Comparative XRPD and XAS study of the impact of the synthesis process on the electronic and structural environments of uranium–americium mixed oxides

Uranium-americium mixed oxides are potential compounds to reduce americium inventory in nuclear waste via a partitioning and transmutation strategy. A thorough assessment of the oxygen-to-metal ratio is paramount in such materials as it determines the important underlying electronic structure and phase relations, affecting both thermal conductivity of the material and its interaction with the cladding and coolant. In 2011, various XAS experiments on U1 xAmxO2±δ samples prepared by different synthesis methods have reported contradictory results on the charge distribution of U and Am. This work alleviates this discrepancy. The XAS results confirm that, independently of the synthesis process, the reductive sintering of U1 xAmxO2±δ leads to the formation of similar fluorite solid solution indicating the presence of Am+III and U+V in equimolar proportions.

PRIEUR Damien;  LEBRETON F.;  MARTIN Philippe;  CAISSO Marie;  BUTZBACH R.;  SOMERS Joseph;  DELAHAYE Thibaud; 

2015-07-28

ACADEMIC PRESS INC ELSEVIER SCIENCE

JRC91103

0022-4596,   

http://ac.els-cdn.com/S0022459615300049/1-s2.0-S0022459615300049-main.pdf?_tid=16deb8f4-2abf-11e5-b347-00000aab0f27&acdnat=1436943771_eef6e8e0b2ab8010beb41868aed760ef,    https://publications.jrc.ec.europa.eu/repository/handle/JRC91103,   

10.1016/j.jssc.2015.03.037,