INVESTIGATION OF THE REACTION UO2+X+PUO2+C+N2 BY THERMOGRAVIMETRY

The kinetics of formation of uranium-plutonium nitride pellets by carbothermic reduction of uranium- and plutonium oxides under flowing nitrogen has been investigated using thermogravimetric techniques in the temperature range 1650-1870 K. The starting blends were prepared from powder material with different characteristics, and contained about 1 percent carbon in excess of the amount to obtain the stoichiometric composition. The reactions investigated were (a) the carbothermic synthesis under nitrogen of a low-carbon carbonitride containing free carbon and small amount of oxygen impurity and (b) the decarburization of the carbonitride under a N2-8 percent H2 gas mixture. This work was carried out within the frame work of the study for the fabrication of (U, Pu)N fuel using the direct pressing method.