Optimal fuel management by maximizing the end-of-cycle effective multiplication factor

A new method has been devised to refuel light water reactors to attain optimum results. The new method first calculates the depletion of an acceptable pattern for reloading the core. Using the resulting end-of-cycle (EOC) core, the burnup and U-235 enrichments are redistributed respectively, by the Lagrange Multiplier Method, to maximize the EOC k/sub eff/ while meeting all safety constraints. By increasing the EOC k/sub eff/, U-235 can be removed from the beginning-of-cycle (BOC) core and still meet EOC reactivity (energy) requirements. The three Mile Island Unit-1 (TMI-1) PWR is used as the reference core for this optimization study. The project has been accomplished in four parts. Each part is described as follows: First, a new high-speed two-dimensional code, MCRAC, has been developed. Second, the EOC burnup is redistributed to determine the optimal EOC burnup and power distributions. Third, the EOC enrichment is redistributed to determine the optimal EOC enrichment distribution and define the optimal BOC enrichment distribution. Fourth, it has been demonstrated that all of the above methods are efficient and successful for reloading fuel to reduce the U-235 requirements for the core, while maintaining all other specifications unchanged