FEED WATER HEATING SYSTEM FOR NUCLEAR REACTOR

PURPOSE:To prevent the flowing of the drain into a condenser through an emergency drain pipe even if an emergency level control valve is erroneously opened due to its fault by providing a shutoff valve to the emergency drain pipe for discharging the drain in a drain tank in times of emergency by the condenser. CONSTITUTION:The drain in a drain tank 11 is not supplied to a condensate pipe 6, when a drain pump is stopped. Accordingly, the water level is raised by the drain accumulated in the tank 11, and a shutoff valve 19 is fully opened by the signal from a level switch 20. Consequently, the drain in the tank 11 is sent to a condenser 2 through an emergency drain pipe 17. A signal from a level transmitter 14 is sent to an emergency level control valve 18 through a level controller 15, hence the opening degree of the valve 18 is adjusted to keep a high water level, and the level in the tank 11 is controlled. As the valve 19 is fully opened in the normal operation, the drain does not flow into the condenser 2 through the pipe 17 even if the valve 18 is erroneously opened due to any fault, and the level in the tank 11 is never affected.