FEEDWATER CONTROL SYSTEM FOR STEAM GENERATOR OF NUCLEAR POWER PLANT, CAPABLE OF REDUCING POSSIBILITY OF REACTOR STOPPAGE BY PREVENTING OVERSHOOT OF WATER LEVEL OF STEAM GENERATOR, AND CONTROL METHOD THEREOF

摘要

PURPOSE: A feedwater control system and a control method thereof are provided to reduce the possibility of reactor stoppage caused due to a high water level, by preventing an overshoot of water level of a steam generator. CONSTITUTION: A feedwater control system comprises a sensing unit(10) and a control unit(20). The sensing unit includes a flow rate error signal generating unit(11) and a water level correction error signal generating unit(15). The flow rate error signal generating unit generates a flow rate error signal(11c) corresponding to the difference between a steam flow rate signal(11a) corresponding to the flow rate of steam discharged from a steam generator and a feedwater flow rate signal(11b) corresponding to the flow rate of feedwater flowing into the steam generator. The water level correction error signal generating unit generates a water level correction error signal corresponding to the sum of a water level error signal and the flow rate error signal. The water level error signal corresponds to the difference between a water level measurement signal(15a) corresponding to the water level in the steam generator and a water level set signal(15b) corresponding to the preset water level in the steam generator. The control unit includes a proportional integral circuit(21), and controls at least one of a main feedwater pump(3), a main feedwater control valve(5), and a downcomer control valve(7) in accordance with the flow rate request signal processed through the proportional integral circuit.