Development of an optimum long-term refueling strategy for Moltex stable salt reactor

An optimum long-term refueling strategy was developed for Moltex Stable Salt Reactors to minimize fuel cycle cost. The refueling strategy is based on the beginning-of-life (BOL) core that approximately represents the equilibrium cycle core configuration determined through a stochastic optimization method to minimize the radial power peaking. An optimum refueling sequence for the BOL core was identified until all the assemblies were replaced once, and it was repeatedly applied to the subsequent long-term operation. The effectiveness was demonstrated through long-term refueling simulations about 30 years of reactor operation. This optimal refueling sequence almost doubles the long-term average cycle length compared to the previous refueling strategies while satisfying the radiation damage limit. Sensitivity studies showed that the refueling sequence remains effective even when the number of enrichment zones is reduced significantly in the BOL core. This suggests that the developed refueling strategy is robust and adaptable to various initial core configurations.