Uranium behavior

Measuring the isotopic composition of U in estuaries has the potential for further constraining the interpretations of uranium behavior. However, this has been hampered by large uncertainties in conventional methods using counting techniques. While rivers often display ( " U/ U) activity ratios above equilibrium, the ratios generally do not... 

Martin JB, Cable JE, Swarzenski PW (2000) Quantification of groundwater discharge and nutrient loading to the Indian River Lagoon. St. Johns River Water Management District Report, Palatka FI Martin J-M, Meybeck M, Pusset M (1978a) Uranium behavior in the Zaire estuary. Netherlands J Sea Res 12 338-344... 

Martin J-M, Nijampurkar V, Salvadori F (1978b) Uranium and thorium isotope behavior in estuarine systems. In Biogeochemistiy of Estuarine Sediments. Goldberg ED (ed) UNESCO, Paris p 111-127 McKee BA, Todd JF (1993) Uranium behavior in a permanently anoxic Qord microbial control Limnol Oceanogr 38 408-414... 

McKee, B.A., and Todd, J.F. (1993) Uranium behavior in a permanently anoxic fjord microbial control Limnol. Oceanogr. 38, 408—414. 

U/ U ratios as tracers in springs and small streams, and these have mainly used uranium isotopes to trace the interaction of groundwater with surface water (e.g., Lienert et al., 1994). Lienert et al. (1994) attempted to link changes in uranium behavior to decreases in the anthropogenic inputs of phosphorous, which in turn affects biological activity and redox conditions within waters. As discussed in an earlier section of this chapter, the ratio has... 

Jia G, Belli M, Sansone U, Rosamilia S, Gaudino S (2004) Concentration, distribution and characteristics of depleted uranium in the Kosovo ecosystem a comparison with some uranium behaviors in the normtil environment. J Radioanal Nucl Chem 260 481 94... 

Gr. aktis, aktinos, beam or ray). Discovered by Andre Debierne in 1899 and independently by F. Giesel in 1902. Occurs naturally in association with uranium minerals. Actinium-227, a decay product of uranium-235, is a beta emitter with a 21.6-year half-life. Its principal decay products are thorium-227 (18.5-day half-life), radium-223 (11.4-day half-life), and a number of short-lived products including radon, bismuth, polonium, and lead isotopes. In equilibrium with its decay products, it is a powerful source of alpha rays. Actinium metal has been prepared by the reduction of actinium fluoride with lithium vapor at about 1100 to 1300-degrees G. The chemical behavior of actinium is similar to that of the rare earths, particularly lanthanum. Purified actinium comes into equilibrium with its decay products at the end of 185 days, and then decays according to its 21.6-year half-life. It is about 150 times as active as radium, making it of value in the production of neutrons. 

The corrosion behavior of plutonium metal has been summarized (60,61). a-Plutonium oxidizes very slowly in dry air, typically <10 mm/yr. The rate is accelerated by water vapor. Thus, a bright metal surface tarnishes rapidly in normal environments and a powdery surface soon forms. Eventually green PUO2 [12059-95-9] covers the surface. Plutonium is similar to uranium with respect to corrosion characteristics. The stabilization of 5-Pu confers substantial corrosion resistance to Pu in the same way that stabilization of y-U yields a more corrosion-resistant metal. The reaction of Pu metal with Hquid water produces both oxides and oxide-hydrides (62). The reaction with water vapor above 100°C also produces oxides and hydride (63). 

In 1896, Becquerel discovered that uranium was radioactive (3). Becquerel was studying the duorescence behavior of potassium uranyl sulfate, and observed that a photographic plate had been darkened by exposure to the uranyl salt. Further investigation showed that all uranium minerals and metallic uranium behaved in this same manner, suggesting that this new radioactivity was a property of uranium itself In 1934, Fermi bombarded uranium with neutrons to produce new radioactive elements (4). 

Oxo Ion Salts. Salts of 0x0 anions, such as nitrate, sulfate, perchlorate, iodate, hydroxide, carbonate, phosphate, oxalate, etc, are important for the separation and reprocessing of uranium, hydroxide, carbonate, and phosphate ions are important for the chemical behavior of uranium ia the environment (150—153). 

Carbonates. Actinide carbonate complexes are of interest not only because of their fundamental chemistry and environmental behavior (150), but also because of extensive industrial appHcations, primarily in uranium recovery from ores and nuclear fuel reprocessing. 

The chemistry of plutonium is unique in the periodic table. This theme is exemplified throughout much of the research work that is described in this volume. Many of the properties of plutonium cannot be estimated accurately based on experiments with lighter elements, such as uranium and neptunium. Because massive amounts of plutonium have been and are being produced throughout the world, the need to define precisely its chemical and physical properties and to predict its chemical behavior under widely varying conditions will persist. In addition to these needs, there is an intrinsic fundamental interest in an element with so many unusual properties and with so many different oxidation states, each with its own chemistry. 

Behavior of soluble plutonium and uranium in Pond 3513, located at the Oak Ridge National Laboratory. The water concentrations (Bq/m3) represent the period March 1977 through June 1982(26). 

Experiments on the sky. Two experiments have been carried out at the sky, using two laser installations built for the American and French programmes for Uranium isotope separation, respectively AVLIS at the Lawrence Livermore Nat l Lab (California) in 1996 and SILVA at CEA/Pierrelatte (Southern France) in 1999. The average power was high pa 2 x 175 W, with a pulse repetition rate of 12.9 and 4.3 kHz, a pulse width of 40 ns and a spectral width of 1 and 3 GHz. Polarization was linear. The return flux was < 5 10 photons/m /s (Foy et al., 2000). Thus incoherent two-photon resonant absorption works, with a behavior consistent with models. But we do need lower powers at observatories ... 

Hodge VF, Johaimesson KH, Stetzenbach KJ (1996) Rhenium, molybdenum, and uranium in groundwater from the southern Great Basin, USA evidence for conservative behavior. Geochim Cosmochim Acta 60 3197-3214... 

Peninsula, Papua New Guinea (after Edwards et al. 1993). Open elhpses are data for samples collected from outcrop closed elhpses are data for samples collected from drill core. All points plot along the initial 5234 j =150 contom, indicating that all samples have maintained a primary marine uranium isotopic composition, consistent with closed-system behavior. Relatively yonng samples such as these are more likely to satisfy the closed-system assumption whereas older corals snch as those depicted in Figure 13 are not as likely to satisfy this assnmption. 

Gueniot B, Munier-Lamy C, Berthelin J (1988b) Geochemical behavior of Uranium in soils, part 11 Distribution of uranium in hydromorphic soils and soil sequences. Application for suificial prospecting. J Geochem Explor 31 39-55... 

Martin JM, Nijampurkar V, Salvation F (1978b) Uranium anti Thorium isotope behavior in estuarine systems. In Biogeochemistry of estuarine sediments. UNESCO, p 111-127 Mathieu D, Bemat M, Nahon D (1995) Short-lived U and Th isotope distribution in a tropical laterite derived from Granite (Pitinga river basin, Amazoitia, Brazil) application to assessment of weathering rate. Earth Planet Sci Lett 136 703-714... 

Toole J, Baxter MS, Thomson J (1987) The behavior of uranium isotopes with salinity change in three UK estuaries. Est Coast Shelf Sci 25 283-297... 

India (Borole et al. 1982) and the Forth estuary in the UK (Toole et al. 1987), nonconservative behavior of uranium was also demonstrated. In the Amazon estuary, uranium showed elevated concentrations compared to simple mixing (McKee et al. 1987). Release of uranium from bottom sediments on the shelf was suggested to be a source of dissolved (<0.4 im) uranium. However, subsequent studies in the Amazon also demonstrated that U removal (Fig. 3) occurred at salinities <12 (Swarzenski et al. 1995, Swarzenski et al. 2003). Overall, it was established that the behavior of U is highly variable examples have been found of conservative behavior as well as both additions and removal of U by interaction with sediments. 

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