URANIUM DIOXIDE MASS TRANSFER IN THE CENTRAL CHANNEL OF THE FUEL KERNEL OF A FUEL ELEMENT OF A SINGLE-ELEMENT ENERGY-GENERATING CHANNEL

The methods and computer program for calculating, as well as the computational results obtained, the remaining-life changes occurring in the profile of the central channel of the kernel of a fuel element in a single-element electricity generating channel because of uranium dioxide mass transfer, taking account of the redistribution of the fuel components and the effect of the spacers, are presented. It is shown that the measured and a priori computed profiles of the central channel are close after prolonged testing. It is shown that the superstoichiometric composition of the initial uranium dioxide with oxygen coefficient close to 2.003-2.005 shifts in time to the stoichiometric composition. This is due to the removal of oxygen outside the bounds of the fuel kernel. The calculations show that when uranium dioxide with substoichiometric composition is used or a perforated screen is introduced into the central channel the rate of the axial mass transfer of uranium dioxide is decreased by almost a factor of 2.