Nuclear power plant facility

In the present invention, loads on a condensate filtering device (differential pressure break or the like) and corrosion products newly formed in a heater drain system of a BWR-type power plant are reduced. Namely, an oxygen injection device is disposed to a drain line for introducing drains from a feedwater heater to a condensator for controlling a dissolved oxygen concentration in the drain line to a predetermined level. Alternatively, a control valve to be opened and closed depending on the dissolved oxygen concentration in the drain line is disposed, instead of the oxygen injection device, to a bent line for introducing incondensible gases from the feedwater heater to the condensator. Alternatively, a control valve to be opened and closed depending on the pressure of the feedwater heater is disposed to the bent line instead of the oxygen injection device. With such a constitution, since dissolved oxygen in the heater drain water can be controlled by the injection of oxygen into the heater drain or by the control of the amount of the gases introduced to the bent line, crystal forms of oxygen can be changed into a form that can easily be processed in the condensate filtering device. As a result, generation of corrosion products can be suppressed. (I.S.)