Improvement of the axial power distribution control capabilities in VVER-1000 reactors

This article describes an automatic reactor power control system for VVER-1000 reactor and reports simulation analysis results for a typical daily load follow operation. The asso- ciated reactor control algorithm is called ``mode Gʹʹ that uses a heavy-worth bank (H-bank) dedicated to axial power shape control and the light-gray banks (G-banks) for reactor power change and reactivity compensation. The simulation results for daily load follow operation in three burnup states of ®rst cycle illustrate that the load follow capability of VVER-1000 reactors using this algorithm will be improved.