On uranium

These variations permit the separation of other components, if desired. Additional data on uranium, plutonium, and nitric acid distribution coefficients as a function of TBP concentration, solvent saturation, and salting strength are available (24,25). Algorithms have also been developed for the prediction of fission product distributions in the PUREX process (23). 

The role of the reactor may be either as a converter, which produces some plutonium by neutron absorption in uranium-238 but depends on uranium-235 for most of the fission, or as a breeder, which contains a large amount of plutonium and produces more fissile material than it consumes. Breeding is also possible using uranium-233 produced by neutron absorption in thorium-232. 

Action of chlorine on uranium oxide to recover volatile uranium chloride Removal of iron oxide impurity from titanium oxide by volatilization hy action of chlorine... 

Figure 8.16. Comparison of calculation and experiment for explosive implosion fragmentation data on uranium cylindrical shells.

Spinels. There are limited experimental data on uranium and thorium partitioning between magnetite and melt (Nielsen et al. 1994 Blundy and Brooker 2003). Both studies find U and Th to be moderately incompatible. Blundy and Brooker s results for a hydrous dacitic melt at 1 GPa and 1025°C give Du and D h. of approximately 0.004. The accuracy of these values is compromised by the very low concentrations in the crystals and the lack of suitable SIMS secondary standards for these elements in oxide minerals. Nonetheless, these values are within the range of Djh of magnetites at atmospheric pressure 0.003-0.025 (Nielsen et al. 1994). It is difficult to place these values within the context of the lattice strain model, firstly because there are so few systematic experimental studies of trace element partitioning into oxides and secondly because of the compositional diversity of the spinels and their complex intersite cation ordering. 

Shen C-C, Edwards RL, Cheng H, Dorale JA, Thomas RB, Moran SB, Weinstein S, Edmonds HN (2002) Uranium and thorium isotopic and concentration measurements by magnetic sector inductively coupled plasma mass spectrometry. Chem Geol 185 165-178 Shen GT, Dunbar RB (1995) Environmental controls on uranium in reef corals. Geochim Cosmochim Acta 59 2009-2024... 

Yuan SX, Chen TM, Gao SJ, Hu YQ (1991) Study on uranium series dating of fossil bones from Zhoukoudian sites Acta Anthropol. Sinica 10 189-193 (in Chinese)... 

The present account on uranium begins with some of the basic elements of chemistry used in the hydrometallurgy of uranium. Although the inorganic chemistry of uranium, is quite... 

Homopolymerization of Butadiene. It appeared to us that catalysts based on f-transition metals were the ones most likely to enable us to prepare polybutadiene with an extremely high cis content. We began by investigating catalysts based on uranium compounds. Two such systems were known at the beginning of our work. 

The polymerization is normally carried out in non-aromatic solvents, such as cyclohexane and n-hexane, at temperatures of 50 to 90 °C.Temperatures within this range influence the stereospecificity of the polymerization to only a small extent. These catalysts, unlike ones based on uranium, do not have to be preformed. ... 

The actinide SMMs discussed so far were based on uranium. In 2011, the first mononuclear transuranic SMM in the form of the Np4+ complex [Np(COT)2] (10, COT = cyclooctatetraene, C8H82-), was published [9]. Although first published in 1970, the dynamics of its magnetic moment had never been investigated. The relaxation is slow enough to be measured when applying an external dc magnetic... 

Chem., 40, 3516 (2001). Solvent Effects on Uranium(VI) Fluoride and Hydroxide Complexes Studied by EXAFS and Quantum Chemistry. 

Nuclear power plants are based on uranium mined in surface mines, or by in situ leaching. 

Evaluated in NEA-TDB review on uranium diermodynamics [37] using ( 4+ C1O4) (0-76 0.06). Taken from Bruno [38], where die following assumptions were made e... 

Geochemical controls on uranium precipitation in calcrete palaeochannel deposits of Namibia... 

The aim of this work is to further characterize the different generations of uranium oxide from three basement-hosted deposits the Miiiennium, Eagie Point, and P-Patch with muitipie micro-scaie anaiysis techniques. The resuits wiii be compared to those previousiy obtained on uranium oxides from deposits iocated in the vicinity of the unconformity to evaiuate the previousiy proposed ore formation modeis. 

Similar ages were obtained on Athabasca Basin deposits for mineralizations located in the vicinity of the unconformity or partly in the basement (McArthur River or Cigar Lake for example). The oldest ages obtained on uranium oxides from several deposits (i.e, Alexandre et al. 2009) have not been obtained in the present study. Such a feature could be linked either to lack of uranium deposition in the basement during this period or to the dissolution of the first U-oxides generations by later fluid circulation events. 

The rate and quantity of radon and uranium contributed to waters exposed to mineralized outcrops and the subsequent mobility of these elements in the present day environment has not been previously documented. This paper presents the results from leaching experiments carried out on uranium-enriched Horton Group sandstones in the Windsor area of Nova Scotia. Understanding of these processes is important both to environmental and exploration geochemistry. 

Thorium is commonly found in combination with other actinide elements, with organic and inorganic chemicals, and with acids and bases during occupational exposure. The health effects of occupational exposures to thorium on humans, therefore, cannot necessarily be attributed to thorium. The daughter products of thorium have unique properties that also add to the radiological toxicity of thorium. For further information, see the toxicological profiles on uranium, radon, and radium. 

Uranium hexafluoride is prepared by the reaction of fluorine on uranium metal, triuranium octafluoride, uranium pentachloride, or uranium carbide. 

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