Burnup Calculations with Time-Dependent Generalized Perturbation Theory

The application of generalized perturbation theory, both time dependent and static, to burnup problems is discussed. Simple analytical forms, applicable for many cases of interest, are derived for the time-dependent expressions. The influence of changes in Φ(E,r) during the cycle on the production of the plutonium isotopes is calculated for a typical liquid-metal fast breeder reactor case, using perturbation theory. Comparison of the results with direct calculations indicates that perturbation theory gives satisfactory accuracy for this problem.