Thermal analysis of closed feedwater heaters in nuclear power plants

A model is introduced for the thermal analysis of closed feedwater heaters in which wet steam is extracted from the steam turbine (and piped into the heater). Where the fluid flowing through the steam turbine is wet steam, application of this model is of relevance to nuclear power plant diagnostics. At present, all feedwater heater calculations are performed by setting the stage moisture removal effectiveness, on the assumption that the mass flows and/or the enthalpy rates of the steam bled from the turbine are known values. Our model enables detection of multiple malfunctions, even where inaccurate readings may have been registered in the control room at an earlier point in time. Furthermore, there is no immediate need for on-site inspection, which is an important advantage in Boiling Water Reactor Power Plants where feedwater heaters are placed in high radiation dose areas.