WorldWideScience

Sample records for compounds silver uranium

  1. METHOD OF RECOVERING URANIUM COMPOUNDS

    Science.gov (United States)

    Poirier, R.H.

    1957-10-29

    S>The recovery of uranium compounds which have been adsorbed on anion exchange resins is discussed. The uranium and thorium-containing residues from monazite processed by alkali hydroxide are separated from solution, and leached with an alkali metal carbonate solution, whereby the uranium and thorium hydrorides are dissolved. The carbonate solution is then passed over an anion exchange resin causing the uranium to be adsorbed while the thorium remains in solution. The uranium may be recovered by contacting the uranium-holding resin with an aqueous ammonium carbonate solution whereby the uranium values are eluted from the resin and then heating the eluate whereby carbon dioxide and ammonia are given off, the pH value of the solution is lowered, and the uranium is precipitated.

  2. The toxicology of uranium compounds

    International Nuclear Information System (INIS)

    Brickner, D.

    1988-11-01

    This review of literature presents and criticises the current knowledge relevant to risk assessment in cases of human exposure to natural uranium compounds due to industrial accidents. The major risk of high uranium exposure is renal-tubular damage which may lead to acute renal insufficiency and death. Radiation damage is not expected in these circumstances. In this review the metabolism of uranium in the body, the health effects and the possible medical treatment are discussed, with an emphasis on relatively large exposure of short duration. The current ICRP lung model does not represent all the factors affecting the kinetics of uranium oxides in the respiratory tract. The significance of these factors, not represented by the model, for risk assessment in such exposures, is not known. The current recommendations for treatment are not scientifically based. Further investigations are urgently needed to enable a rational medical preparadness

  3. Process for uranium recovery in phosphorus compounds

    International Nuclear Information System (INIS)

    Demarthe, J.M.; Solar, Serge.

    1980-01-01

    Process for uranium recovery in phosphorus compounds with an organic phase containing a dialkylphosphoric acid. A solubilizing agent constituted of an heavy alcohol or a phosphoric acid ester or a tertiary phosphine oxide or octanol-2, is added to the organic phase for solubilization of the uranium and ammonium dialkyl pyrophosphate [fr

  4. Effects of uranium compounds on skin

    International Nuclear Information System (INIS)

    Rey, B.M. de

    1982-12-01

    The following uranium compounds were topically applied to the dorsal skin of 35 day-old Wistar rats (60 g, male): uranium dioxide, uranyl nitrate, uranyl acetate, ammonium uranyl tricarbonate and ammonium diuranate. Percutaneous absorption was mediated with the aid of a vehicle and known quantities of various particle-sized batches of uranium compounds were directly implanted in the subcutaneous tissue. Animals were sacrificed 3, 6, 24 and 48 hours after implantation. Subcutaneous tissue and muscle underneath the implantation site were anlaysed by light and electron microscopy. A Cameca 322 X-ray microanalyzer was used to analyze uranium traces in calcified tissue (bones and teeth) and kidneys. A steady loss in body weight was observed in animals given high concentration of uranyl nitrate and ammonium uranyl tricarbonate. All animals died five days after the onset of the experiment due to renal failure. Slightly soluble compounds, ammonium diuranate and uranyl acetate, caused only a slight decrease in body weight. Uranium dioxide, the most insoluble compound used, induced only a transitory slight body weight decrease. Histopathological study revealed damages to the tissues of topicated skin, hair follicles and adnexal glands. High concentration of uranium was indicated in bone, teeth and kidneys by X-ray scanning

  5. Thermogravimetric control of intermediate compounds in uranium metallurgy

    International Nuclear Information System (INIS)

    Gasco Sanchez, L.; Fernandez Cellini, R.

    1959-01-01

    The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs

  6. Redox behaviour of uranium with iron compounds

    International Nuclear Information System (INIS)

    Ithurbide, A.

    2009-10-01

    An option investigated for the management of long-term nuclear waste is a repository in deep geological formations. It is generally admitted that the release of radionuclides from the spent fuel in the geosphere could occur several thousand years after the beginning of the storage. Therefore, to assess the safety of the long-term disposal, it is important to consider the phenomena that can reduce the migration, and in particular the migration of uranium. The aim of this work is to study if siderite, an iron compound present both in the near - and far -field, can limit this migration as well as the role played by the redox process. Siderite thin layers have been obtained by electrochemistry. The layers are adherent and homogeneous. Their thickness is about 1 μm and they are composed of spherical grains. Analytical characterizations performed show that siderite is free of any impurity and does not exhibit any trace of oxidation. The interactions between siderite and uranium (VI) have been carried out in solutions considered as representative of environmental waters, in terms of pH and carbonate concentration. The retention of uranium on the thin layer is important since, after 24 hours of interaction, it corresponds to retention capacities of several hundreds of uranium micro-moles per gram of siderite. XPS analysis show that, in any studied condition, part of uranium present on the thin layer is reduced into an over stoichiometric uranium dioxide. The process of interaction differs depending on the considered environment, specially on the stability of siderite. (author)

  7. Carbon determination in uranium and its compounds

    International Nuclear Information System (INIS)

    Silva Queiroz, C.A. da; Abrao, A.

    1982-01-01

    Carbon content in uranium and its compounds, especially ceramic grade UO 2 , must be controlled rigorously. A method for the determination of carbon with the aid of commercial equipment which uses platinum as a catalyst for the oxidation of CO, and infrared cells for CO 2 measurement is described. The detection limit is 5μg C/g U and the determination range is 0.0005 to 5% C/U. The method is being used routinely to control the carbon content in nuclear fuel materials. (Author) [pt

  8. Study on growth of highly pure uranium compounds

    International Nuclear Information System (INIS)

    Shikama, Tatsuo; Ochiai, Akira; Suzuki, Kenji.

    1992-01-01

    We developed the systems for growing highly pure uranium compounds to study their intrinsic physical properties. Uranium metal was zone refined under low contamination conditions as far as possible. Chemical analysis of the purified uranium was performed using the inductive coupled plasma emission spectrometry (ICP). The problem that emission spectra of the uranium conceal those of analyzed impurities was settled by extraction of the uranium using tri-n-butyl-phosphate (TBP). The result shows that some metallic impurities such as Pb, Mn, Cu etc. evaporated by the r.f. heating and other usual metallic impurities moved to the end of rod with molten zone. Therefore, we conclude that the zone refining technique is much effective to the removal of metallic impurities and we obtained highly purified uranium metal of 99.99 % up with regard to metallic impurities. Using the purified uranium, we attempted to grow a highly pure uranium-titanium single crystals. (author)

  9. New uranium compounds preparation and use as catalyst for hydrogenation of non-saturated organic compounds

    International Nuclear Information System (INIS)

    Arnaudet, L.; Folcher, G.

    1985-01-01

    Preparation of new organic uranium compounds and their use as catalysts for hydrogenation of non-saturated organic compounds are described. These compounds include Uranium III, a cyclopentadienic group, an alkyl group and an acetylenic derivative C 6 H 5 C triple bonds CR fixed by a π bond. Catalysts can be prepared with depleted uanium for hydrogenation of olefins for example [fr

  10. Determination of chlorine in nuclear-grade uranium compounds

    International Nuclear Information System (INIS)

    Yang Chunqing; Liu Fuyun; Huang Dianfan

    1988-01-01

    The determination of chlorine in nuclear-grade uranium compounds is discribed. Chlorine is separated from uranium oxide pyrohydrolytically with stream of wet oxygen in a furnace at 800 ∼ 900 deg C. Chlorine is volatilized as hydrochloric acid, absorbed in a dilute alkaline solution and measured with chlorine-selective electrode. This method covers the concentration range of 10 ∼ 500 pm chlorine in uranium oxide. Precision of at least ± 10% and recovery of 85 ∼ 108% have been reported

  11. Analysis of uranium and its compounds. Ruthenium spectrographic determination

    International Nuclear Information System (INIS)

    Anon.

    Ruthenium determination in uranium and its compounds, suitable for content greater than 0.1 ppm with respect to uranium, by dissolution in sulfuric acid and addition of palladium as an internal standard, separation of the precipitated ruthenium, in the presence of gold, by reduction with zinc, the precipitate is calcined and ruthenium is determined by spectrography [fr

  12. Low molecular weight compounds as effective dispersing agents in the formation of colloidal silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Natsuki, Jun; Natsuki, Toshiaki, E-mail: natsuki@shinshu-u.ac.jp; Abe, Takao [Shinshu University, Faculty of Textile Science and Technology (Japan)

    2013-03-15

    A convenient method to synthesize uniform, well-dispersed colloidal silver nanoparticles is described. Aldonic acid or {alpha}-hydroxy acid compounds of low molecular weight are used instead of polymeric compounds as dispersing agents to prepare silver nanoparticles. The size, conformation, and electrical conductivity of the silver nanoparticles, and the effect and function of the dispersing agents are investigated in detail. Using these low molecular weight compounds as dispersing agents, silver nanoparticles with a diameter of 10 nm or less and high electrical conductivity can be obtained. In addition, this procedure allows silver nanoparticles to be sintered at 150 Degree-Sign C, which is lower than that required for silver nanoparticle formulation using polymeric compounds (200 Degree-Sign C). The silver nanoparticles produced by this process can be used to prepare various inks and to manufacture electronic circuits. It is found that low molecular weight compounds are more effective dispersing agents than polymeric compounds in the formation of silver nanoparticles.

  13. Uranium

    International Nuclear Information System (INIS)

    Hamdoun, N.A.

    2007-01-01

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

  14. Physicochemical aspects of extraction of uranium concentrate from the wastes and thermodynamic characteristics of thorium-uranium compounds

    International Nuclear Information System (INIS)

    Khamidov, F.A.

    2017-01-01

    The purpose of present work is elaboration of physicochemical aspects of extraction of uranium concentrate from the wastes and study of thermodynamic characteristics of thorium-uranium compounds. Therefore, the radiological monitoring of tailing dumps of Tajikistan has been conducted; the obtaining of uranium concentrate from the tailing dumps of uranium production has been studied; the obtaining of uranium concentrate from the tailing dumps of uranium production with application of local sorbents has been studied as well; thermal stability and thermodynamic characteristics of uranium-thorium compounds has been investigated; the flowsheets of extraction of uranium concentrate from the wastes have been elaborated.

  15. Contribution to study of effects consecutive to alpha decay of uranium 238 in some uranium compounds and uranium ores

    International Nuclear Information System (INIS)

    Ordonez-Regil, E.

    1985-06-01

    The consequences of alpha decay of 238 U in uranium compounds and in uranium bearing ores have been examined in two ways: leaching of 234 Th and determination of the activity ratio of 234 U and 238 U. The results have been interpreted mainly in terms of the ''hot'' character of the nascent 234 Th atoms [fr

  16. French experience with Uranium compounds: conclusions of medical working group

    International Nuclear Information System (INIS)

    Berard, P.; Mazeyrat, C.; Auriol, B.; Montegue, A.; Estrabaud, M.; Grappin, L.; Giraud, J.M.

    2002-01-01

    The authors who represent several organisations and industrial firms, present observations conducted for some thirty years in France, including routine monitoring or special measurements following contamination by uranium compounds. They propose recommendations for radio toxicological monitoring of workers exposed to industrial uranium compounds and they comment on urine and faecal collections in relation to specific exposures. Our working group, set up by the CEA Medical Adviser in 1975, consists of French specialists in uranium radio toxicology. Their role is to propose recommendations for the monitoring of working conditions and exposed workers. The different plants process chemically and metallurgically, and machine large quantities of uranium with various 235U enrichments. Radio toxicological monitoring of workers exposed to uranium compounds requires examinations prescribed according to the kind of product manipulated and the industrial risk of the workplace. The range of examinations that are useful for this kind of monitoring includes lung monitoring, urine analyses and faecal sampling. The authors present the frequency of the monitoring for routine or special conditions according to industrial exposure, time and duration of collection of excreta (urine and faeces), the necessity of a work break, precautions for preservation of the samples and the ways in interpreting excretion analysis according to natural food intakes

  17. Metabolism and toxicology of the uranium compounds

    International Nuclear Information System (INIS)

    Salomon, A.P.

    1976-01-01

    Three important points to be considered in the metabolic behaviour of uranium are: 1) ionic behaviour which depends only on its chemical characteristics; 2) behaves in the organism as a unique element and has no metabolism similar to others like for example Sr-90 and Ba-140 which are akin to Ca; and 3) metabolism is identical for the three isotopes of uranium and has no isotopic effect. The metabolic decomposition undergoes three phases namely: 1) absorption of the components up to the blood streams; 2) distribution through the blood into the organs; and 3) elimination. The mode of entry in the organism is through inhalation, ingestion, wounds, absorption through the skin, and entry by the eyes. Uranium decomposes in the blood after its entry, disperses in the extracellular medium and deposits in the different organs of the body. However, it has no definite fixation and the different compartments are always in equilibrium with each other. Elimination of contamination is through the feces and urine. In case of massive absorption, that is either acute or sub-acute toxicity, the following are the subsequent effects: a) clinical effects major lesion in the kidneys whatever the mode of entry may be and feebleness of the muscles, apathy and nausea are noted; b) lesions in the renal region-yellowish gray in the medular and critical region; c) biological effects-appearance of proteinuria and catalysuria, cellular wastes in the urine and a change in the capacity to reabsorb Na + , Cl - , and glucose. The lethal dose is 1 mg U-nat/kg.wt. The dose provoking renal lesion is 0.1mg U/kg.wt. The maximum permissible dose is: a) annual dose 40 mg U-nat/yr; b) Inhalation 2.5 mg/day; c) Ingestion 150 mg/2 days consecutive (soluble = 4.7x10 -1 μCi, insoluble = 3.4x10 -2 μCi

  18. Assessing the Renal Toxicity of Capstone Depleted Uranium Oxides and Other Uranium Compounds

    International Nuclear Information System (INIS)

    Roszell, Laurie E.; Hahn, Fletcher; Lee, Robyn B.; Parkhurst, MaryAnn

    2009-01-01

    The primary target for uranium toxicity is the kidney. The most frequently used guideline for uranium kidney burdens is the International Commission on Radiation Protection (ICRP) value of 3 (micro)g U/g kidney, a value that is based largely upon chronic studies in animals. In the present effort, we have developed a risk model equation to assess potential outcomes of acute uranium exposure. Twenty-seven previously published case studies in which workers were acutely exposed to soluble compounds of uranium (as a result of workplace accidents) were analyzed. Kidney burdens of uranium for these individuals were determined based on uranium in the urine, and correlated with health effects observed over a period of up to 38 years. Based upon the severity of health effects, each individual was assigned a score (- to +++) and then placed into an Effect Group. A discriminant analysis was used to build a model equation to predict the Effect Group based on the amount of uranium in the kidneys. The model equation was able to predict the Effect Group with 85% accuracy. The risk model was used to predict the Effect Group for Soldiers exposed to DU as a result of friendly fire incidents during the 1991 Gulf War. This model equation can also be used to predict the Effect Group of new cases in which acute exposures to uranium have occurred

  19. Lattice anisotropy in uranium ternary compounds

    DEFF Research Database (Denmark)

    Maskova, S.; Adamska, A.M.; Havela, L.

    2012-01-01

    Several U-based intermetallic compounds (UCoGe, UNiGe with the TiNiSi structure type and UNiAl with the ZrNiAl structure type) and their hydrides were studied from the point of view of compressibility and thermal expansion. Confronted with existing data for the compounds with the ZrNiAl structure...

  20. Simulation of uranium and plutonium oxides compounds obtained in plasma

    Science.gov (United States)

    Novoselov, Ivan Yu.; Karengin, Alexander G.; Babaev, Renat G.

    2018-03-01

    The aim of this paper is to carry out thermodynamic simulation of mixed plutonium and uranium oxides compounds obtained after plasma treatment of plutonium and uranium nitrates and to determine optimal water-salt-organic mixture composition as well as conditions for their plasma treatment (temperature, air mass fraction). Authors conclude that it needs to complete the treatment of nitric solutions in form of water-salt-organic mixtures to guarantee energy saving obtainment of oxide compounds for mixed-oxide fuel and explain the choice of chemical composition of water-salt-organic mixture. It has been confirmed that temperature of 1200 °C is optimal to practice the process. Authors have demonstrated that condensed products after plasma treatment of water-salt-organic mixture contains targeted products (uranium and plutonium oxides) and gaseous products are environmental friendly. In conclusion basic operational modes for practicing the process are showed.

  1. Determination of oxygen in uranium compounds using sulfur monochloride

    International Nuclear Information System (INIS)

    Baudin, G.; Besson, J.; Blum, P.L.; Tran-Van, Danh

    1964-01-01

    The authors have described in an other paper (Anal. Chim. Acta, in press) a method for oxygen determination in uranium compounds, in which the sample is attacked by sulfur monochloride. The present paper is concerned with the experimental aspects of the method: apparatus procedure. (authors) [fr

  2. Limits for the release of uranium compounds to the environment

    International Nuclear Information System (INIS)

    Lopez, F.; Ferruz, P.; Aguayo, A.

    1987-01-01

    A conservative criteria to be be followed by a Regulatory Body, in order to provide the limits of radioactive material release in the environment, When all the parameters are not available for the optimization of radiation protection is presented. This criteria can be applied to stablishment of radioactive release limits for uranium compounds from the nuclear fuel cycle facilities. (author)

  3. Precise coulometric titration of uranium in a high-purity uranium metal and in uranium compounds

    International Nuclear Information System (INIS)

    Tanaka, Tatsuhiko; Yoshimori, Takayoshi

    1975-01-01

    Uranium in uranyl nitrate, uranium trioxide and a high-purity uranium metal was assayed by the coulometric titration with biamperometric end-point detection. Uranium (VI) was reduced to uranium (IV) by solid bismuth amalgam in 5M sulfuric acid solution. The reduced uranium was reoxidized to uranium (VI) with a large excess of ferric ion at a room temperature, and the ferrous ion produced was titrated with the electrogenerated manganese(III) fluoride. In the analyses of uranium nitrate and uranium trioxide, the results were precise enough when the error from uncertainty in water content in the samples was considered. The standard sample of pure uranium metal (JAERI-U4) was assayed by the proposed method. The sample was cut into small chips of about 0.2g. Oxides on the metal surface were removed by the procedure shown by National Bureau of Standards just before weighing. The mean assay value of eleven determinations corrected for 3ppm of iron was (99.998+-0.012) % (the 95% confidence interval for the mean), with a standard deviation of 0.018%. The proposed coulometric method is simple and permits accurate and precise determination of uranium which is matrix constituent in a sample. (auth.)

  4. Tris(bis(trimethylsilyl)amido)uranium: Compounds with tri-, tetra-, and penta-valent uranium

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, J.L.

    1988-04-01

    This trivalent uranium compound, serves as a precursor to new tri-, tetra-, and penta-valent uranium species. The geometry about the U atom is pyramidal. Lewis-base coordination compounds of U(N(SiMe/sub 3/)/sub 2/)/sub 3/ with a one-to-one- ratio of Lewis base to uranium were isolated with pyridine, 4-dimethylamino-pyridine, 2,6-Me/sub 2/-C/sub 6/H/sub 3/NC, and TPO. Two-to-one coordination compounds were obtained with t-butylnitrile and t-butylisocyanide. Compounds with more sterically demanding bases could not be isolated. The expected decrease in U-N(SiMe/sub 3/)/sub 2/ bond length with increase in oxidation state is not observed. Reaction of ClU(N(SiMe/sub 3/)/sub 2/)/sub 3/and Li(NH(p-tolyl)) yields the uranium (IV) dimer, U/sub 2/(N(SiMe/sub 3/)/sub 2/)/sub 4/(..mu..-N(p-tolyl))/sub 2/. Reaction with 2,4,6-triemethylaniline produces a dimer. Analogous substitution products could not be obtained with aniline or p-toluidine. t-Bu/sub 3/CO/sup /minus//, t-Bu/sub 2/CHO/sup /minus//, and t-Bu/sub 3/SiO/sup /minus// are used to synthesize new tetravalent, mononuclear uranium compounds. Reaction of ClU(tritox)/sub 3/ with alkyllithium reagents leads to isolation of RU(tritox)/sub 3/. The reaction of U(ditox)/sub 4/ with MeLi affords the addition product U(ditox)/sub 4/(Me)Li, whose crystal structure is described. Preparation of uranium silox compounds is reported. 97 refs., 26 figs., 39 tabs.

  5. Tris[bis(trimethylsilyl)amido]uranium: Compounds with tri-, tetra-, and penta-valent uranium

    International Nuclear Information System (INIS)

    Stewart, J.L.

    1988-04-01

    This trivalent uranium compound, serves as a precursor to new tri-, tetra-, and penta-valent uranium species. The geometry about the U atom is pyramidal. Lewis-base coordination compounds of U[N(SiMe 3 ) 2 ] 3 with a one-to-one- ratio of Lewis base to uranium were isolated with pyridine, 4-dimethylamino-pyridine, 2,6-Me 2 -C 6 H 3 NC, and TPO. Two-to-one coordination compounds were obtained with t-butylnitrile and t-butylisocyanide. Compounds with more sterically demanding bases could not be isolated. The expected decrease in U-N(SiMe 3 ) 2 bond length with increase in oxidation state is not observed. Reaction of ClU[N(SiMe 3 ) 2 ] 3 and Li[NH(p-tolyl)] yields the uranium (IV) dimer, U 2 [N(SiMe 3 ) 2 ] 4 [μ-N(p-tolyl)] 2 . Reaction with 2,4,6-triemethylaniline produces a dimer. Analogous substitution products could not be obtained with aniline or p-toluidine. t-Bu 3 CO/sup /minus//, t-Bu 2 CHO/sup /minus//, and t-Bu 3 SiO/sup /minus// are used to synthesize new tetravalent, mononuclear uranium compounds. Reaction of ClU(tritox) 3 with alkyllithium reagents leads to isolation of RU(tritox) 3 . The reaction of U(ditox) 4 with MeLi affords the addition product U(ditox) 4 (Me)Li, whose crystal structure is described. Preparation of uranium silox compounds is reported. 97 refs., 26 figs., 39 tabs

  6. Feasibility study of the dissolution rates of uranium ore dust, uranium concentrates and uranium compounds in simulated lung fluid

    International Nuclear Information System (INIS)

    Robertson, R.

    1986-01-01

    A flow-through apparatus has been devised to study the dissolution in simulated lung fluid of aerosol materials associated with the Canadian uranium industry. The apparatus has been experimentally applied over 16 day extraction periods to approximately 2g samples of < 38um and 53-75um particle-size fractions of both Elliot Lake and Mid-Western uranium ores. The extraction of uranium-238 was in the range 24-60% for these samples. The corresponding range for radium-226 was 8-26%. Thorium-230, lead-210, polonium-210, and thorium-232 were not significantly extracted. It was incidentally found that the elemental composition of the ores studied varies significantly with particle size, the radionuclide-containing minerals and several extractable stable elements being concentrated in the smaller size fraction. Samples of the refined compounds uranium dioxide and uranium trioxide were submitted to similar 16 day extraction experiments. Approximately 0.5% of the uranium was extracted from a 0.258g sample of unsintered (fluid bed) uranium dioxide of particle size < 38um. The corresponding figure for a 0.292g sample of uranium trioxide was 97%. Two aerosol samples on filters were also studied. Of the 88ug uranium initially measured on stage 2 of a cascade impactor sample collected from the yellow cake packing area of an Elliot Lake mill, essentially 100% was extracted over a 16 day period. The corresponding figure for an open face filter sample collected in a fuel fabrication plant and initially measured at 288ug uranium was approximately 3%. Recommendations are made with regard to further work of a research nature which would be useful in this area. Recommendations are also made on sampling methods, analytical methods and extraction conditions for various aerosols of interest which are to be studied in a work of broader scope designed to yield meaningful data in connection with lung dosimetry calculations

  7. Poly thiophene hydrophobic and hydrophilic compounds, silver and iodine synthesized by plasma

    International Nuclear Information System (INIS)

    Palacios, J.C.; Chavez, J.A.; Olayo, M.G.; Cruz, G.J.

    2007-01-01

    Compounds in thin films of poly thiophene with silver and poly thiophene doped with iodine and silver using splendor discharges were synthesized. It is studied the wettability of the compounds and its transport properties. It was found that the compounds can modify their hydrophilic to hydrophobic behavior controlling their surface ruggedness and the metallic content. The doped with iodine plays a fundamental paper in the modification of the ruggedness of the compounds. (Author)

  8. Photon attenuation properties of some thorium, uranium and plutonium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Singh, V. P.; Badiger, N. M. [Karnatak University, Department of Physics, Dharwad-580003, Karnataka (India); Vega C, H. R., E-mail: kudphyvps@rediffmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2015-10-15

    Mass attenuation coefficients, effective atomic numbers, effective electron densities for nuclear materials; thorium, uranium and plutonium compounds have been studied. The photon attenuation properties for the compounds have been investigated for partial photon interaction processes by photoelectric effect, Compton scattering and pair production. The values of these parameters have been found to change with photon energy and interaction process. The variations of mass attenuation coefficients, effective atomic number and electron density with energy are shown graphically. Moreover, results have shown that these compounds are better shielding and suggesting smaller dimensions. The study would be useful for applications of these materials for gamma ray shielding requirement. (Author)

  9. Lattice anisotropy in uranium ternary compounds: UTX

    International Nuclear Information System (INIS)

    Mašková, S.; Adamska, A.M.; Havela, L.; Kim-Ngan, N.-T.H.; Przewoźnik, J.; Daniš, S.; Kothapalli, K.; Kolomiets, A.V.; Heathman, S.; Nakotte, H.; Bordallo, H.

    2012-01-01

    Highlights: ► Compressibility and thermal expansion of several U-based compounds were established. ► The direction of the U–U bonds is the “soft” crystallographic direction. ► Highest coefficient of linear thermal expansion is in the direction of the U–U bonds. ► The closer the U atoms are together the better they can be compressed together. - Abstract: Several U-based intermetallic compounds (UCoGe, UNiGe with the TiNiSi structure type and UNiAl with the ZrNiAl structure type) and their hydrides were studied from the point of view of compressibility and thermal expansion. Confronted with existing data for the compounds with the ZrNiAl structure type a common pattern emerges. The direction of the U–U bonds with participation of the 5f states is distinctly the “soft” crystallographic direction, exhibiting also the highest coefficient of linear thermal expansion. The finding leads to an apparent paradox: the closer the U atoms are together in a particular direction the better they can be additionally compressed together by applied hydrostatic pressure.

  10. Disorder effects in strongly correlated uranium compounds

    International Nuclear Information System (INIS)

    Suellow, S.; Maple, M.B.; Tomuta, D.; Nieuwenhuys, G.J.; Menovsky, A.A.; Mydosh, J.A.; Chau, R.

    2001-01-01

    Moderate levels of crystallographic disorder can dramatically affect the ground-state properties of heavy fermion compounds. In particular, the role of disorder close to a quantum critical point has been investigated in detail. However, crystallographic disorder is equally effective in altering the properties of magnetically ordered heavy fermion compounds like URh 2 Ge 2 , where disorder-induced spin-glass behavior has been observed. In this system, moreover, the magnetic ground state can be tuned from a spin-glass to a long-range ordered antiferromagnetic one by means of an annealing treatment. The transformation of the magnetic state is accompanied by a transition in the transport properties from 'quasi-insulating' (dρ/dT 2 Ge 2 will be discussed. Of particular interest is the resistivity of as-grown URh 2 Ge 2 , which resembles the Non-Fermi-liquid system UCu 4 Pd, suggesting that a common mechanism - the crystallographic disorder - controls the transport properties of these materials

  11. Synthesis and studies of some organometallic compounds of uranium IV

    International Nuclear Information System (INIS)

    Marquet-Ellis, Hubert; Folcher, Gerard.

    1975-06-01

    The organometallic compounds of uranium IV have been well known for a long-time but some difficulties in the synthese subsist. The procedures and the apparatus allowing to obtain these compounds with good yields are described. The cyclopenta dienyl compounds U(C 5 H 5 ) 3 Cl, U(C 5 H 5 ) 4 are prepared by reaction of UCl 4 with Na(C 5 H 5 ) in tetrahydrofurane. The cyclooctatetraene compound U(C 8 H 8 ) 2 ''Uranocene'' is obtained by reaction of K 2 (C 8 H 8 ) on UCl 4 in tetrahydrofurane. The NMR spectrum of the solution during the reaction shows the appearance of the product. These compounds have been identified by chemical analysis and X rays. The visible spectra of U(C 5 H 5 ) 2 Cl and U(C 8 H 8 ) 2 in gaseous phase have been obtained [fr

  12. Post-process intensification of photographic silver images, using radioactive compounds

    International Nuclear Information System (INIS)

    1979-01-01

    A method of post-process intensification of silver images on a developed and fixed photographic film or plate is described, comprising the steps of (a) converting silver of the developed film or plate to a radioactive compound by contracting the film or plate with an aqueous alkaline solution of an organo-S 35 compound which reacts selectively with silver in a photographic film or plate; (b) placing the film or plate treated in step (a) in direct contact with a receiver film which is sensitive to beta radiation whereby the receiver film is exposed by radiation from the radioactive compound; and (c) developing and fixing the resulting intensified receiver film. (author)

  13. Polynuclear compounds of uranium: structure, reactivity and properties

    International Nuclear Information System (INIS)

    Mougel, V.

    2012-01-01

    The study and comprehension of actinide's fundamental chemistry have important implications both for the development of new nuclear fuel and for the nuclear fuel reprocessing. One of the major issues in these processes is the ease of uranium to undergo redox reactions and to form polynuclear assemblies, which largely perturb these processes. However, despite their relevance, only few synthetic routes towards polynuclear uranium assemblies are described in the literature, and most of the polynuclear complexes reported are formed by serendipity rather than by rational design. Moreover, polynuclear uranium compounds are highly promising for the design of magnetic materials with improved properties and for reactivity studies. The aim of this work is the synthesis of polynuclear uranium complexes and the study of their reactivity and coordination properties. New synthetic routes to uranium polynuclear assemblies were developed and the study of their physico-chemical properties was carried out. The first approach investigated was based on pentavalent uranyl chemistry. Uranyl(V) is known to form aggregates via an interaction between uranyl moieties often named cation-cation interaction, but the isolation of uranyl(V) complexes had been largely limited by its ease of disproportionation. We isolated the first stable uranyl(V) polynuclear assembly using Salen-type Schiff base ligand. Based on this result, a fine tuning of the ligand and counter-ion properties resulted in the isolation of a large family of uranyl(V) polynuclear assemblies and in a better understanding of the parameters ruling their stability. Moreover, rare examples of clear antiferromagnetic couplings were observed with these complexes. In addition, this synthetic path was used to build the first 5f-3d cluster presenting single molecule magnet properties. The second approach used in this thesis consisted in the synthesis of oxo/hydroxo uranium clusters. The controlled hydrolysis of trivalent uranium in

  14. Methodology for uranium compounds characterization applied to biomedical monitoring

    International Nuclear Information System (INIS)

    Ansoborlo, E.; Chalabreysse, J.; Henge-Napoli, M.H.; Pujol, E.

    1991-01-01

    Chronic exposure and accidental contamination to uranium compounds in the nuclear industry, led the authors to develop a methodology in order to characterize those compounds applied to biomedical monitoring. Such a methodology, based on the recommendation of the ICRP and the assessment of Annual Limit on Intake (ALI) values, involves two main steps: (1) The characterization of the industrial compound, i.e. its physico-chemical properties like density (g cm -3 ), specific area (m 2 g -1 ), x-ray spectrum (crystalline form), solid infrared spectrum (wavelength and bounds), mass spectrometry (isotopic composition), and particle size distribution including measurement of the Activity Median Aerodynamic Diameter (AMAD). They'll specially study aging and hydration state of some compounds. (2) The study of in vitro solubility in several biochemical medium like bicarbonates, Basal Medium Eagle (BME) used in cellular culture, Gamble solvent, which is a serum simulant, with oxygen bubbling, and Gamble added with superoxide anions O2 - . Those different mediums allow one to understand the dissolution mechanisms (oxidation, chelating effects...) and to give ICRP classification D, W, or Y. Those two steps are essential to assess a biomedical monitoring either in routine or accidental exposure, and to calculate the ALI. Results on UO3, UF4 and U02 in the French uranium industry are given

  15. Vibrational spectroscopy and structural analysis of complex uranium compounds (review)

    International Nuclear Information System (INIS)

    Umreiko, D.S.; Nikanovich, M.V.

    1985-01-01

    The paper reports on the combined application of experimental and theoretical methods of vibrational spectroscopy together with low-temperature luminescence data to determine the characteristic features of the formation and structure of complex systems, not only containing ligands directly coordinated to the CA uranium, but also associated with the extraspherical polyatomic electrically charged particles: organic cations. These include uranyl complexes and heterocyclical amines. Studied here were compounds of tetra-halouranylates with pyridine and its derivates, as well as dipyridyl, quinoline and phenanthroline. Structural schemes are also proposed for other uranyl complexes with protonated heterocyclical amines with a more complicated composition, which correctly reflect their spectroscopic properties

  16. Compound Nucleus Reactions in LENR, Analogy to Uranium Fission

    Science.gov (United States)

    Hora, Heinrich; Miley, George; Philberth, Karl

    2008-03-01

    The discovery of nuclear fission by Hahn and Strassmann was based on a very rare microanalytical result that could not initially indicate the very complicated details of this most important process. A similarity is discussed for the low energy nuclear reactions (LENRs) with analogies to the yield structure found in measurements of uranium fission. The LENR product distribution measured earlier in a reproducible way in experiments with thin film electrodes and a high density deuteron concentration in palladium has several striking similarities with the uranium fission fragment yield curve.ootnotetextG.H. Miley and J.A. Patterson, J. New Energy 1, 11 (1996); G.H. Miley et al, Proc ICCF6, p. 629 (1997).This comparison is specifically focussed to the Maruhn-Greiner local maximum of the distribution within the large-scale minimum when the fission nuclei are excited. Implications for uranium fission are discussed in comparison with LENR relative to the identification of fission a hypothetical compound nuclear reaction via a element ^306X126 with double magic numbers.

  17. Coordination compounds of titanium, zirconium, tin, thorium and uranium

    International Nuclear Information System (INIS)

    Deshpande, S.G.; Jain, S.C.

    1990-01-01

    Reactions of isatin, furoic acid and picolinic acid have been carried out with titanium tetrachloride, tin tetrachloride, thorium tetrachloride, zirconyl chloride and uranyl nitrate. While 2:3(metal:ligand) type compounds of isatin have been obtained with Ti(IV) and Sn(IV), zirconium(IV), thorium(IV), and uranium(VI) do not react with the ligand under similar experimental conditions. Furoic acid (FAH) and picolinic acid(PicH) form various chloro furoates and picolinates when reacted with TiCl 4 , ZrOCl 2 and ThCl 4 , but do not react with SnCl 4 . The various compounds synthesised have been characterised on the basis of elemental analysis, infrared studies, conductivity and thermogravimetric measurements. (author). 1 tab., 10 refs

  18. Use of an ion mobility spectrometer for detecting uranium compounds.

    Science.gov (United States)

    McLain, Derek R; Steeb, Jennifer L; Smith, Nicholas A

    2018-07-01

    The safeguards community currently lacks a method to rapidly determine the chemical form of radioactive and non-radioactive compounds in real time during inspection activities. Chemical speciation identification can provide important information on both the types of materials that are collected during environmental sampling and can inform inspectors as to where to focus efforts during inspections or complementary access visits. Ion Mobility Spectrometry (IMS) is an established field technique for the detection of explosives, narcotics, and other organic compounds. More recently, electrospray ionization (ESI) has been used to introduce inorganic compounds to IMS instruments for analysis. These techniques have shown the ability to supply chemical information on the compounds analyzed. Although these laboratory based instruments use a liquid-based injection system, there is evidence in the literature of unaltered and intact pharmaceutical tablets being volatilized and ionized in open atmosphere using heat and a Ni-63 source. This work determined that a commercial-off-the-shelf (COTS) IMS could be used for the identification of solid uranium compounds directly after sampling using a COTS sample swipe. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Molecular dynamics simulation of uranium compound adsorption on solid surface

    International Nuclear Information System (INIS)

    Omori, Yuki; Takizawa, Yuji; Okamoto, Tsuyoshi

    2010-01-01

    Particles mixed in the UF6 gas have the property of accumulating on the inside of piping or units. This type of accumulation will cause material unaccounted for (MUF) in the UF6 gas processing facilities. Development of a calculation model for estimating the accumulation rate of uranium compounds has been expected. And predicting possible part of the units where uranium compounds adsorb will contribute to design an effective detection system. The purpose of this study is to take the basic knowledge of the particle's adsorption mechanism from the microscopic point of view. In simulation analysis, UF5 model particle is produced, then two types of solid surfaces are prepared; one is a solid surface at rest and the other is a moving solid surface. The result obtained by the code 'PABS' showed that when the solid surface moves at a lower velocity, the particle's adsorption process dominates over the particle's breakup one. Besides the velocity of the solid surface, other principal factors affecting an adsorption ratio were also discussed. (author)

  20. Inactivation of the antibacterial and cytotoxic properties of silver ions by biologically relevant compounds.

    Directory of Open Access Journals (Sweden)

    Geraldine Mulley

    Full Text Available There has been a recent surge in the use of silver as an antimicrobial agent in a wide range of domestic and clinical products, intended to prevent or treat bacterial infections and reduce bacterial colonization of surfaces. It has been reported that the antibacterial and cytotoxic properties of silver are affected by the assay conditions, particularly the type of growth media used in vitro. The toxicity of Ag+ to bacterial cells is comparable to that of human cells. We demonstrate that biologically relevant compounds such as glutathione, cysteine and human blood components significantly reduce the toxicity of silver ions to clinically relevant pathogenic bacteria and primary human dermal fibroblasts (skin cells. Bacteria are able to grow normally in the presence of silver nitrate at >20-fold the minimum inhibitory concentration (MIC if Ag+ and thiols are added in a 1:1 ratio because the reaction of Ag+ with extracellular thiols prevents silver ions from interacting with cells. Extracellular thiols and human serum also significantly reduce the antimicrobial activity of silver wound dressings Aquacel-Ag (Convatec and Acticoat (Smith & Nephew to Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli in vitro. These results have important implications for the deployment of silver as an antimicrobial agent in environments exposed to biological tissue or secretions. Significant amounts of money and effort have been directed at the development of silver-coated medical devices (e.g. dressings, catheters, implants. We believe our findings are essential for the effective design and testing of antimicrobial silver coatings.

  1. Uranium magnetism in UGa2 and U(Gasub(1-x)Alsub(x))2 compounds

    International Nuclear Information System (INIS)

    Ballou, R.

    1983-01-01

    Magnetism of intermetallic compounds of uranium is studied. A monocrystal of the highly anisotropic ferromagnetic material UGa 2 is studied by polarized neutron diffraction. Localisation of 5f electrons is evidenced. Magnetic structure of uranium in UGa 2 is determined. The pseudobinary compound U(Gasub(1-x)Alsub(x)) 2 is studied for crystal structure, ferromagnetism, paramagnetism, specific heat and resistivity [fr

  2. Mortality (1968-2008) in a French cohort of uranium enrichment workers potentially exposed to rapidly soluble uranium compounds.

    Science.gov (United States)

    Zhivin, Sergey; Guseva Canu, Irina; Samson, Eric; Laurent, Olivier; Grellier, James; Collomb, Philippe; Zablotska, Lydia B; Laurier, Dominique

    2016-03-01

    Until recently, enrichment of uranium for civil and military purposes in France was carried out by gaseous diffusion using rapidly soluble uranium compounds. We analysed the relationship between exposure to soluble uranium compounds and exposure to external γ-radiation and mortality in a cohort of 4688 French uranium enrichment workers who were employed between 1964 and 2006. Data on individual annual exposure to radiological and non-radiological hazards were collected for workers of the AREVA NC, CEA and Eurodif uranium enrichment plants from job-exposure matrixes and external dosimetry records, differentiating between natural, enriched and depleted uranium. Cause-specific mortality was compared with the French general population via standardised mortality ratios (SMR), and was analysed via Poisson regression using log-linear and linear excess relative risk models. Over the period of follow-up, 131 161 person-years at risk were accrued and 21% of the subjects had died. A strong healthy worker effect was observed: all causes SMR=0.69, 95% CI 0.65 to 0.74. SMR for pleural cancer was significantly increased (2.3, 95% CI 1.06 to 4.4), but was only based on nine cases. Internal uranium and external γ-radiation exposures were not significantly associated with any cause of mortality. This is the first study of French uranium enrichment workers. Although limited in statistical power, further follow-up of this cohort, estimation of internal uranium doses and pooling with similar cohorts should elucidate potential risks associated with exposure to soluble uranium compounds. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  3. Silver nanoparticles are broad-spectrum bactericidal and virucidal compounds

    Directory of Open Access Journals (Sweden)

    Ixtepan-Turrent Liliana

    2011-08-01

    Full Text Available Abstract The advance in nanotechnology has enabled us to utilize particles in the size of the nanoscale. This has created new therapeutic horizons, and in the case of silver, the currently available data only reveals the surface of the potential benefits and the wide range of applications. Interactions between viral biomolecules and silver nanoparticles suggest that the use of nanosystems may contribute importantly for the enhancement of current prevention of infection and antiviral therapies. Recently, it has been suggested that silver nanoparticles (AgNPs bind with external membrane of lipid enveloped virus to prevent the infection. Nevertheless, the interaction of AgNPs with viruses is a largely unexplored field. AgNPs has been studied particularly on HIV where it was demonstrated the mechanism of antiviral action of the nanoparticles as well as the inhibition the transmission of HIV-1 infection in human cervix organ culture. This review discusses recent advances in the understanding of the biocidal mechanisms of action of silver Nanoparticles.

  4. Method of removing uranium and its compounds from mine wastewaters and from aqueous solutions discharged in hydrometallurgical uranium ore treatment

    International Nuclear Information System (INIS)

    Jilek, R.; Prochazka, H.; Kuhr, I.; Fuska, J.; Nemec, P.; Katzer, J.

    1974-01-01

    The separation of uranium and its compounds from mine wastewaters and from water solutions discharged from uranium ore hydrometallurgical treatment, and its eventual simultaneous concentration in the biomass during uranium ore technological processing are described. The solutions are replenished with nutrients necessary for the growth of microorganisms, mainly with nitrogen, carbon and phosphorus and inoculated with fungi. During submersion cultivation, uranium incorporates in the mycelium, or is bound physico-chemically to the mycelium components. Together with these components, uranium is mechanically separated, i.e., by filtration, centrifugation or sedimentation. Organisms of the Fungi imperfecti class, mainly the Aspergillus and Penicillium genera are used for cultivation which may be continuous or semicontinuous. (B.S.)

  5. Thermogravimetric control of intermediate compounds in uranium metallurgy; Control termogravimetrico de productos intermedios de la metalurgia del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Gasco Sanchez, L; Fernandez Cellini, R

    1959-07-01

    The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs.

  6. Thermogravimetric control of intermediate compounds in uranium metallurgy; Control termogravimetrico de productos intermedios de la metalurgia del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Gasco Sanchez, L.; Fernandez Cellini, R.

    1959-07-01

    The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs.

  7. Antibacterial, kinetics and bacteriolytic properties of silver(I) pyridinedicarboxylate compounds

    Energy Technology Data Exchange (ETDEWEB)

    Azócar, M. Ignacio, E-mail: manuel.azocar@usach.cl [Facultad de Química y Biología, Universidad de Santiago de Chile, Av. Bernardo O' Higgins 3363, Santiago (Chile); Gómez, Grace; Velásquez, Carla; Abarca, Romina [Facultad de Química y Biología, Universidad de Santiago de Chile, Av. Bernardo O' Higgins 3363, Santiago (Chile); Kogan, Marcelo J. [Departamento de Quimica Farmacologica y Toxicologica, Facultad de Ciencias Quimicas y Farmaceuticas, Universidad de Chile. Advanced Center for Chronic Diseases (ACCDiS) (Chile); Páez, Maritza [Facultad de Química y Biología, Universidad de Santiago de Chile, Av. Bernardo O' Higgins 3363, Santiago (Chile)

    2014-04-01

    Antibacterial properties of silver(I)-pyridinedicarboxylate compounds (with Pyridine-2,3-dicarboxylic(Lutidinic acid), pyridine-2,4-dicarboxylic (Quinolinic acid) and pyridine-2,5-dicarboxylic (Isocinchomeronic acid)) were studied against Escherichia coli, Listeria monocytogenes (ISP-65-08), Salmonella typhi and Staphylococcus aureus (ATCC 25923) using kinetics of grown inhibition, viability assays, minimum inhibitory concentration and optical microscopy. The 3 silver compounds were tested toward UV-radiation in order to characterize their light insensitivity for potential medical devices: UV-radiation curable polymers. Photophysical measurements show remarkable differences toward UV-radiation, which were explained based on their polymeric structures with multiple nature bonds between pyridinedicarboxylic ligands and Ag(I) centers. We found a bacteriolytic effect and differences in the antibacterial efficiency depending on the structure of the complexes and the nature of Ag-X (X = oxygen and nitrogen) bonds: AgQuinol > AgLutidin > AgIsocinchom. - Highlights: • Antibacterial efficiency of silver(I) complexes • Improving antimicrobial properties of silver(I) complexes • Insensitivity to air and UV light for medical devices • Broad-spectrum antibiotic ointment • Bacteriolytic mechanism of silver compounds.

  8. Semi-automatic version of the potentiometric titration method for characterization of uranium compounds.

    Science.gov (United States)

    Cristiano, Bárbara F G; Delgado, José Ubiratan; da Silva, José Wanderley S; de Barros, Pedro D; de Araújo, Radier M S; Dias, Fábio C; Lopes, Ricardo T

    2012-09-01

    The potentiometric titration method was used for characterization of uranium compounds to be applied in intercomparison programs. The method is applied with traceability assured using a potassium dichromate primary standard. A semi-automatic version was developed to reduce the analysis time and the operator variation. The standard uncertainty in determining the total concentration of uranium was around 0.01%, which is suitable for uranium characterization and compatible with those obtained by manual techniques. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Rare earths in uranium compounds and important evidences for nuclear forensic purposes

    International Nuclear Information System (INIS)

    Rosa, Daniele S.; Sarkis, Jorge E.S.

    2011-01-01

    Nuclear forensics mainly focuses on the nuclear or radioactive material and aims to providing indication on the intended use, the history and even the origin of the material. Uranium compounds have isotopic or chemical characteristics that provide unambiguous information concerning their origin and production process. Rare earths elements (REE) are a set of sixteen chemical elements in the periodic table, specifically the fourteen Lanthanides in addition scandium and yttrium. These elements are often found together but in widely variable concentrations in uncommon varieties of igneous rocks. A large amount of uranium is in rare earths deposits, and may be extracted as a by-product. Accordingly, REE in uranium compounds can be used as an evidence of uranium origin. In this study, REE was determined in uranium compounds from different origin. Measurements were carried out using a High resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) Element 2, in low resolution mode (R-300). (author)

  10. Identifying anthropogenic uranium compounds using soft X-ray near-edge absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Jesse D.; Bowden, Mark; Tom Resch, C.; Eiden, Gregory C.; Pemmaraju, C. D.; Prendergast, David; Duffin, Andrew M.

    2017-01-01

    Uranium ores mined for industrial use are typically acid-leached to produce yellowcake and then converted into uranium halides for enrichment and purification. These anthropogenic chemical forms of uranium are distinct from their mineral counterparts. The purpose of this study is to use soft X-ray absorption spectroscopy to characterize several common anthropogenic uranium compounds important to the nuclear fuel cycle. Non-destructive chemical analyses of these compounds is important for process and environmental monitoring and X-ray absorption techniques have several advantages in this regard, including element-specificity, chemical sensitivity, and high spectral resolution. Oxygen K-edge spectra were collected for uranyl nitrate, uranyl fluoride, and uranyl chloride, and fluorine K-edge spectra were collected for uranyl fluoride and uranium tetrafluoride. Interpretation of the data is aided by comparisons to calculated spectra. These compounds have unique spectral signatures that can be used to identify unknown samples.

  11. Dzyaloshinskii-Moriya interaction and magnetic anisotropies in Uranium compounds

    Science.gov (United States)

    Sandratskii, L. M.

    2018-05-01

    We report on the first-principles study of complex noncollinear magnetic structures in Uranium compounds. We contrast two cases. The first is the periodic magnetic structure of U2Pd2In with exactly orthogonal atomic moments, the second is an incommensurate plane spiral structure of UPtGe where the angle between atomic moments of nearest neighbors is also close to 90°. We demonstrate that the hierarchy of magnetic interactions leading to the formation of the magnetic structure is opposite in the two cases. In U2Pd2In, the magnetic anisotropy plays the leading role, followed by the Dzyaloshinskii-Moriya interaction (DMI) interaction specifying the chirality of the structure. Here, the interatomic exchange interaction does not play important role. In UPtGe the hierarchy of the interactions is opposite. The leading interaction is the interatomic exchange interaction responsible for the formation of the incommensurate spiral structure followed by the DMI responsible for the selected chirality of the helix. The magnetic anisotropy is very weak that is a prerequisite for keeping the distortion of the helical structure weak.

  12. Crystal growth of uranium compounds and study of UGe2

    International Nuclear Information System (INIS)

    Taufour, V.

    2011-01-01

    In this thesis, the study on the superconducting ferromagnet UGe 2 is presented. Crystal growth of UGe 2 single crystals was realized in a tetra-arc furnace using the Czochralski technique. This technique was also used to obtain high quality single crystals of other uranium compounds, notably UCoGe and URu 2 Si 2 . The Curie temperature of UGe 2 (T(Curie) = 53 K) decreases with pressure and is suppressed at p c = 1.5 GPa. Before being suppressed, the ferromagnetic transition changes from second to first order at a tricritical point. Precise resistivity and Hall resistivity measurements under pressure and magnetic field revealed the position of the tricritical point as well as its evolution under magnetic field which draw a wing structure phase diagram. Despite the theoretical prediction that this diagram is general for a ferromagnet, here we present the first experimental observation. Other measurements focus on the superconductivity (T sc = 0.75 K) which coexists with ferromagnetism under pressure. The bulk nature of the superconductivity is investigated by AC calorimetry measurements under pressure. The attention is turned to the interesting phenomenon of field enhanced superconductivity. (author) [fr

  13. Microporous Silico-Alumino Phosphate (SAPO) Compound For Uranium Sorption

    International Nuclear Information System (INIS)

    Siti-Amini

    1998-01-01

    The zeotype novel materials I.e. SAPO structures have been prepared to have particular property such as sorption or cations exchanger which can accommodate the uranyl ions. The SAPO's model was built from certain mole ratio of SiO 2 +AIO 2 +PO 2 using various template compounds of tetra(alkyl)s aminium hydroxide viz. Tetra-methyl, tetra-ethyl and tetra-propyl aminium. Those formed materials have been analyzed using x-ray diffraction spectrometer , then the data have been complied using the supporting software videozeo package Ver.3.1. The result have shown that crystalline structures of microporous SAPO materials formed are SAPO-20, SAPO-34, and SAPO-40. The exchanger capacities of some zeolites, SAPOs and ASP(1:3) have been studied and their selectivity to uranyl ions in acid solution (ph<3.5) has been determined by static isotherm exchanger process. The result have revealed various selectivity factors and occurrence of absorption mechanism in SAPO-n materials. This promises that uranium separation could be more effective using SAPO-n than that using other zeolites . The chloride ions have slightly decreased the ion-exchange capacity, while that of fluoride ions increased the ion-exchange capacity of ASP(1:3) for the uranyl ions

  14. Rays Emitted by Compounds of Uranium and of Thorium

    Indian Academy of Sciences (India)

    I examined a large number of metals, salts, oxides, and minerals [2]. The following table gives, for each substance, the magnitude of the current i in amperes (order of magnitude,. 10-11. ). The substances which I studied but omitted from the table are at least 100 times less active than uranium. Uranium containing some ...

  15. Determination of carbon in uranium and its compounds

    International Nuclear Information System (INIS)

    Perez-Garcia, M. M.

    1972-01-01

    This paper collects the analytical methods used our laboratories for the determination of carbon in uranium metal, uranate salts and the oxides, fluorides and carbides of uranium. The carbon is usually burned off in a induction or resistance oven under oxygen flow. The CO 2 is collected in barite solution. Where it is backtitrated with potassium biphthalate. (Author)

  16. Separation of chloride and fluoride from uranium compounds and their determination by ion selective electrodes

    International Nuclear Information System (INIS)

    Pires, M.A.F.; Abrao, A.

    1982-01-01

    Fluoride and chloride must be rigorously controlled in uranium compounds, especially in ceramic grade UO 2 . Their determination is very difficult without previous uranium separation, particularly when both are at a low concentration. A simple procedure is described for this separation using a strong cationic resin to retain the uranyl ion. Both anions are determined in the effluent solution. Uranium compounds of nuclear fuel cycle, especially ammonium diuranate, ammonium uranyl tricarbonate, sodium diuranate, uranium trioxide and dioxide and uranium peroxide are dissolved in nitric acid and the solutions are percolated through the resin column. Chloride and fluoride are determined in the effluent by selective electrodes, the detection limits being 0.02 μg F - /ml and 1.0 μg Cl - /ml. The dissolution of the sample, the acidity of the solution, the measurement conditions and the sensitivity of the method are discussed. (Author) [pt

  17. Soda-based glass fabricated from Thailand quartz sands doped with silver compound

    Science.gov (United States)

    Won-in, Krit; Dararutana, Pisutti

    2012-10-01

    Yellow colored glass which used for luxury art glass in ancient time was fabricated by the addition of silver compound into the molten glass. It was proved that it was actually silver nanoparticle technology. In this work, the SiO2-(Na2O,K2O)-CaO-B2O3-Al2O3-MgO glass system was prepared in the laboratory scale based on local quartz sands from Trat Province, eastern area of Thailand as the silica raw material. Various concentrations of silver nitrate were added. After the complete conventional melting process, the bubble-free yellow glasses were yielded. Physical and optical properties such as density, refractive index and optical absorption spectra were measured. Scanning electron microscope coupled with energy dispersive spectroscopy was carried out to study their morphology. The refractive indices and densities were increased as the increase of the silver contents. Electron micrographs showed the presence of silver nanoparticle in the glass matrix. UV-VIS spectra were in good agreement with that found from SEM measurements and corresponded with the universally accepted. It was also showed that the more brilliance on the surface of the glass products was obtained after firing with a gas torch.

  18. Large magnetoresistance in non-magnetic silver chalcogenides and new class of magnetoresistive compounds

    Science.gov (United States)

    Saboungi, Marie-Louis; Price, David C. L.; Rosenbaum, Thomas F.; Xu, Rong; Husmann, Anke

    2001-01-01

    The heavily-doped silver chalcogenides, Ag.sub.2+.delta. Se and Ag.sub.2+.delta. Te, show magnetoresistance effects on a scale comparable to the "colossal" magnetoresistance (CMR) compounds. Hall coefficient, magnetoconductivity, and hydrostatic pressure experiments establish that elements of narrow-gap semiconductor physics apply, but both the size of the effects at room temperature and the linear field dependence down to fields of a few Oersteds are surprising new features.

  19. Determination of 17 impurity elements in nuclear quality uranium compounds by atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    Andonie, O.; Smith, L.A.; Cornejo, S.

    1985-01-01

    A method is described for the determination of 17 elements (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, V and Zn) in the ppm level, in nuclearly pure uranium compounds by flame atomic absorption spectroscopy. The analysis is performed by first dissolving the uranium sample in nitric acid and then extracting the uranium with tributyl phosphate solution. The aqueous phase, free of uranium, which contains the elements to analyze is inspirated into the flame of an atomic absorption spectrophotometer using air-acetylene or nitrous oxide-acetylene flame according to the element in study. This method allows to extract the uranium selectively in more than 99.0% and the recovery of the elements sudied was larger 90% (for K) to 100% (for Cr). The sensitivity of the method vary from 0.096 μg/g U (for Cd) to 5.5 μg/g U (for Na). (Author)

  20. Recent progress of soft X-ray photoelectron spectroscopy studies of uranium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Fujimori, Shin-ichi; Takeda, Yukiharu; Okane, Tetsuo; Saitoh, Yuji [Condensed Matter Science Divisions, Japan Atomic Energy Agency, Sayo, Hyogo (Japan); Fujimori, Atsushi [Condensed Matter Science Divisions, Japan Atomic Energy Agency, Sayo, Hyogo (Japan); Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033 (Japan); Yamagami, Hiroshi [Condensed Matter Science Divisions, Japan Atomic Energy Agency, Sayo, Hyogo (Japan); Department of Physics, Faculty of Science, Kyoto Sangyo University, Kyoto 603-8555 (Japan); Yamamoto, Etsuji; Haga, Yoshinori [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Ōnuki, Yoshichika [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213 (Japan)

    2016-04-15

    Recent progresses in the soft X-ray photoelectron spectroscopy (PES) studies (hν ≳ 100 eV) for uranium compounds are briefly reviewed. The soft X-ray PES has enhanced sensitivities for the bulk U 5f electronic structure, which is essential to understand the unique physical properties of uranium compounds. In particular, the recent remarkable improvement in energy resolutions from an order of 1 eV to 100 meV made it possible to observe fine structures in U 5f density of states. Furthermore, soft X-ray ARPES becomes available due to the increase of photon flux at beamlines in third generation synchrotron radiation facilities.The technique made it possible to observe bulk band structures and Fermi surfaces of uranium compounds and therefore, the results can be directly compared with theoretical models such as band-structure calculations. The core-level spectra of uranium compounds show a systematic behavior depending on their electronic structures, suggesting that they can be utilized to determine basic physical parameters such as the U 5f-ligand hybridizations or Comlomb interaction between U 5f electrons. It is shown that soft X-ray PES provides unique opportunities to understand the electronic structures of uranium compounds.

  1. Dendrimer encapsulated Silver nanoparticles as novel catalysts for reduction of aromatic nitro compounds

    Science.gov (United States)

    Asharani, I. V.; Thirumalai, D.; Sivakumar, A.

    2017-11-01

    Polyethylene glycol (PEG) core dendrimer encapsulated silver nanoparticles (AgNPs) were synthesized through normal chemical reduction method, where dendrimer acts as reducing and stabilizing agent. The encapsulated AgNPs were well characterized using TEM, DLS and XPS techniques. The synthesized AgNPs showed excellent catalytic activity towards the reduction of aromatic nitro compounds with sodium borohydride as reducing agent and the results substantiate that dendrimer encapsulated AgNPs can be an effective catalyst for the substituted nitro aromatic reduction reactions. Also the kinetics of different nitro compounds reductions was studied and presented.

  2. The use of voltammetry for determining uranium and associated elements in compounds of nuclear interest

    International Nuclear Information System (INIS)

    Carvalho, F.M.S. de.

    1988-01-01

    The determination of uranium and some trace elements found as impurities in nuclear materials by the voltammetric technique using the hanging mercury drop electrode is presented. Emphasis is given to the determination of uranium, of major interest. Europium and ytterbium are simultaneously determined in fractions of individual lanthanides. A procedure for the simultaneous determination of copper, cadmium, nickel and zinc in water, industrial effluents and uranium compounds is discussed. The advantage of the procedure is its simplicity and easiness of execution, with excellent precision and accuracy. (author) [pt

  3. Flame photometric determination of Na, K and Li in uranium compounds

    International Nuclear Information System (INIS)

    Sabato, S.F.; Lordello, A.R.

    1985-01-01

    A flame photometric method for the determination of Na, K and Li in uranium compounds is described. The uranium is separated by solvent extraction from hydrochloric acid medium with tri-butyl phosphate. Amounts of uranium in order of 20 μg/ml don't cause any interference in the photometric results. The element Na presents a residual concentration due to the contamination of the reagents. The relative standard deviation is about 10% for the three elements. The relative error varies with the concentration of the element and it is between 1 and 24% for Na, between O and 12% for K and between O and 33% for Li. (Author) [pt

  4. Determination of chlorine in nuclear-grade uranium compounds by ion-selective electrode

    International Nuclear Information System (INIS)

    Yang Chunqing; Liu Fuyun; Huang Dianfan.

    1989-01-01

    The determination of microamount chlorine in nuclear-grade uranium compounds is described. Chlorine is separated from uranium oxide pyrohydrolytically with stream of wet oxygen in a furnace at 800-900 deg C. Chlorine is volatilized as hydrochloric acid, which then is absorbed in a dilute alkaline solution and measured with chlorine selective electrode. This method covers the concentration range of 10-500 ppm chlorine in uranium oxide. The relative standard diviation is better than 10% and recovery of 85-108% has been reported

  5. Synthesis of New Polyether Ether Ketone Derivatives with Silver Binding Site and Coordination Compounds of Their Monomers with Different Silver Salts

    Directory of Open Access Journals (Sweden)

    Jérôme Girard

    2016-05-01

    Full Text Available Polyether ether ketone (PEEK is a well-known polymer used for implants and devices, especially spinal ones. To overcome the biomaterial related infection risks, 4-4′-difluorobenzophenone, the famous PEEK monomer, was modified in order to introduce binding sites for silver ions, which are well known for their antimicrobial activity. The complexation of these new monomers with different silver salts was studied. Crystal structures of different intermediates were obtained with a linear coordination between two pyridine groups and the silver ions in all cases. The mechanical and thermal properties of different new polymers were characterized. The synthesized PEEKN5 polymers showed similar properties than the PEEK ones whereas the PEEKN7 polymers showed similar thermal properties but the mechanical properties are not as good as the ones of PEEK. To improve these properties, these polymers were complexed with silver nitrate in order to “cross-link” with silver ions. The presence of ionic silver in the polymer was then confirmed by thermogravimetric analysis (TGA and X-ray powder diffraction (XRPD. Finally, a silver-based antimicrobial compound was successfully coated on the surface of PEEKN5.

  6. Potential anticancer properties of bioactive compounds of Gymnema sylvestre and its biofunctionalized silver nanoparticles.

    Science.gov (United States)

    Arunachalam, Kantha Deivi; Arun, Lilly Baptista; Annamalai, Sathesh Kumar; Arunachalam, Aarrthy M

    2015-01-01

    Gymnema sylvestre is an ethno-pharmacologically important medicinal plant used in many polyherbal formulations for its potential health benefits. Silver nanoparticles (SNPs) were biofunctionalized using aqueous leaf extracts of G. sylvestre. The anticancer properties of the bioactive compounds and the biofunctionalized SNPs were compared using the HT29 human adenoma colon cancer cell line. The preliminary phytochemical screening for bioactive compounds from aqueous extracts revealed the presence of alkaloids, triterpenes, flavonoids, steroids, and saponins. Biofunctionalized SNPs were synthesized using silver nitrate and characterized by ultraviolet-visible spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, Fourier transform infrared spectroscopy, and X-ray diffraction for size and shape. The characterized biofunctionalized G. sylvestre were tested for its in vitro anticancer activity against HT29 human colon adenocarcinoma cells. The biofunctionlized G. sylvestre SNPs showed the surface plasmon resonance band at 430 nm. The scanning electron microscopy images showed the presence of spherical nanoparticles of various sizes, which were further determined using the Scherrer equation. In vitro cytotoxic activity of the biofunctionalized green-synthesized SNPs (GSNPs) indicated that the sensitivity of HT29 human colon adenocarcinoma cells for cytotoxic drugs is higher than that of Vero cell line for the same cytotoxic agents and also higher than the bioactive compound of the aqueous extract. Our results show that the anticancer properties of the bioactive compounds of G. sylvestre can be enhanced through biofunctionalizing the SNPs using the bioactive compounds present in the plant extract without compromising their medicinal properties.

  7. Silver nanoparticles embedded polymer sorbent for preconcentration of uranium from bio-aggressive aqueous media

    International Nuclear Information System (INIS)

    Das, Sadananda; Pandey, Ashok K.; Athawale, Anjali A.; Subramanian, M.; Seshagiri, T.K.; Khanna, Pawan K.; Manchanda, Vijay K.

    2011-01-01

    Adsorptive sorbent for bio-aggressive natural aqueous media like seawater was developed by one pot simultaneous synthesis of silver nanoparticles (Ag nps) and poly(ethylene glycol methacrylate phosphate) (PEGMP) by UV-initiator induced photo-polymerization. The photo-polymerization was carried out by irradiating N,N'-dimethylformamide (DMF) solution containing appropriate amounts of the functional monomer (ethylene glycol methacrylate phosphate), UV initiator (α,α'-dimethoxy-α-phenyl acetophenone), and Ag + ions with 365 nm UV light in a multilamps photoreactor. To increase mechanical strength, nano-composite sorbent (Ag-PEGMP) was also reinforced with thermally bonded non-woven poly(propylene) fibrous sheet. Transmission electron microscopy (TEM) of the nano-composite sorbent showed uniform distribution of spherical Ag nanoparticles with particles size ranging from 3 to 6 nm. The maximum amount of Ag 0 that could be anchored in the form of nanoparticles were 5 ± 1 and 10 ± 1 wt.% in self-supported PEGMP and poly(propylene) reinforced PEGMP matrices, respectively. Ag-PEGMP sorbent was found to be stable under ambient conditions for a period of six months. Ag-PEGMP composite sorbent did not exhibit growth at all after incubation with pre-grown Escherichia coli cells, and showed non-adherence of this bacteria to the composite. This indicated that composite sorbent has the bio-resistivity due to bacterial repulsion and bactericidal properties of Ag nanoparticles embedded in the PEGMP. Sorption of U(VI) in PEGMP and Ag-PEGMP nano-composite sorbents from well-stirred seawater was studied to explore the possibility of using it for uranium preconcentration from bio-aggressive aqueous streams. The nano-composite sorbent was used to preconcentrate U(VI) from a process aqueous waste stream.

  8. Separation of halogens from uranium compounds by means of pyrohydrolysis and their determination by ion chromatography

    International Nuclear Information System (INIS)

    Pires, M.A.F.; Brandao Filho, D.; Abrao, A.

    1987-07-01

    This paper describs the determination of fluorine in nuclear grade uranium compounds by means of phyrohydrolysis. A stream of wet oxygem at a temperature of 900 to 1000 0 C is passed through a quartz tube where the powdered samples is put. The halogens are volatilized as their respective acids that are absorbed in a buffer solution or water. The measurements are made with ion-seletive eletrodes or by ion chromatography. The sensitivity is of 1μg F - /g and 5μg Cl - /g. The separation of fluorine from uranium compounds by diferent methods is discussed. (Author) [pt

  9. Ion exchange separation of nitrate from uranium compounds and its determination by spectrophotometry and ion chromatography

    International Nuclear Information System (INIS)

    Pires, M.A.F.; Atalla, L.T.; Abrao, A.

    1985-11-01

    A procedure for the separation of nitrate from uranium compounds by retaintion of uranyl ion on a cationic ion exchanger and its determination in the effluent is described. Nitrate is analysed by the spectrometric method with 1-phenol-2,4-dissulphonic acid. This determination covers the 1 to 10 μg NO - 3 /mL range and requires an amount of 10 to 100 μg NO - 3 . The main interference is uranium (VI) due its own intense yellow color. This difficulty is overcome by the complete separation of UO 2 ++ with the cationic resin. Alternatively, the ion chromatography technique is used for the determination of nitrate in the effluent of the cationic resin. The determination was easily made by the comparison of the nitrate peak hights of the analyte and the standard solutions. The ion chromatography method is very sensitive (0,3 μg NO - 3 /mL), reproducible and suitable for routine analysis and permits the determination of fraction of part per million of nitrate in uranium. The results of nitrate determination using both spectrophotometric and ion chromatography techniques are compared. The method is being routinely applied for the quality control of uranium compounds in the fuel cycle, specially uranium oxide, ammonium diuranate, uranium peroxide and ammonium uranyl tricarbonate. (Author) [pt

  10. No fluorinated compounds in the uranium conversion process: risk analysis and proposition of pictograms

    International Nuclear Information System (INIS)

    Jeronimo, Adroaldo Clovis; Oliveira, Wagner dos Santos

    2012-01-01

    The plants comprising the chemical conversion of uranium, which are part of the nuclear fuel cycle, present some risks, among others, because are associated with the non-fluorinated compounds handled in these processes. This study is the analysis of the risks associated with these compounds, i e, the non-fluorinated reactants and products, handled in different chemical processing plants, which include the production of uranium hexafluoride, while emphasizing the responsibilities and actions that fit to the chemical engineer with regard to minimizing risks during the various stages. The work is based on the experience gained during the development and mastery of the technology of production of uranium hexafluoride, the IPEN/ CNEN-SP, during the '80s, with the support of COPESP -Navy of Brazil. (author)

  11. Study of the interactions between uranium and organic compounds in the hydrothermal systems

    International Nuclear Information System (INIS)

    Salze, David

    2008-01-01

    Formers studies on the relations between organic matter and uranium have shown that these interactions go since the complexation and the transport of uranium in organics fluids until its reduction by the organic matter leading to the uranium-bearing mineral precipitation. An experimental study of these reactions to 200 deg. C and 500 bars between experimental compounds (pure organic compounds) such as the n-alkanes (n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-dodecane, n-tetradecane and n-hexadecane), an n-alkene hydrocarbon (n-dec-1-ene), cycles (butyl-cyclohexane and cyclo-hexane) and the aromatic ones (butyl-benzene and naphthalene), and hexavalent uranium oxides was undertaken. These experiments allowed to show a progressive oxidation of n-alkanes starting from made up C6. The increasing size of the aliphatic chains and the increase in the time of setting in interaction are major factors of the increase in the environment oxidizing capacity in interaction with uranium on the organic compound. The determination of the oxidation step of uranium oxides after experiment made it possible to determine that in aqueous environment the aliphatic model compounds are reducers more powerful than the aromatic compounds. An organic matter from lake or marine origin generally has an aliphatic fraction larger than the organic matter of continental origin and thus will be more likely to reduce uranium. A natural example, the uranium deposits in the sandstones from Arlit, the tectono-lithologic type, was selected in order to apply the results obtained in the experimental part. They are located in fluviatile sandstones rich in organic matter of continental origin (type III) deposited in the paleo-channels. Former authors considered that only this organic matter of type III was responsible for the reduction of U (VI) in U (IV). Work which was undertaken in the present study shows that migrated oils of probable marine origin strongly contributed to the genesis

  12. Harnessing redox activity for the formation of uranium tris(imido) compounds

    Science.gov (United States)

    Anderson, Nickolas H.; Odoh, Samuel O.; Yao, Yiyi; Williams, Ursula J.; Schaefer, Brian A.; Kiernicki, John J.; Lewis, Andrew J.; Goshert, Mitchell D.; Fanwick, Phillip E.; Schelter, Eric J.; Walensky, Justin R.; Gagliardi, Laura; Bart, Suzanne C.

    2014-10-01

    Classically, late transition-metal organometallic compounds promote multielectron processes solely through the change in oxidation state of the metal centre. In contrast, uranium typically undergoes single-electron chemistry. However, using redox-active ligands can engage multielectron reactivity at this metal in analogy to transition metals. Here we show that a redox-flexible pyridine(diimine) ligand can stabilize a series of highly reduced uranium coordination complexes by storing one, two or three electrons in the ligand. These species reduce organoazides easily to form uranium-nitrogen multiple bonds with the release of dinitrogen. The extent of ligand reduction dictates the formation of uranium mono-, bis- and tris(imido) products. Spectroscopic and structural characterization of these compounds supports the idea that electrons are stored in the ligand framework and used in subsequent reactivity. Computational analyses of the uranium imido products probed their molecular and electronic structures, which facilitated a comparison between the bonding in the tris(imido) structure and its tris(oxo) analogue.

  13. Reaction of Tris(cyclopentadienyl)uranium compounds with amines, azides, and related ligands

    International Nuclear Information System (INIS)

    Rosen, R.K.

    1989-12-01

    The trivalent uranium compound, (MeC 5 H 4 ) 3 U(thf), serves as a one- or two-electron reducing agent towards azides, RN 3 . These reactions produce either the uranium(IV) azide, (MeC 5 H 4 ) 3 UN 3 , or uranium(V) imides, (MeC 5 H 4 ) 3 UNR. The role of steric and electronic effects upon this reaction has been investigated using several series of azides. For Me 3 XN 3 , the imides are produced when X = C or Si, both products are formed when X = Ge, and the azide is produced when X = Sn. For Ph 3 XN 3 , the azide is produced when X = C or Sn. For Ph 3-x CH 3 N 3 , the imide is produced when x = 2 and both compounds are produced when x = 1. For substituted phenylazides, RC 6 H 4 N 3 , only the imides are produced. The magnetic properties of uranium diimides, [(MeC 5 H 4 ) 3 U] 2 (μ-NRN), were investigated. Several uranium(III) amines, (MeC 5 H 4 ) 3 U(NH 2 R), were produced from (MeC 5 H 4 ) 3 U(thf) and RNH 2 , and NH 3 was found to be a better ligand towards (MeC 5 H 4 ) 3 U than is PMe 3

  14. Supercritical fluid extraction of uranium and thorium from nitric acid medium using organophosphorous compounds

    Energy Technology Data Exchange (ETDEWEB)

    Pitchaiah, K.C.; Sujatha, K.; Rao, C.V.S. Brahmmananda; Subramaniam, S.; Sivaraman, N.; Rao, P.R. Vasudeva [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Chemistry Group

    2015-06-01

    In recent years, Supercritical Fluid Extraction (SFE) technique has been widely used for the extraction of metal ions. In the present study, extraction of uranium from nitric acid medium was investigated using supercritical carbon dioxide (Sc-CO{sub 2}) containing various organophosphorous compounds such as trialkyl phosphates e.g. tri-iso-amyl phosphate (TiAP), tri-sec-butyl phosphate (TsBP) and tri-n-butyl phosphate (TBP), dialkylalkyl phosphonates, e.g. diamylamyl phosphonate (DAAP) and dibutyl butyl phosphonate (DBBP), dialkyl hydrogen phosphonates, e.g. dioctyl hydrogen phosphonate (DOHP), dioctylphosphineoxide (DOPO), trioctyl phosphine oxide (TOPO), n-octylphenyl N,N-diisobutyl carbamoylmethylphosphine oxide (CMPO) and di-2-ethyl-hexyl phosphoric acid (HDEHP). Some of these ligands have been investigated for the first time in the supercritical phase for the extraction of uranium. The extraction efficiency of uranium was studied with TiAP, DAAP and DBBP as a function of nitric acid concentration; the kinetics of the equilibration period (static extraction) and transportation of the metal complex (dynamic extraction) was investigated. The influence of pressure and temperature on the extraction behaviour of uranium with DAAP was studied from 4 N HNO{sub 3}. The extraction efficiency of uranium from 4 N nitric acid medium was found to increase in the order of phosphates < phosphonates < HDEHP < TOPO < CMPO. In the case of phosphates and phosphonates, the maximum extraction of uranium was found to be from 4 N HNO{sub 3} medium. The acidic extractants, HDEHP and DOHP showed relatively higher extraction at lower acidities. The relative extraction of uranium and thorium from their mixture was also examined using Sc-CO{sub 2} containing phosphates, phosphonates and TOPO. The ligand, TsBP provided better fractionation between uranium and thorium compared to trialkyl phosphates, dialkyl alkyl phosphonates and TOPO.

  15. Study of internal exposure to uranium compounds in fuel fabrication plants in Brazil

    International Nuclear Information System (INIS)

    Santos, Maristela Souza

    2006-01-01

    The International Commission on Radiological Protection (ICRP) Publication 66 and Supporting Guidance 3) strongly recommends that specific information on lung retention parameters should be used in preference to default values wherever appropriate, for the derivation of effective doses and for bioassay interpretation of monitoring data. A group of 81 workers exposed to UO 2 at the fuel fabrication facility in Brazil was selected to evaluate the committed effective dose. The workers were monitored for determination of uranium content in the urinary and faecal excretion. The contribution of intakes by ingestion and inhalation were assessed on the basis of the ratios of urinary to fecal excretion. For the selected workers it was concluded that inhalation dominated intake. According to ICRP 66, uranium oxide is classified as insoluble Type S compound. The ICRP Supporting Guidance 3 and some recent studies have recommended specific lung retention parameters to UO 2 . The solubility parameters of the uranium oxide compound handled by the workers at the fuel fabrication facility in Brazil was evaluated on the basis of the ratios of urinary to fecal excretion. Excretion data were corrected for dietary intakes. This paper will discuss the application of lung retention parameters recommended by the ICRP models to these data and also the dependence of the effective committed dose on the lung retention parameters. It will also discuss the problems in the interpretation of monitoring results, when the worker is exposed to several uranium compounds of different solubilities. (author)

  16. Method of semi-automatic high precision potentiometric titration for characterization of uranium compounds

    International Nuclear Information System (INIS)

    Cristiano, Barbara Fernandes G.; Dias, Fabio C.; Barros, Pedro D. de; Araujo, Radier Mario S. de; Delgado, Jose Ubiratan; Silva, Jose Wanderley S. da; Lopes, Ricardo T.

    2011-01-01

    The method of high precision potentiometric titration is widely used in the certification and characterization of uranium compounds. In order to reduce the analysis and diminish the influence if the annalist, a semi-automatic version of the method was developed at the safeguards laboratory of the CNEN-RJ, Brazil. The method was applied with traceability guaranteed by use of primary standard of potassium dichromate. The standard uncertainty combined in the determination of concentration of total uranium was of the order of 0.01%, which is better related to traditionally methods used by the nuclear installations which is of the order of 0.1%

  17. Contribution to the study of vacancies in silver and uranium (1962); Contribution a l'etude des lacunes dans l'argent et l'uranium (1962)

    Energy Technology Data Exchange (ETDEWEB)

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

    1961-12-15

    In metals, high temperature vacancies can be retained by quenching. Results are given for the quenching of uranium (in liquid helium) and of silver (in liquid nitrogen). In this last case the energy of formation (1.06 eV) and the energy of mobility (0.86 eV) of the vacancies have been measured as well as the energy of mobility of the divacancies (0.58 eV). If the quenching is slow, it is shown that it is possible to trap the vacancies on the impurities of the metal. This leads to increases in the electrical resistivity observed by annealing after quenching, the vacancies being released before disappearing into sinks. The vacancy-impurity binding energy (the impurity being probably oxygen which is present in the silver used at a concentration of 20 ppm. atom.) can thus be estimated to be 0.4 eV. (author) [French] Dans un metal, les lacunes de haute temperature peuvent etre retenues par trempe. On presente des experiences de trempe d'uranium (dans l'helium liquide) et d'argent (dans l'azote liquide). Dans ce dernier cas, on mesure l'energie de formation (1,06 eV) et l'energie de mobilite (0,86 eV) des lacunes ainsi que l'energie de mobilite des bilacunes (0,58 eV). Si la trempe est lente, on montre que l'on peut pieger des lacunes sur les impuretes du metal. On interprete de cette facon des augmentations de resistivite electrique observees par recuit apres trempe, les lacunes se depiegeant avant de disparaitre dans des puits. L'energie de liaison lacune-impurete (l'impurete etant probablement l'oxygene dont l'argent utilise contient 20 ppm. atom.) peut alors etre evalue 0,4 eV. (auteur)

  18. Review of experience gained in fabricating nuclear grade uranium and thorium compounds and their analytical quality control at the Instituto de Energia Atomica, Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Abrao, A.; Franca Junior, J.M.; Ikuta, A.

    1977-01-01

    The main activities developed at 'Instituto de Energia Atomica' Sao Paulo, Brazil, on the recovery of uranium from ores, the purification of uranium and thorium raw concentrates and their transformation in nuclear grade compounds, are reviewed. The design and assemble of pilot facilities for ammonium diuranate (ADV) uranium tetrafluoride, uranium trioxide, uranium oxide microspheres, uranyl nitrate denitration, uranim hexafluoride and thorium compounds are discussed. The establishment of analytical procedures are emphasized [pt

  19. Synthesis and properties of uranium compounds: pt.1

    International Nuclear Information System (INIS)

    Lee, C.W.; So, H.S.

    1982-01-01

    A guanidinium salt of [U(PW 11 O 39 ) 2 ]sup(10-), the solubility of which is adequate for crystal growing, has been synthesized. Using this salt or potassium salt, we have measured the stability of [U(PW 11 O 39 ) 2 ]sup(10-) as a function of pH of the solution and found that the anion is stable for the pH range 3-7. We have developed a colorimetric method for determining the concentration of U 4+ . In this method PW 11 O 39 sup(7-) is added to U 4+ in such a quantity that the mole ratio PWsub(11)Osub(39)sup(7-)/Usup(4+) exceeds 2 and the intensity of the 22.7 kK band (epsilon 1030 M -1 cm -1 ) is measured. In order to develop a continuous method to recover uranium, we have determined the amount of recovered PWsub(11)Osub(39)sup(7-) after decomposing [U(PW 11 O 39 ) 2 ]sup(10-) by adding either a base or an oxidizing agent. The percentage of PWsub(11)Osub(39)sup(7-) recovered was approximately 70% when a base was used and approximately 80% when K 2 S 2 O 8 was used. A colorimetric method for determining PW 11 O 39 sup(7-) has also been developed. (Author)

  20. Semi-automatic version of the potentiometric titration method for characterization of uranium compounds

    International Nuclear Information System (INIS)

    Cristiano, Bárbara F.G.; Delgado, José Ubiratan; Wanderley S da Silva, José; Barros, Pedro D. de; Araújo, Radier M.S. de; Dias, Fábio C.; Lopes, Ricardo T.

    2012-01-01

    The potentiometric titration method was used for characterization of uranium compounds to be applied in intercomparison programs. The method is applied with traceability assured using a potassium dichromate primary standard. A semi-automatic version was developed to reduce the analysis time and the operator variation. The standard uncertainty in determining the total concentration of uranium was around 0.01%, which is suitable for uranium characterization and compatible with those obtained by manual techniques. - Highlights: ► A semi-automatic potentiometric titration method was developed for U charaterization. ► K 2 Cr 2 O 7 was the only certified reference material used. ► Values obtained for U 3 O 8 samples were consistent with certified. ► Uncertainty of 0.01% was useful for characterization and intercomparison program.

  1. Contribution to the monitoring of workers exposed to non-transferable uranium compounds

    International Nuclear Information System (INIS)

    Camarasa, J.; Chalabreysse, J.

    1980-01-01

    After a short review of the present knowledge on uranium (metabolism, toxicity, principles of radiotoxicological monitoring), the authors' experience in the surveillance of workers exposed to natural non-transferable uranium compounds (oxides, tetrafluorides) is presented. When setting up urinary controls in a workers' population, a number of difficulties were met in the way of collecting urine samples, obtaining samples free of exogen contribution, interpreting results. The working environment was also studied: three types of pollution measurements were carried out: on the atmosphere at fixed places by measuring the radioactivity of air sample, on work-places and workers by chemical analysis and counting of uranium. Original graphs on work-place monitoring are up-dated regularly. Workers' surveillance by urinary and working condition controls are now well codified. However, further studies will be carried out on man, on working atmospheres, and on the substances handled. The surveillance will then cover working conditions from all points of view [fr

  2. Lattice and magnetic anisotropies in uranium intermetallic compounds

    DEFF Research Database (Denmark)

    Havela, L.; Mašková, S.; Adamska, A.

    2013-01-01

    Examples of UNiAlD and UCoGe illustrate that the soft crystallographic direction coincides quite generally with the shortest U-U links in U intermetallics. Added to existing experimental evidence on U compounds it leads to a simple rule, that the easy magnetization direction and the soft crystall...... crystallographic direction (in the sense of highest compressibility under hydrostatic pressure) must be mutually orthogonal....

  3. Insertion compounds of transition-metal and uranium oxides

    International Nuclear Information System (INIS)

    Chippindale, A.M.; Dickens, P.G.; Powell, A.V.

    1991-01-01

    Several transition-metal and actinide oxides, in which the metal occurs in a high oxidation state, have open covalent structures and are capable of incorporating alkali and other electropositive metals under mild conditions to form insertion compounds A x MO n . These are solids which have several features in common: Over a range of compositions, A x MO n exists as one or more stable or metastable phases in which the structure of the parent oxide MO n is largely retained and the insertion element A is accommodated interstitially. Insertion is accompanied by a redox process A=A i . + e - M in which M is reduced and the electronic properties of the parent oxide change to those typical of a mixed-valence compound. The insertion process xA + MO n = A x MO n can be reversed, at least to some extent, by chemical or electrochemical reaction, with retention of structure (topotactic reaction). This review concentrates on methods of synthesis, characterisation, crystal structure and thermochemistry of these insertion compounds. It updates and extends previous work. (author)

  4. Comprehensive uranium thiophosphate chemistry: Framework compounds based on pseudotetrahedrally coordinated central metal atoms

    International Nuclear Information System (INIS)

    Neuhausen, Christine; Panthoefer, Martin; Tremel, Wolfgang; Hatscher, Stephan T.; Urland, Werner

    2013-01-01

    The new ternary compounds UP 2 S 6 , UP 2 S 7 , U(P 2 S 6 ) 2 , and U 3 (PS 4 ) 4 were prepared from uranium metal, phosphorus pentasulfide, and sulfur at 700 C. The crystal structures were determined by single-crystal X-ray diffraction methods. UP 2 S 6 (I) crystallizes in the ZrP 2 S 6 structure type [tetragonal, P4 2 /m, a = 6.8058(7) Aa, c = 9.7597(14) Aa, Z = 2], which consists of central uranium(IV) atoms coordinated by P 2 S 6 4- anions (staggered conformation). The anions are two-dimensional connectors for four uranium cations arranged in one plane. The structure of UP 2 S 7 (II) [orthorhombic, Fddd, a = 8.9966(15) Aa, b = 15.2869(2) Aa, c = 30.3195(5) Aa, Z = 16] is closely related to the monoclinic ZrP 2 S 7 structure type. It consists of U 4+ cations linked by P 2 S 7 4- ligands, the resulting 3D network contains large pores (diameter approx. 3.5 x 16.7 Aa). In the previously reported compound U(P 2 S 6 ) 2 (III) [I4 1 /a, a = 12.8776(9) Aa, c = 9.8367(10) Aa, Z = 2], the metal atoms are coordinated by four bidentate P 2 S 6 2- ligands. This arrangement can be considered as a pseudotetrahedral coordination of the uranium atoms by the linear ligands. Three of the resulting diamondoid frameworks are inseparably interwoven in order to optimize space filling. U 3 (PS 4 ) 4 (IV) [I4 1 /acd, a = 10.7440(9) Aa, c = 19.0969(2) Aa, Z = 2] crystallizes in a defect variant of the PrPS 4 structure type, with 50 % of the U2 sites statistically occupied with uranium atoms. The resulting stoichiometry is U 3 (PS 4 ) 4 with tetravalent uranium atoms. The structure of U 3 (PS 4 ) 4 consists of uranium atoms connected by PS 4 3- groups, each PS 4 group linking four central uranium atoms. Vibrational spectra, which were recorded for I-III, show good agreement between the obtained results and the expected values for the anionic units, while magnetic measurements confirm the presence of tetravalent uranium. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGa

  5. The contribution of radioisotopes in secular equilibrium in the transport index of fissile uranium compounds in different enrichments

    International Nuclear Information System (INIS)

    Silva, Teresinha de Moraes da; Sordi, Gian M.A.A.

    2008-01-01

    Full text: This work shows the contribution of radioisotopes in secular equilibrium in the transport index (TI) of some fissile uranium compounds: uranium oxides UO 2 , U 3 O 8 and uranium silicide U 3 Si 2 , taking into account the different enrichment grades.The range of enrichment (E%) studied was 3,4,5,7,10,20,30,40,50,93 and 100. Initially, the cell of optimum moderation ratio was built, since it represents the most reactive of the system (consisting of uranium), with maximum infinitive multiplication factor k∞, in certain concentration of uranium for each enrichment. This was made using the computer program Gamtec II. The critical radius of a sphere was calculated for a cell of optimum moderation ratio, in order to calculate the critical mass of the uranium compound or of the uranium element for each specific enrichment. For this the program Citation was used. In this study it was calculated the smallest critical mass of the uranium compound or the smallest critical mass of the uranium element. The objective was to match the largest mass of the uranium with each specific enrichment. The largest safety mass corresponds to 45% the critical mass the compound uranium or uranium element. Then, we calculated the uranium element safety mass, which it related to a fifth of this mass to the value 50, which corresponds to criticality safety index (CSI). That is, 20% of the safety mass is the value where the transport is carried out with subcritical mass, going in favor of the security. From the uranium element safety mass (USM) was determined for each enrichment , and it was calculated the mass of 235 U, activity 235 U and dose rate of 235 U, the same items were calculated for the isotope 238 U. The total dose rate was calculated for two isotopes, and applying the transport index definition as the gamma dose rate for the distance of 1 m from the packed, it was determined the TI for 20% of the safety mass for each enrichment of the compound studied. The study of

  6. Uranium

    International Nuclear Information System (INIS)

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

    1992-01-01

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

  7. Interaction of erythrocytes and hexavalent uranium compounds -an autoanalytical study

    International Nuclear Information System (INIS)

    Stuart, W.I.; Shying, M.E.

    1980-05-01

    An automated analytical system was devised to measure the kinetics of hemolysis by uranyl compounds. Accurate plots of percentage hemolysis v. time were obtained; these, together with the corresponding differential curves, show that hemolysis of plasma-free erythrocytes is a two-stage process. The first stage of hemolysis is particularly affected by pH and anion content of uranyl solutions, and also by incubation of cell suspensions at 37 deg. before mixing with lysing solution. Complementary studies involving Coulter counting and microscopic observation established the general pattern of hemolysis and showed that cell agglutination is a prominent feature of the interaction of cells with uranyl solutions

  8. Poly thiophene hydrophobic and hydrophilic compounds, silver and iodine synthesized by plasma; Compuestos hidrofobicos e hidrofilicos de politiofeno, plata y yodo sintetizados por plasma

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, J.C.; Chavez, J.A. [IIM, UNAM, Circuito exterior, Ciudad Universitaria, 04510 Coyoacan, D.F. (Mexico); Olayo, M.G.; Cruz, G.J. [ININ, Apdo. Postal 18-1027, 11801 Mexico D.F. (Mexico)

    2007-07-01

    Compounds in thin films of poly thiophene with silver and poly thiophene doped with iodine and silver using splendor discharges were synthesized. It is studied the wettability of the compounds and its transport properties. It was found that the compounds can modify their hydrophilic to hydrophobic behavior controlling their surface ruggedness and the metallic content. The doped with iodine plays a fundamental paper in the modification of the ruggedness of the compounds. (Author)

  9. Critical parameters in the dump and heap leaching of gold, silver, copper and uranium: permeability, solution delivery and solution recovery

    Energy Technology Data Exchange (ETDEWEB)

    Lastra, M.K.; Chase, C.K.

    1984-02-01

    Critical to successful dump and heap leaching for gold, silver, copper and uranium are factors such as permeability, solution delivery to the ore, and solution recovery. This paper deals with possible techniques for successful accomplishment of these three factors. New developments as well as older techniques are discussed, together with rationals for use of some techniques in reference to others. The authors hope to present a checklist so that the ideal application to individual mine situations can be achieved. This involves a discussion of the merits of each different method and the situations for most logical application. It is hoped that such discussion will broaden the geographic areas where dump and heap leaching can be applied to include greater winter cold and tropical regions of large amounts of rainfall.

  10. Critical parameters in the dump and heap leaching of gold, silver, copper and uranium: permeability, solution delivery and solution recovery

    International Nuclear Information System (INIS)

    Lastra, M.K.; Chase, C.K.

    1984-01-01

    Critical to successful dump and heap leaching for gold, silver, copper and uranium are factors such as permeability, solution delivery to the ore, and solution recovery. This paper deals with possible techniques for successful accomplishment of these three factors. New developments as well as older techniques are discussed, together with rationals for use of some techniques in reference to others. The authors hope to present a checklist so that the ideal application to individual mine situations can be achieved. This involves a discussion of the merits of each different method and the situations for most logical application. It is hoped that such discussion will broaden the geographic areas where dump and heap leaching can be applied to include greater winter cold and tropical regions of large amounts of rainfall

  11. Synthesis of graphite intercalation compound of group VI metals and uranium hexafluorides

    International Nuclear Information System (INIS)

    Fukui, Toshihiro; Hagiwara, Rika; Ema, Keiko; Ito, Yasuhiko

    1993-01-01

    Systematic investigations were made on the synthesis of graphite intercalation compounds of group VI transition metals (W and Mo) and uranium hexafluorides. The reactions were performed by interacting liquid or gaseous metal hexafluorides with or without elemental fluorine at ambient temperature. The degree of intercalation of these metal fluorides depends on the formation enthalpy of fluorometallate anion from the original metal hexafluoride, as has been found for other intercalation reactions of metal fluorides. (author)

  12. Benchmarking the DFT+U method for thermochemical calculations of uranium molecular compounds and solids.

    Science.gov (United States)

    Beridze, George; Kowalski, Piotr M

    2014-12-18

    Ability to perform a feasible and reliable computation of thermochemical properties of chemically complex actinide-bearing materials would be of great importance for nuclear engineering. Unfortunately, density functional theory (DFT), which on many instances is the only affordable ab initio method, often fails for actinides. Among various shortcomings, it leads to the wrong estimate of enthalpies of reactions between actinide-bearing compounds, putting the applicability of the DFT approach to the modeling of thermochemical properties of actinide-bearing materials into question. Here we test the performance of DFT+U method--a computationally affordable extension of DFT that explicitly accounts for the correlations between f-electrons - for prediction of the thermochemical properties of simple uranium-bearing molecular compounds and solids. We demonstrate that the DFT+U approach significantly improves the description of reaction enthalpies for the uranium-bearing gas-phase molecular compounds and solids and the deviations from the experimental values are comparable to those obtained with much more computationally demanding methods. Good results are obtained with the Hubbard U parameter values derived using the linear response method of Cococcioni and de Gironcoli. We found that the value of Coulomb on-site repulsion, represented by the Hubbard U parameter, strongly depends on the oxidation state of uranium atom. Last, but not least, we demonstrate that the thermochemistry data can be successfully used to estimate the value of the Hubbard U parameter needed for DFT+U calculations.

  13. Reaction of Tris(cyclopentadienyl)uranium compounds with amines, azides, and related ligands

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, R.K.

    1989-12-01

    The trivalent uranium compound, (MeC{sub 5}H{sub 4}){sub 3}U(thf), serves as a one- or two-electron reducing agent towards azides, RN{sub 3}. These reactions produce either the uranium(IV) azide, (MeC{sub 5}H{sub 4}){sub 3}UN{sub 3}, or uranium(V) imides, (MeC{sub 5}H{sub 4}){sub 3}UNR. The role of steric and electronic effects upon this reaction has been investigated using several series of azides. For Me{sub 3}XN{sub 3}, the imides are produced when X = C or Si, both products are formed when X = Ge, and the azide is produced when X = Sn. For Ph{sub 3}XN{sub 3}, the azide is produced when X = C or Sn. For Ph{sub 3-x}CH{sub 3}N{sub 3}, the imide is produced when x = 2 and both compounds are produced when x = 1. For substituted phenylazides, RC{sub 6}H{sub 4}N{sub 3}, only the imides are produced. The magnetic properties of uranium diimides, ((MeC{sub 5}H{sub 4}){sub 3}U){sub 2}({mu}-NRN), were investigated. Several uranium(III) amines, (MeC{sub 5}H{sub 4}){sub 3}U(NH{sub 2}R), were produced from (MeC{sub 5}H{sub 4}){sub 3}U(thf) and RNH{sub 2}, and NH{sub 3} was found to be a better ligand towards (MeC{sub 5}H{sub 4}){sub 3}U than is PMe{sub 3}.

  14. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

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

  15. Uranium

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  16. Uranium

    International Nuclear Information System (INIS)

    Mackay, G.A.

    1978-01-01

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

  17. Uranium

    International Nuclear Information System (INIS)

    1982-01-01

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

  18. Uranium

    International Nuclear Information System (INIS)

    Stewart, E.D.J.

    1974-01-01

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

  19. Uranium

    International Nuclear Information System (INIS)

    Toens, P.D.

    1981-03-01

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

  20. Study of resolution enhancement methods for impurities quantitative analysis in uranium compounds by XRF

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Clayton P.; Salvador, Vera L.R.; Cotrim, Marycel E.B.; Pires, Maria Ap. F.; Scapin, Marcos A., E-mail: clayton.pereira.silva@usp.b [Instituto de Pesquisas Energeticas e Nucleares (CQMA/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente

    2011-07-01

    X-ray fluorescence analysis is a technique widely used for the determination of both major and trace elements related to interaction between the sample and radiation, allowing direct and nondestructive analysis. However, in uranium matrices these devices are inefficient because the characteristic emission lines of elements like S, Cl, Zn, Zr, Mo and other overlap characteristic emission lines of uranium. Thus, chemical procedures to separation of uranium are needed to perform this sort of analysis. In this paper the deconvolution method was used to increase spectra resolution and correct the overlaps. The methodology was tested according to NBR ISO 17025 using a set of seven certified reference materials for impurities present in U3O8 (New Brunswick Laboratory - NBL). The results showed that this methodology allows quantitative determination of impurities such as Zn, Zr, Mo and others, in uranium compounds. The detection limits were shorter than 50{mu}g. g{sup -1} and uncertainty was shorter than 10% for the determined elements. (author)

  1. Study of resolution enhancement methods for impurities quantitative analysis in uranium compounds by XRF

    International Nuclear Information System (INIS)

    Silva, Clayton P.; Salvador, Vera L.R.; Cotrim, Marycel E.B.; Pires, Maria Ap. F.; Scapin, Marcos A.

    2011-01-01

    X-ray fluorescence analysis is a technique widely used for the determination of both major and trace elements related to interaction between the sample and radiation, allowing direct and nondestructive analysis. However, in uranium matrices these devices are inefficient because the characteristic emission lines of elements like S, Cl, Zn, Zr, Mo and other overlap characteristic emission lines of uranium. Thus, chemical procedures to separation of uranium are needed to perform this sort of analysis. In this paper the deconvolution method was used to increase spectra resolution and correct the overlaps. The methodology was tested according to NBR ISO 17025 using a set of seven certified reference materials for impurities present in U3O8 (New Brunswick Laboratory - NBL). The results showed that this methodology allows quantitative determination of impurities such as Zn, Zr, Mo and others, in uranium compounds. The detection limits were shorter than 50μg. g -1 and uncertainty was shorter than 10% for the determined elements. (author)

  2. Antibacterial and DNA cleavage activity of carbonyl functionalized N-heterocyclic carbene-silver(I) and selenium compounds

    Science.gov (United States)

    Haque, Rosenani A.; Iqbal, Muhammad Adnan; Mohamad, Faisal; Razali, Mohd R.

    2018-03-01

    The article describes syntheses and characterizations of carbonyl functionalized benzimidazolium salts, I-IV. While salts I-III are unstable at room temperature, salt IV remained stable and was further utilised to form N-heterocyclic carbene (NHC) compounds of silver(I), V and VI, and selenium compound, VII respectively. Compounds IV-VII were tested for their antibacterial potential against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Salt IV shows a very low inhibition potential (minimum inhibitory concentration, MIC 500 μg/mL) compared to the respective silver(I)-NHC, V and VI (MIC 31.25 μg/mL against both, E. coli and S. aureus) and selenium compound, VII (MIC 125 μg/mL against E. coli and 62.50 μg/mL against S. aureus). In DNA cleavage abilities, all the test compounds cleave DNA in which the VII cleaves the DNA at the faster rate. Meanwhile, the silver(I)-NHC complexes V and VI act at the same mode and pattern of DNA cleavage while VII is similar to IV.

  3. Water Solubility of Plutonium and Uranium Compounds and Residues at TA-55

    International Nuclear Information System (INIS)

    Reilly, Sean Douglas; Smith, Paul Herrick; Jarvinen, Gordon D.; Prochnow, David Adrian; Schulte, Louis D.; DeBurgomaster, Paul Christopher; Fife, Keith William; Rubin, Jim; Worl, Laura Ann

    2016-01-01

    Understanding the water solubility of plutonium and uranium compounds and residues at TA-55 is necessary to provide a technical basis for appropriate criticality safety, safety basis and accountability controls. Individual compound solubility was determined using published solubility data and solution thermodynamic modeling. Residue solubility was estimated using a combination of published technical reports and process knowledge of constituent compounds. The scope of materials considered includes all compounds and residues at TA-55 as of March 2016 that contain Pu-239 or U-235 where any single item in the facility has more than 500 g of nuclear material. This analysis indicates that the following materials are not appreciably soluble in water: plutonium dioxide (IDC=C21), plutonium phosphate (IDC=C66), plutonium tetrafluoride (IDC=C80), plutonium filter residue (IDC=R26), plutonium hydroxide precipitate (IDC=R41), plutonium DOR salt (IDC=R42), plutonium incinerator ash (IDC=R47), uranium carbide (IDC=C13), uranium dioxide (IDC=C21), U 3 O 8 (IDC=C88), and uranium filter residue (IDC=R26). This analysis also indicates that the following materials are soluble in water: plutonium chloride (IDC=C19) and uranium nitrate (IDC=C52). Equilibrium calculations suggest that PuOCl is water soluble under certain conditions, but some plutonium processing reports indicate that it is insoluble when present in electrorefining residues (R65). Plutonium molten salt extraction residues (IDC=R83) contain significant quantities of PuCl 3 , and are expected to be soluble in water. The solubility of the following plutonium residues is indeterminate due to conflicting reports, insufficient process knowledge or process-dependent composition: calcium salt (IDC=R09), electrorefining salt (IDC=R65), salt (IDC=R71), silica (IDC=R73) and sweepings/screenings (IDC=R78). Solution thermodynamic modeling also indicates that fire suppression water buffered with a commercially-available phosphate

  4. Water Solubility of Plutonium and Uranium Compounds and Residues at TA-55

    Energy Technology Data Exchange (ETDEWEB)

    Reilly, Sean Douglas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States; Smith, Paul Herrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States; Jarvinen, Gordon D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States; Prochnow, David Adrian [Los Alamos National Lab. (LANL), Los Alamos, NM (United States; Schulte, Louis D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States; DeBurgomaster, Paul Christopher [Los Alamos National Lab. (LANL), Los Alamos, NM (United States; Fife, Keith William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States; Rubin, Jim [Los Alamos National Lab. (LANL), Los Alamos, NM (United States; Worl, Laura Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States

    2016-06-13

    Understanding the water solubility of plutonium and uranium compounds and residues at TA-55 is necessary to provide a technical basis for appropriate criticality safety, safety basis and accountability controls. Individual compound solubility was determined using published solubility data and solution thermodynamic modeling. Residue solubility was estimated using a combination of published technical reports and process knowledge of constituent compounds. The scope of materials considered includes all compounds and residues at TA-55 as of March 2016 that contain Pu-239 or U-235 where any single item in the facility has more than 500 g of nuclear material. This analysis indicates that the following materials are not appreciably soluble in water: plutonium dioxide (IDC=C21), plutonium phosphate (IDC=C66), plutonium tetrafluoride (IDC=C80), plutonium filter residue (IDC=R26), plutonium hydroxide precipitate (IDC=R41), plutonium DOR salt (IDC=R42), plutonium incinerator ash (IDC=R47), uranium carbide (IDC=C13), uranium dioxide (IDC=C21), U3O8 (IDC=C88), and uranium filter residue (IDC=R26). This analysis also indicates that the following materials are soluble in water: plutonium chloride (IDC=C19) and uranium nitrate (IDC=C52). Equilibrium calculations suggest that PuOCl is water soluble under certain conditions, but some plutonium processing reports indicate that it is insoluble when present in electrorefining residues (R65). Plutonium molten salt extraction residues (IDC=R83) contain significant quantities of PuCl3, and are expected to be soluble in water. The solubility of the following plutonium residues is indeterminate due to conflicting reports, insufficient process knowledge or process-dependent composition: calcium salt (IDC=R09), electrorefining salt (IDC=R65), salt (IDC=R71), silica (IDC=R73) and sweepings/screenings (IDC=R78). Solution thermodynamic modeling also indicates that fire suppression water buffered with a

  5. Several experimental applications of gamma ray spectrometry on the analysis of uranium compounds

    International Nuclear Information System (INIS)

    Korob, Ricardo O.; Blasiyh Nuno, Guillermo A.

    2002-01-01

    Several experimental applications of gamma ray spectrometry on the analysis of uranium compounds and materials containing it are studied. Special attention is devoted to the correlation between experimental spectra and the decay chains of 235 U and 238 U contained in the analyzed samples. The following applications are discussed: enrichment determination without using calibration standards, determination of uranium concentration, intensities of the gamma rays emitted by the nuclides present in the decay chains of study and the activity of such nuclides. Because of its importance, detailed discussion about the former one is shown. In addition, preliminary results regarding the emission probabilities of the most important gamma rays of 234m Pa are also informed. (author)

  6. A gravimetric method for the determination of oxygen in uranium oxides and ternary uranium oxides by addition of alkaline earth compounds

    International Nuclear Information System (INIS)

    Fujino, Takeo; Tagawa, Hiroaki; Adachi, Takeo; Hashitani, Hiroshi

    1978-01-01

    A simple gravimetric determination of oxygen in uranium oxides and ternary uranium oxides is described. In alkaline earth uranates which are formed by heating in air at 800-1100 0 C, uranium is in the hexavalent state over certain continuous ranges of alkaline earth-to-uranium ratios. Thus, if an alkaline earth uranate or a compound containing an alkaline earth element, e.g. MgO, is mixed with the oxide sample and heated in air under suitable conditions, oxygen can be determined from the weight change before and after the reaction. The standard deviation of the O:U ratio for a UOsub(2+x) test sample is +-0.0008-0.001, if a correction is applied for atmospheric moisture absorbed during mixing. (Auth.)

  7. FROM THE SIGNIFICANT ST. JOACHIMSTAL SILVER AND URANIUM PIT, JÁCHYMOV, TO RADON SPA IN SAXON CZECH „RUDNA GORA“

    Directory of Open Access Journals (Sweden)

    Branislav Šebečić

    2006-12-01

    Full Text Available At he beginning of the 16th century Saxon miners discovered silver ore in the small settlement Konnradsgrűn at south-west slopes of Erzgebirge in the valley Joachimsthal named after the patron saint St. Joachim. The silver coin was named Jochymst(haler. The mine and the settlement became a free royal mining city where, thanks to the mint, one of the richest noble families von Schlick arose. 554,44 tons of silver were produced from 1517 till 1900. Together with silver ore cobalt and lead ore were exploited ( in significant quantities from 18th till 19th century and after that period nickel, bismuth and arsenic ore (19th century. From the listed ores cobalt was produced in largest quantities for enamel production; 1824,23 tons in the period from 1775 till 1851. Next to these ores uranite ore (urani/ni/t was discovered in the mine. The ore was first used to produce uranium colours used for ceramics, glass and paintings and later to obtain uranium; 8500 tons since 1853 till 1964, a part of which was worked up into radium, to obtain 100gr Ra-. Thanks to the discovery of radioactive- radon water the mine is still active because 20 miners are employed to maintain the part of it from which the radon water is exploited. Jachymov and its surroundigs have become a famous radioactive thermal sanatorium in Europe (the paper is published in Croatian.

  8. Toxic influence of silver and uranium salts on activated sludge of wastewater treatment plants and synthetic activated sludge associates modeled on its pure cultures.

    Science.gov (United States)

    Tyupa, Dmitry V; Kalenov, Sergei V; Skladnev, Dmitry A; Khokhlachev, Nikolay S; Baurina, Marina M; Kuznetsov, Alexander Ye

    2015-01-01

    Toxic impact of silver and uranium salts on activated sludge of wastewater treatment facilities has been studied. Some dominating cultures (an active nitrogen fixer Agrobacterium tumifaciens (A.t) and micromyces such as Fusarium nivale, Fusarium oxysporum, and Penicillium glabrum) have been isolated and identified as a result of selection of the activated sludge microorganisms being steadiest under stressful conditions. For these cultures, the lethal doses of silver amounted 1, 600, 50, and 300 µg/l and the lethal doses of uranium were 120, 1,500, 1,000, and 1,000 mg/l, respectively. A.tumifaciens is shown to be more sensitive to heavy metals than micromyces. Synthetic granular activated sludge was formed on the basis of three cultures of the isolated micromyces steadiest against stress. Its granules were much more resistant to silver than the whole native activated sludge was. The concentration of silver causing 50 % inhibition of synthetic granular activated sludge growth reached 160-170 μg/l as far as for the native activated sludge it came only to 100-110 μg/l.

  9. Spectrographic determination of zirconium, niobium, rhodium, ruthenium, tantalum, and tungsten in uranium and its compounds

    International Nuclear Information System (INIS)

    Alduan, F.A.; Capdevila, C.

    1976-01-01

    The determination of Nb, Rh, Ru, Ta, W and Zr in uranium and its compounds has been studied, using the carrier distillation method with either AgCl or AgCl-SrF 2 (4:3) as carrier. In order to get the best sensitivity, the influence of the carrier concentration, the dc arc intensity and several controlled atmospheres on the variation of the line to background ratio of intensities has been considered. With the most suitable conditions, the sensitivities achieved for the considered elements are in the range 1-10 ppm. (author)

  10. Thermodynamic data for uranium and thorium intermetallic compounds: A historical perspective

    International Nuclear Information System (INIS)

    Alcock, C.B.

    1989-01-01

    The development of quantitative information concerning the stabilities of uranium and thorium intermetallic compounds since the publication of Rough and Bauer's phase diagram compilation are reviewed. During this era a number of high temperature measurement techniques have been developed, from gas/solid equilibration to mass spectrometry and from high temperature calorimetry to solid state electrochemistry, and the growth of quantitative information has run parallel to this evolution. The amount of experimental effort now appears to be declining, and the task presently of major importance is to integrate and rationalize the quantitative information, an effort which will undoubtedly lead to new experimental initiatives. (orig.)

  11. Uranium

    International Nuclear Information System (INIS)

    Whillans, R.T.

    1981-01-01

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

  12. Spectrographic determination of lanthanides in high-purity uranium compounds, after chromatographic separation by alumina-hydrofluoric acid

    International Nuclear Information System (INIS)

    Lordello, A.R.; Abrao, A.

    1979-01-01

    A method is presented for the determination of fourteen rare earth elements in high-purity uranium compounds by emission spectrography. The rare earths are chromatographically separated from uranium by using alumina-hydrofluoric acid. Lanthanum is used both as collector and internal standard. The technique of excitation involves a total consumption of the sample in a 17 ampere direct current arc. The range of determination is about 0.005 to 0.5 μg/g uranium. The coefficient of variation for Pr, Ho, Dy, Er, Tm, Lu, Gd and Tb amounts to 10%. (Author) [pt

  13. Reference values and their application to the monitoring of occupational exposure to natural uranium compounds

    International Nuclear Information System (INIS)

    1986-09-01

    Natural uranium compounds, which enter the oxide fuel cycle offer physico-chemical characteristics dependent on their structure and their production process. These characteristics govern their biological behaviour and the degree of their radioactive and chemical toxicity. The monitoring of workers occupationnally exposed to these compounds is carried out by bioassays; in order to get the best interpretation, the resulting data must be compared to reference values. These values must be closely related to the type of contaminant and the real exposure conditions. In this report, the occupational medicine services working group has examined the possibilities of obtaining such reference values and suggests recommendations and operational values covering most situations found in routine monitoring [fr

  14. Overview of toxicity data and risk assessment methods for evaluating the chemical effects of depleted uranium compounds

    International Nuclear Information System (INIS)

    Hartmann, H.M.; Monette, F.A.; Avci, H.I.

    2000-01-01

    In the United States, depleted uranium is handled or used in several chemical forms by both governmental agencies and private industry (primarily companies producing and machining depleted uranium metal for military applications). Human exposure can occur as a result of handling these compounds, routine low-level effluent releases to the environment from processing facilities, or materials being accidentally released from storage locations or during processing or transportation. Exposure to uranium can result in both chemical and radiological toxicity, but in most instances chemical toxicity is of greater concern. This article discusses the chemical toxic effects from human exposure to depleted uranium compounds that are likely to be handled during the long-term management and use of depleted uranium hexafluoride (UF 6 ) inventories in the United States. It also reviews representative publications in the toxicological literature to establish appropriate reference values for risk assessments. Methods are described for evaluating chemical toxicity caused by chronic low-level exposure and acute exposure. Example risk evaluations are provided for illustration. Preliminary results indicate that chemical effects of chronic exposure to uranium compounds under normal operating conditions would be negligibly small. Results also show that acute exposures under certain accident conditions could cause adverse chemical effects among the populations exposed.

  15. Fluorination of uranium compounds by gaseous bromine trifluoride and a bromine-fluorine mixture

    International Nuclear Information System (INIS)

    Sakurai, Tsutomu

    1976-03-01

    This report summarizes the studies of fluorination of uranium compounds by gaseous BrF 3 and a Br 2 -F 2 mixture, which were carried out in Fluorine Chemistry Laboratory of JAERI in connection with the reprocessing method of nuclear fuels. Although thermodynamically more stable than F 2 , BrF 3 has higher reactivity at relatively low temperatures: fluorination of uranium compounds can be carried out at 100 0 -- 200 0 C by using gaseous BrF 3 . This fluorination temperature is lower than those of F 2 , BrF 5 , ClF and SF 4 , and close to that of ClF 3 . The usage of BrF 3 has however the drawbacks that it requires additional devices to heat the corrosive liquid and to remove Br 2 produced as a byproduct. In order to eliminate the difficulties indicated, a new method of fluorination was developed - the use of a Br 2 -F 2 mixture. Addition of small amounts of Br 2 to the fluorine flow (about 6% in relation to the fluorine concentration) gives marked effects on the rate of fluorination. (auth.)

  16. Reactions of uranium (III) and (IV) compounds with ketones, nitriles and acid chlorides. Towards a use of uranium complexes in organic synthesis

    International Nuclear Information System (INIS)

    Adam, Raymond

    1993-01-01

    In this research thesis, the author shows that various organic molecules can be interestingly transformed into uranium complexes with degrees of oxidation of +3 or +4. In a first part, the author describes reactions of carbonyl compounds with the UCl 4 -Na(Hg) reducing system. Then, he addresses reductions of ketones, nitriles and acid chlorides by a uranium (III) complex: Cp 3 U(THF). The third part reports a detailed study of the reduction of ketones by U(BH 4 ) 4 [fr

  17. Determination of oxygen in uranium compounds using sulfur monochloride; Dosage de l'oxygene dans les composes de l'uranium par la methode au monochlorure de soufre

    Energy Technology Data Exchange (ETDEWEB)

    Baudin, G; Besson, J; Blum, P L; Tran-Van, Danh [Commisariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1964-07-01

    The authors have described in an other paper (Anal. Chim. Acta, in press) a method for oxygen determination in uranium compounds, in which the sample is attacked by sulfur monochloride. The present paper is concerned with the experimental aspects of the method: apparatus procedure. (authors) [French] Les auteurs ont decrit dans une autre publication (Anal. Chim. Acta) a paraitre, une methode de dosage de l'oxygene dans les composes de l'uranium par attaque par le monochlorure de soufre, La presente note a pour but d'en preciser les techniques experimentale: appareillage, mode operatoire. (auteurs)

  18. Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R M

    1976-01-01

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

  19. Synthesis of silver nanoparticles deposited on silica by γ-irradiation and preparation of PE/Ag nano compound masterbatches

    Science.gov (United States)

    Nguyen, Thi Kim Lan; Trinh Nguyen, Thuy Ai; Phu Dang, Van; Duy Nguyen, Ngoc; Le, Anh Quoc; Hien Nguyen, Quoc

    2013-12-01

    Silver nanoparticles (AgNPs) deposited on silica were synthesized by gamma Co-60 irradiation of Ag+ dispersion in silica/ethanol/water mixture (9/80/20:w/v/v). The reduction of Ag+ is occurred by hydrated electron (e-aq) and hydrogen atom (H•) generated during radiolysis of ethanol/water. The conversion doses (Ag+ → Ag0) were determined by UV-Vis spectroscopy. The synthesized AgNPs/silica were characterized by transmission electron microscopy (TEM) and x-ray diffraction (XRD), which showed the size of AgNPs to be in the range of 5-40 nm for Ag+ concentrations from 5 to 20 mM. Masterbatches of PE/AgNPs/silica compound with silver content from 250 to 1000 mg kg-1 were also prepared. These masterbatches can be suitably used for various applications such as antimicrobial food containers and packing films, etc.

  20. Synthesis of silver nanoparticles deposited on silica by γ-irradiation and preparation of PE/Ag nano compound masterbatches

    International Nuclear Information System (INIS)

    Nguyen, Thi Kim Lan; Dang, Van Phu; Nguyen, Ngoc Duy; Le, Anh Quoc; Nguyen, Quoc Hien; Nguyen, Thuy Ai Trinh

    2013-01-01

    Silver nanoparticles (AgNPs) deposited on silica were synthesized by gamma Co-60 irradiation of Ag + dispersion in silica/ethanol/water mixture (9/80/20:w/v/v). The reduction of Ag + is occurred by hydrated electron (e − aq ) and hydrogen atom (H • ) generated during radiolysis of ethanol/water. The conversion doses (Ag + → Ag 0 ) were determined by UV–Vis spectroscopy. The synthesized AgNPs/silica were characterized by transmission electron microscopy (TEM) and x-ray diffraction (XRD), which showed the size of AgNPs to be in the range of 5–40 nm for Ag + concentrations from 5 to 20 mM. Masterbatches of PE/AgNPs/silica compound with silver content from 250 to 1000 mg kg −1 were also prepared. These masterbatches can be suitably used for various applications such as antimicrobial food containers and packing films, etc. (paper)

  1. Adsorbed States of phosphonate derivatives of N-heterocyclic aromatic compounds, imidazole, thiazole, and pyridine on colloidal silver: comparison with a silver electrode.

    Science.gov (United States)

    Podstawka, Edyta; Olszewski, Tomasz K; Boduszek, Bogdan; Proniewicz, Leonard M

    2009-09-03

    Here, we report a systematic surface-enhanced Raman spectroscopy (SERS) study of the structures of phosphonate derivatives of the N-heterocyclic aromatic compounds imidazole (ImMeP ([hydroxy(1H-imidazol-5-yl)methyl]phosphonic acid) and (ImMe)(2)P (bis[hydroxy-(1H-imidazol-4-yl)-methyl]phosphinic acid)), thiazole (BAThMeP (butylaminothiazol-2-yl-methyl)phosphonic acid) and BzAThMeP (benzylaminothiazol-2-yl-methyl)phosphonic acid)), and pyridine ((PyMe)(2)P (bis[(hydroxypyridin-3-yl-methyl)]phosphinic acid)) adsorbed on nanometer-sized colloidal particles. We compared these structures to those on a roughened silver electrode surface to determine the relationship between the adsorption strength and the geometry. For example, we showed that all of these biomolecules interact with the colloidal surface through aromatic rings. However, for BzAThMeP, a preferential interaction between the benzene ring and the colloidal silver surface is observed more so than that between the thiazole ring and this substrate. The PC(OH)C fragment does not take part in the adsorption process, and the phosphonate moiety of ImMeP and (ImMe)(2)P, being removed from the surface, only assists in this process.

  2. Uranium

    International Nuclear Information System (INIS)

    Perkin, D.J.

    1982-01-01

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

  3. Uranium

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  4. 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 ...

  5. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

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

  6. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

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

  7. Uranium conversion

    International Nuclear Information System (INIS)

    Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina

    2006-03-01

    FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF 6 and UF 4 are present require equipment that is made of corrosion resistant material

  8. Determination of metallic impurities in nuclearly pure uranium compounds by electrothermal spectrophotometry

    International Nuclear Information System (INIS)

    Franco, M.B.

    1986-01-01

    Atomic absorption spectrometry, with electrothermal atomization, has been used for the determination of Al, Cd, Cr, Fe, Mn and Ni in uranium oxide standards. The analysis were performed without sample dissolution and without uranium chemical separation. This technique is adequate for the qualification of nuclearly pure uranium, according to the standard specifications. (Author) [pt

  9. The mode of occurrence of gold and silver in the Dominian Reef and their response to cyanidation after pressure leading

    International Nuclear Information System (INIS)

    Glatthaar, C.W.; Feather, C.E.

    1985-01-01

    Gold and silver in the Upper Reef of the Dominion Group in the Afrikander Lease area occur in several minerals. Native gold, electrum, and amalgam are the main gold bearers, whereas silver, in addition to being present in the above alloys, is also represented by native silver, in mercurian silver (arquerite), acanthite, stromeyerite, and a bismuth-silver sulphide (schaba-chite or pavionite), and in solid solution in galena. Only minute quantities of these silver-bearing minerals were found, and attempts to evaluate their relative abundances in the ore proved to be difficult. It was possible, however, by use of an electron microprobe, to quantify the silver contents in electrum, amalgam, mercurian silver, and galena. Mass-balance studies based on the calculated galena content suggest that about half of the total silver is associated with galena in solid solution. In practice, the uranium present in the conglomerates of the Dominion Group is extracted first. Because of the refractory nature of the uranium-bearing minerals, a leach at high temperature and high pressure is recommended. While this pressure leach is beneficial to the subsequent cyanidation of gold, a large proportion of the silver present is rendered refractory. The poor recoveries of silver are believed to be due close association of silver and galena. It is believed that silver is released during the dissolution of galena, acanthite, other silver sulphides, and native silver, and subsequently precipitated either as an insoluble complex silver-iron sulphate (argentojarosite) or in solid solution in jarosite (potassium-iron sulphate). Neither compound is amenable to cyanidation. A mixture of plumbojarosite (lead-iron sulphate) and jarosite were seen to form protective coatings on galena particles, and may occlude other silver-bearing minerals in the same manner. In contrast, finely divided gold particles are liberated from pyrite and other minerals during pressure leaching and become readily available to

  10. Silver Cation Coordination Study to AsW9 Ligand – A Trilacunar Arsenotungstate Compound

    Directory of Open Access Journals (Sweden)

    Berta Lavinia

    2017-06-01

    Full Text Available Objective: The main objective of this research is to find the coordination ratio between AsW9 and Ag+, as a preliminary study for synthesizing a new silver-arsenotungstate complex. Material and method: The ligand:cation molar ratio in complexes was determined by conductometric and potentiometric titrations of AsW9 with silver salts: CH3COOAg, AgNO3. Results: The ratio was obtained from the inflexion points of the curves when molar ratio was plotted versus conductivity, or from the equivalence point when silver added volume was plotted versus pH value. Each graphic shows one point of inflexion corresponding to 1:1.54 ratio of AsW9:Ag+. In the same manner, the equivalent volumes determined by graphical method gave the ratio 1:1.53. The spectral results confirmed that a AsW9:Ag+ complex was formed since the ligand absorption maxima values have been changed from 190 nm to 197 nm in the case of using AgNO3 and 196 nm for CH3COOAg corresponding to the W=Od bond, and from 246.5 nm to 274 nm (AgNO3 and 270 nm (CH3COO-Ag+ for the W-Ob,c-W bond. Conclusions: Silver cation exhibit a preference for AsW9 in a ratio of 3 to 2. This ratio can be associated to a sandwich type arrangement, with two trilacunary Keggin building blocks incorporating 3 metal cations in a tetrahedral geometry.

  11. Liquid-Mercury Free Silver Solid Amalgam Electrode - Tool for Electroanalysis of Organic Compounds

    Czech Academy of Sciences Publication Activity Database

    Šelešovská-Fadrná, R.; Navrátil, Tomáš; Vlček, Milan

    2007-01-01

    Roč. 52, č. 6 (2007), s. 911-929 ISSN 0009-2223 R&D Projects: GA ČR GA203/07/1195; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40500505 Keywords : ascorbic acid * solid silver amalgam electrodes * cysteine * voltammetry Subject RIV: CG - Electrochemistry Impact factor: 0.529, year: 2007

  12. Study on the characterization and thermal decomposition of uranium compounds by thermogravimetry (TG) and differential scanning calorimetry (DSC)

    International Nuclear Information System (INIS)

    Dantas, J.M.; Abrao, A.

    1981-04-01

    A contribution to the characterization of several uranium compounds obtained at the IPEN' Uranium Pilot Plant is given. Particularly, samples of ammonium diuranate (ADU) and uranium oxides were studied. The main objective was to know the stoichiometry of the ADU and the oxides resulting from its thermal transformation. ADU samples were prepared by batchwise precipitation, stationary dewatering into stove and batchwise thermal decomposition, or, alternatively, continuous precipitation, continuous filtration, continuous drying and continuous thermal decomposition inside a temperature gradient electrical furnace. All ADU were precipitated using NH 3 gas from uranul sulfate or uranyl nitrate solutions. The thermal decomposition of ADU and uranium oxides were studied in an air atmosphere by thermogravimetry (TG) and differential scanning calorimetry (DSC). Any correlation between the parameters of precipitation, drying, calcination and the hystory of the obtaintion of the several uraniumm compounds and their initial and final composition was looked for. Heating program was established to have the U 3 O 8 oxide as the final product. Intermediary phases were tentatively identified. Temperatures at which occurred the absorption water elimination, crystallization water elimination, evolution or oxidation of NH 3 , decomposition of NO -3 ion and oxygen evolution and the exo- and endothermic process for each sample were identified. (Author) [pt

  13. Hepatoprotective effect of engineered silver nanoparticles coated bioactive compounds against diethylnitrosamine induced hepatocarcinogenesis in experimental mice.

    Science.gov (United States)

    Prasannaraj, Govindaraj; Venkatachalam, Perumal

    2017-02-01

    Nanoparticle based drug delivery can rapidly improves the therapeutic potential of anti-cancer agents. The present study focused to evaluate the hepatoprotective activity of silver nanoparticles (AgNPs) synthesized using aqueous extracts of Andrographis paniculata leaves (ApAgNPs) and Semecarpus anacardium nuts (SaAgNPs) against diethylnitrosamine (DEN) induced liver cancer in mice model. The physico-chemical properties of synthesized AgNPs were characterized by Fourier transform infrared (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), X-ray Diffraction (XRD), Energy Dispersive X-ray (EDX) spectrum, Zeta potential and Dynamic Light Scattering (DLS) analysis. The surface plasmon resonance (SPR) absorption spectrum revealed a strong peak at 420nm for both SaAgNPs and ApAgNPs. FTIR results exhibited the presence of possible functional groups in the synthesized AgNPs. TEM analysis determined the hexagonal, and spherical shape of the synthesized silver nanoparticles. The XRD and SAED pattern confirmed the crystalline nature and crystalline size of the AgNPs. EDX result clearly showed strong silver signals in the range between 2 and 4keV. Zeta potential measurements indicated a sharp peak at -3.93 and -13.8mV for ApAgNPs and SaAgNPs, respectively. DLS measurement expressed the particle size distribution was 70 and 60nm for ApAgNPs and SaAgNPs, respectively. DEN (20mg/kg b.wt.) was subjected to induce liver cancer in mice for 8weeks and treated with biosynthesized silver nanoparticles. Interestingly, ApAgNPs and SaAgNPs treated DEN induced animal groups show a decreased level of aspartate amino transferase (AST), alanine amino transferase (ALT), serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) activity and elevated level of catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST) and superoxide dismutase (SOD) activity over untreated DEN control

  14. Spectroscopic studies of organometallic compounds on single crystal metal surfaces: Surface acetylides of silver (110)

    Science.gov (United States)

    Madix, Robert J.

    The nature of compounds formed by the reaction of organic molecules with metal surfaces can be studied with a battery of analytical methods based on both physicals and chemical understanding. In this paper the application of UPS, XPS, LEED and EELS as well as temperature programmed reaction spectroscopy (TPRS) and chemical titration methods to the characterization of surface complexes is discussed. Particular emphasis is given to the reaction of acetylene with a single crystal surface of silver, Ag(110). Previous work has shown that this surface, when clean, is unreactive to hydrocarbons, alcohols and carboxylic acids under ultra high vacuum conditions. Preadsorption of oxygen, however, renders the surface reactive, and a wide variety of organometallic surface compounds can be formed. As expected then, no stable adsorption state and no reaction was observed with clean Ag(110) following room temperature exposure to acetylene. Following exposure at 150 K, however, a weekly bound chemisorption state was observed to desorb at 195 K, indicating a binding energy to the surface of approximately 12 kcal/gmole. Reaction with preadsorbed oxygen gave water formulation upon dosing and produced surface intermediates which yeilded two acetylene desorption states at 195 and 175 K. Heating above 300 K to completely desorb the higher temperature state produced new, well-defined LEED Features due to residual surface carbon which disappeared when the surface was heated above 550 K. Clearly, there were distinc changes in the nature of the absorbed layer at 195, 300 and 550 K. These changes were reflected in XPS. For the weakly chemisorbed acetylene a large C(ls) peak at 285.6 eV with a small, broad, indistinc shoulder at higher binding energy (288.2) was observed. The spectrum of the species following acetylene desorption at 275 K, however, showed the formulation of a large C(ls) peak at 283.6 eV in addition to peaks characteristics of the weakly chemisorbed state. This result

  15. Uranium-oxide-based catalysts for the destruction of volatile chloro-organic compounds

    International Nuclear Information System (INIS)

    Hutchings, G.; Heneghan, C.S.; Taylor, S.H.

    1996-01-01

    The industrial release of hydrocarbons and chlorine-containing organic molecules into the environment continues to attract considerable public concern, which in turn has led to governmental attempts to control such emissions. The challenge is to reduce pollution without stifling economic growth. Chlorine-containing pollutants are known to be particularly stable, and at present the main industrial process for their destruction involves thermal oxidation at 1,000 o C, an expensive process that can lead to the formation of highly toxic by-products such as dioxins and dibenzofurans. Catalytic combustion at lower temperatures could potentially destroy pollutants more efficiently (in terms of energy requirements) and without forming toxic by-products. Current industrial catalysts are based on precious metals that are deactivated rapidly by organochlorine compounds. Here we report that catalysts based on uranium oxide efficiently destroy a range of hydrocarbon and chlorine-containing pollutants, and that these catalysts are resistant to deactivation. We show that benzene, toluene, chlorobutane and chlorobenzene can be destroyed at moderate temperatures ( o C) and industrially relevant flow rates. (Author)

  16. Uranium compounds in ceramic enamels-radioactivity analysis and use hazards

    International Nuclear Information System (INIS)

    Cucchi, G.; Amadesi, P.

    1980-01-01

    An analysis was made of the radioactivity of enamel samples, containing depleted Uranium and Uranium ore, such as employed by the ceramic industry to produce paving and lining tiles. An investigation was also made of various types of tiles with depleted Uranium containing enamels, in order to evaluate the use hazard for dwelling houses, in particular in regard to the wear of tiled floors by children as a critical group. The risk to the population due to the use of tiles dyed with enamel containing depleted Uranium was considered an undue risk and as such not permissible. (U.K.)

  17. Measurement methods and optimization of radiation protection: the case of internal exposure by inhalation to natural uranium compounds

    International Nuclear Information System (INIS)

    Degrange, J.P.; Gibert, B.

    1998-01-01

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

  18. Purification of the Drain Water and Distillation Residues from Organic Compounds, Transuranic Elements and Uranium at the Chernobyl NPP

    Directory of Open Access Journals (Sweden)

    Rudenko, L.I.

    2014-05-01

    Full Text Available Article examines the purification of drain water and distillation residue from organic (polymeric compounds, tran suranic elements and uranium. We propose the pretreatment method with the use of a type «Sizol» coagulant-flocculant and catalytic oxidation with hydrogen peroxide and ultrafiltration. This method prevents evaporator coking by dustsuppression and other organic substances, which are vulcanized by heating. Removing alpha-emitting radionuclides increases safety level at the nuclear power plant.

  19. Uranium

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  20. Solubility of airborne uranium compounds at the Fernald Environmental Management Project

    International Nuclear Information System (INIS)

    Heffernan, T.E.; Lodwick, J.C.; Spitz, H.; Neton, J.; Soldano, M.

    2000-01-01

    The in vitro volubility of airborne uranium dusts collected at a former uranium processing facility now undergoing safe shutdown, decontamination and dismantling was evaluated by immersing air filters from high volume samplers in simulated lung fluid and measuring the 238 U in sequential dissolution fractions using specific radiochemical analysis for uranium. X rays and photons from the decay of uranium and thorium remaining on the filter after each dissolution period were also directly measured using a planar germanium detector as a means for rapidly evaluating the volubility of the uranium bearing dusts. Results of these analyses demonstrate that two -distinct types of uranium bearing dusts were collected on the filters depending upon the location of the air samplers. The first material exhibited a dissolution half-time much less than one day and was most likely UO 3 . The dissolution rate of the second material, which was most likely U 3 O 8 , exhibited two components. Approximately one-third of this material dissolved with a halftime much less than one day. The remaining two-thirds of the material dissolved with half times between 230 ± 16 d and 1350 ± 202 d. The dissolution rates for uranium determined by radiochemical analysis and by gamma spectrometry were similar. However, gamma spectrometry analysis suggested a difference between the half times of 238 U and its daughter 234 Th which may have important implications for in vivo monitoring of uranium

  1. Use of electrothermal atomization for determining metallic impurities in nuclearly pure uranium compounds

    International Nuclear Information System (INIS)

    Franco, M.B.

    1986-01-01

    Atomic absorption spectrometry with electrothermal atomization was used for the determination of Al, Cd, Cr, Fe, Mn, Mo and Ni as impurities in uranium oxide samples. The determinations were performed in solubilized samples both with and without uranium separation as well as in solid samples. (Author) [pt

  2. Use of electrothermal atomization for determining metallic impurities in nuclearly pure uranium compounds

    International Nuclear Information System (INIS)

    Franco, M.B.

    1985-01-01

    Atomic absorption spectrometry with electrothermal atomization was used for the determination of Al, Cd, Cr, Fe, Mn, Mo and Ni as impurities in uranium oxide samples. The determinations were performed in solubilized samples both with and without uranium separation as well as in solid samples. (Author) [pt

  3. Metal electrodeposition and electron transfer studies of uranium compounds in room temperature ionic liquids

    International Nuclear Information System (INIS)

    Stoll, M.E.; Oldham, W.J.; Costa, D.A.

    2004-01-01

    Room temperature ionic liquids (RTIL's) comprised of 1,3-dialkylimidazolium or quaternary ammonium cations and one of several anions such as PF 6 - , BF 4 - , or - N(SO 2 CF 3 ) 2 , represent a class of solvents that possess great potential for use in applications employing electrochemical procedures. Part of the intrigue with RTIL's stems from some of their inherent solvent properties including negligible vapor pressure, good conductivity, high chemical and thermal stability, and non-flammability. Additionally, a substantial number of RTIL's can be envisioned simply by combining different cation and anion pairs, thereby making them attractive for specific application needs. We are interested in learning more about the possible use of RTIL's within the nuclear industry. In this regard our research team has been exploring the electron transfer behavior of simple metal ions in addition to coordination and organometallic complexes in these novel solvents. Results from our research have also provided us with insight into the bonding interactions between our current anion of choice, bis(trifluoromethylsulfonyl)imide = NTf 2 , and open coordination sites on actinide and transition metal fragments. This presentation will focus on recent results in two areas: the electrodeposition of electropositive metal ions from RTIL solutions and the electron transfer behavior for several uranium complexes. Details concerning the cathodic electrodeposition and anodic stripping of alkali metals (Na, K) from various working electrode surfaces (Pt, Au, W, Glassy Carbon) will be discussed. Figure 1 displays typical behavior for the electrodeposition of potassium metal from an RTIL containing potassium ions produced through the reaction of KH with H[NTf 2 ]. Our efforts with other metal ions, including our results to date with uranium electrodeposition, will be covered during the presentation. The electron transfer behavior for a number of uranium complexes have been studied with various

  4. The determination of the crystal structures of some uranium compounds by means of x-ray and neutron diffraction

    International Nuclear Information System (INIS)

    Adrian, H.W.W.

    1977-10-01

    In industrial uranium processing or reprocessing procedures, aqueous uranyl nitrate solutions are an intermediate product. The compounds, whose structures are reported, might prove valuable as alternative crystallization products to existing methods of extracting the uranium from solution. The compounds are obtained by the addition of hydroxylammonium to the uranyl nitrate solution and are of the general formula UO 2 (NH 2 0) 2 .xH 2 0, where x can take the values zero, two, three and four. In addition a compound of the formula UO 2 (NH 2 0) 2 .2(NH 2 CH).2H 2 0 was obtained. The UO 2 (NH 2 0) compound crystallized in a monoclinic crystal form. Crystals large enough for neutron diffraction were not obtained. The structure of the UO 2 (NH 2 0) 2 .2H 2 0 could not be solved because only disordered crystalline material was available. The structure of UO 2 (NH 2 0) 2 .3H 2 0 was solved by means of room- and low-temperature neutron diffraction. The unit cell is orthorhombic. The structure of α-UO 2 (NH 2 0) 2 .4H 2 0 was investigated by means of room-temperature x-ray and room- and low-temperature neutron diffraction. The unit cell is triclinic. This compound strongly resembles the trihydrate. The UO 2 (NH 2 0) 2 .2(NH 2 0H).2H 2 0 compound gave crystals large enough for single crystal x-ray but not neutron diffraction. The unit cell is orthorhombic. The characteristic powder patterns (indexed except for the dihydrate compound) of the above compounds are reported [af

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

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  6. Improvements made in the methods of purifying uranium compounds and in the production of uranium metal at the Bouchet plant

    International Nuclear Information System (INIS)

    Decrop, J.; Delange, M.; Holder, J.; Huet, H.; Sauteron, J.; Vertes, P.

    1958-01-01

    We intend to chart the development of the techniques used at the Bouchet plant since the First International Conference held in Geneva in 1955. During that Conference, the methods adopted at that time were described by B. GOLDSCHMIDT and P. VERTES. Generally speaking, the development since that time has been governed by the following factors: 1- Conversion to a mass-production scale: The metal output, which amounted to approximately 10 tons in 1952, practically doubled each year, reaching successive figures of 80 tons in 1955, 160 tons in 1956 and 300 tons in 1957. At this very moment the output capacity of the plant is approaching its maximum, set at 500 tons/year, which it will reach at the end of the year. Beyond this output figure, the work will be carried on by the second French uranium production plant, which is now being erected at Narbonne. 2- Gradual abandoning of ore treatment, resulting from the decentralization of the duties performed by the CEA; The Bouchet Plant had, as a matter of fact, the first French treatment facilities, operating on the basis of 10 to 20 tons of ore per day. This ore, first concentrated at the production site proper by means of physical or physico-chemical methods to at least a 2 per cent uranium content, was sufficiently valuable to warrant quite well the cost involved in shipping it. However, the increase in the production schedules led to the treatment of ores of lower and lower grades, and it became more profitable to proceed with the chemical treating of these low-grade ores at the site after more or less thorough grading and, if necessary, preconcentration. As a result, the Bouchet plant scarcely ever receives uranium ores; on the contrary, the mining companies send their chemical concentrates, uranous phosphate and then sodium uranate from the Gueugnon Works in Saone-et-Loire since 1955; magnesium uranate from the Ecarpiere Works in Vendee since the beginning of 1957 and, very soon, products from the works which are now

  7. Compared biokinetic and biological studies of chronic and acute inhalations of uranium compounds in the rat

    International Nuclear Information System (INIS)

    Monleau, M.

    2005-12-01

    Uranium is a natural, radioactive heavy metal, widely used in the nuclear industry in various chemical and isotopic forms. Its use in the fuel cycle involves the risk of radiological exposure for the workers, mainly via the inhalation of uranium particles. According to the workplace configuration, uranium contaminations can be acute or repeated, involve various chemical forms and different levels of enrichment, as well as involving one or several components. The dosimetric concepts and models available for workers' radiological protection, as well as most of the studies of the biological effects, correspond to acute exposure situations. Moreover the processes leading to pathological effects are little known in vivo. In this context, the main question is to know whether exposures due to repeated inhalation by rats induce the element kinetics and toxicity, which may be different from those observed after an acute exposure. In this study, comparison of the experimental and theoretical biokinetics of an insoluble uranium repeatedly inhaled over three weeks shows that a chronic contamination is correctly modelled, except for bone retention, by the sum of acute, successive and independent incorporations. Moreover, the kinetics of a soluble uranium inhaled irregularly can be modified by previous repeated exposure to an insoluble uranium. In certain cases therefore, exposure to uranium could modify its biokinetics during later exposures. At a toxicological level, the study demonstrates that the uranium particles inhaled repeatedly induce behavioural disruptions and genotoxic effects resulting in various sorts of DNA damage, in several cell types and certainly depending on the quantity inhaled. Exposures involving several uraniferous components produce a synergy effect. Moreover, repeated inhalations worsen the genotoxic effects in comparison to an acute exposure. This work demonstrates the importance of not ignoring the effects of the repetition of uranium exposure. It

  8. Analysis of uranium and of some of its compounds and alloys. Copper spectrophotometric determination

    International Nuclear Information System (INIS)

    Copper determination in uranium, uranium oxides (UO 2 , UO 3 , U 3 O 8 ), ammonium diuranate, U-Al-Fe alloy (700 ppm Al and 300 ppm Fe) and U-Mo alloy (1.1 percent Mo) by acid dissolution reduction of copper by hydroxylamine hydrochloride and formation of a complex with diquinolyle-2,2' amyl alcohol (pH value 6 to 7) and spectrophotometry at 550 nm. The method is applicable for copper content between 5 to 40 ppm in respect of uranium contained in the material [fr

  9. Epidemiological study of workers employed in the French nuclear fuel industry and analysis of the health effects of uranium compounds according to their solubility

    International Nuclear Information System (INIS)

    Zhivin, Sergey

    2015-01-01

    External γ-radiation exposure has been shown to be associated with mortality risk due to leukemia, solid cancer, and, possibly, circulatory diseases (CSD). By contrast, little information is available on health risks following the internal contamination, especially the inhalation of uranium compounds with respect to their physicochemical properties (PCP), such as solubility, isotopic composition and others. The aim of this PhD thesis was to estimate mortality risk of cancer and non-cancer diseases in French nuclear fuel cycle workers and comprises three objectives: (1) evaluation of the impact of uranium on mortality through a critical literature review, (2) analysis of cancer and non-cancer mortality in a cohort of uranium enrichment workers, (3) analysis of the relationship between CSD mortality and internal uranium dose in AREVA NC Pierrelatte workers. Existing epidemiological data on uranium PCP and associated health outcomes are scarce. Studies of nuclear fuel cycle workers by sub-groups within the specific stage of the cycle (e.g., uranium enrichment and fuel fabrication) are considered the most promising to shed light on the possible associations, given that such sub-groups present the advantage of a more homogenous uranium exposure. To study the mortality risk associated with exposure to rapidly soluble uranium compounds, we set up a cohort of 4,688 uranium enrichment workers with follow-up between 1968 and 2008. Individual annual exposure to uranium, external γ-radiation, and other non-radiological hazards (trichloroethylene, heat, and noise) were reconstructed from job-exposure matrixes (JEM) and dosimetry records. Over the follow-up period, 131,161 person-years at risk were accrued and 21% of the subjects had die. Analysis of Standardized Mortality Ratios (SMR) showed a strong healthy worker effect (SMR all deaths 0.69, 95% confidence intervals (CI) 0.65 to 0.74; n=1,010). Exposures to uranium and external γ-radiation were not significantly associated

  10. Acute and chronic toxicity of uranium compounds to Ceriodaphnia-Daphnia dubia

    International Nuclear Information System (INIS)

    Pickett, J.B.; Specht, W.L.; Keyes, J.L.

    1993-01-01

    A study to determine the acute and chronic toxicity of uranyl nitrate, hydrogen uranyl phosphate, and uranium dioxide to the organism Ceriodaphnia dubia was conducted. The toxicity tests were conducted by two independent environmental consulting laboratories. Part of the emphasis for this determination was based on concerns expressed by SCDHEC, which was concerned that a safety factor of 100 must be applied to the previous 1986 acute toxicity result of 0.22 mg/L for Daphnia pulex, This would have resulted in the LETF release limits being based on an instream concentration of 0.0022 mg/L uranium. The NPDES Permit renewal application to SCDHEC utilized the results of this study and recommended that the LETF release limit for uranium be based an instream concentration of 0.004 mg/L uranium. This is based on the fact that the uranium releases from the M-Area LETF will be in the hydrogen uranyl phosphate form, or a uranyl phosphate complex at the pH (6--10) of the Liquid Effluent Treatment Facility effluent stream, and at the pH of the receiving stream (5.5 to 7.0). Based on the chronic toxicity of hydrogen uranyl phosphate, a lower uranium concentration limit for the Liquid Effluent Treatment Facility outfall vs. the existing NPDES permit was recommended: The current NPDES permit ''Guideline'' for uranium at outfall M-004 is 0.500 mg/L average and 1.0 mg/L maximum, at a design flowrate of 60 gpm. It was recommended that the uranium concentration at the M-004 outfall be reduced to 0.28 mg/L average, and 0.56 mg/L, maximum, and to reduce the design flowrate to 30 gpm. The 0.28 mg/L concentration will provide an instream concentration of 0.004 mg/L uranium. The 0.28 mg/L concentration at M-004 is based on the combined flows from A-014, A-015, and A-011 outfalls (since 1985) of 1840 gpm (2.65 MGD) and was the flow rate which was utilized in the 1988 NPDES permit renewal application

  11. Study on the applicability of structural and morphological parameters of selected uranium compounds for nuclear forensic purposes

    Energy Technology Data Exchange (ETDEWEB)

    Ho Mer Lin, Doris

    2015-03-13

    Nuclear forensic science or nuclear forensics, is a relatively young discipline which evolved due to the need of analysing interdicted nuclear or radioactive material, necessary for determining its origin. Fundamentally, nuclear forensic science makes use of measurable material properties, referred to as ''signatures'', which provide hints on the history of the material. As part of the advancement in this multi-faceted field, new signatures are constantly sought after and as well as analytical techniques to efficiently and accurately determine the signatures. The work carried out in this study is part of this fulfilment to investigate new structural and morphological parameters as possible new nuclear forensic signatures for selected uranium compounds. The scientific goals have been oriented into three parts for investigations in this study. Firstly, five different compositions of uranium ore concentrates (UOCs) were prepared in the laboratory under well-defined conditions. These materials were subsequently characterized by several techniques such as X-ray diffraction, thermogravimetry/differential thermal analysis, Infrared and Raman spectroscopy, mass spectrometry, scanning electron microscopy etc. Such materials were pivotal for comparison with the industrial samples. Secondly, several uranium compounds, mainly UOCs were measured using Raman spectroscopy. At least three different Raman spectrometers were used and a comparison made in their performance and suitability for nuclear forensics. Raman spectra of industrial uranium materials were interpreted with regard to compound identification and to determination of (anionic) impurities. Anionic impurities that were present were identified and they could provide clues to the processing history of the samples. Statistical techniques such as principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) were applied to several Raman spectra. The analysis showed that

  12. Study on the applicability of structural and morphological parameters of selected uranium compounds for nuclear forensic purposes

    International Nuclear Information System (INIS)

    Ho Mer Lin, Doris

    2015-01-01

    Nuclear forensic science or nuclear forensics, is a relatively young discipline which evolved due to the need of analysing interdicted nuclear or radioactive material, necessary for determining its origin. Fundamentally, nuclear forensic science makes use of measurable material properties, referred to as ''signatures'', which provide hints on the history of the material. As part of the advancement in this multi-faceted field, new signatures are constantly sought after and as well as analytical techniques to efficiently and accurately determine the signatures. The work carried out in this study is part of this fulfilment to investigate new structural and morphological parameters as possible new nuclear forensic signatures for selected uranium compounds. The scientific goals have been oriented into three parts for investigations in this study. Firstly, five different compositions of uranium ore concentrates (UOCs) were prepared in the laboratory under well-defined conditions. These materials were subsequently characterized by several techniques such as X-ray diffraction, thermogravimetry/differential thermal analysis, Infrared and Raman spectroscopy, mass spectrometry, scanning electron microscopy etc. Such materials were pivotal for comparison with the industrial samples. Secondly, several uranium compounds, mainly UOCs were measured using Raman spectroscopy. At least three different Raman spectrometers were used and a comparison made in their performance and suitability for nuclear forensics. Raman spectra of industrial uranium materials were interpreted with regard to compound identification and to determination of (anionic) impurities. Anionic impurities that were present were identified and they could provide clues to the processing history of the samples. Statistical techniques such as principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) were applied to several Raman spectra. The analysis showed that

  13. Uranium recovery from phosphate fertilizer in the form of a high purity compound

    International Nuclear Information System (INIS)

    Bunus, F.; Coroianu, T.; Filip, G.; Filip, D.

    2001-01-01

    Uranium recovery from phosphate fertilizer industry is based on a one cycle extraction-stripping process. The process was experimented on both sulfuric and nitric acid attack of phosphate rock when uranium is dissolved in phosphoric acid (WPA) or phosphonitric (PN) solution respectively. The WPA and PN solution must be clarified. In the first alternative by ageing and settling and in the second by settling in the presence of flocculant. The organic components must be removed on active carbon for WPA only since in the case of nitric attack calcined phosphates are used. In both alternatives uranium is extracted from aqueous acidic solutions in the same time with the rare earths (REE), by di(2-ethylhexyl) phosphate (DEPA) as basic extractants, eventually in the presence of octylphosphine oxide (TOPO) as synergic agent. The stripping process is carried out in two stages: in the first stage REE are stripped and precipitated by HF or NH 4 F + H 2 S0 4 and in the second stage uranium as U(VI) is stripped by the same reagents but in the presence of Fe(II) as reductant for U(VI) to U(IV) inextractible species. Tetravalent uranium is also precipitated as green cake either UF 4 xH 2 0 or (NH 4 ) 7 U 6 F 31 as dependent on reagents HF or NH 4 F + H 2 S0 4 . Uranium stripping is possible for PN solution only if HNO 3 partially extracted is previously washed out by a urea solution. The green cake washed and filtered is dissolved in nitric acid in presence of Al(OH)3 as complexant for F. The filtered nitric solution is adjusted to 3-5 mol/L HNO 3 and extracted by 20% TBP when uranium is transferred to the organic phase which after scrubbing is stripped in the classic way with acidulated (HN0 3 ) demineralized water. Uranium is precipitated as diuranate of high purity. Rare earths left in the aqueous raffinate are extracted by pure TBP from 8-10 mol/L HNO 3 medium. The stripping process takes place with acidulated water. Rare earths are precipitated as hydroxides. (author)

  14. Synthesis and characterization of nanometer sized thermoelectric lead-antimony-silver-tellurium compounds and related materials

    International Nuclear Information System (INIS)

    Petri, Denis

    2012-01-01

    The present dissertation deals with different variants of synthesis and processing of nanocrystalline composites of various thermoelectric compounds based on lead telluride including LAST-m (AgPb m SbTe m+2 ), LASTT-m-x (AgPb m-x Sn x SbTe m+2 ), LABST-m-x (AgPb m Sb 1-x Bi x Te m+2 ), doped LAST-m and (PbTe) m (M 15 2 Te 3 ) and the characterization thereof. A new route of manufacturing nanocrystalline composites was developed. The so called co-ball milling-route includes the synthesis of bi- or multinary compounds by conventional solid state melting methods followed by combined milling of appropriate amounts in a planetary ball mill; a process related to the widely used mechanical alloying of elemental powders. The as produced powders were shortly annealed for one hour and a.erwards compacted either at room temperature followed by pressureless sintering or combined application of high pressure and elevated temperatures via spark-plasma-sintering or short-term-sintering. The ball milling yielded micron-sized agglomerates consisting of crystallites with diameters ranging from 10 to 50 nm. These crystallites exhibited complicated internal nanostructures severe crystal defects as a consequence of the high energy processing. During short-term annealing some grain coarsening occured and the crystal defects partly healed, which was confirmed by TEM and HRTEM investigations as well as profile analysis of XRD powder pattern. Local EDX-analysis showed different compositions at every point as a consequence of synthesis and decomposition of the compounds. Measurements of thermopower, electrical and thermal conductivity were carried out and the values of the figure of merit ZT and the powerfactor were calculated. In general the compounds exhibited larger thermopower than corresponding bulk materials, which might be attributed to energy filtering of charge carriers at partly oxidized grain boundaries. Due to enhanced phonon scattering at grain boundarys, nanoscopic

  15. Enhanced tracheostomy wound healing using maltodextrin and silver alginate compounds in pediatrics: a pilot study.

    Science.gov (United States)

    Hartzell, Larry D; Havens, Tara N; Odom, Brian H; Stillman, Tanya G; Boswell, Jessica L; Bower, Charles M; Richter, Gresham T

    2014-12-01

    Tracheostomy wounds are commonly encountered in children but rarely reported. Relatively few treatments are available or have been investigated to manage this problem. Healing times for pediatric tracheostomy wounds are often unpredictable and protracted. Recent use of maltodextrin gel (MD) and a silver alginate sponge (AG) at our institution has demonstrated expedited healing and interest in this novel treatment for tracheostomy wounds. We conducted an 11-month retrospective review of children with wound complications following tracheostomy placement at a tertiary care facility. Wounds were evaluated and rated based upon the National Pressure Ulcer Advisory Panel staging system. Subjects identified with stage 2 or greater tracheostomy-related ulcers treated with MD and/or AG were included. Subject characteristics and wound healing rates were tabulated in a database that included age, wound site, initial and final wound stage, type of treatment, length of treatment, and complications. Tracheostomy wounds treated as an out-patient were excluded from the study. Eighteen subjects, which included both in-patients and out-patients, were treated with AG and/or MD during the study period for tracheostomy-related wounds. Of the 26 subjects with tracheostomies performed during the study period, 10 (38.5%) were treated for postoperative wounds. A total of 11 subjects completed their in-patient wound treatment and were thus included in the study. Average subject age was 5.3 y (range 0.25-15.6 y). Wound locations were as follows: infrastomal region (n = 8), stoma (n = 2), and lateral neck (n = 1). Six subjects had stage 2 wounds, 4 had stage 3 wounds, and 1 had a stage 4 ulcer. All wounds achieved complete epithelialization following treatment with MD and/or AG. The average length of treatment was 12.8 d (range 6-28 d). No adverse effects were identified. Postoperative tracheostomy wounds are common. The use of MD and AG provides an effective and safe treatment for

  16. Magnetic anisotropy in intermetallic compounds containing both uranium and 3d-metal

    Czech Academy of Sciences Publication Activity Database

    Andreev, Alexander V.; Tereshina, Evgeniya; Gorbunov, Denis; Šantavá, Eva; Šebek, Josef; Žáček, Martin; Homma, Y.; Shiokawa, Y.; Satoh, I.; Yamamura, Y.; Komatsubara, T.; Watanabe, K.; Koyama, K.

    2013-01-01

    Roč. 114, č. 9 (2013), s. 727-733 ISSN 0031-918X R&D Projects: GA ČR GAP204/12/0150 Institutional support: RVO:68378271 Keywords : uranium intermetallics * magnetic anisotropy * ferromagnetism Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.605, year: 2013

  17. Determination of trace lithium in uranium compounds by adsorption on activated alumina using a micro-column method.

    Science.gov (United States)

    Luo, Ming-Biao; Li, Bo-Ping; Yang, Zhi; Liu, Wei; Sun, Yu-Zhen

    2008-08-01

    A novel method using a micro-column packed with active alumina as solid phase was proposed for separation of trace lithium from uranium compounds prior to determination. The method is based on a preliminary chromatographic separation of the total amount of uranium. This separation involves passing the solution containing sodium carbonate through active alumina and then eluting the trace lithium retained by the solid phase with a solution of sulfuric acid. Two modes, off-line and on-line micro-column preconcentration, were performed. In conjunction with atomic absorption spectrometry, this on-line preconcentration technique allows a determination of lithium at 10(-9) level. Both off-line and on-line mode operation conditions were investigated in separation and determination of trace lithium by micro-column method (length of column bed, flow rate, etc.). The adsorption capacity of activated alumina was found to be 343 microg g(-1) for lithium. Under the optimal operation condition, the detection limit (DL) of on-line preconcentration corresponding to three times the standard deviation of the blank (S/N = 3) was found to be 1.3 ng mL(-1) and the RSD of this method is 3.32% (n = 5). The on-line calibration graph was linear over the range 20 - 200 ng mL(-1). A good preconcentration factor 820 was achieved by experiment under the on-line mode. The developed method was applied to the analysis of trace lithium in nuclear grade uranium compounds.

  18. Kinetic study of the fluorination by fluorine of some uranium and plutonium compounds; Etude cinetique de la fluoration par le fluor de quelques composes de l'uranium et du plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Vandenbussche, G [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-12-15

    The study of fluorination reactions of uranium and plutonium compounds with elementary fluorine, has been carried out using a thermogravimetric method. These reactions are heterogeneous ones, and of the following type: S(solid) + G{sub 1}(gas) - G{sub 2}(gas). The kinetics of these reactions correspond to a uniform attack of the entire surface of the sample. {alpha}: being the degree of completion of the reaction, k(rel): being the relative rate of penetration of the reaction interface, t: being the time, one have the relation: (1-{alpha}){sup 1/3} = 1 - k(rel)*t. The mechanism of the reaction varies according to the nature of the compound: 1) with uranium tetrafluoride and plutonium tetrafluoride, the reaction proceeds in a single step; 2) with uranium oxides, the reaction proceeds in two steps, uranium oxyfluoride being the intermediate compound; 3) with plutonium oxide, the reaction proceeds in two steps, plutonium tetrafluoride being the intermediate compound; and 4) with uranium trichloride, the mechanism is complex: chlorine trifluoride is formed. (author) [French] L'etude des reactions de fluoration par le fluor, de composes de l'uranium et du plutonium a ete faite par thermogravimetrie. Ce sont des reactions heterogenes du type: S(solide) + G{sub 1}(gaz) - G{sub 2}(gaz). La cinetique de ces reactions est celle correspondant a une attaque uniforme de toute la surface de l'echantillon. Si {alpha}: est le degre d'avancement de la reaction, k(rel): est la vitesse relative d'avancement d'un interface reactionnel, t: le temps. On a la relation: (1-{alpha}){sup 1/3} = 1-k(rel)*t. Le mecanisme de la reaction varie selon la nature du compose: 1) tetrafluorure d'uranium et tetrafluorure de plutonium, la reaction s'effectue en un seul stade; 2) Oxydes d'uranium: la reaction s'effectue en deux stades, l'oxyfluorure d'uranium est le compose intermediaire; 3) oxyde de plutonium, la reaction s'effectue en deux stades, la tetrafluorure de plutonium est le compose

  19. Chemical shift of U L3 edges in different uranium compounds obtained by X-ray absorption spectroscopy with synchrotron radiation

    International Nuclear Information System (INIS)

    Joseph, D.; Jha, S.N.; Nayak, C.; Bhattacharyya, D.; Babu, P. Venu

    2014-01-01

    Uranium L 3 X-ray absorption edge was measured in various compounds containing uranium in U 4+ , U 5+ and U 5+ oxidation states. The measurements have been carried out at the Energy Dispersive EXAFS beamline (BL-08) at INDUS-2 synchrotron radiation source at RRCAT, Indore. Energy shifts of ∼ 2-3 eV were observed for U L 3 edge in the U-compounds compared to their value in elemental U. The different chemical shifts observed for the compounds having the same oxidation state of the cation but different anions or ligands show the effect of different chemical environments surrounding the cations in determining their X-ray absorption edges in the above compounds. The above chemical effect has been quantitatively described by determining the effective charges on U cation in the above compounds. (author)

  20. Fluorinated compounds in the uranium conversion process: risk analysis and proposition of pictograms

    International Nuclear Information System (INIS)

    Jeronimo, Adroaldo Clovis; Oliveira, Wagner dos Santos

    2012-01-01

    In the process of uranium hexafluoride production there are risks that must be taken into account since the time of completing the project chemist, in its conceptual stage, until to the stage of detailed design and are associated with the handling of chemicals, especially fluoride hydrogen and fluorine. This paper aims to address issues related to the prevention of risks related to industrial safety and health and the environment, considering the different stages of the uranium conversion. Take into account the safety warnings of the plant and, accordingly, make the proposition of pictograms adequate to alert operators of care to be taken during the proposition of pictograms adequate to alert operators of care to be taken during the conduct of these chemical processes. (author)

  1. Plasmachemical synthesis and evaluation of the thermal conductivity of metal-oxide compounds "Molybdenum-uranium dioxide"

    Science.gov (United States)

    Kotelnikova, Alexandra A.; Karengin, Alexander G.; Mendoza, Orlando

    2018-03-01

    The article represents possibility to apply oxidative and reducing plasma for plasma-chemical synthesis of metal-oxide compounds «Mo‒UO2» from water-salt mixtures «molybdic acid‒uranyl nitrate» and «molybdic acid‒ uranyl acetate». The composition of water-salt mixture was calculated and the conditions ensuring plasma-chemical synthesis of «Mo‒UO2» compounds were determined. Calculations were carried out at atmospheric pressure over a wide range of temperatures (300-4000 K), with the use of various plasma coolants (air, hydrogen). The heat conductivity coefficients of metal-oxide compounds «Mo‒UO2» consisting of continuous component (molybdenum matrix) are calculated. Inclusions from ceramics in the form of uranium dioxide were ordered in the matrix. Particular attention is paid to methods for calculating the coefficients of thermal conductivity of these compounds with the use of different models. Calculated results were compared with the experimental data.

  2. Ferromagnetic quantum criticality in the uranium-based ternary compounds URhSi, URhAl, and UCoAl

    International Nuclear Information System (INIS)

    Combier, Tristan

    2014-01-01

    In this thesis we explore the ferromagnetic quantum criticality in three uranium-based ternary compounds, by means of thermodynamical and transport measurements on single crystal samples, at low temperature and high pressure. URhSi and URhAl are itinerant ferromagnets, while UCoAl is a paramagnet being close to a ferromagnetic instability. All of them have Ising-type magnetic ordering. In the orthorhombic compound URhSi, we show that the Curie temperature decreases upon applying a magnetic field perpendicular to the easy magnetization axis, and a quantum phase transition is expected around 40 T. In the hexagonal system URhAl, we establish the pressure-temperature phase diagram for the first time, indicating a quantum phase transition around 5 GPa. In the isostructural compound UCoAl, we investigate the metamagnetic transition with measurements of magnetization, Hall effect, resistivity and X-ray magnetic circular dichroism. Some intriguing magnetic relaxation phenomena are observed, with step-like features. Hall effect and resistivity have been measured at dilution temperatures, under hydrostatic pressure up to 2.2 GPa and magnetic field up to 16 T. The metamagnetic transition terminates under pressure and magnetic field at a quantum critical endpoint. In this region, a strong effective mass enhancement occurs, and an intriguing difference between up and down field sweeps appears in transverse resistivity. This may be the signature of a new phase, supposedly linked to the relaxation phenomena observed in magnetic measurements, arising from frustration on the quasi-Kagome lattice of uranium atoms in this crystal structure. (author) [fr

  3. Review of experience gained in fabricating nuclear grade uranium and thorium compounds and their analytical quality control at the Instituto de Energia Atomica, Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Abrao, A.; Franca, J.M. Jr.; Ikuta, A.; Pueschel, C.R.; Federgruen, L.; Lordello, A.R.; Tomida, E.K.; Moraes, S.; Brito, J. de; Gomes, R.P.; Araujo, J.A.; Floh, B.; Matsuda, H.T.

    1977-01-01

    This paper summarizes the main activities dealing with the fabrication of nuclear grade uranium and thorium compounds at the Instituto de Energia Atomica, Sao Paulo. Identification of problems and their resolutions, the experience gained in plant operation, the performance characteristics of an ion-exchange facility and a solvent extraction unit (a demonstration plant based on pulsed columns for purification of uranium and production of ammonium diuranate) are described. A moving-bed facility for UF 4 preparation and its operation is discussed. A pilot plant for uranium and thorium oxide microsphere preparation based on internal gelation for HTGR fuel type is also described. A solvent extraction pilot plant for thorium purification based on a compound extraction-scrubbing column and a mixer-settler battery and the involved technology for thorium purification are commented. The main products, namely ammonium diuranate, uranyl amonium tricarbonate, uranium trioxide, uranium tetrafluoride, thorium nitrate and thorium oxalate and their quality are commented. The development of necessary analytical procedures for the quality control of the mentioned nuclear grade products is summarized. A great majority of such procedures was particularly suitable for analyzing traces impurities. Designed for installation are the units for denitration of uranyl nitrate solutions and pilot plants for elemental fluorine and UF 6 . The installation of a laboratory-scale plant designed for reprocessing irradiated uranium and an experimental unit for the recovery of protactinium from irradiated thorium is in progress

  4. Chronic exposure to uranium compounds: medical surveillance problems related to their physico-chemical properties and their solubility: actual data and future prospects

    International Nuclear Information System (INIS)

    Ansoborlo, E.; Chalabreysse, J.C.

    1988-01-01

    A method was developped to assess uranium exposure hazards at work stations based on industrial experience acquired in Comurhex Malvesi at Narbonne. Applied to uranium tetrafluoride (UF4), the method involves five steps: 1/ Characterization of the industrial compound, including physico-chemical properties (density, surface area, X-ray spectrum and uranium enrichment). 2/ In vitro biological solubility with different synthetic fluids like Gamble solution added with differents gaz or compounds (Oxygen or hydrogen peroxyde), in order to determine the solubility class D, W or Y. 3/ Assessment of work station concentration in Bq m -3 and particle size distribution (AMAD). 4/ Monitoring workers by routine urinary excretion completed, if necessary, by fecal excretion and γ spectrometry. 5/ Use of individual protection filters or masks. Results and actual data on UF4 are presented and future prospects of studies on calcinated uranates are dealed with [fr

  5. Stoichiometry of the U3O8 phase formed during calcination of some uranium compounds

    International Nuclear Information System (INIS)

    El-Fekey, S.A.; Farah, M.Y.; Rofail, N.H.

    1981-01-01

    Although recent work has shown U 3 O 8 phase to be the decomposition product obtained after calcining uranyl nitrate, sulphate or ammonium uranate, neither the necessary conditions for obtaining stoichiometric U 3 O 8 nor the details of the reaction have been established. Presence of sulphate or nitrate ions during preparation greatly affects the O/U of the obtained oxides and the physico-chemical properties of uranium tetrafluoride prepared afterwards from it (1-3). The aim of the present investigation was to study the effect of calcination regimes on the stoichiometry of the U 3 O 8 phase produced by the thermal decomposition of uranyl nitrate, sulphate, and ammonium uranate, which was prepared by precipitation from nuclear-pure uranyl sulphate. Stoichiometry of the U 3 O 8 phase formed during calcination of ammonium uranate precipitated from nuclear pure uranyl nitrate solution was reported before (1)

  6. Red blood cells sensitivity to oxidative stress in the presence of low concentrations of uranium compound

    Energy Technology Data Exchange (ETDEWEB)

    Shevchenko, O.G. [Institute of Biology, Komi Scientific Centre, Ural Branch of Russian Academy of Sciences, 167982, Syktyvkar (Russian Federation)

    2014-07-01

    Uranium is a natural radioactive element widespread in biosphere. There are a few works that examined cellular and molecular mechanisms of uranium toxicity. Red blood cells are classical model to investigate toxicity mechanisms on cell membrane system. The aim of present work is to study the effect of uranyl ion in nano-molar concentrations on erythrocytes sensitivity (in vitro) to factors provoking acute oxidative stress. Uranyl ions were added to suspension of mice red blood cells in PBS as UO{sub 2}Cl{sub 2} solution. Samples were incubated in a thermostatic shaker at 37 deg. C during 3-5 hours. Than acute oxidative stress was induced by H{sub 2}O{sub 2} (0.9 mM) or AAPH (5 mM) solutions. Destabilization of the membrane was induced by nonionic detergent Triton X-100. The hemolysis degree and the content of LPO secondary products reacting with 2-thiobarbituric acid in the incubation mixture were determined spectrophotometrically. The ratio of hemoglobin various forms (oxyHb, metHb and ferrylHb) was calculated taking into account extinction coefficients. It was shown that uranyl chloride enhances cell sensitivity to nonionic detergent Triton X-100 effects, indicating alterations of membrane acyl chain order due to contact with the radionuclide ions. Uranium exposure also caused an increase in the cell sensitivity to the AAPH effects, resulted in a decrease in red cell survival rate, a sharp increase in accumulation of hemoglobin oxidation products and a slight increase in the concentration of LPO secondary products. Thus, uranyl ions change physicochemical properties of the erythrocyte membranes that resulted in increased sensitivity to effects of peroxyl radicals formed by thermal decomposition of AAPH. On the contrary, use of another source of free radicals - H{sub 2}O{sub 2} - after uranyl ions exposure resulted in marked decrease of oxidative hemolysis, inhibition of LPO and hemoglobin oxidation. Since the uranium chemical properties similar to properties of

  7. High loading uranium plate

    International Nuclear Information System (INIS)

    Wiencek, T.C.; Domagala, R.F.; Thresh, H.R.

    1990-01-01

    Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pari of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat hiving a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process

  8. Copper and silver halates

    CERN Document Server

    Woolley, EM; Salomon, M

    2013-01-01

    Copper and Silver Halates is the third in a series of four volumes on inorganic metal halates. This volume presents critical evaluations and compilations for halate solubilities of the Group II metals. The solubility data included in this volume are those for the five compounds, copper chlorate and iodate, and silver chlorate, bromate and iodate.

  9. Agricola and the Wismut company: A historical review from the days of silver mining to those of uranium mining in the Erzgebirge. Reflections in view of the 500th return of the birthday of Georg Pawer, who named himself Agricola

    International Nuclear Information System (INIS)

    Schiffner, W.

    1994-01-01

    On the occasion of the 500th return of the birthday of Georgius Agricola (1494-1555) the author, drawing on his own experience from decades of work in bismuth/uranium mining, celebrates this great Saxonian humanist, whose achievements influence even modern-day mining. The book spans the period of history from silver mining in the Saxonian Ore Mountains during Agricola's time to the period more than 400 years later when uranium was extracted at an unparalleled scale. As substantiated by the historical comparison, Agricola's mining science, the mining technology for which he laid the basis, were still applied even centuries later in bismuth mining. At the same time the book offers a critical review of the last great mining activities in the area, so momentous to man and the environment. (orig./HP) [de

  10. X-ray absorption experiments on rare earth and uranium compounds under high pressure

    International Nuclear Information System (INIS)

    Schmiester, G.

    1987-01-01

    After an introduction into the phenomenon of the mixed valency and the method of measuring the microstructures by X-ray absorption spectroscopy in the area of the L edges under pressure, the results of investigations at selected substitutes of the chalcogenides and puictides of the rare earths and the uranium were given. Thus, pressure-induced valency transitions in YbS and YbTe, instabilities in valency and structural phase transitions in EUS and SmTe as well as the change in the electron structure in USb under pressure were investigated in order to answer questions of solid state physics (e.g. semiconductor-metal transitions, correlation between valency and structural phase transitions). Hybridization effects in L III spectra of formally tetravalent Ca are analyzed at CeF 4 and CeO 2 (insulators) and the role of final state effects in the L III spectra are analyzed at EuP 2 P 2 and TmSe-TmTe (semiconductor systems). (RB) [de

  11. Uranium conversion; Urankonvertering

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-03-15

    FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF{sub 6} and UF{sub 4} are present require equipment that is made of corrosion resistant material.

  12. URANIUM LEACHING AND RECOVERY PROCESS

    Science.gov (United States)

    McClaine, L.A.

    1959-08-18

    A process is described for recovering uranium from carbonate leach solutions by precipitating uranium as a mixed oxidation state compound. Uranium is recovered by adding a quadrivalent uranium carbon;te solution to the carbonate solution, adjusting the pH to 13 or greater, and precipitating the uranium as a filterable mixed oxidation state compound. In the event vanadium occurs with the uranium, the vanadium is unaffected by the uranium precipitation step and remains in the carbonate solution. The uranium-free solution is electrolyzed in the cathode compartment of a mercury cathode diaphragm cell to reduce and precipitate the vanadium.

  13. Synthesis and characterisation of thorium and uranium cyanoacetates and their coordination compounds (Preprint No. AL.14)

    International Nuclear Information System (INIS)

    Deshpande, S.G.; Vaidya, M.A.; Jain, S.C.

    1989-01-01

    Tetracyanoacetates, M(NCCH 2 COO) 4 (where M=Th or U) and UO 2 (NCCH 2 COO) 2 .H 2 O and their coordination complexes with (CH 3 ) 2 S=0 (DMSO), HCOON(CH 3 ) 2 , (DMF), 1,10-Phenenthrolene (Phen) and 2,2'Bipyridine (Bipy), have been synthesised and characterised by elemental analysis, molecular weight determination, molar conductance measurements, X-ray diffraction and infrared (IR) spectroscopic studies (4000 - 200 cm -1 ). Thermogravimetric analysis of the compounds have been carried out to study the thermal decomposition mode. (author)

  14. Crystal field and site deformation in spinels and pentavalent uranium compounds

    International Nuclear Information System (INIS)

    Drifford, M.; Soulie, E.

    1976-01-01

    Magnesium aluminates with different alumina contents have the spinel structure. The optical absorption spectra of doped spinel compounds (Cr 3+ , Ni 2+ , Co 2+ ) or E.S.R. spectra (Cr 3+ , Mn 2+ ) are used for the investigation of the position of the doping materials and the deformation of the crystal sites, and give information on the structural disorders. The local structural information given by the doping materials are compared with the mean structure parameters obtained from X-ray diffraction. The optical absorption spectrum and the principal components of the g tensor for UF 6 Cs and the thermal variation in the magnetic susceptibility for UF 8 Cs 3 and UF 8 (NH 4 ) are used for determining the parameters of the electron Hamiltonian for the f 1 configuration. A rather significant covalent aspect is evidenced for UF 6 Cs, in the framework of the model of Eisenstein and Pryce, this property being weaker for the other two complex compounds. The three parameters giving the crystal field at a deformed cubic site with Dsub(3d) symmetry in the Newman superposition model are noticeably weaker for the 8-coordination than for the 6-coordination. As for UF 8 Cs 3 and UF 8 (NH 4 ) 3 a calculation predicts an electronic levels with a very low excitation, at about 110 and 70cm -1 respectively [fr

  15. Study of thermal decomposition and characterization of uranium compounds by thermogravimetry and differential calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Dantas, J M; Abrao, A [Instituto de Pesquisas Energeticas e Nucleares, Sao Paulo (Brazil). Centro de Engenharia Quimica

    1980-01-01

    The thermal behaviour of different types of ammonium diuranates, produced in the pilot plants of Instituto de Pesquisas Energeticas e Nucleares (Sao Paulo, Brazil), is studied. It was observed that: the contents of absorption and crystallization waters, as well as the content of absorption ammonia vary as a function of drying conditions; the contents of occluded ammonium nitrate vary according to the washing step; ammonia contents vary as a function of pH and of the original solution - greater ammonia concentrations are observed when diuranates are precipitate in uranyl nitrate solutions at higher pH's (9.0). Thermal instability of the intermediate compound varies as a function of the type of the occluded ion, NO/sup -//sub 3/ or SO sup(=)/sub 4/. The thermoanalytical curves show that the diuranates obtained by continuous precipitation have a more reproducible chemical composition than those obtained by batch precipitation.

  16. Systematic study of the lattice dynamics of the uranium rocksalt-structure compounds

    International Nuclear Information System (INIS)

    Jackman, J.A.; Holden, T.M.; Buyers, W.J.L.; DuPlessis, P. de V.; Vogt, O.; Genossar, J.

    1986-01-01

    The phonon-dispersion relations of USe and UTe have been determined by the inelastic scattering of thermal neutrons. All existing phonon measurements for the UX series, viz., UC, UN, UAs, USb, US, USe, and UTe, have been fitted to the rigid-ion and shell models and dispersion relations have been predicted for UP. The U-X force constants dominate the lattice dynamics and are nearly constant for the series, whereas the U-U force constants vary systematically from being large and positive for the compounds with the smallest lattice parameter to being negative for the chalcogenide series. The negative U-U force constant is identified with destabilizing f-d interactions. Elastic constants, derived from the slopes of the dispersion relations and from ultrasound velocity measurements, have been determined. The bulk modulus decreases unusually rapidly as the lattice parameter increases and is in fair agreement with band-structure calculations

  17. NMR shielding calculations across the periodic table: diamagnetic uranium compounds. 2. Ligand and metal NMR.

    Science.gov (United States)

    Schreckenbach, Georg

    2002-12-16

    In this and a previous article (J. Phys. Chem. A 2000, 104, 8244), the range of application for relativistic density functional theory (DFT) is extended to the calculation of nuclear magnetic resonance (NMR) shieldings and chemical shifts in diamagnetic actinide compounds. Two relativistic DFT methods are used, ZORA ("zeroth-order regular approximation") and the quasirelativistic (QR) method. In the given second paper, NMR shieldings and chemical shifts are calculated and discussed for a wide range of compounds. The molecules studied comprise uranyl complexes, [UO(2)L(n)](+/-)(q); UF(6); inorganic UF(6) derivatives, UF(6-n)Cl(n), n = 0-6; and organometallic UF(6) derivatives, UF(6-n)(OCH(3))(n), n = 0-5. Uranyl complexes include [UO(2)F(4)](2-), [UO(2)Cl(4)](2-), [UO(2)(OH)(4)](2-), [UO(2)(CO(3))(3)](4-), and [UO(2)(H(2)O)(5)](2+). For the ligand NMR, moderate (e.g., (19)F NMR chemical shifts in UF(6-n)Cl(n)) to excellent agreement [e.g., (19)F chemical shift tensor in UF(6) or (1)H NMR in UF(6-n)(OCH(3))(n)] has been found between theory and experiment. The methods have been used to calculate the experimentally unknown (235)U NMR chemical shifts. A large chemical shift range of at least 21,000 ppm has been predicted for the (235)U nucleus. ZORA spin-orbit appears to be the most accurate method for predicting actinide metal chemical shifts. Trends in the (235)U NMR chemical shifts of UF(6-n)L(n) molecules are analyzed and explained in terms of the calculated electronic structure. It is argued that the energy separation and interaction between occupied and virtual orbitals with f-character are the determining factors.

  18. The possibility of the mixed valence state in the uranium intermetallic compounds: UCoGa5, U2Ru2Sn and U2RuGa8

    International Nuclear Information System (INIS)

    Troc, Robert

    2007-01-01

    The mixed valence (MV) phenomenon has been observed so far in a large number of various compounds but containing only lanthanides. These properties are usually associated with the mixing of the localised f-state and the band states. The usual valence state for magnetic uranium intermetallics is the trivalent state 5f 3 or hybridised 5f 2 6d 1 , both are nearly degenerate in energy and can compete for a stability of the compound. In some cases a gain in an energy minimum may be achieved by very fast fluctuating between these two states with a time of 10 -14 s, which does not allow to yield the ordered state even if the exchange interactions (favourite the U-U distances) would be able for that. The latter cases seem to concern the described here intermetallics: one ternary compound based on Co, UCoGa 5 , and the two uranium ternary compounds based on Ru, namely U 2 Ru 2 Sn and U 2 RuGa 8 which all crystallize in a tetragonal unit cell. All these compounds show a maximum in their temperature dependences of the magnetic susceptibility measured along and perpendicular to the c-axis. Such a behaviour, which is reminiscent of a number of Ce (Sm, Eu) and Yb compounds for which χ(T) has in the past been considered by Sales and Wohlleben (SW) by applying their ICF model or by Lawrance et al. following their scaling procedure. It turned out that these phenomenological models can also be applied to the considered here two Ru-based uranium ternaries from which some reliable energy parameters could be found. In order to further support the mixing valence scenario for the first such cases in uranium compounds presented here, the transport and thermodynamic properties are also discussed. However, some of the most important results confirming the MV state, e.g., in U 2 RuGa 8 , has recently been achieved from the inelastic neutron scattering performed in the Rutherford Appleton Laboratory on the ISIS facility. From these measurements a characteristic gap of 60 meV has been

  19. Determination of carbon in uranium and its compounds; Determinacion de carbono en uranio metal y sus compuestos

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Garcia, M M

    1972-07-01

    This paper collects the analytical methods used our laboratories for the determination of carbon in uranium metal, uranate salts and the oxides, fluorides and carbides of uranium. The carbon is usually burned off in a induction or resistance oven under oxygen flow. The CO{sub 2} is collected in barite solution. Where it is backtitrated with potassium biphthalate. (Author)

  20. Antimicrobial activity of biopolymeric thin films containing flavonoid natural compounds and silver nanoparticles fabricated by MAPLE: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, R., E-mail: rodica.cristescu@inflpr.ro [National Institute for Lasers, Plasma & Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Visan, A.; Socol, G. [National Institute for Lasers, Plasma & Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Surdu, A.V.; Oprea, A.E.; Grumezescu, A.M. [Faculty of Applied Chemistry and Materials Science, Politehnica University of Bucharest, 1–7 Polizu Street, Bucharest, 011061 Romania (Romania); Chifiriuc, M.C. [Microbiology Immunology Department, Faculty of Biology, Research Institute of the University of Bucharest - ICUB, Bucharest, 77206 (Romania); Boehm, R.D.; Yamaleyeva, D.; Taylor, M.; Narayan, R.J. [Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC (United States); Chrisey, D.B. [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA (United States)

    2016-06-30

    Highlights: • We successfully deposited composite quercetin dehydrate-, resveratrol- and silver nanoparticle-polyvinylpyrrolidone thin coatings with chemical structure close to that of the starting materials by MAPLE. • Thin film morphology studies revealed a uniform surface without aggregates or grains on the top of the surface. • MAPLE-deposited thin films exhibited antibacterial activity against Gram-positive and Gram-negative bacterial strains. • We demonstrated the potential use of these hybrid systems and MAPLE deposition method for the development of new harmless, ecological antimicrobial strategies. - Abstract: The purpose of this study was to investigate the interactions between microorganisms, including the planktonic and adherent organisms, and biopolymer (polyvinylpyrrolidone), flavonoid (quercetin dihydrate and resveratrol)-biopolymer, and silver nanoparticles-biopolymer composite thin films that were deposited using matrix assisted pulsed laser evaporation (MAPLE). A pulsed KrF{sup *} excimer laser source was used to deposit the aforementioned composite thin films, which were characterized using Fourier transform infrared spectroscopy (FT-IR), infrared microscopy (IRM), scanning electron microscopy (SEM), Grazing incidence X-ray diffraction (GIXRD) and atomic force microscopy (AFM). The antimicrobial activity of thin films was quantified using an adapted disk diffusion assay against Gram-positive and Gram-negative bacteria strains. FT-IR, AFM and SEM studies confirmed that MAPLE may be used to fabricate thin films with chemical properties corresponding to the input materials as well as surface properties that are appropriate for medical use. The silver nanoparticles and flavonoid-containing films exhibited an antimicrobial activity both against Gram-positive and Gram-negative bacterial strains demonstrating the potential use of these hybrid systems for the development of novel antimicrobial strategies.

  1. Antimicrobial activity of biopolymeric thin films containing flavonoid natural compounds and silver nanoparticles fabricated by MAPLE: A comparative study

    International Nuclear Information System (INIS)

    Cristescu, R.; Visan, A.; Socol, G.; Surdu, A.V.; Oprea, A.E.; Grumezescu, A.M.; Chifiriuc, M.C.; Boehm, R.D.; Yamaleyeva, D.; Taylor, M.; Narayan, R.J.; Chrisey, D.B.

    2016-01-01

    Highlights: • We successfully deposited composite quercetin dehydrate-, resveratrol- and silver nanoparticle-polyvinylpyrrolidone thin coatings with chemical structure close to that of the starting materials by MAPLE. • Thin film morphology studies revealed a uniform surface without aggregates or grains on the top of the surface. • MAPLE-deposited thin films exhibited antibacterial activity against Gram-positive and Gram-negative bacterial strains. • We demonstrated the potential use of these hybrid systems and MAPLE deposition method for the development of new harmless, ecological antimicrobial strategies. - Abstract: The purpose of this study was to investigate the interactions between microorganisms, including the planktonic and adherent organisms, and biopolymer (polyvinylpyrrolidone), flavonoid (quercetin dihydrate and resveratrol)-biopolymer, and silver nanoparticles-biopolymer composite thin films that were deposited using matrix assisted pulsed laser evaporation (MAPLE). A pulsed KrF * excimer laser source was used to deposit the aforementioned composite thin films, which were characterized using Fourier transform infrared spectroscopy (FT-IR), infrared microscopy (IRM), scanning electron microscopy (SEM), Grazing incidence X-ray diffraction (GIXRD) and atomic force microscopy (AFM). The antimicrobial activity of thin films was quantified using an adapted disk diffusion assay against Gram-positive and Gram-negative bacteria strains. FT-IR, AFM and SEM studies confirmed that MAPLE may be used to fabricate thin films with chemical properties corresponding to the input materials as well as surface properties that are appropriate for medical use. The silver nanoparticles and flavonoid-containing films exhibited an antimicrobial activity both against Gram-positive and Gram-negative bacterial strains demonstrating the potential use of these hybrid systems for the development of novel antimicrobial strategies.

  2. Modern x-ray spectral methods in the study of the electronic structure of actinide compounds: Uranium oxide UO2 as an example

    Directory of Open Access Journals (Sweden)

    Teterin Yury A.

    2004-01-01

    Full Text Available Fine X-ray photo electron spectral (XPS structure of uranium dioxide UO2 in the binding energy (BE range 0-~č40 eV was associated mostly with the electrons of the outer (OVMO (0-15 eV BE and inner (IVMO (15-40 eV BE valence molecular orbitals formed from the incompletely U5f,6d,7s and O2p and completely filled U6p and O2s shells of neighboring uranium and oxygen ions. It agrees with the relativistic calculation results of the electronic structure for the UO812–(Oh cluster reflecting uranium close environment in UO2, and was confirmed by the X-ray (conversion electron, non-resonance and resonance O4,5(U emission, near O4,5(U edge absorption, resonance photoelectron, Auger spectroscopy data. The fine OVMO and IVMO related XPS structure was established to yield conclusions on the degree of participation of the U6p,5f electrons in the chemical bond, uranium close environment structure and interatomic distances in oxides. Total contribution of the IVMO electrons to the covalent part of the chemical bond can be comparable with that of the OVMO electrons. It has to be noted that the IVMO formation can take place in compounds of any elements from the periodic table. It is a novel scientific fact in solid-state chemistry and physics.

  3. Antimicrobial activity of biopolymeric thin films containing flavonoid natural compounds and silver nanoparticles fabricated by MAPLE: A comparative study

    Science.gov (United States)

    Cristescu, R.; Visan, A.; Socol, G.; Surdu, A. V.; Oprea, A. E.; Grumezescu, A. M.; Chifiriuc, M. C.; Boehm, R. D.; Yamaleyeva, D.; Taylor, M.; Narayan, R. J.; Chrisey, D. B.

    2016-06-01

    The purpose of this study was to investigate the interactions between microorganisms, including the planktonic and adherent organisms, and biopolymer (polyvinylpyrrolidone), flavonoid (quercetin dihydrate and resveratrol)-biopolymer, and silver nanoparticles-biopolymer composite thin films that were deposited using matrix assisted pulsed laser evaporation (MAPLE). A pulsed KrF* excimer laser source was used to deposit the aforementioned composite thin films, which were characterized using Fourier transform infrared spectroscopy (FT-IR), infrared microscopy (IRM), scanning electron microscopy (SEM), Grazing incidence X-ray diffraction (GIXRD) and atomic force microscopy (AFM). The antimicrobial activity of thin films was quantified using an adapted disk diffusion assay against Gram-positive and Gram-negative bacteria strains. FT-IR, AFM and SEM studies confirmed that MAPLE may be used to fabricate thin films with chemical properties corresponding to the input materials as well as surface properties that are appropriate for medical use. The silver nanoparticles and flavonoid-containing films exhibited an antimicrobial activity both against Gram-positive and Gram-negative bacterial strains demonstrating the potential use of these hybrid systems for the development of novel antimicrobial strategies.

  4. U for uranium

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    The Beisa Mine is unique in South Africa - it is the only underground mine with uranium as its main product and gold as a by-product. At the rate of 1,2 Mt/a, the life of Beisa is estimated on 26 years. Beisa's metallurgical plant is designed to handle initially a monthly throughput of 100 000t of ore, from which uranium, gold and silver will be extracted

  5. Manhattan Project Technical Series: The Chemistry of Uranium (I)

    International Nuclear Information System (INIS)

    Rabinowitch, E. I.; Katz, J. J.

    1947-01-01

    This constitutes Chapters 11 through 16, inclusive, of the Survey Volume on Uranium Chemistry prepared for the Manhattan Project Technical Series. Chapters are titled: Uranium Oxides, Sulfides, Selenides, and Tellurides; The Non-Volatile Fluorides of Uranium; Uranium Hexafluoride; Uranium-Chlorine Compounds; Bromides, Iodides, and Pseudo-Halides of Uranium; and Oxyhalides of Uranium.

  6. Manhattan Project Technical Series: The Chemistry of Uranium (I)

    Energy Technology Data Exchange (ETDEWEB)

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

    1947-03-10

    This constitutes Chapters 11 through 16, inclusive, of the Survey Volume on Uranium Chemistry prepared for the Manhattan Project Technical Series. Chapters are titled: Uranium Oxides, Sulfides, Selenides, and Tellurides; The Non-Volatile Fluorides of Uranium; Uranium Hexafluoride; Uranium-Chlorine Compounds; Bromides, Iodides, and Pseudo-Halides of Uranium; and Oxyhalides of Uranium.

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

    International Nuclear Information System (INIS)

    Rabinowitch, E. I.; Katz, J. J.

    1946-01-01

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

  8. MOD silver metallization for photovoltaics

    Science.gov (United States)

    Vest, G. M.; Vest, R. W.

    1984-01-01

    The development of flat plate solar arrays is reported. Photovoltaic cells require back side metallization and a collector grid system on the front surface. Metallo-organic decomposition (MOD) silver films can eliminate most of the present problems with silver conductors. The objectives are to: (1) identify and characterize suitable MO compounds; (2) develop generic synthesis procedures for the MO compounds; (3) develop generic fabrication procedures to screen printable MOD silver inks; (4) optimize processing conditions to produce grid patterns and photovoltaic cells; and (5) develop a model which describes the adhesion between the fired silver film and the silicon surface.

  9. Study of in vitro toxicity and ex vivo and in vivo efficiency of calixarene galenic forms developed for the treatment of cutaneous contamination due to uranium compounds

    International Nuclear Information System (INIS)

    Grives, Sophie

    2015-01-01

    In case of radiological skin contamination by uranium compounds, the only treatments currently available consist in rinsing the contaminated skin area with water and detergent, or with a calcium salt of diethylene triamine pentaacetic acid (Ca-DTPA) solution. However, these procedures are not specific and no efficient treatment for cutaneous contamination due to uranium exists. In the absence of such treatments, uranium diffusion through the skin is fast, inducing an internal exposure after its distribution inside the body through the bloodstream. One part of the bioavailable uranium is up-taken in target organs which are the kidneys and the skeleton, where its toxic effects occur. Therefore a topical formulation consisting of an oil-in-water nano-emulsion incorporating a tricarboxylic calixarene molecule, as a specific chelating agent for uranium, was previously developed. The work achieved in this thesis aimed at evaluating the ex vivo and in vivo decontamination efficiency of this new emergency treatment on intact and superficially wounded skin. For this purpose, skin excoriation model was used. Reproducible models of superficial wounds consisting of micro-cuts and micro-punctures were also developed in order to evaluate the efficiency of the nano-emulsion on physical wounds such as incisions. These studies showed that the calixarene nano-emulsion could be an efficient decontaminating treatment, less aggressive than using the current treatment: soaped water. Its potential cutaneous toxicity was evaluated on in vitro reconstructed human epidermis using three different toxicity tests (MTT, LDH and IL-1-α). These studies demonstrated that the calixarene nano-emulsion did not induce skin toxicity even after 24 h of exposure time. (author)

  10. Analytical method development and validation for quantification of uranium in compounds of the nuclear fuel cycle by Fourier Transform Infrared (FTIR) Spectroscopy

    International Nuclear Information System (INIS)

    Pereira, Elaine

    2016-01-01

    This work presents a low cost, simple and new methodology for direct quantification of uranium in compounds of the nuclear fuel cycle, based on Fourier Transform Infrared (FTIR) spectroscopy using KBr pressed discs technique. Uranium in different matrices were used to development and validation: UO 2 (NO 3 )2.2TBP complex (TBP uranyl nitrate complex) in organic phase and uranyl nitrate (UO 2 (NO 3 ) 2 ) in aqueous phase. The parameters used in the validation process were: linearity, selectivity, accuracy, limits of detection (LD) and quantitation (LQ), precision (repeatability and intermediate precision) and robustness. The method for uranium in organic phase (UO 2 (NO 3 )2.2TBP complex in hexane/embedded in KBr) was linear (r = 0.9980) over the range of 0.20% 2.85% U/ KBr disc, LD 0.02% and LQ 0.03%, accurate (recoveries were over 101.0%), robust and precise (RSD < 1.6%). The method for uranium aqueous phase (UO 2 (NO 3 ) 2 /embedded in KBr) was linear (r = 0.9900) over the range of 0.14% 1.29% U/KBr disc, LD 0.01% and LQ 0.02%, accurate (recoveries were over 99.4%), robust and precise (RSD < 1.6%). Some process samples were analyzed in FTIR and compared with gravimetric and X-ray fluorescence (XRF) analyses showing similar results in all three methods. The statistical tests (t-Student and Fischer) showed that the techniques are equivalent. The validated method can be successfully employed for routine quality control analysis for nuclear compounds. (author)

  11. Depleted uranium - 'the silver bullet'

    International Nuclear Information System (INIS)

    Munoz-Ferrada, C.; Wollongong University, NSW

    2001-01-01

    Article 35 of the Geneva protocols, signed by 150 countries in 1949 and an additional protocol signed from 1977 onwards prohibited the use of weapons that cause and inflict unnecessary injury and suffering. In the recent wars such as Bosnia, Kosovo and the Gulf War, more than 31,000 missiles were launched against enemy lines containing DU and more than 300 tonnes of DU during the Gulf War alone. DU is a radioactive and toxic element. In humans it can cause lung cancer, damage to the liver and kidney affecting the bone marrow and consequently destroying stem cells that form the white cells resulting in mutations and the long lasting effect of genetic damage

  12. Scaling properties for the first RE-like mixed valence examples in uranium compounds: U2Ru2Sn and U2RuGa8

    International Nuclear Information System (INIS)

    Troc, Robert

    2006-01-01

    The present study was motivated by the scaling characterization of the first example of mixed valence (MV) RE-like behaviour found recently among intermetallic ternary uranium compounds. The χ(T) function for both title compounds has been fitted to the interconfigurational fluctuation (ICF) model of Sales and Wohlleben in order to determine the characteristic fluctuation temperatures T sf and interconfigurational excitation energies E ex . A good scaling, with similar values of T sf like from those derived from the ICF model, has been achieved for both these ternaries by plotting Tχ(T)/C against the reduced T/T sf . Moreover, this scaling follows almost exactly those found earlier in a number of MV- RE compounds

  13. Crystal field effect in the uranium compounds - model calculations for CsUF/sub 6/, Cs/sub 2/UCl/sub 6/ and UCl/sub 4/

    Energy Technology Data Exchange (ETDEWEB)

    Gajek, Z.; Mulak, J.; Faucher, M.

    1987-01-01

    A practical crystal field model allowing one to estimate the crystal field parameters from first principles is presented and applied to the actinide compounds. The model results directly from the renormalization (and reduction) procedure of the true Schroedinger equation for an effective Hamiltonian acting on the 5f spin-orbitals only. In practice this approach becomes convergent with the ab initio model of Newman. Three ionic uranium compounds: CsUF/sub 6/, Cs/sub 2/UCl/sub 6/ and UCl/sub 4/ have served as examples of the application. The results obtained, particularly for the first two compounds, are in good agreement with the experimental data. The contributions of different mechanisms responsible for the crystal field effect are discussed.

  14. Crystal field effect in the uranium compounds - model calculations for CsUF6, Cs2UCl6 and UCl4

    International Nuclear Information System (INIS)

    Gajek, Z.; Mulak, J.

    1987-01-01

    A practical crystal field model allowing one to estimate the crystal field parameters from first principles is presented and applied to the actinide compounds. The model results directly from the renormalization (and reduction) procedure of the true Schroedinger equation for an effective Hamiltonian acting on the 5f spin-orbitals only. In practice this approach becomes convergent with the ab initio model of Newman. Three ionic uranium compounds: CsUF 6 , Cs 2 UCl 6 and UCl 4 have served as examples of the application. The results obtained, particularly for the first two compounds, are in good agreement with the experimental data. The contributions of different mechanisms responsible for the crystal field effect are discussed. (author)

  15. Selective arsenical purification of substances during an alkaline treatment process of an uranium and/or molybdenum bearing ore by means of a magnesium compound

    International Nuclear Information System (INIS)

    Maurel, Pierre; Lamerant, J.M.; Pallez, Francois.

    1983-01-01

    The ores is digested by means of an aqueous liquor of sodium or potassium carbonate and/or bicarbonate, the digestion being carried out under conditions of concentrations, temperatures and pressures bringing about the solubilization of the uranium and/or molybdenum and the arsenic present in the core. A solid phase suspension is lifted from a liquid phase and the phases are separated. The arsenic solubilized during the digestion is extracted as magnesium arsenate by treatment of the medium containing the arsenic by means of a magnesium compound [fr

  16. Plasmonic photocatalysts based on silver nanoparticles - layered double hydroxides for efficient removal of toxic compounds using solar light

    Science.gov (United States)

    Gilea, Diana; Radu, Teodora; Muresanu, Mihaela; Carja, Gabriela

    2018-06-01

    Plasmon-enhanced photocatalysis holds important promise for chemical processes and outcomes. We present here the self-assemblies of silver nanoparticles (AgNP)/layered double hydroxides (LDHs: MeAlLDHs with Me2+ = Zn2+;Mg2+) and their derived AgNP/MMOs (type AgNP/MgAl2O4; AgNP/ZnO/ZnAl2O4) as novel plasmonic photocatalysts exhibiting activity for phenol photodegradation from aqueous solution by solar-light. The fabrication procedure of AgNP/LDHs assemblies is simple and cost effective and is based on the in-situ synthesis of AgNP on the LDHs matrices during the reconstruction of MgAlLDH and ZnAlLDH in the aqueous solution of Ag2SO4. The tested catalysts were thoroughly investigated - techniques to obtain information on their crystalline structure (XRD), surface properties (XPS), morphological features (TEM) and optical properties (UV-vis). The results show that the solar photocatalytic response of the catalysts is ascribed to the plasmonic response of AgNP though the catalytic efficiency is strongly influenced by the composition of the MeAlLDHs. The best photocatalytic performance was obtained on AgNP/ZnAlLDH750 catalyst that degraded 100% of phenol after 80 min of irradiation with solar light. The results reveal the high potential to tailor AgNP/LDHs and AgNP/MMOs as efficient photo-functional plasmonic hybrids for waste-water cleaning.

  17. The determination of small amounts of fluoride in uranium compounds by use of an ion-selective electrode

    International Nuclear Information System (INIS)

    Shelton, B.M.

    1975-01-01

    A method is presented for the determination of fluoride in uranium metal and oxide at levels from 16 p.p.m. upwards. Uranium is separated from fluoride by extraction into a solution of di(2-ethylhexyl)-phosphoric acid (HDEHP) in carbon tetrachloride. The fluoride remaining in the aqueous phase is determined by potentiometric measurement with an ion-selective electrode. A correction is made for the fluoride lost during the dissolution or extraction step, or both, which is based on a determination of the apparent loss of fluoride on spiked samples that are taken through the whole procedure [af

  18. Tools for Chemical Biology: New Macrocyclic Compounds from Diversity-Oriented Synthesis and Toward Materials from Silver(I) Acetylides

    DEFF Research Database (Denmark)

    Madsen, Charlotte Marie

    Part I The formation of a library of diverse macrocyclic compounds with different functionalities and ring sizes in a few steps from two easily accessible α,ω-diol building blocks is presented. The building blocks are combined by esteriffcations in four different ways leading to the formation of ...... of uoro-iodoadamantanes. However, overall the results provide a good starting point for the synthesis of new triptycene and adamantane-containing molecules that can interact with carbon nanotubes....

  19. Biomimetic synthesis of silver nanoparticles using the fish scales of Labeo rohita and their application as catalysts for the reduction of aromatic nitro compounds

    Science.gov (United States)

    Sinha, Tanur; Ahmaruzzaman, M.; Sil, A. K.; Bhattacharjee, Archita

    2014-10-01

    In this article, a cleaner, greener, cheaper and environment friendly method for the generation of self assembled silver nanoparticles (Ag NPs) applying a simple irradiation technique using the aqueous extract of the fish scales (which is considered as a waste material) of Labeo rohita is described. Gelatin is considered as the major ingredient responsible for the reduction as well as stabilisation of the self assembled Ag NPs. The size and morphology of the individual Ag NPs can be tuned by controlling the various reaction parameters, such as temperature, concentration, and pH. Studies showed that on increasing concentration and pH Ag NPs size decreases, while on increasing temperature, Ag NPs size increases. The present process does not need any external reducing agent, like sodium borohydride or hydrazine or others and gelatin itself can play a dual role: a ‘reducing agent' and ‘stabilisation agent' for the formation of gelatin-Ag NPs colloidal dispersion. The synthesized Ag NPs were characterised by Ultraviolet-Visible spectroscopy (UV-Vis), Transmission electron microscopy (TEM) and Selected area electron diffraction (SAED) analyses. The synthesized Ag NPs was used to study the catalytic reduction of various aromatic nitro compounds in aqueous and three different micellar media. The hydrophobic and electrostatic interaction between the micelle and the substrate is responsible for the catalytic activity of the nanoparticles in micelle.

  20. Chemical thermodynamics of uranium

    International Nuclear Information System (INIS)

    Grenthe, I.; Fuger, J.; Lemire, R.J.; Muller, A.B.; Nguyen-Trung Cregu, C.; Wanner, H.

    1992-01-01

    A comprehensive overview on the chemical thermodynamics of those elements that are of particular importance in the safety assessment of radioactive waste disposal systems is provided. This is the first volume in a series of critical reviews to be published on this subject. The book provides an extensive compilation of chemical thermodynamic data for uranium. A description of procedures for activity corrections and uncertainty estimates is given. A critical discussion of data needed for nuclear waste management assessments, including areas where significant gaps of knowledge exist is presented. A detailed inventory of chemical thermodynamic data for inorganic compounds and complexes of uranium is listed. Data and their uncertainty limits are recommended for 74 aqueous complexes and 199 solid and 31 gaseous compounds containing uranium, and on 52 aqueous and 17 solid auxiliary species containing no uranium. The data are internally consistent and compatible with the CODATA Key Values. The book contains a detailed discussion of procedures used for activity factor corrections in aqueous solution, as well as including methods for making uncertainty estimates. The recommended data have been prepared for use in environmental geochemistry. Containing contributions written by experts the chapters cover various subject areas such a s: oxide and hydroxide compounds and complexes, the uranium nitrides, the solid uranium nitrates and the arsenic-containing uranium compounds, uranates, procedures for consistent estimation of entropies, gaseous and solid uranium halides, gaseous uranium oxides, solid phosphorous-containing uranium compounds, alkali metal uranates, uncertainties, standards and conventions, aqueous complexes, uranium minerals dealing with solubility products and ionic strength corrections. The book is intended for nuclear research establishments and consulting firms dealing with uranium mining and nuclear waste disposal, as well as academic and research institutes

  1. The Use of Silver Solid Amalgam Electrodes for Voltammetric and Amperometric Determination of Nitrated Polyaromatic Compounds Used as Markers of Incomplete Combustion

    Directory of Open Access Journals (Sweden)

    Oksana Yosypchuk

    2012-01-01

    Full Text Available Genotoxic nitrated polycyclic aromatic hydrocarbons (NPAHs are formed during incomplete combustion processes by reaction of polycyclic aromatic hydrocarbons (PAHs with atmospheric nitrogen oxides. 1-Nitropyrene, 2-nitrofluorene, and 3-nitrofluoranthene as the dominating substances are used as markers of NPAHs formation by these processes. In the presented study, voltammetric properties and quantification of these compounds and of 5-nitroquinoline (as a representative of environmentally important genotoxic heterocyclic compounds have been investigated using a mercury meniscus modified silver solid amalgam electrode (m-AgSAE, which represent a nontoxic alternative to traditional mercury electrodes. Linear calibration curves over three orders of magnitude and limits of determination mostly in the 10−7 mol L−1 concentration range were obtained using direct current and differential pulse voltammetry. Further, satisfactory HPLC separation of studied analytes in fifteen minutes was achieved using 0.01 mol L−1 phosphate buffer, pH 7.0 : methanol (15 : 85, v/v mobile phase, and C18 reversed stationary phase. Limits of detection of around 1 · 10−5 mol L−1 were achieved using amperometric detection at m-AgSAE in wall-jet arrangement for all studied analytes. Practical applicability of this technique was demonstrated on the determination of 1-nitropyrene, 2-nitrofluorene, 3-nitrofluoranthene, and 5-nitroquinoline in drinking water after their preliminary separation and preconcentration using solid phase extraction with the limits of detection around 1 · 10−6 mol L−1.

  2. Mineral commodity profiles: Silver

    Science.gov (United States)

    Butterman, W.C.; Hilliard, Henry E.

    2005-01-01

    Overview -- Silver is one of the eight precious, or noble, metals; the others are gold and the six platinum-group metals (PGM). World mine production in 2001 was 18,700 metric tons (t) and came from mines in 60 countries; the 10 leading producing countries accounted for 86 percent of the total. The largest producer was Mexico, followed by Peru, Australia, and the United States. About 25 percent of the silver mined in the world in 2001 came from silver ores; 15 percent, from gold ores and the remaining 60 percent, from copper, lead, and zinc ores. In the United States, 14 percent of the silver mined in 2001 came from silver ores; 39 percent, from gold ores; 10 percent, from copper and copper-molybdenum ores; and 37 percent, from lead, zinc, and lead-zinc ores. The precious metal ores (gold and silver) came from 30 lode mines and 10 placer mines; the base-metal ores (copper, lead, molybdenum, and zinc) came from 24 lode mines. Placer mines yielded less than 1 percent of the national silver production. Silver was mined in 12 States, of which Nevada was by far the largest producer; it accounted for nearly one-third of the national total. The production of silver at domestic mines generated employment for about 1,100 mine and mill workers. The value of mined domestic silver was estimated to be $290 million. Of the nearly 27,000 t of world silver that was fabricated in 2001, about one-third went into jewelry and silverware, one-fourth into the light-sensitive compounds used in photography, and nearly all the remainder went for industrial uses, of which there were 7 substantial uses and many other small-volume uses. By comparison, 85 percent of the silver used in the United States went to photography and industrial uses, 8 percent to jewelry and silverware, and 7 percent to coins and medals. The United States was the largest consumer of silver followed by India, Japan, and Italy; the 13 largest consuming countries accounted for nearly 90 percent of the world total. In the

  3. Uranium's scientific history

    International Nuclear Information System (INIS)

    Goldschmidt, B.

    1990-01-01

    The bicentenary of the discovery of uranium coincides with the fiftieth anniversary of the discovery of fission, an event of worldwide significance and the last episode in the uranium -radium saga which is the main theme of this paper. Uranium was first identified by the German chemist Martin Klaproth in 1789. He extracted uranium oxide from the ore pitchblende which was a by-product of the silver mines at Joachimsthal in Bohemia. For over a century after its discovery, the main application for uranium derived from the vivid colours of its oxides and salts which are used in glazes for ceramics, and porcelain. In 1896, however, Becquerel discovered that uranium emitted ionizing radiation. The extraction by Pierre and Marie Curie of the more radioactive radium from uranium in the early years of the twentieth century and its application to the treatment of cancer shifted the chief interest to radium production. In the 1930s the discovery of the neutron and of artificial radioactivity stimulated research in a number of European laboratories which culminated in the demonstration of fission by Otto Frisch in January 1939. The new found use of uranium for the production of recoverable energy, and the creation of artificial radioelements in nuclear reactors, eliminated the radium industry. (author)

  4. High-performance liquid chromatography separation of unsaturated organic compounds by a monolithic silica column embedded with silver nanoparticles.

    Science.gov (United States)

    Zhu, Yang; Morisato, Kei; Hasegawa, George; Moitra, Nirmalya; Kiyomura, Tsutomu; Kurata, Hiroki; Kanamori, Kazuyoshi; Nakanishi, Kazuki

    2015-08-01

    The optimization of a porous structure to ensure good separation performances is always a significant issue in high-performance liquid chromatography column design. Recently we reported the homogeneous embedment of Ag nanoparticles in periodic mesoporous silica monolith and the application of such Ag nanoparticles embedded silica monolith for the high-performance liquid chromatography separation of polyaromatic hydrocarbons. However, the separation performance remains to be improved and the retention mechanism as compared with the Ag ion high-performance liquid chromatography technique still needs to be clarified. In this research, Ag nanoparticles were introduced into a macro/mesoporous silica monolith with optimized pore parameters for high-performance liquid chromatography separations. Baseline separation of benzene, naphthalene, anthracene, and pyrene was achieved with the theoretical plate number for analyte naphthalene as 36,000 m(-1). Its separation function was further extended to cis/trans isomers of aromatic compounds where cis/trans stilbenes were chosen as a benchmark. Good separation of cis/trans-stilbene with separation factor as 7 and theoretical plate number as 76,000 m(-1) for cis-stilbene was obtained. The trans isomer, however, is retained more strongly, which contradicts the long- established retention rule of Ag ion chromatography. Such behavior of Ag nanoparticles embedded in a silica column can be attributed to the differences in the molecular geometric configuration of cis/trans stilbenes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. The crystal chemistry of novel thorium and uranium compounds with oxo-anions from group VI of periodic table (S, Se, Te, Cr, Mo and W)

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Bin

    2016-01-26

    This dissertation focus on the synthesis, phase studies and physicochemical properties of novel thorium and uranium compounds with the Group VI (S, Se, Te, Cr, Mo, W) of the Periodic Table. All the studied compounds are listed in Table 2.2 from the page 15. I subdivided all the newly synthesized compounds into several chapters according to their structural and topological differences. First, for thorium molybdates and tungstates, almost all of these compounds are based on corner-sharing of ThO{sub x} (x = 6, 8 and 9) and MoO{sub 4} or WO{sub x} (x = 4, 5, 6) polyhedra. Interestingly, all these compounds can be seen as derived from a pure thorium molybdate compound (ThMo{sub 2}O{sub 8}) which was isolated from high-temperature solid-state synthesis method. Therefore, the polymorphs of this most basic ThMo{sub 2}O{sub 8} compound is firstly introduced (see Chapter 3.1 from page 18). The thermodynamic, electronic and vibrational properties of all investigated ThMo{sub 2}O{sub 8} polymorphs were studied using ab initio calculations. Then, two subfamilies of thorium molybdates, that is, rubidium thorium molybdate and cesium thorium molybdate and their thermal and vibrational behaviors were discussed in details in Chapter 4.1 from page 37 and Chapter 4.2 from page 50, respectively. Moreover, some new insights about the complexity of thorium tungstates were also discussed (Chapter 4.3 from page 59). Some novel thorium molybdate and chromate compounds synthesized from aqueous condition are discussed in Chapter 5 from page 71. In the Chapter 8.2.4, the stereochemistry for thorium and uranium compounds are introduced, especially thorium selinites and uranyl tellurites (see Chapter 6.1 from page 82), thorium tellurites (Chapter 6.2 from page 93), and uranyl tellurites (Chapter 6.3 from page 99 for sodium uranyl tellurium and Chapter 6.4 from page 110 for potassium uranyl tellurium, respectively). In the actinide tellurium systems, additional MoO{sub 3}/WO{sub 3} were also

  6. No fluorinated compounds in the uranium conversion process: risk analysis and proposition of pictograms; Os compostos nao fluorados nos processos da conversao do uranio: analise de riscos e proposicao de pictogramas

    Energy Technology Data Exchange (ETDEWEB)

    Jeronimo, Adroaldo Clovis; Oliveira, Wagner dos Santos, E-mail: acejota18@yahoo.com.br, E-mail: oliveira@feq.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Quimica; Aquino, Afonso Rodrigues de, E-mail: araquino@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-03-15

    The plants comprising the chemical conversion of uranium, which are part of the nuclear fuel cycle, present some risks, among others, because are associated with the non-fluorinated compounds handled in these processes. This study is the analysis of the risks associated with these compounds, i e, the non-fluorinated reactants and products, handled in different chemical processing plants, which include the production of uranium hexafluoride, while emphasizing the responsibilities and actions that fit to the chemical engineer with regard to minimizing risks during the various stages. The work is based on the experience gained during the development and mastery of the technology of production of uranium hexafluoride, the IPEN/ CNEN-SP, during the '80s, with the support of COPESP -Navy of Brazil. (author)

  7. Raman Investigation of The Uranium Compounds U3O8, UF4, UH3 and UO3 under Pressure at Room Temperature

    International Nuclear Information System (INIS)

    Lipp, M.J.; Jenei, Z.; Park-Klepeis, J.; Evans, W.J.

    2011-01-01

    Our current state-of-the-art X-ray diffraction experiments are primarily sensitive to the position of the uranium atom. While the uranium - low-Z element bond (such as U-H or U-F) changes under pressure and temperature the X-ray diffraction investigations do not reveal information about the bonding or the stoichiometry. Questions that can be answered by Raman spectroscopy are (i) whether the bonding strength changes under pressure, as observed by either blue- or red-shifted peaks of the Raman active bands in the spectrum and (ii) whether the low-Z element will eventually be liberated and leave the host lattice, i.e. do the fluorine, oxygen, or hydrogen atoms form dimers after breaking the bond to the uranium atom. Therefore Raman spectra were also collected in the range where those decomposition products would appear. Raman is particularly well suited to these types of investigations due to its sensitivity to trace amounts of materials. One challenge for Raman investigations of the uranium compounds is that they are opaque to visible light. They absorb the incoming radiation and quickly heat up to the point of decomposition. This has been dealt with in the past by keeping the incoming laser power to very low levels on the tens of milliWatt range consequently affecting signal to noise. Recent modern investigations also used very small laser spot sizes (micrometer range) but ran again into the problem of heating and chemical sensitivity to the environment. In the studies presented here (in contrast to all other studies that were performed at ambient conditions only) we employ micro-Raman spectroscopy of samples situated in a diamond anvil cell. This increases the trustworthiness of the obtained data in several key-aspects: (a) We surrounded the samples in the DAC with neon as a pressure transmitting medium, a noble gas that is absolutely chemically inert. (b) Through the medium the sample is thermally heat sunk to the diamond anvils, diamond of course possessing the

  8. Phospholyl-uranium complexes

    International Nuclear Information System (INIS)

    Gradoz, Philippe

    1993-01-01

    After having reported a bibliographical study on penta-methylcyclopentadienyl uranium complexes, and a description of the synthesis and radioactivity of uranium (III) and (IV) boron hydrides compounds, this research thesis reports the study of mono and bis-tetramethyl-phospholyl uranium complexes comprising chloride, boron hydride, alkyl and alkoxide ligands. The third part reports the comparison of structures, stabilities and reactions of homologue complexes in penta-methylcyclopentadienyl and tetramethyl-phospholyl series. The last part addresses the synthesis of tris-phospholyl uranium (III) and (IV) complexes. [fr

  9. Separation of uranium isotopes by accelerated isotope exchange reactions

    International Nuclear Information System (INIS)

    Seko, M.; Miyake, T.; Inada, K.; Ochi, K.; Sakamoto, T.

    1977-01-01

    A novel catalyst for isotope exchange reaction between uranium(IV) and uranium(VI) compounds enables acceleration of the reaction rate as much as 3000 times to make industrial separation of uranium isotopes economically possible

  10. Titrimetric determination of uranium

    International Nuclear Information System (INIS)

    Florence, T.M.

    1989-01-01

    Titrimetric methods are almost invariably used for the high precision assay of uranium compounds, because gravimetric methods are nonselective, and not as reliable. Although precipitation titrations have been used, for example with cupferron and ferrocyanide, and chelate titrations with EDTA and oxine give reasonable results, in practice only redox titrations find routine use. With all redox titration methods for uranium a precision of 01 to 02 percent can be achieved, and precisions as high as 0.003 percent have been claimed for the more refined techniques. There are two types of redox titrations for uranium in common use. The first involves the direct titration of uranium (VI) to uranium (IV) with a standard solution of a strong reductant, such as chromous chloride or titanous chloride, and the second requires a preliminary reduction of uranium to the (IV) or (III) state, followed by titration back to the (VI) state with a standard oxidant. Both types of redox titrations are discussed. 4 figs

  11. Study of internal exposure to uranium compounds in fuel fabrication plants in Brazil; Estudo da exposicao interna a compostos de uranio na fabricacao do elemento combustivel nuclear no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Maristela Souza

    2006-07-01

    The International Commission on Radiological Protection (ICRP) Publication 66 and Supporting Guidance 3) strongly recommends that specific information on lung retention parameters should be used in preference to default values wherever appropriate, for the derivation of effective doses and for bioassay interpretation of monitoring data. A group of 81 workers exposed to UO{sub 2} at the fuel fabrication facility in Brazil was selected to evaluate the committed effective dose. The workers were monitored for determination of uranium content in the urinary and faecal excretion. The contribution of intakes by ingestion and inhalation were assessed on the basis of the ratios of urinary to fecal excretion. For the selected workers it was concluded that inhalation dominated intake. According to ICRP 66, uranium oxide is classified as insoluble Type S compound. The ICRP Supporting Guidance 3 and some recent studies have recommended specific lung retention parameters to UO{sub 2}. The solubility parameters of the uranium oxide compound handled by the workers at the fuel fabrication facility in Brazil was evaluated on the basis of the ratios of urinary to fecal excretion. Excretion data were corrected for dietary intakes. This paper will discuss the application of lung retention parameters recommended by the ICRP models to these data and also the dependence of the effective committed dose on the lung retention parameters. It will also discuss the problems in the interpretation of monitoring results, when the worker is exposed to several uranium compounds of different solubilities. (author)

  12. Method of semi-automatic high precision potentiometric titration for characterization of uranium compounds; Metodo de titulacao potenciometrica de alta precisao semi-automatizado para a caracterizacao de compostos de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Cristiano, Barbara Fernandes G.; Dias, Fabio C.; Barros, Pedro D. de; Araujo, Radier Mario S. de; Delgado, Jose Ubiratan; Silva, Jose Wanderley S. da, E-mail: barbara@ird.gov.b, E-mail: fabio@ird.gov.b, E-mail: pedrodio@ird.gov.b, E-mail: radier@ird.gov.b, E-mail: delgado@ird.gov.b, E-mail: wanderley@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Lopes, Ricardo T., E-mail: ricardo@lin.ufrj.b [Universidade Federal do Rio de Janeiro (LIN/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Lab. de Instrumentacao Nuclear

    2011-10-26

    The method of high precision potentiometric titration is widely used in the certification and characterization of uranium compounds. In order to reduce the analysis and diminish the influence if the annalist, a semi-automatic version of the method was developed at the safeguards laboratory of the CNEN-RJ, Brazil. The method was applied with traceability guaranteed by use of primary standard of potassium dichromate. The standard uncertainty combined in the determination of concentration of total uranium was of the order of 0.01%, which is better related to traditionally methods used by the nuclear installations which is of the order of 0.1%

  13. Silver niobates

    International Nuclear Information System (INIS)

    Tanirbergenov, B.; Rozhenko, S.P.

    1979-01-01

    By means of determination of residual concentrations and pH measurements investigated are the AgNO 3 -KNbO 3 -H 2 O, AgNO 3 -K 3 NbO 4 -H 2 O, AgNO 3 -K 8 Nb 16 O 19 -H 2 O systems and established is formation of meta-, ortho-and hexaniobates of silver. AgNbO 3 x H 2 O, Ag 8 Nb 6 O 19 x 6H 2 O and Ag 3 NbO 3 x 2.5H 2 O are separated from aqueous solution. Using the methods of differential-thermal, thermogravimetric and X-ray-phase analyses it is shown that silver metaniobate transforms into the crystal state at 530 deg C. Ortho- and hexaniobate of silver decompose at 500 deg C with formation of silver metaniobate and metal silver

  14. Effect of different uranium compounds on the properties of U-Pt-Y-Ba-O double-perovskite pinning centres in textured Y-Ba-Cu-O superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Sawh, Ravi-Persad; Weinstein, Roy; Parks, Drew; Gandini, Alberto [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Department of Physics, University of Houston, Houston, TX 77204-5005 (United States); Texas Center for Superconductivity and Advanced Materials, University of Houston, Houston, TX 77204-5005 (United States)

    2005-02-01

    An experiment was performed to test the effect of different uranium compounds on the properties of chemical pinning centres. UO{sub 2}, UO{sub 3}, and UO{sub 4}{center_dot}2H{sub 2}O wereadmixed to Y 123+Pt, and textured. Tests of J{sub c} via measurements of trapped field (B{sub trap}) indicate a clear dependence of B{sub trap} on the U compound admixed to create the pinning centres. In all three cases there is a monotonic increase in B{sub trap} as the mass (M{sub U}) of U is increased. However, the magnitude of the increase in B{sub trap} depends on the admixed U compound. The highest increase in B{sub trap} is measured in samples doped with UO{sub 4}{center_dot}2H{sub 2}O, and the lowest is obtained in samples doped with UO{sub 2}. Microstructure studies indicate that the composition of the U-rich pinning deposits is the same in all three cases, i.e. all are the previously identified (U{sub 0.6}Pt{sub 0.4})Y Ba{sub 2}O{sub 6} compound. The primary difference among the three types of samples is that the size of the U-Pt-Y-Ba-O pinning deposits depends on the admixed U compound. While all are in the nanometre domain, the diameter of these deposits was markedly larger in UO{sub 2} doped samples than in UO{sub 3} doped samples, and smallest in UO{sub 4}{center_dot}2H{sub 2}O doped samples. Because some form of poisoning limits the amount of U that can be added to create pinning centres, to M{sub U} {approx}1 wt%, smaller deposits result in a greater number of pinning centres. We conclude that UO{sub 4}{center_dot}2H{sub 2}O is more effective than either UO{sub 3} or UO{sub 2} in the formation of U-Pt-Y-Ba-O pinning centres because of diminished pinning centre size, and consequent increase in pinning centre density.

  15. Safety criteria of uranium enrichment plants

    International Nuclear Information System (INIS)

    Nardocci, A.C.; Oliveira Neto, J.M. de

    1994-01-01

    The applicability of nuclear reactor safety criteria applied to uranium enrichment plants is discussed, and a new criterion based on the soluble uranium compounds and hexafluoride chemical toxicities is presented. (L.C.J.A.). 21 refs, 4 tabs

  16. Effect of flavin compounds on uranium(VI) reduction- kinetic study using electrochemical methods with UV-vis spectroscopy

    International Nuclear Information System (INIS)

    Yamasaki, Shinya; Tanaka, Kazuya; Kozai, Naofumi; Ohnuki, Toshihiko

    2017-01-01

    The reduction of uranium hexavalent (U(VI)) to tetravalent (U(IV)) is an important reaction because of the change in its mobility in the natural environment. Although the flavin mononucleotide (FMN) has acted as an electron shuttle for the U(VI) reduction in vivo system, which is called an electron mediator, only the rate constant for the electron transfer from FMN to U(VI) has been determined. This study examined the rate constant for the U(VI) reduction process by three flavin analogues (riboflavin, flavin mononucleotide, flavin adenine dinucleotide) to elucidate their substituent group effect on the U(VI) reduction rate by electrochemical methods. The formation of the U(IV) was monitored by UV-vis spectrometry at 660 nm during the constant potential electrolysis of the U(VI) solution in the presence of the mediator. The cyclic voltammograms indicated that the three flavin analogues behaved as electron mediator to reduce U(VI). The logarithmic rate constant for the U(VI) reduction was related to the standard redox potential of the mediators. This linear relationship indicated that the redox-active group of the mediator and the substituent group of the mediator dominate capability of the U(VI) reduction and its rate, respectively. The apparent reduction potential of U(VI) increased about 0.2 V in the presence of the mediators, which strongly suggests that the biological electron mediator makes the U(VI) reduction possible even under more oxidative conditions. - Highlights: • The rate constant for the U(VI) reduction by flavin analogues was determined. • The flavins showed a mediator effect on the U(VI) reduction. • The logarithmic rate constants for the U(VI) reduction was proportional to redox potential of the mediator. • The presence of the mediator increased about 0.2 V apparent redox potential of U(VI) to U(IV).

  17. Gravimetric and volumetric determination of the purity of electrolytically refined silver and the produced silver nitrate

    Directory of Open Access Journals (Sweden)

    Ačanski Marijana M.

    2007-01-01

    Full Text Available Silver is, along with gold and the platinum-group metals, one of the so called precious metals. Because of its comparative scarcity, brilliant white color, malleability and resistance to atmospheric oxidation, silver has been used in the manufacture of coins and jewelry for a long time. Silver has the highest known electrical and thermal conductivity of all metals and is used in fabricating printed electrical circuits, and also as a coating for electronic conductors. It is also alloyed with other elements such as nickel or palladium for use in electrical contacts. The most useful silver salt is silver nitrate, a caustic chemical reagent, significant as an antiseptic and as a reagent in analytical chemistry. Pure silver nitrate is an intermediate in the industrial preparation of other silver salts, including the colloidal silver compounds used in medicine and the silver halides incorporated into photographic emulsions. Silver halides become increasingly insoluble in the series: AgCl, AgBr, AgI. All silver salts are sensitive to light and are used in photographic coatings on film and paper. The ZORKA-PHARMA company (Sabac, Serbia specializes in the production of pharmaceutical remedies and lab chemicals. One of its products is chemical silver nitrate (argentum-nitricum (l. Silver nitrate is generally produced by dissolving pure electrolytically refined silver in hot 48% nitric acid. Since the purity of silver nitrate, produced in 2002, was not in compliance with the p.a. level of purity, there was doubt that the electrolytically refined silver was pure. The aim of this research was the gravimetric and volumetric determination of the purity of electrolytically refined silver and silver nitrate, produced industrially and in a laboratory. The purity determination was carried out gravimetrically, by the sedimentation of silver(I ions in the form of insoluble silver salts: AgCl, AgBr and Agi, and volumetrically, according to Mohr and Volhardt. The

  18. Uranium (IV) carboxylates - I

    Energy Technology Data Exchange (ETDEWEB)

    Satpathy, K C; Patnaik, A K [Sambalpur Univ. (India). Dept. of Chemistry

    1975-11-01

    A few uranium(IV) carboxylates with monochloro and trichloro acetic acid, glycine, malic, citric, adipic, o-toluic, anthranilic and salicylic acids have been prepared by photolytic methods. The I.R. spectra of these compounds are recorded and basing on the spectral data, structure of the compounds have been suggested.

  19. Maruhn-Greiner Maximum of Uranium Fission for Confirmation of Low Energy Nuclear Reactions LENR via a Compound Nucleus with Double Magic Numbers

    Science.gov (United States)

    Hora, H.; Miley, G. H.

    2007-12-01

    One of the most convincing facts about LENR due to deuterons of very high concentration in host metals as palladium is the measurement of the large scale minimum of the reaction probability depending on the nucleon number A of generated elements at A = 153 where a local maximum was measured. This is similar to the fission of uranium at A = 119 where the local maximum follows from the Maruhn-Greiner theory if the splitting nuclei are excited to about MeV energy. The LENR generated elements can be documented any time after the reaction by SIMS or K-shell X-ray excitation to show the very unique distribution with the local maximum. An explanation is based on the strong Debye screening of the Maxwellian deuterons within the degenerate rigid electron background especially within the swimming electron layer at the metal surface or at interfaces. The deuterons behave like neutrals at distances of about 2 picometers. They may form clusters due to soft attraction in the range above thermal energy. Clusters of 10 pm diameter may react over long time probabilities (megaseconds) with Pd nuclei leading to a double magic number compound nucleus which splits like in fission to the A = 153 element distribution.

  20. Method and apparatus for separating uranium isotopes

    International Nuclear Information System (INIS)

    Bernstein, E.R.

    1977-01-01

    A uranium compound in the solid phase (uranium borohydride four) is subjected to radiation of a first predetermined frequency that excites the uranium-235 isotope-bearing molecules but not the uranium-238 isotope-bearing molecules. The compound is simultaneously subjected to radiation of a second predetermined frequency which causes the excited uranium-235 isotope-bearing molecules to chemically decompose but which does not affect the uranium-238 isotope-bearing molecules. Sufficient heat is then applied to the irradiated compound in the solid phase to vaporize the non-decomposed uranium-238 isotope-bearing molecules but not the decomposed uranium-235 isotope-bearing molecules, thereby physically separating the uranium-235 isotope-bearing molecules from the uranium-238 isotope-bearing molecules. The uranium compound sample in the solid phase is deposited or grown in an elongated tube supported within a dewar vessel having a clear optical path tail section surrounded by a coolant. Two sources of radiation are focused on the uranium compound sample. A heating element is attached to the elongated tube to vaporize the irradiated compound

  1. Comparison and analysis of the existing methods of the uranium and its compounds extraction from the materials of the nuclear power

    International Nuclear Information System (INIS)

    Neklyudov, I.M.; Azarenkov, N.A.; Borts, B.V.; Odejchuk, N.P.; Skoromnaya, S.F.; Tkachenko, V.I.

    2008-01-01

    The brief review of the existing methods of the uranium isotope separation as well as for natural uranium enrichment, as for regeneration of the spent nuclear fuel, and also the description of a new intensively developed separation method is given last time - the supercritical fluid extraction in the carbonic acid medium is shown. The comparison of the basic technological indicators of the uranium enrichment by the traditional methods in the supercritical carbonic acid medium is shown. 27 refs.; 18 figs.; 16 tab

  2. Uranium chemistry research unit

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    The initial field of research of this Unit, established in 1973, was the basic co-ordination chemistry of uranium, thorium, copper, cobalt and nickel. Subsequently the interest of the Unit extended to extractive metallurgy relating to these metals. Under the term 'co-ordination chemistry' is understood the interaction of the central transition metal ion with surrounding atoms in its immediate vicinity (within bonding distance) and the influence they have on each other - for example, structural studies for determining the number and arrangement of co-ordinated atoms and spectrophotometric studies to establish how the f electron energy levels of uranium are influenced by the environment. New types of uranium compounds have been synthesized and studied, and the behaviour of uranium ions in non-aqueous systems has also received attention. This work can be applied to the development and study of extractants and new extractive processes for uranium

  3. Method for producing uranium atomic beam source

    International Nuclear Information System (INIS)

    Krikorian, O.H.

    1976-01-01

    A method is described for producing a beam of neutral uranium atoms by vaporizing uranium from a compound UM/sub x/ heated to produce U vapor from an M boat or from some other suitable refractory container such as a tungsten boat, where M is a metal whose vapor pressure is negligible compared with that of uranium at the vaporization temperature. The compound, for example, may be the uranium-rhenium compound, URe 2 . An evaporation rate in excess of about 10 times that of conventional uranium beam sources is produced

  4. Depleted uranium

    International Nuclear Information System (INIS)

    Huffer, E.; Nifenecker, H.

    2001-02-01

    This document deals with the physical, chemical and radiological properties of the depleted uranium. What is the depleted uranium? Why do the military use depleted uranium and what are the risk for the health? (A.L.B.)

  5. LIQUID METAL COMPOSITIONS CONTAINING URANIUM

    Science.gov (United States)

    Teitel, R.J.

    1959-04-21

    Liquid metal compositions containing a solid uranium compound dispersed therein is described. Uranium combines with tin to form the intermetallic compound USn/sub 3/. It has been found that this compound may be incorporated into a liquid bath containing bismuth and lead-bismuth components, if a relatively small percentage of tin is also included in the bath. The composition has a low thermal neutron cross section which makes it suitable for use in a liquid metal fueled nuclear reactor.

  6. Risk limits for boron, silver, titanium, tellurium, uranium and organosilicon compounds in the framework of EU Directive 76/464/EEC

    NARCIS (Netherlands)

    Plassche E van de; Hoop M van de; Posthumus R; Crommentuijn T; CSR; LAC

    1999-01-01

    In the framework of EU Directive 76/464/EEC member states of the European Union have to derive environmental quality standards for the substances mentioned in this directive. For some of these substances no environmental quality standards have up to now been available in the Netherlands. The

  7. Risk limits for boron, silver, titanium, tellurium, uranium and organosilicon compounds in the framework of EU Directive 76/464/EEC

    NARCIS (Netherlands)

    Plassche E van de; Hoop M van de; Posthumus R; Crommentuijn T; CSR; LAC

    1999-01-01

    In het kader van EU richtlijn 76/464 dienen de lidstaten van de Europese Unie milieukwaliteitsnormen af te leiden voor de stoffen die in deze richtlijn genoemd worden. Voor een aantal van deze stoffen waren tot nu toe geen Nederlandse milieukwaliteitsnormen beschikbaar. Daarom heeft het

  8. Studies of layered uranium(VI) compounds. I. High proton conductivity in polycrystalline hydrogen uranyl phosphate tetrahydrate

    International Nuclear Information System (INIS)

    Howe, A.T.; Shilton, M.G.

    1979-01-01

    Hydrogen uranyl phosphate tetrahydrate HUO 2 PO 4 .4H 2 O has a high proton conductivity. The ac conductivity was 0.4 ohm -1 m -1 at 290 0 K measured parallel to the faces of sintered disks of the compound. The activation energy was found to be 31 +- 3 kJ mole -1 . The values of conductivity were between 3 and 10 times lower when measured perpendicular to the disk faces due to preferred orientation of the plate-like crystals. Both the powder and sintered disks are stable in air and insoluble in phosphoric acid solution of pH 2.5. Experiments are described which enable possible grain boundary contributions to the conductivity to be determined in such hydrates. The extrinsic grain boundary contribution to the conductivity was found to be small from experiments in which the pH in a solution cell was varied. The abnormally high bulk H + conductivity thus inferred is attributed primarily to the high concentration of H + , which exists as H 3 O + in the interlamellar hydrogen-bounded network. A Grotthus-type mechanism of conduction is proposed which involves intermolecular transfer steps (hopping) and intramolecular transfer steps, in comparable numbers, the former facilitated by the high concentration of H 3 O + ions in the structure, and the latter most likely facilitated by the high concentration of H-bond vacancies. 8 figures, 1 table

  9. Uranium chemistry: significant advances

    International Nuclear Information System (INIS)

    Mazzanti, M.

    2011-01-01

    The author reviews recent progress in uranium chemistry achieved in CEA laboratories. Like its neighbors in the Mendeleev chart uranium undergoes hydrolysis, oxidation and disproportionation reactions which make the chemistry of these species in water highly complex. The study of the chemistry of uranium in an anhydrous medium has led to correlate the structural and electronic differences observed in the interaction of uranium(III) and the lanthanides(III) with nitrogen or sulfur molecules and the effectiveness of these molecules in An(III)/Ln(III) separation via liquid-liquid extraction. Recent work on the redox reactivity of trivalent uranium U(III) in an organic medium with molecules such as water or an azide ion (N 3 - ) in stoichiometric quantities, led to extremely interesting uranium aggregates particular those involved in actinide migration in the environment or in aggregation problems in the fuel processing cycle. Another significant advance was the discovery of a compound containing the uranyl ion with a degree of oxidation (V) UO 2 + , obtained by oxidation of uranium(III). Recently chemists have succeeded in blocking the disproportionation reaction of uranyl(V) and in stabilizing polymetallic complexes of uranyl(V), opening the way to to a systematic study of the reactivity and the electronic and magnetic properties of uranyl(V) compounds. (A.C.)

  10. Purification of uranium metal

    International Nuclear Information System (INIS)

    Suzuki, Kenji; Shikama, Tatsuo; Ochiai, Akira.

    1993-01-01

    We developed the system for purifying uranium metal and its metallic compounds and for growing highly pure uranium compounds to study their intrinsic physical properties. Uranium metal was zone refined under low contamination conditions as far as possible. The degree of the purity of uranium metal was examined by the conventional electrical resistivity measurement and by the chemical analysis using the inductive coupled plasma emission spectrometry (ICP). The results show that some metallic impurities evaporated by the r.f. heating and other usual metallic impurities moved to the end of a rod with a molten zone. Therefore, we conclude that the zone refining technique is much effective to the removal of metallic impurities and we obtained high purified uranium metal of 99.99% up with regarding to metallic impurities. The maximum residual resistivity ratio, the r.r.r., so far obtained was about 17-20. Using the purified uranium, we are attempting to grow a highly pure uranium-titanium single crystals. (author)

  11. Uranium thiolate complexes

    International Nuclear Information System (INIS)

    Leverd, Pascal C.

    1994-01-01

    This research thesis proposes a new approach to the chemistry of uranium thiolate complexes as these compounds are very promising for various uses (in bio-inorganic chemistry, in some industrial processes like oil desulphurization). It more particularly addresses the U-S bond or more generally bonds between polarizable materials and hard metals. The author thus reports the study of uranium organometallic thiolates (tricyclo-penta-dienic and mono-cyclo-octa-tetraenylic complexes), and of uranium homoleptic thiolates (tetra-thiolate complexes, hexa-thiolate complexes, reactivity of homoleptic thiolate complexes) [fr

  12. [Toxicological evaluation of nanosized colloidal silver, stabilized with polyvinylpyrrolidone. I. Characterization of nanomaterial, integral, hematological parameters, level of thiol compounds and liver cell apoptosis].

    Science.gov (United States)

    Shumakova, A A; Shipelin, V A; Sidorova, Yu S; Trushina, E N; Mustafina, O K; Pridvorova, S M; Gmoshinsky, I V; Khotimchenko, S A

    2015-01-01

    Nano-sized colloidal silver (NCS) is currently one of the most widely used nanomaterials in medicine and consumer’s products. Nanoparticles (NPs) of silver, in addition to the direct exposition through products may expose human via various environmental objects. The aim of the study is to assess the safe doses of silver NP received orally. The investigated NCS contained silver NPs with diameter of 10–60 nm, predominantly with a nearly spherical form stabilized with polyvinylpyrrolidone (PVP). The experiment was performed during 92 days in 5 groups of male Wistar rats (n=15 in each group), receiving a balanced semisynthetic diet. Animal of group 1 (control) received vehicle (deionized water) intragastrically for 30 days and then with food, groups from 2nd to 4th – PVP and groups from 3rd to 5th NCS, in doses respectively, 0.1; 1.0 and 10 mg/kg body weight (b.w.) in terms of silver. The dose of PVP in groups from 2nd to 5th did not differ, amounting to 200 mg/kg b.w. During the experiment, the weight gain, skin condition, activity, stool, cognitive function were assessed. At the end of the feeding period weight of internal organs, intestinal wall permeability to protein macromolecules, liver thiols, standard values of blood erythrocytes, leukocytes and platelets, hepatocyte apoptosis by flow cytometry were studied. These results suggest that in terms of weight gain, lung relative mass, average erythrocyte volume, hemoglobin content and concentration in erythrocytes, the relative proportion of lymphocytes and neutrophils adverse changes have been observed at a dose of 10 mg NPs per kg of b.w. At lower levels of exposure (0.1 and 1.0 mg/kg b.w.) some specific changes were also observed (in terms of thiols pool in liver, cognitive function, relative abundance of monocytes, the number of dead hepatocytes), which, however, did not possess an unambiguous dependence on the dose. Possible mechanisms of the toxic action of the NCS have been discussed.

  13. Electrically Conductive Silver Paste Obtained by Use of Silver Neodecanoate as Precursor

    Science.gov (United States)

    Shen, Longguang; Liu, Jianguo; Zeng, Xiaoyan; Ren, Zhao

    2015-02-01

    An electrically conductive silver paste has been prepared from an organometallic compound, silver neodecanoate, as silver precursor. The precursor was highly soluble in organic solvents and decomposed into metallic silver at low sintering temperatures (writing process, enabling production of silver lines on a substrate. The electrical resistivity of the silver lines was 9 × 10-6 Ω cm after sintering at 115°C for 60 min, 5.8 × 10-6 Ω cm when sintered at 150°C for 60 min, and 3 × 10-6 Ω cm when sintered above 300°C, values which are similar to those of bulk silver. Hence, the prepared paste can be successfully used on flexible substrates such as polymers.

  14. Synthesis and characterization of nanophased silver tungstate

    Indian Academy of Sciences (India)

    nanoparticles were examined with scanning electron microscope (A Lieca Stereoscan. 440 model SEM) at an ... SEM image of rod-like nanocrystalline silver tungstate. Figure 3. ... Thermal analysis shows that the compound is thermally stable ...

  15. Electrolytic recovery of uranium oxides

    International Nuclear Information System (INIS)

    Gurr, W.R.

    1979-01-01

    A method is described for extracting uranium oxide from a solution of one or more uranium compounds, e.g. leach liquors, comprising subjecting the solution to electrolysis utilizing a high current density, e.g. 500 to 4000 amp/m 2 , whereby uranium oxide is formed at the cathode and is recovered. The method is particularly suited to a continuous process using a rotating cathode cell. (author)

  16. The Uranium Chemistry Research Unit

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    The article discusses the research work done at the Uranium Chemistry Research Unit of the University of Port Elizabeth. The initial research programme dealt with fundamental aspects of uranium chemistry. New uranium compounds were synthesized and their chemical properties were studied. Research was also done to assist the mining industry, as well as on nuclear medicine. Special mentioning is made of the use of technetium for medical diagnosis and therapy

  17. Standard test method for the analysis of refrigerant 114, plus other carbon-containing and fluorine-containing compounds in uranium hexafluoride via fourier-transform infrared (FTIR) spectroscopy

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This test method covers determining the concentrations of refrigerant-114, other carbon-containing and fluorine-containing compounds, hydrocarbons, and partially or completely substituted halohydrocarbons that may be impurities in uranium hexafluoride. The two options are outlined for this test method. They are designated as Part A and Part B. 1.1.1 To provide instructions for performing Fourier-Transform Infrared (FTIR) spectroscopic analysis for the possible presence of Refrigerant-114 impurity in a gaseous sample of uranium hexafluoride, collected in a "2S" container or equivalent at room temperature. The all gas procedure applies to the analysis of possible Refrigerant-114 impurity in uranium hexafluoride, and to the gas manifold system used for FTIR applications. The pressure and temperatures must be controlled to maintain a gaseous sample. The concentration units are in mole percent. This is Part A. 1.2 Part B involves a high pressure liquid sample of uranium hexafluoride. This method can be appli...

  18. Uranium exploration

    International Nuclear Information System (INIS)

    De Voto, R.H.

    1984-01-01

    This paper is a review of the methodology and technology that are currently being used in varying degrees in uranium exploration activities worldwide. Since uranium is ubiquitous and occurs in trace amounts (0.2 to 5 ppm) in virtually all rocks of the crust of the earth, exploration for uranium is essentially the search of geologic environments in which geologic processes have produced unusual concentrations of uranium. Since the level of concentration of uranium of economic interest is dependent on the present and future price of uranium, it is appropriate here to review briefly the economic realities of uranium-fueled power generation. (author)

  19. Silver linings.

    Science.gov (United States)

    Bultas, Margaret W; Pohlman, Shawn

    2014-01-01

    The purpose of this interpretive phenomenological study was to gain a better understanding of the experiences of 11 mothers of preschool children with autism spectrum disorder (ASD). Mothers were interviewed three times over a 6 week period. Interviews were analyzed using interpretive methods. This manuscript highlights one particular theme-a positive perspective mothers described as the "silver lining." This "silver lining" represents optimism despite the adversities associated with parenting a child with ASD. A deeper understanding of this side of mothering children with ASD may help health care providers improve rapport, communication, and result in more authentic family centered care. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Yellowcake processing in uranium recovery

    International Nuclear Information System (INIS)

    Paul, J.M.

    1981-01-01

    This information relates to the recovery of uranium from uranium peroxide yellowcake produced by precipitation with hydrogen peroxide. The yellowcake is calcined at an elevated temperature to effect decomposition of the yellowcake to uranium oxide with the attendant evolution of free oxygen. The calcination step is carried out in the presence of a reducing agent which reacts with the free oxygen, thus retarding the evolution of chlorine gas from sodium chloride in the yellowcake. Suitable reducing agents include ammonia producing compounds such as ammonium carbonate and ammonium bicarbonate. Ammonium carbonate and/or ammonium bicarbonate may be provided in the eluant used to desorb the uranium from an ion exchange column

  1. Yellowcake processing in uranium recovery

    Energy Technology Data Exchange (ETDEWEB)

    Paul, J.M.

    1981-10-06

    This information relates to the recovery of uranium from uranium peroxide yellowcake produced by precipitation with hydrogen peroxide. The yellowcake is calcined at an elevated temperature to effect decomposition of the yellowcake to uranium oxide with the attendant evolution of free oxygen. The calcination step is carried out in the presence of a reducing agent which reacts with the free oxygen, thus retarding the evolution of chlorine gas from sodium chloride in the yellowcake. Suitable reducing agents include ammonia producing compounds such as ammonium carbonate and ammonium bicarbonate. Ammonium carbonate and/or ammonium bicarbonate may be provided in the eluant used to desorb the uranium from an ion exchange column.

  2. URANIUM BISMUTHIDE DISPERSION IN MOLTEN METAL

    Science.gov (United States)

    Teitel, R.J.

    1959-10-27

    The formation of intermetallic bismuth compounds of thorium or uranium dispersed in a liquid media containing bismuth and lead is described. A bismuthide of uranium dispersed in a liquid metal medium is formed by dissolving uranium in composition of lead and bismuth containing less than 80% lead and lowering the temperature of the composition to a temperature below the point at which the solubility of uranium is exceeded and above the melting point of the composition.

  3. Critical Amounts of Uranium Compounds

    Science.gov (United States)

    Konopinski, E.; Metropolis, N.; Teller, E.; Woods, L.

    1943-03-19

    The method of calculation of critical masses of oxides and fluorides of U is given. The geometry assumed is a sphere and the calculations hold only in the absence of hydrogenous materials. Calculations are carried out which are applicable to materials containing form 20 to 100% U{sup 235}. (T.R.H.)

  4. Antibacterial Effect of Silver Diamine Fluoride on Cariogenic Organisms.

    Science.gov (United States)

    Lou, Yali; Darvell, Brain W; Botelho, Michael G

    2018-05-01

    To screen the possible antimicrobial activity of a range of clinically used, silver-based compounds on cariogenic organisms: silver diamine fluoride (SDF), silver fluoride, and silver nitrate. Preliminary screening disk-diffusion susceptibility tests were conducted on Mueller-Hinton agar plates inoculated with Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces naeslundii, organisms known to be cariogenic. In order to identify which component of the silver compounds was responsible for any antibacterial (AB) effect, and to provide controls, the following were also investigated at high and low concentrations: sodium fluoride, ammonium fluoride, ammonium chloride, sodium fluoride, sodium chloride, and sodium nitrate, as well as deionized water as control. A volume of 10 pL of a test solution was dispensed onto a paper disk resting on the inoculated agar surface, and the plate incubated anaerobically at 37°C for 48 hours. The zones of inhibition were then measured. Silver diamine fluoride, silver fluoride, silver nitrate, and ammonium fluoride had significant AB effect (p effect at low concentration; the remaining other compounds had no effect. Silver ions appear to be the principal AB agent at both high and low concentration; fluoride ions only have an AB effect at high concentration, while ammonium, nitrate, chloride and sodium ions have none. The anticaries effect of topical silver solutions appears restricted to that of the silver ions. Silver compounds, such as SDF, silver fluoride, and silver nitrate have AB effect against cariogenic organisms and these may have clinical impact in arresting or preventing dental decay. Sodium fluoride did not have AB effect under the conditions tested.

  5. Investigation of the synergic effect of some neutral organophosphoric compounds on the extraction of uranium from phosphoric acid solutions by D1-(2-Ethyl Hexyl) phosphoric acid

    International Nuclear Information System (INIS)

    Stas, J.; Khorfan, S.; Koudsi, Y.

    1998-05-01

    The extraction of uranium (VI) from pure phosphoric acid media by D2EHPA/Kerosene has been studied. The mechanism of the extraction was found as follows: The logarithm of the equilibrium constant of the extraction (LogKex) was found (3.06), (3.32), (3.24), (3.3) for the following phosphoric acid concentrations respectively (1), (2), (3), (4) Mol/1, and the enthalpy change DELTA H was found (-100.68 kj/mol). (-76 kj/mol) for (1), (2) mol/1 phosphoric acid concentrations. The synergic effect of TOPO, TBP, and TBPI with DEHPA have been studied during the extraction of uranium from pure phosphoric acid and Syrian commercial phosphoric acid. The synergic effect increases as follows: TBP< TBPI<< TOPO (In pure phosphoric acid), TBPI approx TBP<< TOPO (In Syrian commercial phosphoric acid). The difficulty of extracting uranium (VI) from Syrian commercial phosphoric acid in comparison with pure phosphoric acid is due to the presence of several impurities capable of complexing uranium, and a small amounts of solid and organic matters, all these are factors which reduce the distribution coefficient of uranium. (Author)

  6. Russell-Silver syndrome

    Science.gov (United States)

    Silver-Russell syndrome; Silver syndrome; RSS; Russell-Silver syndrome ... One in 10 children with this syndrome has a problem involving chromosome 7. In other people with the syndrome, it may affect chromosome 11. Most of the time, it ...

  7. Mathematical simulation of the amplification of 1790-nm laser radiation in a nuclear-excited He - Ar plasma containing nanoclusters of uranium compounds

    Science.gov (United States)

    Kosarev, V. A.; Kuznetsova, E. E.

    2014-02-01

    The possibility of applying dusty active media in nuclearpumped lasers has been considered. The amplification of 1790-nm radiation in a nuclear-excited dusty He - Ar plasma is studied by mathematical simulation. The influence of nanoclusters on the component composition of the medium and the kinetics of the processes occurring in it is analysed using a specially developed kinetic model, including 72 components and more than 400 reactions. An analysis of the results indicates that amplification can in principle be implemented in an active laser He - Ar medium containing 10-nm nanoclusters of metallic uranium and uranium dioxide.

  8. Synthesis and characterization of nanometer sized thermoelectric lead-antimony-silver-tellurium compounds and related materials; Synthese und Charakterisierung nanoskaliger Thermoelektrika der LAST (Lead-Antimony-Silver-Tellurium)-Familie und verwandter Verbindungen

    Energy Technology Data Exchange (ETDEWEB)

    Petri, Denis

    2012-09-10

    The present dissertation deals with different variants of synthesis and processing of nanocrystalline composites of various thermoelectric compounds based on lead telluride including LAST-m (AgPb{sub m}SbTe{sub m+2}), LASTT-m-x (AgPb{sub m-x}Sn{sub x}SbTe{sub m+2}), LABST-m-x (AgPb{sub m}Sb{sub 1-x}Bi{sub x}Te{sub m+2}), doped LAST-m and (PbTe){sub m}(M{sup 15}{sub 2}Te{sub 3}) and the characterization thereof. A new route of manufacturing nanocrystalline composites was developed. The so called co-ball milling-route includes the synthesis of bi- or multinary compounds by conventional solid state melting methods followed by combined milling of appropriate amounts in a planetary ball mill; a process related to the widely used mechanical alloying of elemental powders. The as produced powders were shortly annealed for one hour and a.erwards compacted either at room temperature followed by pressureless sintering or combined application of high pressure and elevated temperatures via spark-plasma-sintering or short-term-sintering. The ball milling yielded micron-sized agglomerates consisting of crystallites with diameters ranging from 10 to 50 nm. These crystallites exhibited complicated internal nanostructures severe crystal defects as a consequence of the high energy processing. During short-term annealing some grain coarsening occured and the crystal defects partly healed, which was confirmed by TEM and HRTEM investigations as well as profile analysis of XRD powder pattern. Local EDX-analysis showed different compositions at every point as a consequence of synthesis and decomposition of the compounds. Measurements of thermopower, electrical and thermal conductivity were carried out and the values of the figure of merit ZT and the powerfactor were calculated. In general the compounds exhibited larger thermopower than corresponding bulk materials, which might be attributed to energy filtering of charge carriers at partly oxidized grain boundaries. Due to enhanced phonon

  9. Medical effects of internal contamination with uranium.

    Science.gov (United States)

    Duraković, A

    1999-03-01

    The purpose of this work is to present an outline of the metabolic pathways of uranium isotopes and compounds, medical consequences of uranium poisoning, and an evaluation of the therapeutic alternatives in uranium internal contamination. The chemical toxicity of uranium has been recognized for more than two centuries. Animal experiments and human studies are conclusive about metabolic adverse affects and nephro- toxicity of uranium compounds. Radiation toxicity of uranium isotopes has been recognized since the beginning of the nuclear era, with well documented evidence of reproductive and developmental toxicity, as well as mutagenic and carcinogenic consequences of uranium internal contamination. Natural uranium (238U), an alpha emitter with a half-life of 4.5x10(9) years, is one of the primordial substances of the universe. It is found in the earth's crust, combined with 235U and 234U, alpha, beta, and gamma emitters with respective half-lives of 7.1x10(8) and 2.5x10(5) years. A special emphasis of this paper concerns depleted uranium. The legacy of radioactive waste, environmental and health hazards in the nuclear industry, and, more recently, the military use of depleted uranium in the tactical battlefield necessitates further insight into the toxicology of depleted uranium. The present controversy over the radiological and chemical toxicity of depleted uranium used in the Gulf War warrants further experimental and clinical investigations of its effects on the biosphere and human organisms.

  10. Chapter 1. General information about uranium. 1.3. Uranium ores

    International Nuclear Information System (INIS)

    Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

    2012-01-01

    The uranium ores were described. It was found that uranium ores and natural mineral formations containing uranium and its compounds, can be found in concentrations that are technically possible for industrial utilization and which are economically profitable. It was defined that oxidation levels of uranium minerals have an impact on their reprocessing technology and behavior in hydrometallurgical re partition. It was found that the chemical composition of ores has a decisive importance during selection of their reprocessing method.

  11. Czechoslovak uranium

    International Nuclear Information System (INIS)

    Pluskal, O.

    1992-01-01

    Data and knowledge related to the prospecting, mining, processing and export of uranium ores in Czechoslovakia are presented. In the years between 1945 and January 1, 1991, 98,461.1 t of uranium were extracted. In the period 1965-1990 the uranium industry was subsidized from the state budget to a total of 38.5 billion CSK. The subsidies were put into extraction, investments and geologic prospecting; the latter was at first, ie. till 1960 financed by the former USSR, later on the two parties shared costs on a 1:1 basis. Since 1981 the prospecting has been entirely financed from the Czechoslovak state budget. On Czechoslovak territory uranium has been extracted from deposits which may be classified as vein-type deposits, deposits in uranium-bearing sandstones and deposits connected with weathering processes. The future of mining, however, is almost exclusively being connected with deposits in uranium-bearing sandstones. A brief description and characteristic is given of all uranium deposits on Czechoslovak territory, and the organization of uranium mining in Czechoslovakia is described as is the approach used in the world to evaluate uranium deposits; uranium prices and actual resources are also given. (Z.S.) 3 figs

  12. Structural and magnetic properties of some pseudo-binary and ternary compounds at high curie temperature prepared in the systems: -) rare earth (Nd, Sm) iron hydrogen, -) gadolinium iron aluminium, and -) uranium iron or cobalt silicon or germanium; Proprietes structurales et magnetiques de quelques composes pseudobinaires et ternaires ferromagnetiques a temperature de curie elevee prepares dans les systemes: -) terres rares Nd Sm fer hydrogene, -) gadolinium fer aluminium, and -) uranium fer ou cobalt silicium ou germanium

    Energy Technology Data Exchange (ETDEWEB)

    Berlureau, T

    1991-07-15

    This work highlights the importance of crystal and chemical studies for understanding the magnetic properties of systems as complex as inter-metallic compounds involving rare-earth elements, uranium, silicon or germanium. With a view of finding new compounds with high Curie temperature and strong magneto-crystal anisotropy, it appears that uranium compounds such as UFe{sub 10}Si{sub 2}, UCo{sub 10}Si{sub 2}, U(Fe{sub 10-x}Co{sub x})Si{sub 2} and U{sub 2}M{sub 17-y}X{sub y} where M is Fe or Co and Y is Si or Ge, are interesting because of the 5f orbital that can form bands through direct overlapping and can link itself very strongly with orbitals of nearby atoms.

  13. Radiation protection program applied to occupationally exposed individuals at the IPEN/CNEN-SP pilot plant in the 1980s for natural uranium compounds

    International Nuclear Information System (INIS)

    Silva, Teresinha de Moraes da; Sordi, Gian Maria A.A.; Vasques, Francisco Mário Feijó

    2017-01-01

    The work evidences the chemical processing of natural uranium from the yellowcake phase to the production of UF 6 natural uranium hexafluoride, a process carried out at the IPEN/CNEN-SP pilot plant. Radiation protection management was intended to monitor occupationally exposed individuals - IOEs, the workplace and the environment. An individual monitoring program for IOEs was developed for both external irradiation and incorporation of radioactive material. The IOEs were monitored externally with film-type dosimeters and the in vitro method was applied internally for urine analysis. For the workplace the monitoring program for equipment and floors was developed, determining the exposure rate from the process equipment, surface contamination expressed in Bq.cm -2 in equipment and floors, complemented by the air monitoring program both for the worker as well as for the workplace. Cellulose filters with aerodynamic diameter of 0.3 micron to 8.0 micron were used

  14. Uranium - the element: its occurrence and uses

    International Nuclear Information System (INIS)

    Awan, I. Z.

    2015-01-01

    Uranium metal and its compounds have been of great interest to physicists and chemists due to its use for both civil and military applications, e.g. production of electricity, use in the medical field and for making nuclear weapons. This review paper describes the occurrence, chemistry and metallurgy of the element 'uranium', its conversion to stable compounds such as yellow cake, uranium tetrafluoride and uranium hexafluoride and the enrichment technologies and uses for both civil and military purposes. The paper is meant for ready reference for students and teachers in connection with the recent spate of interest shown in nuclear power generation in Pakistan and abroad. (author)

  15. Applied internal dosimetry staff exposed to Uranium

    International Nuclear Information System (INIS)

    Trotta, Marisa V.; Arguelles, Maria G.

    2009-01-01

    Dosimetric calculations are performed in order to estimate the quantity of a radionuclide that is incorporated by a worker. Urine determinations of activity and mass of uranium are made in the laboratory of Personal and Area Dosimetry. The paper presents reference values concerning the activity excreted in urine due to the incorporation of uranium compounds. The compounds analyzed are natural uranium and uranium enriched to 20 %, both soluble and insoluble. According to the limits allowed for the incorporation of uranium compounds of Type F and M, we verify that the times of monitoring and the detection limits of the equipment used to determine the activity are appropriate. On the other hand, the S-type compounds determination in urine is useful in cases of accidental incorporations (above the ALI) as a first and quick estimate; MDA (0.017 Bq / L) does not allow detection in routine monitoring; measurement in lungs, and faeces should be included. (author)

  16. Ligand influences on properties of uranium coordination complexes. Structure, reactivity, and spectroscopy

    International Nuclear Information System (INIS)

    Kosog, Boris

    2012-01-01

    In this thesis several different aspects of uranium chemistry are presented. It was shown that terminal uranium(V) oxo and imido complexes [(( R ArO) 3 tacn)U V (O)] and [(( R ArO) 3 tacn)U V (NSiMe 3 )] (R = t Bu, Ad) can be oxidized by silver(I) hexafluoro-antimonate to the uranium(VI) oxo and imido complexes [(( R ArO) 3 tacn)U VI (O)]SbF 6 and [(( R ArO) 3 tacn)U VI (NSiMe 3 )]SbF 6 . While for the t Bu-derivative of the oxo complex an equatorial coordination is observed due to stabilization by the inverse trans-influence, normal axial coordination is observed for the Ad-derivative and both imido complexes. The inverse trans-influence was thus proven to be a key factor for the coordination mode of a terminal ligand on high valent uranium complexes. L III XANES was shown to be a great tool for the determination of oxidation states of uranium complexes. Therefore, a series of uranium complexes in all stable oxidation states for uranium, +III to +VI was prepared, and their spectra analyzed. All compounds bear only O-donor ligands in addition to the chlating trisaryloxide-tacn-ligand. A separation of 1.5 to 3 eV in the white line energy is observed between the different oxidation states. This series can be used as reference for compounds, where oxidation state assignment is not obvious, such as a ketyl radical complex [(( t-Bu Ar)O 3 tacn)U(O-C( t-Bu Ph) 2 .- )]. For this complex, the oxidation state of +IV could be assigned. Moreover, a series of isostructural uranium(IV) complexes was prepared. The influence of different ligands according to the spectrochemical series on the electronic and magnetic properties could be shown using UV/vis/NIR spectroscopy and variable temperature SQUID measurements. Calculations of uranium L III XANES spectra show a variation in the shape of the spectra and thus high resolution PFY-XANES would be a great tool to determine the electronic influence of these different axial ligands. Using the single N-anchored ligand system, the first

  17. Uranium dioxide calcining apparatus

    International Nuclear Information System (INIS)

    Cole, E.A.; Peterson, R.S.

    1978-01-01

    This invention relates to an improved continuous calcining apparatus for consistently and controllably producing from calcinable reactive solid compounds of uranium, such as ammonium diuranate, uranium dioxide (UO 2 ) having an oxygen to uranium ratio of less than 2.2. The apparatus comprises means at the outlet end of a calciner kiln for receiving hot UO 2 , means for cooling the UO 2 to a temperature of below 100 deg C and conveying the cooled UO 2 to storage or to subsequent UO 2 processing apparatus where it finally comes into contact with air, the means for receiving cooling and conveying being sealed to the outlet end of the calciner and being maintained full of UO 2 and so operable as to exclude atmospheric oxygen from coming into contact with any UO 2 which is at elevated temperatures where it would readily oxidize, without the use of extra hydrogen gas in said means. (author)

  18. Hydrogeochemical and stream sediment reconnaissance basic data for Silver City Quadrangle, New Mexico; Arizona

    International Nuclear Information System (INIS)

    1981-01-01

    Field and laboratory data are presented for 405 water samples and 736 sediment samples from the Silver City Quadrangle, New Mexico; Arizona. Uranium values have been reported by Los Alamos National Laboratory in Report GJBX-69(78). The samples were collected by Los Alamos National Laboratory; laboratory analysis and data reporting were performed by the Uranium Resource Evaluation Project at Oak Ridge, Tennessee

  19. Uranium exploration of Samar Island

    International Nuclear Information System (INIS)

    Santos, G. Jr.

    1979-02-01

    Uranium exploration is being undertaken to meet the requirements of the Philippine Nuclear Power Plant-1 (PNPP-1) programmed to operate in 1982, for about 140 metric tons annually or 2664 MT of U 3 O 8 up to the year 2000. Samar was chosen as the survey pilot project and the method used was a geochemical reconnaissance or low density observation survey to delineate broad areas where follow-up uranium surveys may be undertaken. Stream sediments or surface waters were collected at each sampling point at a density of one sample per 20-25 sq. km. The conductance and pH of the water were measured with a conductivity meter and pH respectively. Radioactivity was determined using a portable scintillometer. The stream sediment and heavy mineral samples were analyzed for uranium (U), copper (CCu), lead (Pb), zinc (Zn), manganese (Mn), silver (Ag), cobalt (Co), nickel (Ni). Water samples were analyzed for uranium only. The solid samples were digested in an acid mixture of 85% concentrated nitric acid and 15% concentrated hydrochloric acid, and the leachable uranium was determined using a fluorimeter. The detection limits for uranium were 0.3 ppb and 0.3 ppm for water and solid samples, respectively. Analysis for Cu, Pb, Zn, Mn, Ag, Co, and Ni were done by Atomic Absorption Spectrophotometry using the same leaching solution prepared for uranium analysis. Over 9000 determinations were done on nearly 1600 samples. The survey delineated at least two areas where follow-up surveys for uranium are warranted. These areas are the San Isidro - Catarman in Northwestern Samar, and the vicinity of Bagacay mines in Central Samar

  20. Synthesis and reactivity of triscyclopentadienyl uranium (III) and (IV) complexes

    International Nuclear Information System (INIS)

    Berthet, J.C.

    1992-01-01

    The reactions of (RC 5 H 4 ) 3 U with R=trimethylsilylcyclopentadienyl or tertiobutylcyclopentadienyl are studied for the synthesis of new uranium organometallic compounds. Reactions with sodium hydride are first described uranium (III) anionic hydrides obtained are oxidized for synthesis of stable uranium (IV) organometallic hydrides. Stability of these compounds is discussed. Reactivity of these uranium (III) and (IV) hydrides are studied. Formation of new binuclear compounds with strong U-O and U-N bonds is examined and crystal structure are presented. Monocyclooctatetraenylic uranium complexes are also investigated

  1. Uranium ores

    International Nuclear Information System (INIS)

    Poty, B.; Roux, J.

    1998-01-01

    The processing of uranium ores for uranium extraction and concentration is not much different than the processing of other metallic ores. However, thanks to its radioactive property, the prospecting of uranium ores can be performed using geophysical methods. Surface and sub-surface detection methods are a combination of radioactive measurement methods (radium, radon etc..) and classical mining and petroleum prospecting methods. Worldwide uranium prospecting has been more or less active during the last 50 years, but the rise of raw material and energy prices between 1970 and 1980 has incited several countries to develop their nuclear industry in order to diversify their resources and improve their energy independence. The result is a considerable increase of nuclear fuels demand between 1980 and 1990. This paper describes successively: the uranium prospecting methods (direct, indirect and methodology), the uranium deposits (economical definition, uranium ores, and deposits), the exploitation of uranium ores (use of radioactivity, radioprotection, effluents), the worldwide uranium resources (definition of the different categories and present day state of worldwide resources). (J.S.)

  2. Uranium market

    International Nuclear Information System (INIS)

    Rubini, L.A.; Asem, M.A.D.

    1990-01-01

    The historical development of the uranium market is present in two periods: The initial period 1947-1970 and from 1970 onwards, with the establishment of a commercial market. The world uranium requirements are derived from the corresponding forecast of nuclear generating capacity, with, particular emphasis to the brazilian requirements. The forecast of uranium production until the year 2000 is presented considering existing inventories and the already committed demand. The balance between production and requirements is analysed. Finally the types of contracts currently being used and the development of uranium prices in the world market are considered. (author)

  3. Uranium enrichment

    International Nuclear Information System (INIS)

    1990-01-01

    This report looks at the following issues: How much Soviet uranium ore and enriched uranium are imported into the United States and what is the extent to which utilities flag swap to disguise these purchases? What are the U.S.S.R.'s enriched uranium trading practices? To what extent are utilities required to return used fuel to the Soviet Union as part of the enriched uranium sales agreement? Why have U.S. utilities ended their contracts to buy enrichment services from DOE?

  4. Improvements made in the methods of purifying uranium compounds and in the production of uranium metal at the Bouchet plant; Ameliorations apportees aux procedes de purification des composes d'uranium et a la fabrication de l'uranium metal a l'usine du Bouchet

    Energy Technology Data Exchange (ETDEWEB)

    Decrop, J; Delange, M; Holder, J; Huet, H; Sauteron, J; Vertes, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    We intend to chart the development of the techniques used at the Bouchet plant since the First International Conference held in Geneva in 1955. During that Conference, the methods adopted at that time were described by B. GOLDSCHMIDT and P. VERTES. Generally speaking, the development since that time has been governed by the following factors: 1- Conversion to a mass-production scale: The metal output, which amounted to approximately 10 tons in 1952, practically doubled each year, reaching successive figures of 80 tons in 1955, 160 tons in 1956 and 300 tons in 1957. At this very moment the output capacity of the plant is approaching its maximum, set at 500 tons/year, which it will reach at the end of the year. Beyond this output figure, the work will be carried on by the second French uranium production plant, which is now being erected at Narbonne. 2- Gradual abandoning of ore treatment, resulting from the decentralization of the duties performed by the CEA; The Bouchet Plant had, as a matter of fact, the first French treatment facilities, operating on the basis of 10 to 20 tons of ore per day. This ore, first concentrated at the production site proper by means of physical or physico-chemical methods to at least a 2 per cent uranium content, was sufficiently valuable to warrant quite well the cost involved in shipping it. However, the increase in the production schedules led to the treatment of ores of lower and lower grades, and it became more profitable to proceed with the chemicalating of these low-grade ores at the site after more or less thorough grading and, if necessary, preconcentration. As a result, the Bouchet plant scarcely ever receives uranium ores; on the contrary, the mining companies send their chemical concentrates, uranous phosphate and then sodium uranate from the Gueugnon Works in Saone-et-Loire since 1955; magnesium uranate from the Ecarpiere Works in Vendee since the beginning of 1957 and, very soon, products from the works which are now being

  5. Airborne uranium, its concentration and toxicity in uranium enrichment facilities

    International Nuclear Information System (INIS)

    Thomas, J.; Mauro, J.; Ryniker, J.; Fellman, R.

    1979-02-01

    The release of uranium hexafluoride and its hydrolysis products into the work environment of a plant for enriching uranium by means of gas centrifuges is discussed. The maximum permissible mass and curie concentration of airborne uranium (U) is identified as a function of the enrichment level (i.e., U-235/total U), and chemical and physical form. A discussion of the chemical and radiological toxicity of uranium as a function of enrichment and chemical form is included. The toxicity of products of UF 6 hydrolysis in the atmosphere, namely, UO 2 F 2 and HF, the particle size of toxic particulate material produced from this hydrolysis, and the toxic effects of HF and other potential fluoride compounds are also discussed. Results of an investigation of known effects of humidity and temperature on particle size of UO 2 F 2 produced by the reaction of UF 6 with water vapor in the air are reported. The relationship of the solubility of uranium compounds to their toxic effects was studied. Identification and discussion of the standards potentially applicable to airborne uranium compounds in the working environment are presented. The effectiveness of High Efficiency Particulate (HEPA) filters subjected to the corrosive environment imposed by the presence of hydrogen fluoride is discussed

  6. Alkyne-Azide Cycloaddition Catalyzed by Silver Chloride and “Abnormal” Silver N-Heterocyclic Carbene Complex

    Directory of Open Access Journals (Sweden)

    Aldo I. Ortega-Arizmendi

    2013-01-01

    Full Text Available A library of 1,2,3-triazoles was synthesized from diverse alkynes and azides using catalytic amounts of silver chloride instead of copper compounds. In addition, a novel “abnormal” silver N-heterocyclic carbene complex was tested as catalyst in this process. The results suggest that the reaction requires only 0.5% of silver complex, affording 1,2,3-triazoles in good yields.

  7. Anticorrosion protection of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Goncharov, Ivan D.; Kazakovskaya, Tatiana; Tukmakov, Victor; Shapovalov, Vyacheslav [Russian Federal Nuclear Center-VNIIEF, 37, Mira Ave., RU-607190 Sarov (Nizhnii Gorod), 010450 (Russian Federation)

    2004-07-01

    Uranium in atmospheric conditions is non-stable. Sloughing products are being generated on its surface during storage or use. These corrosion products make many difficulties because of necessity to provide personnel safety. Besides, uranium corrosion may cause damage in parts. The first works devoted to uranium corrosion were performed in the framework of the USA Manhattan Project in the early forties of last century. Various methods of uranium protection were investigated, among them the galvanic one was the most studied. Later on the galvanic technology was patented. The works on this problem remains urgent up to the present time. In Russia, many methods of uranium corrosion protection, mainly against atmospheric corrosion, were tried on. In particular, such methods as diffusion zinc and paint coating were investigated. In the first case, a complex intermetallic U-Zn compound was formed but its protection was not reliable enough, this protection system was inconvenient and uncertain and that is why an additional paint coating was necessary. In the case of paint coatings another problem appeared. It was necessary to find such a coating where gas-permeability would prevail over water-permeability. Otherwise significant uranium corrosion occurs. This circumstance together with low mechanical resistance of paint coatings does not allow to use paint coating for long-term protection of uranium. Currently, there are following methods of uranium protection: ion-plasma, galvanic and thermo-vacuum annealing. These are described in this paper. In the end the issue of corrosion protection in reactor core zones is addressed. Here the greatest difficulties are caused when enriched uranium heated up to 500 deg. C needs anticorrosion protection. In this case various metal coatings are not reliable because of brittle inter-metallide formation. The reliable protection may be provided only up to the temperature plus 400 - 500 deg. C with the help of galvanic copper coating since

  8. Anticorrosion protection of uranium

    International Nuclear Information System (INIS)

    Goncharov, Ivan D.; Kazakovskaya, Tatiana; Tukmakov, Victor; Shapovalov, Vyacheslav

    2004-01-01

    Uranium in atmospheric conditions is non-stable. Sloughing products are being generated on its surface during storage or use. These corrosion products make many difficulties because of necessity to provide personnel safety. Besides, uranium corrosion may cause damage in parts. The first works devoted to uranium corrosion were performed in the framework of the USA Manhattan Project in the early forties of last century. Various methods of uranium protection were investigated, among them the galvanic one was the most studied. Later on the galvanic technology was patented. The works on this problem remains urgent up to the present time. In Russia, many methods of uranium corrosion protection, mainly against atmospheric corrosion, were tried on. In particular, such methods as diffusion zinc and paint coating were investigated. In the first case, a complex intermetallic U-Zn compound was formed but its protection was not reliable enough, this protection system was inconvenient and uncertain and that is why an additional paint coating was necessary. In the case of paint coatings another problem appeared. It was necessary to find such a coating where gas-permeability would prevail over water-permeability. Otherwise significant uranium corrosion occurs. This circumstance together with low mechanical resistance of paint coatings does not allow to use paint coating for long-term protection of uranium. Currently, there are following methods of uranium protection: ion-plasma, galvanic and thermo-vacuum annealing. These are described in this paper. In the end the issue of corrosion protection in reactor core zones is addressed. Here the greatest difficulties are caused when enriched uranium heated up to 500 deg. C needs anticorrosion protection. In this case various metal coatings are not reliable because of brittle inter-metallide formation. The reliable protection may be provided only up to the temperature plus 400 - 500 deg. C with the help of galvanic copper coating since

  9. Preconcentration of silver as silver xanthate on activated carbon

    International Nuclear Information System (INIS)

    Ramadevi, P.; Naidu, U.V.; Naidu, G.R.K.

    1988-01-01

    Silver from aqueous solution was preconcentrated by adsorption on activated carbon as silver xanthate. Factors influencing the adsorption of silver were studied. Optimum conditions for the preconcentration of silver were established. (author) 9 refs.; 3 tabs

  10. Heteropolyhedral silver compounds containing the polydentate ligand N,N,O-E-[6-(hydroxyimino)ethyl]-1,3,7-trimethyllumazine. Preparation, spectral and XRD structural study and AIM calculations.

    Science.gov (United States)

    Jiménez-Pulido, Sonia B; Hueso-Ureña, Francisco; Fernández-Liencres, M Paz; Fernández-Gómez, Manuel; Moreno-Carretero, Miguel N

    2013-01-14

    The oxime derived from 6-acetyl-1,3,7-trimethyllumazine (1) ((E-6-(hydroxyimino)ethyl)-1,3,7-trimethylpteridine-2,4(1H,3H)-dione, DLMAceMox) has been prepared and its molecular and crystal structure determined from spectral and XRD data. The oxime ligand was reacted with silver nitrate, perchlorate, thiocyanate, trifluoromethylsulfonate and tetrafluoroborate to give complexes with formulas [Ag(2)(DLMAceMox)(2)(NO(3))(2)](n) (2), [Ag(2)(DLMAceMox)(2)(ClO(4))(2)](n) (3), [Ag(2)(DLMAceMox)(2)(SCN)(2)] (4), [Ag(2)(DLMAceMox)(2)(CF(3)SO(3))(2)(CH(3)CH(2)OH)]·CH(3)CH(2)OH (5) and [Ag(DLMAceMox)(2)]BF(4) (6). Single-crystal XRD studies show that the asymmetrical residual unit of complexes 2, 3 and 5 contains two quite different but connected silver centers (Ag1-Ag2, 2.9-3.2 Å). In addition to this, the Ag1 ion displays coordination with the N5 and O4 atoms from both lumazine moieties and a ligand (nitrato, perchlorato or ethanol) bridging to another disilver unit. The Ag2 ion is coordinated to the N61 oxime nitrogens, a monodentate and a (O,O)-bridging nitrato/perchlorato or two monodentate O-trifluoromethylsulfonato anions. The coordination polyhedra can be best described as a strongly distorted octahedron (around Ag1) and a square-based pyramid (around Ag2). The Ag-N and Ag-O bond lengths range between 2.22-2.41 and 2.40-2.67 Å, respectively. Although the structure of 4 cannot be resolved by XRD, it is likely to be similar to those described for 2, 3 and 5, containing Ag-Ag units with S-thiocyanato terminal ligands. Finally, the structure of the tetrafluoroborate compound 6 is mononuclear with a strongly distorted tetrahedral AgN(4) core (Ag-N, 2.27-2.43 Å). Always, the different Ag-N distances found clearly point to the more basic character of the oxime N61 nitrogen atom when compared with the pyrazine N5 one. A topological analysis of the electron density within the framework provided by the quantum theory of atoms in molecules (QTAIM) using DFT(M06L) levels of

  11. Estimation of silver in Ag-meta kaolinite by neutron activation

    International Nuclear Information System (INIS)

    Daniels, E.A.; Rao, S.M.

    1981-01-01

    The present work is based on the neutron activation of Ag-meta kaolinite for the determination of its silver content from the β-activity of the compound using standard tables which showed the percentage of silver in mixtures of silver nitrate and meta kaolinite of known composition against β-activity of the mixture activated under identical conditions. (author)

  12. Uranium mining

    International Nuclear Information System (INIS)

    Lange, G.

    1975-01-01

    The winning of uranium ore is the first stage of the fuel cycle. The whole complex of questions to be considered when evaluating the profitability of an ore mine is shortly outlined, and the possible mining techniques are described. Some data on uranium mining in the western world are also given. (RB) [de

  13. [UO{sub 2}Cl{sub 2}(phen){sub 2}], a simple uranium(VI) compound with a significantly bent uranyl unit (phen=1,10-phenanthroline)

    Energy Technology Data Exchange (ETDEWEB)

    Schoene, Sebastian; Radoske, Thomas; Maerz, Juliane; Stumpf, Thorsten; Patzschke, Michael; Ikeda-Ohno, Atsushi [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Dresden (Germany)

    2017-10-04

    A simple synthesis based on UO{sub 2}Cl{sub 2}.n H{sub 2}O and 1,10-phenanthroline (phen) resulted in the formation of a new uranyl(VI) complex [UO{sub 2}Cl{sub 2}(phen){sub 2}] (1), revealing a unique dodecadeltahedron coordination geometry around the uranium center with significant bending of the robust linear arrangement of the uranyl (O-U-O) unit. Quantum chemical calculations on complex 1 indicated that the weak but distinct interactions between the uranyl oxygens and the adjacent hydrogens of phen molecules play an important role in forming the dodecadeltahedron geometry that fits to the crystal structure of 1, resulting in the bending the uranyl unit. The uranyl oxygens in 1 are anticipated to be activated as compared with those in other linear uranyl(VI) compounds. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. U uranium. Suppl. Vol. D3

    International Nuclear Information System (INIS)

    Haug, H.O.

    1982-01-01

    This volume of the uranium series of the Gmelin handbook deals with the anion exchange of uranium. Compounds of the valence states of III, IV, V and VI of uranium in halide, nitrate, sulfate, phosphate, and carbonate media as well as in media containing organic complexing agents are treated. The literature cited covers the period from about 1947 to the end of 1980. (RB) [de

  15. Molybdenum from uranium solutions

    International Nuclear Information System (INIS)

    Gardner, H.E.

    1981-01-01

    A method of removing molybdenum from a uranium bearing solution is claimed. It comprises adding sufficient reactive lead compound to supply at least 90 percent of the stoichiometric quantity of lead ion required to fully react with the molybdenum present to form insoluble lead molybdate and continuing the reaction with agitation until the desired percentage of the molybdenum present has reacted with the lead ion

  16. Uranium enrichment

    International Nuclear Information System (INIS)

    1989-01-01

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

  17. Uranium resources

    International Nuclear Information System (INIS)

    1976-01-01

    This is a press release issued by the OECD on 9th March 1976. It is stated that the steep increases in demand for uranium foreseen in and beyond the 1980's, with doubling times of the order of six to seven years, will inevitably create formidable problems for the industry. Further substantial efforts will be needed in prospecting for new uranium reserves. Information is given in tabular or graphical form on the following: reasonably assured resources, country by country; uranium production capacities, country by country; world nuclear power growth; world annual uranium requirements; world annual separative requirements; world annual light water reactor fuel reprocessing requirements; distribution of reactor types (LWR, SGHWR, AGR, HWR, HJR, GG, FBR); and world fuel cycle capital requirements. The information is based on the latest report on Uranium Resources Production and Demand, jointly issued by the OECD's Nuclear Energy Agency (NEA) and the International Atomic Energy Agency. (U.K.)

  18. Uranium and lanthanide complexes with the 2-mercapto benzothiazolate ligand: Evidence for a specific covalent binding site in the differentiation of isostructural lanthanide(III) and actinide(III) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Roger, M.; Arliguie, T.; Thuery, P.; Ephritikhine, M. [CEA Saclay, DSM, DRECAM, Serv Chim Mol, CNRS URA 331, F-91191 Gif Sur Yvette, (France); Belkhiri, L. [Univ Mentouri Constantine, Fac Sci, Dept Chim, Lab Chim Mol LACMOM, Constantine 25017, (Algeria); Boucekkine, A. [Univ Rennes 1, CNRS, UMR Sci Chim Rennes 6226, F-35042 Rennes, (France)

    2008-07-01

    Treatment Of [U(Cp*){sub 2}Cl{sub 2}] with KSBT in THF gave [U(Cp*){sub 2}(SBT){sub 2}], which exhibits the usual bent sandwich configuration in the solid state with the two SBT ligands adopting the bidentate ligation mode. The mono-cyclopentadienyl compound [U(Cp*)(SBT){sub 3}] was synthesized by reaction of [U(Cp*)(BH{sub 4}){sub 3}] with KSBT in THF, and its reduction with potassium amalgam in the presence of 18-crown-6 afforded the corresponding anionic complex [K(18-crown-6)(THF){sub 2}][U(Cp*)(SBT){sub 3}]. The lanthanide analogues [K(THF){sub 2}Ln(Cp*)(SBT){sub 3}] were obtained by treating [Ln(BH{sub 4}){sub 3}(THF){sub 3}] with KSBT and KCp*; isomorphous crystals of [K(15-crown-5){sub 2}] [Ln(Cp*)(SBT){sub 3}].THF [Ln = La, Ce, Nd] were formed upon addition of 15-crown-5. Comparison of the crystal structures of the pentagonal bipyramidal complexes [M(Cp*)(SBT){sub 3}]{sup -} reveals that the M-Nax distances are shorter than the M-Neq distances, whatever the metal, the phenomenon being enhanced in the U(III) compound versus the Ln(III) analogues. The structural data obtained by relativistic density functional theory (DFT) calculations reproduce experimental trends. Electronic population and molecular orbital analyses show that the structural differences in the series of [M(Cp*)(SBT){sub 3}]{sup -} anions are related to the uranium 5f orbital-ligand mixing, which is greater than the lanthanide 4f orbital-ligand mixing. Moreover, the consideration of the corresponding bond orders and the analysis of the bonding energy bring to light a strong and specific interaction between the uranium and apical nitrogen atoms. (authors)

  19. Development of the Falea polymetallic uranium project

    International Nuclear Information System (INIS)

    Ring, R.; Freeman, P.

    2014-01-01

    The Falea uranium, silver, copper deposit is located in south western Mali, West Africa and is owned by Denison Mines Corp. The current resource estimate is approximately 45 million pounds of U_3O_8 [~17,300 t U] at an average grade of ~ 0.07% U_3O_8. [~0.06% U].The deposit also contains ~37 million Oz Ag and ~70,000 t Cu. The dominant uranium mineral is uraninite, copper is present mainly as chalcopyrite and silver mainly as argentite, and in its native form. Only 5% of the property has been explored to date, and all zones remain open. This paper reports the results of several stages of metallurgical investigations to support ongoing economic studies for the project. The polymetallic nature of the Falea deposit dictates that there are a range of flowsheet options. The ore contains both carbonate and sulphide mineralisations, which have potential impacts on acid and alkaline leaching, respectively. There is also the need to recover both silver and copper. Two primary flowsheet options were considered: 1) Acid leach of ore to recover uranium / flotation of leach residue to recover sulphide concentrate, treatment of concentrate for Cu and Ag recovery; 2) Flotation of ore / alkaline leaching of flotation tails to recover uranium and treatment of flotation concentrate for Cu and Ag recovery. A number of sub-options were considered for each flowsheet. Test work showed that high recoveries of copper and silver to flotation concentrate were obtained for both flotation of ore or acid leach residue. Uranium extraction was also > 90% for both acid and alkaline leaching. The preferred flowsheet was selected after trade-off studies by DRA. This paper presents an overview of the various flowsheet options considered, an outline of the preferred flowsheet, and the results and conclusions of on-going engineering and laboratory/pilot studies to refine the preferred flowsheet. (author)

  20. Uranium supply and demand

    Energy Technology Data Exchange (ETDEWEB)

    Spriggs, M J

    1976-01-01

    Papers were presented on the pattern of uranium production in South Africa; Australian uranium--will it ever become available; North American uranium resources, policies, prospects, and pricing; economic and political environment of the uranium mining industry; alternative sources of uranium supply; whither North American demand for uranium; and uranium demand and security of supply--a consumer's point of view. (LK)

  1. A Case of Argyria Following Colloidal Silver Ingestion

    OpenAIRE

    Kwon, Hyok Bu; Lee, Joon Ho; Lee, Seung Ho; Lee, Ai Young; Choi, Jong Sun; Ahn, Yeon Soon

    2009-01-01

    Argyria is a rare cutaneous discoloration caused by the intake of silver or various compounds containing silver. We report a case of argyria in a 73-year-old male following ingestion of colloidal silver as an alternative medicine over 5 years. He had a diffuse, slate gray discoloration of his face and hands. A biopsy specimen from the face revealed brown-black extracellular granules in the upper dermis and between collagen bundles. We also found silver particles in the mucous of the colon. Th...

  2. Uranium from seawater

    International Nuclear Information System (INIS)

    Gregg, D.; Folkendt, M.

    1982-01-01

    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 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 3 in seawater instead of the reported values of 10 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 5 in fresh water. However, the system was not tested in seawater

  3. Silver diamine fluoride: a caries "silver-fluoride bullet".

    Science.gov (United States)

    Rosenblatt, A; Stamford, T C M; Niederman, R

    2009-02-01

    The antimicrobial use of silver compounds pivots on the 100-year-old application of silver nitrate, silver foil, and silver sutures for the prevention and treatment of ocular, surgical, and dental infections. Ag(+) kills pathogenic organisms at concentrations of linings, water purification systems, hospital gowns, and caries prevention. To distill the current best evidence relative to caries, this systematic review asked: Will silver diamine fluoride (SDF) more effectively prevent caries than fluoride varnish? A five-database search, reference review, and hand search identified 99 human clinical trials in three languages published between 1966 and 2006. Dual review for controlled clinical trials with the patient as the unit of observation, and excluding cross-sectional, animal, in vitro studies, and opinions, identified 2 studies meeting the inclusion criteria. The trials indicated that SDF's lowest prevented fractions for caries arrest and caries prevention were 96.1% and 70.3%, respectively. In contrast, fluoride varnish's highest prevented fractions for caries arrest and caries prevention were 21.3% and 55.7%, respectively. Similarly, SDF's highest numbers needed to treat for caries arrest and caries prevention were 0.8 (95% CI=0.5-1.0) and 0.9 (95% CI=0.4-1.1), respectively. For fluoride varnish, the lowest numbers needed to treat for caries arrest and prevention were 3.7 (95% CI=3.4-3.9) and 1.1 (95% CI=0.7-1.4), respectively. Adverse events were monitored, with no significant differences between control and experimental groups. These promising results suggest that SDF is more effective than fluoride varnish, and may be a valuable caries-preventive intervention. As well, the availability of a safe, effective, efficient, and equitable caries-preventive agent appears to meet the criteria of both the WHO Millennium Goals and the US Institute of Medicine's criteria for 21st century medical care.

  4. US uranium reserves

    International Nuclear Information System (INIS)

    Hansen, M.V.

    1981-01-01

    The current low level of demand, compounded by rapidly rising costs and low prices, has caused a significant reduction in drilling for uranium in the United States, and the trend is likely to continue for a few more years. The effect on uranium reserves will be fewer additions to reserves because less exploration is being done. Further reductions will occur, especially in low-cost reserves, because of increasing costs, continuing depletion through production, and erosion through the high grading of deposits to fulfill previous contractual commitments. During the past several years, it has been necessary to increase the upper reserve cost level twice to compensate for rising costs. Rising costs are reducing the $15 reserves, the cost category corresponding most closely to the present market price, to an insignificant level. An encouraging factor related to US uranium reserves is that the US position internationally, as far as quantity is concerned, is not bad for the longer term. Also, there is a general opinion that US consumers would rather contract for domestic uranium than for foreign because of greater assurance of supply. Still another factor, nearly impossible to assess, is what effect rising costs in other countries will have on their uranium reserves. The annual conferences between the Grand Junction Area Office staff and major uranium companies provide a broad overview of the industry's perception of the future. It is not optimistic for the short term. Many companies are reducing their exploration and mining programs; some are switching to other more marketable mineral commodities, and a few are investing more heavily in foreign ventures. However, there is general optimism for the long term, and many predict a growth in demand in the mid-1980s. If the industry can survive the few lean years ahead, rising prices may restore its viability to former levels

  5. Tapping the unexploited plant resources for the synthesis of silver ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-03

    Sep 3, 2008 ... Electron Microscopy). ... tinct property of nanoparticles is that they exhibit larger ... including the plant source, the organic compounds in the ... The XRD Image of silver nanoparticles synthesised using Sunflower leaf extract.

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

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

  7. Uranium toxicology

    International Nuclear Information System (INIS)

    Ferreyra, Mariana D.; Suarez Mendez, Sebastian

    1997-01-01

    In this paper are presented the methods and procedures optimized by the Nuclear Regulatory Authority (ARN) for the determination of: natural uranium mass, activity of enriched uranium in samples of: urine, mucus, filters, filter heads, rinsing waters and Pu in urine, adopted and in some cases adapted, by the Environmental Monitoring and Internal Dosimetry Laboratory. The analyzed material corresponded to biological and environmental samples belonging to the staff professionally exposed that work in plants of the nuclear fuel cycle. For a better comprehension of the activities of this laboratory, it is included a brief description of the uranium radiochemical toxicity and the limits internationally fixed to preserve the workers health

  8. Silver carbonate and stability in colloidal silver: A by-product of the electric spark discharge method

    International Nuclear Information System (INIS)

    Tseng, Kuo-Hsiung; Liao, Chih-Yu; Tien, Der-Chi

    2010-01-01

    Many methods of producing colloidal silver (CS) include the introduction of surfactants to improve the suspensivity of the silver particles. The electric spark discharge method (ESDM) which involves pulses of direct current being passed through a silver electrode submerged in deionized water has been shown to successfully produce colloidal silver in a stable suspension without the use of chemical additives. A by-product of the electric spark discharge method, a silver ion compound (AgX), is shown to be the cause of the high suspensivity of the silver nanoparticles (AgNPs). The silver ion compound has been identified as Ag 2 CO 3 using X-ray diffraction, and it has been determined that the Ag 2 CO 3 is formed during the electric spark discharge process through a reaction with atmospheric CO 2 . It has been shown that an Ag 2 CO 3 concentration of 10 ppm or more is sufficient to generate a stable suspension of silver particles. Because of the occurrence of Ag 2 CO 3 , the electric spark discharge method can produce stable colloidal silver.

  9. In situ synthesis of silver benzene-dithiolate hybrid films

    Energy Technology Data Exchange (ETDEWEB)

    Brenier, Roger, E-mail: roger.brenier@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Piednoir, Agnès, E-mail: agnes.piednoir@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Bertorelle, Franck, E-mail: franck.bertorelle@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Penuelas, José, E-mail: jose.penuelas@ec-lyon.fr [Université de Lyon, Institut des Nanotechnologies de Lyon, Ecole Centrale de Lyon, CNRS, UMR 5270, 36 rue Guy de Collongues, F69134 Ecully (France); Grenet, Geneviève, E-mail: genevieve.grenet@ec-lyon.fr [Université de Lyon, Institut des Nanotechnologies de Lyon, Ecole Centrale de Lyon, CNRS, UMR 5270, 36 rue Guy de Collongues, F69134 Ecully (France)

    2016-02-01

    In this article, a method for in situ synthesis of silver benzene-dithiolate hybrid films is presented. Silver nanoparticles, generated on ZrO{sub 2} films, are transformed into silver benzene 1,4-dithiolate or, partially, into silver benzene 1,2-dithiolate after sample immersion in the corresponding thiol solutions. These transformations occur at room temperature owing to the catalytic action of ZrO{sub 2}. It is also shown that TiO{sub 2} in place of ZrO{sub 2} is very efficient, both for the catalytic generation of silver nanoparticles and for their further transformation in benzene 1,4-dithiolate compound. This latter semiconductor has an optical bandgap of about 3 eV and the film is made of touching nanoparticles in an amorphous state. Our work has potential applications in the electronic and photovoltaic fields. - Highlights: • A method for in situ synthesis of silver benzene-dithiolate hybrid semiconductor films is presented. • Silver nanoparticles are, first, generated on ZrO{sub 2} or on TiO{sub 2} coated silica substrates. • The samples are immersed in benzene dithiol solution for two days at room temperature. • During the immersion, the silver nanoparticles are transformed into silver benzene dithiolate. • The silver benzene dithiolate film is made of amorphous nanoparticles with a banbgap of 3 eV.

  10. Model of the coercion uranium hexafluoride on a human body

    International Nuclear Information System (INIS)

    Babenko, S.P.

    2007-01-01

    A method for calculating certain quantities characterizing the effect of uranium hexafluoride (UF 6 ) on the human body under industrial conditions in uranium enrichment plants is described. It is assumed that the effect is determined by uranium and fluorine inhaled together with the products of hydrolysis of uranium hexafluoride. The proposed complex model consists of three models, the first of which describes the contamination of the industrial environment and the second and third describe inhalation and percutaneous intake. A relation is obtained between uranium and fluorine intake and the uranium hexafluoride concentration in air at the moment the compound is discharged [ru

  11. International Uranium Resources Evaluation Project (IUREP) national favourability studies: Taiwan

    International Nuclear Information System (INIS)

    1977-12-01

    Taiwan is an island of 36,000 sq km located 160 km east of mainland China. Geologically, the oldest rocks are Tertiary, and the only igneous rocks on the island are Quaternary andesites and basalts. Copper, gold, and silver are the only known metallic minerals produced. Uranium occurrences and exploration efforts are unknown. The potential uranium resource of Taiwan is considered a category 1 resource. (author)

  12. Rossing uranium

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    In this article the geology of the deposits of the Rossing uranium mine in Namibia is discussed. The planning of the open-pit mining, the blasting, drilling, handling and the equipment used for these processes are described

  13. Uranium, depleted uranium, biological effects

    International Nuclear Information System (INIS)

    2001-01-01

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

  14. Estimation of uranium forms in oceanic water

    International Nuclear Information System (INIS)

    Krylov, O.T.; Novikov, P.D.; Nesterova, M.P.

    1985-01-01

    A critical consideration is given to the notions about uranium forms in ocean water. To estimate uranium forms a model is suggested which takes into account possjble formation of complexes of uranyl ions and ocean water anions Cl - , SO 4 2- , CO 3 2- , HCO 3 - , OH - , F - . The available published data are used to estimate necessary thermodynamic stability constants of the complexes, activity coefficients and concentration of componenets. The thermodynamic calculation shows that uranium hydroxocomplex compounds UO 2 (OH) 4 2- (99.17%) and UO 2 (OH) 3 - (083%) are the most probable uranium forms in ocear water of 34.3% salinity at 25 deg C and 1 atm pressure

  15. Uranium loans

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    When NUEXCO was organized in 1968, its founders conceived of a business based on uranium loans. The concept was relatively straightforward; those who found themselves with excess supplies of uranium would deposit those excesses in NUEXCO's open-quotes bank,close quotes and those who found themselves temporarily short of uranium could borrow from the bank. The borrower would pay interest based on the quantity of uranium borrowed and the duration of the loan, and the bank would collect the interest, deduct its service fee for arranging the loan, and pay the balance to those whose deposits were borrowed. In fact, the original plan was to call the firm Nuclear Bank Corporation, until it was discovered that using the word open-quotes Bankclose quotes in the name would subject the firm to various US banking regulations. Thus, Nuclear Bank Corporation became Nuclear Exchange Corporation, which was later shortened to NUEXCO. Neither the nuclear fuel market nor NUEXCO's business developed quite as its founders had anticipated. From almost the very beginning, the brokerage of uranium purchases and sales became a more significant activity for NUEXCO than arranging uranium loans. Nevertheless, loan transactions have played an important role in the international nuclear fuel market, requiring the development of special knowledge and commercial techniques

  16. Study of physical, chemical and electronic properties of binaries and ternaries uranium compounds in the U-Si-B and U-Pt-Si systems

    International Nuclear Information System (INIS)

    Brisset, Nicolas

    2016-01-01

    Two main research axes were defined for this Ph-D work: (i) studying the effect of light elements (B, C) on the stability of U-Si compounds, and (ii) identifying and physically characterizing new phases in the U-Pt-Si system. Minor additions of carbon and boron in U-Si samples revealed that the formation of U 5 Si 4 would be correlated to the presence of these light elements, questioning its existence in the U-Si system. To evaluate the boron potential as a stimulant for non-metallic light elements of the second period (C, N, O), the isothermal section of the ternary phase diagram U-Si-B has been drawn at 927 C, disclosing solid equilibrium mainly between the UB and U-Si binary axes and the existence of the novel compound U 20 Si 16 B 3 , isostructural to the carbon equivalent one. These results suggest a specific behavior for a given light element on the U-Si phase relations. The isothermal section at 900 C of the U-Pt-Si ternary system was experimentally determined, leading to the discovery of 14 new phases, among which U 3 Pt 4 Si 6 , U 3 Pt 6 Si 4 and U 3 Pt 7 Si crystallized in their own structural type. As a prerequisite for this study, the phase relations in the U-Pt binary phase diagram were re-examined for the composition range 30 at.% and 70 at.% Pt, leading to a new assessment of the phase diagram which comprises the new U 3 Pt 4 compound. The temperature of the transformations has been measured by DTA. By coupling our experimental results to the literature data, a modeling of the phase diagram by the Calphad method was performed. Physical characterizations of the new U 3 Pt 4 compound revealed a moderate heavy fermion behavior, with ferromagnetic ordering below Tc = 7(1) K. As a side project, a study of the U 3 TGe 5 family with the anti-Hf 5 CuSn 3 structural type lead to the discovery of nine new compounds for T = V, Cr, Mn, Zr, Nb, Mo, Hf, Ta and W in addition to the previously reported U 3 TiGe 5 . Their magnetic and electronic properties were

  17. Optimization of silver-dielectric-silver nanoshell for sensing applications

    International Nuclear Information System (INIS)

    Shirzaditabar, Farzad; Saliminasab, Maryam

    2013-01-01

    In this paper, resonance light scattering (RLS) properties of a silver-dielectric-silver nanoshell, based on quasi-static approach and plasmon hybridization theory, are investigated. Scattering spectrum of silver-dielectric-silver nanoshell has two intense and clearly separated RLS peaks and provides a potential for biosensing based on surface plasmon resonance and surface-enhanced Raman scattering. The two RLS peaks in silver-dielectric-silver nanoshell are optimized by tuning the geometrical dimensions. In addition, the optimal geometry is discussed to obtain the high sensitivity of silver-dielectric-silver nanoshell. As the silver core radius increases, the sensitivity of silver-dielectric-silver nanoshell decreases whereas increasing the middle dielectric thickness increases the sensitivity of silver-dielectric-silver nanoshell

  18. Determination of inorganic compounds in drinking water on the basis of house water heater scale, part 1: Determination of heavy metals and uranium

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2004-01-01

    Full Text Available The analysis of scale originated from drinking water on the house water heater, showed that scale is basically calcium carbonate that crystallizes hexagonally in the form of calcite. Scale taken as a sample from different spots in Belgrade – upper town of Zemun (sample 1 and Pančevo (sample 2 showed different configuration although it came from the same waterworks. That indicates either that the water flowing through waterworks pipes in different parts of the city is not the same or the waterworks net is not the same (age, maintaining, etc. All the elements which are dominant in drinking water (Ca, Mg, K, and Na, and which could be found in water by natural processes, are by their content far below the values regulated by law. The analysis also showed the presence of many metals: Ti, Pb, Zn, Cu Li, Sr, Cd, and Cr in the first sample, which are not found in the scale taken near Pančevo. The results obtained by calculating the mass concentration in drinking water on the basis of scale content, showed that both waters belonged to the category of low mineral waters. Contents of inorganic substances in these waters (117.85 mg/dm3 for sample 1 or 80.83 mg/dm3 for sample 2 are twice lower than the values predicted by the legislation. Gammaspectrometric analysis indicates the presence of radioactive elements – uranium and strontium which can influence human health.

  19. Uranium extraction from gold-uranium ores

    Energy Technology Data Exchange (ETDEWEB)

    Laskorin, B.N.; Golynko, Z.Sh.

    1981-01-01

    The process of uranium extraction from gold-uranium ores in the South Africa is considered. Flowsheets of reprocessing gold-uranium conglomerates, pile processing and uranium extraction from the ores are presented. Continuous counter flow ion-exchange process of uranium extraction using strong-active or weak-active resins is noted to be the most perspective and economical one. The ion-exchange uranium separation with the succeeding extraction is also the perspective one.

  20. Spectroscopy and chemistry of uranium IV

    International Nuclear Information System (INIS)

    Folcher, G.; Rigny, P.

    1980-06-01

    Different fundamental research papers on uranium IV are presented, some were never edited. Molecular spectroscopy was used for identification and structural study of uranium IV in aqueous or organic solutions. The fields studied are: coordination, stereochemistry, electronic structure and chemical properties. For interpretation of results some studies were made with solid compounds or with thorium compounds or thorium complexes. Knowledge of actinides chemistry is improved, uranium and thorium being models for 5 f ions, extractive chemistry is better understood and new applications are possible [fr

  1. Sponge-like silver obtained by decomposition of silver nitrate hexamethylenetetramine complex

    International Nuclear Information System (INIS)

    Afanasiev, Pavel

    2016-01-01

    Silver nitrate hexamethylenetetramine [Ag(NO 3 )·N 4 (CH 2 ) 6 ] coordination compound has been prepared via aqueous route and characterized by chemical analysis, XRD and electron microscopy. Decomposition of [Ag(NO 3 )·N 4 (CH 2 ) 6 ] under hydrogen and under inert has been studied by thermal analysis and mass spectrometry. Thermal decomposition of [Ag(NO 3 )·N 4 (CH 2 ) 6 ] proceeds in the range 200–250 °C as a self-propagating rapid redox process accompanied with the release of multiple gases. The decomposition leads to formation of sponge-like silver having hierarchical open pore system with pore size spanning from 10 µm to 10 nm. The as-obtained silver sponges exhibited favorable activity toward H 2 O 2 electrochemical reduction, making them potentially interesting as non-enzyme hydrogen peroxide sensors. - Graphical abstract: Thermal decomposition of silver nitrate hexamethylenetetramine coordination compound [Ag(NO 3 )·N 4 (CH 2 ) 6 ] leads to sponge like silver that possesses open porous structure and demonstrates interesting properties as an electrochemical hydrogen peroxide sensor. Display Omitted - Highlights: • [Ag(NO 3 )·N 4 (CH 2 ) 6 ] orthorhombic phase prepared and characterized. • Decomposition of [Ag(NO 3 )·N 4 (CH 2 ) 6 ] leads to metallic silver sponge with opened porosity. • Ag sponge showed promising properties as a material for hydrogen peroxide sensors.

  2. Uranium mining

    International Nuclear Information System (INIS)

    2008-01-01

    Full text: The economic and environmental sustainability of uranium mining has been analysed by Monash University researcher Dr Gavin Mudd in a paper that challenges the perception that uranium mining is an 'infinite quality source' that provides solutions to the world's demand for energy. Dr Mudd says information on the uranium industry touted by politicians and mining companies is not necessarily inaccurate, but it does not tell the whole story, being often just an average snapshot of the costs of uranium mining today without reflecting the escalating costs associated with the process in years to come. 'From a sustainability perspective, it is critical to evaluate accurately the true lifecycle costs of all forms of electricity production, especially with respect to greenhouse emissions, ' he says. 'For nuclear power, a significant proportion of greenhouse emissions are derived from the fuel supply, including uranium mining, milling, enrichment and fuel manufacture.' Dr Mudd found that financial and environmental costs escalate dramatically as the uranium ore is used. The deeper the mining process required to extract the ore, the higher the cost for mining companies, the greater the impact on the environment and the more resources needed to obtain the product. I t is clear that there is a strong sensitivity of energy and water consumption and greenhouse emissions to ore grade, and that ore grades are likely to continue to decline gradually in the medium to long term. These issues are critical to the current debate over nuclear power and greenhouse emissions, especially with respect to ascribing sustainability to such activities as uranium mining and milling. For example, mining at Roxby Downs is responsible for the emission of over one million tonnes of greenhouse gases per year and this could increase to four million tonnes if the mine is expanded.'

  3. Internal dosimetry and radiotoxicity of long-lived uranium isotopes

    International Nuclear Information System (INIS)

    Jacobi, W.

    1980-03-01

    The dose to relevant tissues and the effective dose equivalent by ingestion and inhalation of uranium compounds are evaluated on the basis of the new metabolic and dosimetric models recommended by ICRP. Applying these dose factors annual limits for intake of these compounds by workers are derived. Finally the natural uranium exposure of the population is described. From the measured natural U-content of body tissues dose factors for the dietary intake of uranium can be estimated. (orig.) [de

  4. Uranium enrichment

    International Nuclear Information System (INIS)

    Rae, H.K.; Melvin, J.G.

    1988-06-01

    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

  5. Biological synthesis of very small silver nanoparticles by culture supernatant of Klebsiella pneumonia: The effects of visible-light irradiation and the liquid mixing process

    International Nuclear Information System (INIS)

    Mokhtari, Narges; Daneshpajouh, Shahram; Seyedbagheri, Seyedali; Atashdehghan, Reza; Abdi, Khosro; Sarkar, Saeed; Minaian, Sara; Shahverdi, Hamid Reza; Shahverdi, Ahmad Reza

    2009-01-01

    This study has investigated different visible-light irradiation's effect on the formation of silver nanoparticles from silver nitrate using the culture supernatant of Klebsiella pneumonia. Our study shows that visible-light emission can significantly prompt the synthesis of silver nanoparticles. Also, the study experimentally investigated the liquid mixing process effect on silver nanoparticle synthesis by visible-light irradiation. This study successfully synthesized uniformly dispersed silver nanoparticles with a uniform size and shape in the range of 1-6 nm with an average size of 3 nm. Furthermore, the study investigated the mechanism of the reduction of silver ions by culture supernatant of K. pneumonia, and used X-ray diffraction to characterize silver chloride as an intermediate compound. Silver chloride was prepared synthetically and used as a substrate for the synthesis of silver nanoparticles by culture supernatant of K. pneumonia. The silver nanoparticles have been prepared from silver chloride during this investigation for the first time.

  6. Biological synthesis of very small silver nanoparticles by culture supernatant of Klebsiella pneumonia: The effects of visible-light irradiation and the liquid mixing process

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari, Narges [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Daneshpajouh, Shahram; Seyedbagheri, Seyedali; Atashdehghan, Reza [Hydrometallurgy Research Unit, Research and Development Center, National Iranian Copper Industries Company, Sarcheshmeh, Rafsanjan (Iran, Islamic Republic of); Abdi, Khosro [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sarkar, Saeed [Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Minaian, Sara [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shahverdi, Hamid Reza [Department of Material Science, Faculty of Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Shahverdi, Ahmad Reza, E-mail: shahverd@sina.tums.ac.ir [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2009-06-03

    This study has investigated different visible-light irradiation's effect on the formation of silver nanoparticles from silver nitrate using the culture supernatant of Klebsiella pneumonia. Our study shows that visible-light emission can significantly prompt the synthesis of silver nanoparticles. Also, the study experimentally investigated the liquid mixing process effect on silver nanoparticle synthesis by visible-light irradiation. This study successfully synthesized uniformly dispersed silver nanoparticles with a uniform size and shape in the range of 1-6 nm with an average size of 3 nm. Furthermore, the study investigated the mechanism of the reduction of silver ions by culture supernatant of K. pneumonia, and used X-ray diffraction to characterize silver chloride as an intermediate compound. Silver chloride was prepared synthetically and used as a substrate for the synthesis of silver nanoparticles by culture supernatant of K. pneumonia. The silver nanoparticles have been prepared from silver chloride during this investigation for the first time.

  7. Uranium update

    International Nuclear Information System (INIS)

    Steane, R.

    1997-01-01

    This paper is about the current uranium mining situation, especially that in Saskatchewan. Canada has a unique advantage with the Saskatchewan uranium deposits. Making the most of this opportunity is important to Canada. The following is reviewed: project development and the time and capital it takes to bring a new project into production; the supply and demand situation to show where the future production fits into the world market; and our foreign competition and how we have to be careful not to lose our opportunity. (author)

  8. Uranium determination in different compositions

    International Nuclear Information System (INIS)

    Bulyanitsa, L.S.; Ivanova, K.S.; Ryzhinskij, M.V.; Alekseeva, N.A.; Solntseva, L.F.; Shereshevskaya, I.I.

    1978-01-01

    For clarifying the suitability of two different methods of analysis for determining uranium without its previous purification, the analysis of uranium carbides (UC, UC 2 , UC - ZrC) and alloys (U - Al, U - Zr - Nb, U- Ti) has been carried out. Dissolution of the compositions examined was carried out either after previous calcining (UC, UC 2 ) or fusion with KHSO 4 (UC - ZrC), or in phosphoric acid (alloys). The first method, a variant of potentiometric titration, has been modified for small amounts of uranium. Titration was carried out on a semiautomatic titrating unit. The uranium amount per titration is about 4 to 5 mg. The second method of analysis is the coulombmetric titration at a constant current intensity. The quantity of uranium per titration was equal to 1 - 3 mg. The statistical processing of the results obtained was carried out by a dispersion analysis that allowed to reveal the influence of separate factors, such as method of analysis, type of composition, the non-uniformity of a sample, the enumerated factors influencing the dispersion of the analysis results. It has been shown that the both methods are equally suitable for analysis of the uranium compounds examined

  9. Machining of uranium and uranium alloys

    International Nuclear Information System (INIS)

    Morris, T.O.

    1981-01-01

    Uranium and uranium alloys can be readily machined by conventional methods in the standard machine shop when proper safety and operating techniques are used. Material properties that affect machining processes and recommended machining parameters are discussed. Safety procedures and precautions necessary in machining uranium and uranium alloys are also covered. 30 figures

  10. Exploring the thermoelectric and magnetic properties of uranium selenides: Tl2Ag2USe4 and Tl3Cu4USe6

    International Nuclear Information System (INIS)

    Azam, Sikander; Khan, Saleem Ayaz; Din, Haleem Ud; Khenata, Rabah; Goumri-Said, Souraya

    2016-01-01

    The electronic, magnetic and thermoelectric properties of Tl 2 Ag 2 USe 4 and Tl 3 Cu 4 USe 6 compounds were investigated using the full potential linear augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). The exchange correlation was treated with the generalized gradient approximation plus optimized effective Hubbard parameter and spin–orbit coupling (GGA+U+SOC). The present uranium selenides show narrow direct energy band gap values of 0.7 and 0.875 eV for Tl 2 Ag 2 USe 4 and Tl 3 Cu 4 USe 6 respectively. For both selenides U-d/f states are responsible for electrical transport properties. Uranium atoms were the most contributors in the magnetic moment compared to other atoms and show ferromagnetic nature. The spin density isosurfaces show the polarization of neighboring atoms of Uranium, such as silver/copper and selenium. Thermoelectric calculations reveal that Tl 3 Cu 4 USe 6 is more suitable for thermoelectric device applications than Tl 2 Ag 2 USe 4 . - Highlights: • Electronic, magnetic and thermoelectric properties of uranium selenides are investigated with DFT. • They show a narrow direct energy band gap of 0.7 and 0.875 eV. • U-d/f states are responsible for electrical transport properties. • Tl 3 Cu 4 USe 6 is more suitable for thermoelectric device applications than Tl 2 Ag 2 USe 4 .

  11. New complexes of silver (I) with N-hydroxy-succinimide

    Science.gov (United States)

    Sibiescu, Doina; Mîţǎ, Carmen; Vizitiu, Mihaela; Crudu, Andra Manuela

    2016-12-01

    Over the last period of time silver was considerably studied due to its lower resistivity. In the field of materials science, silver was used in applications such as: microelectronics components of high - temperature superconductiviting materials, bactericidal coatings and others domains. This study presents the process of obtaining and characterization the new complexes of silver (I) with Nhydroxy- succinimide. In the process of obtaining the new complex compounds in aqous solution, first we have to look at conductometry and UV-Vis absorbtion spectroscopy in order to determine the molar ratio silver : N-hydroxysuccinimide and the stability constants. The obtained solid coordination compounds were characterized by elemental analysis, IR spectroscopy and also was investigated of their thermostability. The X-ray powder diffraction reflects that the complexes compounds of silver (I) with N-hydroxysuccinimide are amorphous. In our further studies we want to determine if the new synthetized compounds will present the same or improuved properties as in the above mentioned silver characteristics.

  12. Uranium mining

    International Nuclear Information System (INIS)

    Cheeseman, E.W.

    1980-01-01

    The international uranium market appears to be currently over-supplied with a resultant softening in prices. Buyers on the international market are unhappy about some of the restrictions placed on sales by the government, and Canadian sales may suffer as a result. About 64 percent of Canada's shipments come from five operating Ontario mines, with the balance from Saskatchewan. Several other properties will be producing within the next few years. In spite of the adverse effects of the Three Mile Island incident and the default by the T.V.A. of their contract, some 3 600 tonnes of new uranium sales were completed during the year. The price for uranium had stabilized at US $42 - $44 by mid 1979, but by early 1980 had softened somewhat. The year 1979 saw the completion of major environmental hearings in Ontario and Newfoundland and the start of the B.C. inquiry. Two more hearings are scheduled for Saskatchewan in 1980. The Elliot Lake uranium mining expansion hearings are reviewed, as are other recent hearings. In the production of uranium for nuclear fuel cycle, environmental matters are of major concern to the industry, the public and to governments. Research is being conducted to determine the most effective method for removing radium from tailings area effluents. Very stringent criteria are being drawn up by the regulatory agencies that must be met by the industry in order to obtain an operating licence from the AECB. These criteria cover seepages from the tailings basin and through the tailings retention dam, seismic stability, and both short and long term management of the tailings waste management area. (auth)

  13. 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.

  14. Uranium industry annual 1996

    International Nuclear Information System (INIS)

    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

  15. Uranium industry annual, 1991

    International Nuclear Information System (INIS)

    1992-10-01

    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

  16. Uranium and thorium migration under dislocative metamorphism

    International Nuclear Information System (INIS)

    Titov, V.K.; Bilibina, T.V.; Dashkova, A.D.; Il'in, V.K.; Makarova, L.I.; Shmuraeva, L.Ya.

    1978-01-01

    Investigated were peculiarities of uranium and thorium behaviour in the process of dislocation metamorphism on the basis of regional fracture zones of early-proterozoic embedding of Ukrainian, Aldan and Baltic shields. The studied zones correspond to tectonite of green-shale and almandin-amphibolite facies of regional metamorphism according to mineral associations. The most peculiar feature of the tectonites of green-shale facies is uranium presence in migrationally able forms, which can be involved afterwards into the ore process by hydrothermal solutions. Adsorved forms of uranium on the crystal surface or separate grains and in the cracks, as well as microinclusions of uranium minerals, selectively timed to mineral structure defects prevail among easily mobile uranium compounds. Dissolved uranium is present, evidently in gas-liquid inclusions in minerals and pore waters. There forms of uranium presence are peculiar for epidote-chlorite mylonites, as well as cataclasites and diaphthorites related to them by blastomylonites of almandin-amphibolite facies. Wide range of manifestation of this process, caused by multikilometer extension of deep fracture zones permit to consider the formations of green-shale facies of dislocation metamorphism as one of the main uranium sources in deposit formation in different uranium-ore associations different age

  17. Production and analysis of ultradispersed uranium oxide powders

    Science.gov (United States)

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

    2010-05-01

    Spectroscopic studies are made of the laser plasma formed near the surface of a porous body containing nanoquantities of uranium compounds which is irradiated by two successive laser pulses. The feasibility of using laser chemical methods for obtaining nanoclusters of uranium oxide particles in the volume of a porous body and the simultaneous possibility of determining the uranium content with good sensitivity are demonstrated. The thermochemical and spectral characteristics of the analogs of their compounds with chlorine are determined and studied. The possibility of producing uranium dioxides under ordinary conditions and their analysis in the reaction products is demonstrated.

  18. Behaviour of uranium under irradiation

    International Nuclear Information System (INIS)

    Adda, Y.; Mustelier, J.P.; Quere, Y.; Commissariat a l'Energie Atomique, Fontenay-aux-Roses

    1964-01-01

    The main results obtained in a study of the formation of defects caused in uranium by fission at low temperature are reported. By irradiation at 20 K. it was possible to determine the number of Frenkel pairs produced by one fission. An analysis of the curves giving the variations in electrical resistivity shows the size of the displacement spikes and the mechanism of defect creation due to fission. Irradiations at 77 K gave additional information, showing behaviour differences in the case of recrystallised and of cold worked uranium. The diffusion of rare gases was studied using metal-rare gas alloys obtained by electrical discharge, and samples of irradiated uranium. Simple diffusion is only responsible for the release of the rare gases under vacuum in cases where the rare gas content is very low (very slightly irradiated U). On the other hand when the concentration is higher (samples prepared by electrical discharge) the gas is given off by the formation, growth and coalescence of bubbles; the apparent diffusion coefficient is then quite different from the true coefficient and cannot be used in calculations on swelling. The various factors governing the phenomenon of simple diffusion were examined. It was shown in particular that a small addition of molybdenum could reduce the diffusion coefficient by a factor of 100. The precipitation of gas in uranium (Kr), in silver (Kr) and in Al-Li alloy (He) have been followed by measurement of the crystal parameter and of the electrical resistivity, and by electron microscope examination of thin films. The important part played by dislocations in the generation and growth of bubbles has been demonstrated, and it has been shown also that precipitation of bubbles on the dislocation lattice could block the development of recrystallisation. The results of these studies were compared with observations made on the swelling of uranium and uranium alloys U Mo and U Nb strongly irradiated between 400 and 700 C. In the case of Cubic

  19. Amine synergism in uranium extraction

    International Nuclear Information System (INIS)

    Rinelli, G.; Abbruzzese, C.

    1977-01-01

    Commercial products based on C 8 to C 12 tertiary amine mixtures are now widely used in the solvent extraction of uranium from sulphuric pregnant solutions. The satisfactory results generally obtained have never required an analysis of the synergistic effects of amine combinations similar to that carried out for the organo-phosphorus compounds. In the research described the increase in the extraction power of an organic phase composed of an amine binary mixture was studied with regard to an aqueous solution from the sulphuric acid treatment of uranium ore. On the basis of the experimental results obtained, it is possible to select the best composition of the amine mixture to ensure a percentage increase in uranium recovery. Bearing in mind the tendency for the yellow-cake price to rise, the study is considered to be a useful contribution in the context of commercial products currently available on the market. (author)

  20. Solubility of airborne uranium samples from uranium processing plant

    International Nuclear Information System (INIS)

    Kravchik, T.; Oved, S.; Sarah, R.; Gonen, R.; Paz-Tal, O.; Pelled, O.; German, U.; Tshuva, A.

    2005-01-01

    Full text: During the production and machining processes of uranium metal, aerosols might be released to the air. Inhalation of these aerosols is the main route of internal exposure of workers. To assess the radiation dose from the intake of these uranium compounds it is necessary to know their absorption type, based on their dissolution rate in extracellular aqueous environment of lung fluid. The International Commission on Radiological Protection (ICRP) has assigned UF4 and U03 to absorption type M (blood absorption which contains a 10 % fraction with an absorption rate of 10 minutes and 90 % fraction with an absorption rate of 140 fays) and UO2 and U3O8 to absorption type S (blood absorption rate with a half-time of 7000 days) in the ICRP-66 model.The solubility classification of uranium compounds defined by the ICRP can serve as a general guidance. At specific workplaces, differences can be encountered, because of differences in compounds production process and the presence of additional compounds, with different solubility characteristics. According to ICRP recommendations, material-specific rates of absorption should be preferred to default parameters whenever specific experimental data exists. Solubility profiles of uranium aerosols were determined by performing in vitro chemical solubility tests on air samples taken from uranium production and machining facilities. The dissolution rate was determined over 100 days in a simultant solution of the extracellular airway lining fluid. The filter sample was immersed in a test vial holding 60 ml of simultant fluid, which was maintained at a 37 o C inside a thermostatic bath and at a physiological pH of 7.2-7.6. The test vials with the solution were shaken to simulate the conditions inside the extracellular aqueous environment of the lung as much as possible. The tests indicated that the uranium aerosols samples taken from the metal production and machining facilities at the Nuclear Research Center Negev (NRCN

  1. Uranium - what role

    International Nuclear Information System (INIS)

    Grey, T.; Gaul, J.; Crooks, P.; Robotham, R.

    1980-01-01

    Opposing viewpoints on the future role of uranium are presented. Topics covered include the Australian Government's uranium policy, the status of nuclear power around the world, Australia's role as a uranium exporter and problems facing the nuclear industry

  2. Brazilian uranium exploration program

    International Nuclear Information System (INIS)

    Marques, J.P.M.

    1981-01-01

    General information on Brazilian Uranium Exploration Program, are presented. The mineralization processes of uranium depoits are described and the economic power of Brazil uranium reserves is evaluated. (M.C.K.) [pt

  3. Uranium enrichment

    International Nuclear Information System (INIS)

    1991-11-01

    This paper analyzes under four different scenarios the adequacy of a $500 million annual deposit into a fund to pay for the cost of cleaning up the Department of Energy's (DOE) three aging uranium enrichment plants. These plants are located in Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. In summary the following was found: A fixed annual $500 million deposit made into a cleanup fund would not be adequate to cover total expected cleanup costs, nor would it be adequate to cover expected decontamination and decommissioning (D and D) costs. A $500 million annual deposit indexed to an inflation rate would likely be adequate to pay for all expected cleanup costs, including D and D costs, remedial action, and depleted uranium costs

  4. Uranium production

    International Nuclear Information System (INIS)

    Spriggs, M.

    1980-01-01

    The balance between uranium supply and demand is examined. Should new resources become necessary, some unconventional sources which could be considered include low-grade extensions to conventional deposits, certain types of intrusive rock, tuffs, and lake and sea-bed sediments. In addition there are large but very low grade deposits in carbonaceous shales, granites, and seawater. The possibility of recovery is discussed. Programmes of research into the feasibility of extraction of uranium from seawater, as a by-product from phosphoric acid production, and from copper leach solutions, are briefly discussed. Other possible sources are coal, old mine dumps and tailings, the latter being successfully exploited commercially in South Africa. The greatest constraints on increased development of U from lower grade sources are economics and environmental impact. It is concluded that apart from U as a by-product from phosphate, other sources are unlikely to contribute much to world requirements in the foreseeable future. (U.K.)

  5. Uranium enrichment

    International Nuclear Information System (INIS)

    1991-08-01

    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

  6. Derived enriched uranium market

    International Nuclear Information System (INIS)

    Rutkowski, E.

    1996-01-01

    The potential impact on the uranium market of highly enriched uranium from nuclear weapons dismantling in the Russian Federation and the USA is analyzed. Uranium supply, conversion, and enrichment factors are outlined for each country; inventories are also listed. The enrichment component and conversion components are expected to cause little disruption to uranium markets. The uranium component of Russian derived enriched uranium hexafluoride is unresolved; US legislation places constraints on its introduction into the US market

  7. Uranium. Suppl. Vol. C7

    International Nuclear Information System (INIS)

    Keim, R.; Keller, C.

    1982-01-01

    In this supplement volume C7 the nitrogen compounds of uranium-anides, imides, nitrides, nitrites, nitrates are dealt with. Whereas amides, imides and nitrates have only been of scientific interest up to now, uranium nitride and uranylnitrate are of great technological importance. Therefore the description of the chemical and physical characteristics of UN as a potential fuel for future reactors already comprises about 1/4 of this volume. Also the description of uranyl nitrate - as one of the most important commercial forms of uranium and because of its importance in the chemistry of nuclear fuel element reprocessing - comprises many pages. This is supplemented by further uranium nitrides, ternary and polynary nitrides, oxide nitrides, double nitrides of the various valence steps as well as nitrate complexes and ternary and quarternary systems containing uranyl nitrate. The radiation behaviour of UN, and its distribution (liquid/liquid, liquid solid) as well as the complex formation of the uranyl ion with nitrate are described in other volumes of the uranium series. (RB) [de

  8. Uranium industry annual, 1986

    International Nuclear Information System (INIS)

    1987-01-01

    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

  9. Uranium Industry. Annual 1984

    International Nuclear Information System (INIS)

    Lawrence, M.S.S.

    1985-01-01

    This report provides a statistical description of activities of the US uranium industry during 1984 and includes a statistical profile of the status of the industry at the end of 1984. It is based on the results of an Energy Information Administration (EIA) survey entitled ''Uranium Industry Annual Survey'' (Form EIA-858). The principal findings of the survey are summarized under two headings - Uranium Raw Materials Activities and Uranium Marketing Activities. The first heading covers exploration and development, uranium resources, mine and mill production, and employment. The second heading covers uranium deliveries and delivery commitments, uranium prices, foreign trade in uranium, inventories, and other marketing activities. 32 figs., 48 tabs

  10. Bioremediation of uranium contaminated Fernald soils

    International Nuclear Information System (INIS)

    Delwiche, M.E.; Wey, J.E.; Torma, A.E.

    1994-01-01

    This study investigated the use of microbial bioleaching for removal of uranium from contaminated soils. The ability of bacteria to assist in oxidation and solubilization of uranium was compared to the ability of fungi to produce complexing compounds which have the same effect. Biosorption of uranium by fungi was also measured. Soil samples were examined for changes in mineralogical properties due to these processes. On the basis of these laboratory scale studies a generalized flow sheet is proposed for bioremediation of contaminated Fernald soils

  11. Compared biokinetic and biological studies of chronic and acute inhalations of uranium compounds in the rat; Etudes biocinetique et biologique comparees d'inhalations chroniques et aigues de composes uraniferes chez le rat

    Energy Technology Data Exchange (ETDEWEB)

    Monleau, M

    2005-12-15

    Uranium is a natural, radioactive heavy metal, widely used in the nuclear industry in various chemical and isotopic forms. Its use in the fuel cycle involves the risk of radiological exposure for the workers, mainly via the inhalation of uranium particles. According to the workplace configuration, uranium contaminations can be acute or repeated, involve various chemical forms and different levels of enrichment, as well as involving one or several components. The dosimetric concepts and models available for workers' radiological protection, as well as most of the studies of the biological effects, correspond to acute exposure situations. Moreover the processes leading to pathological effects are little known in vivo. In this context, the main question is to know whether exposures due to repeated inhalation by rats induce the element kinetics and toxicity, which may be different from those observed after an acute exposure. In this study, comparison of the experimental and theoretical biokinetics of an insoluble uranium repeatedly inhaled over three weeks shows that a chronic contamination is correctly modelled, except for bone retention, by the sum of acute, successive and independent incorporations. Moreover, the kinetics of a soluble uranium inhaled irregularly can be modified by previous repeated exposure to an insoluble uranium. In certain cases therefore, exposure to uranium could modify its biokinetics during later exposures. At a toxicological level, the study demonstrates that the uranium particles inhaled repeatedly induce behavioural disruptions and genotoxic effects resulting in various sorts of DNA damage, in several cell types and certainly depending on the quantity inhaled. Exposures involving several uraniferous components produce a synergy effect. Moreover, repeated inhalations worsen the genotoxic effects in comparison to an acute exposure. This work demonstrates the importance of not ignoring the effects of the repetition of uranium exposure. It

  12. Compared biokinetic and biological studies of chronic and acute inhalations of uranium compounds in the rat; Etudes biocinetique et biologique comparees d'inhalations chroniques et aigues de composes uraniferes chez le rat

    Energy Technology Data Exchange (ETDEWEB)

    Monleau, M

    2005-12-15

    Uranium is a natural, radioactive heavy metal, widely used in the nuclear industry in various chemical and isotopic forms. Its use in the fuel cycle involves the risk of radiological exposure for the workers, mainly via the inhalation of uranium particles. According to the workplace configuration, uranium contaminations can be acute or repeated, involve various chemical forms and different levels of enrichment, as well as involving one or several components. The dosimetric concepts and models available for workers' radiological protection, as well as most of the studies of the biological effects, correspond to acute exposure situations. Moreover the processes leading to pathological effects are little known in vivo. In this context, the main question is to know whether exposures due to repeated inhalation by rats induce the element kinetics and toxicity, which may be different from those observed after an acute exposure. In this study, comparison of the experimental and theoretical biokinetics of an insoluble uranium repeatedly inhaled over three weeks shows that a chronic contamination is correctly modelled, except for bone retention, by the sum of acute, successive and independent incorporations. Moreover, the kinetics of a soluble uranium inhaled irregularly can be modified by previous repeated exposure to an insoluble uranium. In certain cases therefore, exposure to uranium could modify its biokinetics during later exposures. At a toxicological level, the study demonstrates that the uranium particles inhaled repeatedly induce behavioural disruptions and genotoxic effects resulting in various sorts of DNA damage, in several cell types and certainly depending on the quantity inhaled. Exposures involving several uraniferous components produce a synergy effect. Moreover, repeated inhalations worsen the genotoxic effects in comparison to an acute exposure. This work demonstrates the importance of not ignoring the effects of the repetition of uranium exposure

  13. Some peculiarities of the relationship between uranium and phosphate of nodular phosphorites of the Russian Platform

    Energy Technology Data Exchange (ETDEWEB)

    Kozlov, A A [Vsesoyuznyj Nauchno-Issledovatel' skij Inst. Yadernoj Geofiziki i Geokhimii, Moscow (USSR)

    1976-02-01

    In nodular phosphorites of the Cenomanian stage of the central regions of the Russian platform the uranium content of phosphate ranges within 20 to 50x10/sup -4/%. The maximum concentrations of uranium are found in amorphous phosphates, the richest in humic colloid. Uranium found in the bone phosphate of fossil reptiles is uniformly distributed throughout the bone tissue area, its content amounting to 30 to 40x10/sup -4/%. As bone phosphate reaches its holocrystalline modification, the uranium compounds are substituted and the uranium concentration decreases to 0.2x10/sup -4/%, i.e. it becomes 200 times lower. The most intensive sorption of uranium by phosphate occurs under the reducing conditions of diagenesis which is characterized by the most comprehensive combination of uranium-sorption factors: the existence of various uranium compounds in solution, isomorphic substitutions of all kinds, adsorption of uranium compounds and organic matter on the surfaces of submicron crystalline phosphate compounds. A decrease in the intensity of sorption factors leads to a decrease in the uranium content of phosphate. Under the oxidative conditions prevailed during the formation of Khoperian silicophosphorites, uranium has been sorbed by the phosphate only in negligible amounts (0.1x10/sup -4/%) due to the lack of organic colloids and uranium compounds capable of isomorphic substitution.

  14. Uranium price reporting systems

    International Nuclear Information System (INIS)

    1987-09-01

    This report describes the systems for uranium price reporting currently available to the uranium industry. The report restricts itself to prices for U 3 O 8 natural uranium concentrates. Most purchases of natural uranium by utilities, and sales by producers, are conducted in this form. The bulk of uranium in electricity generation is enriched before use, and is converted to uranium hexafluoride, UF 6 , prior to enrichment. Some uranium is traded as UF 6 or as enriched uranium, particularly in the 'secondary' market. Prices for UF 6 and enriched uranium are not considered directly in this report. However, where transactions in UF 6 influence the reported price of U 3 O 8 this influence is taken into account. Unless otherwise indicated, the terms uranium and natural uranium used here refer exclusively to U 3 O 8 . (author)

  15. Uranium Industry Annual, 1992

    International Nuclear Information System (INIS)

    1993-01-01

    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

  16. 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.

  17. Study of uranium(4) phosphites

    International Nuclear Information System (INIS)

    Avduevskaya, K.A.; Rozanov, I.A.; Mironova, V.S.

    1977-01-01

    Neutral and monosubstituted uranium phosphites U(HPO 3 ) 2 x2H 2 O and U(H 2 PO 3 ) 4 x2H 2 O and pyrophosphite U(H 2 P 2 O 5 ) 2 have been separated and identified. Thermal stability of the sepaated compounds have been studied. Upon heating U(HPO 3 )x2H 2 O up to 120-190 deg C, hydrate water is removed. The final product obtained on heating up to 900 deg C is identified as UP 2 O 7 . In the case of U(H 2 PO 3 ) 4 x2H 2 O, crystallization water is removed stepwise within the ranges of 60-140 deg C and 160-270 deg C. Complete removal of water yields a compound of U(H 2 P 2 O 5 ). It has been established that uranium phosphites are isomorphous to the corresponding thorium phosphites

  18. Green synthesis of silver nanoparticles and silver colloidal solutions

    International Nuclear Information System (INIS)

    Nguyen Thi Phuong Phong; Ngo Hoang Minh; Ngo Vo Ke Thanh; Dang Mau Chien

    2009-01-01

    In this paper, silver colloidal solutions have been synthesized rapidly in green conditions by using microwave irradiation and non-toxic chemistry substances (acid oxalic, silver nitrate, polyvinyl pyrolidone (PVP; Mw = 55 000)). The particle size and morphology of these solutions can be controlled by altering several factors like the time, the power of microwave exposure, and the ratio of silver oxalate and PVP etc. The silver nanoparticles were fabricated by thermal decomposition of silver oxalate. The synthesized silver colloidal solutions and silver nanoparticles were characterized by several analytical techniques like UV- VIS, XRD, TEM, FESEM/EDS and ICP-AAS studies. Finally, we used the synthesized silver colloidal solutions for antibacterial purpose. The obtained results showed that the synthesized silver colloidal solutions, even at very low concentrations, have highly efficient anti-bacterial property.

  19. Transmission electron microscopy for elucidating the impact of silver-based treatments (ionic silver versus nanosilver-containing coating) on the model yeast Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Despax, B; Saulou, C; Raynaud, P [Universite de Toulouse, UPS, INPT, LAPLACE, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); Datas, L [Universite de Toulouse, UPS, INPT, CIRIMAT, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); Mercier-Bonin, M [Universite de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France)

    2011-04-29

    After exposure to ionic silver or nanosilver-containing plasma coating, the same visual aspect of scanning transmission electron microscopy (STEM) images was observed for the model yeast Saccharomyces cerevisiae. The main common feature was the presence of electron-dense nodules all over the cell. However, high resolution TEM (HRTEM), STEM, energy dispersive x-ray microanalysis spectroscopy (EDS) and electron microdiffraction revealed some striking differences. Regarding ionic silver exposure, the formation of electron-dense nodules was related to the Ag{sup +} reactivity towards sulfur-containing compounds to form clusters with Ag{sub 2}S-like structures, together with the production of a few silver nanocrystals, mainly at the cell wall periphery. For nanosilver-based treatment, some sulfur-containing silver clusters preferentially located at the cell wall periphery were detected, together with nodules composed of silver, sulfur and phosphorus all over the cell. In both silver-based treatments, nitrogen and silver signals overlapped, confirming the affinity of silver entities for proteinaceous compounds. Moreover, in the case of nanosilver, interactions of silver with phosphorus-containing subcellular structures were indicated.

  20. Uranium decontamination of common metals by smelting, a review (handbook)

    International Nuclear Information System (INIS)

    Mautz, E.W.; Briggs, G.G.; Shaw, W.E.; Cavendish, J.H.

    1975-01-01

    The published and unpublished literature relating to the smelting of common metals scrap contaminated with uranium-bearing compounds has been searched and reviewed. In general, standard smelting practice produces ingots having a low uranium content, particularly for ferrous, nickel, and copper metals or alloys. Aluminum recovered from uranium contaminated scrap shows some decontamination by smelting but the uranium content is not as low as for other metals. Due to the heterogeneous nature and origin of scrap metals contaminated with uranium, information is frequently missing as to the extent of the initial contamination and the degree of decontamination obtained. The uranium content of the final cast ingots is generally all that is available. Results are summarized below by the primary composition of the uranium contaminated scrap metal. (U.S.)

  1. Provision by the uranium and uranium products

    International Nuclear Information System (INIS)

    Elagin, Yu.P.

    2005-01-01

    International uranium market is converted from the buyer market into the seller market. The prices of uranium are high and the market attempts to adapt to changing circumstances. The industry of uranium enrichment satisfies the increasing demands but should to increase ots capacities. On the whole the situation is not stable and every year may change the existing position [ru

  2. Uranium recovery from slags of metallic uranium

    International Nuclear Information System (INIS)

    Fornarolo, F.; Frajndlich, E.U.C.; Durazzo, M.

    2006-01-01

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

  3. Recent developments in Australia's uranium mining industry

    International Nuclear Information System (INIS)

    McKay, A.D.

    2001-01-01

    Uranium is produced at two mining/milling operations in Australia - Ranger in the Alligator Rivers Region of the Northern Territory, and Olympic Dam in South Australia. In 1996, Ranger produced 4138 tonnes (t) U 3 O 8 from stockpiled ore mined from Ranger No. 1 Orebody. The capacity of the Ranger mill is being expanded to 5000 tonnes per annum (tpa) U 3 O 8 to coincide with the commencement of mining from No. 3 Orebody in mid-1997. The Olympic Dam copper-uranium-gold-silver deposit is the world's largest deposit of low cost uranium. The operation currently has an annual production of 85,000 t copper, 1700 t U 3 O 8 and associated gold and silver. WMC Ltd proposes to expand annual production to 200 000 t copper and approximately 4600 t U 3 O 8 by end of 1999. The environmental impact of the expansion is being assessed jointly by both Commonwealth and South Australian Governments. A draft Environmental Impact Statement (EIS) was released in May. Since its election in March 1996, the Liberal/National Party Coalition Government has made a number of changes to the Commonwealth Government's policies relating to uranium mining, including removal of the former Government's 'three mines' policy, and relaxation of the guidelines for foreign investment in Australian uranium mines. These changes, together with an improved outlook for the uranium market, have resulted in proposals to develop new mines at Jabiluka (Northern Territory), Kintyre (Western Australia) and Beverley (South Australia). Energy Resources of Australia Ltd proposes to develop an underground mine at Jabiluka with the ore to be processed at Ranger mill. Initial production will be 1800 tpa U 3 O 8 which will increase to 4000 tpa U 3 O 8 by the 14th year. The draft EIS was released for public comment in October 1996, and the final EIS is to be released in June 1997. Canning Resources Ltd proposes to mine the Kintyre deposit by open cut methods commencing in 1999 with an annual production of 1200 tpa U 3 O 8

  4. Phosphorus and uranium recovery process from phosphated rocks

    Energy Technology Data Exchange (ETDEWEB)

    Sze, M C.Y.; Long, R H

    1981-01-30

    Improvement of uranium recovery in phosphate rocks by treatment with nitric acid avoiding the formation of a precipitate including a part of the uranium. The separation of uranium from phosphoric acid is obtained by liquid-liquid extraction using dialkyl posphoric acid with at least 10 carbon atoms and a phosphoryl alkyl alkoxy compound with at least 10 carbon atoms and a non water miscible organic solvent.

  5. Laser separation of uranium isotopes

    International Nuclear Information System (INIS)

    Porter, J.T.

    1981-01-01

    Method and apparatus for separating uranium isotopes are claimed. The method comprises the steps of irradiating a uranyl source material at a wavelength selective to a desired isotope and at an effective temperature for isotope spectral line splitting below about 77 deg.K., further irradiating the source material within the fluorescent lifetime of the source material to selectively photochemically reduce the excited isotopic species, and chemically separating the reduced isotope species from the remaining uranyl salt compound

  6. Uranium enrichment

    International Nuclear Information System (INIS)

    Mohrhauer, H.

    1982-01-01

    The separation of uranium isotopes in order to enrich the fuel for light water reactors with the light isotope U-235 is an important part of the nuclear fuel cycle. After the basic principals of isotope separation the gaseous diffusion and the centrifuge process are explained. Both these techniques are employed on an industrial scale. In addition a short review is given on other enrichment techniques which have been demonstrated at least on a laboratory scale. After some remarks on the present situation on the enrichment market the progress in the development and the industrial exploitation of the gas centrifuge process by the trinational Urenco-Centec organisation is presented. (orig.)

  7. Sponge-like silver obtained by decomposition of silver nitrate hexamethylenetetramine complex

    Energy Technology Data Exchange (ETDEWEB)

    Afanasiev, Pavel, E-mail: pavel.afanasiev@ircelyon.univ-lyon.fr

    2016-07-15

    Silver nitrate hexamethylenetetramine [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] coordination compound has been prepared via aqueous route and characterized by chemical analysis, XRD and electron microscopy. Decomposition of [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] under hydrogen and under inert has been studied by thermal analysis and mass spectrometry. Thermal decomposition of [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] proceeds in the range 200–250 °C as a self-propagating rapid redox process accompanied with the release of multiple gases. The decomposition leads to formation of sponge-like silver having hierarchical open pore system with pore size spanning from 10 µm to 10 nm. The as-obtained silver sponges exhibited favorable activity toward H{sub 2}O{sub 2} electrochemical reduction, making them potentially interesting as non-enzyme hydrogen peroxide sensors. - Graphical abstract: Thermal decomposition of silver nitrate hexamethylenetetramine coordination compound [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] leads to sponge like silver that possesses open porous structure and demonstrates interesting properties as an electrochemical hydrogen peroxide sensor. Display Omitted - Highlights: • [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] orthorhombic phase prepared and characterized. • Decomposition of [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] leads to metallic silver sponge with opened porosity. • Ag sponge showed promising properties as a material for hydrogen peroxide sensors.

  8. Issues in uranium availability

    International Nuclear Information System (INIS)

    Schanz, J.J. Jr.; Adams, S.S.; Gordon, R.L.

    1982-01-01

    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

  9. Australian uranium industry

    Energy Technology Data Exchange (ETDEWEB)

    Warner, R K

    1976-04-01

    Various aspects of the Australian uranium industry are discussed including the prospecting, exploration and mining of uranium ores, world supply and demand, the price of uranium and the nuclear fuel cycle. The market for uranium and the future development of the industry are described.

  10. Irradiated uranium reprocessing

    International Nuclear Information System (INIS)

    Gal, I.

    1961-12-01

    Task concerned with reprocessing of irradiated uranium covered the following activities: implementing the method and constructing the cell for uranium dissolving; implementing the procedure for extraction of uranium, plutonium and fission products from radioactive uranium solutions; studying the possibilities for using inorganic ion exchangers and adsorbers for separation of U, Pu and fission products

  11. 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

  12. Recovering uranium from phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Bergeret, M [Compagnie de Produits Chimiques et Electrometallurgiques Pechiney-Ugine Kuhlmann, 75 - Paris (France)

    1981-06-01

    Processes for the recovery of the uranium contained in phosphates have today become competitive with traditional methods of working uranium sources. These new possibilities will make it possible to meet more rapidly any increases in the demand for uranium: it takes ten years to start working a new uranium deposit, but only two years to build a recovery plant.

  13. Uranium enrichment plans

    International Nuclear Information System (INIS)

    Gagne, R.W.; Thomas, D.C.

    1977-01-01

    The status of existing uranium enrichment contracts in the US is reviewed and expected natural uranium requirements for existing domestic uranium enrichment contracts are evaluated. Uncertainty in natural uranium requirements associated with requirements-type and fixed-commitment type contracts is discussed along with implementation of variable tails assay

  14. Uranium enrichment plans

    International Nuclear Information System (INIS)

    Thomas, D.C.; Gagne, R.W.

    1978-01-01

    The following topics are covered: the status of the Government's existing uranium enrichment services contracts, natural uranium requirements based on the latest contract information, uncertainty in predicting natural uranium requirements based on uranium enrichment contracts, and domestic and foreign demand assumed in enrichment planning

  15. Generation of Hybrid Peptide-Silver Nanoparticles for Antibacterial and Antifouling Applications

    KAUST Repository

    Seferji, Kholoud

    2018-01-01

    and antifouling agents. Our innovative antibacterial agents are hybrid peptide silver nanoparticles (CH-01-AgNPs) that are created de novo and in situ from a silver nitrate solution (AgNO3) in the presence of ultrashort self-assembling peptides compounds

  16. Uranium nucleophilic carbene complexes

    International Nuclear Information System (INIS)

    Tourneux, Jean-Christophe

    2012-01-01

    The only stable f-metal carbene complexes (excluding NHC) metals f present R 2 C 2- 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{Ph 2 P(=S)} 2 2- (SCS 2- ) 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 M 2 SCS (M = Li, K, Tl) which is transformed into LiSCHS in THF or into product of intramolecular cyclization K 2 [C(PhPS) 2 (C 6 H 4 )]. We have developed the necessary conditions mono-, bis- and tris-carbene directly from the di-anion SCS 2- and UCl 4 , as the precursor used in uranium chemistry. The protonolysis reactions of amides compounds (U-NEt 2 ) by the neutral ligand SCH 2 S were also studied. The compounds [Li(THF)] 2 [U(SCS)Cl 3 ] and [U(SCS)Cl 2 (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)Cl 2 (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 C 5 H 5 - 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), [UO 2 (SCS)(THF) 2 ], was isolated with the uranyl ion UO 2 2+ . The reactions of compounds UO 2 X 2

  17. Uranium induces oxidative stress in lung epithelial cells

    International Nuclear Information System (INIS)

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

    2007-01-01

    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 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.)

  18. Uranium industry annual 1985

    International Nuclear Information System (INIS)

    1986-11-01

    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

  19. Uranium industry framework

    International Nuclear Information System (INIS)

    Riley, K.

    2008-01-01

    The global uranium market is undergoing a major expansion due to an increase in global demand for uranium, the highest uranium prices in the last 20 years and recognition of the potential greenhouse benefits of nuclear power. Australia holds approximately 27% of the world's uranium resources (recoverable at under US$80/kg U), so is well placed to benefit from the expansion in the global uranium market. Increasing exploration activity due to these factors is resulting in the discovery and delineation of further high grade uranium deposits and extending Australia's strategic position as a reliable and safe supplier of low cost uranium.

  20. Method for preparing a sinterable uranium dioxide powder

    International Nuclear Information System (INIS)

    Thornton, T.A.; Holaday, V.D. Jr.

    1985-01-01

    This invention provides an improved method for preparing a sinterable uranium dioxide powder for the preparation of nuclear fuel, using microwave radiation in a microwave induction furnace. The starting compound may be uranyl nitrate hexahydrate, ammonium diuranate or ammonium uranyl carbonate. The starting compound is heated in a microwave induction furnace for a period of time sufficient for compound decomposition. The decomposed compound is heated in a microwave induction furnace in a reducing atmosphere for a period of time sufficient to reduce the decomposed compound to uranium dioxide powder

  1. Debye temperatures of uranium chalcogenides from their lattice ...

    Indian Academy of Sciences (India)

    Phonon dispersion relations in uranium chalcogenides have been investigated using a modified three-body force shell model. From the phonon frequencies, their Debye temperatures are evaluated. Further, on the basis of the spin fluctuation in the heavy fermion uranium compounds, UPt3 and UBe13, the possible ...

  2. Reduction of uranium hexafluoride to uranium tetrafluoride

    International Nuclear Information System (INIS)

    Chang, I.S.; Do, J.B.; Choi, Y.D.; Park, M.H.; Yun, H.H.; Kim, E.H.; Kim, Y.W.

    1982-01-01

    The single step continuous reduction of uranium hexafluoride (UF 6 ) to uranium tetrafluoride (UF 4 ) has been investigated. Heat required to initiate and maintain the reaction in the reactor is supplied by the highly exothermic reaction of hydrogen with a small amount of elemental fluorine which is added to the uranium hexafluoride stream. When gases uranium hexafluoride and hydrogen react in a vertical monel pipe reactor, the green product, UF 4 has 2.5g/cc in bulk density and is partly contaminated by incomplete reduction products (UF 5 ,U 2 F 9 ) and the corrosion product, presumably, of monel pipe of the reactor itself, but its assay (93% of UF 4 ) is acceptable for the preparation of uranium metal with magnesium metal. Remaining problems are the handling of uranium hexafluoride, which is easily clogging the flowmeter and gas feeding lines because of extreme sensitivity toward moisture, and a development of gas nozzel for free flow of uranium hexafluoride gas. (Author)

  3. Standard enthalpies of formation of uranium compounds

    International Nuclear Information System (INIS)

    Cordfunke, E.H.P.; Ouweltjes, W.

    1977-01-01

    Enthalpies of solution of β-UO 2 SO 4 and α-UO 2 SeO 4 in H 2 SO 4 (aq) and of UO 2 SeO 3 in H 2 SO 4 (aq) + Ce(SO 4 ) 2 have been measured calorimetrically. Together with measurements of the enthalpy of solution of γ-UO 3 in these solvents, the standard enthalpies of formation of anhydrous β-UO 2 SO 4 , α-UO 2 SeO 4 , and UO 2 SeO 3 have been derived. The results obtained are: ΔHsub(f) 0 (s, 298.15 K)/ kcalsub(th) mol -1 : β-UO 2 SO 4 , -(440.9 +- 0.2); α-UO 2 SeO 4 , -(367.9 +- 0.8); UO 2 SeO 3 , -(363.8 +- 0.2). (author)

  4. Study of reactions between uranium-plutonium mixed oxide and uranium nitride and between uranium oxide and uranium nitride; Etude des reactions entre l`oxyde mixte d`uranium-plutonium et le nitrure d`uranium et entre l`oxyde d`uranium et le nitrure d`uranium

    Energy Technology Data Exchange (ETDEWEB)

    Lecraz, C

    1993-06-11

    A new type of combustible elements which is a mixture of uranium nitride and uranium-plutonium oxide could be used for Quick Neutrons Reactors. Three different studies have been made on the one hand on the reactions between uranium nitride (UN) and uranium-plutonium mixed oxide (U,Pu)O{sub 2}, on the other hand on these between UN and uranium oxide UO{sub 2}. They show a sizeable reaction between nitride and oxide for the studied temperatures range (1573 K to 1973 K). This reaction forms a oxynitride compound, MO{sub x} N{sub y} with M=U or M=(U,Pu), whose crystalline structure is similar to oxide`s. Solubility of nitride in both oxides is studied, as the reaction kinetics. (TEC). 32 refs., 48 figs., 22 tabs.

  5. Uranium - the world picture

    International Nuclear Information System (INIS)

    Silver, J.M.; Wright, W.J.

    1976-01-01

    The world resources of uranium and the future demand for uranium are discussed. The amount of uranium available depends on the price which users are prepared to pay for its recovery. As the price is increased, there is an incentive to recover uranium from lower grade or more difficult deposits. In view of this, attention is drawn to the development of the uranium industry in Australias

  6. Carboxylate and amino group coated silver nanoparticles as joining materials for copper-to-copper silver joints.

    Science.gov (United States)

    Oestreicher, A; Röhrich, T; Lerch, M

    2012-12-01

    Organic silver complexes are introduced where silver is linked either with a carboxyl group or with an amino group. Upon heating, nanoparticles are generated if the respective ligands are long enough to act as stabilizing agents in the nanoparticulate regime. With decomposition and volatilization of the organic material, the sintering of silver occurs. The thermal characteristics of the carboxylates silver-n-octanoate, silver-n-decanoate, and AgOOC(CH2OCH2)2CH2OCH3 are compared with silver-n-alkylamines (n = 8, 9, and 12), and their thermal behavior is discussed based on thermogravimetry (TG) measurements. The consecutive stages of a metallization process are addressed based on the properties of AgOOC(CH2OCH2)2CH2OCH3, and the usable effects of the individual phases of this metal organic compound are analyzed by cross-sectional scanning electron microscope (SEM) images of silver joints. Selection criteria are addressed based on the thermal behavior. A mechanism for the joining process is proposed, considering formation and sintering of the nanoparticles. It was found that the bulk material can be used for low-temperature joining processes. Strong adherence to copper as a basic material can be achieved.

  7. Silver nanostructures in laser desorption/ionization mass spectrometry and mass spectrometry imaging.

    Science.gov (United States)

    Sekuła, Justyna; Nizioł, Joanna; Rode, Wojciech; Ruman, Tomasz

    2015-09-21

    Silver nanoparticles have been successfully applied as a matrix replacement for the laser desorption/ionization time-of-flight mass spectrometry (LDI-ToF-MS). Nanoparticles, producing spectra with highly reduced chemical background in the low m/z region, are perfectly suited for low-molecular weight compound analysis and imaging. Silver nanoparticles (AgNPs) can efficiently absorb ultraviolet laser radiation, transfer energy to the analyte and promote analyte desorption, but also constitute a source of silver ions suitable for analyte cationisation. This review provides an overview of the literature on silver nanomaterials as non-conventional desorption and ionization promoters in LDI-MS and mass spectrometry imaging.

  8. Enthalpies of vaporization of organometallic compounds

    International Nuclear Information System (INIS)

    Kuznetsov, N.T.; Sevast'yanov, V.G.; Mitin, V.A.; Krasnodubskaya, S.V.; Zakharov, L.N.; Domrachev, G.A.; AN SSSR, Gor'kij. Inst. Khimii)

    1987-01-01

    A possibility to use the method of additive schemes for the calculation of vaporizaton enthalpies of uranium organometallic compounds is discussed while comparing the values obtained using the method with experimental data. The possibility of apriori evaluation of evaporation enthalpy values of different uranium compounds using the method of additive schemes and structural characteristics of molecules, such as the sum of ligand solid angles, is shown

  9. Natural uranium

    International Nuclear Information System (INIS)

    Ammerich, Marc; Frot, Patricia; Gambini, Denis-Jean; Gauron, Christine; Moureaux, Patrick; Herbelet, Gilbert; Lahaye, Thierry; Pihet, Pascal; Rannou, Alain

    2014-08-01

    This sheet belongs to a collection which relates to the use of radionuclides essentially in unsealed sources. Its goal is to gather on a single document the most relevant information as well as the best prevention practices to be implemented. These sheets are made for the persons in charge of radiation protection: users, radioprotection-skill persons, labor physicians. Each sheet treats of: 1 - the radio-physical and biological properties; 2 - the main uses; 3 - the dosimetric parameters; 4 - the measurement; 5 - the protection means; 6 - the areas delimitation and monitoring; 7 - the personnel classification, training and monitoring; 8 - the effluents and wastes; 9 - the authorization and declaration administrative procedures; 10 - the transport; and 11 - the right conduct to adopt in case of incident or accident. This sheet deals specifically with natural uranium

  10. A short history of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Habashi, F., E-mail: Fathi.Habashi@arul.ulaval.ca [Laval Univ., Dept. of Mining, Metallurgical, and Materials Engineering, Quebec City, QC (Canada)

    2010-07-01

    Joachimsthal in Saxony was an important silver mining district since the Middle Ages when around the 1770s production started to decrease and the mining town was about to become a ghost town. It was at that time that Martin Heinrich Klaproth (1743-1817) a pharmacist in Berlin who later became a professor of chemistry at the Royal Mining Academy, discovered that the black mineral in the ore can be used to give glass a brilliant yellow color with green fluorescence when added to the molten batch. He was also convinced that this mineral must have contained a new metal. This discovery coincided with the discovery in 1781 of a new planet in the solar system by his compatriot William Herschel who had immigrated to England in 1757 and called the planet Uranus. Hence Klaproth named the new metal 'uranium' to honor his compatriot. In 1789, he was able to isolate a black heavy solid from the ore which he thought to be the new metal. Since that time uranium started to play a dominant role in the history of civilization that will be told briefly. (author)

  11. Uranium geochemical exploration in northwestern Luzon

    International Nuclear Information System (INIS)

    Santos, G. Jr.; Fernandez, L.; Ogena, M.; Tauli, G.

    1980-01-01

    A reconnaissance geochemical stream water and sediment survey which was conducted in northwestern Luzon was able to detect ten (10) uranium anomalous areas. These anomalous areas are located along a north-south trending zone of Miocene marine clastics and sedimentary rocks with tuffaceous sediment intercalations. In general, northwest Luzon has low radioactivity except for two anomalous areas which have 3 to 6 times background radioactivity. Radon anomalies occur in sparsely scattered locations. The anomalous zones appear to be related to major north-south faults and secondary northeast-southwest trending structures. Geochemical correlations between uranium and other elements such as copper, lead, zinc, manganese, silver, cobalt and nickel are generally very poor. (author)

  12. Determination of uranium in clinical and environmental samples by FIAS-ICPMS

    International Nuclear Information System (INIS)

    Karpas, Z.; Lorber, A.; Halicz, L.; Gavrieli, I.

    1998-01-01

    Uranium may enter the human body through ingestion or inhalation. Ingestion of uranium compounds through the diet, mainly drinking water, is a common occurrence, as these compounds are present in the biosphere. Inhalation of uranium-containing particles is mainly an occupational safety problem, but may also take place in areas where uranium compounds are abundant. The uranium concentration in urine samples may serve as an indication of the total uranium body content. A method based on flow injection and inductively coupled plasma mass spectrometry (FIAS-ICPMS) was found to be most suitable for determination of uranium in clinical samples (urine and serum), environmental samples (seawater, wells and carbonate rocks) and in liquids consumed by humans (drinking water and commercial beverages). Some examples of the application of the FIAS-ICPMS method are reviewed and presented here

  13. Chapter 1. General information about uranium. 1.10. Uranium application

    International Nuclear Information System (INIS)

    Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

    2011-01-01

    Full text: Metallic uranium or its compounds are used as nuclear fuel in nuclear reactors. A natural or low-enriched admixture of uranium isotopes is applied in stationery reactors of nuclear power plants, and products of a high enrichment degree are used in nuclear power plants or in reactors that operates with fast neutrons. 235 U is a source of nuclear energy in nuclear weapons. Depleted uranium is used as armour-piercing core in bombshells. 238 U serves as a source of secondary nuclear fuel - plutonium. (author)

  14. Chapter 1. General information about uranium. 1.10. Uranium application

    International Nuclear Information System (INIS)

    Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

    2012-01-01

    Full text: Metallic uranium or its compounds are used as nuclear fuel in nuclear reactors. A natural or low-enriched admixture of uranium isotopes is applied in stationery reactors of nuclear power plants, and products of a high enrichment degree are used in nuclear power plants or in reactors that operates with fast neutrons. 235 U is a source of nuclear energy in nuclear weapons. Depleted uranium is used as armour-piercing core in bombshells. 238 U serves as a source of secondary nuclear fuel - plutonium.

  15. Some potential strategies for the treatment of waste uranium metal and uranium alloys

    International Nuclear Information System (INIS)

    Burns, C.J.; Frankcom, T.M.; Gordon, P.L.; Sauer, N.N.

    1993-01-01

    Large quantities of uranium metal chips and turnings stored throughout the DOE Complex represent a potential hazard, due to the reactivity of this material toward air and water. Methods are being sought to mitigate this by conversion of the metal, via room temperature solutions routes, to a more inert oxide form. In addition, the recycling of uranium and concomitant recovery of alloying metals is a desirable goal. The emphasis of the authors' research is to explore a variety of oxidation and reduction pathways for uranium and its compounds, and to investigate how these reactions might be applied to the treatment of bulk wastes

  16. Leaching of Silver from Silver-Impregnated Food Storage Containers

    Science.gov (United States)

    Hauri, James F.; Niece, Brian K.

    2011-01-01

    The use of silver in commercial products has proliferated in recent years owing to its antibacterial properties. Food containers impregnated with micro-sized silver promise long food life, but there is some concern because silver can leach out of the plastic and into the stored food. This laboratory experiment gives students the opportunity to…

  17. Precise micropatterning of silver nanoparticles on plastic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Ammosova, Lena; Jiang, Yu; Suvanto, Mika; Pakkanen, Tapani A., E-mail: tapani.pakkanen@uef.fi

    2017-04-15

    Highlights: • Silver ink has been deposited on plastic substrate and silver nanoparticles have been produced. • 3D control allows both ink superimposing and deposition on complicated surfaces. • Polyol method ensures the formation of metallic mircopatterns with high uniformity. • Substrate wettability, ink volume, and sintering temperature influences deposited patterns. - Abstract: Conventional fabrication methods to obtain metal patterns on polymer substrates are restricted by high operating temperature and complex preparation steps. The present study demonstrates a simple yet versatile method for preparation of silver nanoparticle micropatterns on polymer substrates with various surface geometry. With the microworking robot technique, we were able not only to directly structure the surface, but also precisely deposit silver nanoparticle ink on the desired surface location with the minimum usage of ink material. The prepared silver nanoparticle ink, containing silver cations and polyethylene glycol (PEG) as a reducing agent, yields silver nanoparticle micropatterns on plastic substrates at low sintering temperature without any contamination. The influence of the ink behaviour was studied, such as substrate wettability, ink volume, and sintering temperature. The ultraviolet visible (UV–vis), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) measurements revealed the formation of micropatterns with uniformly distributed silver nanoparticles. The prepared patterns are expected to have a broad range of applications in optics, medicine, and sensor devices owing to the unique properties of silver. Furthermore, the deposition of a chemical compound, which is different from the substrate material, not only adds a fourth dimension to the prestructured three-dimensional (3D) surfaces, but also opens new application areas to the conventional surface structures.

  18. Precise micropatterning of silver nanoparticles on plastic substrates

    International Nuclear Information System (INIS)

    Ammosova, Lena; Jiang, Yu; Suvanto, Mika; Pakkanen, Tapani A.

    2017-01-01

    Highlights: • Silver ink has been deposited on plastic substrate and silver nanoparticles have been produced. • 3D control allows both ink superimposing and deposition on complicated surfaces. • Polyol method ensures the formation of metallic mircopatterns with high uniformity. • Substrate wettability, ink volume, and sintering temperature influences deposited patterns. - Abstract: Conventional fabrication methods to obtain metal patterns on polymer substrates are restricted by high operating temperature and complex preparation steps. The present study demonstrates a simple yet versatile method for preparation of silver nanoparticle micropatterns on polymer substrates with various surface geometry. With the microworking robot technique, we were able not only to directly structure the surface, but also precisely deposit silver nanoparticle ink on the desired surface location with the minimum usage of ink material. The prepared silver nanoparticle ink, containing silver cations and polyethylene glycol (PEG) as a reducing agent, yields silver nanoparticle micropatterns on plastic substrates at low sintering temperature without any contamination. The influence of the ink behaviour was studied, such as substrate wettability, ink volume, and sintering temperature. The ultraviolet visible (UV–vis), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) measurements revealed the formation of micropatterns with uniformly distributed silver nanoparticles. The prepared patterns are expected to have a broad range of applications in optics, medicine, and sensor devices owing to the unique properties of silver. Furthermore, the deposition of a chemical compound, which is different from the substrate material, not only adds a fourth dimension to the prestructured three-dimensional (3D) surfaces, but also opens new application areas to the conventional surface structures.

  19. Preparation of uranium ingots from double fluorides

    International Nuclear Information System (INIS)

    Le Boulbin, E.

    1967-05-01

    A simple method has been developed for the preparation of uranium double fluorides and has given a new impetus to the study of the reduction of these compounds with a view to obtaining very pure uranium ingots. This reduction can be carried out using calcium or magnesium as the reducing agent, this latter metal being very interesting from the practical point of view. A comparative study of the heat balances of the reduction processes for the double fluorides and for uranium tetrafluoride has shown that reduction of the double fluorides is possible. The exact experimental conditions for these reductions have been determined. Our study has shown in particular that the reduction of the double salt UF 4 , CaF 2 by magnesium leads to the production of small (20 to 500 g) samples of high-purity uranium with a yield of 99 per cent. (author) [fr

  20. Silver enhancement of nanogold and undecagold

    Energy Technology Data Exchange (ETDEWEB)

    Hainfield, J.F.; Furuya, F.R.

    1995-07-01

    A recent advance in immunogold technology has been the use of molecular gold instead of colloidal gold. A number of advantages are realized by this approach, such as stable covalent, site-specific attachment, small probe size and absence of aggregates for improved penetration. Silver enhancement has led to improved and unique results for electron and light microscopy, as well as their use with blots and gels. Most previous work with immunogold silver staining has been done with colloidal gold particles. More recently, large gold compounds (``clusters``) having a definite number of gold atoms and defined organic shell, have been used, frequently with improved results. These gold dusters, large compared to simple compounds, are, however, at the small end of the colloidal gold scale in size; undecagold is 0.8 nm and Nanogold is 1.4 nm. They may be used in practically all applications where colloidal gold is used (Light and electron microscopy, dot blots, etc.) and in some unique applications, where at least the larger colloidal golds don`t work, such as running gold labeled proteins on gels (which are later detected by silver enhancement). The main differences between gold clusters and colloidal golds are the small size of the dusters and their covalent attachment to antibodies or other molecules.

  1. Uranium management activities

    International Nuclear Information System (INIS)

    Jackson, D.; Marshall, E.; Sideris, T.; Vasa-Sideris, S.

    2001-01-01

    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)

  2. Uranium industry annual 1998

    International Nuclear Information System (INIS)

    1999-01-01

    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

  3. Uranium industry annual 1994

    International Nuclear Information System (INIS)

    1995-01-01

    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

  4. Why jurisdiction and uranium deposit type are essential considerations for exploration and mining of uranium

    International Nuclear Information System (INIS)

    Miller, D.

    2014-01-01

    Uranium is a relatively abundant element, being 25 times more common than silver, and having the same crustal abundance as tin. Economically minable uranium grades vary greatly, from a low of 0.01% U to over 20% U. What are the factors that allow mining of these very low grade ores that are only 50 times background concentrations? Why don’t the high grade deposits of the world exclusively supply all of the worlds newly mined uranium needs? There are two main reasons that the high grade deposits of the world do not exclusively supply all of the worlds newly mined uranium needs: 1) jurisdictional issues, the favorability or lack thereof of governmental policies where the deposit is located and the delays caused by an ineffective or corrupt policy and 2) the deposit type, which has a great influence on the recovery cost of the uranium. The quality of a deposit can override more difficult political jurisdictions if recovery of the investment occurs quickly and in an environmentally friendly way.

  5. Comparison on Bactericidal and Cytotoxic Effect of Silver Nanoparticles Synthesized by Different Methods

    Science.gov (United States)

    Mala, R.; Celsia, A. S. Ruby; Malathi Devi, S.; Geerthika, S.

    2017-08-01

    Biologically synthesized silver nanoparticle are biocompatible for medical applications. The present work is aimed to synthesize silver nanoparticle using the fruit pulp of Tamarindusindica and to evaluate its antibacterial and anticancer activity against lung cancercell lines. Antibacterial activity was assessed by well diffusion method. Cytotoxicity was evaluated using MTT assay. GC-MS of fruit pulp extract showed the presence of levoglucosenone, n-hexadecanoic acid, 9,12-octadecadienoic acid etc. Antioxidant activity of the fruit pulp was determined by DPPH assay, hydrogen peroxide scavenging assay and lipid peroxidation. The size of biologically synthesized silver nanoparticle varied from 50 nm to 76 nm. It was 59 nm to 98 nm for chemically synthesized silver nanoparticle. Biologically synthesized silver nanoparticle showed 26 mm inhibition zone against E. coli and chemically synthesized silver nanoparticle showed 20 mm. Antioxidant activity of fruit extract by DPPH showed 84 % reduction. The IC 50 of biologically synthesized silver nanoparticle against lung cancer cell lines was 48 µg/ml. It was 95 µg/ml for chemically synthesized silver nanoparticle. The increased activity of biologically synthesized silver nanoparticle was due to its smaller size, stability and the bioactive compounds capping the silver nanoparticle extracted from the fruit extract.

  6. Uranium: a basic evaluation

    International Nuclear Information System (INIS)

    Crull, A.W.

    1978-01-01

    All energy sources and technologies, including uranium and the nuclear industry, are needed to provide power. Public misunderstanding of the nature of uranium and how it works as a fuel may jeopardize nuclear energy as a major option. Basic chemical facts about uranium ore and uranium fuel technology are presented. Some of the major policy decisions that must be made include the enrichment, stockpiling, and pricing of uranium. Investigations and lawsuits pertaining to uranium markets are reviewed, and the point is made that oil companies will probably have to divest their non-oil energy activities. Recommendations for nuclear policies that have been made by the General Accounting Office are discussed briefly

  7. Uranium health physics

    International Nuclear Information System (INIS)

    1980-01-01

    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

  8. Uranium: one utility's outlook

    International Nuclear Information System (INIS)

    Gass, C.B.

    1983-01-01

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

  9. Improving the Vase life of Cut Carnation ‘Tempo’ (Dianthus carryophyllusL. Flower by Silver Thiosulphate and Silver Nano-Particles

    Directory of Open Access Journals (Sweden)

    D. Hashemabadi

    2014-08-01

    Full Text Available Nanometer-sized silver particle can be act as an anti-microbial compound. Thus, in this research, the efficacy of silver thiosulphate and silver nano-particles as antimicrobial agents in extending the vase-life of cut carnation flowers was evaluated. A factorial experiment carried out based on randomized completely blocks design with two factors: silver thiosulphate (0, 0.1, 0.2 and 0.3 mM and silver nano-particles (0, 5, 10 and 15 mg/L. Mean comparison of the data showed that the combined treatments of 0.3 mM silver thiosulphate + 15 mg/L silver nano-particles had the highest vase life, water uptake and super oxide dismutase enzyme. Thus, the mentioned above treatment was proposed to increase prolong vase life and improvement of water relations and control of stem end blockage. Based to results of this study, silver thiosulphate and silver nano-particles can be used for increasing postharvest longevity of cut carnation "Tempo".

  10. Interim guidance for the safe transport of reprocessed uranium

    International Nuclear Information System (INIS)

    1994-06-01

    Increasingly reprocessed uranium is being used for the fabrication of nuclear fuel elements. Different intermediate reprocessing steps are carried out at different locations. Therefore, transportation of uranium material is necessary. Due to the difference in isotope composition of reprocessed uranium then unirradiated uranium a doubt is casted on the presumption that packages used for the transport of unirradiated uranium are automatically suitable for reprocessed uranium compounds. The Standing Advisory Group on the Safe Transport of Radioactive Material (SAGSTRAM) recommended that the issue be reviewed by consultants and that a document be developed that would give guidance to users of the Regulations. This TECDOC is the result of the endeavors of the experts convened at two Consultants Services meetings. It contains guidance on the provisions in the current Regulations as well as proposals for changes to the new Revised Edition whose publication is planned for 1996. This document demonstrates that under the present Transport Regulations it is possible in most cases to ship reprocessed uranium compounds in the same packages as unirradiated uranium compounds. In few cases a more stringent package type is required. 8 refs, 22 figs, 19 tabs

  11. Recovery of uranium from crude uranium tetrafluoride

    International Nuclear Information System (INIS)

    Ghosh, S.K.; Bellary, M.P.; Keni, V.S.

    1994-01-01

    An innovative process has been developed for recovery of uranium from crude uranium tetrafluoride cake. The process is based on direct dissolution of uranium tetrafluoride in nitric acid in presence of aluminium hydroxide and use of solvent extraction for removal of fluorides and other bulk impurities to make uranium amenable for refining. It is a simple process requiring minimum process step and has advantage of lesser plant corrosion. This process can be applied for processing of uranium tetrafluoride generated from various sources like uranium by-product during thorium recovery from thorium concentrate, first stage product of uranium recovery from phosphoric acid by OPPA process and off grade uranium tetrafluoride material. The paper describes the details of the process developed and demonstrated on bench and pilot scale and its subsequent modification arising out of bulky solid waste generation. The modified process uses a lower quantity of aluminium hydroxide by allowing a lower dissolution of uranium per cycle and recycles the undissolved material to the next cycle, maintaining the overall recovery at high level. This innovation has reduced the solid waste generated by a factor of four at the cost of a slightly larger dissolution vessel and its increased corrosion rate. (author)

  12. Recovery of uranium from crude uranium tetrafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, S K; Bellary, M P; Keni, V S [Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    An innovative process has been developed for recovery of uranium from crude uranium tetrafluoride cake. The process is based on direct dissolution of uranium tetrafluoride in nitric acid in presence of aluminium hydroxide and use of solvent extraction for removal of fluorides and other bulk impurities to make uranium amenable for refining. It is a simple process requiring minimum process step and has advantage of lesser plant corrosion. This process can be applied for processing of uranium tetrafluoride generated from various sources like uranium by-product during thorium recovery from thorium concentrate, first stage product of uranium recovery from phosphoric acid by OPPA process and off grade uranium tetrafluoride material. The paper describes the details of the process developed and demonstrated on bench and pilot scale and its subsequent modification arising out of bulky solid waste generation. The modified process uses a lower quantity of aluminium hydroxide by allowing a lower dissolution of uranium per cycle and recycles the undissolved material to the next cycle, maintaining the overall recovery at high level. This innovation has reduced the solid waste generated by a factor of four at the cost of a slightly larger dissolution vessel and its increased corrosion rate. (author). 4 refs., 1 fig., 3 tabs.

  13. Development of the Falea Polymetallic Uranium Project, Mali

    International Nuclear Information System (INIS)

    Ring, Bob; Freeman, Paul

    2014-01-01

    Falea project basics: • Project now owned by Denison Mines; • ANSTO Minerals working with owner and their consultant, DRA; • Located in south western Mali, West Africa, near the intersection of the Senegal and Guinea borders; • Established mining region (mainly gold); • Location on plateau favourable for underground operation; • Significant uranium, silver and copper mineralisation - different to other U deposits; • Excellent metallurical outcomes to date

  14. Silver-Russell syndrome

    Directory of Open Access Journals (Sweden)

    Shohela Akhter

    2016-08-01

    Full Text Available Silver-Russell syndrome is clinically and genetically a heterogeneous disorder. In most of the cases, etiology is unknown, only in 10% cases defect in chromosome 7 is identified. It bas distinctive facial features and asymmetric limbs. Most predominant symptom is growth failure. A case of Silver-Russell syndrome reported here who presented with growth failure, hemihypertrophy ofleft side oftbe body, dysmorphic facial profile and difficulty in speech. Counseling was done with the parents regarding the etiology, progression and outcome of the disease.

  15. Lithium alkyl anions of uranium(IV) and uranium(V)

    International Nuclear Information System (INIS)

    Sigurdson, E.R.; Wilkinson, G.

    1977-01-01

    Organouranium compounds with six or eight uranium-to-carbon sigma-bonds have been synthesized for the first time. The interaction of uranium tetrachloride with lithium alkyls in diethyl ether leads to the isolation of unstable lithium alkyluranate(IV) compounds of stoicheiometry Li 2 UR 6 .8Et 2 0 (R = Me, CH 2 SiMe 3 . Ph, and o-Me 2 NCH 2 C 6 H 4 ). These lithium salts can also be obtained with other donor solvents, such as tetrahydrofuran or NNN'N'-tetramethylethylenediamine. From uranium pentaethoxide similar lithium salts of stoicheiometry Li 3 UR 8 .3 dioxan (R = Me, CH 2 CMe 3 , and CH 2 SiMe 3 ) can be obtained. The interaction of uranium(VI) hexaisopropoxide with lithium, magnesium, or aluminium alkyls does not give compounds containing U-C bonds, but green oils, e.g. U(OPrsup(i)) 6 (MgMe 2 ) 3 , that appear to be adducts in which the oxygen atom of the isopropoxide group bound to uranium is acting as a donor. I.r. and n.m.r. spectroscopy and analytical data for the new compounds are presented. (author)

  16. Decontamination of uranium-contaminated waste oil using supercritical fluid and nitric acid

    International Nuclear Information System (INIS)

    Sung, J.; Kim, J.; Lee, Y.; Seol, J.; Ryu, J.; Park, K.

    2011-01-01

    The waste oil used in nuclear fuel processing is contaminated with uranium because of its contact with materials or environments containing uranium. Under current law, waste oil that has been contaminated with uranium is very difficult to dispose of at a radioactive waste disposal site. To dispose of the uranium-contaminated waste oil, the uranium was separated from the contaminated waste oil. Supercritical R-22 is an excellent solvent for extracting clean oil from uranium-contaminated waste oil. The critical temperature of R-22 is 96.15 deg. C and the critical pressure is 49.9 bar. In this study, a process to remove uranium from the uranium-contaminated waste oil using supercritical R-22 was developed. The waste oil has a small amount of additives containing N, S or P, such as amines, dithiocarbamates and dialkyldithiophosphates. It seems that these organic additives form uranium-combined compounds. For this reason, dissolution of uranium from the uranium-combined compounds using nitric acid was needed. The efficiency of the removal of uranium from the uranium-contaminated waste oil using supercritical R-22 extraction and nitric acid treatment was determined. (authors)

  17. Uranium production

    International Nuclear Information System (INIS)

    Jones, J.Q.

    1981-01-01

    The domestic uranium industry is in a state of stagflation. Costs continue to rise while the market for the product remains stagnant. During the last 12 months, curtailments and closures of mines and mills have eliminated over 5000 jobs in the industry, plus many more in those industries that furnish supplies and services. By January 1982, operations at four mills and the mines that furnish them ore will have been terminated. Other closures may follow, depending on cost trends, duration of current contracts, the degree to which mills have been amortized, the feasibility of placing mines on standby, the grade of the ore, and many other factors. Open-pit mines can be placed on standby without much difficulty, other than the possible cost of restoration before all the ore has been removed. There are a few small, dry, underground mines that could be mothballed; however, the major underground producers are wet sandstone mines that in most cases could not be reopened after a prolonged shutdown; mills can be mothballed for several years. Figure 8 shows the location of all the production centers in operation, as well as those that have operated or are on standby. Table 1 lists the same production centers plus those that have been deferred, showing nominal capacity of conventional mills in tons of ore per calendar day, and the industry production rate for those mills as of October 1, 1981

  18. Antibacterial potential of silver nanoparticle synthesized by marine ...

    African Journals Online (AJOL)

    Multi resistance to antibiotics is a serious and disseminated clinical problem, common to several new compounds that block the resistance mechanism. The present study aimed at the comparative study of silver nanoparticles synthesized through actinomycetes and their antimicrobial metabolites with standard antibiotic.

  19. Uranium mining in Australia

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    Known uranium deposits and the companies involved in uranium mining and exploration in Australia are listed. The status of the development of the deposits is outlined and reasons for delays to mining are given

  20. Uranium Processing Facility

    Data.gov (United States)

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

  1. Uranium in Niger

    International Nuclear Information System (INIS)

    Gabelmann, E.

    1978-03-01

    This document presents government policy in the enhancement of uranium resources, existing mining companies and their productions, exploitation projects and economical outcome related to the uranium mining and auxiliary activities [fr

  2. Price of military uranium

    International Nuclear Information System (INIS)

    Klimenko, A.V.

    1998-01-01

    The theoretical results about optimum strategy of use of military uranium confirmed by systems approach accounts are received. The numerical value of the system approach price of the highly enriched military uranium also is given

  3. Uranium market and resources

    International Nuclear Information System (INIS)

    Capus, G.; Arnold, Th.

    2004-01-01

    The controversy about the extend of the uranium resources worldwide is still important, this article sheds some light on this topic. Every 2 years IAEA and NEA (nuclear energy agency) edit an inventory of uranium resources as reported by contributing countries. It appears that about 4.6 millions tons of uranium are available at a recovery cost less than 130 dollars per kg of uranium and a total of 14 millions tons of uranium can be assessed when including all existing or supposed resources. In fact there is enough uranium to sustain a moderate growth of the park of nuclear reactors during next decades and it is highly likely that the volume of uranium resources can allow a more aggressive development of nuclear energy. It is recalled that a broad use of the validated breeder technology can stretch the durability of uranium resources by a factor 50. (A.C.)

  4. Uranium from phosphate ores

    International Nuclear Information System (INIS)

    Hurst, F.J.

    1983-01-01

    The following topics are described briefly: the way phosphate fertilizers are made; how uranium is recovered in the phosphate industry; and how to detect covert uranium recovery operations in a phsophate plant

  5. Industrial realities: Uranium

    International Nuclear Information System (INIS)

    Thiron, H.

    1990-01-01

    In this special issue are examined ores and metals in France and in the world for 1988. The chapter on uranium gives statistical data on the uranium market: Demand, production, prices and reserves [fr

  6. Brazilian uranium deposits

    International Nuclear Information System (INIS)

    Santos, L.C.S. dos.

    1985-01-01

    Estimatives of uranium reserves carried out in Figueira, Itataia, Lagoa Real and Espinharas, in Brazil are presented. The samples testing allowed to know geological structures, and the characteristics of uranium mineralization. (M.C.F.) [pt

  7. Uranium mining in Australia

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    The mining of uranium in Australia is criticised in relation to it's environmental impact, economics and effects on mine workers and Aborigines. A brief report is given on each of the operating and proposed uranium mines in Australia

  8. Determination of colloidal and dissolved silver in water samples using colorimetric solid-phase extraction.

    Science.gov (United States)

    Hill, April A; Lipert, Robert J; Porter, Marc D

    2010-03-15

    The increase in bacterial resistance to antibiotics has led to resurgence in the use of silver as a biocidal agent in applications ranging from washing machine additives to the drinking water treatment system on the International Space Station (ISS). However, growing concerns about the possible toxicity of colloidal silver to bacteria, aquatic organisms and humans have led to recently issued regulations by the US EPA and FDA regarding the usage of silver. As part of an ongoing project, we have developed a rapid, simple method for determining total silver, both ionic (silver(I)) and colloidal, in 0.1-1mg/L aqueous samples, which spans the ISS potable water target of 0.3-0.5mg/L (total silver) and meets the US EPA limit of 0.1mg/L in drinking water. The method is based on colorimetric solid-phase extraction (C-SPE) and involves the extraction of silver(I) from water samples by passage through a solid-phase membrane impregnated with the colorimetric reagent DMABR (5-[4-(dimethylamino)benzylidene]rhodanine). Silver(I) exhaustively reacts with impregnated DMABR to form a colored compound, which is quantified using a handheld diffuse reflectance spectrophotometer. Total silver is determined by first passing the sample through a cartridge containing Oxone, which exhaustively oxidizes colloidal silver to dissolved silver(I). The method, which takes less than 2 min to complete and requires only approximately 1 mL of sample, has been validated through a series of tests, including a comparison with the ICP-MS analysis of a water sample from ISS that contained both silver(I) and colloidal silver. Potential earth-bound applications are also briefly discussed. Copyright (c) 2009 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

    Arsenault, J.E.

    2008-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Arsenault, J.E

    2008-03-15

    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

  11. Characterization and antibacterial properties of porous fibers containing silver ions

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Zhaoyang; Fan, Chenxu; Tang, Xiaopeng; Zhao, Jianghui; Song, Yanhua; Shao, Zhongbiao [National Engineering Laboratory for Modern Silk, College of Textile and Engineering, Soochow University, 199 Ren-ai Road, Suzhou 215123 (China); Xu, Lan, E-mail: lanxu@suda.edu.cn [National Engineering Laboratory for Modern Silk, College of Textile and Engineering, Soochow University, 199 Ren-ai Road, Suzhou 215123 (China); Nantong Textile Institute of Soochow University, 58 Chong-chuan Road, Nantong 226018 (China)

    2016-11-30

    Highlights: • Antibacterial electrospun PLA porous fibers containing silver ions were prepared. • Porous structure and porosity of PLA/Ag{sup +} porous fibers were investigated. • The antibacterial effects of PLA/Ag{sup +} porous fibers were studied. • The released mechanism of silver ions in the porous fibers was illustrated. • The porous structure could improve the antibacterial properties. - Abstract: Materials prepared on the base of bioactive silver compounds have become more and more popular. In the present work, the surface morphology, structure and properties, of electrospun Polylactide Polylactic acid (PLA) porous fibers containing various ratios of silver ions were investigated by a combination of X-ray photoelectron spectroscopy (XPS), universal testing machine, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and et al. The biological activities of the proposed porous fibers were discussed in view of the released silver ions concentration. Antibacterial properties of these porous fibers were studied using two bacterial strains: Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA). Results of the antibacterial testing suggested that PLA porous fibers containing silver ions could be used as potent antibacterial wound dressing materials in the biomedical field.

  12. Antibacterial effect of PEO coating with silver on AA7075

    Energy Technology Data Exchange (ETDEWEB)

    Cerchier, P., E-mail: pietrogiovanni.cerchier@studenti.unipd.it [Department of Industrial Engineering, University of Padua, Via Marzolo 9, 35131 Padova (Italy); Pezzato, L.; Brunelli, K. [Department of Industrial Engineering, University of Padua, Via Marzolo 9, 35131 Padova (Italy); Dolcet, P. [Department of Chemical Science, University of Padua, INSTM, UdR Padova and ICMATE-CNR, Padova (Italy); Bartolozzi, A.; Bertani, R.; Dabalà, M. [Department of Industrial Engineering, University of Padua, Via Marzolo 9, 35131 Padova (Italy)

    2017-06-01

    In this work, plasma electrolytic oxidation (PEO) coatings were produced on AA7075 using alkaline solution containing silicates compounds and silver micrometric particles in order to give to the coating an antimicrobial effect. In the optic of circular economy, silver chloride derived from the acid pre-treatment of electronic scraps was used as raw material and successively silver powders were synthesized from silver chloride solution using glucose syrup as reducing agent. The coatings were characterized by scanning electron microscope (SEM), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), potentiodynamic polarization test and antimicrobial tests. The results evidenced that the obtained coatings were homogenous and give to the samples higher corrosion resistance than untreated alloy. The silver particles, found both inside and outside of the pores that characterize the PEO layer, produced an efficacious antimicrobial effect both against E. coli and S. aureus. - Highlights: • Silver particles were incorporated into PEO coatings produced on aluminum alloys. • The incorporation was performed with direct addition of the particles in the electrolyte. • The particles resulted equally distributed on the samples surfaces. • The obtained coatings show antimicrobial activity with both E. coli and S. aureus. • The obtained coatings were characterized by acceptable corrosion resistance.

  13. Antibacterial effect of PEO coating with silver on AA7075

    International Nuclear Information System (INIS)

    Cerchier, P.; Pezzato, L.; Brunelli, K.; Dolcet, P.; Bartolozzi, A.; Bertani, R.; Dabalà, M.

    2017-01-01

    In this work, plasma electrolytic oxidation (PEO) coatings were produced on AA7075 using alkaline solution containing silicates compounds and silver micrometric particles in order to give to the coating an antimicrobial effect. In the optic of circular economy, silver chloride derived from the acid pre-treatment of electronic scraps was used as raw material and successively silver powders were synthesized from silver chloride solution using glucose syrup as reducing agent. The coatings were characterized by scanning electron microscope (SEM), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), potentiodynamic polarization test and antimicrobial tests. The results evidenced that the obtained coatings were homogenous and give to the samples higher corrosion resistance than untreated alloy. The silver particles, found both inside and outside of the pores that characterize the PEO layer, produced an efficacious antimicrobial effect both against E. coli and S. aureus. - Highlights: • Silver particles were incorporated into PEO coatings produced on aluminum alloys. • The incorporation was performed with direct addition of the particles in the electrolyte. • The particles resulted equally distributed on the samples surfaces. • The obtained coatings show antimicrobial activity with both E. coli and S. aureus. • The obtained coatings were characterized by acceptable corrosion resistance.

  14. Characterization and antibacterial properties of porous fibers containing silver ions

    International Nuclear Information System (INIS)

    Sun, Zhaoyang; Fan, Chenxu; Tang, Xiaopeng; Zhao, Jianghui; Song, Yanhua; Shao, Zhongbiao; Xu, Lan

    2016-01-01

    Highlights: • Antibacterial electrospun PLA porous fibers containing silver ions were prepared. • Porous structure and porosity of PLA/Ag + porous fibers were investigated. • The antibacterial effects of PLA/Ag + porous fibers were studied. • The released mechanism of silver ions in the porous fibers was illustrated. • The porous structure could improve the antibacterial properties. - Abstract: Materials prepared on the base of bioactive silver compounds have become more and more popular. In the present work, the surface morphology, structure and properties, of electrospun Polylactide Polylactic acid (PLA) porous fibers containing various ratios of silver ions were investigated by a combination of X-ray photoelectron spectroscopy (XPS), universal testing machine, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and et al. The biological activities of the proposed porous fibers were discussed in view of the released silver ions concentration. Antibacterial properties of these porous fibers were studied using two bacterial strains: Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA). Results of the antibacterial testing suggested that PLA porous fibers containing silver ions could be used as potent antibacterial wound dressing materials in the biomedical field.

  15. Uranium mining in Australia

    International Nuclear Information System (INIS)

    Mackay, G.A.

    1978-01-01

    Western world requirements for uranium based on increasing energy consumption and a changing energy mix, will warrant the development of Australia's resources. By 1985 Australian mines could be producing 9500 tonnes of uranium oxide yearly and by 1995 the export value from uranium could reach that from wool. In terms of benefit to the community the economic rewards are considerable but, in terms of providing energy to the world, Australias uranium is vital

  16. Radiation damage of uranium

    International Nuclear Information System (INIS)

    Lazarevic, Dj.

    1966-11-01

    Study of radiation damage covered the following: Kinetics of electric resistance of uranium and uranium alloy with 1% of molybdenum dependent on the second phase and burnup rate; Study of gas precipitation and diffusion of bubbles by transmission electron microscopy; Numerical analysis of the influence of defects distribution and concentration on the rare gas precipitation in uranium; study of thermal sedimentation of uranium alloy with molybdenum; diffusion of rare gas in metal by gas chromatography method

  17. Bicarbonate leaching of uranium

    International Nuclear Information System (INIS)

    Mason, C.

    1998-01-01

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

  18. Bicarbonate leaching of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Mason, C.

    1998-12-31

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

  19. Uranium in fossil bones

    International Nuclear Information System (INIS)

    Koul, S.L.

    1978-01-01

    An attempt has been made to determine the uranium content and thus the age of certain fossil bones Haritalyangarh (Himachal Pradesh), India. The results indicate that bones rich in apatite are also rich in uranium, and that the radioactivity is due to radionuclides in the uranium series. The larger animals apparently have a higher concentration of uranium than the small. The dating of a fossil jaw (elephant) places it in the Pleistocene. (Auth.)

  20. Chemical aspects of rubidium uranium sulphate for its use as a chemical standard for uranium

    International Nuclear Information System (INIS)

    Singh Mudher, K.D.; Khandekar, R.R.; Krishnan, K.; Jayadevan, N.C.; Sood, D.D.

    1989-01-01

    Rb 2 U(SO 4 ) 3 , a double sulphate of rubidium and uranium(IV) has been prepared and investigated for its use as a chemical standard for uranium. The compound can be easily prepared and crystallised in a pure form. The results of physico-chemical characterisation on preparation of 5-10 g. lots are described in this report. These studies suggest that the compound is anhydrous, stoichiometric, stable to atmospheric effects and easily soluble in acids and thus satisfies most of the criteria for a primary standard. (author). 13 refs., 4 figs., 6 tabs

  1. Method for converting uranium oxides to uranium metal

    International Nuclear Information System (INIS)

    Duerksen, W.K.

    1988-01-01

    A method for converting uranium oxide to uranium metal is described comprising the steps of heating uranium oxide in the presence of a reducing agent to a temperature sufficient to reduce the uranium oxide to uranium metal and form a heterogeneous mixture of a uranium metal product and oxide by-products, heating the mixture in a hydrogen atmosphere at a temperature sufficient to convert uranium metal in the mixture to uranium hydride, cooling the resulting uranium hydride-containing mixture to a temperature sufficient to produce a ferromagnetic transition in the uranium hydride, magnetically separating the cooled uranium hydride from the mixture, and thereafter heating the separated uranium hydride in an inert atmosphere to a temperature sufficient to convert the uranium hydride to uranium metal

  2. Microbial accumulation of uranium

    International Nuclear Information System (INIS)

    Zhang Wei; Dong Faqin; Dai Qunwei

    2005-01-01

    The mechanism of microbial accumulation of uranium and the effects of some factors (including pH, initial uranium concentration, pretreatment of bacteria, and so on) on microbial accumulation of uranium are discussed briefly. The research direction and application prospect are presented. (authors)

  3. Uranium energy dependence

    International Nuclear Information System (INIS)

    Erkes, P.

    1981-06-01

    Uranium supply and demand as projected by the Uranium Institute is discussed. It is concluded that for the industrialized countries, maximum energy independence is a necessity. Hence it is necessary to achieve assurance of supply for uranium used in thermal power reactors in current programs and eventually to move towards breeders

  4. Australian uranium today

    International Nuclear Information System (INIS)

    Fisk, B.

    1978-01-01

    The subject is covered in sections, entitled: Australia's resources; Northern Territory uranium in perspective; the government's decision [on August 25, 1977, that there should be further development of uranium under strictly controlled conditions]; Government legislation; outlook [for the Australian uranium mining industry]. (U.K.)

  5. Uranium resources, 1983

    International Nuclear Information System (INIS)

    1983-01-01

    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.)

  6. Recycling of reprocessed uranium

    International Nuclear Information System (INIS)

    Randl, R.P.

    1987-01-01

    Since nuclear power was first exploited in the Federal Republic of Germany, the philosophy underlying the strategy of the nuclear fuel cycle has been to make optimum use of the resource potential of recovered uranium and plutonium within a closed fuel cycle. Apart from the weighty argument of reprocessing being an important step in the treatment and disposal of radioactive wastes, permitting their optimum ecological conditioning after the reprocessing step and subsequent storage underground, another argument that, no doubt, carried weight was the possibility of reducing the demand of power plants for natural uranium. In recent years, strategies of recycling have emerged for reprocessed uranium. If that energy potential, too, is to be exploited by thermal recycling, it is appropriate to choose a slightly different method of recycling from the one for plutonium. While the first generation of reprocessed uranium fuel recycled in the reactor cuts down natural uranium requirement by some 15%, the recycling of a second generation of reprocessed, once more enriched uranium fuel helps only to save a further three per cent of natural uranium. Uranium of the second generation already carries uranium-232 isotope, causing production disturbances, and uranium-236 isotope, causing disturbances of the neutron balance in the reactor, in such amounts as to make further fabrication of uranium fuel elements inexpedient, even after mixing with natural uranium feed. (orig./UA) [de

  7. Trace metal assay of uranium silicide fuel

    International Nuclear Information System (INIS)

    Kulkarni, M.J.; Argekar, A.A.; Thulasidas, S.K.; Dhawale, B.A.; Rajeswari, B.; Adya, V.C.; Purohit, P.J.; Neelam, G.; Bangia, T.R.; Page, A.G.; Sastry, M.D.; Iyer, R.H.

    1994-01-01

    A comprehensive trace metal assay of uranium silicide, a fuel for nuclear research reactors that employs low-enrichment uranium, is carried out by atomic spectrometry. Of the list of specification elements, 21 metallic elements are determined by a direct current (dc) arc carrier distillation technique; the rare earths yttrium and zirconium are chemically separated from the major matrix followed by a dc arc/inductively coupled argon plasma (ICP) excitation technique in atomic emission spectrometry (AES); silver is determined by electrothermal atomization-atomic absorption spectrometry (ETA-AAS) without prior chemical separation of the major matrix. Gamma radioactive tracers are used to check the recovery of rare earths during the chemical separation procedure. The detection limits for trace metallics vary in the 0.1- to 40-ppm range. The precision of the determinations as evaluated from the analysis of the synthetic sample with intermediate range analyte concentration is better than 25% relative standard deviation (RSD) for most of the elements employing dc arc-AES, while that for silver determination by ETS-AAS is 10% RSD. The precision of the determinations for four crucially important rare earths by ICP-AES is better than 3% RSD

  8. Bibliographical study on photochemical separation of uranium isotopes

    International Nuclear Information System (INIS)

    Bougon, Roland

    1975-01-01

    The objective of this report is to propose an overview of knowledge and current works on isotopic separation of uranium by means of selective excitation where this excitation is obtained by a light source with a wave length corresponding to a selective or preferential absorption by a molecule or by the atom itself of one of the isotopes. After a brief overview of principles and requirements of isotopic separation by selective excitation, the author reviews compounds which can be used for this process. These compounds are mainly considered in terms of spectroscopy, and the study focuses on the most volatile among them, the uranium hexafluoride, its spectra, and possible processes for extraction. Some much less volatile uranium compounds are also mentioned with, when available, their spectroscopic properties. The uranium vapour excitation process is described, and some orientations for further researches are proposed [fr

  9. ATP7B detoxifies silver in ciliated airway epithelial cells

    International Nuclear Information System (INIS)

    Ibricevic, Aida; Brody, Steven L.; Youngs, Wiley J.; Cannon, Carolyn L.

    2010-01-01

    Silver is a centuries-old antibiotic agent currently used to treat infected burns. The sensitivity of a wide range of drug-resistant microorganisms to silver killing suggests that it may be useful for treating refractory lung infections. Toward this goal, we previously developed a methylated caffeine silver acetate compound, SCC1, that exhibits broad-spectrum antimicrobial activity against clinical strains of bacteria in vitro and when nebulized to lungs in mouse infection models. Preclinical testing of high concentrations of SCC1 in primary culture mouse tracheal epithelial cells (mTEC) showed selective ciliated cell death. Ciliated cell death was induced by both silver- and copper-containing compounds but not by the methylated caffeine portion of SCC1. We hypothesized that copper transporting P-type ATPases, ATP7A and ATP7B, play a role in silver detoxification in the airway. In mTEC, ATP7A was expressed in non-ciliated cells, whereas ATP7B was expressed only in ciliated cells. The exposure of mTEC to SCC1 induced the trafficking of ATP7B, but not ATP7A, suggesting the presence of a cell-specific silver uptake and detoxification mechanisms. Indeed, the expression of the copper uptake protein CTR1 was also restricted to ciliated cells. A role of ATP7B in silver detoxification was further substantiated when treatment of SCC1 significantly increased cell death in ATP7B shRNA-treated HepG2 cells. In addition, mTEC from ATP7B -/- mice showed enhanced loss of ciliated cells compared to wild type. These studies are the first to demonstrate a cell type-specific expression of the Ag + /Cu + transporters ATP7A, ATP7B, and CTR1 in airway epithelial cells and a role for ATP7B in detoxification of these metals in the lung.

  10. Antibacterial activity and toxicity of silver - nanosilver versus ionic silver

    International Nuclear Information System (INIS)

    Kvitek, L; Panacek, A; Prucek, R; Soukupova, J; Vanickova, M; Zboril, R; Kolar, M

    2011-01-01

    The in vitro study of antibacterial activity of silver nanoparticles (NPs), prepared via modified Tollens process, revealed high antibacterial activity even at very low concentrations around several units of mg/L. These concentrations are comparable with concentrations of ionic silver revealing same antibacterial effect. However, such low concentrations of silver NPs did not show acute cytotoxicity to mammalian cells - this occurs at concentrations higher than 60 mg/L of silver, while the cytotoxic level of ionic silver is much more lower (approx. 1 mg/L). Moreover, the silver NPs exhibit lower acute ecotoxicity against the eukaryotic organisms such as Paramecium caudatum, Monoraphidium sp. and D. melanogaster. The silver NPs are toxic to these organisms at the concentrations higher than 30 mg/L of silver. On contrary, ionic silver retains its cytoxicity and ecotoxicity even at the concentration equal to 1 mg/L. The performed experiments demonstrate significantly lower toxicity of silver NPs against the eukaryotic organisms than against the prokaryotic organisms.

  11. Antibacterial activity and toxicity of silver - nanosilver versus ionic silver

    Energy Technology Data Exchange (ETDEWEB)

    Kvitek, L; Panacek, A; Prucek, R; Soukupova, J; Vanickova, M; Zboril, R [Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University, 17. Listopadu 12, 77146 Olomouc (Czech Republic); Kolar, M, E-mail: ales.panacek@upol.cz [Department of Microbiology, Faculty of Medicine and Dentistry, Palacky University, Hnevotinska 3, 77520 Olomouc (Czech Republic)

    2011-07-06

    The in vitro study of antibacterial activity of silver nanoparticles (NPs), prepared via modified Tollens process, revealed high antibacterial activity even at very low concentrations around several units of mg/L. These concentrations are comparable with concentrations of ionic silver revealing same antibacterial effect. However, such low concentrations of silver NPs did not show acute cytotoxicity to mammalian cells - this occurs at concentrations higher than 60 mg/L of silver, while the cytotoxic level of ionic silver is much more lower (approx. 1 mg/L). Moreover, the silver NPs exhibit lower acute ecotoxicity against the eukaryotic organisms such as Paramecium caudatum, Monoraphidium sp. and D. melanogaster. The silver NPs are toxic to these organisms at the concentrations higher than 30 mg/L of silver. On contrary, ionic silver retains its cytoxicity and ecotoxicity even at the concentration equal to 1 mg/L. The performed experiments demonstrate significantly lower toxicity of silver NPs against the eukaryotic organisms than against the prokaryotic organisms.

  12. Comparison of silver release predictions using PARFUME with results from the AGR-2 irradiation experiment

    Energy Technology Data Exchange (ETDEWEB)

    Collin, Blaise P.; Demkowicz, Paul A.; Baldwin, Charles A.; Harp, Jason M.; Hunn, John D.

    2016-11-01

    The PARFUME (PARticle FUel ModEl) code was used to predict silver release from tristructural isotropic (TRISO) coated fuel particles and compacts during the second irradiation experiment (AGR-2) of the Advanced Gas Reactor Fuel Development and Qualification program. The PARFUME model for the AGR-2 experiment used the fuel compact volume average temperature for each of the 559 days of irradiation to calculate the release of fission product silver from a representative particle for a select number of AGR-2 compacts and individual fuel particles containing either mixed uranium carbide/oxide (UCO) or 100% uranium dioxide (UO2) kernels. Post-irradiation examination (PIE) measurements were performed to provide data on release of silver from these compacts and individual fuel particles. The available experimental fractional releases of silver were compared to their corresponding PARFUME predictions. Preliminary comparisons show that PARFUME under-predicts the PIE results in UCO compacts and is in reasonable agreement with experimental data for UO2 compacts. The accuracy of PARFUME predictions is impacted by the code limitations in the modeling of the temporal and spatial distributions of the temperature across the compacts. Nevertheless, the comparisons on silver release lie within the same order of magnitude.

  13. Silver release and antimicrobial properties of PMMA films doped with silver ions, nano-particles and complexes

    Energy Technology Data Exchange (ETDEWEB)

    Lyutakov, O., E-mail: lyutakoo@vscht.cz [Department of Solid State Engineering, Institute of Chemical Technology, Prague (Czech Republic); Goncharova, I. [Department of Analytical Chemistry, Institute of Chemical Technology, Prague (Czech Republic); Rimpelova, S. [Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague (Czech Republic); Kolarova, K.; Svanda, J.; Svorcik, V. [Department of Solid State Engineering, Institute of Chemical Technology, Prague (Czech Republic)

    2015-04-01

    Materials prepared on the base of bioactive silver compounds have become more and more popular due to low microbial resistance to silver. In the present work, the efficiency of polymethylmethacrylate (PMMA) thin films doped with silver ions, nanoparticles and silver–imidazole polymer complex was studied by a combination of AAS, XPS and AFM techniques. The biological activities of the proposed materials were discussed in view of the rate of silver releasing from the polymer matrix. Concentrations of Ag active form were estimated by its ability to interact with L-cysteine using electronic circular dichroism spectroscopy. Rates of the released silver were compared with the biological activity in dependence on the form of embedded silver. Antimicrobial properties of doped polymer films were studied using two bacterial strains: Staphylococcus epidermidis and Escherichia coli. It was found that PMMA films doped with Ag{sup +} had greater activity than those doped with nanoparticles and silver–imidazole polymeric complexes. However, the antimicrobial efficiency of Ag{sup +} doped films was only short-term. Contrary, the antimicrobial activity of silver–imidazole/PMMA films increased in time of sample soaking. - Highlights: • PMMA thin films doped with silver ions, nanoparticles (AgNPs) and silver–imidazole helical complexes (AgIm) were studied. • Silver release from doped polymer films and its biological activity were estimated. • Antimicrobial properties of doped polymer films were also studied. • Ag ions doped films showed the strongest antimicrobial activity, which quickly disappeared. • AgIm and AgNPs doped films showed more stable antimicrobial properties. • AgIm complexes conserve their structure after addition into polymer and after leaching.

  14. Silver release and antimicrobial properties of PMMA films doped with silver ions, nano-particles and complexes

    International Nuclear Information System (INIS)

    Lyutakov, O.; Goncharova, I.; Rimpelova, S.; Kolarova, K.; Svanda, J.; Svorcik, V.

    2015-01-01

    Materials prepared on the base of bioactive silver compounds have become more and more popular due to low microbial resistance to silver. In the present work, the efficiency of polymethylmethacrylate (PMMA) thin films doped with silver ions, nanoparticles and silver–imidazole polymer complex was studied by a combination of AAS, XPS and AFM techniques. The biological activities of the proposed materials were discussed in view of the rate of silver releasing from the polymer matrix. Concentrations of Ag active form were estimated by its ability to interact with L-cysteine using electronic circular dichroism spectroscopy. Rates of the released silver were compared with the biological activity in dependence on the form of embedded silver. Antimicrobial properties of doped polymer films were studied using two bacterial strains: Staphylococcus epidermidis and Escherichia coli. It was found that PMMA films doped with Ag + had greater activity than those doped with nanoparticles and silver–imidazole polymeric complexes. However, the antimicrobial efficiency of Ag + doped films was only short-term. Contrary, the antimicrobial activity of silver–imidazole/PMMA films increased in time of sample soaking. - Highlights: • PMMA thin films doped with silver ions, nanoparticles (AgNPs) and silver–imidazole helical complexes (AgIm) were studied. • Silver release from doped polymer films and its biological activity were estimated. • Antimicrobial properties of doped polymer films were also studied. • Ag ions doped films showed the strongest antimicrobial activity, which quickly disappeared. • AgIm and AgNPs doped films showed more stable antimicrobial properties. • AgIm complexes conserve their structure after addition into polymer and after leaching

  15. PROCESS OF RECOVERING URANIUM

    Science.gov (United States)

    Carter, J.M.; Larson, C.E.

    1958-10-01

    A process is presented for recovering uranium values from calutron deposits. The process consists in treating such deposits to produce an oxidlzed acidic solution containing uranium together with the following imparities: Cu, Fe, Cr, Ni, Mn, Zn. The uranium is recovered from such an impurity-bearing solution by adjusting the pH of the solution to the range 1.5 to 3.0 and then treating the solution with hydrogen peroxide. This results in the precipitation of uranium peroxide which is substantially free of the metal impurities in the solution. The peroxide precipitate is then separated from the solution, washed, and calcined to produce uranium trioxide.

  16. Characterization of Electrochemically Generated Silver

    Science.gov (United States)

    Adam, Niklas; Martinez, James; Carrier, Chris

    2014-01-01

    Silver biocide offers a potential advantage over iodine, the current state of the art in US spacecraft disinfection technology, in that silver can be safely consumed by the crew. Low concentrations of silver (Silver does not require hardware to remove it from a water system, and therefore can provide a simpler means for disinfecting water. The Russian segment of the International Space Station has utilized an electrochemically generated silver solution, which is colloidal in nature. To be able to reliably provide a silver biocide to drinking water by electrochemical means would reduce mass required for removing another biocide such as iodine from the water. This would also aid in crew time required to replace iodine removal cartridges. Future long term missions would benefit from electrochemically produced silver as the biocide could be produced on demand and requires only a small concentration to be effective. Since it can also be consumed safely, there is less mass in removal hardware and little consumables required for production. The goal of this project initially is to understand the nature of the electrochemically produced silver, the particle sizes produced by the electrochemical cell and the effect that voltage adjustment has on the particle size. In literature, it has been documented that dissolved oxygen and pH have an effect on the ionization of the electrochemical silver so those parameters would be measured and possibly adjusted to understand their effect on the silver.

  17. Fluorinated compounds in the uranium conversion process: risk analysis and proposition of pictograms; Os compostos fluorados nos processos da conversao do uranio: analise de riscos e proposicao de pictogramas

    Energy Technology Data Exchange (ETDEWEB)

    Jeronimo, Adroaldo Clovis; Oliveira, Wagner dos Santos, E-mail: acejota18@yahoo.com.br, E-mail: oliveira@feq.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Quimica; Aquino, Afonso Rodrigues de, E-mail: araquino@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-03-15

    In the process of uranium hexafluoride production there are risks that must be taken into account since the time of completing the project chemist, in its conceptual stage, until to the stage of detailed design and are associated with the handling of chemicals, especially fluoride hydrogen and fluorine. This paper aims to address issues related to the prevention of risks related to industrial safety and health and the environment, considering the different stages of the uranium conversion. Take into account the safety warnings of the plant and, accordingly, make the proposition of pictograms adequate to alert operators of care to be taken during the proposition of pictograms adequate to alert operators of care to be taken during the conduct of these chemical processes. (author)

  18. Method for converting uranium oxides to uranium metal

    Science.gov (United States)

    Duerksen, Walter K.

    1988-01-01

    A process is described for converting scrap and waste uranium oxide to uranium metal. The uranium oxide is sequentially reduced with a suitable reducing agent to a mixture of uranium metal and oxide products. The uranium metal is then converted to uranium hydride and the uranium hydride-containing mixture is then cooled to a temperature less than -100.degree. C. in an inert liquid which renders the uranium hydride ferromagnetic. The uranium hydride is then magnetically separated from the cooled mixture. The separated uranium hydride is readily converted to uranium metal by heating in an inert atmosphere. This process is environmentally acceptable and eliminates the use of hydrogen fluoride as well as the explosive conditions encountered in the previously employed bomb-reduction processes utilized for converting uranium oxides to uranium metal.

  19. Uranium speciation in plants

    International Nuclear Information System (INIS)

    Guenther, A.; Bernhard, G.; Geipel, G.; Reich, T.; Rossberg, A.; Nitsche, H.

    2003-01-01

    Detailed knowledge of the nature of uranium complexes formed after the uptake by plants is an essential prerequisite to describe the migration behavior of uranium in the environment. This study focuses on the determination of uranium speciation after uptake of uranium by lupine plants. For the first time, time-resolved laser-induced fluorescence spectroscopy and X-ray absorption spectroscopy were used to determine the chemical speciation of uranium in plants. Differences were detected between the uranium speciation in the initial solution (hydroponic solution and pore water of soil) and inside the lupine plants. The oxidation state of uranium did not change and remained hexavalent after it was taken up by the lupine plants. The chemical speciation of uranium was identical in the roots, shoot axis, and leaves and was independent of the uranium speciation in the uptake solution. The results indicate that the uranium is predominantly bound as uranyl(VI) phosphate to the phosphoryl groups. Dandelions and lamb's lettuce showed uranium speciation identical to lupine plants. (orig.)

  20. Kazakhstan uranium industry: towards the XXI century with clean technologies

    International Nuclear Information System (INIS)

    Dzhakishev, M.E.; Yazikov, V.G.; Dujsebaev, B.O.; Zabaznov, V.L.

    2001-01-01

    Kazakhstan is a leading country of the world by uranium resources, and in the it Earth's interior 19 % of world proved resources are concentrated. At present the National Atomic Company (NAC) Kazatomprom is responsible for uranium mining and production of natural uranium and its compounds in the Republic. The company activity covers the exploring, mining and export of natural uranium; production of slightly enriched uranium compounds and fuel pellets production for nuclear reactors. In the company there are three Uranium Ore Mining Departments in the South Kazakhstan, VolgovGeology Geological Exploration Enterprise and Ulba Metallurgical Plant. Mining is carrying out by technologically progressive ecologically clean technology of in-situ well leaching. The key importance the company pays to environment protection activities. NAC Kazatomprom sees perspectives of Kazakhstan uranium industry in formation of general all-sufficient technological cycle from uranium mining to fuel supply on the nuclear plants. The missing links - enrichment by U-235 isotope and fuel assemblies production - should be replaces by formation of steady partnership cooperation with foreign enterprises

  1. Uranium mill decommissioning - an update on the Edgemont experience

    International Nuclear Information System (INIS)

    Donovan, Th.K.; Chart, E.J.; Cummings, G.W.; Tappan, J.T.

    1983-01-01

    This paper describes the Edgemont Uranium Mill Decommissioning Project. An estimated 5.4 million tons of contaminated material including approximately 2.5 million tons of uranium mill tailings will be moved to a disposal site approved by the Nuclear Regulatory Commission (NRC). The decommissioning activities will be carried out by Silver King Mines, Inc., under a management services contract to the Tennessee Valley Authority. The primary advantages of the disposal site chosen are the short distance from the existing site and the approximately 650 feet of relatively dense impermeable shales above the shallowest known aquifer. Three large ore stockpiles containing about 100,000 pounds of uranium have been moved from the mill site to a proposed mine site. The decommissioning project will be carried out by using the existing labor force to the maximum extent possible thus preventing a population influx and the accompanying socioeconomic input to the city of Edgemont, SD

  2. Estimation of metallic impurities in uranium by carrier distillation method

    International Nuclear Information System (INIS)

    Page, A.G.; Godbole, S.V.; Deshkar, S.B.; Joshi, B.D.

    1976-01-01

    An emission spectrographic method has been standardised for the estimation of twenty-two metallic impurities in uranium using carrier-distillation technique. Silver chloride with a concentration of 5% has been used as the carrier and palladium and gallium are used as internal standards. Precision and accuracy determinations of the synthetic samples indicate 6-15% deviation for most of the elements. Using the method described here, five uranium reference samples received from C.E.A.-France were analysed. The detection limits obtained for Cd, Co and W are lower than those reported in the literature while limits for the remaining elements are comparable to the values reported. The method is suitable for the chemical quality control analysis of uranium used for the Fast Breeder Test Reactor (FBTR) fuel. (author)

  3. Silver matrix composites reinforced with galvanically silvered particles

    OpenAIRE

    J. Śleziona; J. Wieczorek,

    2007-01-01

    Purpose: The paper presents the possibility of the application of metalic layers drifted with the use of the galvanic methods on the ceramic particles surface. The application of the layers was aimed at obtaining the rewetting of the reinforcing particles with the liquid silver in the course of the producing of silver matrix composites with the use of mechanical stirring method. To enable introducing of the iron powder and glass carbon powder to liquid silver the solution of covering the powd...

  4. Morphological study of silver corrosion in highly aggressive sulfur environments

    DEFF Research Database (Denmark)

    Minzari, Daniel; Jellesen, Morten Stendahl; Møller, Per

    2011-01-01

    A silicone coated power module, having silver conducting lines, showed severe corrosion, after prolonged use as part of an electronic device in a pig farm environment, where sulfur containing corrosive gasses are known to exist in high amounts. Permeation of sulfur gasses and humidity through...... the silicone coating to the interface has resulted in three corrosion types namely: uniform corrosion, conductive anodic filament type of Ag2S growth, and silver migration with subsequent formation of sulfur compounds. Detailed morphological investigation of new and corroded power modules was carried out...

  5. 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. The...

  6. Analysis on uranium metallogenetic conditions of granite pluton in Ulan Uzhur

    International Nuclear Information System (INIS)

    Lu Yaozu

    2014-01-01

    Qimantage area in Qinghai province is one of the important exploration areas in the present China, Ulan Uzhur complex pluton, located in the compound tectonic magmatic belt of Qimantage, is the main cluster area with uranium mineralization. This paper describes the petrochemical, geochemical, petrophysical and Heishan uranium deposit mineralization characteristics of rocks formed at the different tectonic-magmatic cycles in Ulan Uzhur complex pluton. Uranium metallogenic conditions in Ulan Uzhur complex pluton were analyzed from uranium source, magmatic activity and structure. The research shew that the Ulan Uzhur complex pluton has the petrochemical characteristics of uranium rock and Cisuralian monzonitic granite has the most significant relationship to uranium mineralization, it has the characteristics of high background radiation, many anomalies and pronounced ore-control structure, Heishan uranium deposit was controlled by factors such as pronounced northeast and the northwest structure and alteration. To conclude, Ulan Uzhur complex pluton possesses good uranium metallogenic prospect. (author)

  7. Risk assessment applications for determining cleanup limits for uranium in treated and untreated soils

    International Nuclear Information System (INIS)

    Armstrong, A.Q.; Layton, D.W.; Rutz, E.E.

    1994-01-01

    Uranium-contaminated soils are present at various locations across the US where uranium was processed for nuclear fuels or atomic weapons. Important issues relative to such contamination include the assessment of potential health risks associated with human exposures to the residual uranium and the determination of safe levels of uranium in soils that have been treated by a given technology. This paper discusses various risk assessment considerations that must be dealt with when developing cleanup limits for uranium in treated and untreated soils. Key issues addressed include alternative land use scenarios, potential exposure pathways, characterization of the bioavailability of uranium compounds in food and water, a brief overview of health risks associated with uranium and its daughter products as well as a summary of considerations for development of risk-based cleanup limits for uranium in soils

  8. Spectrographic determination of microconstituents in uranium tetrafluoride

    International Nuclear Information System (INIS)

    Paula Reino, L.C. de; Lordello, A.R.

    1982-11-01

    A espectrographic method for the direct determination of impurities in uranium tetrafluoride (UF 4 ) was developed. The major impurities introduced during the preparation of UF 4 (Fe, Ni, Cr) and other impurities introduced in the prior stages of this preparation were determined. Spectrochemical carriers were used to suppress the uranium distillation during excitation, because fluoride compound is more volatile the refractory matrix (U 3 O 8 ). Better results were obtained using as carrier a mixture of 20% MgO and 10% MgO and 10% NaCl, concerning to the UF 4 matrix. The sensibilities for some of those impurities are in the ppm level. (Author) [pt

  9. Chemical interactions between the metallic silver aerosols and the iodide compounds in the containment building of a PWR reactor during a serious accident; Interactions chimiques entre les aerosols d'argent metallique et les composes iodes dans l'enceinte de confinement d'un reacteur nucleaire a eau pressurisee en cas d'accident grave

    Energy Technology Data Exchange (ETDEWEB)

    Serra, D.; Saint-Raymond, O.; Zoulalian, A. [Universite Henri Poincare, LERMAB-ENSTIB, 54 - Vandoeuvre-les-Nancy (France); Montanelli, T. [CEA/Cadarache, Inst. de Protection et de Surete Nucleaire, IPSN/DRS/SESHP/LEATS, 13 - Saint-Paul-lez-Durance (France)

    2000-07-01

    During an hypothetical severe accident in a PWR, the iodide fission products can be transferred into the liquid phase of the containment with silver particles (or silver colloid) resulting from the fusion and the vaporization of neutronic control rods. The chemical interactions between the iodide ions and the molecular iodine with the silver particles are studied in an aqueous phase separately and without radiation. The interaction between the iodide ions and silver particles requires a preliminary oxidation step of the silver particles the rate of which depends on the pH, the temperature and the liquid oxygen concentration. A kinetic model including two independent stoichiometries allows to represent correctly the whole experimental runs. At pH = 3, the chemical interactions between molecular iodine and silver particles do not require an oxidation step and a second order kinetic model is able to represent the experimental results considering the operating conditions studied. (authors)

  10. Nucleic acid nanomaterials: Silver-wired DNA

    Science.gov (United States)

    Auffinger, Pascal; Ennifar, Eric

    2017-10-01

    DNA double helical structures are supramolecular assemblies that are typically held together by classical Watson-Crick pairing. Now, nucleotide chelation of silver ions supports an extended silver-DNA hybrid duplex featuring an uninterrupted silver array.

  11. Genetics Home Reference: Russell-Silver syndrome

    Science.gov (United States)

    ... Other Names for This Condition RSS Silver-Russell dwarfism Silver-Russell syndrome SRS Related Information How are ... M, Begemann M, Elbracht M. Epigenetic and genetic diagnosis of Silver-Russell syndrome. Expert Rev Mol Diagn. ...

  12. Silver against Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Kirketerp-Møller, K.; Kristiansen, S.

    2007-01-01

    bacteria in both the planktonic and biofilm modes of growth. The action of silver on mature in vitro biofilms of Pseudomonas aeruginosa, a primary pathogen of chronic infected wounds, was investigated. The results show that silver is very effective against mature biofilms of P. aeruginosa......, but that the silver concentration is important. A concentration of 5-10 ig/mL silver sulfadiazine eradicated the biofilm whereas a lower concentration (1 ig/mL) had no effect. The bactericidal concentration of silver required to eradicate the bacterial biofilm was 10-100 times higher than that used to eradicate...... planktonic bacteria. These observations strongly indicate that the concentration of silver in currently available wound dressings is much too low for treatment of chronic biofilm wounds. It is suggested that clinicians and manufacturers of the said wound dressings consider whether they are treating wounds...

  13. Silver nanoparticles and silver nitrate induce high toxicity to Pseudokirchneriella subcapitata, Daphnia magna and Danio rerio

    International Nuclear Information System (INIS)

    Ribeiro, Fabianne; Gallego-Urrea, Julián Alberto; Jurkschat, Kerstin; Crossley, Alison; Hassellöv, Martin; Taylor, Cameron; Soares, Amadeu M.V.M.; Loureiro, Susana

    2014-01-01

    Silver nanoparticles (AgNP) have gained attention over the years due to the antimicrobial function of silver, which has been exploited industrially to produce consumer goods that vary in type and application. Undoubtedly the increase of production and consumption of these silver-containing products will lead to the entry of silver compounds into the environment. In this study we have used Pseudokirchneriella subcapitata, Daphnia magna and Danio rerio as model organisms to investigate the toxicity of AgNP and AgNO 3 by assessing different biological endpoints and exposure periods. Organisms were exposed following specific and standardized protocols for each species/endpoints, with modifications when necessary. AgNP were characterized in each test-media by Transmission Electron Microscopy (TEM) and experiments were performed by Dynamic Light Scattering (DLS) to investigate the aggregation and agglomeration behavior of AgNP under different media chemical composition and test-period. TEM images of AgNP in the different test-media showed dissimilar patterns of agglomeration, with some agglomerates inside an organic layer, some loosely associated particles and also the presence of some individual particles. The toxicity of both AgNO 3 and AgNP differ significantly based on the test species: we found no differences in toxicity for algae, a small difference for zebrafish and a major difference in toxicity for Daphnia magna. - Highlights: •Effects of silver nanoparticles and nitrate were compared in three aquatic species. •The presence of food on the immobilization assay for Daphnia magna significantly decreased AgNP toxicity. •AgNP and AgNO 3 differ in toxicity according to the test species and endpoint. •AgNP and AgNO 3 induced dissimilar abnormalities on zebrafish embryos' development. •AgNP behavior in the test media will rule its bioavailability and uptake and therefore toxicity

  14. Silver nanoparticles and silver nitrate induce high toxicity to Pseudokirchneriella subcapitata, Daphnia magna and Danio rerio

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Fabianne, E-mail: ribeiro.f@ua.pt [Department of Biology and CESAM, University of Aveiro. Campus Universitario de Santiago, 3810-193. Aveiro (Portugal); Gallego-Urrea, Julián Alberto [Department of Chemistry and Molecular Biologyx, University of Gothenburg, Kemivägen 4, 41296 Gothenburg (Sweden); Jurkschat, Kerstin; Crossley, Alison [Department of Materials, Oxford University Begbroke Science Park OX5 1PF (United Kingdom); Hassellöv, Martin [Department of Chemistry and Molecular Biologyx, University of Gothenburg, Kemivägen 4, 41296 Gothenburg (Sweden); Taylor, Cameron [Department of Materials, Oxford University Begbroke Science Park OX5 1PF (United Kingdom); Soares, Amadeu M.V.M.; Loureiro, Susana [Department of Biology and CESAM, University of Aveiro. Campus Universitario de Santiago, 3810-193. Aveiro (Portugal)

    2014-01-01

    Silver nanoparticles (AgNP) have gained attention over the years due to the antimicrobial function of silver, which has been exploited industrially to produce consumer goods that vary in type and application. Undoubtedly the increase of production and consumption of these silver-containing products will lead to the entry of silver compounds into the environment. In this study we have used Pseudokirchneriella subcapitata, Daphnia magna and Danio rerio as model organisms to investigate the toxicity of AgNP and AgNO{sub 3} by assessing different biological endpoints and exposure periods. Organisms were exposed following specific and standardized protocols for each species/endpoints, with modifications when necessary. AgNP were characterized in each test-media by Transmission Electron Microscopy (TEM) and experiments were performed by Dynamic Light Scattering (DLS) to investigate the aggregation and agglomeration behavior of AgNP under different media chemical composition and test-period. TEM images of AgNP in the different test-media showed dissimilar patterns of agglomeration, with some agglomerates inside an organic layer, some loosely associated particles and also the presence of some individual particles. The toxicity of both AgNO{sub 3} and AgNP differ significantly based on the test species: we found no differences in toxicity for algae, a small difference for zebrafish and a major difference in toxicity for Daphnia magna. - Highlights: •Effects of silver nanoparticles and nitrate were compared in three aquatic species. •The presence of food on the immobilization assay for Daphnia magna significantly decreased AgNP toxicity. •AgNP and AgNO{sub 3} differ in toxicity according to the test species and endpoint. •AgNP and AgNO{sub 3} induced dissimilar abnormalities on zebrafish embryos' development. •AgNP behavior in the test media will rule its bioavailability and uptake and therefore toxicity.

  15. Analysis of prospecting effect of polonium survey and geoelectric survey extracted uranium and molybdenum in the south of Shengyuan volcanic basin

    International Nuclear Information System (INIS)

    Jin Hehai

    2007-01-01

    Polonium survey and geoelectric survey extracted uranium and molybdenum show that compound anomaly with sharp anomaly peak of the curve of polonium-210, uranium, molybdenum appears along many survey lines in Bakou area, Shengyuan volcanic basin, which may reflect the enrichment of uranium and molybdenum in rock formation and soil layer. By contrasting the anomaly curve to that above the buried uranium deposit, it is recognized that compound anomaly is closely related to the uranium mineralization condition in the area and some favourable sites for uranium metallogeny have been predicated. (authors)

  16. Uranium distribution and fixation in main types of climatic and stational pedogenesis on crystalline rocks

    International Nuclear Information System (INIS)

    Gueniot, B.

    1983-11-01

    An experimental and analytical study of uranium behavior in soils and of its distribution was carried out for bioclimatic pedogenesis on crystalline rocks, generally granites. Uranium distribution, and sometimes thorium) is compared to the distribution of tracers of pedogenesis (C, Fe, Al, Si, alkalis, clays). Uranium and thorium behavior is dependent of pedogenesis and can be leached or concentrated. Various fractions of soil alteration complexes and associated uranium can be isolated by chemical and physical fractionation and fixation sites for U are evidenced, efficiency is tested in situ. Adsorption is low onclays, fixation is frequent on oxyhydroxides, organic compounds are active for uranium complexation [fr

  17. Gilded Silver Mask

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    This gilded silver mask from the Liao Dynasty is 31 cm long and 22.2 cm wide. The plump oval face was designed with a protruding brow ridge, narrow eyes, high-bridged nose and closed mouth. The chin is slightly round against a thin neck, the ears are long and the hair can be clearly seen from the finely carved lines. The use of masks was recorded as

  18. Biological synthesis of silver nanoparticles

    International Nuclear Information System (INIS)

    Maliszewska, I; Szewczyk, K; Waszak, K

    2009-01-01

    Fungus-mediated synthesis of silver nanoparticles is reported. The nanosilver was formed in contact with the cell-free filtrate of Penicillium strain studied. The nanoparticles were characterized by means of the UV-Vis spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The synthesized nanosilver showed a absorbed maximum at 425 nm in the visible region. The SEM characterization of the fungus cells treated with silver nitrite indicated that the protein might be responsible for the reduction of silver ions. Transmission electron microscopy (TEM) micrograph showed formation of silver nanoparticles in the range of 10-100 nm.

  19. Silver precipitation from electrolytic effluents

    International Nuclear Information System (INIS)

    Rivera, I.; Patino, F.; Cruells, M.; Roca, A.; Vinals, J.

    2004-01-01

    The recovery of silver contained in electrolytic effluents is attractive due to its high economic value. These effluents are considered toxic wastes and it is not possible to dump them directly without any detoxification process. One of the most important way for silver recovery is the precipitation with sodium ditionite, sodium borohidride or hydrazine monohidrate. In this work, the most significant aspects related to the use of these reagents is presented. Results of silver precipitation with sodium ditionite from effluents containing thiosulfate without previous elimination of other species are also presented. silver concentration in the final effluents w <1 ppm. (Author) 15 refs

  20. Uranium of Kazakhstan

    International Nuclear Information System (INIS)

    Tsalyuk, Yu.; Gurevich, D.

    2000-01-01

    Over 25 % of the world's uranium reserves are concentrated in Kazakhstan. So, the world's largest Shu-Sarysu uranium province is situated on southern Kazakhstan, with resources exceeding 1 billion tonnes of uranium. No less, than 3 unique deposits with resources exceeding 100,000 tonnes are situated here. From the economic point of view the most important thing is that these deposits are suitable for in-situ leaching, which is the cheapest, environmentally friendly and most efficient method available for uranium extracting. In 1997 the Kazatomprom National Joint-Stock Company united all Kazakhstan's uranium enterprises (3 mine and concentrating plants, Volkovgeologiya Joint-Stock Company and the Ulbinskij Metallurgical plant). In 1998 uranium production came to 1,500 tonnes (860 kg in 1997). In 1999 investment to the industry were about $ 30 million. Plans for development of Kazakhstan's uranium industry provide a significant role for foreign partners. At present, 2 large companies (Comeco (Canada), Cogema (France) working in Kazakhstan. Kazakatomprom continues to attract foreign investors. The company's administration announced that in that in next year they have plan to make a radical step: to sell 67 % of stocks to strategic investors (at present 100 % of stocks belongs to state). Authors of the article regard, that the Kazakhstan's uranium industry still has significant reserves to develop. Even if the scenario for the uranium industry could be unfavorable, uranium production in Kazakhstan may triple within the next three to four years. The processing of uranium by the Ulbinskij Metallurgical Plant and the production of some by-products, such as rhenium, vanadium and rare-earth elements, may provide more profits. Obviously, the sale of uranium (as well as of any other reserves) cannot make Kazakhstan a prosperous country. However, country's uranium industry has a god chance to become one of the most important and advanced sectors of national economy

  1. Method of converting uranium fluoride to intermediate product for uranium oxide manufacture with recycling or reusing valuable materials

    International Nuclear Information System (INIS)

    Baran, V.; Moltasova, J.

    1982-01-01

    Uranium fluoride is acted upon by water with nitrate containing a cation capable of binding fluoride ions. The uranium is extracted, for instance, with tributyl phosphate with the generated organic phase containing the prevalent proportion of uranium and representing the required intermediate product and the aqueous phase from which is isolated the fluorine component which may be used within the fuel cycle. The nitrate component of the aqueous phase is recycled following treatment. It is also possible to act on uranium fluoride directly with an aqueous solution. Here the cations of nitrate form with the fluorides soluble nondissociated complexes and reduce the concentration of free fluoride ions. The nitrate +s mostly used in an amount corresponding to its solubility in the system prior to the introduction of UF 6 . The uranium from the solution with the reduced concentration of free fluoride ions is extracted into the reaction system under such conditions as to make the prevalent majority of fluorides and an amount of uranium smaller than 5x10 -2 mol/l remain in the aqueous phase and that such an amount of fluorides should remain in the organic phase which is smaller than corresponds to the fluorine/uranium molar ratio in the organic phase. Uranium contained in the organic phase is processed into uranium oxide, with advantage into UO 2 . From the isolated compounds of fluorine and the cation of the nitrate gaseous HF is released which is used either inside or outside of the fuel cycle. (J.P.)

  2. Spectrographic determination of boron and silicon in uranium tetrafluoride: Study of the chemical reactions in the electrode cavity when ZnO is used as a uranium excitation suppressor

    International Nuclear Information System (INIS)

    Alduan, F. A.; Capdevila, C.; Roca, M.

    1973-01-01

    A method has been developed for determining traces of boron and silicon in uranium tetrafluoride. Use is made of zinc oxide to decrease the volatilization of uranium and achieve high sensitivities. The thermochemical reactions which occur in the anode cavity during the arcing process have been investigated. UO 2 and a uranium, zinc and fluorine compound, both less volatile than uranium tetrafluoride, are formed. (Author)

  3. Studies on ternary silver sulfides; Fukugo gin ryukabutsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-31

    Some sulfides containing silver show high ion mobility based on movability of silver, whose application is expected. Studies have been carried out centrally on synthesis of new compounds of ternary silver sulfides by elucidating the relationship among their compositions, structures and properties by means of crystal chemical studies mainly on their phase relationship. A few new compounds have been synthesized, such as the ones having the argyrodite family compound structure including transition metals. The synthesizing process takes a kind of turbulent liquid state structure at elevated temperatures because of movability of silver, but silver is fixed at low temperatures in different sites between skeleton structures made by other atoms. These studies on phase transfer, structures, and silver movability have been based on X-ray diffraction, infrared and Raman spectroscopic measurements, NMR, measurements of electric and thermal characteristics. For the studies related to compositions and structures of ternary metal sulfides which take compound crystalline structure, a structure analyzing method based on multi-dimensional hyperspatial groups was used. This paper reports the summary of the studies in seven chapters, and dwells on the remaining problems and future prospects. 158 refs., 114 figs., 65 tabs.

  4. Green Synthesis of Silver Nanoparticles from several NTFP Plants

    Directory of Open Access Journals (Sweden)

    Somnath BHOWMIK

    2016-03-01

    Full Text Available The biological synthesis of nanoparticles using plant extracts plays an important role in the field of nanotechnology. In this study, rapid, simple approach was applied for synthesis of silver nanoparticles using , Clerodendrum infortunatum, Mucuna interrupta, Phlogancanthus thyrsiflorus and Sansevieria trifasciata aqueous leaf extract. The plant extract acts both as reducing agent as well as capping agent. To identify the compounds responsible for reduction of silver ions, the functional groups present in plant extract were investigated by FTIR. Various techniques used to characterize synthesized nanoparticles are Scanning Electron Microscopy (SEM, Atomic Force Microscopy (AFM and UV–Visible spectrophotometer. Results confirmed that this protocol was simple, rapid, one step, eco-friendly, non-toxic and might be an alternative conventional physical/chemical methods. Conversion of silver nanoparticles takes place at room temperature without the involvement of any hazardous chemicals.

  5. Graphene coatings for chemotherapy: avoiding silver-mediated degradation

    International Nuclear Information System (INIS)

    Mazzola, Federico; Cooil, Simon; Skjønsfjell, Eirik Torbjørn Bakken; Breiby, Dag W; Wells, Justin W; Trinh, Thuat; Kjelstrup, Signe; Østli, Elise Ramleth; Høydalsvik, Kristin; Preobrajenski, Alexei; Cafolla, Attilio A; Evans, D Andrew

    2015-01-01

    Chemotherapy treatment usually involves the delivery of fluorouracil (5-Fu) together with other drugs through central venous catheters. Catheters and their connectors are increasingly treated with silver or argentic alloys/compounds. Complications arising from broken catheters are common, leading to additional suffering for patients and increased medical costs. Here, we uncover a likely cause of such failure through a study of the surface chemistry relevant to chemotherapy drug delivery, i.e. between 5-Fu and silver. We show that silver catalytically decomposes 5-Fu, compromising the efficacy of the chemotherapy treatment. Furthermore, HF is released as a product, which will be damaging to both patient and catheter. We demonstrate that graphene surfaces inhibit this undesirable reaction and would offer superior performance as nanoscale coatings in cancer treatment applications. (paper)

  6. Efficient synthesis of silver nanoparticles from Prosopis juliflora leaf extract and its antimicrobial activity using sewage.

    Science.gov (United States)

    Raja, K; Saravanakumar, A; Vijayakumar, R

    2012-11-01

    In this paper, aqueous extract of fresh leaves of Prosopis juliflora was used for the synthesis of silver (Ag) nanoparticles. UV-Vis spectroscopy studies were carried out to asses silver nanoparticles formation within 5 min, scanning electron microscopic was used to characterize shape of the Ag nanoparticles, X-ray diffraction analysis confirms the nanoparticles as crystalline silver and facecentered cubic type and Fourier transform infra-red assed that shows biomolecule compounds which are responsible for reduction and capping material of silver nanoparticles. The anti microbial activity of silver nanoparticle was performed using sewage. The approach of plant-mediated synthesis appears to be cost efficient, eco-friendly and easy methods. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. CO2 laser direct writing of silver lines on epoxy resin from solid film

    International Nuclear Information System (INIS)

    Liu, J.G.; Chen, C.H.; Zheng, J.S.; Huang, J.Y.

    2005-01-01

    A technique of CO 2 laser direct writing from solid film was proposed in this paper. Patterns of silver lines were locally deposited on the non-conductive substrate using a preset layer of silver compound solid film, which was irradiated by focused CO 2 laser beam. The deposits were analyzed by XPS and EPMA. Results showed that metallic silver was dominant with an even distribution on the surface of the substrate, and part of the deposited silver had diffused into the substrate interior. The deposits had catalytic activity for the further electroless copper plating and had strong adhesion to the substrate. At last, the deposition mechanism and the dependence of the width of silver lines on the laser power and scan speed were roughly explored

  8. Efficient synthesis of silver nanoparticles from Prosopis juliflora leaf extract and its antimicrobial activity using sewage

    Science.gov (United States)

    Raja, K.; Saravanakumar, A.; Vijayakumar, R.

    2012-11-01

    In this paper, aqueous extract of fresh leaves of Prosopis juliflora was used for the synthesis of silver (Ag) nanoparticles. UV-Vis spectroscopy studies were carried out to asses silver nanoparticles formation within 5 min, scanning electron microscopic was used to characterize shape of the Ag nanoparticles, X-ray diffraction analysis confirms the nanoparticles as crystalline silver and facecentered cubic type and Fourier transform infra-red assed that shows biomolecule compounds which are responsible for reduction and capping material of silver nanoparticles. The anti microbial activity of silver nanoparticle was performed using sewage. The approach of plant-mediated synthesis appears to be cost efficient, eco-friendly and easy methods.

  9. Uranium dioxide calcining apparatus and method

    International Nuclear Information System (INIS)

    Cole, E.A.; Peterson, R.S.

    1978-01-01

    This invention relates to an improved continuous calcining apparatus for consistently and controllably producing from calcinable reactive solid compounds of uranium, such as ammonium diuranate, uranium dioxide (UO 2 ) having an oxygen to uranium ratio of less than 2.2. The apparatus comprises means at the outlet end of a calciner kiln for receiving hot UO 2 , means for cooling the UO 2 to a temperature of below 100 0 C and conveying the cooled UO 2 to storage or to subsequent UO 2 processing apparatus where it finally comes into contact with air, the means for receiving, cooling and conveying being sealed to the outlet end of the calciner and being maintained full of UO 2 and so operable as to exclude atmospheric oxygen from coming into contact with any UO 2 which is at elevated temperatures where it would readily oxidize, without the use of extra hydrogen gas in said means

  10. Process for enriching uranium from seawater

    International Nuclear Information System (INIS)

    Heitkamp, D.; Inden, P.

    1982-01-01

    In selective elutriation of uranium deposited on titanium oxide hydrate by carbonate solution, only uranium should be dissolved from the absorption material forming carbonate compounds, without the deposited ballast ions, above all of magnesium, calcium and sodium being elutriated. The uranium elutriation according to the invention is therefore carried out in the presence of these ballast ions in the same concentrations as those in seawater. The carbonate concentration can only be raised as far as the solubility product of the basic magnesium carbonate permits, so that magnesium remains in the solution, as well as carbonate, in the concentration present in seawater. One must accept the absence of calcium ions in the elutriation solution, as their solubility product with carbonate is considerably less than that for magnesium. (orig./PW) [de

  11. Modes of uranium occurrences in Colorado Front Range

    International Nuclear Information System (INIS)

    Carpenter, R.H.; Gallagher, J.R.L.; Huber, G.C.

    1978-01-01

    This report is an analysis of the various types of uranium occurrences in the Colorado Front Range and the environments in which they developed. The early Proterozoic crust of this region is believed to have been a platform on which intermediate to felsic volcanic centers formed. Some units in the volcanic stratigraphy as well as in the sediments which were deposited in the shallow, intervening seaways are thought to have been uraniferous. Tectonism, occurring about 1.7 By ago, was accompanied and followed by three periods of Precambrian igneous activity. The volcanics and sediments were converted to a metavolcanic-metasedimentary sequence known as the Idaho Springs Formation. Some of the syngenetic uranium remaining in the volcanics and sediments after metamorphism may have been mobilized and incorporated within the Silver Plume plutons and the Pikes Peak batholith and concentrated in pegmatite dikes, pegmatites and fractured areas in the hood zones in the apophyses, or along the flanks of these intrusives. Some or most of the uranium found in these sites may have been generated deeper in the continental plate. Uplift of the Front Range in the Late Mississippian and arching during the Laramide with accompanying faulting set the stage for early and mid-Tertiary igneous activity and associated uranium mineralization. The source of the early and mid-Tertiary uranium mineralization is a point of current debate. Exploration for uranium in the igneous and metamorphic terrain of the Front Range is summarized, and models of each major uranium occurrence are described. Finally, the Front Range exploration potential for uranium is outlined

  12. Gastrointestinal absorption of soluble uranium from drinking water by man

    International Nuclear Information System (INIS)

    Wrenn, M.E.; Singh, N.P.; Ruth, H.; Rallison, M.L.; Burleigh, D.P.

    1989-01-01

    The gastrointestinal absorption of uranium has been measured in ten normal healthy adult volunteers of both sexes by feeding them one litre of water containing 200 to 300 μg of uranium per litre. The water was consumed during normal daytime activities while food was also ingested at its normal rate. Complete collections of urine and faeces were made and compounded on a daily basis over a period of two weeks, one week being prior to the consumption of the uranium-containing water. Uranium was measured by radiochemical separation followed by alpha spectrometry. Both 234 U and 238 U were determined. The results on these people showed that the uptake of uranium under these conditions averaged 0.6%, well below the f 1 of 5% assumed by the ICRP. (author)

  13. Thermodynamic properties of uranium in gallium–aluminium based alloys

    International Nuclear Information System (INIS)

    Volkovich, V.A.; Maltsev, D.S.; Yamshchikov, L.F.; Chukin, A.V.; Smolenski, V.V.; Novoselova, A.V.; Osipenko, A.G.

    2015-01-01

    Activity, activity coefficients and solubility of uranium was determined in gallium-aluminium alloys containing 1.6 (eutectic), 5 and 20 wt.% aluminium. Additionally, activity of uranium was determined in aluminium and Ga–Al alloys containing 0.014–20 wt.% Al. Experiments were performed up to 1073 K. Intermetallic compounds formed in the alloys were characterized by X-ray diffraction. Partial and excess thermodynamic functions of U in the studied alloys were calculated. - Highlights: • Thermodynamics of uranium is determined in Ga–Al alloys of various compositions. • Uranium in the mixed alloys interacts with both components, Ga and Al. • Interaction of U with Al increases with decreasing temperature. • Activity and solubility of uranium depend on Al content in Ga–Al alloys.

  14. Thermodynamic properties of uranium in gallium–aluminium based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Volkovich, V.A., E-mail: v.a.volkovich@urfu.ru [Department of Rare Metals and Nanomaterials, Institute of Physics and Technology, Ural Federal University, Ekaterinburg, 620002 (Russian Federation); Maltsev, D.S.; Yamshchikov, L.F. [Department of Rare Metals and Nanomaterials, Institute of Physics and Technology, Ural Federal University, Ekaterinburg, 620002 (Russian Federation); Chukin, A.V. [Department of Theoretical Physics and Applied Mathematics, Institute of Physics and Technology, Ural Federal University, Ekaterinburg, 620002 (Russian Federation); Smolenski, V.V.; Novoselova, A.V. [Institute of High-Temperature Electrochemistry UD RAS, Ekaterinburg, 620137 (Russian Federation); Osipenko, A.G. [JSC “State Scientific Centre - Research Institute of Atomic Reactors”, Dimitrovgrad, 433510 (Russian Federation)

    2015-10-15

    Activity, activity coefficients and solubility of uranium was determined in gallium-aluminium alloys containing 1.6 (eutectic), 5 and 20 wt.% aluminium. Additionally, activity of uranium was determined in aluminium and Ga–Al alloys containing 0.014–20 wt.% Al. Experiments were performed up to 1073 K. Intermetallic compounds formed in the alloys were characterized by X-ray diffraction. Partial and excess thermodynamic functions of U in the studied alloys were calculated. - Highlights: • Thermodynamics of uranium is determined in Ga–Al alloys of various compositions. • Uranium in the mixed alloys interacts with both components, Ga and Al. • Interaction of U with Al increases with decreasing temperature. • Activity and solubility of uranium depend on Al content in Ga–Al alloys.

  15. Biosynthesis of silver nanoparticles using leaves of Stevia rebaudiana

    International Nuclear Information System (INIS)

    Yilmaz, M.; Turkdemir, H.; Kilic, M. Akif; Bayram, E.; Cicek, A.; Mete, A.; Ulug, B.

    2011-01-01

    Highlights: → Green synthesis of silver nanoparticles using leaves of Stevia Rebaudiana. → Spherical and polydispersed nanoparticles with diameters below 50 nm. → Interplay of nanoparticle formation and aggregation over time. → Capping reagents similar to those in gold synthesis via the same biomass. → Ketones to play active roles in the reduction of silver ions. - Abstract: The synthesis of silver nanoparticles employing a shadow-dried Stevia rebaudiana leaf extract in AgNO 3 solution is reported. Transmission electron microscopy and X-ray diffraction inspections indicate that nanoparticles are spherical and polydispersed with diameters ranging between 2 and 50 nm with a maximum at 15 nm. Ultraviolet-visible spectra recorded against the reaction time confirms the reduction of silver nanoparticles indicating that the formation and the aggregation of nanoparticles take place shortly after the mixing, as they persist concurrently with characteristic times of 48.5 min and 454.5 min, respectively. Aggregation is found to be the dominant mechanism after the first 73 min. Proton nuclear magnetic resonance spectrum of the silver nanoparticles reveals the existence of aliphatic, alcoholic and olefinic CH 2 and CH 3 groups, as well as some aromatic compounds but no sign of aldehydes or carboxylic acids. Infrared absorption of the silver nanoparticles suggests that the capping reagents of silver and gold nanoparticles reduced in plant extracts/broths are of the same chemical composition of different ratios. Ketones are shown to play a somehow active role for the formation of nanoparticles in plant extracts/broths.

  16. Biosynthesis of silver nanoparticles using leaves of Stevia rebaudiana

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, M. [Department of Metallurgy and Materials Engineering, Faculty of Engineering, Bartin University, Bartin (Turkey); Turkdemir, H. [Department of Chemistry, Faculty of Arts and Sciences, Uludag University, 16059 Goeruekle, Bursa (Turkey); Kilic, M. Akif [Department of Biology, Faculty of Science, Akdeniz University, Campus 07058, Antalya (Turkey); Bayram, E. [Department of Chemistry, Faculty of Science, Akdeniz University, Campus 07058, Antalya (Turkey); Cicek, A. [Department of Physics, Faculty of Arts and Sciences, Mehmet Akif Ersoy University, 15100 Burdur (Turkey); Department of Physics, Faculty of Science, Akdeniz University, Campus 07058, Antalya (Turkey); Mete, A. [Department of Chemistry, Faculty of Arts and Sciences, Inonu University, Malatya (Turkey); Ulug, B., E-mail: bulug@akdeniz.edu.tr [Department of Physics, Faculty of Science, Akdeniz University, Campus 07058, Antalya (Turkey)

    2011-11-01

    Highlights: {yields} Green synthesis of silver nanoparticles using leaves of Stevia Rebaudiana. {yields} Spherical and polydispersed nanoparticles with diameters below 50 nm. {yields} Interplay of nanoparticle formation and aggregation over time. {yields} Capping reagents similar to those in gold synthesis via the same biomass. {yields} Ketones to play active roles in the reduction of silver ions. - Abstract: The synthesis of silver nanoparticles employing a shadow-dried Stevia rebaudiana leaf extract in AgNO{sub 3} solution is reported. Transmission electron microscopy and X-ray diffraction inspections indicate that nanoparticles are spherical and polydispersed with diameters ranging between 2 and 50 nm with a maximum at 15 nm. Ultraviolet-visible spectra recorded against the reaction time confirms the reduction of silver nanoparticles indicating that the formation and the aggregation of nanoparticles take place shortly after the mixing, as they persist concurrently with characteristic times of 48.5 min and 454.5 min, respectively. Aggregation is found to be the dominant mechanism after the first 73 min. Proton nuclear magnetic resonance spectrum of the silver nanoparticles reveals the existence of aliphatic, alcoholic and olefinic CH{sub 2} and CH{sub 3} groups, as well as some aromatic compounds but no sign of aldehydes or carboxylic acids. Infrared absorption of the silver nanoparticles suggests that the capping reagents of silver and gold nanoparticles reduced in plant extracts/broths are of the same chemical composition of different ratios. Ketones are shown to play a somehow active role for the formation of nanoparticles in plant extracts/broths.

  17. A novel wound rinsing solution based on nano colloidal silver

    Directory of Open Access Journals (Sweden)

    Soheila Kordestani

    2014-10-01

    Full Text Available Objective(s: The present study aimed to investigate the antiseptic properties of a colloidal nano silver wound rinsing solution to inhibit a wide range of pathogens including bacteria, viruses and fungus present in chronic and acute wounds. Materials and Methods:The wound rinsing solution named SilvoSept® was prepared using colloidal nano silver suspension. Physicochemical properties, effectiveness against microorganism including  Staphylocoocous aureus ATCC 6538P, Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 8739 ,Candida albicans ATCC 10231, Aspergillus niger ATCC 16404, MRSA , Mycobacterium spp. , HSV-1 and H1N1, and biocompatibility tests were carried out according to relevant standards . Results: X-ray diffraction (XRD scan was performed on the sample and verify single phase of silver particles in the compound. The size of the silver particles in the solution, measured by dynamic light scattering (DLS techniqu, ranged 80-90 nm. Transmission electron microscopy (TEM revealed spherical shape with smooth surface of the silver nanoparticles. SilvoSept® reduced 5 log from the initial count of 107 CFU/mL of Staphylocoocous aureus ATCC 6538P, Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 8739, Candida albicans ATCC 10231, Aspergillus niger ATCC 16404, MRSA, Mycobacterium spp. Further assessments of SilvoSept solution exhibited a significant inhibition on the replication of HSV-1 and H1N1. The biocompatibility studies showed that the solution was non-allergic, non-irritant and noncytotoxic. Conclusion: Findings of the present study showed that SilvoSept® wound rinsing solution containing nano silver particles is an effective antiseptic solution against a wide spectrum of microorganism. This compound can be a suitable candidate for wound irrigation.   

  18. Politics of Uranium

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    Uranium is the most political of all the elements, the material for the production of both the large amounts of electricity and the most destructive weapons in the world. The problems that its dual potential creates are only now beginning to become evident. Author Norman Moss looks at this situation and sheds light on many of the questions that emerge. The nuclear issue always comes back to how much uranium there is, what can be done with it, and which countries have it. Starting with a concise history of uranium and explaining its technology in terms the nonspecialist can understand, The Politics of Uranium considers the political issues that technical arguments obscure. It tells the little-known story of the international uranium cartel, explains the entanglements of governments with the uranium trade, and describes the consequences of wrong decisions and blunders-especially the problems of nuclear waste. It also examines the intellectual and emotional roots of the anti-nuclear movement

  19. Uranium resources and supply

    International Nuclear Information System (INIS)

    Cameron, J.

    1973-01-01

    The future supply of uranium has to be considered against a background of forecasts of uranium demand over the next decades which show increases of a spectacular nature. It is not necessary to detail these forecasts, they are well known. A world survey by the Joint NEA/IAEA Working Party on 'Uranium Resources, Production and Demand', completed this summer, indicates that from a present production level of just over 19,000 tonnes uranium per year, the demand will rise to the equivalent of an annual production requirement of 50,000 tonnes uranium by 1980, 100,000 by 1985 and 180,000 by 1990. Few, if any, mineral production industries have been called upon to plan for a near tenfold increase in production in a space of about 15 years as these forecasts imply. This might possibly mean that, perhaps, ten times the present number of uranium mines will have to be planned and engineered by 1990

  20. How much uranium

    International Nuclear Information System (INIS)

    Kenward, M.

    1976-01-01

    Comment is made on the latest of a series of reports on world uranium resources from the OECD's Nuclear Energy Agency and the UN's International Atomic Energy Agency (Uranium resources, production and demand (including other nuclear fuel cycle data), published by the Organisation for Economic Cooperation and Development, Paris). The report categories uranium reserves by their recovery cost and looks at power demand and the whole of the nuclear fuel cycle, including uranium enrichment and spent fuel reprocessing. The effect that fluctuations in uranium prices have had on exploration for new uranium resources is considered. It is stated that increased exploration is essential considering the long lead times involved but that thanks to today's higher prices there are distinct signs that prospecting activities are increasing again. (U.K.)

  1. Uranium Mill Tailings Management

    International Nuclear Information System (INIS)

    Nelson, J.D.

    1982-01-01

    This book presents the papers given at the Fifth Symposium on Uranium Mill Tailings Management. Advances made with regard to uranium mill tailings management, environmental effects, regulations, and reclamation are reviewed. Topics considered include tailings management and design (e.g., the Uranium Mill Tailings Remedial Action Project, environmental standards for uranium mill tailings disposal), surface stabilization (e.g., the long-term stability of tailings, long-term rock durability), radiological aspects (e.g. the radioactive composition of airborne particulates), contaminant migration (e.g., chemical transport beneath a uranium mill tailings pile, the interaction of acidic leachate with soils), radon control and covers (e.g., radon emanation characteristics, designing surface covers for inactive uranium mill tailings), and seepage and liners (e.g., hydrologic observations, liner requirements)

  2. Geochemical exploration for uranium

    International Nuclear Information System (INIS)

    1988-01-01

    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

  3. Classification of Uranium deposits

    International Nuclear Information System (INIS)

    Dahlkamp, F.J.

    1978-01-01

    A listing of the recognized types of uranium mineralization shows nineteen determinable types out of which only six can be classified as of economic significance at present: Oligomiitic quartz pebble conglomerates, sandstone types, calcretes, intra-intrusive types, hydrothermal veins, veinlike types. The different types can be genetically related to prevalent geological environments, i.e. 1. the primary uranium occurrences formed by endogenic processes, 2. the secondary derived from the primary by subsequent exogenic processes, 3. the tertiary occurrences are assumed to be formed by endogenic metamorphic processes, although little is known about the behaviour of the uranium during the metamorphosis and therefore the metallogenesis of this tertiary uranium generation is still vague. A metallotectonic-geochronologic correlation of the uranium deposits shows a distinct affinity of the uranium to certain geological epochs: The Upper Archean, Lower Proterozoic, the Hercynian and, in a less established stage, the Upper Proterozoic. (orig.) 891 HP/orig. 892 MKO [de

  4. Uranium Newsletter. No. 1

    International Nuclear Information System (INIS)

    1987-03-01

    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

  5. Uranium purchases report 1992

    International Nuclear Information System (INIS)

    1993-01-01

    Data reported by domestic nuclear utility companies in their responses to the 1991 and 1992 ''Uranium Industry Annual Survey,'' Form EIA-858, Schedule B ''Uranium Marketing Activities,are provided in response to the requirements in the Energy Policy Act 1992. Data on utility uranium purchases and imports are shown on Table 1. Utility enrichment feed deliveries and secondary market acquisitions of uranium equivalent of US DOE separative work units are shown on Table 2. Appendix A contains a listing of firms that sold uranium to US utilities during 1992 under new domestic purchase contracts. Appendix B contains a similar listing of firms that sold uranium to US utilities during 1992 under new import purchase contracts. Appendix C contains an explanation of Form EIA-858 survey methodologies with emphasis on the processing of Schedule B data

  6. Process for continuous production of metallic uranium and uranium alloys

    Science.gov (United States)

    Hayden, Jr., Howard W.; Horton, James A.; Elliott, Guy R. B.

    1995-01-01

    A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO.sub.3), or any other substantially stable uranium oxide, to form the uranium dioxide (UO.sub.2). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl.sub.4), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation.

  7. Process for continuous production of metallic uranium and uranium alloys

    Science.gov (United States)

    Hayden, H.W. Jr.; Horton, J.A.; Elliott, G.R.B.

    1995-06-06

    A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO{sub 3}), or any other substantially stable uranium oxide, to form the uranium dioxide (UO{sub 2}). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl{sub 4}), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation. 4 figs.

  8. New french uranium mineral species

    International Nuclear Information System (INIS)

    Branche, G.; Chervet, J.; Guillemin, C.

    1952-01-01

    In this work, the authors study the french new uranium minerals: parsonsite and renardite, hydrated phosphates of lead and uranium; kasolite: silicate hydrated of uranium and lead uranopilite: sulphate of uranium hydrated; bayleyite: carbonate of uranium and of hydrated magnesium; β uranolite: silicate of uranium and of calcium hydrated. For all these minerals, the authors give the crystallographic, optic characters, and the quantitative chemical analyses. On the other hand, the following species, very rare in the french lodgings, didn't permit to do quantitative analyses. These are: the lanthinite: hydrated uranate oxide; the α uranotile: silicate of uranium and of calcium hydrated; the bassetite: uranium phosphate and of hydrated iron; the hosphuranylite: hydrated uranium phosphate; the becquerelite: hydrated uranium oxide; the curite: oxide of uranium and lead hydrated. Finally, the authors present at the end of this survey a primary mineral: the brannerite, complex of uranium titanate. (author) [fr

  9. Uranium demand. An exploration challenge

    Energy Technology Data Exchange (ETDEWEB)

    Roux, A J.A.

    1976-10-01

    The estimated world resources of uranium as well as the estimated consumption of uranium over the next 25 years are briefly discussed. Attention is also given to the prospecting for uranium in South Africa and elsewhere in the world.

  10. Chapter 3. Classical method of uranium leaching from ores and reasons for incomplete recovery at dumps of State Enterprise 'VOSTOKREDMET'. 3.3. Basic regularities of uranium ores leaching

    International Nuclear Information System (INIS)

    Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

    2012-01-01

    Present article is devoted to basic regularities of uranium ores leaching. It was found that the basic method of uranium ores enrichment and producing of reasonably rich and pure uranium concentrates (usually technical uranium oxide) is a chemical concentration concluded in selective uranium leaching from ore raw materials with further, uranium compounds - so called uranium chemical concentrates. Such reprocessing of uranium ores with the purpose of uranium chemical concentrates production, currently, are produced everywhere by hydrometallurgical methods. This method in comparison with enrichment and thermal reprocessing is a universal one. Hydrometallurgy - the part of chemical technology covering so called moist methods of metals and their compounds (in the current case, uranium) extraction from raw materials, where they are contained. It can be ores or ore concentrates produced by radiometric, gravitational, floatation enrichment, sometimes passed through high-temperature reprocessing or even industry wastes. The basic operation in hydrometallurgy is its important industrial element - metal or metals leaching as one or another compound. Leaching is conversion of one or several components to solution under impact of relevant technical solvents: water, water solutions, acids, alkali or base, solution of some salts and etc. The basic purpose of leaching in uranium technology is to obtain the most full and selective solution of uranium.

  11. Structure of some complex halides of uranium(III)

    International Nuclear Information System (INIS)

    Volkov, V.A.; Suglobova, I.G.; Chirkst, D.E.

    1987-01-01

    Polycrystals of some halide complexes of uranium(III) were obtained and investigated by x-ray diffraction. The M 2 UCl 5 compounds (M = K, Rb) are isostructural with K 2 PrCl 5 ; RbU 2 Cl 7 is of the same type as RbDy 2 Cl 7 or KDy 2 Cl 7 . The coordination number of the uranium is 7. The M 2 UBr 5 compounds (M = K-Cs) are isostructural with Cs 2 DyCl 5 , and the coordination number of the uranium is 6. Rb 2 NaUCl 6 is a 12L-hexagonal polytype, the structural analog of Cs 2 NaCrF 6 . The most characteristic coordination number of uranium in the UHal 3 -MHal systems is 8 for Hal = F, 7 for Hal = Cl, and 6 for Hal = Br

  12. Uranium industry annual, 1988

    International Nuclear Information System (INIS)

    1989-01-01

    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

  13. Gold and uranium extraction

    International Nuclear Information System (INIS)

    James, G.S.; Davidson, R.J.

    1977-01-01

    A process for extracting gold and uranium from an ore containing them both comprising the steps of pulping the finely comminuted ore with a suitable cyanide solution at an alkaline pH, acidifying the pulp for uranium dissolution, adding carbon activated for gold recovery to the pulp at a suitable stage, separating the loaded activated carbon from the pulp, and recovering gold from the activated carbon and uranium from solution

  14. Uranium mine ventilation

    International Nuclear Information System (INIS)

    Katam, K.; Sudarsono

    1982-01-01

    Uranium mine ventilation system aimed basically to control and decreasing the air radioactivity in mine caused by the radon emanating from uranium ore. The control and decreasing the air ''age'' in mine, with adding the air consumption volume, increasing the air rate consumption, closing the mine-out area; using closed drainage system. Air consumption should be 60m 3 /minute for each 9m 2 uranium ore surfaces with ventilation rate of 15m/minute. (author)

  15. Pine Creek uranium province

    International Nuclear Information System (INIS)

    Bower, M.B.; Needham, R.S.; Page, R.W.; Stuart-Smith, P.G.; Wyborn, L.A.I.

    1985-01-01

    The objective of this project is to help establish a sound geological framework of the Pine Creek region through regional geological, geochemical and geophysical studies. Uranium ore at the Coronation Hill U-Au mine is confined to a wedge of conglomerate in faulted contact with altered volcanics. The uranium, which is classified as epigenetic sandstone type, is derived from a uranium-enriched felsic volcanic source

  16. Uranium in Canada

    International Nuclear Information System (INIS)

    1985-09-01

    In 1974 the Minister of Energy, Mines and Resources (EMR) established a Uranium Resource Appraisal Group (URAG) within EMR to audit annually Canada's uranium resources for the purpose of implementing the federal government's uranium export policy. A major objective of this policy was to ensure that Canadian uranium supplies would be sufficient to meet the needs of Canada's nuclear power program. As projections of installed nuclear power growth in Canada over the long term have been successively revised downwards (the concern about domestic security of supply is less relevant now than it was 10 years ago) and as Canadian uranium supply capabilities have expanded significantly. Canada has maintained its status as the western world's leading exporter of uranium and has become the world's leading producer. Domestic uranium resource estimates have increased to 551 000 tonnes U recoverable from mineable ore since URAG completed its last formal assessment (1982). In 1984, Canada's five primary uranium producers employed some 5800 people at their mining and milling operations, and produced concentrates containing some 11 170 tU. It is evident from URAG's 1984 assessment that Canada's known uranium resources, recoverable at uranium prices of $150/kg U or less, are more than sufficient to meet the 30-year fuelling requirements of those reactors that are either in opertaion now or committed or expected to be in-service by 1995. A substantial portion of Canada's identified uranium resources, recoverable within the same price range, is thus surplus to Canadian needs and available for export. Sales worth close to $1 billion annually are assured. Uranium exploration expenditures in Canada in 1983 and 1984 were an estimated $41 million and $35 million, respectively, down markedly from the $128 million reported for 1980. Exploration drilling and surface development drilling in 1983 and 1984 were reported to be 153 000 m and 197 000 m, respectively, some 85% of which was in

  17. Uranium production from phosphates

    International Nuclear Information System (INIS)

    Ketzinel, Z.; Folkman, Y.

    1979-05-01

    According to estimates of the world's uranium consumption, exploitation of most rich sources is expected by the 1980's. Forecasts show that the rate of uranium consumption will increase towards the end of the century. It is therefore desirable to exploit poor sources not yet in use. In the near future, the most reasonable source for developing uranium is phosphate rock. Uranium reserves in phosphates are estimated at a few million tons. Production of uranium from phosphates is as a by-product of phosphate rock processing and phosphoric acid production; it will then be possible to save the costs incurred in crushing and dissolving the rock when calculating uranium production costs. Estimates show that the U.S. wastes about 3,000 tons of uranium per annum in phosphoric acid based fertilisers. Studies have also been carried out in France, Yugoslavia and India. In Israel, during the 1950's, a small plant was operated in Haifa by 'Chemical and Phosphates'. Uranium processes have also been developed by linking with the extraction processes at Arad. Currently there is almost no activity on this subject because there are no large phosphoric acid plants which would enable production to take place on a reasonable scale. Discussions are taking place about the installation of a plant for phosphoric acid production utilising the 'wet process', producing 200 to 250,000 tons P 2 O 5 per annum. It is necessary to combine these facilities with uranium production plant. (author)

  18. 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

  19. Uranium concentration in fossils

    International Nuclear Information System (INIS)

    Okano, J.; Uyeda, C.

    1988-01-01

    Recently it is known that fossil bones tend to accumulate uranium. The uranium concentration, C u in fossils has been measured so far by γ ray spectroscopy or by fission track method. The authors applied secondary ion mass spectrometry, SIMS, to detect the uranium in fossil samples. The purpose of this work is to investigate the possibility of semi-quantitative analyses of uranium in fossils, and to study the correlation between C u and the age of fossil bones. The further purpose of this work is to apply SIMS to measure the distribution of C u in fossil teeth

  20. METHOD OF ROLLING URANIUM

    Science.gov (United States)

    Smith, C.S.

    1959-08-01

    A method is described for rolling uranium metal at relatively low temperatures and under non-oxidizing conditions. The method involves the steps of heating the uranium to 200 deg C in an oil bath, withdrawing the uranium and permitting the oil to drain so that only a thin protective coating remains and rolling the oil coated uranium at a temperature of 200 deg C to give about a 15% reduction in thickness at each pass. The operation may be repeated to accomplish about a 90% reduction without edge cracking, checking or any appreciable increase in brittleness.