Low temperature decomposition of U(IV) and Th(IV) oxalates to nanograined oxide powders

Insights into the sonochemical synthesis and properties of salt-free intrinsic plutonium colloids

“…Similar nanograined architectures have been recently observed for UO 2 and ThO 2 oxides obtained by the calcination of U(IV) and Th(IV) oxalates at 600 °C24. A corresponding morphology can also be observed in a low resolution TEM image of ThO 2 employed in this work (Figure S3).…”

Kinetic study on the grain growth of PuO2 nanocrystals

“…14,15 The main differences between the wet and the dry oxalate decomposition are the lower temperature and the formation of spherical particles for the wet oxalate decomposition, [8][9][10] whereas the powders resulting from the dry decomposition maintain the platelet shape of the original oxalate. 7 The bulk modulus of spherical UO 2 nano-particles obtained by thermal decomposition of inorganic media 2 was measured to be 50% lower compared to the bulk. 16 The nanometric dimension of the particles enables as well to follow the growth of the crystallite as a function of the temperature by high-temperature X-ray diffraction (HT-XRD).…”

“…[1][2][3][4][5][6] More recently the actinide oxalates were used as the starting material for the synthesis of actinide dioxide nanopowders via thermal treatment. [7][8][9][10] The oxalate route offers several advantages: it is oen applied in the nuclear fuel cycle and therefore is state of the art in separation, 11 recycling of the actinide ions, 12 fuel production 13 or the reprocessing of spent fuel. 14,15 The main differences between the wet and the dry oxalate decomposition are the lower temperature and the formation of spherical particles for the wet oxalate decomposition, [8][9][10] whereas the powders resulting from the dry decomposition maintain the platelet shape of the original oxalate.…”

Speciation of residual carbon contained in UO2

“…The beam has a diameter equal to 2 µm. Contrary to what has been previously observed by Tyrpekl et al [14], the laser intensity was sufficiently low to avoid an oxidizing of UO 2 to U 3 O 8 or UO 3 compounds.…”