Oxidation-enhanced emission of ruthenium from nuclear fuel

In the course of a nine-day release by the Chernobyl reactor in April–May 1986, ruthenium was considered to have been emitted at the same rate as other refractory elements. In fact, there are indications that the release was more important than previously estimated and lasted for tens of days because of oxidation of Ru into volatile forms. This paper demonstrates that, when put in contact with air, small uranium oxide particles can release 100% of radioruthenium at temperatures of the order of 1000 °C.