Reactor control system for a nuclear power plant with drums

Purpose: To improve the availability of a reactor by controlling the fluid level in response to the reactor pressure when switching the speed of a recirculation pump to prevent the erroneous trip of the reactor. Constitution: When fluid level is largely varied when the speed of a recirculation pump is varied in a reactor for altering the speed intermittently, the level variation is restricted by utilizing the level change due to the pressure reducing drop or pressure increasing drop. When the level is controlled by three factors such as a fluid level, feedwater flow rate and vapor flow rate, the vapor flow rate is altered in advance to the level change, thereby improving the rapid response of the feedwater control system. (Aizawa, K.)