Dissolution kinetics of particles of irradiated Chernobyl nuclear fuel: influence of pH and oxidation state on the release of radionuclides in the contaminated soil of Chernobyl

摘要

The radioactive contamination in the exclusion Chernobyl zone is mainly due to fuel particles present on the ground. Dissolution of these particles causes leaching of radionuclides to increase with time. The kinetics of dissolution of Chernobyl fuel particles were determined in solutions of different acidities, using material obtained by crushing actual irradiated Chernobyl fuel and by its oxidation for 1-21 h in air at a temperature of 670 K. Oxidation results in superficial cracking of the particles and an increase in their surface area and, therefore, higher dissolution rates for such particles than for non-oxidised ones. Dissolution rate of fuel particles increases in acid and alkaline mediums. The dissolution rates obtained for non-oxidised and oxidised fuel particles (UO2+x) in solutions of different acidities call be used as a basis for narrowing the scope of assessments for prognosis of changes in the radiological situation in the Chernobyl zone. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 20]