Dissolution Kinetics of Chernobyl Fuel Particles: I. Dissolution of Fuel Particles of Various Genesis in Model Experiments.

Kashparov V.A., Protsak V.P., Peres J.M. , Ahamdach N., Yoschenko V.I., Zvarich S.I. and Pazukhin Radiochemistry, Vol. 42, No. 6, 592-600

The dissolution kinetics of fuel particles obtained by mechanical crushing of the real irradiated Chernobyl fuel and by its oxidation in air at 670 K for 1-21 h was studied in relation to the solution acidity (pH 4-9.2). Oxidation is accompanied by cracking of the particles surface, which increases the true surface area and accelerates dissolution as compared to the nonoxidized particles. The rate of fuel particles dissolution increases in acidic and basic solution. The obtained parameters of the dissolution rate of the nonoxidized and oxidized fuel particles (UO2+x) in solutions of various acidities can be used as limiting estimates for predicting the evolution of the radiological situation in the vicinity of the Chernobyl NPP and the hypothetical radiation accidents with ejection of irradiated nuclear fuel particles. If necessary, appropriate additives can be used to adjust the acidity of the medium and efficiently decelerate the particle dissolution in the natural media, transfer of radionuclides to mobile forms, and their involvement in biogenic migration and migration to ground and surface waters.