Modeling and Simulation of Deaerator in Nuclear Power Plant

Different deaerators have different structures, and the intensities of deaerating are different. But the deaerator models without considering the structure couldn’t show these aspects. In order to ensure the accuracy of simulation results, concrete structure of the deaerator should be taken into consideration. This paper carried out a mathematical model of horizontal type deaerator with constant nozzles and trays in nuclear power plants. It was built based on the structure of the segmentation deaerators and the process of heat transferring. This paper calculated the vapors condensation rate, it was based on heat transfer coefficient of direct contact condensation, and the heat transfer area of water film when working conditions were corresponding to the empirical formulas. While the working conditions were beyond the limits of empirical formulas, this paper would build models by conservation of energy, so the model could work under any working conditions. These models were installed in the simulation system of Qinshan Phase II., and were tested under variable power and accidental conditions. The testing results show that the models could fit for different steady working conditions. Compared with the outputs and the actual operating data, the error was small. Under the conditions of variable power and turbine tripping, changing of the parameters have the same trend curve with the actual operating data. Because of taking the concrete structure into consideration, these models can be performed better of the specific characteristics of the horizontal type deaerators with constant nozzles and trays in nuclear power plants, therefore the results are more accurate than the models without considering the structure.