LAUSR

The concept of annular fuel rods was initially studied in the 1950s, but researchers have expanded the investigations considerably from 2000 to improve the performance of nuclear power plants. Thus, aiming a probable replacement of the fuel assemblies of Angra II reactor, a PWR (Pressurised Water Reactor) type in operation in Brazil, this paper presents a neutronic comparison between the Typical Fuel Assembly (TFA) and the Annular Fuel Assemblies (AFAs). Five different AFA geometries are compared with a TFA to evaluate the influence in the criticality, neutron flux and the Doppler Coefficient of Reactivity. The Monte Carlo N-Particle Transport code, Version 6 (MCNP6), was used to calculate the neutronic parameters. The results present small variations among the simulated fuel assemblies, where the AFA with 11x11 fuel pins presents better agreement in relation to criticality and neutron flux values when compared with the TFA.