Irregularity of plutonium isotopic composition of the BREST-OD-300 initial load

Abstract

This article is dedicated observation of irregularity of plutonium isotopic composition of the BREST-OD-300 initial load. The purpose of the research is to study the effect of the plutonium isotopic composition in the nitride fuel of the BREST–OD-300 reactor core starting load on the reactivity reserve. The calculations is creating by writing simplified three-dimensional geometry of the BREST-OD-300 reactor in software package “SERPENT”. There are five options in the fuel assemblies locations are considered with different cases of using the plutonium isotopic composition with deviations for some isotopes. Calculations have shown that the deviation of the plutonium isotope composition from the design values of the fuel loading of the BREST-OD-300 reactor does not affect the stability of reactivity during fuel burnout within the effective fraction of delayed neutrons. In the course of the research, changes in the effective multiplication coefficient are obtained over five years of reactor operation. The value of this indicator does not depend much on the plutonium deviation in the considered variations in the arrangement of fuel assemblies in the reactor core.