Actinide Oxidation State and O/M Ratio in Hypostoichiometric Uranium–Plutonium–Americium U0.750Pu0.246Am0.004O2–x Mixed Oxides
| Autor: | Anne-Charlotte Robisson, Philippe Martin, Andreas C. Scheinost, Florent Lebreton, Romain Vauchy, Laurence Aufore, Renaud C. Belin |
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| Přispěvatelé: | CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Département d'Etudes des Combustibles (DEC), Helmholtz-Zentrum Dresden-Rossendorf (HZDR), The Global Actinide Cycle International Demonstration (GACID) project connecting the Commissariat à l’Energie Atomique et aux énergies alternatives (France), the Department Of Energy (U.S.A.), and the Japan Atomic Energy Agency (Japan) is also to be acknowledged for financial support., The authors would also like to acknowledge the European Synchrotron Radiation Facility (ESRF, Grenoble, France) |
| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
X-ray absorption spectroscopy Nuclear fuel Chemistry Analytical chemistry chemistry.chemical_element Americium [CHIM.MATE]Chemical Sciences/Material chemistry 02 engineering and technology Actinide Uranium 021001 nanoscience & nanotechnology 01 natural sciences 7. Clean energy Plutonium Inorganic Chemistry Oxidation state 0103 physical sciences [CHIM.CRIS]Chemical Sciences/Cristallography [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] Partial oxidation Physical and Theoretical Chemistry 0210 nano-technology Nuclear chemistry |
| Zdroj: | Inorganic Chemistry Inorganic Chemistry, 2016, 55 (5), pp.2123-2132. ⟨10.1021/acs.inorgchem.5b02533⟩ Inorganic Chemistry, American Chemical Society, 2016, 55 (5), pp.2123-2132. ⟨10.1021/acs.inorgchem.5b02533⟩ |
| ISSN: | 1520-510X 0020-1669 |
| DOI: | 10.1021/acs.inorgchem.5b02533 |
| Popis: | International audience; Innovative americium-bearing uranium–plutonium mixed oxides U$_{1–y}$Pu$_y$O$_{2–x}$ are envisioned as nuclear fuel for sodium-cooled fast neutron reactors (SFRs). The oxygen-to-metal (O/M) ratio, directly related to the oxidation state of cations, affects many of the fuel properties. Thus, a thorough knowledge of its variation with the sintering conditions is essential. The aim of this work is to follow the oxidation state of uranium, plutonium, and americium, and so the O/M ratio, in U$_{0.750}$Pu$_{0.246}$Am$_{0.004}$O$_{2-x}$ samples sintered for 4 h at 2023 K in various Ar + 5% H$_2$ + z vpm H$_2$O (z = ∼15, ∼90, and ∼200) gas mixtures. The O/M ratios were determined by gravimetry, XAS, and XRD and evidenced a partial oxidation of the samples at room temperature. Finally, by comparing XANES and EXAFS results to that of a previous study, we demonstrate that the presence of uranium does not influence the interactions between americium and plutonium and that the differences in the O/M ratio between the investigated conditions is controlled by the reduction of plutonium. We also discuss the role of the homogeneity of cation distribution, as determined by EPMA, on the mechanisms involved in the reduction process. |
| Databáze: | OpenAIRE |
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