THE EFFECT OF OXYGEN IMPURITY ON THE CHARACTERISTICS OF URANIUM AND URANIUM PLUTONIUM MIXED NITRIDE FUELS

The effect of oxygen impurity on the typical characterisitics of UN and (U, Pu)N fuels was investigated. The oxygen content of the samples was adjusted to approximately 0.3, approximately 0.6 and approximately 1.0 wt%. It was confirmed from chemical, X-ray and ceramographic analyses that oxygen added to the nitrides existed in the oxide precipitates after sintering. While sinterability was not affected by oxygen content under the experimental condition, distinct decrease in the grain size with oxygen content was observed. Furthermore, the addition of approximately 1.0 wt% of oxygen impurity decreased the thermal conductivities of UN and (U, Pu)N by 9-10 and 12-13% at 1000 and 1500 K, respectively.