Mass transfer of uranium in primary circuits of nuclear power installations on contact of the UO2-based fuel with water coolant

The erosion of the UO2-based fuel composition in water primary coolant of nuclear power installations was simulated. The U species in the coolant and the trends in the U distribution between the coolant and surfaces of structural materials (12Cr18Ni10Ti stainless steel, PT-7 titanium alloy) were determined. The effect of the radiolysis products on the dissolution kinetics of UO2 particles in neutral and weakly alkaline aqueous media was revealed. The U transfer into the solution is determined by the concentration of oxidants. The maximal rate of dissolution of the ceramic fuel under the conditions simulating the real conditions was 5.0 × 10−8 g cm−2 day−1. In the process, the maximal U concentration in the solution can reach 100 μg dm−3.