Feedwater control device in nuclear reactors

Purpose: To stabilize transient water level for each of the power levels in a nuclear reactor by putting water level set points in the reactor under the program control as functions of time and reactor power for turbine trip or reactor scram. Constitution: A turbine trip signal and a reactor scram signal are inputted into an OR circuit, the output of which is put to ON by the generation of either one of the signals. by the ON signal from the OR circuit, a timer and a relay are started and, while on the other hand, detection for the reactor power by the logic circuit is interrupted. The output from the timer is introduced into a function generator, from which an optional level setting change signal is issued as the function of time based on predetermined data. Then, by introducing the signal output by way of the relay, the water level set point is changed. As the result, more stable control with less unnecessary controls as compared with usual control by uni-meaning set point change can be obtained. (Seki, T.)