Nuclear power plant control system

Purpose: To effectively transfer the operation of a nuclear power plant including a bwr type reactor to single load operation in the station with no increase in the neutron flux and water level in the reactor by the combined use of recycle pump trip and feedwater pump trip. Method: Upon rapid load decrease in a turbine generator, at least one of usually operated feedwater pumps and a recycle pump are tripped and the starting for a stand-by feedwater pump is inhibited. This rapidly decreases the recycling flow rate to thereby lower the neutron flux before generation of pressure increase and also decreases the feedwater flow rate to thereby suppress the increase in the water level due to increase in voids, whereby the operation is smoothly transferred to the single load operation in the station. (Horiuchi, T.)