FEEDWATER HEATER DRAIN PUMP UP SYSTEM

PURPOSE:To prevent the damage of drain pumps by connecting a drain tank to plural drain pumps by drain tank downcast pipes, and providing condensate filling pipes for filling low temperature condensate from a condensate pipe into the drain tank downcast pipes. CONSTITUTION:Drain from a drain tank 12 is extracted by drain tank downcast pipes 17A 17B connected to drain pumps 15A, 15B in operation, and condensate is filled into the drain by condensate filling pipes 18A, 18B branched from the exit of a low pressure feedwater heater 6. Since the drain of constantly reduced temperature flows in the drain downcast pipes on the upstream side of the drain pumps 15A, 15B in operation and there is no drain holdup part, the generation of drain flash is prevented even at the time of transient operation when the pressure in the drain tank is suddenly lowered. Also, since a drain tank downcast pipe 17C on the upstream side of a drain pump 15C in the stop state is completely separated from the other drain downcast pipes 17A, 17B, even if drain flash is generated, generated bubbles escape going up to the drain tank 12.