... Clay Minerals Society Clay Extraction Chromatography ICP-MS Neptunium Non-isotopic Tracer Plutonium The studies mentioned above proved that Pu can be used as a non-isotopic yield tracer for determination of Np. 242 Pu has been used by Dai et al. ( 2015 ) and Qiao et al. ( 2013b...

.... , Kuczewski , B. , Kutscher , D. , Reich , T.Y. , Reich , T. , and Trautmann , N. ( 2008 ) Interaction of neptunium and plutonium with humic substances and kaolinite . Pp. 141 – 216 in: Migration of Actinides in the System Clay, Humic Substances, Aquifer ( C.M. Marquardt...

...Adam J. Williamson; Katherine Morris; Christopher Boothman; Kathy Dardenne; Gareth T.W. Law; Jonathan R. Lloyd Abstract Neptunium-237 will be present in radioactive wastes over extended time periods due to its long half-life (2.13 × 10 6 years). Understanding its behaviour under conditions relevant...

... materials, by virtue of their good retardation properties. Neptunium (Np) is one of the actinides which is considered in long-term scenarios due to its long-lived nuclide 237 Np ( t 1/2 = 2.1×10 6 y). Because neptunium sorption is heavily dependent on the experimental conditions, comparison of sorption data...

... , Swedish Nuclear Fuel and Waste Management Company . Foti S.C. Freiling E.C. ( 1964 ) The determination of the oxidation states of tracer uranium, neptunium and plutonium in aqueous media . Talanta , 11 , 385 – 392 . Ito M. Okamoto M. Shibata M. Sasaki Y...

... A.J. Triay I.R. . 1998 . A reactive transport model of Neptunium migration from the potential repository at Yucca Mountain . J. Hydrol. 209 : 251 – 280 . doi:10.1016/S0022-1694(98)00122-X Warren J.E. Root P.J. . 1963 . The behavior of naturally fractured reservoirs . Soc...

... short half-lives ( Table 1 ), but are highly mobile and bioavailable. They are present in HLW and have been released into the environment through reprocessing activities and accidents. The isotopes of uranium, plutonium and neptunium are highly radiotoxic and are present in HLW and ILW; together with Tc...

... neptunium pyrochlore I thank The Mineralogical Society for the invitation and honour of presenting the Hallimond Lecture. This is an undeserved, but much cherished honour, particularly as it brings me back to Cambridge, a place with a long tradition in the science of the subjects that I have...

... from a series of quantum-mechanical calculations in which the uranium end-member is pure studtite and the neptunium end-member is a theoretical Np-studtite structure with Np 6+ replacing all U 6+ atoms. Due to the limited number of cations in the unit cell (4, limited by the computational expense...

... and variance of the simulated percolation fluxes at the water table with (a and b) and without (c and d) considering the water retention parameter uncertainty. Transport of a conservative tracer, technetium ( 99 Tc), and a reactive tracer, neptunium ( 237 Np) was simulated for a scenario in which...

... for Np 5+ , the most important and interesting oxidation state for neptunium from a solid-state perspective. They set the b value at 0.37, and determined a value of R o of 2.036 Å, which provided bond-valence sums between 4.9 and 5.1 for most known structures. Given the inability to properly...

... such materials. Soddyite uranophane neptunium nuclear waste Yucca Mountain Geological disposal of nuclear waste poses a daunting range of scientific and engineering challenges ( Macfarlane and Ewing 2006 ). A repository should prevent a range of radionuclides with vastly different chemical...

.... , Brown , N.R. & Dietz , N.L. ( 1996 ): Contaminant uranium phases and leaching at the Femald site in Ohio . Environ. Sci. Tech . 30 , 81 – 88 . Burns , P.C. , Deely , K.M. & Skanthakumar , S. ( 2004 ): Neptunium incorporation into uranyl compounds that form...

[email protected] 16 11 2006 19 06 2006 © 2007 American Mineralogist 2007 Metaschoepite uranyl uranium nuclear waste geologic repository crystal structure neptunium Hexavalent U (uranyl) minerals occur in the oxidized zones of U deposits, where it is common for several uranyl...

... between the burn-up of the fuel and its detailed “mineralogy”? All of these questions can be repeated as we look beyond uranium to the crystal-chemistry and geochemistry of the transuranium elements, such as plutonium and neptunium. The journey has just begun. We thank David Sassani...

... for lengthy periods and thus improving the long-term performance of the repository. Here we discuss one very important radionuclide, 237 Np (half-life = 2.14 million years), and focus on mineralogical studies that probe the potential impact of uranyl minerals on neptunium mobility. Neptunium (Np), atomic...

... heated for one week at 150 °C in a gravity convection oven, and were allowed to cool slowly in the oven. Sprays of dark green needles approximately 600 μm in length formed during the reaction. Neptunium uranyl mineral uranophane nuclear waste crystal structure actinide T able 3...