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Vauchy R, Fouquet-Métivier P, Martin PM, Maillard C, Solinhac I, Guéneau C, Léorier C. New sample stage for characterizing radioactive materials by X-ray powder diffraction: application on five actinide dioxides ThO2, UO2, NpO2, PuO2 and AmO2. J Appl Crystallogr 2021. [DOI: 10.1107/s1600576721002235] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
A new sample stage for characterizing radioactive materials by X-ray powder diffraction was developed at the ATALANTE facility (CEA Marcoule, France) using a conventional (non-nuclearized) Bruker D8 goniometer mounted in Bragg–Brentano geometry. The setup consists of a removable, fully hermetic sample stage, with a 200 µm-thick beryllium window, that can be plugged onto a glove-box, allowing the sample to be introduced in an hermetic medium that also encapsulates the glove-box atmosphere throughout the analysis process. The whole setup is thus hermetically unplugged from the glove-box and positioned on the centre of the goniometer. No preliminary decontamination and/or decontainment of the sample is necessary. The device was developed to avoid an expensive and time-consuming nuclearization of the diffractometer while also keeping it easily accessible for maintenance. Ultimately, keeping the diffractometer out of a glove-box also limits the volume of the final nuclear wastes, and thus the removable sample stage is the only `active' part. X-ray diffraction results of two NIST standards LaB6 and α-Al2O3 as well as five actinide dioxides ThO2, UO2, NpO2, PuO2 and AmO2 are presented to show the efficiency of the setup.
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Vauchy R, Joly A, Valot C. Lattice thermal expansion of Pu1−yAmyO2−xplutonium–americium mixed oxides. J Appl Crystallogr 2017. [DOI: 10.1107/s1600576717014832] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Plutonium–americium mixed oxides, Pu1−yAmyO2−x, with various Am contents (y= 0.018, 0.077, 0.21, 0.49, 0.80 and 1.00) were studiedin situby high-temperature X-ray diffraction. In this study, the lattice thermal expansion of the six compounds subjected to heat treatments up to 1773 K under reconstituted air (N2+ 21% O2+ ∼5 vpm H2O) was investigated. The materials remained monophasic throughout the experiments and, depending upon the americium content, the lattice parameter of the face-centred cubic phase deviated from linear lattice expansion at elevated temperatures as a result of the progressive reduction of Am4+to Am3+.
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