Load control system for nuclear power plant

Abstract

A load control system for a boiling water reactor power plant. A recirculating pump speed demand signal and a total steam flow demand signal are derived on the basis of combination of a first control signalproduced in accordance with a power difference signal representative of difference between an actual value of an output power of an electric generator and a set value for the generator output and a second control signal produced in accordance with a pressure difference signal representative of difference between an actually measured value of the reactor pressure and a set value therefor. Speed of a recirculating pump is controlled in dependence on the recirculating pump speed demand signal, while opening degrees of a governor valve and a bypass valve of a turbine are controlled in accordance with the total steam flow demand signal. The recirculating pump speed demand signal and the total steam flow demand signal are derived by combining the first or the second control signal which has been regulated through gain elements. Further, the power difference signal is added to the pressure difference signal for modifying the set point for the reactor pressure.