Structural Investigation of (U0.7Pu0.3)O2-x Mixed Oxides

Uranium-plutonium mixed oxide containing 30% of PuO2 is a candidate fuel for several fast neutron and accelerator driven reactor systems. In this work, a detailed structural investigation on sol-gel synthesized stoichiometric U0.7Pu0.3O2.00 and substoichiometric U0.7Pu0.3O2-x, using X-ray diffraction (XRD), oxygen 17 magic angle spinning nuclear magnetic resonance (17O MAS-NMR) and extended X-ray absorption fine structure (EXAFS) spectroscopy is described. As observed by XRD, U0.7Pu0.3O2.00 is monophasic with a lattice parameter in good agreement with the Vegard’s law while the U0.7Pu0.3O2-x material is biphasic. Solid solution ideality in terms of a random distribution of metal atoms is proven for U0.7Pu0.3O2.00 with 17O MAS-NMR. X-ray absorption near-edge spectroscopy (XANES) confirmed the presence of plutonium (III) in U0.7Pu0.3O2-x. EXAFS investigations indicate a similar local structure around both cations, and comparison with XRD indicates a close similarity between uranium and plutonium local structures and the long range ordering.

VIGIER Jean-Francois;  MARTIN Philippe;  MARTEL Laura;  PRIEUR Damien;  SCHEINOST A.C.;  SOMERS Joseph; 

2015-07-14

AMER CHEMICAL SOC

JRC94813

0020-1669,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC94813,   

10.1021/acs.inorgchem.5b00392,