The solubilisation of Ru and U from condensation particles released b overheated nuclear fuel and maturated in air and in argon

Abstract

SummaryThe emission of uranium and ruthenium oxides from overheated nuclear fuel is a complex phenomenon which depends on fuel matrix, temperature, oxygen potential of the atmosphere in contact and on emission sequence. Furthermore, secondary annealing (“maturation”) reactions of aerosol particles in the gas phase, immediately after emission, strongly influence the properties of particles before their dispersion in the reactor containment building and/or in the environment. Maturation influences surface and bulk gradient composition, particle size, and, as a consequence, weathering rates in the environment. This paper describes how emission and maturation conditions may affect the solubility rates of condensation particles released by overheated U and Ru oxides mixtures, in small-scale laboratory simulations. It will be demonstrated that the presence of Ru decreases the solubilisation rate of U.