Study the neutronic feasibility of using Zr as an energy regulator instead of traditional methods

Abstract

The control of the reactor energy increases the reactor fuel cycle time. In this work, a new method has been investigated to control the reactor energy instead of traditional methods. SERPENT2 version 2.1.30 was used to investigate the possibility of using Zirconium rods as an energy regulator in the VVER-1000. Zirconium rods were used as water displacers. The effect of different Zr rod diameter on the infinite multiplication factor (k∞) of the reactor and the fuel concentration at different fuel burnup steps has been analyzed. Larger fuel pitches have been investigated to increase the Zr rod diameter. The main safety parameters such as the void volume reactivity coefficients, the Doppler reactivity coefficients and the Moderator temperature coefficient have been studied at different fuel pitch and different Zr rod diameter. A comparison between the effect of Zr rods and boric acid on the reactor reactivity proved the efficiency of using Zr rods as reactivity regulation.