Investigation on long-term daily load follow operation capability of soluble boron-free SMR

Abstract

Soluble boron-free reactors inherently have larger reactivity feedback than conventional pressurized water reactors during power transients. The purpose of this study is to verify the capability of the long-term load follow operation with only control rods for the soluble boron-free small modular reactors. The effects of the long-term load follow operation on burnup distribution, power distribution, reactivity balance and spatial xenon stability are investigated throughout the whole cycle.The reactivity balance results show that the control rod design of the soluble boron-free SMR successfully manages the reactivity changes introduced by power and xenon changes during the daily load follow operation. The spatial xenon stability analysis demonstrates that the SMR model has enough capability to suppress the axial and quadrant xenon oscillation without a second peak during the load follow operation. The load follow simulation results showed that safety parameters including peaking factor, axial offset and shutdown margin satisfy design limits.