Kinetic Behavior of Steam Void in Boiling Water Reactor

In this paper, a zero power reactor simulator and thermodynamic-hydrodynamic coolant loops were used to investigate BWR dynamics. The instability which appeared in thermodynamic and hydrodynamic loops in natural circulation condition is the most noticeable phenomenon. To investigate the instability, we operated the boiling loops only as the first step. Combining the zero power reactor simulator and thermodynamic-hydrodynamic loops in a closed form by use of an electric capacitor type of void fraction detecting device, we obtained satisfactory results in BWR simulation. Effects of void coefficient of reactivity on the whole BWR dynamics were investigated, also the influences of the coolant circulation condition were investigated. From these experimental results, it was concluded that the properties of power-void feedback transfer function have the predominant effects on the overall reactor dynamics. So, we investigated further the power-void transfer function and compared it with the theoretical transfer function. We proceeded further the theoretical approaches to understand the interesting tendencies which appeared in experimental power-void transfer function.