Feedwater control device in nuclear reactors

Purpose: To maintain the reactor water level within a predetermined range automatically and prevent the reduction of the reactor water purity. Constitution: In the case of accidents leading to the reduction of the reactor water level in a nuclear power plant, a reactor core isolation cooling system (RCIC) pump and an emergency core cooling system (ECCS) pump are automatically started by a water level low signal from a reactor water level detector. After the recovery of the reactor water level, a feedwater pump is started by using condensates from a condensator as a water source, and reactor water level, reactor pressure, feedwater flowrate and feedwater pump exhaust pressure are inputted into a feedwater control system, and the instruction for the opening degree is given to a feedwater flowrate control valve by the output from the device such that the reactor water level rises within a predetermined range to control the reactor water level. This enables to mitigate the operator's works after the actuation of ECCS and maintain the safety reactor water level. (Takahashi, M.)