Oxidation of lanthanum carbide and graphite targets

At ISOLDE, uranium carbide and graphite targets are irradiated for the purpose of studying nuclear physics. Today more than 300 radioactive and highly pyrophoric targets have been stored for more than 20 years, waiting to be treated. The oxidation of such targets would allow to stabilize these wastes. The aim of this study is to understand this oxidation reaction using macroscopic quantities of lanthanum carbides, since they have properties very close to those of uranium. To carry out this study, the oxidation reaction of lanthanum carbides and graphite pellets under a controlled flow of oxygen and under different temperatures was carried out. The reaction was followed by different analytical techniques such as mass tracking, RGA and XRD. The oxidation of the lanthanum carbide and graphite targets by oxygen could be totally done at temperatures above 850°C. The products of this oxidation are those desired, namely CO2 and lanthanum oxide. Optimal conditions were determined for this reaction and a good understanding of this oxidation reaction was obtained.