J. Phys. IV France 118 (2004) 127-134
DOI: 10.1051/jp4:2004118015
Contribution of the synchrotron diffraction study of the oxidation of uranium dioxide at 250
C
G. Rousseau1, 2, 3, L. Desgranges1, J.C. Nièpce2, G. Baldinozzi3 and J.F. Bérar4
1 CEA Cadarache, DEC/S3C/LECMI Bât. 316, 13108 St. Paul-lez-Durance, France
2 LRRS, UMR 5613 CNRS-Université de Bourgogne, 9 Av. Alain Savary BP. 47870, 21078 Dijon, France
3 SPMS, UMR 8580 CNRS-École Centrale Paris, Grande voie des vignes, 92295 Châtenay-Malabry, France
4 D2AM CRG, CNRS, ESRF - Polygone Scientifique Louis Néel, 6 rue Jules Horowitz, 38000 Grenoble, France
Abstract
The structural evolution of UO
2 during its oxidation into U
3O
8 at 250
C in air was studied by in-situ synchrotron X-ray diffraction on the D2AM-CRG beamline at ESRF. The aim of this study is to
determine the phases which are likely to appear during a long term storage of used nuclear fuel. Our results are in disagreement
with the literature where the existence of the secondary cubic phase is not reported, and an
-U
3O
7 tetragonal phase (
) is also mentioned but definitely not observed. These previous interpretations are possibly due to a poor instrumental resolution,
inducing a sensible broadening of the diffraction peaks. Particularly, the fact that the instrumental resolution was unable
to resolve the splitting of the 111 diffraction peak, when UO
2 and U
4O
9 exist simultaneously, confirms the wrong phase attribution in the literature.
© EDP Sciences 2004