Uranium 234, which is a member of the uranium series the decay chain of uranium 238, decays to lead206 through a series of relatively shortlived isotopes. Results are reported of metallographic examinations of ual, ufe, and ualfe alloys, and tentative phase diagrams are given for all three systems. First we construct an orbital degenerate hubbard model for uranium compounds based on a jj coupling scheme. Jingming shi, wenwen cui, silvana botti, and miguel a. Ternary diagram for uranium, thorium, and potassium17 5.
Bashlykov soviet atomic energy volume 27, pages 17 26 1969cite this article. Crouch pembroke college, oxford, england received 17 february 1969 abstract the uceo ternary phase diagram has been constructed between uo2. By analyzing the model in the cubic system, we obtain the phase diagram including several kinds of magnetic states. Only one attempt to observe and build a phase diagram for the ternary rhenium oxides was carried out baorere2o7 6.
Ternary compounds of uraniumcarbon and the group viii a. Thus, the connected phase diagram shows that uranium, neptunium, and plutonium exhibit lowsymmetry groundstate structures rather than highsymmetry structures, which are found in most metals. The oxygen then binds to silicon as well as uranium, forming a strong siliconoxygen bond. Separation of systems based on uranium hexafluoride and. The electron configuration of uranium is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f3 6s2 6p6 6d1 7s2. This is because of the relevance of the appropriate ternary. Systems of uranium and plutonium with carbon, oxygen, and nitrogen. Areva is the operator of the mcclean lake uranium mill and a major partner. Its high radioactivity makes uranium subject to special handling techniques and precautions. Therefore th electron configuration for uranium must end as 5f4, 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5 p6 6s2 4e14 5d10 6p6 7s2 5f4 this notation can be written in core notation or noble gas notation.
The critical analysis of all these experimental investigations has led to select only edwards and martins and cleavess data for the optimization. Annual world wide production is around 35,000 tons. U 2 n 3 phase was observed as the reaction temperature increased, corresponding to a continuous. Maps showing concentrations of uranium and thor ium19 6. Progress is reported of a research program on deterinining the ual fe constitution diagram up to approximates ppm each of al and fe. The atomic bomb that was used at hiroshima in world war 2, was uranium based.
This reaction will proceed at high speed, the time for an emitted neutron to collide with another nucleus to produce a second fission is about 0. The phase diagrams of the quasi ternary zro2y2o3ceo2 system in the zirconiarich corner are estimated at different temperatures with a substitutional model and muggianus extrapolation. Xray diffraction and structural refinement showed that about 21. Thermodynamic assessment of the uraniumoxygen system. Nuclear thermodynamic database archive ouverte hal. Ternary utho phase diagrams proposed by paul and keller 148 and based on a htxrd study.
Printed in northern ireland the uraniumplutoniumoxygen ternary phase diagram t. In the uranium rich side of the diagram, the experimental data on the oxygen solubility limit in liquid uranium show a strong disagreement. As the second largest lanthanide fission product of 235 u, cerium can significantly affect the local structure of u in nuclear fuel,, although its cumulative yield is only about 5%. Phase studies in the uranium hafnium system by donald joseph beerntsen a dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of doctor of philosophy major subject. Re at the expense of uranium where re denotes rare earth alloy of cerium.
Therefore th electron configuration for uranium must end as 5f4, 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5 p6 6s2 4e14 5d10 6p6 7s2 5f4 this notation can be written in core notation or noble gas notation by replacing the1s2 2s2 2p6 3s. Full text of bibliography on the high temperature chemistry. Advances in the experimental determination of the uranium. The effects of oxygen and nitrogen, which are present in these alloys as contaminants, on alloy constitution ars shownin the more form of ternary diagrams and in terms of their quantitative effects on the phases present. Thermodynamic modeling of uranium and oxygen containing ternary systems with gadolinium, lanthanum, and thorium. Full text of chemical analysis of tungstenuranium dioxide. A diagram of such a reaction is shown in the diagram above. In the parameter region corresponding to actual uranium compounds, the phase diagram suggests successive transitions among paramagnetic, magnetic metallic, and insulating neel states, consistent with the experimental results for. High density penetrators military ballast for reentry aircrafts. Areva is a leading producer of uranium, accounting for the processing of about half of the uranium concentrate produced in canada.
Thermodynamic modeling of uranium and oxygen containing. Comprehensive information for the element uranium u is provided by this page including scores of properties, element names in many languages, most known nuclides and technical terms are linked to their definitions. Uranium is a carcinogen, that is, it causes cancer. As in other nuclear fission processes, other uncharged particles such as multiple neutrons and gamma rays are produced in ternary fission ternary fission may happen during neutroninduced fission or in spontaneous fission the type. Uranium 233 is made from thorium232 by neutron bombardment, usually in a nuclear reactor, and 233 u is also fissile. Criteria determining the selection of slags for the melt. Publications calypso an efficient structure prediction. The electron configuration for uranium u is based upon the placement of uranium in the fourth column of the actinide series or f block. Crouch pembroke college, oxford, england received 17 february 1969 abstractthe uceo ternary phase. Printed in great britain the uraniumceriumoxygen ternary phase diagram t. It is a silverygrey metal in the actinide series of the periodic table. Areva is the operator of the mcclean lake uranium mill and a major partner in the cigar lake, mcarthur river and key lake operations located in northern saskatchewan.
Uranium 235 is a fissile isotope and its fission crosssection for thermal neutrons is about 585 barns for 0. In charge of major work iowa state college ames, iowa 1958 signature was redacted for privacy. Uranium is a radioactive element with atomic symbol u, atomic number 92, and atomic weight 238. Thermodynamic modelling of the plutoniumoxygen system core. However, when they analysed the products they found not elements heavier than uranium but two about half the mass number of the original uranium, a solution that had been suggested in 1938 by lisa meitner and otto frisch. Nci thesaurus ncit uranium is a common naturally occurring and radioactive substance. In addition, a rietveld refinement of monoclinic na2puo3, in space group c2c, is reported for the first time, and the existence of. Full text of chemical analysis of tungstenuranium dioxide materials see other formats. If uranium can be put into a gaseous form, then the molecules containing the lighter u235 will have a. Uranium martin heinrich klaproth on the periodic table physical properties where its found location on the periodic table the points the price bohr diagram uses what compound is it in. Full text of bibliography on the high temperature chemistry and physics of materials, july, august. Crouch pembroke college, oxford, england received 17 february 1969 abstractthe uceo ternary phase diagram has been constructed between uo2. Preparation of uranium carbide through carbothermic. The uraniumceriumoxygen ternary phase diagram sciencedirect.
Uranium cerium mixed oxides exist in various processes of nuclear fuel cycle. Ternary compounds of uranium and carbon with the first row elements of group viii a in the periodic table have been known for some time. The analysis of the binary and ternary phase diagrams allowed the listing of all the possible phases in the. Pdf phase equilibria in the uraniumplutoniumoxygen. U2n3 phase was observed as the reaction temperature increased, corresponding to a continuous removal of nitrogen. Uranium is a chemical element with the symbol u and atomic number 92. Jun 18, 2014 the electron configuration for uranium u is based upon the placement of uranium in the fourth column of the actinide series or f block. Most of absorption reactions result in fission reaction, but a minority results in radiative capture forming 236 u. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons.
Jan 16, 2008 the oxygen then binds to silicon as well as uranium, forming a strong siliconoxygen bond. Reduction of oxides to a substoichiometric composition where z 035 in the general formula u 1. A compound xi whose homogeneity range embraces the compositions uzrsub 2 and uzrsub 3 is present in the latter system, and the form of diagram in more. The crystal structure of uranium dioxide is facecentered cubic fcc with lattice constant a 0 5. Due to its complex phase diagram and the employment of uo2 as a nuclear fuel, the binary system uo is of great interest both scientific and technological. For the radium isotopes, further validation was made by intercomparison with other methods for a set of routine samples with low concentrations of radium in them. A compound xi whose homogeneity range embraces the compositions uzrsub 2 and uzrsub 3 is present in the latter system, and the form of diagram in more this. There is general agreement between published versions of the uranium titanium phase diagram, but certain aspects of the uranium zirconium system are still controversial. Phases and phase relations in thebinary oxide systems. Numerous experimental and theoretical studies have been carried out in the last 45 years in order to determine the properties of this system, leading to a precise definition of a considerable part of the state diagram in the region. A new look at the structural properties of trisodium.
Ternary and quaternary phases in the alkaliearth rhenium. Phase studies of uraniumzirconium alloys technical. The constitution of zirconium uranium alloys is discussed, and a constitutional diagram for the system is presented. These low oxygen solubility data in liquid uranium are consistent with the experimental tieline. Alloys of aluminum, thorium, and uranium abstract the aluminumrich corner of the ternary alloy system aluminumthoriumuranium has been investigated by thermal and microscopic analyses to determine an area of lowmelting alloys that could be used as a liquid metal fuel in uranium233 breeder reactors. Uranium metal is silvercolored with a gray surface and is nearly as strong as steel. Uranium, radium and thorium in soils with highresolution. Separation of systems based on uranium hexafluoride and some. Before this new insight, the lowsymmetry ground state of plutonium was attributed to directional or covalentlike bonding. Modeling of uranium and oxygen containing ternary systems with gadolinium, lanthanum, and. Spin and orbital structure of uranium compounds based on a.
A new tetragonal phase t ce1xzrxo2, which was attained by cyclic redox process together with annealing in o2 gas at 23 or 1423 k, exhibited a sharp oxygen release at the highest. Uranium tetrachloride ucl4 uranium tetrafluoride uf4 interesting facts. The purpose of this paper is to present the results of the comprehensive study of the phase equilibriums liquidsolid and liquidvapour in binary and ternary systems, formed by uranium hexafluoride, bromine trifluoride and iodine pentafluoride. Full text of chemical analysis of tungstenuranium dioxide materials. Estimation of isothermal sections of ternary phase diagrams. Criteria determining the selection of slags for the melt decontamination of radioactively contaminated stainless steel by electroslag remelting joanna m.
Marques nitrogenhydrogenoxygen ternary phase diagram. Natural uranium is a mixture of three types or isotopes called u234 234 u, u235 235 u and u238 238 u. Schematic map showing areas of relative traceelement enr ichments20 7. Uranium is a common naturally occurring and radioactive substance. Mcmurray, jacob wesley, thermodynamic modeling of uranium and oxygen containing. To zoom back out and see the entire diagram, click top menu view, best fit. Journal of phase equilibria and diffusion rg journal impact. This volume is part of the series on chemical thermodynamics, published under the aegis of the oecd nuclear energy agency, and updates and expands the thermodynamic data on inorganic compounds and complexes of uranium, neptunium, plutonium, americium and technetium contained in the previous volumes of the series.
New phases at high pressure form structural prediction phys. Defect structure and the phase diagram of uranium dioxide. Structural properties and charge distribution of the. For cedoped compositions prepared with the trivalent precursor, the. For fast neutrons its fission crosssection is on the order of barns. Phase equilibria in the uraniumplutoniumoxygen ternary phase diagram at u0. This particular reaction doesnt work in the presence of air or water, so it wont be much use in the.
Find out about its chemical and physical properties, states, energy, electrons, oxidation and more. Uranium dicarbide is tetragonal in the most common phase, uc 2 that has the composition uc 1. Uranium is weakly radioactive because all isotopes of uranium are unstable. Areva has been exploring for uranium, developing uranium mines and producing uranium concentrate in canada for more than 50 years. The mechanism and kinetics of decomposition of the gamma. Crystal structures of the obtained phases have been investigated by the rietveld method using conventional xray powder diffraction technique. Phase studies in the uraniumhafnium system by donald joseph beerntsen a dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of doctor of philosophy major subject. Numerous experimental and theoretical studies have been carried out in the last 45 years in order to determine the properties of this system, leading to a precise definition of a considerable part of. Full text of bibliography on the high temperature chemistry and physics of materials, july, august, september 1969. The reaction mechanism and kinetics of the thermal decomposition of uranium dinitrideuranium sesquinitride to uranium mononitride under inert atmosphere at elevated temperature were studied. Printed in great britain the uranium cerium oxygen ternary phase diagram t.
To close all diagram windows before exiting the ped application, choose file exit all top left of diagram window the ped editor, completed in 2012, is part of new custom software now used by the data center to digitize all diagrams for this database. Assuming that the nuclei split into two equal halves and produce three. Spin and orbital structure of uranium compounds based on a j. It is a normal part of rocks, soil, air, and water, and it occurs in nature in the form of minerals but never as a metal. Webelements periodic table uranium biological information. The aqueous phase flows through the stationary resin held in a column, and the net effect of all the chemical reactions is a band of uranium that moves through the ionexchange column. Because of the radiation hazard, uranium and its compounds should only ever be handled by properly trained professionals in a properly accredited institution. A consistent set of experimental data was selected among the numerous data on the phase diagram and oxygen chemical potential. The u ce o ternary phase diagram has been constructed between uo 2u 3 o 8 and ceo 2ceo 1818 for all concentrations of ce and for temperatures between room temperature and 600c, from results obtained using a hightemperature xray powder diffraction camera. As in other nuclear fission processes, other uncharged particles such as multiple neutrons and gamma rays are produced in ternary fission.
Street chemistry division, aere, harwell, didcot, berks received 21 march 1967 abstractthe upuo phase diagram has been constructed between uoi. The plutonium oxygen phase diagram a tentative phase diagram was. A numerical approach is presented for the segregation of atomic oxygen at agmgo. The u ce o ternary phase diagram has been constructed between uo2u3o8 and ceo2ceo1818 for all. This software can be applied to stored or usersupplied thermodynamic. This is mainly because cerium can be dissolved in uo 2 to form u 1y ce y o 2 solid solutions in wide. In this paper, the existing data on the gamma stability of binary and ternary uranium alloys is analyzed. Certain alloys are metastable for very long times at the relatively low fuel temperatures seen in research reactor operation.
Structural properties and charge distribution of the sodium. The uranium nucleus had split in half this was the first evidence of what is called nuclear fission. The crosssection for radiative capture for thermal neutrons. Systems of uranium and plutonium with carbon, oxygen, and. However, information for other alkaliearth rhenium oxygen systems is very scarce. Uranium 92 u your user agent does not support the html5 audio element. Primary uranium bearing ores are uraninite, autunite, carnotite, samarskite some varieties of samarskite contain up to 23% uranium and torbernite. Uranium provides tools for dependency management, reuse of assembly scripts, configuration, and other common requirements for an assembly system. Uranium is a radioactive element denoted by the chemical symbol u.
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