Design of a simulated void-reactivity feedback in a boiling water reactor loop

The design and implementation of a simulated void-reactivity feedback in an experimental thermal-hydraulic loop meant for boiling water reactor (BWR)- dynamics studies is described. The void fraction in the loop is measured in real time and used as an input to a simulation that calculates the effect of void-reactivity on the reactor power. The resulting signals are used to control the power supplies of the loop. Advantages of this hybrid system in the study of BWR dynamics is that the complicated transfer functions relat ed to two-phase flow are realized physically while the relatively simple tr ansfer functions related to the nentronics are simulated.