The Chernobyl pilot site project: Isolation and microscopic characterisation of fuel particles.
Actes du congrès ECORAD, 3-7 sept 2001, Aix en Provence, France
Radioprotection - Colloques, volume 37, C1-1055/ C1-1060.
A method of fuel particles separation from contaminated soil samples in heavy liquid was developed. Numerous particles have been isolated and characterised by Scanning Electron Microscopy. 14 years after Chernobyl accident 52% of Cs, 70% of Eu and Sr and 65% of Am still are associated with fuel particles. Hence the source term is mainly represented by fuel particles with a mean diameter of 4.17 µm. The source term consist of 2 types of particles: UO and ZrUO. Zr-U-O fuel particles account for 74% of the studied particles and showed much higher stability. Therefore the description of Chernobyl source term weathering requires 2 dissolution laws: a first one concerning UO particles with a higher dissolution constant and a second one with a low dissolution constant describing Zr-U-O dissolution.