Abstract: A power plant includes a steam generator, a turbine driven by steam generated by the steam generator, a condenser which cools the steam discharged from the turbine to form condensate water by using seawater, a condensate water pipe which supplies the condensate water from the condenser to the steam generator, at least one seawater leak detection device which is included in the condensate water pipe and measures water quality of the condensate water to detect a leak of seawater in the condenser, an attemperator spray which connects to the condensate water pipe to be supplied with the condensate water from a connecting point where the attemperator spray connects to the condensate water pipe, and sprays the condensate water to the steam inside the condenser, and a pipe which diverges from the condensate water pipe and supplies the condensate water to the steam generator, wherein if the seawater leak detection device detects a leak of the seawater in the condenser, the power plant stops pouring the condensate wat