The Effect of Precipitation on Radionuclide Release from Used Fuel

Abstract

Solubility-limited dissolution models are often used to calculate source terms for the environmental assessment of used nuclear fuel disposal in geological vaults. In these models it is usually assumed that the solubility of the used-fuel matrix is constant. However, spatial inhomogeneities can produce solubility gradients and, hence, cause precipitation downstream from a dissolving used-fuel matrix. In this paper, the effect of precipitation on the used-fuel dissolution rate has been investigated. Precipitation of uranium-containing solids has been found to increase the dissolution rate of used fuel.