Development of the VVER core loading optimization system

The optimization procedures previously applied to Western type PWRs are being used for the first time to optimize the VVER 440 nuclear power plant (NPP)—Dukovany, and VVER 1000—NPP Temelin in the Czech Republic. The objective of the calculation is to minimize fuel cost while preserving all the safety constraints and margins. Optimization with burnable poisons (BP) is simplified by reloading the core in two steps; first, by optimum fuel placement using the Haling Power Distribution (HPD), and second, by optimum placement of burnable poisons to meet the safety constraints. This two-step single cycle optimization method can be extended to the multiple cycle level. Application to the VVER reactors involves applying a hexagonal geometry core analysis model. A program has been initiated to develop a similar multi-cycle optimization system for the VVER reactors between the Penn State University and SKODA in the Czech Republic. This research has been successful in developing loading patterns for cycles 2–4 of the Temelin NPP. The package, which was developed during this research, can be applied to any VVER reactors to optimize the core loading.