Approach to equilibrium fuelling scheme of 500 MWe PFBR based on 3-D core burnup modeling

Approach to equilibrium fuelling scheme of 500 MWe prototype fast breeder reactor (PFBR) has been predicted using detailed 3-D core burnup modeling. Equilibrium is reached after two cycles of 180 effective full power days (efpd) each. One-third core is refueled every time in a repeatable scatter load scheme after every 3 cycles. Considering the constraints of linear heat rating (LHR) on fuel and blanket pins it is found that the nominal core achieves full power only in mid-cycle. A novel interpolation scheme is used to find the peak LHR in any axial section of a fuel/blanket sub-assembly. Breeding ratio is adequate for self-sufficient Pu generation in a closed fuel cycle with Pu from axial blankets and two rings of radial blanket sub-assemblies.