced by Thiobacillus ferroxidans present in the leaching solution and transport properties. Model predictions agree well with experimental data with an average deviation of about ± 3%. The model is sensitive to small errors in the estimates of fragment size and ore grade. Because accurate estimates are difficult to obtain a parameter estimation approach was developed to update the value of fragment size and ore grade using on-line plant information

  9. Impact of recovered uranium cycle on the natural uranium production cycle and the environment

    International Nuclear Information System (INIS)

    The requirements by which future reactor and fuel cycle concepts must be judged are following: - properly utilize natural resources and national capabilities; - maximize the economic benefits; - effectively demonstrate the safety of fuel cycle facilities, and gain government and public approval for the enterprise; - satisfy national and international policies and goals; - contribute to sustainable energy supply. The ability to combine these five requirements ensures the success of the best options. Fuel utilization in thermal reactors can be improved in three ways: - lower the tails assay in the depleted stream of enrichment plants; - utilization of higher burnup fuel; - recycle plutonium. Recovered Uranium (RU) Cycle is a way to improve Slightly Enriched Uranium resulted from LWR spent fuel reprocessing which has 0.9-1.2% 235 U (dependent of the fuel history: reprocessing, burn up, reactor type) comparatively with 0.72% 235 U in natural Uranium. An international collaboration between Korea Atomic Energy Research Institute (KAERI), Atomic Energy of Canada Limited (AECL) and British Nuclear Fuel plc (BNFL) to use RU was developed. Since 1991, KAERI and AECL have introduced the Canadian Flexible (CANFLEX) fuel concept. A very attractive alternative to use RU in CANDU Reactors appears. Theoretically the quantity of 25,000 t (Europe and Japan) of RU would provide sufficient fuel for 500 CANDU reactor years of operation, knowing that the annual refueling requirement for a RU fuel burnup 13 MWd/KgU is around 50 t/y in comparison with 85 t/y for Natural Uranium (NU). Hereby, it is not necessary to mine about 42,500 t grade NU. In conclusion Recovered Uranium fuel cycle can be a very good option for the future of nuclear power in Romania. Moreover, waste resulted from uranium mining, waste resulted from uranium grade obtaining will disappear and financial costs, zones with nuclear activities and population exposed to irradiation will decrease. Also, the costs for fresh

  10. Development of sprayed ceramic seal systems for turbine gas path sealing

    Science.gov (United States)

    Bill, R. C.; Shiembob, L. T.; Stewart, O. L.

    1978-01-01

    A ceramic seal system is reported that employs plasma-sprayed graded metal/ceramic yttria stabilized zirconium oxide (YSZ). The performance characteristics of several YSZ configurations were determined through rig testing for thermal shock resistance, abradability, and erosion resistance. Results indicate that this type of sealing system offers the potential to meet operating requirements of future gas turbine engines.

  11. 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.

  12. Mechanical and biological properties of the micro-/nano-grain functionally graded hydroxyapatite bioceramics for bone tissue engineering.

    Science.gov (United States)

    Zhou, Changchun; Deng, Congying; Chen, Xuening; Zhao, Xiufen; Chen, Ying; Fan, Yujiang; Zhang, Xingdong

    2015-08-01

    Functionally graded materials (FGM) open the promising approach for bone tissue repair. In this study, a novel functionally graded hydroxyapatite (HA) bioceramic with micrograin and nanograin structure was fabricated. Its mechanical properties were tailored by composition of micrograin and nanograin. The dynamic mechanical analysis (DMA) indicated that the graded HA ceramics had similar mechanical property compared to natural bones. Their cytocompatibility was evaluated via fluorescent microscopy and MTT colorimetric assay. The viability and proliferation of rabbit bone marrow mesenchymal stem cells (BMSCs) on ceramics indicated that this functionally graded HA ceramic had better cytocompatibility than conventional HA ceramic. This study demonstrated that functionally graded HA ceramics create suitable structures to satisfy both the mechanical and biological requirements of bone tissues.

  13. Characteristics of uranium districts of the Russian Federation

    International Nuclear Information System (INIS)

    Uranium deposits are discovered in 15 ore districts of the Russian Federation. They are subdivided into four groups: Streltsovsky district with existing production centre, Stavropolsky district with depleted deposits, three prospective districts and ten reserve districts. The overview of new data on these districts is presented. Streltsovsky district with Priargunsky Production Centre include 19 molybdenum-uranium deposits of structure-bound volcanic type in caldera. The main activities in Stavropolsky district with two depleted uranium deposits are connected with restoration works and wastes rehabilitation. Except Streltsovsky district there are no more deposits in the Russian Federation prepared for uranium production. At the same time some uranium deposits of Vitimsky, Zauralsky, and West-Siberian districts are prospective for new development of production centres. They belong to the sandstone type, related to paleovalley or basal channel, and are suitable for ISL operation. The deposits of the other districts are considered to be reserve and considered unprofitable for uranium production at present and in the nearest future. The biggest of them is Aldansky district with gold-uranium deposits in potassium metasomatites in areas of Mesozoic activation of Archean cratons. Central Transbaikalsky, Yeniseisky, Yergeninsky, Onezhsky, Ladozhsky, Bureinsky, Khankaisky, Volgo-Uralsky reserve districts include mainly small-size deposits of vein, volcanic, surficial and metasomatite types with low uranium grades. (author)

  14. [Detection of trace uranium in air with field spectrometry].

    Science.gov (United States)

    Yang, Ya-Xin; Xiao, Sai-Jin; Liu, Qing-Cheng; Huang, Long-Zhu; Peng, Dao-Feng; Zheng, Yong-Ming

    2012-07-01

    As a natural radioactive element, uranium and its compounds exist as aerosol and transfer in air. In gas phase, uranium can cause various kinds of radioactive damage to human body. The change in its concentration in a local area is related to the exploration and utilization of nuclear energy. Therefore, the development of field method for rapid uranium detection in air sample is very important. In this contribution, the air samples over uranium ores collected by a general pump was absorbed with 2.0 mol x L(-1) nitrate and then reacted with solid reagent kit. When the reaction between trace uranium and chromogenic reagent was finished, the homemade portable photometer was used to measure the absorbance. The results showed that the concentration of uranium in air samples over low grade uranium ores can be successfully determined by the present method and the values agree with that obtained by ICP-MS. The RSD measured by the new method was 1.72%. The application of the new field spectrometry in discriminating uranium ores from other ores has the potential advantages of easy operation, cost-saving and high accuracy. PMID:23016358

  15. International training course on uranium exploration

    International Nuclear Information System (INIS)

    Full text: As part of its Technical Assistance Programme for developing countries, the IAEA has conducted a series of training courses in prospecting for nuclear raw materials for example, in 1974 a regional course on uranium and thorium prospecting was held in India, and an interregional training course on uranium geochemical prospecting methods was held in Austria in 1975. In September 1977, another interregional training course on uranium geochemical prospecting methods was held at Skofja Loka, Slovenia, Yugoslavia. Twenty-four delegates from Afghanistan, Algeria, Argentina, Bolivia, Chile, Colombia, Czechoslovakia, India, Indonesia, Malaysia, Philippines, Portugal, Sri Lanka, Turkey, Venezuela and Yugoslavia participated in the four-week training course. The Federal Republic of Yugoslavia acted as host for the course. The Skofja Loka area was selected because it contains sedimentary rocks with known uranium mineralization, and presented ideal conditions (soil, drainage and topography) for Uranium geochemical surveys. In addition, the participants could benefit from a technical visit to a very interesting type of uranium mineralization near the town of Gorenje Vaz. Several well-known geologists, such as Dr. A. Grimbert (France) and Prof. Ian Nichol (Canada) were present as guest lecturers. In the first week the lectures dealt with the basic concepts of geochemical exploration for uranium, as well as preparing the participants for the field work. In addition to specific topics on geochemistry and uranium behaviour in the natural environment, the lectures also covered other topics of interest, such as world uranium resources and demand, types of uranium deposits and technical advances in exploration equipment. A visit to the Zirovski Vrh uranium mine was made, where the participants saw different techniques for mining ore bodies with complex structure and rapid change in grade concentration. At the end of the mine tour, there was a lengthy discussion of

  16. Uranium enrichment. Principles

    International Nuclear Information System (INIS)

    Uranium enrichment industry is a more than 60 years old history and has developed without practically no cost, efficiency or profit constraints. However, remarkable improvements have been accomplished since the Second World War and have led to the development of various competing processes which reflect the diversity of uranium compositions and of uranium needs. Content: 1 - general considerations: uranium isotopes, problem of uranium enrichment, first realizations (USA, Russia, Europe, Asia, other countries), present day situation, future needs and market evolution; 2 - principles of isotopic separation: processes classification (high or low enrichment), low elementary enrichment processes, equilibrium time, cascade star-up and monitoring, multi-isotopes case, uranium reprocessing; 3 - enrichment and proliferation. (J.S.)

  17. Uses of depleted uranium

    International Nuclear Information System (INIS)

    The depleted uranium is that in which percentage of uranium-235 fission executable is less than 0.2% or 0.3%. It is usually caused by the process of reprocessing the nuclear fuel burning, and also mixed with some other radioactive elements such as uranium 236, 238 and plutonium 239. The good features of the depleted uranium are its high density, low price and easily mined. So, the specifications for depleted uranium make it one of the best materials in case you need to have objects small in size, but quite heavy regarding its size. Uses of deplet ed uranium were relatively increased in domestic industrial uses as well as some uses in nuclear industry in the last few years. So it has increased uses in many areas of military and peaceful means such as: in balancing the giant air crafts, ships and missiles and in the manufacture of some types of concrete with severe hardness. (author)

  18. Uranium Newsletter. No. 1

    International Nuclear Information System (INIS)

    The new Uranium Newsletter is presented as an IAEA annual newsletter. The organization of the IAEA and its involvement with uranium since its founding in 1957 is described. The ''Red Book'' (Uranium Resources, Production and Demand) is mentioned. The Technical Assistance Programme of the IAEA in this field is also briefly mentioned. The contents also include information on the following meetings: The Technical Committee Meeting on Uranium Deposits in Magmatic and Metamorphic Rocks, Advisory Group Meeting on the Use of Airborne Radiometric Data, and the Technical Committee Meeting on Metallogenesis. Recent publications are listed. Current research contracts in uranium exploration are mentioned. IAEA publications on uranium (in press) are listed also. Country reports from the following countries are included: Australia, Brazil, Canada, China (People's Republic of), Denmark, Finland, Germany (Federal Republic of), Malaysia, Philippines, Portugal, South Africa (Republic of), Spain, Syrian Arab Republic, United Kingdom, United States of America, Zambia, and Greece. There is also a report from the Commission of European Communities

  19. Geochemical exploration for uranium

    International Nuclear Information System (INIS)

    This Technical Report is designed mainly to introduce the methods and techniques of uranium geochemical exploration to exploration geologists who may not have had experience with geochemical exploration methods in their uranium programmes. The methods presented have been widely used in the uranium exploration industry for more than two decades. The intention has not been to produce an exhaustive, detailed manual, although detailed instructions are given for a field and laboratory data recording scheme and a satisfactory analytical method for the geochemical determination of uranium. Rather, the intention has been to introduce the concepts and methods of uranium exploration geochemistry in sufficient detail to guide the user in their effective use. Readers are advised to consult general references on geochemical exploration to increase their understanding of geochemical techniques for uranium

  20. The Future Contribution of Unconventional Sources of Natural Uranium to Nuclear Fuel Supply. Contribution future des sources conventionnelles d'uranium naturel à l'approvisionnement en combustible nucléaire

    OpenAIRE

    Boyd B. W.

    2006-01-01

    From what we know about the distribution of uranium in the earth's crust, we can get an indication of how much uranium is likely to occur at concentrations higher than 300 ppm. Although only part of this material is likely to be discovered and brought to production, the amounts are great enough to make it unlikely that much uranium from lower grade deposits will be mined in the next 40 or so years except in special cases. In some circumstances, low grade uranium can be recovered as a by-produ...

  1. Ceramic tamper-revealing seals

    Science.gov (United States)

    Kupperman, David S.; Raptis, Apostolos C.; Sheen, Shuh-Haw

    1992-01-01

    A flexible metal or ceramic cable with composite ceramic ends, or a u-shaped ceramic connecting element attached to a binding element plate or block cast from alumina or zirconium, and connected to the connecting element by shrink fitting.

  2. Analyses of fine paste ceramics

    International Nuclear Information System (INIS)

    Four chapters are included: history of Brookhaven fine paste ceramics project, chemical and mathematical procedures employed in Mayan fine paste ceramics project, and compositional and archaeological perspectives on the Mayan fine paste ceramics

  3. Analyses of fine paste ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Sabloff, J A [ed.

    1980-01-01

    Four chapters are included: history of Brookhaven fine paste ceramics project, chemical and mathematical procedures employed in Mayan fine paste ceramics project, and compositional and archaeological perspectives on the Mayan fine paste ceramics. (DLC)

  4. Uranium industry annual, 1988

    International Nuclear Information System (INIS)

    This report presents data on US uranium raw materials and marketing activities of the domestic uranium industry. It contains aggregated data reported by US companies on the ''Uranium Industry Annual Survey'' (1988), Form EIA-858, and historical data from prior data collections and other pertinent sources. The report was prepared by the Energy Information Administration (EIA), the independent agency for data collection and analysis with the US Department of Energy

  5. Simulating distinguish enriched uranium from depleted uranium by activation method

    International Nuclear Information System (INIS)

    Detecting uranium material is an important work in arms control Active detection is an efficient method for uranium material. The paper focuses on the feasibility that can distinguish the enriched uranium and the depleted uranium by MCNP program. It can distinguish the enriched uranium and the depleted uranium by the curve of relationship between fission rate of uranium material and thickness of moderator.Advantages of 252Cf and 14 MeV neutron sources are discussed in detecting uranium material through calculation. The results show that 252Cf neutron source is better than 14 MeV one. Delayed neutrons are more easily detected than delayed gamma ray at measurement aspect. (authors)

  6. Uranium in Precambrian granitic rocks of the St. Francois Mountains, southeastern Missouri, with comments on uranium resource potential

    International Nuclear Information System (INIS)

    Red granites of the St. Francois Mountains are highly radioactive and contain 4 to 34 ppM uranium. The most radioactive is the Graniteville Granite which contains an average of 16.9 ppM U and 42.6 ppM Th. The Butler Hill and Breadtray Granites also contain anomalous amounts, averaging 6.2 and 5.6 ppM U and 23.5 and 20.5 ppM Th respectively. Other Precambrian granitic rocks have normal concentrations of U and Th. Fission track ''maps'' indicate that high concentrations of uranium are associated with magnetite in the red granites; this uranium is presumed to be readily leachable by hydrothermal or supergene solutions. No uranium minerals or ore grade concentrations of uranium were observed in or near the granites, but there are conceptual reasons for the possible existence of uranium deposits in intragranitic veins and onlapping Cambrian-Ordovician sedimentary rocks. Although the red granites constitute a good potential source of uranium, there is not much evidence for uranium having been mobilized. Identification of features such as lamprophyre dikes and ''episyenite'' alteration, or sedimentary rocks containing reductants, would be of value for exploration and would permit more favorable resource appraisal

  7. Speciation of uranium in La2Zr2O7 pyrochlore by TRPLS

    Science.gov (United States)

    Mohapatra, M.; Rajeswari, B.; Hon, N. S.; Kadam, R. M.; Natarajan, V.

    2015-06-01

    We discuss the speciation of uranium in lanthanum zirconate (La2Zr2O7 =LZO) pyrochlore ceramic prepared via a gel-combustion route. Uranium concentration in the pyrochlore was optimized to 2 mol%. XRD and SEM experiments were carried out to assess the phase and homogeneity of the prepared samples. Time resolved photoluminescence (TRPLS) investigations were carried out for understanding the species stabilized in the pyrochlore host. It was observed that, uranium exists as uranate ion (UO66-) in the zirconate host where it replaces the `Zr' ions at its regular site with surrounding defect centers created for charge compensation.

  8. Internal dosimetry for uranium fuel manufacture at BNFL

    International Nuclear Information System (INIS)

    At its Springfields Works, near Preston, UK BNFL manufactures uranium fuels and fuel intermediates, in a range of chemical and metallurgical processes. Uranium ore concentrate is converted to uranium metal for the Magnox reactors, uranium hexafluoride (UF6) to uranium dioxide (UO2) for AGR and other oxide reactors, and various intermediate products are produced to meet customer requirements. Thus, uranium compounds with biological retention periods ranging from days (UF6) to years (UO2) are handled on multi-hundred, or thousand, tonne per year scales. Control and minimisation of workforce exposure is exercised primarily by engineered methods (e.g. total enclosures and high integrity plant), backed up by use of respiratory and other protective equipment. A high profile is given to good standards of housekeeping. Assessment of intake is by methods approved by HSE (NII) in the Approved Laboratory Statement on internal dosimetry. The principal method is assessment by use of continuous air sampling combined with occupancy. This is back up by routine personal air sampling (PAS) in selected relevant areas in which ceramic UO2 is handled. Further assurance is provided by programmed PAS in other areas and by systematic, and routine, urinalysis and whole-body monitoring of all relevant members of the workforce. The results of the above are presented in detail. (Author)

  9. Continuous Fiber Ceramic Composites

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-09-01

    Fiber-reinforced ceramic composites demonstrate the high-temperature stability of ceramics--with an increased fracture toughness resulting from the fiber reinforcement of the composite. The material optimization performed under the continuous fiber ceramic composites (CFCC) included a series of systematic optimizations. The overall goals were to define the processing window, to increase the robustinous of the process, to increase process yield while reducing costs, and to define the complexity of parts that could be fabricated.

  10. CHEMICAL TOXICITY OF URANIUM

    OpenAIRE

    2007-01-01

    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

  11. 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

  12. International trade in uranium

    International Nuclear Information System (INIS)

    Two reports are presented; one has been prepared by the Uranium Institute and is submitted by the United Kingdom delegation, the other by the United States delegation. The report of the Uranium Institute deals with the influence of the government on international trade in uranium. This influence becomes apparent predominantly by export and import restrictions, as well as by price controls. The contribution submitted by the United States is a uranium market trend analysis, with pricing methods and contracting modes as well as the effect of government policies being investigated in the light of recent developments

  13. 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.

  14. Heating uranium alloy billets

    International Nuclear Information System (INIS)

    Data were obtained for the surface heat transfer coefficient of uranium and the alloys of uranium-0.75 wt percent titanium, uranium-6 wt percent niobium, and uranium-7.5 wt percent niobium-2.5 wt percent zirconium. Samples were heated to 8500C in both a molten salt bath and an argon-purged air furnace, then the samples were cooled in air. Surface heat transfer coefficients were calculated from the experimental data for both heating and cooling of the metals. 4 fig, 4 tables

  15. Measuring Fracture Times Of Ceramics

    Science.gov (United States)

    Shlichta, Paul J.; Bister, Leo; Bickler, Donald G.

    1989-01-01

    Electrical measurements complement or replace fast cinematography. Electronic system measures microsecond time intervals between impacts of projectiles on ceramic tiles and fracture tiles. Used in research on ceramics and ceramic-based composite materials such as armor. Hardness and low density of ceramics enable them to disintegrate projectiles more efficiently than metals. Projectile approaches ceramic tile specimen. Penetrating foil squares of triggering device activate display and recording instruments. As ceramic and resistive film break oscilloscope plots increase in electrical resistance of film.

  16. Characteristics of basement granitoids and their role on uranium mineralisation in and around southwestern margin of Cuddapah Basin, Andhra Pradesh

    International Nuclear Information System (INIS)

    Different types of uranium mineralisation in the environs of Cuddapah Basin show temporal and spatial association with uraniferous basement granitoids (Closepet Equivalent) exposed in its southern and southwestern margin. Geochemical studies of these granitoids show that these are generally peraluminous and strongly differentiated with uranium concentration from 10 to 90 ppm. Uranium mineralisation (in terms of grade and thickness) in the granite-hosted, fracture- controlled type and in the Cuddapah sediments is pronounced in areas where basement rocks have more volume of these strongly differentiated uraniferous granitoids. In contrast, uranium mineralisation is of low grade and thickness where basement is represented by Peninsular gneisses. (author)

  17. Defect production in ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Zinkle, S.J. [Oak Ridge National Lab., TN (United States); Kinoshita, C. [Kyushu Univ. (Japan)

    1997-08-01

    A review is given of several important defect production and accumulation parameters for irradiated ceramics. Materials covered in this review include alumina, magnesia, spinel silicon carbide, silicon nitride, aluminum nitride and diamond. Whereas threshold displacement energies for many ceramics are known within a reasonable level of uncertainty (with notable exceptions being AIN and Si{sub 3}N{sub 4}), relatively little information exists on the equally important parameters of surviving defect fraction (defect production efficiency) and point defect migration energies for most ceramics. Very little fundamental displacement damage information is available for nitride ceramics. The role of subthreshold irradiation on defect migration and microstructural evolution is also briefly discussed.

  18. Voltametric determination of O:U relation in uranium oxide

    International Nuclear Information System (INIS)

    Uranium oxide samples are dissolved in hot concentrated H3PO4 - H2SO4 mixture and the solution diluted with 1M H2SO4. One aliquot of such solution (A) is used to record the first voltamogram which gives the U(VI) content. To a second aliquot HNO3 and H2O2 is added to oxidise uranium to the hexavalent state (B) and the second voltamogram is recorded from 0.0 to 0.4 V X SCE. The O:U ratio in the original sample is calculated by the expression: O/U = 2.000 + [U (VI) soln.A/% U(VI) soln. B]. The method provides an accurate means for determining O to U ratios in high-purity uranium dioxide, fuel pellets and a variety of oxides prepared for developmental work on ceramic fuel materials. (author)

  19. Hot isostatic pressing of ceramic waste from spent nuclear fuel

    International Nuclear Information System (INIS)

    Argonne National Laboratory has developed a process to immobilize waste salt containing fission products, uranium, and transuranic elements as chlorides in a glass-bonded ceramic waste form. This salt was generated in the electrorefining operation used in electrometallurgical treatment of spent Experimental Breeder Reactor-II fuel. The ceramic waste process culminated with a hot isostatic pressing operation. This paper reviews the installation and operation of a hot isostatic press in a radioactive environment. Processing conditions for the hot isostatic press are presented for non-irradiated material and irradiated material. Sufficient testing was performed to demonstrate that a hot isostatic press could be used as the final step of the processing of ceramic waste for the electrometallurgical spent fuel treatment process

  20. Improved polyphase ceramic for high-level defense waste

    International Nuclear Information System (INIS)

    Modifications of the chemical formulation and processing of the Synroc-D polyphase ceramic for defense waste have been studied to provide greater flexibility with respect to compositional variations in the waste and to improve leach resistance. It has been demonstrated that by applying only that amount of reduction to the waste required to produce uranium in the 4+ state and by using lower consolidation temperatures, an improved ceramic can be formed. The resulting ceramic consolidated at 10400C and 10,000 psi maintanis the Synroc-D zirconolite, perovskite and nepheline phases; however, the two Synroc-D spinel phases are replaced with a single magnetite-type spinel and two additional radiophases, magnetoplumbite, and a cubic murataite-type phase. This modified phase assemblage provides crystalline ost sites for all radionuclides and trace elements in SRP waste, minmizes amorphoous intergranular material, and shows superior leach resistance

  1. Optimization of ceramic strength using elastic gradients.

    Science.gov (United States)

    Zhang, Yu; Ma, Li

    2009-05-01

    We present a new concept for strengthening ceamics by utilizing a graded structure with a low elastic modulus at both top and bottom surfaces sandwiching a high-modulus interior. Closed-form equations have been developed for stress analysis of simply supported graded sandwich beams subject to transverse center loads. Theory predicts that suitable modulus gradients at the ceramic surface can effectively reduce and spread the maximum bending stress from the surface into the interior. The magnitude of such stress dissipation is governed by the thickness ratio of the beam to the graded layers. We test our concept by infiltrating both top and bottom surfaces of a strong class of zirconia ceramic with an in-house prepared glass of similar coefficient of thermal expansion and Poisson's ratio to zirconia, producing a controlled modulus gradient at the surface without significant long-range residual stresses. The resultant graded glass/zirconia/glass composite exhibits significantly higher load-bearing capacity than homogeneous zirconia. PMID:20161019

  2. Uranium industry annual 1993

    International Nuclear Information System (INIS)

    Uranium production in the United States has declined dramatically from a peak of 43.7 million pounds U3O8 (16.8 thousand metric tons uranium (U)) in 1980 to 3.1 million pounds U3O8 (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 U3O8 (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

  3. 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.

  4. Standard specification for sintered gadolinium oxide-uranium dioxide pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This specification is for finished sintered gadolinium oxide-uranium dioxide pellets for use in light-water reactors. It applies to gadolinium oxide-uranium dioxide pellets containing uranium of any 235U concentration and any concentration of gadolinium oxide. 1.2 This specification recognizes the presence of reprocessed uranium in the fuel cycle and consequently defines isotopic limits for gadolinium oxide-uranium dioxide pellets made from commercial grade UO2. Such commercial grade UO2 is defined so that, regarding fuel design and manufacture, the product is essentially equivalent to that made from unirradiated uranium. UO2 falling outside these limits cannot necessarily be regarded as equivalent and may thus need special provisions at the fuel fabrication plant or in the fuel design. 1.3 This specification does not include (1) provisions for preventing criticality accidents or (2) requirements for health and safety. Observance of this specification does not relieve the user of the obligation to be aw...

  5. Evaluation of selected neutralizing agents for the treatment of uranium tailings leachates. Laboratory progress report

    International Nuclear Information System (INIS)

    Laboratory experiments were conducted to evaluate the performance of selected neutralizing agents for the treatment of uranium tailings solutions. Highly acidic tailings solutions (pH3) reagent grade; Calcium hydroxide [Ca(OH)2] reagent grade; Magnesium oxide (MgO) reagent grade; Sodium carbonate (Na2CO3) reagent grade; and Sodium hydroxide (NaOH) reagent grade. Evaluation of the effectiveness for the treatment of uranium tailings solutions for the selected neutralizing agents under controlled laboratory conditions was based on three criteria. The criteria are: (1) treated effluent water quality, (2) neutralized sludge handling and hydraulic properties, and (3) reagent costs and acid neutralizing efficiency. On the basis of these limited laboratory results calcium hydroxide or its dehydrated form CaO (lime) appears to be the most effective option for treatment of uranium tailings solutions

  6. The prospects for Canadian uranium

    International Nuclear Information System (INIS)

    The 1980s have seen a decline in markets for uranium concentrate, largely as a result of falling estimates for reactor fuel requirements and rising inventories. Spot market prices fell to $44 in September 1982, but have since risen back to $60. World production also fell in 1982 and is not expected to increase significantly before 1990. Some opportunities exist for Canadian producers with new low-cost deposits to replace high-cost producers in Canada and other countries, particularly the United States. There will be strong competition between Canadian producers as well as from Australia. Australia's reserves are somewhat larger than Canada's, although the reported ore grades tend to be lower than those of Saskatchewan

  7. Ceramic Technology Project

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    The Ceramic Technology Project was developed by the USDOE Office of Transportation Systems (OTS) in Conservation and Renewable Energy. This project, part of the OTS's Materials Development Program, was developed to meet the ceramic technology requirements of the OTS's automotive technology programs. Significant accomplishments in fabricating ceramic components for the USDOE and NASA advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. These programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. A five-year project plan was developed with extensive input from private industry. In July 1990 the original plan was updated through the estimated completion of development in 1993. The objective is to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on the structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. To facilitate the rapid transfer of this technology to US industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities.

  8. Uranium recovery from phosphates in Romania

    International Nuclear Information System (INIS)

    The history of laboratory and pilot-scale research work carried out in Romania is reviewed. Based on this work, three industrial-scale uranium recovery units have been built adjacent to the existing plants that produce phosphoric acid for fertilizer production. The process described uses solvent extraction for recovering uranium from phosphoric acid (sulfuric acid attack) and from phosphonitric acid (nitric acid attack). The extractant used is either a DEPA-TOPO mixture or a mixture of DEPA-TBP. The method selected for the industrial-scale units is a ''one-cycle, extraction-stripping process'' that differs from the ''two-cycle, extraction stripping process'' developed by the Oak Ridge National Laboratory (ORNL). In the ''one-cycle method'' both uranium and the rare earths are co-extracted and then selectively stripped by techniques that simultaneously produce precipitates. The first stripping operation selectively recovers a rare earth precipitate. Uranium is obtained from the second-stage stripping operation as ''green cake'' (a fluoride of U4+), which can be readily transformed to high purity UFO6. The treated phosphoric acid produces a triple superphosphate (TSP) of low radioactivity and diammonium phosphate (DAP) of no radioactivity. Three uranium recovery plants have been built adjacent to the existing phosphoric acid plants and are to be put into operation soon. Each plant can produce approximately 30 tonnes per year of uranium. The technology for conversion of the ''green cake'' to nuclear grade diuranate has also been finalized. Estimates indicate tha the ''one-cycle extraction-stripping process'' has a lower capital investment cost than the ''two-cycle extraction-stripping process'', and the projected operating costs are 25-30 US$/kg of U. (author). 8 refs, 2 figs

  9. 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.)

  10. Depleted uranium in Japan

    International Nuclear Information System (INIS)

    In Japan, depleted uranium ammunition is regarded as nuclear weapons and meets with fierce opposition. The fact that US Marines mistakenly fired bullets containing depleted uranium on an island off Okinawa during training exercises in December 1995 and January 1996, also contributes. The overall situation in this area in Japan is outlined. (P.A.)

  11. Uranium Measurements and Attributes

    International Nuclear Information System (INIS)

    It may be necessary to find the means to determine unclassified attributes of uranium in nuclear weapons or their components for future transparency initiatives. We briefly describe the desired characteristics of attribute measurement systems for transparency. The determination of uranium attributes; in particular, by passive gamma-ray detection is a formidable challenge

  12. Uranium: abundance or shortage?

    Energy Technology Data Exchange (ETDEWEB)

    Steyn, J. [Energy Resources International, Inc., Washington, DC (United States)

    1997-09-01

    With large uranium stockpiles, particularly in the form of HEU, continuing to be the dominant factor in the world uranium market, buyers should be able to enter into attractive long-term commitments for the future. Nevertheless, producers are now able to see forward with some degree of certainty and are expected to meet their planned levels of production and demand. (author).

  13. Developments in uranium resources, production, demand and the environment. Proceedings of a technical committee meeting

    International Nuclear Information System (INIS)

    activities as well as its participation in secondary supply sources such as commercialization of weapons grade uranium. Uranium supply from the developing countries could be increasingly important in satisfying worldwide reactor requirements over time. At the same time, it represents only one segment of total supply, which also includes production from developed countries plus secondary supply including inventory draw down, HEU, MOX, reprocessed uranium and re-enrichment of tails. A model developed by the IAEA is presented that provides for long term forecasting of uranium requirements for given sets of parameters including nuclear power projections and fuel cycle strategies. A companion presentation reviews the relationship between options at the backend of the nuclear fuel cycle and uranium market prices. These relationships impact the economics and therefore the availability of secondary supply

  14. Spectroscopic properties and laser performance of Tm:YAG ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Fei, B.J. [Key Lab of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Huang, J.Q.; Guo, W.; Huang, Q.F. [Key Lab of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Chen, J.; Tang, F. [Key Lab of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Wang, W.C. [Department of Physics, Renmin University of China, Beijing 100872 (China); Cao, Y.G., E-mail: caoyongge@fjirsm.ac.cn [Key Lab of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Department of Physics, Renmin University of China, Beijing 100872 (China)

    2013-10-15

    Tm:YAG laser ceramics were fabricated by solid-state reaction and simple vacuum sintering, and their spectroscopic characteristics were investigated in detail. High fluorescence quantum efficiency, long fluorescence lifetime and low up-conversion losses were demonstrated, which indicated that such ceramics could be used as laser gain media. Laser operation at 2 μm via {sup 3}F{sub 4}→{sup 3}H{sub 6} transition was realized. The maximum output power of 593 mW at 2007 nm was acquired with an optical conversion efficiency of 15.6%. -- Highlights: • Optical grade Tm:YAG laser ceramics were prepared. • Detail spectroscopic properties of Tm:YAG ceramic were investigated. • Cross-relaxation mechanisms of Tm{sup 3+} based on the emission spectra were elaborated. • Laser output of 593 mW was realized with an optical conversion efficiency of 15.6%.

  15. Verification of ceramic structures

    NARCIS (Netherlands)

    Behar-Lafenetre, S.; Cornillon, L.; Rancurel, M.; Graaf, D. de; Hartmann, P.; Coe, G.; Laine, B.

    2012-01-01

    In the framework of the "Mechanical Design and Verification Methodologies for Ceramic Structures" contract [1] awarded by ESA, Thales Alenia Space has investigated literature and practices in affiliated industries to propose a methodological guideline for verification of ceramic spacecraft and instr

  16. Modified anion-exchange method for determination of thorium in uranium based materials

    International Nuclear Information System (INIS)

    This paper details a modified anion-exchange method for estimation of thorium in uranium based samples like uranium dioxide powders, pellets and uranyl nitrate solutions. The method involves separation of thorium from uranium from 3M commercial grade HCl containing 15% NaCl through an anion-exchange resin. The uranium free effluent containing the analyte(thorium) is determined spectrophotometrically by exploiting absorption of the thorium-arsenazo III complex at 660 nm. The method has a precision of about ±2% at 50 ppm level. (author). 3 refs., 1 tab

  17. Reconnaissance for uranium in asphalt-bearing rocks in the western states

    Science.gov (United States)

    Hail, William James, Jr.

    1955-01-01

    An appraisal of asphalt-bearing rocks as potential sources of uranium was made during 1953 and 1954 by examining deposits in 45 areas in California, Utah, Wyoming, Montana, New Mexico, Texas, Oklahoma, and Missouri.  A total of 202 samples from these areas was analyzed for uranium. The oldest rocks sampled are Ordovician in age, and the youngest are Recent. Although none of the deposits are of value at this time as a source of uranium, some of the deposits may constitute a low grade uranium resource whose recovery will depend upon the primary use to which the asphalt is placed.

  18. Radiation protection as part of a uranium mine pre-feasibility study

    International Nuclear Information System (INIS)

    Golder Associates Ltd. (Golder) has conducted a number of pre-feasibility studies for prospective uranium mining projects. This work has ranged from a preliminary scoping analysis of the viability of a particular project to a formal pre-feasibility study. This paper will address the radiation protection requirements for uranium mining and the impact of these radiation protection requirements on the feasibility of a uranium production project. As is discussed, the ore grades of an ore body will strongly influence the choice of mining methods that are available for any specific project. This in turn will affect the projected capital and operating costs for a prospective uranium production facility. (author)

  19. EPR of uranium ions

    International Nuclear Information System (INIS)

    A review of the electron paramagnetic resonance data on the uranium ions is given. After a general account of the electronic structure of the uranium free atoms and ions, the influence of the external fields (magnetic field, crystal fields) is discussed. The main information obtained from EPR studies on the uranium ions in crystals are emphasized: identification of the valence and of the ground electronic state, determination of the structure of the centers, crystal field effects, role of the intermediate coupling and of the J-mixing, role of the covalency, determination of the nuclear spin, maqnetic dipole moment and electric quadrupole moment of the odd isotopes of uranium. These data emphasize the fact that the actinide group has its own identity and this is accutely manifested at the beginning of the 5fsup(n) series encompassed by the uranium ions. (authors)

  20. Management of depleted uranium

    International Nuclear Information System (INIS)

    Large stocks of depleted uranium have arisen as a result of enrichment operations, especially in the United States and the Russian Federation. Countries with depleted uranium stocks are interested in assessing strategies for the use and management of depleted uranium. The choice of strategy depends on several factors, including government and business policy, alternative uses available, the economic value of the material, regulatory aspects and disposal options, and international market developments in the nuclear fuel cycle. This report presents the results of a depleted uranium study conducted by an expert group organised jointly by the OECD Nuclear Energy Agency and the International Atomic Energy Agency. It contains information on current inventories of depleted uranium, potential future arisings, long term management alternatives, peaceful use options and country programmes. In addition, it explores ideas for international collaboration and identifies key issues for governments and policy makers to consider. (authors)

  1. Uranium dioxide electrolysis

    Science.gov (United States)

    Willit, James L.; Ackerman, John P.; Williamson, Mark A.

    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.

  2. Uranium triamidoamine chemistry.

    Science.gov (United States)

    Gardner, Benedict M; Liddle, Stephen T

    2015-07-01

    Triamidoamine (Tren) complexes of the p- and d-block elements have been well-studied, and they display a diverse array of chemistry of academic, industrial and biological significance. Such in-depth investigations are not as widespread for Tren complexes of uranium, despite the general drive to better understand the chemical behaviour of uranium by virtue of its fundamental position within the nuclear sector. However, the chemistry of Tren-uranium complexes is characterised by the ability to stabilise otherwise reactive, multiply bonded main group donor atom ligands, construct uranium-metal bonds, promote small molecule activation, and support single molecule magnetism, all of which exploit the steric, electronic, thermodynamic and kinetic features of the Tren ligand system. This Feature Article presents a current account of the chemistry of Tren-uranium complexes.

  3. Uranium deposit research, 1983

    International Nuclear Information System (INIS)

    Research on uranium deposits in Canada, conducted as a prerequisite for assessment of the Estimated Additional Resources of uranium, revealed that (a) the uranium-gold association in rudites of the Huronian Supergroup preferably occurs in the carbon layers; (b) chloritized ore at the Panel mine, Elliot Lake, Ontario, occurs locally in tectonically disturbed areas in the vicinity of diabase dykes; (c) mineralization in the Black Sturgeon Lake area, Ontario, formed from solutions in structural and lithological traps; (d) the Cigar Lake deposit, Saskatchewan, has two phases of mineralization: monomineralic and polymetallic; (e) mineralization of the JEB (Canoxy Ltd.) deposit is similar to that at McClean Lake; (f) the uranium-carbon assemblage was identified in the Claude deposit, Carswell Structure; and (g) the Otish Mountains area, Quebec, should be considered as a significant uranium-polymetallic metallogenic province

  4. Foreign uranium supply

    International Nuclear Information System (INIS)

    Known foreign uranium resources are concentrated in a few countries. The resources of many countries are largely unassessed, but the known uranium countries appear to have the best potential for future expansion. Availability of supply from known resources will depend on resolution of national policies regarding uranium production, ownership and export, and actions of the mining industry. Foreign uranium demand projections have decreased markedly in the last few years, and currently planned and attainable production should be adequate through the 1980's. Longer term resources and supply outlook are still a major concern to both those planning electric supply systems based on converter reactors and those considering reprocessing and recycle of uranium and plutonium and development of breeder reactors. Work continues to clarify long-term supply in several countries and internationally, but more effort, and time, will be needed to clarify these issues

  5. Underground bioleaching: extracting from low-grade ore

    International Nuclear Information System (INIS)

    In 1984, Denison Mines began a research and demonstration project on the engineering aspects of bacterial leaching of low-grade uranium ore at Elliot Lake. The leaching solution was acidic mine water enriched in bacterial nutrients and innoculated with Thiobacillus ferrooxidans. Leaching of one stope was found to be impeded by fungi of the genus penicillium. Although fungal growth on leaching stopes must be prevented, research is proceeding on the potential use of the fungi to concentrate uranium from bioleaching solutions

  6. Cuddapah uranium province, Andhra Pradesh role of basement granites, tectonism and geochemistry

    International Nuclear Information System (INIS)

    The Cuddapah Uranium Province encompasses two economically viable genetic types of uranium deposits as the carbonate-hosted stratabound uranium deposits around Tummalapalle-Rachakuntapalle area, and the unconformity-proximal type in basement granitoids and overlying Srisailam/Banganapalle quartzite in the Lambapur-Peddagattu-Chitrial-Koppunuru area . Besides, the basin characteristically hosts important occurrences, of fracture controlled uranium mineralisation in Gulcheru quartzite near Gandi and in basement granitoid around Lakkireddipalle-Rayachoti; shear-controlled along the thrusted eastern margin of Cuddapah basin in basic metavolcanics and schists at Gudarukoppu and Kasturigattu. In the northern part of the basin, uranium deposits of Lambapur, Peddagattu, Chitrial, and Koppunuru area characteristically show association of ore bodies along structures formed by intersection of prominent basement fractures with the unconformity separating Srisailam and Palnad sediments from the basement. In the southwestern part of the basin, potential carbonate-hosted, stratabound uranium mineralisation extends over a 160 km long belt from Chelumpalli to Maddimadugu with large-tonnage, low-grade, uranium deposits in Tummallapalle-Rachakuntapalle area. The unconformity-proximal and fracture controlled deposits/prospects characteristically share a common source for uranium, repeated tectonism, weathering of the basement granitoids and episodic, epigenetic hydrothermal processes of uranium mineralisation. This paper evaluates the role of granitoids spatially and temporally associated with uranium mineralisation in making the Cuddapah Basin a unique uranium province. (author)

  7. Sweetwater Uranium Project. Draft environmental statement

    International Nuclear Information System (INIS)

    The proposed action is the issuance of a Source Material License to Minerals Exploration Company for the construction and operation of the proposed Sweetwater Uranium Mill with a nominal capacity of 3000 tons (2.7 x 106 kg) per day of uranium ore in Wyoming. The applicant proposes also to construct a heap-leaching and resin ion-exchange facility to extract uranium from low-grade ores and mine water. Impacts to the area due to the operation of the Sweetwater Uranium Mine/Mill Project will result in: Alternations of up to 2200 acres by the mill, mine pit area, and roads, and about 3450 acres of Battle Spring Flat to be inundated by mine dewatering operations; increase in the existing background radiation levels; socioeconomic effects on Rawlins and other nearby areas; and tailings from the mill will be produced at a rate of about 3000 tons (2.7 x 106 kg) per day and will be stored onsite in a lined impoundment. Conditions for the issuance of the license are given

  8. Mining and milling of uranium ore: Indian scenario

    International Nuclear Information System (INIS)

    The occurrence of uranium minerals in Singhbhum Thrust belt of Eastern India has been known since 1937. In 1950, a team of geologists of the Atomic Minerals Division was assigned to closely examine this 160 km long belt. Since then, several occurrences of uranium have been found and a few of them have sufficient grade and tonnage for commercial exploitation. In 1967, the Government of India formed Uranium Corporation of India Ltd., under the administrative control of the Department of Atomic Energy, with the specific objective of mining and processing of uranium ore and produce uranium concentrates. At present the Corporation operates three underground uranium mines, one ore processing plant with expanded capacity, and two uranium recovery plants. Continuing investigations by the Atomic Mineral Division has discovered several new deposits and favourable areas. The most notable is the large Domiasiat deposit of the sandstone type found in the State of Meghalaya. This deposit is now being considered for commercial exploitation using the in-situ leaching technology. (author)

  9. Radiation protection in uranium mining and milling industry

    International Nuclear Information System (INIS)

    The first phase of the Nuclear Fuel Cycle is exploration for uranium and the next is mining and milling of uranium ore. This phase is mostly characterised by low levels of radioactivity and radiation exposure of the workers involved. Yet it is a paradoxical truth that incidence of cancer among the work force, especially miners, due to occupational radiation exposure (from radon and decay products) has been proved only in uranium mines in the entire Nuclear Fuel Cycle. Of course such incidence occurred before the detrimental effect of radiation exposure was realised and understood. Therefore it is important to familiarise oneself with the radiation hazards prevalent in the uranium mining and milling facilities so as to take appropriate remedial measures for the protection of not only the workers but also the public at large. There are both open cast and underground uranium mines around the world. Radiation hazards are considerably less significant in open cast mines than in underground mines unless the ore grade is very high. By default therefore the discussion which ensues relates mainly to radiation hazards in underground uranium mines and associated milling operations. The discussion gives a brief outline of typical uranium mine and mining and milling operations. This is followed by a description of the radiation hazards therein and protection measures that are to be taken to minimise radiation exposure. (author)

  10. Ceramics As Materials Of Construction

    OpenAIRE

    Zaki, A.; Eteiba, M. B.; Abdelmonem, N.M.

    1988-01-01

    This paper attempts to review the limitations for using the important ceramics in contact with corrosive media. Different types of ceramics are included. Corrosion properties of ceramics and their electrical properties are mentioned. Recommendations are suggested for using ceramics in different media.

  11. Unconformity-related uranium deposits, Athabasca area, Saskatchewan, and East Alligator Rivers area, Northern Territory, Australia

    International Nuclear Information System (INIS)

    Most unconformity-type uranium deposits in Saskatchewan occur within a few tens of metres above and/or below the basal unconformity of the 1.45 b.y. Athabasca Sandstone. Graphitic basement rocks coincident with post-Athabasca faulting or brecciation at or near the unconformity are important in localizing uranium deposits which form as tabular, ribbon-like bodies with grades averaging over 2 percent uranium and containing up to 50,000 tonnes U3O8. Some of these deposits have similar contents of nickel and arsenic. In the genetic model used to explain these deposits, traces of uranium were leached from the sandstone and basement rocks by oxidized formation waters. A thick clay regolith absorbed uranium from the solution, and the fixed uranium was reduced through an indirect reaction with graphite. The clay mineral surfaces were thus continuously cleared to allow further adsorption. Fluid convection was induced by topographic relief and/or crustal heating from radioactive decay, and would continue uranium deposition until all permeability was plugged by minerals. The East Alligator Rivers uranium deposits in Northern Territory, Australia occur within Middle Proterozoic quartz-chlorite and quartz-muscovite schists overlain by sandstone. Highest grades occur in silicified breccias where carbonate beds were leached out. Mineralization ages are both pre- and post-Kombolgie Sandstone, but, to date, no significant uranium mineralization has been found in the sandstone. There are many similarities with Saskatchewan deposits, but also important differences. (auth)

  12. Uranium deposits in Africa

    International Nuclear Information System (INIS)

    Africa is not only known for its spectacular diamond, gold, copper, chromium, platinum and phosphorus deposits but also for its uranium deposits. At least two uranium provinces can be distinguished - the southern, with the equatorial sub-province; and the south Saharan province. Uranium deposits are distributed either in cratons or in mobile belts, the first of sandstone and quartz-pebble conglomerate type, while those located in mobile belts are predominantly of vein and similar (disseminated) type. Uranium deposits occur within Precambrian rocks or in younger platform sediments, but close to the exposed Precambrian basement. The Proterozoic host rocks consist of sediments, metamorphics or granitoids. In contrast to Phanerozoic continental uranium-bearing sediments, those in the Precambrian are in marginal marine facies but they do contain organic material. The geology of Africa is briefly reviewed with the emphasis on those features which might control the distribution of uranium. The evolution of the African Platform is considered as a progressive reduction of its craton area which has been affected by three major Precambrian tectonic events. A short survey on the geology of known uranium deposits is made. However, some deposits and occurrences for which little published material is available are treated in more detail. (author)

  13. Liquid phase sintered SiC ceramics from starting materials of different grade Cerâmicas à base de SiC sinterizadas via fase líquida a partir de matérias-primas de diferentes purezas

    Directory of Open Access Journals (Sweden)

    V. A. Izhevskyi

    2004-09-01

    Full Text Available Possibility of high performance ceramics manufactured from commercial SiC powder of technical grade has been shown. Sintering behavior and microstructure formation under conditions of liquid phase sintering (LPS with oxynitride sintering aids (AlN-Y2O3 of three SiC-based compositions have been investigated. Two of the compositions were based on Alcoa 1000 SiC powder of technical grade, and the third one, which was used as a reference, was based on H.C. Starck UF-15 fine grade commercial powder. Milling process used for Alcoa 1000 SiC powder granulometry improvement has been investigated in detail, while chemical treatment of milled SiC powders has been used for pick-up impurities removal. Dilatometric experiments showed that SiC powder of technical grade after appropriate treatment exhibits sinterability comparable with the fine grade SiC. Microstructural investigations performed on sintered samples showed that the final microstructure of the Alcoa 1000 SiC based materials was practically identical with the H.C. Starck SiC based reference ones. Preliminary investigations of hardness and fracture toughness were carried out revealing excellent results for the materials produced from cheaper, nationally produced starting powder.Neste trabalho é apresentada a possibilidade de obtenção de cerâmicas de SiC de alto desempenho a partir de matéria-prima comercial de grau técnico. Foi realizado o estudo de sinterização via fase líquida e desenvolvimento microestrutural de três composições à base de SiC tendo como aditivos de sinterização AlN e Y2O3 . Duas destas composições são à base de SiC-1000 da Alcoa, grau técnico, e a terceira, utilizada como referência, à base do UF-15 da H.C. Starck - Alemanha, pó comercial de granulometria fina. O processo de moagem do pó SiC-1000 da Alcoa foi acompanhado por medidas de distribuição granulométrica e posterior ataque químico, para remoção de impurezas. Os pós de grau técnico, ap

  14. Uranium resource assessments

    International Nuclear Information System (INIS)

    The objective of this investigation is to examine what is generally known about uranium resources, what is subject to conjecture, how well do the explorers themselves understand the occurrence of uranium, and who are the various participants in the exploration process. From this we hope to reach a better understanding of the quality of uranium resource estimates as well as the nature of the exploration process. The underlying questions will remain unanswered. But given an inability to estimate precisely our uranium resources, how much do we really need to know. To answer this latter question, the various Department of Energy needs for uranium resource estimates are examined. This allows consideration of whether or not given the absence of more complete long-term supply data and the associated problems of uranium deliverability for the electric utility industry, we are now threatened with nuclear power plants eventually standing idle due to an unanticipated lack of fuel for their reactors. Obviously this is of some consequence to the government and energy consuming public. The report is organized into four parts. Section I evaluates the uranium resource data base and the various methodologies of resource assessment. Part II describes the manner in which a private company goes about exploring for uranium and the nature of its internal need for resource information. Part III examines the structure of the industry for the purpose of determining the character of the industry with respect to resource development. Part IV arrives at conclusions about the emerging pattern of industrial behavior with respect to uranium supply and the implications this has for coping with national energy issues

  15. High pressure ceramic joint

    Science.gov (United States)

    Ward, Michael E.; Harkins, Bruce D.

    1993-01-01

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present joint when used with recuperators increases the use of ceramic components which do not react to highly corrosive gases. Thus, the present joint used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present joint is comprised of a first ceramic member, a second ceramic member, a mechanical locking device having a groove defined in one of the first ceramic member and the second ceramic member. The joint and the mechanical locking device is further comprised of a refractory material disposed in the groove and contacting the first ceramic member and the second ceramic member. The present joint mechanically provides a high strength load bearing joint having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

  16. Economic evaluation of preconcentration of uranium ores

    International Nuclear Information System (INIS)

    The economics of two options for the preconcentration of low-grade uranium ores prior to hydrochloric acid leaching were studied. The first option uses flotation followed by wet high-intensity magnetic separation. The second option omits the flotation step. In each case it was assumed that most of the pyrite in the ore would be recovered by froth flotation, dewatered, and roasted to produce sulphuric acid and a calcine suitable for acid leaching. Savings in operating costs from preconcentration are offset by the value of uranium losses. However, a capital saving of approximately 6 million dollars is indicated for each preconcentration option. As a result of the capital saving, preconcentration appears to be economically attractive when combined with hydrochloric acid leaching. There appears to be no economic advantage to preconcentration in combination with sulphuric acid leaching of the ore

  17. Ceramic Hosts for Fission Products Immobilization

    International Nuclear Information System (INIS)

    Natural spinel, perovskite and zirconolite rank among the most leach resistant of mineral forms. They also have a strong affinity for a large number of other elements and including actinides. Specimens of natural perovskite and zirconolite were radioisotope dated and found to have survived at least 2 billion years of natural process while still remain their loading of uranium and thorium . Developers of the Synroc waste form recognized and exploited the capability of these minerals to securely immobilize TRU elements in high-level waste . However, the Synroc process requires a relatively uniform input and hot pressing equipment to produce the waste form. It is desirable to develop alternative approaches to fabricate these durable waste forms to immobilize the radioactive elements. One approach is using a high temperature process to synthesize these mineral host phases to incorporate the fission products in their crystalline structures. These mineral assemblages with immobilized fission products are then isolated in a durable high temperature glass for periods measured on a geologic time scale. This is a long term research concept and will begin with the laboratory synthesis of the pure spinel (MgAl2O4), perovskite (CaTiO3) and zirconolite (CaZrTi2O7) from their constituent oxides. High temperature furnace and/or thermal plasma will be used for the synthesis of these ceramic host phases. Nonradioactive strontium oxide will be doped into these ceramic phases to investigate the development of substitutional phases such as Mg1-xSrxAl2O4, Ca1-xSrxTiO3 and Ca1-xSrxZrTi2O7. X-ray diffraction will be used to establish the crystalline structures of the pure ceramic hosts and the substitution phases. Scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) will be performed for product morphology and fission product surrogates distribution in the crystalline hosts. The range of strontium doping is planned to reach the full substitution of the divalent

  18. Ceramic Hosts for Fission Products Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Peter C Kong

    2010-07-01

    Natural spinel, perovskite and zirconolite rank among the most leach resistant of mineral forms. They also have a strong affinity for a large number of other elements and including actinides. Specimens of natural perovskite and zirconolite were radioisotope dated and found to have survived at least 2 billion years of natural process while still remain their loading of uranium and thorium . Developers of the Synroc waste form recognized and exploited the capability of these minerals to securely immobilize TRU elements in high-level waste . However, the Synroc process requires a relatively uniform input and hot pressing equipment to produce the waste form. It is desirable to develop alternative approaches to fabricate these durable waste forms to immobilize the radioactive elements. One approach is using a high temperature process to synthesize these mineral host phases to incorporate the fission products in their crystalline structures. These mineral assemblages with immobilized fission products are then isolated in a durable high temperature glass for periods measured on a geologic time scale. This is a long term research concept and will begin with the laboratory synthesis of the pure spinel (MgAl2O4), perovskite (CaTiO3) and zirconolite (CaZrTi2O7) from their constituent oxides. High temperature furnace and/or thermal plasma will be used for the synthesis of these ceramic host phases. Nonradioactive strontium oxide will be doped into these ceramic phases to investigate the development of substitutional phases such as Mg1-xSrxAl2O4, Ca1-xSrxTiO3 and Ca1-xSrxZrTi2O7. X-ray diffraction will be used to establish the crystalline structures of the pure ceramic hosts and the substitution phases. Scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) will be performed for product morphology and fission product surrogates distribution in the crystalline hosts. The range of strontium doping is planned to reach the full substitution of the divalent

  19. Uranium mining and milling

    International Nuclear Information System (INIS)

    In this report uranium mining and milling are reviewed. The fuel cycle, different types of uranium geological deposits, blending of ores, open cast and underground mining, the mining cost and radiation protection in mines are treated in the first part of this report. In the second part, the milling of uranium ores is treated, including process technology, acid and alkaline leaching, process design for physical and chemical treatment of the ores, and the cost. Each chapter is clarified by added figures, diagrams, tables, and flowsheets. (HK)

  20. Production of uranium peroxide

    International Nuclear Information System (INIS)

    The invention provides a process for recovering uranium values as uranium peroxide from an aqueous uranyl solution containing dissolved vanadium and sodium impurities. It consists of treating the uranyl solution with hydrogen peroxide in an amount equal to at least 0.5 part H2O2 per part of vanadium (V2O5) in solution in excess of the stoichiometric (1.26 parts/part U3O8) amount required to form the uranium peroxide. The hydrogen peroxide treatment is carried out in three phases. (auth)

  1. Uranium recovery from waste of the nuclear fuel cycle plants at IPEN-CNEN/SP, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Antonio A.; Ferreira, Joao C.; Zini, Josiane; Scapin, Marcos A.; Carvalho, Fatima Maria Sequeira de, E-mail: afreitas@ipen.b, E-mail: jcferrei@ipen.b, E-mail: jzini@ipen.b, E-mail: mascapin@ipen.b, E-mail: fatimamc@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Sodium diuranate (DUS) is a uranium concentrate produced in monazite industry with 80% typical average grade of U{sup 3}O{sup 8}, containing sodium, silicon, phosphorus, thorium and rare earths as main impurities. Purification of such concentrate was achieved at the nuclear fuel cycle pilot plants of uranium at IPEN by nitric dissolution and uranium extraction into an organic phase using TBP/Varsol, while the aqueous phase retains impurities and a small quantity of non extracted uranium; both can be recovered later by precipitation with sodium hydroxide. Then the residual sodium diuranate goes to a long term storage at a safeguards deposit currently reaching 20 tonnes. This work shows how uranium separation and purification from such bulk waste can be achieved by ion exchange chromatography, aiming at decreased volume and cost of storage, minimization of environmental impacts and reduction of occupational doses. Additionally, the resulting purified uranium can be reused in nuclear fuel cycle.(author)

  2. Uranium recovery from waste of the nuclear fuel cycle plants at IPEN-CNEN/SP, Brazil

    International Nuclear Information System (INIS)

    Sodium diuranate (DUS) is a uranium concentrate produced in monazite industry with 80% typical average grade of U3O8, containing sodium, silicon, phosphorus, thorium and rare earths as main impurities. Purification of such concentrate was achieved at the nuclear fuel cycle pilot plants of uranium at IPEN by nitric dissolution and uranium extraction into an organic phase using TBP/Varsol, while the aqueous phase retains impurities and a small quantity of non extracted uranium; both can be recovered later by precipitation with sodium hydroxide. Then the residual sodium diuranate goes to a long term storage at a safeguards deposit currently reaching 20 tonnes. This work shows how uranium separation and purification from such bulk waste can be achieved by ion exchange chromatography, aiming at decreased volume and cost of storage, minimization of environmental impacts and reduction of occupational doses. Additionally, the resulting purified uranium can be reused in nuclear fuel cycle.(author)

  3. Eldorado Port Hope refinery - uranium production (1933-1951)

    International Nuclear Information System (INIS)

    Since the discovery of pitchblende in 1930 by Gilbert LaBine at Great Bear Lake (GBL), North West Territories, uranium has played a central role in the growth of the Canadian mining sector and it in turn has propelled the country into it's present position as the world's top uranium producer. The rich ore mined there was used originally by Eldorado Gold Mines Limited to build a business based on the extraction of radium, which was selling at $70,000 a gram at the time, and silver which was present in the ore in commercial amounts. The mine site on GBL became known as Port Radium. In 1933 Eldorado brought a refinery on-line at Port Hope, Ontario nearly 4,000 miles away from the mine, and began to produce radium, silver and uranium products. Initially uranium played a minor role in the business and the products were sold into the ceramics industry to manufacture a variety of crockery with long-lasting colours. In addition, there were sales and loans of uranium products to research laboratories that were exploring nuclear energy for possible use in weapons and power generation, as the potential for this was clearly understood from 1939 onwards. These laboratories included the National Research Council (George Laurence), Columbia University (Enrico Fermi) and International Chemical Industries (J.P. Baxter). With the beginning of World War II the radium business suffered from poor sales and by 1940 the mine was closed but the refinery continued operation, using accumulated stockpiles. By 1942 uranium had become a strategic material, the mine was reopened, and the refinery began to produce large quantities of uranium oxide destined for The Manhattan Project. As events unfolded Eldorado was unable to produce sufficient ore from GBL so that a large quantity of ore from the Belgian Congo was also processed at Port Hope. Ultimately, as a result of the efforts of this enterprise, World War II was finally ended by use of atomic weapons. After World War II the refinery

  4. Strategies for denaturing the weapons-grade plutonium stockpile

    Energy Technology Data Exchange (ETDEWEB)

    Buckner, M.R.; Parks, P.B.

    1992-10-01

    In the next few years, approximately 50 metric tons of weapons-grade plutonium and 150 metric tons of highly-enriched uranium (HEU) may be removed from nuclear weapons in the US and declared excess. These materials represent a significant energy resource that could substantially contribute to our national energy requirements. HEU can be used as fuel in naval reactors, or diluted with depleted uranium for use as fuel in commercial reactors. This paper proposes to use the weapons-grade plutonium as fuel in light water reactors. The first such reactor would demonstrate the dual objectives of producing electrical power and denaturing the plutonium to prevent use in nuclear weapons.

  5. The APS ceramic chambers

    Energy Technology Data Exchange (ETDEWEB)

    Milton, S.; Warner, D.

    1994-07-01

    Ceramics chambers are used in the Advanced Photon Source (APS) machines at the locations of the pulsed kicker and bumper magnets. The ceramic will be coated internally with a resistive paste. The resistance is chosen to allow the low frequency pulsed magnet field to penetrate but not the high frequency components of the circulating beam. Another design goal was to keep the power density experienced by the resistive coating to a minimum. These ceramics, their associated hardware, the coating process, and our recent experiences with them are described.

  6. Uraniferous opal, Virgin Valley, Nevada: conditions of formation and implications for uranium exploration

    Science.gov (United States)

    Zielinski, R.A.

    1982-01-01

    Uraniferous, fluorescent opal, which occurs in tuffaceous sedimentary rocks at Virgin Valley, Nevada, records the temperature and composition of uranium-rich solutions as well as the time of uranium-silica coprecipitation. Results are integrated with previous geologic and geochronologic data for the area to produce a model for uranium mobility that may be used to explore for uranium deposits in similar geologic settings. Uraniferous opal occurs as replacements of diatomite, or silicic air-fall ash layers in tuffaceous lakebeds of the Virgin Valley Formation (Miocene) of Merriam (1907). Fission-track radiography shows uranium to be homogeneously dispersed throughout the opal structure, suggesting coprecipitation of dissolved uranium and silica gel. Fluid inclusions preserved within opal replacements of diatomite have homogenization temperatures in the epithermal range and are of low salinity. Four samples of opal from one locality all have U-Pb apparent ages which suggest uraniferous opal precipitation in late Pliocene time. These ages correspond to a period of local, normal faulting, and highangle faults may have served as vertical conduits for transport of deep, thermalized ground water to shallower levels. Lateral migration of rising solutions occurred at intersections of faults with permeable strata. Silica and some uranium were dissolved from silica-rich host strata of 5-20 ppm original uranium content and reprecipitated as the solutions cooled. The model predicts that in similar geologic settings, ore-grade concentrations of uranium will occur in permeable strata that intersect high-angle faults and that contain uranium source rocks as well as efficient reductant traps for uranium. In the absence of sufficient quantities of reductant materials, uranium will be flushed from the system or will accumulate in low-grade disseminated hosts such as uraniferous opal. ?? 1982.

  7. Uranium in granites

    International Nuclear Information System (INIS)

    Recent research activities of the Canadian Uranium in Granites Study are presented in 18 papers and 3 abstracts. 'Granites' is used as a generic term for granitoids, granitic rocks, and plutonic rocks

  8. Ontario's uranium mining industry

    International Nuclear Information System (INIS)

    This report traces the Ontario uranium mining industry from the first discovery of uranium north of Sault Ste. Marie through the uranium boom of the 1950's when Elliot Lake and Bancroft were developed, the cutbacks of the 1960s, the renewed enthusiasm in exploration and development of the 1970s to the current position when continued production for the domestic market is assured. Ontario, with developed mines and operational expertise, will be in a position to compete for export markets as they reopen. The low level of expenditures for uranium exploration and the lack of new discoveries are noted. The report also reviews and places in perspective the development of policies and regulations governing the industry and the jurisdictional relationships of the Federal and Provincial governments

  9. 300 AREA URANIUM CONTAMINATION

    International Nuclear Information System (INIS)

    (smbullet) Uranium fuel production (smbullet) Test reactor and separations experiments (smbullet) Animal and radiobiology experiments conducted at the. 331 Laboratory Complex (smbullet) .Deactivation, decontamination, decommissioning,. and demolition of 300 Area facilities

  10. Uranium Location Database

    Data.gov (United States)

    U.S. Environmental Protection Agency — A GIS compiled locational database in Microsoft Access of ~15,000 mines with uranium occurrence or production, primarily in the western United States. The metadata...

  11. Selective separation of uranium

    International Nuclear Information System (INIS)

    A process for the selective separation of uranium from elements accompanying it in a uranium-containing ore is claimed. It comprises preparing a uranium-containing solution; adding hydrochloric acid in an amount sufficient to form complex anions of the type (UO2Clsub(n))sup(2-n) where n is 3 or 4, or sulfuric acid in an amount sufficient to form complex anions of the type UO2(SO4)sub(m)sup(2-2m) where m is 2 or 3; adding a cationic surface active agent which forms a difficultly soluble precipitate with the complex anion; subjecting the solution to a gas flotation step to produce a foam fraction containing the pecipitate and a liquid fraction; separating the two fractions; and recovering uranium from the foam fraction

  12. Uranium determination in zirconium

    International Nuclear Information System (INIS)

    The method used for the spectrometric uranium determination with 2-(2-thiolase)-5-diethylaminophenol was modified for its application in the zirconium samples analysis with an uranium content of the 0.1% order. The samples, previously dissolved in nitric acid, were submitted to a separative stage of liquid-liquid extraction, with a trioctylphosphine (TOPO) oxide diluted in cyclohexane. A sodium fluoride aqueous solution was necessary to be aggregated in the spectrometric determination so as to complex the zirconium vestiges, which could be present, originated by the Zr/U high relation of the initial sample. Under the established working conditions, different spectrometric assays, dyes absorption spectra and its uranium complex, complex stability, PH influence determination of the dyes-uranium relation, calculation of the complex's apparent formation constant and its molar absorption, were performed. (Author)

  13. Uranium in alkaline rocks

    International Nuclear Information System (INIS)

    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential

  14. Uranium in alkaline rocks

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

    1978-04-01

    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential.

  15. Honest Grading, Grade Inflation and Reputation

    OpenAIRE

    Ehlers, Tim; Schwager, Robert

    2012-01-01

    When grades lose their informative value because the percentage of students receiving the best grade rises without any corresponding increase in ability, this is called grade inflation. Conventional wisdom says that such grade inflation is unavoidable since it is essentially costless to award good grades. In this paper, we point out an effect driving into the opposite direction: Grade inflation is not actually costless, since it has an impact on future cohorts of graduates, or, put differentl...

  16. Ceramic Solar Receiver

    Science.gov (United States)

    Robertson, C., Jr.

    1984-01-01

    Solar receiver uses ceramic honeycomb matrix to absorb heat from Sun and transfer it to working fluid at temperatures of 1,095 degrees and 1,650 degrees C. Drives gas turbine engine or provides heat for industrial processes.

  17. Ceramic fiber filter technology

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, B.L.; Janney, M.A.

    1996-06-01

    Fibrous filters have been used for centuries to protect individuals from dust, disease, smoke, and other gases or particulates. In the 1970s and 1980s ceramic filters were developed for filtration of hot exhaust gases from diesel engines. Tubular, or candle, filters have been made to remove particles from gases in pressurized fluidized-bed combustion and gasification-combined-cycle power plants. Very efficient filtration is necessary in power plants to protect the turbine blades. The limited lifespan of ceramic candle filters has been a major obstacle in their development. The present work is focused on forming fibrous ceramic filters using a papermaking technique. These filters are highly porous and therefore very lightweight. The papermaking process consists of filtering a slurry of ceramic fibers through a steel screen to form paper. Papermaking and the selection of materials will be discussed, as well as preliminary results describing the geometry of papers and relative strengths.

  18. Advanced Ceramics Property Measurements

    Science.gov (United States)

    Salem, Jonathan; Helfinstine, John; Quinn, George; Gonczy, Stephen

    2013-01-01

    Mechanical and physical properties of ceramic bodies can be difficult to measure correctly unless the proper techniques are used. The Advanced Ceramics Committee of ASTM, C-28, has developed dozens of consensus test standards and practices to measure various properties of a ceramic monolith, composite, or coating. The standards give the "what, how, how not, and why" for measurement of many mechanical, physical, thermal, and performance properties. Using these standards will provide accurate, reliable, and complete data for rigorous comparisons with other test results from your test lab, or another. The C-28 Committee has involved academics, producers, and users of ceramics to write and continually update more than 45 standards since the committee's inception in 1986. Included in this poster is a pictogram of the C-28 standards and information on how to obtain individual copies with full details or the complete collection of standards in one volume.

  19. Making Ceramic Cameras

    Science.gov (United States)

    Squibb, Matt

    2009-01-01

    This article describes how to make a clay camera. This idea of creating functional cameras from clay allows students to experience ceramics, photography, and painting all in one unit. (Contains 1 resource and 3 online resources.)

  20. Ranger uranium environmental enquiry

    International Nuclear Information System (INIS)

    The submission is divided into three sections. Section A considers the international implications of the development of uranium resources including economic and resource aspects and environmental and social aspects. Section B outlines the government's position on export controls over uranium and its effect on the introduction of nuclear power in Australia. Section C describes the licensing and regulatory functions that would be needed to monitor the environmental and health aspects of the Ranger project. (R.L.)

  1. Uranium leads political stakes

    International Nuclear Information System (INIS)

    Until the announcement by the federal Environment Minister Peter Garrett that the government would permit uranium mining at Beverly Four Mile, South Australia, there had been little news flow from the sector over the past year. Uranium was the first to turn down, even before the United States sub-prime mortgage crisis began to cause shock waves through the global economy, a report by BGF Equities analyst Warwick Grigor shows.

  2. Uranium determination in water

    International Nuclear Information System (INIS)

    In our laboratory, a procedure has been assessed to determine uranium content of water in normal situations. The method proposed without sample pre-treatment, is simple and rapid. Uranium mass is measured by fluorimetry. For calculation of detection limit (Ld) and quantification level (Lq) we used blank samples and the results were analyzed for different statistical test. The calculation of total propagated uncertainty and sources contribution on real samples are presented. (author)

  3. Uranium project. Geochemistry prospection

    International Nuclear Information System (INIS)

    Geochemistry studies the distribution of the chemicals elements in the terrestrial crust and its ways to migrate. The terminology used in this report is the following one: 1) Principles of the prospection geochemistry 2) Stages of the prospection geochemistry 3)utility of the prospection geochemistry 4) geochemistry of uranium 5) procedures used within the framework of uranium project 6) Average available 7) Selection of the zones of prospection geochemistry 8) Stages of the prospection, Sample preparation and analisis 9) Presentation of the results

  4. Uranium tailings bibliography

    International Nuclear Information System (INIS)

    A bibliography containing 1,212 references is presented with its focus on the general problem of reducing human exposure to the radionuclides contained in the tailings from the milling of uranium ore. The references are divided into seven broad categories: uranium tailings pile (problems and perspectives), standards and philosophy, etiology of radiation effects, internal dosimetry and metabolism, environmental transport, background sources of tailings radionuclides, and large-area decontamination

  5. Production of sized particles of uranium oxides and uranium oxyfluorides

    International Nuclear Information System (INIS)

    A process for converting uranium hexafluoride to uranium dioxide of a relatively large particle size in a fluidized bed reactor by mixing uranium hexafluoride with a mixture of steam and hydrogen to form a mixture of uranium oxide and uranium oxyfluoride seed particles of varying sizes, separating the larger particles from the smaller particles in a cyclone separator, recycling the smaller seed particles through the ejector to increase their size, and introducing the larger seed particles from the cyclone separator into a fluidized bed reactor where the seed particles serve as nuclei on which coarser particles of uranium dioxide are formed. (Patent Office Record)

  6. National Uranium Resource Evaluation. Volume 1. Summary of the geology and uranium potential of Precambrian conglomerates in southeastern Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Karlstrom, K.E.; Houston, R.S.; Flurkey, A.J.; Coolidge, C.M.; Kratochvil, A.L.; Sever, C.K.

    1981-02-01

    A series of uranium-, thorium-, and gold-bearing conglomerates in Late Archean and Early Proterozoic metasedimentary rocks have been discovered in southern Wyoming. The mineral deposits were found by applying the time and strata bound model for the origin of uranium-bearing quartz-pebble conglomerates to favorable rock types within a geologic terrane known from prior regional mapping. No mineral deposits have been discovered that are of current (1981) economic interest, but preliminary resource estimates indicate that over 3418 tons of uranium and over 1996 tons of thorium are present in the Medicine Bow Mountains and that over 440 tons of uranium and 6350 tons of thorium are present in Sierra Madre. Sampling has been inadequate to determine gold resources. High grade uranium deposits have not been detected by work to date but local beds of uranium-bearing conglomerate contain as much as 1380 ppM uranium over a thickness of 0.65 meters. This project has involved geologic mapping at scales from 1/6000 to 1/50,000 detailed sampling, and the evaluation of 48 diamond drill holes, but the area is too large to fully establish the economic potential with the present information. This first volume summarizes the geologic setting and geologic and geochemical characteristics of the uranium-bearing conglomerates. Volume 2 contains supporting geochemical data, lithologic logs from 48 drill holes in Precambrian rocks, and drill site geologic maps and cross-sections from most of the holes. Volume 3 is a geostatistical resource estimate of uranium and thorium in quartz-pebble conglomerates.

  7. National Uranium Resource Evaluation. Volume 1. Summary of the geology and uranium potential of Precambrian conglomerates in southeastern Wyoming

    International Nuclear Information System (INIS)

    A series of uranium-, thorium-, and gold-bearing conglomerates in Late Archean and Early Proterozoic metasedimentary rocks have been discovered in southern Wyoming. The mineral deposits were found by applying the time and strata bound model for the origin of uranium-bearing quartz-pebble conglomerates to favorable rock types within a geologic terrane known from prior regional mapping. No mineral deposits have been discovered that are of current (1981) economic interest, but preliminary resource estimates indicate that over 3418 tons of uranium and over 1996 tons of thorium are present in the Medicine Bow Mountains and that over 440 tons of uranium and 6350 tons of thorium are present in Sierra Madre. Sampling has been inadequate to determine gold resources. High grade uranium deposits have not been detected by work to date but local beds of uranium-bearing conglomerate contain as much as 1380 ppM uranium over a thickness of 0.65 meters. This project has involved geologic mapping at scales from 1/6000 to 1/50,000 detailed sampling, and the evaluation of 48 diamond drill holes, but the area is too large to fully establish the economic potential with the present information. This first volume summarizes the geologic setting and geologic and geochemical characteristics of the uranium-bearing conglomerates. Volume 2 contains supporting geochemical data, lithologic logs from 48 drill holes in Precambrian rocks, and drill site geologic maps and cross-sections from most of the holes. Volume 3 is a geostatistical resource estimate of uranium and thorium in quartz-pebble conglomerates

  8. Production of uranium peroxide

    International Nuclear Information System (INIS)

    The process of recovering uranium values as uranium peroxide from an aqueous uranyl solution containing dissolved vanadium and sodium impurities, characterized by treating the uranyl solution with hydrogen peroxide in an amount sufficient to have an excess of at least 0.5 parts H2O2 per part vanadium (V2O5) above the stoichio-metric amount required to form the uranium peroxide, the hydrogen peroxide treatment being carried out in three sequential phases consisting of: 1) a precipitation phase in which the hydrogen peroxide is added to the uranyl solution to precipitate the uranium peroxide and the pH of the reaction media maintained in the range of 3.0 to 7.0 for a period of 5 to 180 60 minutes after the hydrogen peroxide addition; 2) a digestion phase in which the pH of the reaction medium is maintained in the range of 3.0 to 7.0 for a period of 5 to 180 minutes and 3) a final phase in which the pH of the reaction media is maintained in the range of 4.0 to 7.0 for a period of 1 to 60 minutes during which time the uranium peroxide is separated from the reaction solution containing the dissolved vanadium and sodium impurities, the excess hydrogen peroxide aforesaid being maintained until the uranium peroxide is separated from the reaction mixture

  9. Selecting Ceramics - Introduction

    OpenAIRE

    Cassidy, M.

    2002-01-01

    AIM OF PRESENTATION: To compare a number of materials for extracoronal restoration of teeth with particular reference to CAD-CAM ceramics. CASE DESCRIPTION AND TREATMENT CARRIED OUT: This paper will be illustrated using clinical examples of patients treated using different ceramic restorations to present the advantages and disadvantages and each technique. The different requirements of tooth preparation, impression taking and technical procedures of each system will be presented and compar...

  10. Setting and genesis of uranium mineralization at Rexspar

    Energy Technology Data Exchange (ETDEWEB)

    Preto, V.A.

    1978-12-01

    The Rexspar uranium deposit is located approximately 5 kilometers south of Birch Island, B.C. Three separate zones of commercial-grade uranium mineralization mineable by open pit have been outlined. Uranium and fluorite-celestite mineralization occur in a trachytic member of alkali-feldspar porphyry, lithic tuff, tuff breccia and pyritic schist conformably interlayered with a succession of strongly deformed greenschists and fragmental rocks that are, in large part at least, of volcanic origin. The age of these strata is not precisely known, but they are considered as part of the possibly Mississippian Eagle Bay Formation. Commercial-grade uranium mineralization is always associated with fluorphlogopite-pyrite replacement of the trachytic unit and is contiguous to, but separate from, a zone of ore-grade fluorite mineralization. In all zones, ore occurs in lenses of variable thickness and lateral extent, which lie parallel to the schistosity of the trachytic rocks and surrounding greenschists. The principal radioactive minerals at Rexspar have been identified by other workers as uraninite, uranothorite, bastnaesite, torbernite and metatorbernite. Considerable amounts of thorium oxide and widespread rare earths have been reported from all three radioactive zones. The geology of the deposit suggests that the trachytic rocks represent a highly differentiated intrusive-extrusive system in which fluorphlogopite, pyrite, fluorite and uranium-bearing minerals were deposited late in the evolution of the system by deuteric, volatile-rich fluids. The considerable amounts of thorium and widespread rare earths associated with the uranium tend to support the thesis that this element is of primary origin rather than secondary.

  11. Transport and deposition of gold with uranium and platinum-group elements in unconformity-related uranium deposits

    International Nuclear Information System (INIS)

    The Jabiluka unconformity-related uranium deposit contains 8 million gms of gold (at an average grade of 10 gms/tonne) in addition to 207,000 tonnes U3O8 and significant palladium (at grades of up to 100 gms/tonne). Other uranium deposits of the Alligators Rivers Uranium Field, Northern Territory, Australia (Koongarra, Nabarlek) also contain traces of gold. The E1 Sherana and Rockhole deposits (South Alligator Valley, Northern Territory) produced minor gold during the nineteen fifties and the Coronation Hill gold palladium and platinum deposit (South Alligator Valley) was originally mined for uranium. It therefore appears that solutions which carry uranium are capable of transporting ore-forming amounts of gold and in some instances palladium and platinum, elements traditionally regarded as immobile. This paper presents evidence on the nature of the ore-forming solutions involved in mineralisation at the Jabiluka, Nabarlek and Koongarra deposits and examines possible transport and depositional mechanisms of U, Au and platinum group elements

  12. Clinical application of bio ceramics

    Science.gov (United States)

    Anu, Sharma; Gayatri, Sharma

    2016-05-01

    Ceramics are the inorganic crystalline material. These are used in various field such as biomedical, electrical, electronics, aerospace, automotive and optical etc. Bio ceramics are the one of the most active areas of research. Bio ceramics are the ceramics which are biocompatible. The unique properties of bio ceramics make them an attractive option for medical applications and offer some potential advantages over other materials. During the past three decades, a number of major advances have been made in the field of bio ceramics. This review focuses on the use of these materials in variety of clinical scenarios.

  13. Ceramic electrolyte coating and methods

    Science.gov (United States)

    Seabaugh, Matthew M.; Swartz, Scott L.; Dawson, William J.; McCormick, Buddy E.

    2007-08-28

    Aqueous coating slurries useful in depositing a dense coating of a ceramic electrolyte material (e.g., yttrium-stabilized zirconia) onto a porous substrate of a ceramic electrode material (e.g., lanthanum strontium manganite or nickel/zirconia) and processes for preparing an aqueous suspension of a ceramic electrolyte material and an aqueous spray coating slurry including a ceramic electrolyte material. The invention also includes processes for depositing an aqueous spray coating slurry including a ceramic electrolyte material onto pre-sintered, partially sintered, and unsintered ceramic substrates and products made by this process.

  14. Study of uranium plating measurement

    International Nuclear Information System (INIS)

    In neutron physics experiments, the measurement for plate-thickness of uranium can directly affect uncertainties of experiment results. To measure the plate-thickness of transform target (enriched uranium plating and depleted uranium plating), the back to back ionization chamber, small solid angle device and Au-Si surface barrier semi-conductor, were used in the experiment study. Also, the uncertainties in the experiment were analyzed. Because the inhomo-geneous of uranium lay of plate can quantitively affect the result, the homogeneity of uranium lay is checked, the experiment result reflects the homogeneity of uranium lay is good. (authors)

  15. Separation and recovery of molybdenum values from uranium process waste

    International Nuclear Information System (INIS)

    A method is described of recovering molybdenum and uranium values from a process waste generated from the production of nuclear-grade uranium hexafluoride which consists of: (a) hydrolysing the process waste which contains UF6, MoF6 and MoOF4 in an aqueous solution containing ammonium carbonate and ammonium hydroxide thereby forming ammonium uranyl carbonate; (b) digesting while maintaining a pH > 9, the resulting mother liquor at a temperature of about 600-800C. to evolve CO2 and convert the ammonium uranyl carbonate to solid ammonium diuranate; (c) filtering, washing and drying the solid ammonium diuranate

  16. Determination of low concentration of uranium in uranium amalgam

    International Nuclear Information System (INIS)

    Because of the strong interference in the determination of low concentrations of uranium in uranium amalgam by spectrophotometry, a new and rapid method has been developed for the removal of the interference of mercury(II) ion in the range of low uranium concentration by reducing Hg(II) to Hg in the sample dissolved in nitric acid with ascorbic acid. The separated uranium in the solution is determined by spectrophotometry in the concentration range of 0.25 approximately 5 mg/g uranium amalgam. The average error is about 2%. Very low concentrations of uranium (approximately 0.25 mg/g) in the uranium amalgam can be determined directly by fluorometric method. No interference effect has been observed at the mercury to uranium ratio up to 105; the average error is about 10%. (author)

  17. Drying of a tape-cast layer: Numerical modelling of the evaporation process in a graded/layered material

    DEFF Research Database (Denmark)

    Jabbaribehnam, Mirmasoud; Jambhekar, V. A.; Hattel, Jesper Henri;

    2016-01-01

    Evaporation of water from a ceramic layer is a key phenomenon in the drying process for the manufacturing of water-based tape cast ceramics. In this paper we present a coupled free-flow-porous-media model on the Representative Elementary Volume (REV) scale for coupling non-isothermal multi...... in accordance with the available results from the literature. We elaborate on and discuss the characteristic drying-rate curve for a single layer ceramic, and compare it with that of a graded/layered ceramic. We, moreover, show the influence of the mean diameter of particles of the porous medium (dp) — which...... directly affects the intrinsic permeability (K) based on the well-known Ergun's equation — of each single ceramic layer on the drying behaviour of a graded/layered ceramic....

  18. Designing functionally graded materials with superior load-bearing properties.

    Science.gov (United States)

    Zhang, Yu; Sun, Ming-Jie; Zhang, Denzil

    2012-03-01

    Ceramic prostheses often fail from fracture and wear. We hypothesize that these failures may be substantially mitigated by an appropriate grading of elastic modulus at the ceramic surface. In this study, we elucidate the effect of elastic modulus profile on the flexural damage resistance of functionally graded materials (FGMs), providing theoretical guidelines for designing FGMs with superior load-bearing property. The Young's modulus of the graded structure is assumed to vary in a power-law relation with a scaling exponent n; this is in accordance with experimental observations from our laboratory and elsewhere. Based on the theory for bending of graded beams, we examine the effect of n value and bulk-to-surface modulus ratio (E(b)/E(s)) on stress distribution through the graded layer. Theory predicts that a low exponent (0.15materials with various n values and E(b)/E(s) ratios can be fabricated by infiltrating alumina and zirconia with a low-modulus glass. Flexural tests show that graded alumina and zirconia with suitable values of these parameters exhibit superior load-bearing capacity, 20-50% higher than their homogeneous counterparts. Improving load-bearing capacity of ceramic materials could have broad impacts on biomedical, civil, structural, and an array of other engineering applications.

  19. Free vibration of symmetric and sigmoid functionally graded nanobeams

    Science.gov (United States)

    Hamed, M. A.; Eltaher, M. A.; Sadoun, A. M.; Almitani, K. H.

    2016-09-01

    The objective of this paper was the investigation of vibration characteristics of both nonlinear symmetric power and sigmoid functionally graded nonlocal nanobeams. The volume fractions of metal and ceramic are assumed to be distributed through a beam thickness by sigmoid law distribution and symmetric power function. Structures with symmetric distribution with mid-plane such as ceramic-metal-ceramic and metal-ceramic-metal are proposed. Nonlocal differential Eringen's elasticity is exploited to incorporate size dependency of nanobeam. The kinematic relations of Euler-Bernoulli beam are proposed, with the assumption of a small strain. A nonlocal equation of motion of nanobeam is derived by using principle of virtual work and then discretized by finite element method to obtain numerical solution. Numerical results show the effects of the function distribution, gradient index and nonlocal parameter on natural frequencies of macro- and nanobeam. This model is helpful in the mechanical design of nanoelectromechanical systems manufactured from FGM.

  20. Uranium hexafluoride handling

    International Nuclear Information System (INIS)

    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 UF6 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

  1. 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.

  2. Piezoelectric Ceramics and Their Applications

    Science.gov (United States)

    Flinn, I.

    1975-01-01

    Describes the piezoelectric effect in ceramics and presents a quantitative representation of this effect. Explains the processes involved in the manufacture of piezoelectric ceramics, the materials used, and the situations in which they are applied. (GS)

  3. Cooled Ceramic Turbine Vane Project

    Data.gov (United States)

    National Aeronautics and Space Administration — N&R Engineering will investigate the feasibility of cooled ceramics, such as ceramic matrix composite (CMC) turbine blade concepts that can decrease specific...

  4. Uranium markets after the hangover

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, H. (Hugh Douglas and Co. Ltd., San Francisco, CA (USA))

    1982-07-01

    A report is given on the current depressed state of the world's uranium markets and on the prospects for recovery. The impact on the uranium industry of low prices and reduced demand are outlined.

  5. International Uranium Resources Evaluation Project (IUREP) national favourability studies: Sweden

    International Nuclear Information System (INIS)

    Sweden, covers an area of approx. 450 000 square kilometers. It has a population of 8 millions. With few exceptions in the northern part the access can be regarded as good. A dense network of motorroads and railroad exists. The results obtained by the exploration works combined with other available geo-information permit a separation of two principal uranium provinces in Sweden. The first one is confined to sediments of Upper Cambrian and Lower Ordovician which appears in Southern Sweden and along the border of the Caledonian mountain range in Central Sweden. The uranium occurrence are stratiform, of blackshale type which occurs in the Peltura zone of Upper Cambrian or they are associated to a phosphatite-bearing unit of Lower Ordovician overlying the Cambrian shale formation. The distribution of uranium in Upper Cambrian rocks is in general dependant on their lithology which itself is related to the paleography. This conditions explain relatively higher uranium content of the shale from Billigen.The potential resources of the province are estimated at about 1 million tonnes uranium. The second uranium province, called Arjeplog-Arvidsjaur, situated immediately south of the Arctic circle, comprises one deposit - Pleutajokk - and a group of more than twenty occurrences of similar characteristics and age (1 700 - 1 800 my.). The results of the past exploration have shown that uranium is present in different types of rocks. Because of the presence of uranium in many of the pegmatites the possibility of the formation of large low grade deposits should be tested. Favourable areas are those regions where the geological conditions are similar to the geology of the Grenville province in Canada or the Damara belt of SW-Africa. Special studies are recommended on this subject

  6. Thermoluminescence dating of Brazilian indigenous ceramics

    International Nuclear Information System (INIS)

    Two indigenous ceramics fragments, one from Lagoa Queimada (LQ) and another from Barra dos Negros (BN), both sites located on Bahia state (Brazil), were dated by thermoluminescence (TL) method. Each fragment was physically prepared and divided into two fractions, one was used for TL measurement and the other for annual dose determination. The TL fraction was chemically treated, divided in sub samples and irradiated with several doses. The plot extrapolation from TL intensities as function of radiation dose enabled the determination of the accumulated dose (Dac), 3.99 Gy and 1.88 Gy for LQ and BN, respectively. The annual dose was obtained through the uranium, thorium and potassium determination by ICP-MS. The annual doses (D an) obtained were 2.86 and 2.26 mGy/year. The estimated ages were ∼1375 and 709 y for BN and LQ ceramics, respectively. The ages agreed with the archaeologists' estimation for the Aratu and Tupi tradition periods, respectively. (authors)

  7. Mechanical properties of ceramics

    CERN Document Server

    Pelleg, Joshua

    2014-01-01

    This book discusses the mechanical properties of ceramics and aims to provide both a solid background for undergraduate students, as well as serving as a text to bring practicing engineers up to date with the latest developments in this topic so they can use and apply these to their actual engineering work.  Generally, ceramics are made by moistening a mixture of clays, casting it into desired shapes and then firing it to a high temperature, a process known as 'vitrification'. The relatively late development of metallurgy was contingent on the availability of ceramics and the know-how to mold them into the appropriate forms. Because of the characteristics of ceramics, they offer great advantages over metals in specific applications in which hardness, wear resistance and chemical stability at high temperatures are essential. Clearly, modern ceramics manufacturing has come a long way from the early clay-processing fabrication method, and the last two decades have seen the development of sophisticated technique...

  8. Diffusion in ceramics

    CERN Document Server

    Pelleg, Joshua

    2016-01-01

    This textbook provides an introduction to changes that occur in solids such as ceramics, mainly at high temperatures, which are diffusion controlled, as well as presenting research data. Such changes are related to the kinetics of various reactions such as precipitation, oxidation and phase transformations, but are also related to some mechanical changes, such as creep. The book is composed of two parts, beginning with a look at the basics of diffusion according to Fick's Laws. Solutions of Fick’s second law for constant D, diffusion in grain boundaries and dislocations are presented along with a look at the atomistic approach for the random motion of atoms. In the second part, the author discusses diffusion in several technologically important ceramics. The ceramics selected are monolithic single phase ones, including: A12O3, SiC, MgO, ZrO2 and Si3N4. Of these, three refer to oxide ceramics (alumina, magnesia and zirconia). Carbide based ceramics are represented by the technologically very important Si-ca...

  9. Radioactive waste accumulations at non-uranium facilities as a potential source for uranium production

    International Nuclear Information System (INIS)

    radioactive elements occur occasionally: ores of noble, rare, colour and black metals within uranium provinces; mining-chemical materials (phosphorite, apatite, potassium salt, mica, feldspar, brines, mineral waters); drinking and technical water; construction materials of by production. The allocation of obviously pure and radioactive free resources is difficult as radionuclides can mobilize under certain conditions in deposits and sites with below clarke grades. Three types of products and wastes from non-radioactive resources are determined basing on their environmental influence: I. Most dangerous containing easy leachable uranium forms and radon; II. Medium danger containing mobile chemical compounds of Th and 40E; III. Rather safe containing isomorphic thorium and uranium admixtures in non-radioactive minerals and thorium minerals refractory to oxidation. Summarizing and systematization of above information provides proper organization of environmental activities during non-radioactive resources mining, production and waste management

  10. Uranium resources, production and demand

    International Nuclear Information System (INIS)

    Nuclear power-generating capacity will continue to expand, albeit at a slower pace than during the past fifteen years. This expansion must be matched by an adequately increasing supply of uranium. This report compares uranium supply and demand data in free market countries with the nuclear industry's natural uranium requirements up to the year 2000. It also reviews the status of uranium exploration, resources and production in 46 countries

  11. The Toxicity of Depleted Uranium

    OpenAIRE

    Wayne Briner

    2010-01-01

    Depleted uranium (DU) is an emerging environmental pollutant that is introduced into the environment primarily by military activity. While depleted uranium is less radioactive than natural uranium, it still retains all the chemical toxicity associated with the original element. In large doses the kidney is the target organ for the acute chemical toxicity of this metal, producing potentially lethal tubular necrosis. In contrast, chronic low dose exposure to depleted uranium may not produce a c...

  12. Radiation damage of metal uranium

    International Nuclear Information System (INIS)

    This report is concerned with the role of dispersion second phase in uranium and burnup rate. The role of dispersion phases in radiation stability of metal uranium was studies by three methods: variation of electric conductivity dependent on the neutron flux and temperature of pure uranium for different states of dispersion second phase; influence of dispersion phase on the radiation creep; transmission electron microscopy of fresh and irradiated uranium

  13. Nuclear-grade gadolinium oxide (Gd2O3) powder

    International Nuclear Information System (INIS)

    The specification covers the minimum chemical and physical characteristics of nuclear-grade gadolinium oxide powder intended for subsequent processing for use in nuclear fuel application, for example, as an addition to uranium dioxide. The specification includes a description of chemical and physical requirements, cleanliness, quality control, inspection, certification, rejection, packaging, and shipping

  14. Uranium extraction technology

    International Nuclear Information System (INIS)

    In 1983 the Nuclear Energy Agency of the Organisation for Economic Co-operation and Development (OECD/NEA) and the IAEA jointly published a book on Uranium Extraction Technology. A primary objective of this report was to document the significant technological developments that took place during the 1970s. The purpose of this present publication is to update and expand the original book. It includes background information about the principle of the unit operations used in uranium ore processing and summarizes the current state of the art. The publication also seeks to preserve the technology and the operating 'know-how' developed over the past ten years. This publication is one of a series of Technical Reports on uranium ore processing that have been prepared by the Division of Nuclear Fuel Cycle and Waste Management at the IAEA. A complete list of these reports is included as an addendum. Refs, figs and tabs

  15. The Kintyre uranium project

    International Nuclear Information System (INIS)

    The Kintyre Uranium Project is being developed by Canning Resources Pty Ltd, a subsidiary of Rio Tinto (formerly CRA). The work on the project includes the planning and management of a number of background environmental studies. The company has also commissioned studies by external consultants into process technologies, mining strategies and techniques for extracting the uranium ore from the waste rock. In addition, Canning Resources has made a detailed assessment of the worldwide market potential for Australian uranium in the late 1990s and into the 21st century. The most significant factor affecting the future of this project is the current product price. This price is insufficient to justify the necessary investment to bring this project into production

  16. Therapy of uranium contaminations

    International Nuclear Information System (INIS)

    Renal risks associated with the use of chelating agent as a treatment for acute uranium contamination were investigated. Rats were given a single intramuscular injection of uranyl nitrate solution. The percentage of renal uptake of uranyl nitrate as a function of the quantity injected was measured. Then the effect of a single DTPA intraperitoneal injection and the effect of a single bicarbonate injection on renal uptake of uranyl nitrate were studied. The preliminary results were as follows: constancy of renal uptake of uranyl nitrate (13 to 20% of the quantity injected); harmlessness of DTPA as a treatment for uranium contamination (DTPA does not increase uranium renal burden); inefficacy of bicarbonates on uranyl renal uptake

  17. Sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    World-class sandstone-type uranium deposits are defined as epigenetic concentrations of uranium minerals occurring as uneven impregnations and minor massive replacements primarily in fluvial, lacustrine, and deltaic sandstone formations. The main purpose of this introductory paper is to define, classify, and introduce to the general geologic setting for sandstone-type uranium deposits

  18. Uranium resources, demand and production

    International Nuclear Information System (INIS)

    Estimations of the demand and production of principal uranium resource categories are presented. The estimations based on data analysis made by a joint 'NEA/IAEA Working Party on Uranium Resources' and the corresponding results are published by the OECD (Organization for Economic Co-operation and Development) in the 'Uranium Resources, Production and Demand' Known as 'Red Book'. (M.C.K.)

  19. Assessment of ceramic membrane filters

    Energy Technology Data Exchange (ETDEWEB)

    Ahluwalia, R.K.; Geyer, H.K.; Im, K.H. [and others

    1995-08-01

    The objectives of this project include the development of analytical models for evaluating the fluid mechanics of membrane coated, dead-end ceramic filters, and to determine the effects of thermal and thermo-chemical aging on the material properties of emerging ceramic hot gas filters. A honeycomb cordierite monolith with a thin ceramic coating and a rigid candle filter were evaluated.

  20. The uranium International trade

    International Nuclear Information System (INIS)

    The aim of this thesis is the understanding of how the present dynamic of uranium International trade is developed, the variables which fall into, the factors that are affecting and conditioning it, in order to clarify which are going to be the outlook in the future of this important resource in front of the present ecological situation and the energetic panorama of XXI Century. For this purpose, as starting point, the uranium is considered as a strategic material which importance take root in its energetic potential as alternate energy source, and for this reason in Chapter I, the general problem of raw materials, its classification and present situation in the global market is presented. In Chapter II, by means of a historical review, is explain what uranium is, how it was discovered, and how since the end of the past Century and during the last three decades of present, uranium pass of practically unknown element, to the position of a strategic raw material, which by degrees, generate an International market, owing to its utilization as a basic resource in the generation of energy. Chapter III, introduce us in the roll played by uranium, since its warlike applications until its utilization in nuclear reactors for the generation of electricity. Also is explain the reason for this change in the perception at global level. Finally, in Chapter IV we enter upon specifically in the present conditions of the International market of this mineral throughout the trends of supply and demand, the main producers, users, price dynamics, and the correlation among these economical variables and other factors of political, social and ecological nature. All of these with the purpose to found out, if there exist, a meaning of the puzzle that seems to be the uranium International trade

  1. Ceramic vane drive joint

    Science.gov (United States)

    Smale, Charles H. (Inventor)

    1981-01-01

    A variable geometry gas turbine has an array of ceramic composition vanes positioned by an actuating ring coupled through a plurality of circumferentially spaced turbine vane levers to the outer end of a metallic vane drive shaft at each of the ceramic vanes. Each of the ceramic vanes has an end slot of bow tie configuration including flared end segments and a center slot therebetween. Each of the vane drive shafts has a cross head with ends thereof spaced with respect to the sides of the end slot to define clearance for free expansion of the cross head with respect to the vane and the cross head being configured to uniformly distribute drive loads across bearing surfaces of the vane slot.

  2. Effect of mineral constituents in the bioleaching of uranium from uraniferous sedimentary rock samples, Southwestern Sinai, Egypt

    International Nuclear Information System (INIS)

    Bioleaching, like Biotechnology uses microorganisms to extract metals from their ore materials, whereas microbial activity has an appreciable effect on the dissolution of toxic metals and radionuclides. Bioleaching of uranium was carried out with isolated fungi from uraniferous sedimentary rocks from Southwestern Sinai, Egypt. Eight fungal species were isolated from different grades of uraniferous samples. The bio-dissolution experiments showed that Aspergillus niger and Aspergillus terreus exhibited the highest leaching efficiencies of uranium from the studied samples. Through monitoring the bio-dissolution process, the uranium grade and mineralogic constituents of the ore material proved to play an important role in the bioleaching process. The tested samples asserted that the optimum conditions of uranium leaching are: 7 days incubation time, 3% pulp density, 30 °C incubation temperature and pH 3. Both fungi produced the organic acids, namely; oxalic, acetic, citric, formic, malonic, galic and ascorbic in the culture filtrate, indicating an important role in the bioleaching processes. - Highlights: • Aspergillus niger and Aspergillus terreus are the only isolates achieved highest leaching efficiency of uranium from the studied samples. • Bioleaching process directly related to variations in mineral constituents and uranium grades. • The optimum conditions of uranium bioleaching from its ores, were found to be 7 days, 3% pulp density, pH 3 and 30 °C. • A. niger and A. terreus organic acids play an important and effective role for uranium leaching process

  3. Chemwes Uranium Plant

    International Nuclear Information System (INIS)

    The Chemwes Uranium Plant is located in an area which is underlain to a major extent by pinnacled dolomite. It was decided to adopt a replacement fill for support of light structures in preference to alternatives such as the installation of piles or 'bridging' between pinnacles. The 3 m thick soil 'raft' resulting from the fill replacement technique made it possible to support all but a very small number of foundations upon shallow spread footings or raft slabs. This article describes a replacement fill for support of light structures at the Chemwes Uranium Plant

  4. Corrosion-resistant uranium

    Science.gov (United States)

    Hovis, V.M. Jr.; Pullen, W.C.; Kollie, T.G.; Bell, R.T.

    1981-10-21

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  5. Preparation of Uranium Dioxide by Electrochemical Reduction in Ammonium Carbonate Solutions and Subsequent Precipitation

    International Nuclear Information System (INIS)

    Experiments in a small scale electrolysis cell on cathodic reduction of uranium (VI) to uranium (IV) show the possibility of an efficient way to obtain uranium (IV) in carbonate solutions. From this solution uranium (IV) hydrous oxide precipitates by merely raising the temperature. To obtain larger quantities of material needed for technological testing, a scale-up of the process was attempted. An electrolysis cell of hard PVC (polyvinylchloride) was constructed with a mercury pool cathode of approximately 2.5 dm2 and platinum anodes. The catholyte was separated from the anolyte by cationexchange membranes. The catholyte was circulated between two 50-1 reservoirs and streamed toward the vigorously stirred mercury cathode. The working potential of mercury was controlled against an Ag/AgCl/KC1 (sat.) reference electrode, the potential being held constant at -1.5 V. The current efficiency is approximately 90%; the power consumed for the reduction process is about 0.8 kWh/kg of uranium dioxide. After the electrolysis was completed the precipitation was initiated only by heating the deeply green clear solution up to 70 deg. C in a separate all-glass vessel of 60-1 volume. From 50, 1 of the catholyte solution 1 kg of a centrifuged product (containing about 20% of water) was obtained. The coulometric analysis of the oxygen-uranium ratio always gave results in the range of 2.04 to 2.09. By the procedure described uranium (IV) hydrous oxide is selectively precipitated, and the oxygen-uranium ratio in the precipitate was found to be independent of the degree of completion of the reduction. The product was identified as the alpha phase of uranium dioxide by the X-ray powder diffraction. Experiments in sintering and characterization of uranium dioxide thus obtained for the ceramic nuclear fuel requirements are under way. (author)

  6. Supported microporous ceramic membranes

    Science.gov (United States)

    Webster, E.; Anderson, M.

    1993-12-14

    A method for the formation of microporous ceramic membranes onto a porous support includes placing a colloidal suspension of metal or metal oxide particles on one side of the porous support and exposing the other side of the porous support to a drying stream of gas or a reactive gas stream so that the particles are deposited on the drying side of the support as a gel. The gel so deposited can be sintered to form a supported ceramic membrane useful for ultrafiltration, reverse osmosis, or molecular sieving having mean pore sizes less than 100 Angstroms. 4 figures.

  7. Market stresses and readjustment: politics and pragmatism in the international uranium market

    International Nuclear Information System (INIS)

    Historically, the United States uranium market was isolated from international markets; therefore, United States consumers had little incentive to look abroad. Later, the government imposed an embargo on imports of uranium for domestic use. The phase-out of the embargo and recent discovery of high-grade deposits in Australia and Western Canada, as well as large intermediate-cost deposits in Africa, assure that the United States market will be affected by international developments more than in the past. Projected uranium-consumer supply arrangements are compared with enrichment commitments to reactor requirements for several key countries. For all areas, both uranium supply and enrichment commitments exceed reactor needs until at least 1985. Inventory buildup will depend upon what adjustments are made. Uranium prices have never been set by market forces alone and governmental policies and political struggles may have a significant impact on price. 8 figures

  8. Determination of carbon in ceramic oxides - Al sub(2)O sub(3) and UO sub(2)

    International Nuclear Information System (INIS)

    Carbon determination in ceramics oxides is the objective of the present work. The amount of carbon in aluminium oxide (Al sub(2)O sub(3)) and uranium oxide (UO sub(2)) is determined by fusion/infrared cell technique. A carbon determinator (IECO - CS244) was used to test the performance of the analytical results. The determinator was calibrated using steel standards instead of ceramics oxides, and a special flux mix (W, Sn and Fe) was used. The details of the analysis technique and the data obtained are discussed. (author)

  9. Uranium sorption by tannin resins

    International Nuclear Information System (INIS)

    The sorption of uranium by immobilised Eucalyptus Saligna Sm. and Lysiloma latisiliqua L tannins was investigated. Immobilization condition were analyzed. These resins resulted suitable adsorbent for the concentration of uranium from aqueous systems. The sorption of uranium is pH dependent. At pH 5.5 maximum in sorption capacity is registered. The presence of appreciable amount of sodium chloride do not have any effect on uranium removal. Carbonate and calcium ions in concentrations similar to these that could be found in sea water and other natural water do not decrease the uranium uptake. Tannin resins can be used several times without an appreciable decay of their sorption capacity

  10. Uranium mineralization in fluviatile facies

    International Nuclear Information System (INIS)

    Over half the world's known uranium reserves occur in fluviatile rocks. These deposits include Archean quartz-pebble conglomerates of alluvial fan facies and arkosic braided and meandering fluviatile sandstone facies. Uranium-bearing quartz-pebble conglomerates are described. Approximately 40% of the world's uranium reserves have been found in epigenetic sandstone deposits. Deposits of uranium in braided or meandering fluviatile sandstones can be grouped into peneconcordant and roll-front types. Uranium deposits are widely distributed through central, northern and western Australia but only a very small proportion of the reserves occur in fluviatile sequences

  11. Estimation of potential uranium resources

    International Nuclear Information System (INIS)

    Potential estimates, like reserves, are limited by the information on hand at the time and are not intended to indicate the ultimate resources. Potential estimates are based on geologic judgement, so their reliability is dependent on the quality and extent of geologic knowledge. Reliability differs for each of the three potential resource classes. It is greatest for probable potential resources because of the greater knowledge base resulting from the advanced stage of exploration and development in established producing districts where most of the resources in this class are located. Reliability is least for speculative potential resources because no significant deposits are known, and favorability is inferred from limited geologic data. Estimates of potential resources are revised as new geologic concepts are postulated, as new types of uranium ore bodies are discovered, and as improved geophysical and geochemical techniques are developed and applied. Advances in technology that permit the exploitation of deep or low-grade deposits, or the processing of ores of previously uneconomic metallurgical types, also will affect the estimates

  12. ICP-MS determination of rare earth elements and thorium in uranium-rich geological samples

    International Nuclear Information System (INIS)

    Uranium is the key fuel element in the field of nuclear energy. Hence, it often becomes necessary to determine trace constituents in a variety of uranium-rich samples like uranium concentrates and reactor fuel grade samples as well as in geological samples. Solution inductively coupled plasma mass spectrometry (ICP-MS) has emerged as a powerful and sensitive technique that has been successfully used for accurate direct determination of trace elements in geological materials. But, even with ICP-MS, direct determination of trace constituents in uranium-rich geological materials is extremely difficult because of the high levels of total dissolved salts (TDS) and space charge effects arising from the heavy uranium matrix. Therefore, in the present work, the extent of signal suppression on all rare-earth elements and yttrium due to the uranium matrix has been studied at a single set of operating conditions for different amounts of uranium taken and the tolerance limits have been evaluated. Significant space charge effects on the rare-earth elements and yttrium were observed. Extending the studies to some real samples, selected uranium-rich samples were analysed by ICP-MS in the presence of uranium matrix as well as after solid phase extraction separation of the uranium matrix using activated carbon as sorbent in fluoride medium. The values were in good agreement since the uranium levels in the sample solutions aspirated into the plasma were kept below 50 μg/mL by applying appropriate dilution. Sample solutions of two uraninite mineral samples were also analysed after removal of the major uranium matrix. The values obtained by ICP-MS were in good agreement with those reported using inductively coupled plasma optical emission spectrometry (ICP-OES). (author)

  13. Spent fuel characteristics analysis for thorium-uranium breeding recycle in PWRs

    International Nuclear Information System (INIS)

    Spent fuel characteristics analyses of thorium-based fuel were investigated using ORIGEN-S code compared with uranium-based fuel. Such parameters as radio- activity, radiotoxicity, decay heat, and gamma ray were considered. Relative results in this work could provide some reference information for storage, reprocessing and disposal of thorium-based spent fuel. Four type fuels, thorium-based fuel U3ThOX (mixed reactor grade 233U-thorium oxide), PuThOX (mixed reactor grade plutonium-thorium oxide), uranium-based fuel UOX (uranium oxide) and MOX (mixed reactor grade plutonium-uranium oxide), on the basis of core designs for thorium-uranium breeding recycle in PWRs were investigated. The calculated results show that: 1) Due to extremely low content of transuranic nuclides, the radiotoxicity of U3ThOX is dramatically lower than that of three other types of spent fuel in 1000 years after discharge; 2) In thorium-based spent fuel the intensity of gamma ray near 2.6 MeV mainly generated by 208Tl in 232U decay chain is much stronger than that in uranium-based fuel. The intensity of γ ray near 2.6 MeV reaches a local peak in about 10 years after discharge when the reprocessing should not be performed for thorium-based spent fuel. (authors)

  14. Phase separation kinetic studies for uranium recovery from phosphoric acid by solvent extraction

    International Nuclear Information System (INIS)

    Wet process phosphoric acid (WPA) contains uranium in the range 80-120 mg/LU3O8 while in the Merchant Grade Acid (MGA) it is in the range 220-240 mg/L .Based on the experimental work, a two cycle solvent extraction process for uranium separation from phosphoric acid has been developed at REDS and patented. While the equilibrium extraction behaviour and reaction mechanisms have been studied, the kinetic aspect of uranium extraction from phosphoric acid with particular reference to rate of mass transfer and phase disengagement time has not been studied

  15. Diffusion of uranium hexafluoride

    Science.gov (United States)

    Winkelmann, J.

    This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of uranium hexafluoride

  16. Hydrolysis of uranium hexafluoride

    International Nuclear Information System (INIS)

    A literature survey is presented of uranium hexafluoride hydrolysis methods as the first step in UF6 conversion to UO2. Reviewed are early methods of hydrolysis, the hydrolysis by dry water vapour, the fluidized-bed method, and the liquid phase hydrolysis of UF6 gas. (J.P.)

  17. Uranium recovery process

    International Nuclear Information System (INIS)

    A process of recovering uranium from an aqueous medium containing both it and sulfuric acid which comprises contacting the medium with an anion exchange resin having tertiary amine groups, said resin being the product of (a) the reaction of polyethyleneimine and a dihaloalkane and (b) the subsequent reductive alkylation of the product of (a)

  18. 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.

  19. Uranium prospection in Venezuela

    International Nuclear Information System (INIS)

    Full text: The worldwide increase of energy consumption and high fossil fuels costs generates the necessity of alternative energy sources. At present, nuclear energy is substituting the use of hydrocarbons, due to its high performance and contribution to environmental preservation, since it avoids the emission of greenhouse gases. Uranium consumer countries will continue to increase its demand, and even, is expected the incorporation of new reactors in countries with emerging economies. Base in the statement considered above, investment in new mineral deposit is justified. At present, some countries are motivated to start or continue the uranium exploration because of the evolution of the nuclear energy industry. Venezuela started exploration in the mid of 1970s, and stopped at 1980s. Our purpose is to evaluate uranium resources potential in the country, both for own use or export. In order to locate potential areas for exploration, in this initial phase all data from previous period is being compiled, incorporating information from oil exploration (seismic data, wells profiles, etc.). This information is been digitalized to generate a database into a geographical information system. Preliminary results show three areas of interest, where new geological, geochemical and geophysical surveys are propose. At this time, we do not have specific information about ore reserves, but we have anomalous areas that have been established as starting points to continue the uranium exploration in the country. (author)

  20. Uranium: The recalcitrant commodity

    International Nuclear Information System (INIS)

    The uranium is analysed as a special market commodity and compared with other metals like copper. The supply-demand balance, production costs and the special form of pricing are discussed. The likely evaluation of inventories and the future capacity utilization are also discussed and commented. (author). 2 refs, 8 figs

  1. Uranium and nuclear issues

    International Nuclear Information System (INIS)

    This seminar focussed on the major issues affecting the future of the entire nuclear fuel cycle. In particular it covered issues bearing on the formation of public policy in relation to the use of uranium as an energy source: economic risk, industrial risks, health effects, site selection, environmental issues, and public acceptance

  2. Swelling of Uranium

    International Nuclear Information System (INIS)

    An understanding of the mechanism of swelling in irradiated uranium has been handicapped by lack of data from experiments in which the parameters are accurately known. The present- concepts of swelling are based largely on data of this nature. In this study, uranium specimens with less than 0,01% impurity were irradiated below 300°C, and the swelling was induced by subsequent heat treatment outside the reactor where careful control of the temperature was possible. The results obtained by this technique were self'consistent but in considerable disagreement with rhe results of the in-pile investigations. The density and porosity of irradiated uranium specimens were determined following pulse annealing in the alpha, beta and gamma phases« Both the light microscope and the electron microscope were used to study porosity. The results may be summarized as follows: (1) Uranium specimens irradiated to 0.30%bum-up and heat-treated 75 h at temperatures less than 550°C in the α-phase swelled less than 1%. (2) Uranium specimens (0.30% bum-up) heat-treated 75 h at temperatures between 550°C and 650°C in the α- phase swelled up to 18%. This swelling was due to bubbles with diameters up to 15/μm. These results were diametrically opposed to recent data. (3) Uranium specimens (0.30% bum-up) heat-treated 75 h at temperatures in the ß-phase decreased their density by 4- 5%. This decrease in density is apparently the result of grain-boundary cracking rather than bubble formation, as there is evidence to suggest that fission gas is retained in the matrix of the γ-phase. These results suggest that a modification of the role of pressure and surface tension is required in the current theories of swelling. (4) A uranium specimen (0.30% bum- up) heat-treated for 15 h in the γ-phase at 820°C swelled 20%. In this case the swelling was primarily due to the formation of bubbles in the vicinity of and on grain boundaries. The explanation of these experimental results requires

  3. Statistic><Ceramics

    DEFF Research Database (Denmark)

    Hansen, Flemming Tvede

    2008-01-01

    Co-organizer for and participant at the exhibition: Statistic><Ceramics The Röhsska Museum of Design and Decorative Arts; Gothenborg 5/2-16/3 2008 Museum fur Kunst und Gewerbe, Hamburg 3/4-27/4 2008...

  4. Kvanefjeld uranium project

    International Nuclear Information System (INIS)

    The draft uranium project ''Kvanefjeld'' describes the establishment and operation of an industrial plant for exploiting the uranium deposit at Kvanefjeld. The draft project is part of the overall pre-feasibility project and is based on its results. The draft project includes two alternative locations for the processing plant and the tailings deposit plant. The ore reserve is estimated at 56 million tons with an average content of 365 PPM. The mine will be established as an open pit, with a slope angle of 55deg. Conventional techniques are used in drilling, blasting and handling the ore. Waste rock with no uranium content will be disposed of in two ponds near the mine. The waste rock volume is estimated at 80 million tons. A processing plant for extracting uranium from the ore will be established. The technical layout of the plant is based on the extraction experiments performed at Risoe from 1981-83. Yearly capacity is 4.2 million tons of ore. Electrical energy will be supplied from a hydroelectric station to be built at Johan Dahl Land. Thermal energy (steam/heat) will be supplied from a coal-fired district heating plant to be built in connection with the processing plant. Expected power consumption is estimated at 225 GWh/year. Heat consumption is of the same order. In the third year the plant is expected to operate at full capacity. Operating costs will be Dkr. 121/ton of ore from years 1 through 7. Consumption of chemicals will be reduced from the 7th year, and operating costs will consequently drop to Dkr. 115/ton of ore. Calculations show that industrial extraction of the uranium deposit in Kvanefjeld is economically advantageous. In addition, the economy of the project is expected to improve by extracting byproducts from the ore. (EG)

  5. Uranium from seawater

    International Nuclear Information System (INIS)

    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 105, 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 103 in seawater instead of the reported values of 105. 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 105 in fresh water. However, the system was not tested in seawater

  6. 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.

  7. Glass- and ceramic-grade feldspar from waste

    OpenAIRE

    Mitchell, C J; Evans, E J

    1996-01-01

    In a typical feldspar operation extraction and size reduction may account for 20 to 25% of operating costs. Production of feldspar from feldspathic quarry fines and / or mine tailings would avoid this cost as the material has already been extracted and crushed. Other benefits arise from a reduction in waste treatment and disposal, an increase in the revenue realised per tonne of material extracted and, ultimately, an environmental benefit from a reduction in feldspar mined. Feldspathic wa...

  8. Status of plutonium ceramic immobilization processes and immobilization forms

    Energy Technology Data Exchange (ETDEWEB)

    Ebbinghaus, B.B.; Van Konynenburg, R.A. [Lawrence Livermore National Lab., CA (United States); Vance, E.R.; Jostsons, A. [Australian Nuclear Science and Technology Organization, Menai (Australia)] [and others

    1996-05-01

    Immobilization in a ceramic followed by permanent emplacement in a repository or borehole is one of the alternatives currently being considered by the Fissile Materials Disposition Program for the ultimate disposal of excess weapons-grade plutonium. To make Pu recovery more difficult, radioactive cesium may also be incorporated into the immobilization form. Valuable data are already available for ceramics form R&D efforts to immobilize high-level and mixed wastes. Ceramics have a high capacity for actinides, cesium, and some neutron absorbers. A unique characteristic of ceramics is the existence of mineral analogues found in nature that have demonstrated actinide immobilization over geologic time periods. The ceramic form currently being considered for plutonium disposition is a synthetic rock (SYNROC) material composed primarily of zirconolite (CaZrTi{sub 2}O{sub 7}), the desired actinide host phase, with lesser amounts of hollandite (BaAl{sub 2}Ti{sub 6}O{sub 16}) and rutile (TiO{sub 2}). Alternative actinide host phases are also being considered. These include pyrochlore (Gd{sub 2}Ti{sub 2}O{sub 7}), zircon (ZrSiO{sub 4}), and monazite (CePO{sub 4}), to name a few of the most promising. R&D activities to address important technical issues are discussed. Primarily these include moderate scale hot press fabrications with plutonium, direct loading of PuO{sub 2} powder, cold press and sinter fabrication methods, and immobilization form formulation issues.

  9. Design Study for a Low-Enriched Uranium Core for the High Flux Isotope Reactor, Annual report for FY 2009

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, David [ORNL; Freels, James D [ORNL; Ilas, Germina [ORNL; Miller, James Henry [ORNL; Primm, Trent [ORNL; Sease, John D [ORNL; Guida, Tracey [University of Pittsburgh; Jolly, Brian C [ORNL

    2010-02-01

    This report documents progress made during FY 2009 in studies of converting the High Flux Isotope Reactor (HFIR) from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum alloy. With axial and radial grading of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in reactor performance from the current level. Results of selected benchmark studies imply that calculations of LEU performance are accurate. Studies are reported of the application of a silicon coating to surrogates for spheres of uranium-molybdenum alloy. A discussion of difficulties with preparing a fuel specification for the uranium-molybdenum alloy is provided. A description of the progress in developing a finite element thermal hydraulics model of the LEU core is provided.

  10. Graded plasma spraying of premixed metalceramic powders on metallic substrates

    Science.gov (United States)

    Lima, C. R. C.; Trevisan, R.-E.

    1997-06-01

    The mismatch between the thermal expansion coefficients of ceramics and metals and the differential stresses it causes at the interface create problems in metal to ceramic joining. Research has been con-ducted to solve this problem in thermal barrier coating technology. Previous studies have considered met-al-ceramic multilayers or graded-coatings, which include a metallic bond coat. In this study, a graded plasma-sprayed metal-ceramic coating is developed using the deposition of premixed metal and ceramic powders without the conventional metallic bond coat. Influences of thickness variations, number, and composition of the layers are investigated. Coatings are prepared by atmospheric plasma-spraying on In-conel 718 superalloy substrates. Ni-Cr-Al and ZrO2 -8 % Y2O3 powders are used for plasma spraying. Ad-hesive and cohesive strength of the coatings are determined. The concentration profile of the elements is determined by x-ray energy-dispersive analysis. The microstructure and morphology of the coatings are investigated by optical and scanning electron microscopy (SEM). Results show that the mixed metal-ce-ramic coating obtained with the deposition of premixed powders is homogeneous. The morphology and microstructure of the coatings are considered satisfactory.

  11. Ceramic tubesheet design analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mallett, R.H.; Swindeman, R.W.

    1996-06-01

    A transport combustor is being commissioned at the Southern Services facility in Wilsonville, Alabama to provide a gaseous product for the assessment of hot-gas filtering systems. One of the barrier filters incorporates a ceramic tubesheet to support candle filters. The ceramic tubesheet, designed and manufactured by Industrial Filter and Pump Manufacturing Company (EF&PM), is unique and offers distinct advantages over metallic systems in terms of density, resistance to corrosion, and resistance to creep at operating temperatures above 815{degrees}C (1500{degrees}F). Nevertheless, the operational requirements of the ceramic tubesheet are severe. The tubesheet is almost 1.5 m in (55 in.) in diameter, has many penetrations, and must support the weight of the ceramic filters, coal ash accumulation, and a pressure drop (one atmosphere). Further, thermal stresses related to steady state and transient conditions will occur. To gain a better understanding of the structural performance limitations, a contract was placed with Mallett Technology, Inc. to perform a thermal and structural analysis of the tubesheet design. The design analysis specification and a preliminary design analysis were completed in the early part of 1995. The analyses indicated that modifications to the design were necessary to reduce thermal stress, and it was necessary to complete the redesign before the final thermal/mechanical analysis could be undertaken. The preliminary analysis identified the need to confirm that the physical and mechanical properties data used in the design were representative of the material in the tubesheet. Subsequently, few exploratory tests were performed at ORNL to evaluate the ceramic structural material.

  12. Ceramic Laser Materials

    Energy Technology Data Exchange (ETDEWEB)

    Soules, T F; Clapsaddle, B J; Landingham, R L; Schaffers, K I

    2005-02-15

    Transparent ceramic materials have several major advantages over single crystals in laser applications, not the least of which is the ability to make large aperture parts in a robust manufacturing process. After more than a decade of working on making transparent YAG:Nd, Japanese workers have recently succeeded in demonstrating samples that performed as laser gain media as well as their single crystal counterparts. Since then several laser materials have been made and evaluated. For these reasons, developing ceramic laser materials is the most exciting and futuristic materials topic in today's major solid-state laser conferences. We have established a good working relationship with Konoshima Ltd., the Japanese producer of the best ceramic laser materials, and have procured and evaluated slabs designed by us for use in our high-powered SSHCL. Our measurements indicate that these materials will work in the SSHCL, and we have nearly completed retrofitting the SSHCL with four of the largest transparent ceramic YAG:Nd slabs in existence. We have also begun our own effort to make this material and have produced samples with various degrees of transparency/translucency. We are in the process of carrying out an extensive design-of-experiments to establish the significant process variables for making transparent YAG. Finally because transparent ceramics afford much greater flexibility in the design of lasers, we have been exploring the potential for much larger apertures, new materials, for example for the Mercury laser, other designs for SSHL, such as, edge pumping designs, slabs with built in ASE suppression, etc. This work has just beginning.

  13. Current developments in uranium exploration activities in Egypt

    International Nuclear Information System (INIS)

    Current developments in uranium exploration activities since 1993 are summarized, with a brief history of uranium exploration in Egypt. New target for these exploration activities are also outlined. Previous exploration techniques used were: airborne radiometric and magnetic surveys, ground radiometric surveys, regional and detailed geologic mapping, exploratory mining works at the Wadi level, limited diamond drilling, as well as all supplementary laboratory works. Most of these activities were concentrated on the Eastern Desert terrains, particularly in granitic rocks. Main discoveries are four uranium occurrences in Pan African younger granites in addition to one at the contact of bostonite and felsite dykes in metasediments and one in psammitic gneisses in the Eastern Desert, as well as one in siltstone in a Paleozoic sedimentary basin within granitic rocks in Sinai. Two new activities are now underway: exploratory drilling programs in the uranium occurrences in the Eastern Desert and Sinai with newly acquired equipment, and experimental heap leaching of the low grade uranium ores at the site. In addition, some other techniques have been strengthened and updated such as well logging, airborne spectrometric surveys and ground geophysical surveys. Exploration activities have been recently directed also to new target areas in sedimentary formations and intracratonic sedimentary basins. The possibility of the occurrence of unconformity related deposits are also considered. (author). 8 refs, 9 figs

  14. Towards a Model for Albitite-Type Uranium

    Directory of Open Access Journals (Sweden)

    Andy Wilde

    2013-01-01

    Full Text Available Albitite-type uranium deposits are widely distributed, usually of low grade (<1% U3O8, but are often large and collectively contain over 1 million tonnes of U3O8. Uranium is hosted in a wide range of metamorphic lithologies, whose only common characteristic is that they have been extensively mylonitised. Ore minerals are disseminated and rarely in megascopic veins, within and adjacent to albitised mylonites. Grain size is uniformly fine, generally less than 50 microns. Scanning electron microscopy reveals that spatial association between uranium and various Ti-bearing phases is common. Gangue minerals include albite, carbonates (calcite and dolomite, and sodic pyroxene and amphibole. The ore rarely contains economic metals apart from uranium, phosphorous at Itataia being an exception. There is widespread evidence of hydrothermal zirconium mobility and hydrothermal zircon and other Zr phases are frequent and in some cases abundant gangue minerals. Positive correlations are noted between uranium and various high field strength elements. The group remains poorly described and understood, but a link to iron-oxide copper-gold (IOCG deposits and/or carbonatite and/or alkaline magmatism is plausible.

  15. Recovery of uranium from uranium refining waste water by using immobilized persimmon tannin

    International Nuclear Information System (INIS)

    Some attempts were made to examine the practical conditions for uranium recovery from uranium refining waste water. The adsorbent was highly effective in recovering uranium. The uranium adsorption was affected by pH, temperature, and uranium concentration of the uranium refining waste water. The adsorbent also recovered uranium effectively in column system. It aquires better mechanical properties and can be used repeatedly in the uranium adsorption-desorption cycles. (author)

  16. 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...

  17. Method of preparation of uranium nitride

    Science.gov (United States)

    Kiplinger, Jaqueline Loetsch; Thomson, Robert Kenneth James

    2013-07-09

    Method for producing terminal uranium nitride complexes comprising providing a suitable starting material comprising uranium; oxidizing the starting material with a suitable oxidant to produce one or more uranium(IV)-azide complexes; and, sufficiently irradiating the uranium(IV)-azide complexes to produce the terminal uranium nitride complexes.

  18. Uranium Potential and Regional Metallogeny in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jindai; LI Ziying

    2008-01-01

    This paper is briefly involved in distributions of China's uranium metallogenic types,provinces, regions and belts. Eight target regions have been pointed out to be worthy of prospectingfor uranium resources. The regional uranium metallogeny is discussed and great uranium potentialpointed out from many aspects. Generally speaking, there are favorable conditions for uraniummineralization and good perspective to explore for uranium resources.

  19. Preparation of Uranium Powder having Reactive Shape using Uranium Hydridation

    International Nuclear Information System (INIS)

    The accident tolerance of the LWR fuel has become a primary matter of concern. So, it is indispensable to develop the innovative nuclear fuel material concepts and technologies which can overcome degradation of fuel safety and integrity. Uranium nitride fuel has been proposed as a potential fuel material for advanced nuclear reactors because nitride fuel has the advantages of both metallic and oxide fuels. That is, the high melting point, high uranium density, and high thermal conductivity are the representative merits of nitride fuel. Nitride fuel is also considered as a fuel material for the accident tolerant fuel of current LWRs to compensate for the decrease in fissile fuel material caused by adopting a thickened cladding such as SiC composites. However, nitride fuel has a critical disadvantage of a serious reaction with water at a typical LWR condition. Bulk uranium nitride is known to be dissolved in water at a temperature above 230 .deg. C. Uranium nitride powder is more unstable and reacts with water at about 150 .deg. C. Therefore, the water-proof nitride fuel must be developed to apply to current LWRs. Several strategies to prevent or reduce the reaction of nitride fuel with water have been suggested. KAERI is developing uranium nitride-oxide composite fuel pellet that is expected to have higher fuel performance and lower water reactivity. In the development of the fabrication technologies of uranium based composite fuel pellet, uranium nitride powder should be prepared, first. We have considered a simple reaction method to fabricate uranium nitride powders directly from metal uranium powders. Also, to create reactive uranium powder with nitrogen, it is applied that the uranium powder is pretreated in the hydrogen atmosphere. In this study, to investigate the behavior of the uranium powder hydriding process, thermal analysis tests were performed

  20. Integrally cored ceramic investment casting mold fabricated by ceramic stereolithography

    Science.gov (United States)

    Bae, Chang-Jun

    Superalloy airfoils are produced by investment casting (IC), which uses ceramic cores and wax patterns with ceramic shell molds. Hollow cored superalloy airfoils in a gas turbine engine are an example of complex IC parts. The complex internal hollow cavities of the airfoil are designed to conduct cooling air through one or more passageways. These complex internal passageways have been fabricated by a lost wax process requiring several processing steps; core preparation, injection molding for wax pattern, and dipping process for ceramic shell molds. Several steps generate problems such as high cost and decreased accuracy of the ceramic mold. For example, costly tooling and production delay are required to produce mold dies for complex cores and wax patterns used in injection molding, resulting in a big obstacle for prototypes and smaller production runs. Rather than using separate cores, patterns, and shell molds, it would be advantageous to directly produce a mold that has the casting cavity and the ceramic core by one process. Ceramic stereolithography (CerSLA) can be used to directly fabricate the integrally cored ceramic casting mold (ICCM). CerSLA builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This dissertation addresses the integrally cored casting ceramic mold (ICCM), the ceramic core with a ceramic mold shell in a single patternless construction, fabricated by ceramic stereolithography (CerSLA). CerSLA is considered as an alternative method to replace lost wax processes, for small production runs or designs too complex for conventional cores and patterns. The main topic is the development of methods to successfully fabricate an ICCM by CerSLA from refractory silica, as well as related issues. The related issues are the segregation of coarse fused silica powders in a layer, the degree of segregation parameter to

  1. Grain boundaries in ceramics and ceramic-metal interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, D.R.; Wolf, D.

    1986-01-01

    Three interfaces exist: the crystal-crystal grain boundary in very pure single-phase ceramics, the crystal-glass-crystal grain boundary in most single-phase and polyphase ceramics, and the ceramic-metal interface. It is needed to correlate their structure and adhesion/failure. Methods for studying the bonding, interfacial structure, and fracture and adhesion are discussed, and recommendations are given. 42 refs. (DLC)

  2. Ceramic Stereolithography: Additive Manufacturing for Ceramics by Photopolymerization

    Science.gov (United States)

    Halloran, John W.

    2016-07-01

    Ceramic stereolithography and related additive manufacturing methods involving photopolymerization of ceramic powder suspensions are reviewed in terms of the capabilities of current devices. The practical fundamentals of the cure depth, cure width, and cure profile are related to the optical properties of the monomer, ceramic, and photo-active components. Postpolymerization steps, including harvesting and cleaning the objects, binder burnout, and sintering, are discussed and compared with conventional methods. The prospects for practical manufacturing are discussed.

  3. Fabrication and testing of ceramic UO2 fuel - I-III. Part I

    International Nuclear Information System (INIS)

    The task described consists of the following: fabrication of UO2 with different granulation from uranyl nitrate by ammonia diuranate; determination of size and shape distributions of metal and ceramic powders; fabrication of sintered pressed samples UO2; investigating the properties of sintered uranium dioxide dependent on the fabrication process; producing a vibrator for compacting UO2 powder. This volume includes reports on the first two tasks

  4. Plasma hydrogen reduction of uranium from depleted uranium hexafluoride

    International Nuclear Information System (INIS)

    Process scheme of plasma hydrogen reduction of waste by 235U uranium hexafluoride, preparation of metal uranium and anhydrous hydrogen fluoride is proposed. Results of the experimental investigations into the basic stages of this process scheme: production of the U - F - H-plasma, production and separation of uranium melt and anhydrous of hydrogen fluoride are treated. Level of plasma and high frequency technique for the realization of the plasma hydrogen process of conversion of waste UF6 for metal uranium and anhydrous HF was analyzed

  5. Geology and evaluation of the uranium mineral occurrence at Igdlorssuit, South Greenland

    International Nuclear Information System (INIS)

    Geological and radiometric mapping, and petrological and mineralogical investigations were made of a uranium mineral occurrence at Igdlorssuit, South Greenland during 1984 and 1985. The results have been evaluated in terms of the uranium potential and genesis the showing. The work was part of the South Greenland Exploration Programme (Sydex) carried out by the Geological Survey of Greenland (GGU) in cooperation with Risoe National Laboratory (Risoe). It was financed by the Danish Ministry of Energy. Igdlorssuit is located at the northerly limit of the fjord system about 60 km north of Kap Farvel (60 deg. 23 min.; 46 deg. 06 min.). The main uranium mineral showing is on a small alp on the eastern side, 500 m vertically above the fjord. Detailed plane table mapping (1:1000), and radiometric measurements with a lead collimated scintillometer calibrated for uranium delineated this occurrence: Regional mapping (1:10 000), however, showed that it was only one of many similar uranium occurrences in the area albeit the largest and richest. Over 35 uranium mineral occurences have been found scattered over the hillside. Textural and paragenetic relationships, and isotopic data show that the uranium was present in the supracrustal units before the folding, metamorphism and intrusion of the granite. The largest, highest grade uranium mineralised zone is about 50m long and up to 5m wide with an average grade of 0.31% with highs up to 7%. The results of the mapping and sampling has established that this type of mineral occurence can reach economic grades, and its surface expression suggests a size which could approach economic proportions. 3 maps, 30 refs. (EG)

  6. Riddle of depleted uranium

    International Nuclear Information System (INIS)

    Depleted Uranium (DU) is the waste product of uranium enrichment from the manufacturing of fuel rods for nuclear reactors in nuclear power plants and nuclear power ships. DU may also results from the reprocessing of spent nuclear reactor fuel. Potentially DU has both chemical and radiological toxicity with two important targets organs being the kidney and the lungs. DU is made into a metal and, due to its availability, low price, high specific weight, density and melting point as well as its pyrophoricity; it has a wide range of civilian and military applications. Due to the use of DU over the recent years, there appeared in some press on health hazards that are alleged to be due to DU. In these paper properties, applications, potential environmental and health effects of DU are briefly reviewed

  7. Depleted uranium: Metabolic disruptor?

    International Nuclear Information System (INIS)

    The presence of uranium in the environment can lead to long-term contamination of the food chain and of water intended for human consumption and thus raises many questions about the scientific and societal consequences of this exposure on population health. Although the biological effects of chronic low-level exposure are poorly understood, results of various recent studies show that contamination by depleted uranium (DU) induces subtle but significant biological effects at the molecular level in organs including the brain, liver, kidneys and testicles. For the first time, it has been demonstrated that DU induces effects on several metabolic pathways, including those metabolizing vitamin D, cholesterol, steroid hormones, acetylcholine and xenobiotics. This evidence strongly suggests that DU might well interfere with many metabolic pathways. It might thus contribute, together with other man-made substances in the environment, to increased health risks in some regions. (authors)

  8. Recovery of uranium from lignites

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, F.J.

    1980-01-01

    Uranium in raw lignite is associated with the organic matter and is readily soluble in acid (and carbonate) solutions. However, beneficiation techniques were not successful for concentrating the uranium or removing part of the reagent-consuming materials. Once the lignite was heated, the uranium became much less soluble in both acid and carbonate solutions, and complete removal of carbon was required to convert it back to a soluble form. Proper burning improves acid-leaching efficiency; that is, it reduces the reagent consumption and concentrates the uranium, thereby reducing plant size for comparable uranium throughput, and it eliminates organic fouling of leach liquors. Restrictions are necessary during burning to prevent the uranium from becoming refractory. The most encouraging results were obtained by flash-burning lignite at 1200 to 1300/sup 0/C and utilizing the released SO/sub 2/ to supplement the acid requirement. The major acid consumers were aluminum and iron.

  9. Radiochemistry of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Gindler, J.E.

    1962-03-01

    This volume which deals with the radiochemistry of uranium is one of a series of monographs on radiochemistry of the elements. There is included a review of the nuclear and chemical features of particular interest to the radiochemist, a discussion of problems of dissolution of a sample and counting technique, and finally, a collection of radiochemical procedures for the element as found in the literature.

  10. Uranium in Mongolia

    International Nuclear Information System (INIS)

    Full text: Mongolian electricity is produced from fossil fuels (about 98%, mainly coal). Rapid growth in demand has given rise to power shortages, and the reliance on fossil fuels has led to much air pollution. Mongolia does not have nuclear reactor and thus is not a beneficiary of nuclear technology. In April 2008 Russia and Mongolia signed a high-level agreement to cooperate in identifying and developing Mongolia's uranium resources. Russia is also examining the feasibility of building nuclear power plants in Mongolia In our government need to create the environment for investment in nuclear power, including professional regulatory regime, policies on nuclear waste management and decommissioning, and involvement with international non-proliferation and insurance arrangements. Some 46 million kilowatt-hours of electricity are produced from one tones of natural uranium. The production of this amount of electrical power from fossil fuels would require the burning of over 20 000 tonnes of black coal or 8.5 million cubic meters of gas. Mongolia has a long history of uranium exploration commencing with joint Russian and Mongolian endeavors to 1957. Today the Canada-based Khan Resources owns a 69% share in the Dornod project through its subsidiary Central Asian Uranium Co. Ltd and Russia's Priargunsky Mining and Chemical Enterprise owns a further share. In 2007 Khan published NI 43-101 compliant indicated resource figure of 25 000 tU for the project, including probable reserves of 7 000 tU. A bankable feasibility study is now being undertaken, with capital cost estimate being US$283 million and first production in 2011. Khan has applied for a mining licence from the Mineral Resources and Petroleum Authority of Mongolia (MRPAM). (author)

  11. Uranium in western Europe

    International Nuclear Information System (INIS)

    Uranium has been in use in Europe since the Middle Ages, and working of uraniferous minerals on an industrial scale for the production of radium began in Portugal and Czechoslovakai in 1904. Mining began soon after World War II for the production of fissile material. Western Europe's uranium resources represent about a tenth of the world's resources, of 486 950 tonnes recoverable at $130 per kg or less. Production in 1978 was 2 513 tonnes of uranium. The principal producing countries were the Federal Republic of Germany, Spain, France, and Portugal. Uraniferous vein deposits occur in the Moldanubian granites, the Iberian Meseta, the Armorican massif, the Massif Central, and the Black Forest. Deposits associated with sedimentary rocks occur in the Cambrian shales of Ranstad, the Permian lutites and silts of Lodeve, and in grits and sandstones elsewhere. Volcanic deposits are present in Alpine areas. The current rate of exploration must be maintained if the energy needs of Europe predicted for the year 2000 are to be met. (L.L.)

  12. Uranium in situ leaching

    International Nuclear Information System (INIS)

    Despite the depressed situation that has affected the uranium industry during the past years, the second Technical Committee Meeting on Uranium In Situ Leaching, organized by the International Atomic Energy Agency and held in Vienna from 5 to 8 October 1992, has attracted a relatively large number of participants. A notable development since the first meeting was that the majority of the contributions came from the actual operators of in situ leaching uranium production. At the present meeting, presentations on operations in the USA were balanced by those of the eastern European and Asian countries. Contributions from Bulgaria, China, Czechoslovakia, Germany (from the operation in the former German Democratic Republic), the Russian Federation and Uzbekistan represent new information not commonly available. In situ leach mining is defined in one of the paper presented as a ''mining method where the ore mineral is preferentially leached from the host rock in place, or in situ, by the use of leach solutions, and the mineral value is recovered. Refs, figs and tabs

  13. Ceramic Composite Thin Films

    Science.gov (United States)

    Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor); Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor)

    2013-01-01

    A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

  14. Main geological settings of uranium mineralization in the Baltic shield

    International Nuclear Information System (INIS)

    Uranium and uranium-associated deposits of the Baltic Shield occur in a variety of structurematter settings. Most prospective of the latter are (1) Zones of structure-stratigraphic unconformity (SSU): those of Prevendian SSU in the basement of the Russian platform, those of Preriphean SSU in the basement of Pasha-Ladoga, Tersky bereg and other Riphean troughs, and those of Preyatulian SSU in the basement of Early Proterozoic superimposed depressions. (2) Zones of fold-fracture dislocations (FFD) in the Early Proterozoic troughs characterized with widespread black shale. Uranium mineralization occurrences within the old uranium-bearing SSU zones are of different grade: high-grade ore in the Preriphean SSU zone, low-grade ore but of significant content in the Prevendian SSU zone, ore of an uncertain,by now, grade in the Preyatulian SSU zone. The prospect for the first zone has been determined so far by the discovery of the Karku deposit in the Pasha-Ladoga trough, for the second - by the discovery of the Ratnitsa, Ryabinovka and other deposits, and, finally, for the third one - by the presence of numerous poorly studied ore mineralization occurrences - Palozerj-1,2, Maimjarvi-1, etc. Regionally, the distribution of uranium mineralization restricted to the SSU zones is controlled by a variety of factors: linear grabens complicated by fold-fracture zones on the boundaries of major earth crust blocks (Preriphean SSU), by the juncture of the Russian plate rock complex with the Baltic Shield structures, by the localization within the regional fracture-block zone (Prevendian SSU, by occurrence on the slope of the Early Protewrozoic superimposed depression complicated by deep fault zones (Preyatulian SSU). All SSUs result from the flat dip of sedimentary rocks (Vendian, Riphean, Yatulian ones) onto the rocks of the Archean-Proterozoic or Archean basement. The latter rocks are heterogeneous in composition, contain carbonaceous and carbon-bearing varieties, display intensive

  15. COGEMA's UMF [Uranium Management Facility

    International Nuclear Information System (INIS)

    The French government-owned corporation, COGEMA, is responsible for the nuclear fuel cycle. This paper describes the activities at COGEMA's Pierrelatte facility, especially its Uranium Management Facility. UF6 handling and storage is described for natural, enriched, depleted, and reprocessed uranium. UF6 quality control specifications, sampling, and analysis (halocarbon and volatile fluorides, isotopic analysis, uranium assay, and impurities) are described. In addition, the paper discusses the filling and cleaning of containers and security at UMF

  16. Uranium Critical Point Location Problem

    CERN Document Server

    Iosilevskiy, Igor

    2013-01-01

    Significant uncertainty of our present knowledge for uranium critical point parameters is under consideration. Present paper is devoted to comparative analysis of possible resolutions for the problem of uranium critical point location, as well as to discussion of plausible scheme of decisive experiment, which could resolve existing uncertainty. New calculations of gas-liquid coexistence in uranium by modern thermodynamic code are included in the analysis.

  17. Uranium-Based Cermet Alloys

    International Nuclear Information System (INIS)

    The paper describes certain features of dispersion-hardened uranium-based cermets. As possible hardening materials, consideration was given to UO2, UC, Al2O3, MgO and UBe13. Data were obtained on the behaviour of uranium alloys containing the above-mentioned admixtures during creep tests, short-term strength tests and cyclic thermal treatment. The corrosion resistance o f UBe13-based uranium alloys was also studied. )author)

  18. Vascular grading of angiogenesis

    DEFF Research Database (Denmark)

    Hansen, S; Grabau, D A; Sørensen, Flemming Brandt;

    2000-01-01

    was moderately reproduced (kappa = 0.59). Vascular grade was significantly associated with axillary node involvement, tumour size, malignancy grade, oestrogen receptor status and histological type. In univariate analyses vascular grade significantly predicted recurrence free survival and overall survival for all...... patients (P analysis showed that vascular grading contributed with independent prognostic value in all patients (P

  19. Tailored Ceramics for Laser Applications

    Energy Technology Data Exchange (ETDEWEB)

    Hollingsworth, Joel [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2007-12-10

    Transparent ceramics match or exceed the performance of single-crystal materials in laser applications, with a more-robust fabrication process. Controlling the distribution of optical dopants in transparent ceramics would allow qualitative improvements in amplifier slab design by allowing gain and loss to be varied within the material. My work aims to achieve a controlled pattern or gradient of dopant prior to sintering, in order to produce tailored ceramics.

  20. Ceramic cooling tower packings

    Energy Technology Data Exchange (ETDEWEB)

    Honekamp, H.; Katzmann, A.

    1986-05-01

    No material for cooling tower packings demonstrates all the characteristics desired by the designer. The choice of a specific material must therefore always be oriented towards the limiting conditions of a specific project. Resistance to frost, combustibility and resistance to ageing may, for example, be determining requirements. Ceramic stones will find further possibilities of application in the near future due to their almost unlimited durability.

  1. Rheology of Superplastic Ceramics

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Constitutive equation of rheglogy describing a phenomenological level of superplastic deformation as functional correlation between tensor components of stress and strain rate has been analyzed for the case of superplastic ceramic flow. Rheological properties of material are taken into account by means of scalar rheological coefficients of shear and volume viscosity, which are functions of temperature, effective stress (or strain rate) and density of material.

  2. Laser Micromachining of Ceramics

    OpenAIRE

    Sciti, Diletta; Bellosi, Alida

    2011-01-01

    Laser surface processing of ceramics is an area of considerable technological importance for several structural, tribological, optical and electronic applications. The laser beam behaves as a heat source that induces a temperature rise on the surface and within the bulk of the material. Depending on laser parameters and material characteristics, lasers can be used for fabricating microholes at designated locations, for cutting, scribing, for surface modifications In this work different types ...

  3. Recent developments in uranium exploration, production and environmental issues. Proceedings of a technical meeting

    International Nuclear Information System (INIS)

    production companies have initiated uranium exploration to increase resources associated with current operations and to confirm the potential of other known deposits and regional exploration trends. Niger exports all of its uranium so market price and project economics are important factors to its uranium industry. By contrast, all of India's uranium production is dedicated to its domestic nuclear power programme. Though uranium production is less sensitive to production economics, India is nevertheless emphasizing exploration in geologic environments that have the potential to host large, high-grade deposits with the potential for lower production costs. To ensure self-sufficiency in the near term, India is also developing new production capability in a variety of geologic environments with well-established resources, but with lower grades and capacity potential. The recent market price increase has made projected production costs for two of Argentina's uranium projects more competitive in the marketplace. Before re-starting existing projects or developing new projects, however, Argentina's production company, CNEA, must acquire a number of mining permits and licenses. To ensure that its projects gain public and regulatory approval, CNEA has implemented programmes that emphasize technology that will ensure that its proposed operations meet regulatory requirements. It has also initiated a public relations programme to demonstrate the environmental compatibility of its projects to affected communities. Uranium mining and processing and site rehabilitation in the Czech Republic are closely monitored by the State Office for Nuclear Safety (SUJB). The oversight responsibilities of SUJB and the body of law that ensures its authority are presented in paper that may be useful to countries with emerging nuclear industries. Approximately 80% of China's uranium resource base is hosted in hard rock geologic environments, mainly in vein deposits in granites and volcanic complexes. These

  4. Preparation and characteristics of porous ceramics

    Institute of Scientific and Technical Information of China (English)

    Dongmei SHAO; Peiping ZHANG; Liyan MA; Juanjuan LIU

    2007-01-01

    Pyrophyllite is always used for making porous ceramics. In order to design the preparation technics of porous ceramics with pyrophyllite reasonably we must know the classifications, characteristics, properties and applications of porous ceramics. The classification and characteristics of porous ceramics are reviewed in this article; and several common preparations with their advantages and disadvantages are also introduced. The authors discussed the problems existing in researching and developing process for porous ceramics, and forecasted the development prospect of porous ceramics.

  5. The Toxicity of Depleted Uranium

    Directory of Open Access Journals (Sweden)

    Wayne Briner

    2010-01-01

    Full Text Available Depleted uranium (DU is an emerging environmental pollutant that is introduced into the environment primarily by military activity. While depleted uranium is less radioactive than natural uranium, it still retains all the chemical toxicity associated with the original element. In large doses the kidney is the target organ for the acute chemical toxicity of this metal, producing potentially lethal tubular necrosis. In contrast, chronic low dose exposure to depleted uranium may not produce a clear and defined set of symptoms. Chronic low-dose, or subacute, exposure to depleted uranium alters the appearance of milestones in developing organisms. Adult animals that were exposed to depleted uranium during development display persistent alterations in behavior, even after cessation of depleted uranium exposure. Adult animals exposed to depleted uranium demonstrate altered behaviors and a variety of alterations to brain chemistry. Despite its reduced level of radioactivity evidence continues to accumulate that depleted uranium, if ingested, may pose a radiologic hazard. The current state of knowledge concerning DU is discussed.

  6. Ceramic stationary gas turbine

    Energy Technology Data Exchange (ETDEWEB)

    Roode, M. van [Solar Turbines Inc., San Diego, CA (United States)

    1995-10-01

    The performance of current industrial gas turbines is limited by the temperature and strength capabilities of the metallic structural materials in the engine hot section. Because of their superior high-temperature strength and durability, ceramics can be used as structural materials for hot section components (blades, nozzles, combustor liners) in innovative designs at increased turbine firing temperatures. The benefits include the ability to increase the turbine inlet temperature (TIT) to about 1200{degrees}C ({approx}2200{degrees}F) or more with uncooled ceramics. It has been projected that fully optimized stationary gas turbines would have a {approx}20 percent gain in thermal efficiency and {approx}40 percent gain in output power in simple cycle compared to all metal-engines with air-cooled components. Annual fuel savings in cogeneration in the U.S. would be on the order of 0.2 Quad by 2010. Emissions reductions to under 10 ppmv NO{sub x} are also forecast. This paper describes the progress on a three-phase, 6-year program sponsored by the U.S. Department of Energy, Office of Industrial Technologies, to achieve significant performance improvements and emissions reductions in stationary gas turbines by replacing metallic hot section components with ceramic parts. Progress is being reported for the period September 1, 1994, through September 30, 1995.

  7. Uranium exploration in Ethiopia

    International Nuclear Information System (INIS)

    Full text: Radioactive exploration dates back to 1955 and since then little progress has been made. Few pits and trenches in some places show radioactive anomalies.The Wadera radioactive anomaly occurs within the lower part of Wadera series, Southern Ethiopia. As observed from a trench the anomalous bed has a thickness of 0.9-1.2 m and is made of reddish-grey thin bedded sandstones.The presence of Xenotime in arkosic sandstone points to the sedimentary origin of mineralization. It was noticed that the sandstone in the lower part of Wadera series has at places a radioactivity 2-3 times higher than adjacent gneisses. The presence of a placer of such a type in the Wadera series is probably a clue for the existence of larger deposits in the area. In 2007 geological, geochemical and geophysical surveys were conducted to identify and delineate Uranium mineralization in three localities(Kuro, Kalido and Gueti) of Werri area, southern Ethiopia. Kaolinization, silicification, epidotization and chloritization are the main types of alteration associated with different units in the area. Uranium-bearing grains which are hosted in pegmatite veins and associated with magnetite/or ilmenite were observed in the three localities. Geochemical exploration accompanied by geological mapping and radiometric survey was done by employing heavy mineral concentrate, soil, chip and trench channel sampling. Radiometric readings of total count, U,Th and K were taken using GAD-6.Soil and trench geochemical samples of the localities analyzed by ICP-MS have shown 0.1 to 3.8 ppm and 3.9 to 147 ppm Uranium and 3.5 to 104.7 ppm and 3.9 to 147ppm Thorium respectively. Radiometric reading is higher in pegmatite veins that host Uranium-bearing minerals and some course grained pegmatoidal granite varieties. The areas recognized for Uranium associations need further investigations using state-of-the-art to discover economic deposits for development and utilization of the resource. (author)

  8. METHOD FOR RECOVERING URANIUM FROM OILS

    Science.gov (United States)

    Gooch, L.H.

    1959-07-14

    A method is presented for recovering uranium from hydrocarbon oils, wherein the uranium is principally present as UF/sub 4/. According to the invention, substantially complete removal of the uranium from the hydrocarbon oil may be effected by intimately mixing one part of acetone to about 2 to 12 parts of the hydrocarbon oil containing uranium and separating the resulting cake of uranium from the resulting mixture. The uranium in the cake may be readily recovered by burning to the oxide.

  9. Topical and working papers on uranium resources and availability

    International Nuclear Information System (INIS)

    Basic topics relative to world-wide resources and availability of uranium resources; potential for recovery of uranium from mill tailings in Canada; uranium from seawater; depleted uranium as an energy source; world uranium requirements in perspective

  10. 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 .

  11. Synthesis of the U.S. specified ceramics using MOX fuel production expertise

    Science.gov (United States)

    Astafiev, V. A.; Glushenkov, A. E.; Sideinikov, M.; Borisov, G. B.; Mansourov, O. A.; Jardine, L. J.

    2000-07-01

    At present, under the auspices of the USA/Russia agreements, joint work is under way to dispose of excess plutonium being withdrawn from nuclear defense programs. A major approach is to produce mixed plutonium-uranium fuel (MOX fuel) for its further burnup in different nuclear reactors. Plutonium-containing materials, which upon their composition or from an economic standpoint cannot be used for MOX fuel production, are to be immobilized into solid ceramic and glass-type matrices with their safe storage and eventual geologic disposal. For an immobilization form in the U.S., it is proposed to use ceramics based on pyrochlore developed at LLNL that is capable of incorporating up to 10 wt.% PuO2 and 23 wt.% UO2. At VNIINM, work was done to assess the possibility of using equipment and expertise of MOX-fuel production to fabricate the ceramics. A few of the ceramic samples were synthesized, and basic physicochemical properties, including the homogeneity of the plutonium and uranium distributions in the matrix, density, and pellet porosity, were also measured.

  12. Hydrogeochemistry and uranium fixation in the Cigar Lake uranium deposit, northern Saskatchewan

    International Nuclear Information System (INIS)

    The 1.3 billion year old Cigar Lake uranium deposit, discovered by COGEMA in 1981, is a very rich and large mineralization of uraninite-pitchblende and coffinite in the Athabasca Sandstone in northern Saskatchewan. The mineralization occurs at the -450 m deep unconformity contact of the sandstone with the underlying high-grade rocks of the basement. The sandstone, particularly its basal unit, is the regional aquifer and, due to permeability caused by extensive fracturing, groundwater is found in all parts of the deposit. The composition of this groundwater has been studied in detail over the past 3 years. The compositions of the groundwaters from different parts of the deposit reveal a reduced, redox-buffered, steady-state system of water interaction with the ore and host rock. All groundwaters, including those in contact with the mineralization, are dilute, neutral pH waters containing low concentrations of dissolved uranium (∼10-7.9 to 10-9 mol/L U). Concentrations of dissolved radium-226 and radon-222 are also low except in groundwaters sampled within the ore zone. The redox chemistry is controlled by a number of different processes, including inorganic and organic reactions, bacterial activity and radiolysis of water in the ore zone. The iron-redox couple is the main process controlling the redox conditions in the present dynamic system. The formation of iron colloids in the ore zone and the retention of these colloids in the bordering clay zone restrict the migration of naturally occurring radionuclides, such as uranium, thorium and radium, from the ore. Information from the redox, colloid and isotope chemistries is used to discuss the history of uranium fixation in this deposit. (author)

  13. Bioleaching of Rare Earth Elements and Uranium From Sinai Soil, Egypt Using Actinomycetes

    OpenAIRE

    Maha Amin Hewedy, Abeer Ahmed Rushdy, and Noha Mohammed Kamal

    2013-01-01

    The use of microorganisms in the recovery of Rare Earth Elements (REEs) and Uranium (U) from low grade ores provides an appropriate eco-friendly alternative to chemical methods used in extraction and/or removal of metals from soils, with a higher efficiency, less destruction to the environment, and lower cost from a commercial view especially given that high-grade mineral resources that can be used in the chemical extraction of metals are being depleted. The feasibility of using actinomycetes...

  14. Immobilization of preconditioned spent fuel from nuclear research reactors in a ceramic matrix

    International Nuclear Information System (INIS)

    The fuel elements from nuclear research reactors consist in a laminated sandwich of aluminum with a core of some uranium compound. To process this material its necessary to previously eliminate the aluminum covering the fuel, before the conditioning of the rest of the fuel in a stable matrix, in order to obtain an acceptable waste form for a subsequent disposition in a geological repository. Normally, mechanical and chemical methods are proposed for that purpose. One of the most developed techniques for immobilization of the radioactive elements above mentioned, is the vitrification. In this work we propose a method named CERUS (in Spanish Ceramizacion de Elementos Radiactivos con Uranio Sinterizado - Ceramization of radioactive elements with sintered uranium). This is a sinterization of the pre-treated fuel elements mixed with natural uranium oxide. The properties of the blocks obtained are adequate for final disposal in a deep geological reservoir. (author)

  15. 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.

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

    Science.gov (United States)

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

    2016-05-01

    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.

  17. Uranium Stewardship - The unifying foundation

    International Nuclear Information System (INIS)

    Full text: Uranium Stewardship is a WNA programme of action seeking to define, and achieve worldwide industry adherence to, principles and practices designed to ensure that uranium and its by-products are managed in ways that are safe, environmentally responsible, and economically and socially acceptable. Through this programme WNA will engage all industry sectors involved with the uranium life cycle, as well as relevant stakeholders, with the objective of first encouraging best practice, then sustaining an ongoing industry effort to continually improve it. In pursuing this objective WNA has identified key Principles of Uranium Stewardship and will aim to obtain, from all relevant enterprises, formal commitment to a Code of Practice that translates these principles into worldwide industry performance. The WNA sets forth these Principles of Uranium Stewardship as the basis for a Code of Practice, to which relevant enterprises are invited to commit and adhere: 1. Support the safe and peaceful use of nuclear technology. 2. Act responsibly in all areas we manage and control. 3. Operate ethically with sound corporate governance. 4. Uphold and respect fundamental human rights. 5. Contribute to the social and economic development of regions where we operate. 6. Provide for responsible sourcing, use and disposition of uranium and its by-products. 7. Support best practice and responsible behaviour throughout the nuclear fuel cycle. 8. Improve continually in all areas of our performance. 9. Communicate regularly on progress. 10. Review and update. The Australian Uranium Association's Uranium Stewardship Principles reflect and are consistent with the global principles being developed under the auspices of the World Nuclear Association. The Association's Principles are additional to the broader Australian minerals industry's commitment to sustainable development as outlined in the Minerals Council of Australia's Enduring Value; and to the Australian Uranium Association

  18. Standard specification for uranium hexafluoride enriched to less than 5 % 235U

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This specification covers nuclear grade uranium hexafluoride (UF6) that either has been processed through an enrichment plant, or has been produced by the blending of Highly Enriched Uranium with other uranium to obtain uranium of any 235U concentration below 5 % and that is intended for fuel fabrication. The objectives of this specification are twofold: (1) To define the impurity and uranium isotope limits for Enriched Commercial Grade UF6 so that, with respect to fuel design and manufacture, it is essentially equivalent to enriched uranium made from natural UF6; and (2) To define limits for Enriched Reprocessed UF6 to be expected if Reprocessed UF6 is to be enriched without dilution with Commercial Natural UF6. For such UF6, special provisions, not defined herein, may be needed to ensure fuel performance and to protect the work force, process equipment, and the environment. 1.2 This specification is intended to provide the nuclear industry with a standard for enriched UF6 that is to be used in the pro...

  19. First principle active neutron coincidence counting measurements of uranium oxide

    Science.gov (United States)

    Goddard, Braden; Charlton, William; Peerani, Paolo

    2014-03-01

    Uranium is present in most nuclear fuel cycle facilities ranging from uranium mines, enrichment plants, fuel fabrication facilities, nuclear reactors, and reprocessing plants. The isotopic, chemical, and geometric composition of uranium can vary significantly between these facilities, depending on the application and type of facility. Examples of this variation are: enrichments varying from depleted (~0.2 wt% 235U) to high enriched (>20 wt% 235U); compositions consisting of U3O8, UO2, UF6, metallic, and ceramic forms; geometries ranging from plates, cans, and rods; and masses which can range from a 500 kg fuel assembly down to a few grams fuel pellet. Since 235U is a fissile material, it is routinely safeguarded in these facilities. Current techniques for quantifying the 235U mass in a sample include neutron coincidence counting. One of the main disadvantages of this technique is that it requires a known standard of representative geometry and composition for calibration, which opens up a pathway for potential erroneous declarations by the State and reduces the effectiveness of safeguards. In order to address this weakness, the authors have developed a neutron coincidence counting technique which uses the first principle point-model developed by Boehnel instead of the "known standard" method. This technique was primarily tested through simulations of 1000 g U3O8 samples using the Monte Carlo N-Particle eXtended (MCNPX) code. The results of these simulations showed good agreement between the simulated and exact 235U sample masses.

  20. SULPHUR DIOXIDE LEACHING OF URANIUM CONTAINING MATERIAL

    Science.gov (United States)

    Thunaes, A.; Rabbits, F.T.; Hester, K.D.; Smith, H.W.

    1958-12-01

    A process is described for extracting uranlum from uranium containing material, such as a low grade pitchblende ore, or mill taillngs, where at least part of the uraniunn is in the +4 oxidation state. After comminuting and magnetically removing any entrained lron particles the general material is made up as an aqueous slurry containing added ferric and manganese salts and treated with sulfur dioxide and aeration to an extent sufficient to form a proportion of oxysulfur acids to give a pH of about 1 to 2 but insufficient to cause excessive removal of the sulfur dioxide gas. After separating from the solids, the leach solution is adjusted to a pH of about 1.25, then treated with metallic iron in the presence of a precipitant such as a soluble phosphate, arsonate, or fluoride.

  1. Solubility measurement of uranium in uranium-contaminated soils

    International Nuclear Information System (INIS)

    A short-term equilibration study involving two uranium-contaminated soils at the Fernald site was conducted as part of the In Situ Remediation Integrated Program. The goal of this study is to predict the behavior of uranium during on-site remediation of these soils. Geochemical modeling was performed on the aqueous species dissolved from these soils following the equilibration study to predict the on-site uranium leaching and transport processes. The soluble levels of total uranium, calcium, magnesium, and carbonate increased continually for the first four weeks. After the first four weeks, these components either reached a steady-state equilibrium or continued linearity throughout the study. Aluminum, potassium, and iron, reached a steady-state concentration within three days. Silica levels approximated the predicted solubility of quartz throughout the study. A much higher level of dissolved uranium was observed in the soil contaminated from spillage of uranium-laden solvents and process effluents than in the soil contaminated from settling of airborne uranium particles ejected from the nearby incinerator. The high levels observed for soluble calcium, magnesium, and bicarbonate are probably the result of magnesium and/or calcium carbonate minerals dissolving in these soils. Geochemical modeling confirms that the uranyl-carbonate complexes are the most stable and dominant in these solutions. The use of carbonate minerals on these soils for erosion control and road construction activities contributes to the leaching of uranium from contaminated soil particles. Dissolved carbonates promote uranium solubility, forming highly mobile anionic species. Mobile uranium species are contaminating the groundwater underlying these soils. The development of a site-specific remediation technology is urgently needed for the FEMP site

  2. Profile of World Uranium Enrichment Programs - 2007

    Energy Technology Data Exchange (ETDEWEB)

    Laughter, Mark D [ORNL

    2007-11-01

    It is generally agreed that the most difficult step in building a nuclear weapon is acquiring weapons grade fissile material, either plutonium or highly enriched uranium (HEU). Plutonium is produced in a nuclear reactor, while HEU is produced using a uranium enrichment process. Enrichment is also an important step in the civil nuclear fuel cycle, in producing low enriched uranium (LEU) for use in fuel for nuclear reactors. However, the same equipment used to produce LEU for nuclear fuel can also be used to produce HEU for weapons. Safeguards at an enrichment plant are the array of assurances and verification techniques that ensure uranium is only enriched to LEU, no undeclared LEU is produced, and no uranium is enriched to HEU or secretly diverted. There are several techniques for enriching uranium. The two most prevalent are gaseous diffusion, which uses older technology and requires a lot of energy, and gas centrifuge separation, which uses more advanced technology and is more energy efficient. Gaseous diffusion plants (GDPs) provide about 40% of current world enrichment capacity, but are being phased out as newer gas centrifuge enrichment plants (GCEPs) are constructed. Estimates of current and future enrichment capacity are always approximate, due to the constant upgrades, expansions, and shutdowns occurring at enrichment plants, largely determined by economic interests. Currently, the world enrichment capacity is approximately 53 million kg-separative work units (SWU) per year, with 22 million in gaseous diffusion and 31 million in gas centrifuge plants. Another 23 million SWU/year of capacity are under construction or planned for the near future, almost entirely using gas centrifuge separation. Other less-efficient techniques have also been used in the past, including electromagnetic and aerodynamic separations, but these are considered obsolete, at least from a commercial perspective. Laser isotope separation shows promise as a possible enrichment technique

  3. 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

  4. Chapter 3. Classical method of uranium leaching from ores and reasons for incomplete recovery at dumps of State Enterprise 'VOSTOKREDMET'. 3.2. Uranium extraction from the ore and classification of its losses

    International Nuclear Information System (INIS)

    Present article is devoted to uranium extraction from the ore and classification of its losses. It was found that uranium commodity balance that has decisive importance during the actual assessment of an enterprise's activity is formed on the basis of chemical sampling and weight accounting for the head grade delivered to the plant, together with the ore and produced finished product. Process balance reflects the actual process nature of uranium extraction from ore into the finished product, the basis of which is the chemical analysis of ore and hydrometallurgical redistribution products on basic operations of the manufacturing process. Technological balance enables, through an analytical approach, to identify uranium extraction by technological redistribution and, in whole, the percentage and weight outcome, uranium concentration degree and extent of process loss. Process extraction does not take into account mechanical losses and therefore, as a rule, exceeds the commodity to an extent of those losses. It was defined that sorption redistribution losses of plant's process flow diagram are uranium losses with hydrates, with slurry solution and with granule resin. Sum of these losses in ratio to uranium amount delivered for sorption defines the process extraction value of sorption redistribution. Total uranium technological extraction to finished product is defined by uranium comparing in residues released to tailings with its content in ore with a glance of increased solid volume.

  5. Uranium project DINAMIGE-BRGM

    International Nuclear Information System (INIS)

    This Uranium review was carried out in the frame work of Uranium prospecting programme between (DINAMIGE-BRGM) from February to June 1982. It was included radimetric cutting in sedimentaries and crystallines ground (gondwanic basin of the NE).The task was developed (1.300.000 scale) in Cunapiru, Carrillada, Vichadero, Minas de Corrales, Paso Mazangano and Yaguari zones.

  6. Fossile fuel and uranium resources

    International Nuclear Information System (INIS)

    The world's resources of coal, lignite, oil, natural gas, shale oil and uranium are reviewed. These quantities depend on the prices which make new resources exploitable. Uranium resources are given exclusively for the USSR, Eastern Europe and China. Their value in terms of energy depends heavily on the reactor type used. All figures given are estimated to be conservative

  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. Recrystallization of pressed technical uranium

    International Nuclear Information System (INIS)

    The objective of this task was to study changes originating from heat treatment of uranium by metallographic methods and by measuring the hardness. Correlation of previously determined textures with the present study would improve the knowledge on the recrystallization process of pressed uranium

  9. Improved Tensile Test for Ceramics

    Science.gov (United States)

    Osiecki, R. A.

    1982-01-01

    For almost-nondestructive tensile testing of ceramics, steel rod is bonded to sample of ceramic. Assembly is then pulled apart in conventional tensile-test machine. Test destroys only shallow surface layer which can be machined away making specimen ready for other uses. Method should be useful as manufacturing inspection procedure for low-strength brittle materials.

  10. Ceramics in nuclear waste management

    Energy Technology Data Exchange (ETDEWEB)

    Chikalla, T D; Mendel, J E [eds.

    1979-05-01

    Seventy-three papers are included, arranged under the following section headings: national programs for the disposal of radioactive wastes, waste from stability and characterization, glass processing, ceramic processing, ceramic and glass processing, leaching of waste materials, properties of nuclear waste forms, and immobilization of special radioactive wastes. Separate abstracts were prepared for all the papers. (DLC)

  11. Lightweight high performance ceramic material

    Science.gov (United States)

    Nunn, Stephen D [Knoxville, TN

    2008-09-02

    A sintered ceramic composition includes at least 50 wt. % boron carbide and at least 0.01 wt. % of at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy Ho, Er, Tm, Yb, and Lu, the sintered ceramic composition being characterized by a density of at least 90% of theoretical density.

  12. Uranium entrapment in wetlands: A case study at the Boston Peak fen, Colorado, U.S.A

    International Nuclear Information System (INIS)

    The Boston Peak fen, a 5-hectare, uranium-enriched wetland located northwest of Rocky Mountain National Park in northern Colorado, has been the subject of intensive study by U.S. Geological Survey scientists through surface mapping, drilling, and sampling of an extensive network of 59 auger and core holes. Uranium concentrations increased dramatically in the organic-rich gyttja (50-150 ppm) compared to the lower lakebeds (4-70 ppm). The uranium in the gyttja is stratabound, and variations in uranium content between sediment layers could be caused by differences in supply of dissolved uranium to the lake and differences in sediment redox conditions. Uranium concentrations in the gyttja drop before the transition to peat, except in lake sediment near spring or seep sources, despite the constant or increasing organic matter content of the gyttja. Dissolved uranium delivered by spring water was now locally fixed by peat adjacent to the spring pools, resulting in uranium concentrations of as much as 4,000 ppm (dry weight) whereas peat distant from spring pools may have only a few ppm of uranium. Water chemistry and uranium in peat are discussed. Studies of this wetland confirm the well-documented observation that wetlands serve as natural filters for uranium and many other potentially hazardous trace elements that may otherwise enter downstream surface waters. Inadvertent or deliberate destruction of metalbearing wetlands may diminish water quality and remove the potential for continued filtering activity. The processes affecting uranium transport, sorption, and ultimate fixation in the peat may have relevance for understanding uranium-organic associations in ore deposits in the major sandstone uranium districts of the San Juan Basin and elsewhere. Stratabound uranium in the gyttja may serve as an analogue of much older uranium- and organic-matter-rich systems such as the massive low-grade lacustrine uranium deposits of late Tertiary age in some western Arizona basins

  13. Uranium nucleophilic carbene complexes

    International Nuclear Information System (INIS)

    The only stable f-metal carbene complexes (excluding NHC) metals f present R2C2- groups having one or two phosphorus atoms in the central carbon in alpha position. The objective of this work was to develop the chemistry of carbenes for uranium (metal 5f) with the di-anion C{Ph2P(=S)}22- (SCS2-) to extend the organometallic chemistry of this element in its various oxidation states (+3-+6), and to reveal the influence of the 5f orbitals on the nature and reactivity of the double bond C=U. We first isolated the reactants M(SCHS) (M = Li and K) and demonstrated the role of the cation M+ on the evolution of the di-anion M2SCS (M = Li, K, Tl) which is transformed into LiSCHS in THF or into product of intramolecular cyclization K2[C(PhPS)2(C6H4)]. We have developed the necessary conditions mono-, bis- and tris-carbene directly from the di-anion SCS2- and UCl4, as the precursor used in uranium chemistry. The protonolysis reactions of amides compounds (U-NEt2) by the neutral ligand SCH2S were also studied. The compounds [Li(THF)]2[U(SCS)Cl3] and [U(SCS)Cl2(THF)2] were then used to prepare a variety of cyclopentadienyl and mono-cyclo-octa-tetra-enyliques uranium(IV) carbene compounds of the DFT analysis of compounds [M(SCS)Cl2(py)2] and [M(Cp)2(SCS)] (M = U, Zr) reveals the strong polarization of the M=C double bond, provides information on the nature of the σ and π interactions in this binding, and shows the important role of f orbitals. The influence of ancillary ligands on the M=C bond is revealed by examining the effects of replacing Cl- ligands and pyridine by C5H5- groups. Mulliken and NBO analyzes show that U=C bond, unlike the Zr=C bond, is not affected by the change in environment of the metal center. While the oxidation tests of carbene complexes of U(IV) were disappointing, the first carbene complex of uranium (VI), [UO2(SCS)(THF)2], was isolated with the uranyl ion UO22+. The reactions of compounds UO2X2 (X = I, OTf) with anions SCS2- and SCHS- provide the

  14. Advanced uranium enrichment processes

    International Nuclear Information System (INIS)

    Three advanced Uranium enrichment processes are dealt with in the report: AVLIS (Atomic Vapour LASER Isotope Separation), MLIS (Molecular LASER Isotope Separation) and PSP (Plasma Separation Process). The description of the physical and technical features of the processes constitutes a major part of the report. If further presents comparisons with existing industrially used enrichment technologies, gives information on actual development programmes and budgets and ends with a chapter on perspectives and conclusions. An extensive bibliography of the relevant open literature is added to the different subjects discussed. The report was drawn up by the nuclear research Centre (CEA) Saclay on behalf of the Commission of the European Communities

  15. Epidemiological study of workers at risk of internal exposure to uranium

    International Nuclear Information System (INIS)

    This work is a pilot-study among nuclear fuel cycle workers potentially exposed to alpha radiation. Internal exposure from inhalation of uranium compounds during uranium conversion and enrichment operations was estimated at the AREVA NC Pierrelatte plant. A plant specific semi-quantitative job exposure matrix (JEM) was elaborated for 2709 workers employed at this plant between 1960 and 2006. The JEM has permitted to estimate the exposure to uranium and 16 other categories of pollutants and to calculate individual cumulative exposure score. Numerous correlations were detected between uranium compounds exposure and exposure to other pollutants, such as asbestos, ceramic refractive fibers, TCE and so on. 1968-2005 mortality follow-up showed an increasing risk of mortality from pleural cancer, rectal cancer and lymphoma on the basis of national mortality rates. Analyses of association between cancer mortality and uranium exposure suggested an increase in mortality due to lung cancer among workers exposed to slowly soluble uranium compounds derived from natural and reprocessed uranium. However these results are not statistically significant and based on a small number of observed deaths. These results are concordant with previously reported results from other cohorts of workers potentially exposed to uranium. Experimental studies of biokinetic and action mechanism of slowly soluble uranium oxides bear the biological plausibility of the observed results. Influence of bias was reduced by taking into account of possible confounding including co-exposure to other carcinogenic pollutants and tobacco consumption in the study. Nevertheless, at this stage statistical power of analyses is too limited to obtain more conclusive results. This pilot study shows the interest and feasibility of an epidemiological investigation among workers at risk of internal exposure to uranium and other alpha emitters at the national level. It demonstrates the importance of exposure assessment for

  16. Ore reserve calculations of a sedimentary uranium deposit in Figueira, PR-Brazil

    International Nuclear Information System (INIS)

    The are reserve calculations of a sedimentary uranium deposit in Figueira-PR-Brazil are presented. The evalution of reserves was based on chemical and/or radiometric analisys from boreholes. Geoestatistical methods were used to study the spacial correlation between radiometric and'in situ' uranium content and to calculate the equivalent uranium content without the need for chemical analysis. To this end, a new method was developed based on the regression between accumulated chemical and radiometric grades as determined by increasing thicknesses defined from the maximum peak of the γ-ray logs. Thus, the effect of non-focalization of the probe and of the continuous logging was eliminated. The system of evalution used was two-dimensional using classical Kriging to calculate thicknesses and accumulations determined using distinct cut-off grades. (Author)

  17. Uranium in soils and water; Uran in Boden und Wasser

    Energy Technology Data Exchange (ETDEWEB)

    Dienemann, Claudia; Utermann, Jens

    2012-07-15

    The report of the Umweltbundesamt (Federal Environmental Agency) on uranium in soils and water covers the following chapters: (1) Introduction. (2) Deposits and properties: Use of uranium; toxic effects on human beings, uranium in ground water and drinking water, uranium in surface waters, uranium in soils, uranium in the air. (3) Legal regulations. (4) Uranium deposits, uranium mining, polluted area recultivation. (5) Diffuse uranium entry in soils and water: uranium insertion due to fertilizers, uranium insertion due to atmospheric precipitation, uranium insertion from the air. (6) Diffuse uranium release from soils and transfer in to the food chain. (7) Conclusions and recommendations.

  18. Heap leaching of clay ish uranium ores; Lixiviacion estatica de minerales arcillosos de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, E.; Sedano, A.

    1973-07-01

    This paper describes an experimental facility, built near El Lobo mine. In it we study the beneficiation of low-grade uranium ore. The mineral has a great amount of clay and fines. The flow-sheet used has four steps: head leaching, ph-ajustement, ion-exchange and participation. We show, also, the most interesting results. (Author)

  19. A study of radon emanation from waste rock at Northern Territory uranium mines

    International Nuclear Information System (INIS)

    Field measurements were made of radon emanation rates from waste rock sources at Ranger, Nabarlek and Rum Jungle, three Northern Territory uranium mine sites. The preliminary mean emanation rate was approximately 50 Bq m-2s-2 per percent ore grade

  20. Statistical model of global uranium resources and long-term availability

    Directory of Open Access Journals (Sweden)

    Monnet Antoine

    2016-01-01

    Full Text Available Most recent studies on the long-term supply of uranium make simplistic assumptions on the available resources and their production costs. Some consider the whole uranium quantities in the Earth's crust and then estimate the production costs based on the ore grade only, disregarding the size of ore bodies and the mining techniques. Other studies consider the resources reported by countries for a given cost category, disregarding undiscovered or unreported quantities. In both cases, the resource estimations are sorted following a cost merit order. In this paper, we describe a methodology based on “geological environments”. It provides a more detailed resource estimation and it is more flexible regarding cost modelling. The global uranium resource estimation introduced in this paper results from the sum of independent resource estimations from different geological environments. A geological environment is defined by its own geographical boundaries, resource dispersion (average grade and size of ore bodies and their variance, and cost function. With this definition, uranium resources are considered within ore bodies. The deposit breakdown of resources is modelled using a bivariate statistical approach where size and grade are the two random variables. This makes resource estimates possible for individual projects. Adding up all geological environments provides a repartition of all Earth's crust resources in which ore bodies are sorted by size and grade. This subset-based estimation is convenient to model specific cost structures.

  1. Low thermal expansion glass ceramics

    CERN Document Server

    1995-01-01

    This book is one of a series reporting on international research and development activities conducted by the Schott group of companies With the series, Schott aims to provide an overview of its activities for scientists, engineers, and managers from all branches of industry worldwide where glasses and glass ceramics are of interest Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated This volume describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization Thus glass ceramics with thermal c...

  2. Reconnaissance examination of the uranium deposits northeast of Winston, Broadwater County, Montana

    Science.gov (United States)

    Becraft, George E.

    1955-01-01

    Anomalous radioactivity and a yellow secondary uranium mineral tentatively identified as carnotite have been found in Tertiary sedimentary rocks about 3 miles northeast of Winston, Mont. The uranium is in tuffs and tuffaceous shales and particularly in beds rich in organic matter. Carnotite(?) was identified from three localities, principally coating fractures but in places part replacing organic material, and anomalous radioactivity without recognizable uranium minerals has been detected at four localities. Six of the seven localities are at approximately the same stratigraphic horizon. The deposits are virtually unexplored and consequently their size and grade are not known. Selected specimens assay as high as 0.36 percent eU. Exploitable deposits of uranium may be found in this area, as well as in similar areas of western Montana that are underlain by Tertiary tuffaceous rocks.

  3. Initiation in the study of uranium recovery from the phosphoric acid

    International Nuclear Information System (INIS)

    The loss of considerable amounts of uranium in the Mexican phosphoric acid industry makes it important to study economic methods of recovery; the studies can serve as a basis for the construction and operation of a pilot plant as a normal preliminary to larger-scale projects. Routine experimental techniques for solvent extraction were employed. Extraction efficiencies of the order of 90-95% were obtained using 0.09-0.18M solutions of a mixture of phosphoric octyl esters applied to 4 and 6M solutions of phosphoric acid (reagent grade) containing uranium in concentrations of 0.05-0.50g of U3O8 per litre of acid. The conclusion was reached that phosphoric octyl esters can be used for recovering uranium in satisfactory quantities from phosphoric acid solutions by means of solvent extraction, and that the uranium can be separated from the solvent by the established procedures. (author)

  4. A review of international uranium mill tailings management practice

    International Nuclear Information System (INIS)

    Uranium tailings management practices adopted in various countries or, more specifically, uranium mining areas, tend to reflect several factors: the age of the mining and milling operation, the mining method (e.g. underground vs open pit), the ore grade, the regional geology, hydrogeology and geochemistry, the topography and geomorphology of the area, climatic conditions, and governmental regulations. Of these, only the last, governmental regulations, are by definition nationalistic in scope. However, even these tend to reflect the other factors which are imposed by nature. As a result of these factors, international mill tailings management strategies vary greatly and include both effluent and non-effluent producing systems, above and below grade disposal schemes, lined and unlined 'ponds' above and below water (both surface water and groundwater) emplacement, 'wet' and 'dry' methods of disposal, and pre-treatment of the gangue in the mill. This paper reviews current (and, where applicable, past) uranium mill tailings management practice(s) in Africa, Australia, Europe and North America in the context of the above factors

  5. Blind River uranium deposits: the ores and their setting

    International Nuclear Information System (INIS)

    In the Blind River area, Proterozoic clastic sedimentary and minor volcanic rocks (Huronian Supergroup) unconformably overlie and transgress northward over dominantly granitic Archean terrane (2500 million years) and are intruded by Nipissing Diabase (2150 million years). Later deformations and metamorphic events are recognized. The Matinenda Formation (basal Huronian) comprises northward-derived arkose, quartzite, and pyritic, uraniferous oligomictic conglomerates, which contain 75 percent of Canada's uranium reserves. Historic grades approximate 2 pounds U3O8/ton (1 kilogram/metric ton), but lower grade material can be mined with increasing price. Some thorium and rare earths have been marketed. The conglomerate beds lie in southeasterly striking zones controlled by basement topography down-sedimentation from radioactive Archean granite. Distribution of monazite relative to uraninite and brannerite and the presence of uranium values in overlying polymictic conglomerates, which truncate the ore beds, indicate that the mineralization is syngenetic, probably placer. The role of penecontemporaneous mafic volcanics is problematical, but these could have been a source for sulphur in the pyrite. Drab-coloured rocks, uranium and sulphide mineralization, and a post-Archean regolith formed under reducing conditions all suggest a reducing environment. Sedimentary features indicate deposition in fast-flowing shallow water and possibly a cold climate. In the upper Huronian (Lorrain Formation), a monazite and iron oxide assemblage associated with red beds suggests a change to oxidizing conditions

  6. High prevalence of HER-2/neu overexpression in female breast cancer among an Iraqi population exposed to depleted uranium

    OpenAIRE

    AL-Dujaily, Esraa A.; Al-Janabi, Asad A; Pierscionek, Tomasz; Yasseen, Akeel A

    2008-01-01

    Background This study aimed to estimate the rate of HER-2/neu (c-erbB2) immunohistochemical overexpression in different histological types of breast cancer found in the middle Euphrates region of Iraq, a region that was exposed to high levels of depleted uranium. HER-2/neu (c-erbB2) overexpression was correlated with common clinicopathological parameters such as age, grade, stage, tumor size and lymph node involvement to determine if any particular biomarker for exposure to depleted uranium c...

  7. Predominance diagrams of uranium and plutonum species in both lithium chloride-potassium chloride eutectic and calcium chloride

    OpenAIRE

    Brown, L. D.; Abdulaziz, R.; Simons, S; Inman, D.; Brett, D.J.L.; Shearing, P. R.

    2013-01-01

    Electro-reduction of spent nuclear fuel has the potential to significantly reduce the amount of high level waste from nuclear reactors. Typically, spent uranium and plutonium are recovered via the PUREX process leading to a weapons-grade recovery; however, electro-reduction would allow spent nuclear fuel to be recovered effectively whilst maintaining proliferation resistance. Here, we pres- ent predominance diagrams (also known as Littlewood diagrams) for both uranium ...

  8. Proterozoic strata-bound uranium deposits of Zambia and Zaire

    International Nuclear Information System (INIS)

    The Katanga System, host to uranium and copper mineralisation, is several thousands of metres thick and rests unconformably on an older complex of crystalline rocks and metasediments and is locally covered by Karoo sandstones or Kalahari sands. The deposition of the Katanga System took place during the Late Proterozoic in a wide complex basin extending from Shaba province in Zaire through a large part of Zambia and into eastern Angola. The sediments were affected by different grades of metamorphism, tectonic events, and by thermal events associated with post-tectonic metamorphism. At the base of Katanga system there are 84 known copper deposits and 42 uranium occurrences. It is suggested that all the known uranium and copper occurrences are of an essentially syngenetic sedimentary origin. The mineralisation is found in the Lower Roan Formation near the base of the Katanga System occurring in rocks produced in similar environmental conditions and thus being stratigraphic controlled, however, their areal distribution is localised producing a regional metal zonation. Many of the uranium occurrences have a typical vein aspect. These transgressive relationships are not inconsistent with a syngenetic origin as evidenced by the vein morphology. (author)

  9. Updated Conceptual Model for the 300 Area Uranium Groundwater Plume

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, John M.; Freshley, Mark D.; Last, George V.; Peterson, Robert E.; Bjornstad, Bruce N.

    2012-11-01

    The 300 Area uranium groundwater plume in the 300-FF-5 Operable Unit is residual from past discharge of nuclear fuel fabrication wastes to a number of liquid (and solid) disposal sites. The source zones in the disposal sites were remediated by excavation and backfilled to grade, but sorbed uranium remains in deeper, unexcavated vadose zone sediments. In spite of source term removal, the groundwater plume has shown remarkable persistence, with concentrations exceeding the drinking water standard over an area of approximately 1 km2. The plume resides within a coupled vadose zone, groundwater, river zone system of immense complexity and scale. Interactions between geologic structure, the hydrologic system driven by the Columbia River, groundwater-river exchange points, and the geochemistry of uranium contribute to persistence of the plume. The U.S. Department of Energy (DOE) recently completed a Remedial Investigation/Feasibility Study (RI/FS) to document characterization of the 300 Area uranium plume and plan for beginning to implement proposed remedial actions. As part of the RI/FS document, a conceptual model was developed that integrates knowledge of the hydrogeologic and geochemical properties of the 300 Area and controlling processes to yield an understanding of how the system behaves and the variables that control it. Recent results from the Hanford Integrated Field Research Challenge site and the Subsurface Biogeochemistry Scientific Focus Area Project funded by the DOE Office of Science were used to update the conceptual model and provide an assessment of key factors controlling plume persistence.

  10. 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.

  11. Uranium distribution in Brazilian granitic rocks. Identification of uranium provinces

    International Nuclear Information System (INIS)

    The research characterized and described uranium enriched granitoids in Brazil. They occur in a variety of tectonic environments and are represented by a variety granite types of distinct ages. It may be deduced that in general they have been generated by partial melting process of continental crust. However, some of them, those with tonality composition, indicate a contribution from mantle derived materials, thus suggesting primary uranium enrichment from the upper mantle. Through this study, the identification and characterization of uranium enriched granite or uranium provinces in Brazil can be made. This may also help identify areas with potential for uranium mineralization although it has been note that uranium mineralization in Brazil are not related to the uranium enrichment process. In general the U-anomalous granitoids are composed of granites with alkaline composition and granite ''sensu strictu'' which comprise mainly of syenites, quartz-syenites and biotite-hornblende granites, with ages between 1,800 - 1,300 M.a. The U-anomalous belongings to this period present high Sr initial ratios values, above 0.706, and high Rb contents. Most of the U-enriched granitoids occur within ancient cratonic areas, or within Early to Mid-Proterozoic mobile belts, but after their cratonization. Generally, these granitoids are related to the border zones of the mobile belts or deep crustal discontinuity. Refs, 12 figs, 3 tabs

  12. Sustainability of uranium mining and milling: toward quantifying resources and eco-efficiency.

    Science.gov (United States)

    Mudd, Gavin M; Diesendorf, Mark

    2008-04-01

    The mining of uranium has long been a controversial public issue, and a renewed debate has emerged on the potential for nuclear power to help mitigate against climate change. The central thesis of pro-nuclear advocates is the lower carbon intensity of nuclear energy compared to fossil fuels, although there remains very little detailed analysis of the true carbon costs of nuclear energy. In this paper, we compile and analyze a range of data on uranium mining and milling, including uranium resources as well as sustainability metrics such as energy and water consumption and carbon emissions with respect to uranium production-arguably the first time for modern projects. The extent of economically recoverable uranium resources is clearly linked to exploration, technology, and economics but also inextricably to environmental costs such as energy/water/chemicals consumption, greenhouse gas emissions, and social issues. Overall, the data clearly show the sensitivity of sustainability assessments to the ore grade of the uranium deposit being mined and that significant gaps remain in complete sustainability reporting and accounting. This paper is a case study of the energy, water, and carbon costs of uranium mining and milling within the context of the nuclear energy chain.

  13. Sustainability of uranium mining and milling: toward quantifying resources and eco-efficiency.

    Science.gov (United States)

    Mudd, Gavin M; Diesendorf, Mark

    2008-04-01

    The mining of uranium has long been a controversial public issue, and a renewed debate has emerged on the potential for nuclear power to help mitigate against climate change. The central thesis of pro-nuclear advocates is the lower carbon intensity of nuclear energy compared to fossil fuels, although there remains very little detailed analysis of the true carbon costs of nuclear energy. In this paper, we compile and analyze a range of data on uranium mining and milling, including uranium resources as well as sustainability metrics such as energy and water consumption and carbon emissions with respect to uranium production-arguably the first time for modern projects. The extent of economically recoverable uranium resources is clearly linked to exploration, technology, and economics but also inextricably to environmental costs such as energy/water/chemicals consumption, greenhouse gas emissions, and social issues. Overall, the data clearly show the sensitivity of sustainability assessments to the ore grade of the uranium deposit being mined and that significant gaps remain in complete sustainability reporting and accounting. This paper is a case study of the energy, water, and carbon costs of uranium mining and milling within the context of the nuclear energy chain. PMID:18505007

  14. Uranium recovery from seawater

    International Nuclear Information System (INIS)

    The present publication describes the development work of a process to recover uranium from seawater and the proposition of a commercial demonstration plant. The essential components of this process are verified in the laboratory scale as well as in some field tests. A detailed engineering design for a model plant in a semi-technical scale to allow field tests in the marine environment is also presented. These field tests are expected to produce more realistic data on the technical and economical feasibility of the proposed technology. Production cost estimates based on state-of-the-art technology lie around 250 Dollar/1b U3O8. However, the effect of a corresponding uranium price increase on electricity costs are comparable to cost increases in coal operated power plants caused by the desulfurisation of coal. Further reductions of the production costs in the range below 150 Dollar/1b U3O8 seem possible through special research efforts in the area of sorber development and concept design. (orig.)

  15. Uranium in river water

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, M.R. (Univ. of Bristol (United Kingdom)); Edmond, J.M. (Massachusetts Inst. of Technology, Cambridge, MA (United States))

    1993-10-01

    The concentration of dissolved uranium has been determined in over 250 river waters from the Orinoco, Amazon, and Ganges basins. Uranium concentrations are largely determined by dissolution of limestones, although weathering of black shales represents an important additional source in some basins. In shield terrains the level of dissolved U is transport limited. Data from the Amazon indicate that floodplains do not represent a significant source of U in river waters. In addition, the authors have determined dissolved U levels in forty rivers from around the world and coupled these data with previous measurements to obtain an estimate for the global flux of dissolved U to the oceans. The average concentration of U in river waters is 1.3 nmol/kg, but this value is biased by very high levels observed in the Ganges-Brahmaputra and Yellow rivers. When these river systems are excluded from the budget, the global average falls to 0.78 nmol/kg. The global riverine U flux lies in the range of 3-6 [times] 10[sup 7] mol/yr. The major uncertainty that restricts the accuracy of this estimate (and that of all other dissolved riverine fluxes) is the difficulty in obtaining representative samples from rivers which show large seasonal and annual variations in runoff and dissolved load.

  16. Uranium: inexhaustible energy source

    International Nuclear Information System (INIS)

    There exist two social worries in reference with the use of energy, to know, the first is the availability of energy resources for the near future, in terms that the main energy sources at the present, petroleum has a foreseeable limit, and the other, the possible negative effects that the use of fossil fuels, coal among them could have on the environment, the ecology and the life conditions for the human being in general. This two worries take us to consider the availability of uranium, as an alternate energy source for the future of the mankind, considering its lesser ecological impact, since it can be controlled. in this study, the results of several investigations concerning to the abundance, energetic content, extraction costs and the appropiate use of the uranium existing in the earth crust determining the period of time that this fuel can be used as energy source to satisfy the demand of a growing population of human beings on the eart, are re-examined. It is concluded that the utilization of this fuel in the so caled breeder reactors, could satisfy the energy demand for the whole humanity for a long period of time comparable to the life of the sunas a yellow star. (Author)

  17. Gleason grading system

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000920.htm Gleason grading system To use the sharing features on this page, ... score of between 5 and 7. Gleason Grading System Sometimes, it can be hard to predict how ...

  18. Root Graded Lie Superalgebras

    OpenAIRE

    Yousofzadeh, Malihe

    2015-01-01

    We define root graded Lie superalgebras and study their connection with centerless cores of extended affine Lie superalgebras; our definition generalizes the known notions of root graded Lie superalgebras.

  19. DESIGN STUDY FOR A LOW-ENRICHED URANIUM CORE FOR THE HIGH FLUX ISOTOPE REACTOR, ANNUAL REPORT FOR FY 2010

    Energy Technology Data Exchange (ETDEWEB)

    Cook, David Howard [ORNL; Freels, James D [ORNL; Ilas, Germina [ORNL; Jolly, Brian C [ORNL; Miller, James Henry [ORNL; Primm, Trent [ORNL; Renfro, David G [ORNL; Sease, John D [ORNL; Pinkston, Daniel [ORNL

    2011-02-01

    This report documents progress made during FY 2010 in studies of converting the High Flux Isotope Reactor (HFIR) from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum alloy. With axial and radial grading of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in performance to users from the current level. Studies are reported of support to a thermal hydraulic test loop design, the implementation of finite element, thermal hydraulic analysis capability, and infrastructure tasks at HFIR to upgrade the facility for operation at 100 MW. A discussion of difficulties with preparing a fuel specification for the uranium-molybdenum alloy is provided. Continuing development in the definition of the fuel fabrication process is described.

  20. Fast Measurements Of Thermal Diffusivities Of Ceramics

    Science.gov (United States)

    Smith, Marnell; Goldstein, Howard E.

    1988-01-01

    Temperature rises of samples compared with reference sample. Apparatus quickly measures thermal diffusivities of ceramics at high temperatures. Produces data on relative thermal diffusivities of as many as six ceramic specimens per hour. Thermal-diffusivity tester makes it easy to determine thermal diffusivities of ceramics. Pronounced effects of processing parameters on thermal properties of ceramics evaluated quickly.

  1. Contribution to the geochemical knowledge of the uranium-radium and thorium families in the southern Vosges. Applications of some results in the prospecting of uranium deposits; Contribution a la connaissance geochimique des familles uranium-radium et du thorium dans les Vosges meridionales. Application de certains resultats en prospection des gisements d'uranium

    Energy Technology Data Exchange (ETDEWEB)

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

    1962-07-01

    This work's aim is to lead to a more accurate knowledge of the geochemistry of the Uranium-Radium and Thorium families in the Southern Vosges and to apply some of the results to the prospecting of uraniferous deposits: It has been showed: a bond between Calcium-Magnesium and Uranium-Thorium in the calco-alkaline granites. The host minerals of Uranium and Thorium are hornblende, biotite, titanite and epidote. a concentration of Uranium, at present time with secular disequilibrium in a thermal zone where the satellite mineralizations form an epithermal paragenesis. a disequilibrium of the Uranium-Radium family in the supergene minerals of the lead (phosphate and vanadate) showing the present circulations of Uranium. a bond between the radon grade of the spring waters and Uranium-Radium of the rocks. Such a relation allow to realize a prospecting method based on the determination of radioactive gases from the cold spring-waters of a common country. (author) [French] L'etude presentee ici a pour but de conduire a une connaissance plus precise de la geochimie des familles Uranium-Radium et Thorium dans les Vosges meridionales et d'appliquer certains resultats a la prospection des gites uraniferes. Il a ete mis en evidence: une liaison Calcium-Magnesium et Uranium-Thorium dans des granites calco-alcalins. Les mineraux hotes de l'Uranium et du Thorium sont: la hornblende, la biotite, le sphene, l'epidote. une concentration actuelle de l'Uranium en desequilibre seculaire dans une zone thermale ou les mineralisations satellites constituent une paragenese epithermale. un desequilibre de la famille Uranium-Radium dans des mineraux supergenes du plomb (phosphates et vanadates) prouvant les circulations actuelles de l'Uranium. une liaison entre la teneur en Radon des eaux de sources et celle en Uranium-Radium des roches. Une telle liaison permet de realiser une methode de prospection fondee sur le dosage du gaz radioactif des eaux de sources

  2. High-temperature corrosion resistance of ceramics and ceramic coatings

    Energy Technology Data Exchange (ETDEWEB)

    Tortorelli, P.F.

    1996-06-01

    Ceramics and ceramic composites offer the potential to operate fossil energy systems at the higher temperatures necessary for improved energy efficiency and better environmental control. However, because many fossil fuel-derived processes contain sulfur, chlorine, and carbon, as well as oxygen, degradation from high-temperature corrosion and environmental effects arising from reactions of solids with gases and condensable products is a common life-determining factor in operating systems. Ceramic-based products are not immune to such degradation; adequate corrosion resistance must be assured to exploit the technical and economic potential of such materials. This is normally accomplished by using stable, sound oxides that exist in their bulk form, that naturally grow as surface layers upon exposure to an oxidizing environment, or that are deposited as a coating on a susceptible material. It is therefore important to examine the critical issues with respect to more environmental stability of ceramics that have the potential to be corrosion resistant in particular fossil environments. Key aspects include not only chemical compatibility, but the influence of the environment on the mechanical behavior of the ceramic materials. In addition, for coatings, the mechanical reliability of the ceramic is a key issue in that an otherwise corrosion-resistant surface layer must remain sound and adherent in order to provide protection to the underlying substrate. The purpose of this work is to support the development of advanced ceramics and ceramic composites for applications in fossil environments by examining critical issues related to high-temperature corrosion resistance. More specifically, the overall objective of this task is to examine the chemical compatibility and reliability of potentially corrosion-resistant ceramics being developed as protective overcoats and/or structural materials as parts of other work elements funded by the AR&TD Program.

  3. Mechanical and Tribological Properties of Carbon-Based Graded Coatings

    OpenAIRE

    Kot, M; Ł. Major; Lackner, J. M.; K. Chronowska-Przywara; Janusz, M.; Rakowski, W

    2016-01-01

    The paper presents research on coatings with advanced architecture, composed of a Cr/Cr2N ceramic/metal multilayer and graded carbon layers with varying properties from Cr/a-C:H to a-C:N. The microstructure of the coatings was analysed using transmission electron microscopy and Energy Dispersive Spectroscopy, the mechanical properties were tested by nanoindentation, spherical indentation, and scratch testing, and tribological tests were also conducted. The proper selection of subsequent layer...

  4. Sedimentary rocks Uranium in Cerro Largo Province

    International Nuclear Information System (INIS)

    With the aim of the uranium minerals exploration has been carried out several studies by UTE technicians in Cerro Largo Province from 1968 to 1969. In uranium concentration has been found pyrite, phosphate, iron oxides and manganese in uranium. Furthermore in La Divisa Ore were studied concentration Uranium enrichment has been studied in La Divisa ore

  5. Ceramic solvents for the RA-1 Reactor

    International Nuclear Information System (INIS)

    Full text: The new version of fuel for the RA-1 reactor will consist of Zry cladding tubes of 8.2 mm external diameter and, as fuel material, of pellets of 20% enriched U3O8 and Al powder mixture. Because significant internal temperatures are expected (higher than those obtained in plate fuel elements) and that Al oxide formation in the interfaces between U3O8 particles have been detected in experiences outside the reactor and in post-irradiation examinations, the possibility to use ceramic oxides as fissile material solvent, for instance Alumina or Zirconia is explored, since they are inert materials which would avoid fuel transformations and, therefore, possible dimensional and thermal changes. Besides, the oxidation resistance improvement is analyzed through the utilization of UO2 in the Al cermet, since it is more stable in the reaction with Al. The possibility of using the existing utilities to explore these alternatives is considered. This type of fuel is also of interest because it is potentially apt to be used with highly enriched uranium coming from nuclear weapons

  6. OXYGEN ISOTOPE FRACTION ATION IN URANIUM OXIDES

    Institute of Scientific and Technical Information of China (English)

    郑永飞

    1995-01-01

    Thermodynamic oxygen isotope factors for uranium oxides have been calculated by means of the modified increment method.The sequence of 18O-enrichment in the uranium oxides with respect to the common rock-forming minerals is predicted as follows:spineluranium blacks≤coffiniteuranium oxides and water and between the uranium oxides and the other minerals have been obtained for 0-1200℃.The theoretical results are applicable to the isotopic geothermometry of uranium ores when pairing with other gangue minerals in hydrothermal uranium deposits.

  7. Uranium accumulation by Pseudomonas sp. EPS-5028

    International Nuclear Information System (INIS)

    Pseudomonas sp. EPS-5028 was examined for the ability to accumulate uranium from solutions. The uptake of uranium by this microorganism is very rapid and is affected by pH but not by temperature, metabolic inhibitors, culture time and the presence of various cations and anions. The amount of uranium absorbed by the cells increased as the uranium concentration of the solution increased up to 55 mg uranium/g cell dry weight. Electron microscopy indicated that uranium accumulated intracellularly as needle-like fibrils. Uranium could be removed chemically from the cells, which could then be reused a a biosorbent. (orig.)

  8. Growth characteristics of a strain of iron-oxidizing bacterium and its application in bioleaching of uranium ores

    International Nuclear Information System (INIS)

    05B is a strain of iron-oxidizing bacterium which separated from a uranium ore. The effect of temperature, initial pH, inoculation amount and initial total iron concentration on the strain's growth and activities in bioleaching of uranium ores are studied. The results show that the optimum growth temperature is 40-45 degree C, the optimum inoculation pH value being 1.5-1.7, the optimum initial inoculation amount being 10%-20%, and the initial total iron concentration being not more than 5 g/L. 05B is fit for leaching of low grade uranium ores. (authors)

  9. Final environmental statement related to the Minerals Exploration Company, Sweetwater Uranium Project (Sweetwater County, Wyoming). Docket No. 40-8584

    International Nuclear Information System (INIS)

    The proposed action is the issuance of a Source Material License to Minerals Exploration Company (MEC) for the construction and operation of the proposed Sweetwater Uranium Mill in Sweetwater County, Wyoming, with a nominal capacity of 3000 tons (2.7 x 106 kg) per day of uranium ore. As part of this proposal, the applicant proposes also to construct a heap leaching and resin ion-exchange facility to extract uranium from low-grade ores and mine water. Conditions for the protection of the environment are set forth

  10. The Future Contribution of Unconventional Sources of Natural Uranium to Nuclear Fuel Supply. Contribution future des sources conventionnelles d'uranium naturel à l'approvisionnement en combustible nucléaire

    Directory of Open Access Journals (Sweden)

    Boyd B. W.

    2006-11-01

    Full Text Available From what we know about the distribution of uranium in the earth's crust, we can get an indication of how much uranium is likely to occur at concentrations higher than 300 ppm. Although only part of this material is likely to be discovered and brought to production, the amounts are great enough to make it unlikely that much uranium from lower grade deposits will be mined in the next 40 or so years except in special cases. In some circumstances, low grade uranium can be recovered as a by-product or as a product of reworked tailings. Significant amounts are forecast to be recovered from tailings, phosphoric acid and copper leach liquors. It can also be speculated that some uranium may be recovered from coals, shales, granites or carbonatites grading less than 300 ppm. Production from sources in this latter group or from seawater, where uranium would be the prime product, appears unlikely considering the amount of uranium thought to occur in higher concentrotions. De nos connaissances sur la distribution de l'uranium dans la croûte terrestre nous pouvons tirer des indications sur la quantité d'uranium qu'on peut trouver à des concentrations supérieures à 300 ppm. Quoiqu'une partie seulement de celles-ci soit à même d'être découverte et mise en exploitation, les quantités en sont suffisamment grandes pour rendre peu probable l'exploitation des gisements à une teneur plus faible, dans les quarante années à venir ou presque, sauf dans des cas spéciaux. Sous certaines conditions l'uranium à basse teneur peut être récupéré comme sous-produit ou comme produit du retraitement des résidus (tailings et du traitement de l'acide phosphorique et des solutions de lixiviation des minerais de cuivre. On peut aussi prévoir qu'il sera possible d'extraire de l'uranium des charbons, schistes, granites ou carbonatites à une teneur inférieure à 300 ppm. La production à partir des sources de ce dernier groupe ou de l'eau de mer, où l'uranium

  11. High pressure ceramic heat exchanger

    Science.gov (United States)

    Harkins, Bruce D.; Ward, Michael E.

    1998-01-01

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a strengthening reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the strengthening reinforcing member. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

  12. Development of hi-tech ceramics fabrication technology

    International Nuclear Information System (INIS)

    There are some ceramic materials being used in the nuclear energy such as nuclear fuel, coolant pump seals, tritium breeder materials, a high temperature absorber, and the solid electrolyte for recovering tritium. In addition, lots of researches recently have been conducted on the development of highly functional ceramics such as highly efficient shielding materials, functional graded materials and radioactive isotopes-separating materials. Therefore, one of the objectives of this project is to develop ultra-fine and pure powder manufacturing technology. Tritium breeder materials, LiAlO2, Li2ZrO3 and Li2TiO3 were made with a combustion process of mixed fuels that is developed indigenously in this project. Additionally, this study also focused on the development of promising low temperature electrolytes of ceria. By using the ceria powder made by the combustion process of GNP was investigated their sinterability and the electrolytic characteristics. (author). 167 refs., 74 tabs., 91 figs

  13. The Uranium Institute: the first ten years

    International Nuclear Information System (INIS)

    As noted in its Memorandum of Association, the Uranium Institute was founded: to promote the use of uranium for peaceful purposes; to conduct research into uranium requirements, uranium resources and uranium production; to consult for these purposes with governments and other bodies; and to provide a forum for the exchange of information on these matters. A brief account of Institute organisation and activities during the period 1975-1985 is given. (author)

  14. Governing uranium in the United Kingdom

    OpenAIRE

    Berkemeier, Molly; Bowen, Wyn Q.; Hobbs, Christopher; Moran, Matthew

    2014-01-01

    This country report is the first study of uranium governance in the United Kingdom. It explores the UK's approach to regulating natural uranium and provides a historical overview of uranium procurement and usage. The report documents British and Euratom nuclear legislation, regulation and implementation, including export/import and transportation regulations. This case study is part of the large 'Governing Uranium' project on uranium governance, led by DIIS, the Danish Institute for Internati...

  15. Transportable calorimeter measurements of highly enriched uranium

    Energy Technology Data Exchange (ETDEWEB)

    Rudy, C.; Bracken, D.S.; Staples, P.; Carrillo, L.

    1997-11-01

    A sensitive calorimeter has been combined with a small temperature-controlled water bath to compose a transportable system that is capable of measuring multikilogram quantities of highly enriched uranium (HEU). The sample chamber size, 5 in. in diameter by 10 in. high, is large enough to hold sufficient HEU metal or high-grade scrap to provide a measurable thermal signal. Calorimetric measurements performed on well-characterized material indicate that the thermal power generated by 93% {sup 235}U samples with 1.0% {sup 234}U can be measured with a precision of about 1% (1 sigma) for 4-kg samples. The transportable system consists of a twin-bridge calorimeter installed inside a 55-gal. stainless steel drum filled with water with heating and cooling supplied by a removable thermoelectric module attached to the side. Isotopic measurements using high-resolution gamma-ray measurements of the HEU samples and analysis with the FRAM code were used to determine the isotopic ratios and specific power of the samples. This information was used to transform the measured thermal power into grams of HEU. Because no physical standards are required, this system could be used for the verification of plutonium, {sup 238}Pu heat sources, or large quantities of metal or other high-grade matrix forms of HEU.

  16. Biosorption isotherm for uranium recovery

    International Nuclear Information System (INIS)

    An analysis of the biological sorption of uranium on mycelia of Penicillium C-1 is provided. From an isotherm test, a rough estimate of the biomass, required for removal of uranium to a certain level can be attained. The process presents a new approach towards water pollution control and resource recovery. The biosorption method may find its greatest application in solutions of low uranium concentration (100 ppM to 300 ppM) such as in waste mine water or very lean leach solutions

  17. Application of XRF and XRD in the study of ceramics and pottery

    International Nuclear Information System (INIS)

    Ceramic artefacts are made from clay-based mineral and their elemental and mineral compositions tend to vary from one locality to another. The elemental and mineral composition data's besides able to verify the originality of the artifact also helps in regard to provenance, fabrication technology and also manufacturing technique. X-ray fluorescence XRF is a non-destructive technique to identify and quantify elements ranging from sodium (atomic number = 11 to uranium atomic number = 92). The paper also looks into recent advances of this technique in the study of ceramics and pottery. Microfocus XRF, besides able to do qualitative and quantitative elemental analysis, it also can perform accurate elemental mapping. Another aspect there is important in this study is the capability to do in-situ analysis. With the recent introduction of the peltiered-cooled silicon detector, in-situ analysis had become more easily available. X-ray diffraction (XRD) analysis on the other hand, helps to identify correctly the different mineral composition present in the ceramic artifact. This could also help in identifying the type of clay that is used in the manufacturing of these ceramic artifacts as well as its origin. Both x-ray techniques complement each other and are very important tool in the archaeological study of ceramic and pottery samples. (Author)

  18. Uranium project GEO 2 attachment: cronostratigraphy aplied to Uranium research

    International Nuclear Information System (INIS)

    In the article, different sources of information about Uranium stratigraphy from Uruguay have been reviewed. Some results have been presented in Upper Cambrian period and Precambrian era, specially Devonian, Carboniferous and Silurian period

  19. Probing local coordination and oxidation state of uranium in ThO2: U nanostructured

    Science.gov (United States)

    Gupta, Santosh K.; Pathak, N.; Kadam, R. M.

    2015-12-01

    Uranium doped thorium oxide nanoparticle (UDT) was synthesized using citric acid assisted combustion method. The concentration of uranium was varied from 0.5 to 5.0 mol % to investigate the effect of doping concentration on its optical properties. The synthesised UDT powder were characterized systematically using X-ray diffraction (XRD), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) respectively for phase purity, morphology and crystallinity. Pertaining to nuclear industry, UDT is an important material and investigating the local structure of uranium in UDT is interesting as well as challenging because of complexity involved in synthesis of such ceramic powder. We have used time resolved photoluminescence spectroscopy (TRPLS) to probe the local coordination and oxidation state of uranium in UDT. Based on PL emission spectroscopy it was confirmed that uranium stabilizes as UO22+ ion in UDT. Lifetime spectroscopy shows that uranyl ion is not homogenously distributed in UDT lattice; rather it has two different chemical environments. Effect of concentration on PL behaviour shows that, concentration quenching takes place beyond 2.0 mol %; and based on critical distance calculation multipolar interaction was found to be responsible for such non-radiative quenching. As far as application in luminescence industry is concerned PL measurement shows that UDT gives intense green emission under UV excitation.

  20. Alternative Anodes for the Electrolytic Reduction of Uranium Dioxide

    Science.gov (United States)

    Merwin, Augustus

    Reprocessing of spent nuclear fuel is an essential step in closing the nuclear fuel cycle. In order to consume current stockpiles, ceramic uranium dioxide spent nuclear fuel will be subjected to an electrolytic reduction process. The current reduction process employs a platinum anode and a stainless steel alloy 316 cathode in a molten salt bath consisting of LiCl-2wt% Li 2O and occurs at 700°C. A major shortcoming of the existing process is the degradation of the platinum anode under the severely oxidizing conditions encountered during electrolytic reduction. This work investigates alternative anode materials for the electrolytic reduction of uranium oxide. The high temperature and extreme oxidizing conditions encountered in these studies necessitated a unique set of design constraints on the system. Thus, a customized experimental apparatus was designed and constructed. The electrochemical experiments were performed in an electrochemical reactor placed inside a furnace. This entire setup was housed inside a glove box, in order to maintain an inert atmosphere. This study investigates alternative anode materials through accelerated corrosion testing. Surface morphology was studied using scanning electron microscopy. Surface chemistry was characterized using energy dispersive spectroscopy and Raman spectroscopy. Electrochemical behavior of candidate materials was evaluated using potentiodynamic polarization characteristics. After narrowing the number of candidate electrode materials, ferrous stainless steel alloy 316, nickel based Inconel 718 and elemental tungsten were chosen for further investigation. Of these materials only tungsten was found to be sufficiently stable at the anodic potential required for electrolysis of uranium dioxide in molten salt. The tungsten anode and stainless steel alloy 316 cathode electrode system was studied at the required reduction potential for UO2 with varying lithium oxide concentrations. Electrochemical impedance spectroscopy

  1. Uranium and thorium in granitic rocks of northeastern Washington and northern Idaho, with comments on uranium resource potential

    Science.gov (United States)

    Nash, J. Thomas

    1979-01-01

    possibly as minute uraninite grains, whereas in the hornblende suite uranium resides primarily in sphene, zircon, and allanite. Many muscovite-bearing plutons are considered fertile by the following two criteria: high uranium content, and uranium residence in labile phases. The hornblende-bearing granitic plutons are not considered fertile, regardless of uranium content, because uranium resides in refractory phases. Twenty-one sample localities in four plutons are considered highly anomalous according to one or more of the following attributes: (1) Uranium content =115.8 ppm (total population mean plus 1 d). (2) Thorium content =30.3 ppm (mean plus 1 d) and uranium =8.8 ppm (mean). (3) Th/U lower than 1.68 (mean minus 1 d) and uranium content -18.8 ppm. The four identified highly anomalous plutons are, from southwest to northeast, (1) Cretaceous porphyritic quartz monzonite of the Midnite mine; (2) Cretaceous muscovite quartz monzonite east of Deer Lake; (3) Cretaceous quartz monzonite of Hungry Mountain, and (4) Cretaceous quartz monzonite of Granite Pass. The study area is favorable for at least five types of uranium deposits including: intragranitic hydrothermal veins as in the Massif Central, France; intragranitic supergene veins, as at the Daybreak mine; contact zone deposits, as at the Midnite mine; and basal-type sandstone deposits, as at the Sherwood mine. The fifth type is Rossing-type deposits for which the high-grade metamorphic terrane of the Kettle River Range, Ferry County, seems favorable, if sufficient volume of low-tenor rock can be located. The first four deposit types seem most likely in or adjacent to uraniferous plutons, as no other uranium source rocks have been identified in the area. Contact zone deposits and intragranitic hydrothermal veins, both possibly supergene-enriched, and basal-type deposits in Tertiary sandstone and conglomerate, seem most likely to be of economic importance. Exploration and discovery of potential uranium depositions

  2. Are grades really oppressive?

    Institute of Scientific and Technical Information of China (English)

    张心宇

    2015-01-01

    Are grades really oppressive? The broad question's answer is of course open: it varies in different condition and in prerequisites. Like in Daily Californian,"Why Grades are Oppressive", the title tells us it standing: yes, grades are oppressive. In the article, the authors (this article was written by 16 students of the class) pointed out that the grading system has had a violent and powerfully destructive effect on our lives. Because grading focuses our attention on class requirements that we have no say in determination. And this makes many students equate their self-worth with the grades they get in exams. Besides, grades are intimately connected with a larger system of control in community, which trains students to be submissive and not to question or challenge it. In the end, the authors conclude that they should take responsibility for evaluating their own learning process.

  3. Uranium plutonium oxide fuels

    International Nuclear Information System (INIS)

    Uranium plutonium oxide is the principal fuel material for liquid metal fast breeder reactors (LMFBR's) throughout the world. Development of this material has been a reasonably straightforward evolution from the UO2 used routinely in the light water reactor (LWR's); but, because of the lower neutron capture cross sections and much lower coolant pressures in the sodium cooled LMFBR's, the fuel is operated to much higher discharge exposures than that of a LWR. A typical LMFBR fuel assembly is shown. Depending on the required power output and the configuration of the reactor, some 70 to 400 such fuel assemblies are clustered to form the core. There is a wide variation in cross section and length of the assemblies where the increasing size reflects a chronological increase in plant size and power output as well as considerations of decreasing the net fuel cycle cost. Design and performance characteristics are described

  4. 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.

  5. Wear prediction of ceramic-on-ceramic hip artificial joints

    OpenAIRE

    Askari, E; Flores, Paulo; Dabirrahmani, D.; Appleyard, R.

    2015-01-01

    Wear can influence the lifetime and performance of implants and has been found to be a key factor in primary failure of artificial hip joints. The present study aims to present a spatial multibody dynamic model to predict wear in ceramic-on-ceramic hip implants. The problem was formulated by developing a spatial multibody dynamic model of a hip prosthesis taking three-dimensional physiological loading and motion of the human body into account. Then, the Archard wear model was inte...

  6. The uranium cycle

    International Nuclear Information System (INIS)

    In identifying uranium provinces, and, more importantly, mineralized zones within these provinces, it is of paramount importance to attempt to trace the geochemical behaviour of an element through all stages of Earth's evolution. Aspects that need to be addressed in this regard include solar abundance levels and fractionation processes during accretion, changing patterns of crustal evolution, effects of an evolving atmosphere, and the weathering cycle. Abundance patterns and partition coefficients of some of the siderophile elements in mantle rocks lend support to a multistage accretionary process. Lack of a terrestrial record in the first 500 Ma necessitates that lunar models be invoked, which suggests that early fractionation of a mafic/ultramafic magma resulted in an anorthositic crust. Fractionation of the mantle and transfer of materials to the upper levels must be central to any model invoked for development of the crust. Given high heat flow conditions in the early Archaean it would seem inescapable that the process of sea floor spreading and plate tectonics was an ongoing process. If the plate tectonic model is taken back to 3500 Ma, and assuming current speading rates, then about half of the mantle has passed through the irreversible differentiation cycle. Arguments in support of recycled material must be balanced against mantle metasomatism effects. With the associated advent of partial melting of the mantle material a partitioning of minor and trace elements into the melt fraction would take place. The early primitive mafic and ultramafic komatiites exemplify this feature by concentrating U and Th by a factor of 5 compared to chondritic abundances. It is of tantamount importance to understand the generation of the magmas in order to predict which are the 'fertile' bodies in terms of radioelement concentrations. In that the granitoid magmas image their source compositions, the association of high radioelements will primarily be source-dependent. Uranium

  7. Geochemical exploration for uranium

    International Nuclear Information System (INIS)

    The processes and types of dispersion that produce anomalies in stream water, stream sediment, and ground water, and the factors that must be considered in planning and interpreting geochemical surveys are reviewed. Examples of surveys near known deposits show the types of results to be expected. Background values depend mainly on the content of U in rocks of the drainage area. In igneous rocks, U tends to increase with potassium from ultramafic rocks (0.01 ppM) to granitic rocks (1 to 5 ppM). Some alkalic rocks have unusually high contents of U (15 to 100 ppM). Uranium-rich provinces marked by igneous rocks unusually rich in U are recognized in several areas and appear to have a deep crustal or mantle origin. In western U.S., many tertiary tuffaceous rocks have a high U content. Sandstones, limestones, and many shales approximate the crustal abundance at 0.5 to 4 ppM, but black shales, phosphates, and some organic materials are notably enriched in U. Uranium is very soluble in most oxidizing waters at the earth's surface, but is precipitated by reducing agents (organic matter, H2S) and adsorbed by organic material and some Fe oxides. In most surface and ground waters, U correlates approximately with the total dissolved solids, conductivity, and bicarbonate concentration of the water, and with the U content of rocks it comes into contact with. Most surveys of stream water near known districts show distinct anomalies extending a few km to tens of km downstream. A complication with water is the large variability with time, up to x 50, as a result of changes in the ratio of ground water to direct runoff, and changes in rate of oxidation and leaching. Collection and analysis of water samples also pose some difficulties

  8. Creep in electronic ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Routbort, J. L.; Goretta, K. C.; Arellano-Lopez, A. R.

    2000-04-27

    High-temperature creep measurements combined with microstructural investigations can be used to elucidate deformation mechanisms that can be related to the diffusion kinetics and defect chemistry of the minority species. This paper will review the theoretical basis for this correlation and illustrate it with examples from some important electronic ceramics having a perovskite structure. Recent results on BaTiO{sub 3}, (La{sub 1{minus}x}Sr){sub 1{minus}y}MnO{sub 3+{delta}}, YBa{sub 2}Cu{sub 3}O{sub x}, Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x}, (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} and Sr(Fe,Co){sub 1.5}O{sub x} will be presented.

  9. Ceramics for fusion devices

    International Nuclear Information System (INIS)

    Ceramics are required for a number of applications in fusion devices, among the most critical of which are magnetic coil insulators, windows for RF heating systems, and structural uses. Radiation effects dominate consideration of candidate materials, although good pre-irradiation properties are a requisite. Materials and components can be optimized by careful control of chemical and microstructural content, and application of brittle material design and testing techniques. Future directions for research and development should include further extension of the data base in the areas of electrical, structural, and thermal properties; establishment of a fission neutron/fusion neutron correlation including transmutation gas effects; and development of new materials tailored to meet the specific needs of fusion reactors

  10. Ceramic Cerami Turbine Nozzle

    Science.gov (United States)

    Boyd, Gary L.

    1997-04-01

    A turbine nozzle vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The metallic components having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine nozzle vane assembly. The turbine nozzle vane assembly includes an outer shroud and an inner shroud having a plurality of horizontally segmented vanes therebetween being positioned by a connecting member positioning segmented vanes in functional relationship one to another. The turbine nozzle vane assembly provides an economical, reliable and effective ceramic component having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the other component.

  11. Ceramic turbine nozzle

    Science.gov (United States)

    Shaffer, James E.; Norton, Paul F.

    1996-01-01

    A turbine nozzle and shroud assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The metallic components having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine nozzle vane assembly. The turbine nozzle vane assembly includes a plurality of segmented vane defining a first vane segment and a second vane segment. Each of the first and second vane segments having a vertical portion. Each of the first vane segments and the second vane segments being positioned in functional relationship one to another within a recess formed within an outer shroud and an inner shroud. The turbine nozzle and shroud assembly provides an economical, reliable and effective ceramic component having a preestablished rate of thermal expansion being less than the preestablished rate of thermal expansion of the other component.

  12. In situ leaching of uranium

    International Nuclear Information System (INIS)

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

  13. National Uranium Resource Evaluation: Torrington Quadrangle, Wyoming and Nebraska

    Energy Technology Data Exchange (ETDEWEB)

    Seeland, D

    1982-09-01

    The Torrington 1/sup 0/ x 2/sup 0/ Quadrangle in southeastern Wyoming and western Nebraska was evaluated to identify areas favorable for the occurrence of uranium deposits likely to contain 100 tons of uranium with an average grade of not less than 100 ppM (0.01 percent) U/sub 3/O/sub 8/. Almost all uranium occurrences reported in the literature were visited and sampled. Geochemical analyses of rock samples collected during the study were used in the evaluation. Hydrogeochemical and stream-sediment analyses were not available. Aerial-radiometric, and helium soil-gas surveys were analyzed. Much of the quadrangle is covered by Tertiary rocks. To assess the uranium potential of the Tertiary and pre-Tertiary rocks 270 well logs were studied and both contour and geologic maps made of the pre-Oligocene surface east and north of the Laramie Mountains. Five environments favorable for uranium deposits were outlined. The first is in the coarse-grained arkosic sandstone facies of the Wasatch Formation and the Lebo Member of the Fort Union Formation in the southern Powder River Basin. The second is in the Wind River Formation in the Shirley Basin, a stratigraphic and lithologic equivalent of the Wasatch. The third is the Lower Cretaceous Cloverly Formation in the northeastern part of the quadrangle. The fourth is in the Upper Cretaceous Lance (Laramie) Formation and the Fox Hills Sandstone in the southeastern corner of the quadrangle. The fifth favorable environment is in Precambrian rocks in the Laramie Mountains and Hartville uplift.

  14. Low Thermal Expansion Glass Ceramics

    CERN Document Server

    Bach, Hans

    2005-01-01

    This book appears in the authoritative series reporting the international research and development activities conducted by the Schott group of companies. This series provides an overview of Schott's activities for scientists, engineers, and managers from all branches of industry worldwide in which glasses and glass ceramics are of interest. Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated. This new extended edition describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics. The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions. Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization. Thus g...

  15. The ceramic gas electron multiplier

    Energy Technology Data Exchange (ETDEWEB)

    Tosson, Amir; Fleck, Ivor [Siegen University, Siegen (Germany); Collaboration: LCTPC-Deutschland-Collaboration

    2015-07-01

    The Gas Electron Multiplier (GEM) has been proven to fulfill the demands of high energy physics experiments. Effective gain and resistance to the electrical sparks are significant issues to be investigated. A new type of GEM, made out of ceramic, has been produced and results from measurements with this type of GEM are presented. Advantages of ceramic material are its very good stability versus change in temperature and its electrical properties. Using Ar-CO{sub 2}(80-20 %) gas mixture and a X-ray source, the gain of the ceramic GEMs is measured and compared with the one for CERN GEMs. These results assure the possibility of using the ceramic GEMs for high-luminosity experiments.

  16. Interview regarding Uzbekistan Uranium Reserves

    International Nuclear Information System (INIS)

    In his first extensive interview, Nicolay I. Kuchersky, President of Kyzylkumredmetzoloto and General Director of the Novoi Mining and Metallurgy Combine, discusses the business of mining uranium in Uzbekistan. This is a companion article following one that took an in-depth look at this newly independent country's activities in uranium mining. The president of the responsible organization discusses plans, wages, and interactions with the western world

  17. Uranium glass in museum collections

    OpenAIRE

    Lopes, Filipa

    2008-01-01

    The presence of uranium glass objects in museum and private collections has raised radiation protection concerns resulting from possible exposure to ionizing radiation emitted by this type of object. Fourteen glass objects with different uranium contents were studied. Dose rates (β + γ radiation) were measured with a beta/gamma probe at several distances from the glass objects. In general the determined dose rates did not raise any concern as long as some precautions were taken. Rado...

  18. Inhalation hazards to uranium miners

    International Nuclear Information System (INIS)

    This project is investigating levels of uranium mine air contaminants, using both large and small experimental animals to model human respiratory system disease. Lung cancer and deaths by degenerative lung disease have reached epidemic proportions among uranium miners, but the cause-effect relationships for these diseases are based on inadequate epidemiological data. This project identifies agents or combinations of agents (both chemical and radiological) and their exposure levels that produce respiratory tract lesions, including respiratory epithelial carcinoma, pneumonconiosis and emphysema

  19. The Espinharas uranium occurrence, Brazil

    International Nuclear Information System (INIS)

    Nuclam has been exploring for uranium in Brazil since 1976. During this period one uranium ore body has been found in the vicinity of Espinharas, a village in Paraiba State, northeast Brazil. According to present knowledge, the mineralized ore body is caused by metasomatic action. The history of discovery and the exploration work until the end of 1979 is given, showing the conceptual change with increasing knowledge of the mineralized zone. (author)

  20. Removal of Uranium and Thorium from Kvanefjeld Rare Earth Intermediate Product

    International Nuclear Information System (INIS)

    Rare earth elements are commonly encountered in close geological association with radioactive minerals. In particular, thorium is often found in the same minerals as rare earth elements, making their combined treatment necessary. The paper discusses the metallurgical flowsheet developed for the Kvanefjeld rare earth and uranium deposit located in southern Greenland. The Kvanefjeld and associated deposits are well recognized as one of the largest rare earth and uranium deposits in the world. The minerals which contain the rare earth elements also contain economically viable amounts of uranium and potentially economically viable amounts of thorium. Metallurgical studies using flotation have been successful in producing a high grade concentrate which consists of 13% rare earth oxide, 0.2% triuranium octaoxide and 0.8% thorium. Due to the unique nature of the minerals contained within the deposit, a customized hydrometallurgical flowsheet was developed to treat the concentrate. The hydrometallurgical flowsheet has been well tested and is capable of producing a high grade mixed rare earth product which is very low in uranium and thorium. A separate uranium oxide product can also be produced using commercially established solvent extraction. The Kvanefjeld project is currently at the feasibility study stage, with metallurgical designs of both the concentrator and hydrometallurgical plant well advanced. The paper discusses the metallurgical flowsheet and show the deportment of NORM throughout the flowsheet. The issues of NORM deportment and strategies for removal and safe disposal are also discussed. (author)

  1. Mineralogical, radiographic and uranium leaching studies on the uranium ore from Kvanefjeld, Ilimaussaq Complex, South Greenland

    International Nuclear Information System (INIS)

    102 samples of low-grade uranium ore from 70 drill holes at Kvanefjeld, Ilimaussaq alkaline intrusion, South Greenland were studied by means of autoradiography, fission-track investigations, microscopy, microprobe analyses and uraniumleaching experiments. The principal U-Th bearing mineral, steenstrupine, and several less common uranium minerals are disseminated in lujavrite (nepheline syenite) and altered volcanic rocks. Steenstrupine has average composition Nasub(6.7)Hsub(x)Casub(1.0) (REE+Y)sub(5.8)(Th,U)sub(0.5)(Mnsub(1.6)Fesub(1.8)Zrsub(0.3)Tisub(0.1)Alsub(o.2))Sisub(12)Osub(36)(Psub(4.3)Sisub(1.7))Osub(24)(F,OH) x nHsub(2)O; n and x are variable. It either is of magnetic origin (type A) or connected with metasomatic processes (type B), or occurs in late veins (type C). Preponderance of grains are metamict (usually 2000-5000 ppm U3O8) or altered (usually above 5000 ppm U3O8), sometimes zoned with both components present. Occasionally they are extremely altered with U content falling to 500-5000 ppm U3O8 and local accumulations of high-U minerals formed. Replacement by crystalline monazite (+- metamict uranothorite and other components) is locally important. Uranium recovery by carbonate leaching (NaHCO3+Na2CO3+O20) depends both on alteration of steenstrupine and on hydration of parent rocks. Yield is between 98 and 50%, the average U concentration in the examined rock around 350 ppm U. (author)

  2. Nano-Ceramic Coated Plastics

    Science.gov (United States)

    Cho, Junghyun

    2013-01-01

    Plastic products, due to their durability, safety, and low manufacturing cost, are now rapidly replacing cookware items traditionally made of glass and ceramics. Despite this trend, some still prefer relatively expensive and more fragile ceramic/glassware because plastics can deteriorate over time after exposure to foods, which can generate odors, bad appearance, and/or color change. Nano-ceramic coatings can eliminate these drawbacks while still retaining the advantages of the plastic, since the coating only alters the surface of the plastic. The surface coating adds functionality to the plastics such as self-cleaning and disinfectant capabilities that result from a photocatalytic effect of certain ceramic systems. These ceramic coatings can also provide non-stick surfaces and higher temperature capabilities for the base plastics without resorting to ceramic or glass materials. Titanium dioxide (TiO2) and zinc oxide (ZnO) are the candidates for a nano-ceramic coating to deposit on the plastics or plastic films used in cookware and kitchenware. Both are wide-bandgap semiconductors (3.0 to 3.2 eV for TiO2 and 3.2 to 3.3 eV for ZnO), so they exhibit a photocatalytic property under ultraviolet (UV) light. This will lead to decomposition of organic compounds. Decomposed products can be easily washed off by water, so the use of detergents will be minimal. High-crystalline film with large surface area for the reaction is essential to guarantee good photocatalytic performance of these oxides. Low-temperature processing (nano-ceramic coatings (TiO2, ZnO) on plastic materials (silicone, Teflon, PET, etc.) that can possess both photocatalytic oxide properties and flexible plastic properties. Processing cost is low and it does not require any expensive equipment investment. Processing can be scalable to current manufacturing infrastructure.

  3. Novel Synthesis of Ceramic Films

    Institute of Scientific and Technical Information of China (English)

    K.L.Choy

    2007-01-01

    1 Results There is an increasing demand for producing high performance ceramic films at a reduced cost. This paper describes an innovative and cost-effective method of producing nanostructured ceramic films based on Electrostatic Spray Assisted Vapour Deposition (ESAVD). ESAVD is a variant of chemical vapour deposition process which involves spraying atomised charged precursor droplets across an electric field where the precursor undergo decomposition and heterogeneous chemical reaction near the heat...

  4. A Simple Alternative to Grading

    Science.gov (United States)

    Potts, Glenda

    2010-01-01

    In this article, the author investigates whether an alternative grading system (contract grading) would yield the same final grades as traditional grading (letter grading), and whether or not it would be accepted by students. The author states that this study demonstrated that contract grading was widely, and for the most part, enthusiastically…

  5. Overview of Canada's uranium industry

    International Nuclear Information System (INIS)

    This paper places Canada's uranium industry in its international context. Most uranium, except that produced in the United States, is traded internationally. A brief history of the industry worldwide is given to show how the principal producing areas have fared to date. The industry is young, highly cyclical, and still far from achieving stability. Uranium is a single end-use commodity, entirely dependent on the generation of electricity in nuclear stations, and is without price elasticity: lowering the price does not increase demand. The typical nuclear fuel processing chain has not encouraged or led to much vertical integration. Uranium is subject to more governmental control than any other commodity. The principal market is located in the industrial countries of western Europe, the United States, Canada, and the far east. The uranium supply-demand situation is reviewed, including the current and near-term oversupply and the longer term outlook to 1995. The major negative impact of reactor cancellations and deferments in the United States is discussed. Because of the difficulty in getting reactors on line, it has become easier to forecast the demand for uranium over the next 10 years. It is more difficult to predict how that demand will be met from the more than ample competing sources. Canada's potential for supplying a significant portion of this demand is considered in relation to producers and potential new producers in other countries

  6. Uranium - resources development and availability

    International Nuclear Information System (INIS)

    Australia possesses a major portion of the world's low cost uranium and it is confidently expected that further exploration will delineate yet more reserves. The level of such exploration and the rate of development of new production will remain critically dependent on world market developments. For the foreseeable future all development will be dedicated to supplying the export market. Australian government policies for uranium take account of both domestic and international concerns. With Australia, the policies act to protect the interests of the Aboriginal people affected by uranium production. In response to national interests and concerns, foreign investment in uranium production ventures is regulated in a manner which requires Australian control but allows a measure of foreign equity. Environmental concerns are recognized and projects may only be approved after comprehensive environmental protection procedures have been complied with. Without these policies public acceptability, which provides the foundations for long-term stability of the industry, would be prejudiced. On the world scene, Australia's safeguards policy serves to support international nuclear safeguards and, in particular, to honour its obligations under the Nuclear Non-Proliferation Treaty. Export policy requires that reasonable sales contract conditions apply and that fair negotiated market prices are obtained for Australia's uranium. Australia's recent re-emergence as a major producer and exporter of uranium is convincing testimony to the success of these policies. (author)

  7. Uranium exploration planning and practice

    International Nuclear Information System (INIS)

    The International Atomic Energy Agency has long had an interest in providing manuals and guidebooks to assist workers in the most effective use of uranium exploration methods and techniques. These have been widely used by the mineral industry around the world. Little has been done, however, to guide and assist senior levels of management of national Atomic Energy Commissions or Geological Surveys in planning for and managing their uranium exploration had development programmes. The nature of uranium, and its potential military use makes it a commodity requiring special consideration. On the other hand, the fact that it is a mineral fuel commodity that is explored for and mined like other mineral commodities presents management with problems of mineral economics unlike those normally faced by government scientific organizations. In order to address these questions, the IAEA convened a Advisory Group meeting in December 1988, to discuss the requirements for uranium exploration planning and practice, from the point of view of national policy and strategy. The six advisors, three observers and four Agency staff members brought to the discussions a wealth of experience in government and in the minerals industry dealing with uranium. The present document, comprising 8 papers as well as transcribed discussions on each, should be of interest and value to senior government planners charged with the task of regulating and controlling their country's uranium development. Refs, figs and tabs

  8. Uranium retrieval support, storage, and marketing

    International Nuclear Information System (INIS)

    The United States Department of Energy is implementing a stewardship approach to management of uranium assets. This life-cycle approach to managing uranium addresses current needs in the context of a long-term strategy. In June 1998, the United States Department of Energy established the Uranium Management Group. The mission of the UMG is to safely collect and store commercially viable uranium from various DOE facilities at a central location. The Oak Ridge Operations Office, in Oak Ridge, Tennessee, was given the task to establish a facility for the storage of these uranium materials. Materials collected are non-waste uranium and packaged to allow transport and long-term storage. Coordination of uranium management under the Uranium Management Group offers significant opportunities for sayings through improved planning and efficiency and creates an environmentally sound approach for the storage and reuse of excess uranium. (author)

  9. Ceramic materials and growth factors

    Energy Technology Data Exchange (ETDEWEB)

    Ohgushi, H.; Yoshikawa, T.; Okumura, M.; Nakajima, H.; Takakura, Y. [Nara Medical Univ. (Japan). Dept. of Orhtopaedic Surgery; Dohi, Y. [Nara Medical Univ. (Japan). Dept. of Public Health; Noshi, T.; Ikeuchi, M. [Nara Medical Univ. (Japan). Dept. of Oral and Maxillofacial Surgery

    2001-07-01

    Recently, many types of growth factors have been purified and used for promoting cell differentiation cascade. The activity of growth factors can be detected in vitro such as culture condition. However, the activity is difficult to detect when these factors are locally administered in vivo, because these dissipate soon after the administration. In order to retain growth factors in local milieu, these can be incorporated with biocompatible porous ceramic materials. Such ceramic/factors composites when implanted in vivo, can trigger certain types of cell differentiation cascade resulted in new tissue formation and tissue regeneration. The paper describes the ceramic / growth factors composites especially hydroxyapatite ceramic (HA) / bone morphogenetic protein (BMP) composite to induce osteoblastic differentiation of mesenchymal stem cells. The HA/BMP composite supported the osteoblastic differentiation on the HA surface and finally resulted in bone bonding to the HA. When the marrow mesenchymal stem cells (MSCs) were impregnated in pore areas of HA ceramics, the composites showed more and rapid bone formation than the HA/BMP and HA/MSCs composite, indicating the synergistic effect of BMP and MSCs. These findings indicate the importance of ceramic surface to evoke osteoblastic differentiation as well as to capture the molecules of growth factors for the cell differentiation. (orig.)

  10. Assessment of uranium exposure in a community near former uranium mining and milling

    International Nuclear Information System (INIS)

    The northern region of Karnes County, Texas has been the site of extensive mining and milling of uranium-238 (238U) for over 30 years. Measurements of 238U were conducted to test the hypothesis that past mining/milling efforts have increased the environmental burden of 238U in local residential areas. 238U concentrations and lead isotope ratios were measured by ICP-MS in soil, plant tissues, household furnace filters, carpet dusts and drinking water. Soil samples (n=75) were collected from the yards of previously studied homes at the surface and 30 cm subsurface. From each home carpet vacuums, filter entrapments and dust swabs were collected (total n=15) as were water wells samples when available (n=7). A site located over 8 miles south of the study area and with no history of mining or milling facilities was found to be consistently and statistically (p238U contamination in the study area from high grade imported ore. The water sample near the largest mining/milling operation compared to the control site, indicating leaching into the groundwater. Analysis of dust samples indicates indoor contamination as 238U was as much as 10X higher in homes from the mining/milling areas compared to the control region. Data thus far indicates that uranium contamination from mining/milling activities is likely to be the cause of the previously documented biological effects and suggests increased health risks for these residents

  11. Uranium separations using extraction chromatography

    International Nuclear Information System (INIS)

    In the analysis of environmental samples for uranium and thorium pollutants and at natural levels for the dating of geological samples there was felt a need to develop better uranium and thorium, separation procedures to replace the established anion exchange method used at AEA Technology plc. This was the first aim of the PhD research. Separation of uranium from thorium prior to measurement of the isotopes by alpha spectrometry was necessary due to the similar alpha energies of 234U and 230Th. TRU and UTEVA extraction chromatography resins (EIChroM Industries) were investigated as potential replacements to the anion exchange separation method. The resins are claimed by EIChroM to offer the advantage of providing an actinide specific separation while reducing the separation time from 2 to 0.5 days; the volume of acidic waste produced by a factor of 3, therefore, the cost of analysis was reduced. A uranium and thorium separation procedure using the UTEVA extraction chromatography resin was developed. The uranium and thorium were sorbed by the UTEVA resin from 2M nitric acid. The thorium was then eluted from the resin with 5M hydrochloric acid and the uranium with 0.02M hydrochloric acid. The separation procedure was then evaluated using uraninite ore, coral, granite and lake sediment reference materials. The uranium and thorium concentrations and the 234U/238U and 230Th/234U activity ratio values determined for the reference material were in good agreement with certified values. The presence of plutonium was found to interfere with the measurement of uranium and thorium by alpha spectrometry. This was due to the similar alpha energies of uranium, thorium and plutonium. The co-elution of plutonium with uranium and thorium from the UTEVA resin was prevented by the inclusion of a reduction step using iron (II) sulphamate. The resulting plutonium (III) was not retained by the UTEVA column. The chemical recoveries for the procedure were similar to those for anion

  12. Assessment of gamma radiation exposure to drivers (contractual) engaged with transporting of uranium ore in uranium mines at Narwapahar Mines, India

    International Nuclear Information System (INIS)

    Due to radioactive nature of uranium ore and tailings sand, it is essential to assess the exposure of drivers and helpers, those are continuously engaged with transporting of it. The external exposure is due to gamma radiation, emitted by uranium progeny and its magnitude is therefore directly related to the ore grade. The major gamma emitters in the series are 214Pb and 214Bi. After uranium recovery in ore processing areas the waste generated in mill contains same magnitude of gamma emitters. Tailings sand is the waste generated from mill area, which is used for back filling in underground mine. This paper presents the results of estimation of external gamma radiation levels during transport and assesses the radiation dose to drivers and helpers

  13. Discussion on geological features and genesis of Chulute uranium metallogenetic region of North Hanggay Province in Mongolia

    International Nuclear Information System (INIS)

    Chulute uranium metallogenetic region is situated in the northern part of North Hanggay Province in Mongolia. Geotectonically, it is located at the very western end of Mongolia-Transbaikal fold system. The granite with elevated uranium content is widely developed in this region, where the uranium content in the granite aged from Later Triassic to Early Jurassic ranges from 5 x 10-6 to 6 x 10-6. Due to the neotectonic activation, quaternary palaeo-valleys that incised the basement were formed on the basement granite and were filled with organic matter-rich clastic sediments and basalt crusts. The palaeo-valley type uranium mineralization (Dajinhe, Bayaer and Shuer uranium occurrences) is discovered in the two palaeo-valleys which incised the granitoids. Of them, Shuer uranium occurrence has been studied more in detail. An ore-body with the thickness from 9.1 m to 19.75 m has been found in an area with the width of 500 m, and the uranium grade ranging from 0.01% to 0.05%. The uranium mineralization occurs in the bleached and limonitized grey loam and clayey soil and sand which bear rich calliferous plant debris and lamella of black mudstones. Coffinite is the uranium mineral. The uranium resources in Shuer deposit has been proven as 2500 t. The total predictive resources in above mentioned two palaeo-valleys reach as much as 15000-16000 t (P2). The uranium mineralization in this region is characterized by young mineralization age and adjacent sources. The ore formation is possibly related to the surface thermal field which is originated from the eruption of the basaltic magmas. (authors)

  14. Total-Count Calibration Blocks for use in uranium Exploration

    DEFF Research Database (Denmark)

    Løvborg, Leif

    Transportable calibration blocks for field scintillometers and borehole probes were manufactured from concrete and installed at calibration sites in Denmark and Greece. The concrete mixes were prepared from aggregates of quartz sand and crushed uranium-thorium ore. Hater-reducing agents and silica...... dust added to the cement paste produced concretes of acceptable porosity and pore structure. The content of ore was adjusted to provide block grades of approximately 2, 140, and 540 units of radioelement concentration (Ur). Thorium was estimated to contribute 0.39 ± 0.02 Ur per ppm Th. The adopted...

  15. Uranium uptake by hydroponically cultivated crop plants

    Energy Technology Data Exchange (ETDEWEB)

    Soudek, Petr; Petrova, Sarka [Laboratory of Plant Biotechnologies, Joint Laboratory of Institute of Experimental Botany AS CR, v.v.i. and Crop Research Institute, v.v.i., Rozvojova 263, 162 05 Prague 6 (Czech Republic); Benesova, Dagmar [Laboratory of Plant Biotechnologies, Joint Laboratory of Institute of Experimental Botany AS CR, v.v.i. and Crop Research Institute, v.v.i., Rozvojova 263, 162 05 Prague 6 (Czech Republic); Faculty of Environment Technology, Institute of Chemical Technology, Technicka 5, 166 28 Prague 6 (Czech Republic); Dvorakova, Marcela [Laboratory of Plant Biotechnologies, Joint Laboratory of Institute of Experimental Botany AS CR, v.v.i. and Crop Research Institute, v.v.i., Rozvojova 263, 162 05 Prague 6 (Czech Republic); Vanek, Tomas, E-mail: vanek@ueb.cas.cz [Laboratory of Plant Biotechnologies, Joint Laboratory of Institute of Experimental Botany AS CR, v.v.i. and Crop Research Institute, v.v.i., Rozvojova 263, 162 05 Prague 6 (Czech Republic)

    2011-06-15

    Hydroponicaly cultivated plants were grown on medium containing uranium. The appropriate concentrations of uranium for the experiments were selected on the basis of a standard ecotoxicity test. The most sensitive plant species was determined to be Lactuca sativa with an EC{sub 50} value about 0.1 mM. Cucumis sativa represented the most resistant plant to uranium (EC{sub 50} = 0.71 mM). Therefore, we used the uranium in a concentration range from 0.1 to 1 mM. Twenty different plant species were tested in hydroponic solution supplemented by 0.1 mM or 0.5 mM uranium concentration. The uranium accumulation of these plants varied from 0.16 mg/g DW to 0.011 mg/g DW. The highest uranium uptake was determined for Zea mays and the lowest for Arabidopsis thaliana. The amount of accumulated uranium was strongly influenced by uranium concentration in the cultivation medium. Autoradiography showed that uranium is mainly localized in the root system of the plants tested. Additional experiments demonstrated the possibility of influencing the uranium uptake from the cultivation medium by amendments. Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba up to 2.8 times or 1.9 times, respectively. Phosphate deficiency increased uranium uptake up to 4.5 times or 3.9 times, respectively, by Brassica oleracea and S. alba. In the case of deficiency of iron or presence of cadmium ions we did not find any increase in uranium accumulation. - Highlights: > The uranium accumulation in twenty different plant species varied from 0.160 to 0.011 mg/g DW. > Uranium is mainly localized in the root system. > Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba. > The phosphates deficiency increase the uranium uptake.

  16. Micromechanical Simulation of Thermal Cyclic Behavior of ZrO2/Ti Functionally Graded Thermal Barrier Coatings

    OpenAIRE

    Hideaki Tsukamoto

    2015-01-01

    This study numerically investigates cyclic thermal shock behavior of ZrO2/Ti functionally graded thermal barrier coatings (FG TBCs) based on a nonlinear mean-field micromechanical approach, which takes into account the time-independent and dependent inelastic deformation, such as plasticity of metals, creep of metals and ceramics, and diffusional mass flow at the ceramic/metal interface. The fabrication processes for the FG TBCs have been also considered in the simulation. The effect of creep...

  17. Chapter 6. Uranium extraction possibilities from natural uranium-bearing waters of complex salt composition. 6.1. Some uranium extraction methods from natural uranium-bearing waters of complex salt composition

    International Nuclear Information System (INIS)

    Present article is devoted to various uranium extraction methods from natural uranium-bearing waters of complex salt composition. Various uranium extraction methods from natural uranium-bearing waters of complex salt composition were described.

  18. Fully ceramic microencapsulated fuels. Characteristics and potential LWR applications

    International Nuclear Information System (INIS)

    This paper summarizes the characteristics of the fully ceramic microencapsulated (FCM) fuel concept and two potential light water reactor (LWR) applications of FCM fuels: for actinide management and as an accident tolerant fuel (ATF). Recent progress in FCM fuel development includes production of uranium mononitride kernels, fabrication of FCM pellets and pins, and irradiation testing of matrix samples and FCM pellets. Potential applications of FCM fuel in LWRs appear promising based upon studies performed by several organizations; however, further efforts are needed to investigate various design aspects in further detail and explore promising new areas of research such as new fuel pin and assembly designs or alternate materials of interest. Current challenges in FCM fuel development and LWR applications for FCM fuels include low heavy metal fuel loading densities and increased uncertainties in analysis due to several different factors. Overall, LWR FCM concepts appear feasible for both actinide management and as an ATF. (author)

  19. Ferroelectric ceramics in a pyroelectric accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Shchagin, A. V., E-mail: shchagin@kipt.kharkov.ua [Kharkov Institute of Physics and Technology, Kharkov 61108 (Ukraine); Belgorod State University, Belgorod 308015 (Russian Federation); Miroshnik, V. S.; Volkov, V. I. [Kharkov Institute of Physics and Technology, Kharkov 61108 (Ukraine); Oleinik, A. N. [Belgorod State University, Belgorod 308015 (Russian Federation)

    2015-12-07

    The applicability of polarized ferroelectric ceramics as a pyroelectric in a pyroelectric accelerator is shown by experiments. The spectra of X-ray radiation of energy up to tens of keV, generated by accelerated electrons, have been measured on heating and cooling of the ceramics in vacuum. It is suggested that curved layers of polarized ferroelectric ceramics be used as elements of ceramic pyroelectric accelerators. Besides, nanotubes and nanowires manufactured from ferroelectric ceramics are proposed for the use in nanometer-scale ceramic pyroelectric nanoaccelerators for future applications in nanotechnologies.

  20. Graded cluster algebras

    OpenAIRE

    Grabowski, Jan

    2015-01-01

    In the cluster algebra literature, the notion of a graded cluster algebra has been implicit since the origin of the subject. In this work, we wish to bring this aspect of cluster algebra theory to the foreground and promote its study. We transfer a definition of Gekhtman, Shapiro and Vainshtein to the algebraic setting, yielding the notion of a multi-graded cluster algebra. We then study gradings for finite type cluster algebras without coefficients, giving a full classification. Translating ...