Preliminary Neutronics Calculations for Conversion of the Tehran Research Reactor Core from Heu to Leu Fuel

The 5-MW highly enriched uranium (HEU)-fueled Tehran Research Reactor is considered for conversion to high-density, low-enriched uranium (LEU) fuel. A preliminary neutronics calculation is performed as part of the conversion goal. In this study, two cores are considered: the HEU reference core and a proposed LEU core similar to the reference core, using standardized U₃Si₂ plates with the option of different ²³⁵U loadings. Various possibilities are investigated for the conversion of HEU to LEU fuel elements with 20% enriched ²³⁵U loadings of 207 to 297 g ²³⁵U/element. For the same equilibrium cycle length, the fuels are compared for flux, power distribution, burnup, and reactivity.