A constant reactor-outlet-temperature control system for nuclear power plants

Most nuclear power plant designs involve the transmission of heat from the core of a nuclear reactor to the boiler of a steam plant by a gas or liquid coolant. A primary function of the power plant control system is to control the temperature of this coolant to provide the desired heat transfer rates and temperature levels in the boiler and reactor. The control system must also prevent transient excusions in the coolant temperature from exceeding the material and structural limitations of the power plant. Major obstacles to the control of transient excursions in coolant temperature are (1) the tendency of these temperature variations to be recirculated in the closed coolant loop, (2) the long transport lags associated with the coolant circulation, and (3) the large inherent time lags of thermometers measuring the coolant temperature.