POWER PLANT AND WATER CLEANING METHOD FOR A ONCE-THROUGH WATER/STEAM CYCLE OF A POWER PLANT

A power plant with a water-steam-cycle includes a steam generator with a plurality of heating surfaces that carry a fluid and transfer heat to the fluid. The plurality of heating surfaces has an economizer for preheating the fluid and a fluidly connected evaporator for producing steam. A steam turbine receives the steam produced in the steam generator to generate power output. A condenser condenses steam from the steam turbine. The condenser has a hotwell as collection container for condensed steam or water. A polishing plant is arranged fluidly between the hotwell of the condenser and the economizer. A drain line interconnects an outlet of the economizer and the hotwell of the condenser. A fluid line interconnects the outlet of the economizer and the evaporator. The fluid line includes a syphon to hold back water in the economizer.