NUMERICAL SIMULATION OF MIXED OXIDE FUEL BURNUP TAKING ACCOUNT OF DOUBLE HETEROGENEITY

摘要

The results of a numerical simulation of the burnup of mixed oxide fuel in VVER-1000 talcing account of double heterogeneity are presented. The fuel consists of two different materials: a depleted uranium matrix with small amounts of plutonium and agglomerates consisting of particles with an elevated plutonium concentration. An important problem is taking double heterogeneity into account correctly, making it possible to evaluate the ratio of the energy release over the fuel-element pellet. Numerical results are obtained for the burnup distribution, energy release, and the concentrations of helium, krypton, and xenon over the radial zones of a fuel element depending on the average fuel burnup over the pellet. The MCU-REA program with the ORIMCU module for calculating burnup was used to perform the calculations.