THE OXIDATION OF URANIUM-CERIUM MONONITRIDE MICROSPHERES

The reaction of oxygen with UN and (U,Ce)N microspheres containing 15 and 30 mole % of cerium was studied in 6.6 kPa pressure of oxygen, und er non-isothermal heating conditions, using a thermobalance coupled to a gas chromatograph for evolved gas analysis. For uranium mononitride the final product was U3O8 with UO2 and U2N3 as intermediate products . However, for (U,Ce)N containing 15 mole % of cerium, the final produ ct of oxidation was MO2+x with sesqui-nitride as the intermediate prod uct. The (U,Ce)N microspheres with 30 mole % of cerium ignited during the reaction forming a mixture of M3O8 and MO2+x. The kinetic paramete rs were evaluated and the mechanism of the reaction was suggested to e xplain the catalytic action of cerium on the oxidation of nitride. (C) 1997 Elsevier Science S.A.