Sintering of nanocrystalline (U_1-xCe_x)O₂

The uranium plutonium mixed oxides (MOX) are used as fuel in sodium cooled fast reactors (SFR). Chemistry of cerium and plutonium is quite similar and very often cerium is considered to be a surrogate for plutonium. Hence, the studies on the U-Ce-O systems are of relevance to the fission reactor fuels. High density pellets of mixed actinide oxide fuels are usually fabricated through conventional powder metallurgical routes. These techniques involve process steps that include sintering at temperatures above 1873 K. Special care needs to be taken in order to ensure homogenization of the milled powder mixtures and the formation of a single phase solid solution product. Further these processes are energy and cost intensive. Hence an alternate route that is both cost and energy efficient is more desirable. Gel-combustion synthesis is one such alternate route for the synthesis of highly sinterable nuclear ceramics. The Indian Prototype Fast Breeder Reactor (PFBR), employs mixed oxides of uranium and plutonium with the compositions (U_1-xPu_x)O₂ (x = 0.22, 0.28) fabricated through conventional powder metallurgical route. Hence the sintering studies of the nanocrystalline (U_1-xCe_x)O₂ (x = 0.22,0.28) is relevant and is presented below