Abstract
The present paper examines thorium as a fertile material in combination with 233U or plutonium, accordingly two types of fuel (Th,Pu)N and (Th,233U)N in addition to the traditional MOX fuel are proposed as fuel used for a small modular fast reactor cooled by sodium (SMFR). Monte Carlo computer code is designed to optimize and analyze the characteristic of the reactor under different fuel types. Several parameters such as reactor multiplication factor, cycle length, discharge fuel burnup (Mwd/T) and number of neutrons released per fission are calculated for every fuel types. Isotopic transmutation through the entire fuel cycle is evaluated and analyzed. Safety and kinetic parameters at beginning (BOC) and end of cycle (EOC) for each fuel type are calculated. Power mapping distributions are calculated and analyzed through different core intervals. Control rods worth required to control the reactivity are determined at BOC and EOC for all fuel types. Multiplication factor for the present model was compared with developed homogeneous model for MOX fuel with differences of 203 pcm between the two models.