The Research And Analysis On Thermal Economy Of Variable Conditions For Thermodynamic System Of A Nuclear Power Unit

In recent years,China advocates to adjust energy structure, and develop new energy and renewable energy. The development of the 3rd generation nuclear power technology has important significance for increasing the proportion of non fossil energy consumption,relieving the pressure of energy-saving and emission-reduction and achieving sustainable development. Studying on the thermal economy of conventional island system for nuclear power unit helps to understand thermal economy of unit variable condition and to provide theoretical basis for peaking operation of nuclear power unit. This paper takes a 1400 MW conventional island two loop thermal system for nuclear power unit as the research object,the main work finished is as follows:A universal model for calculation of thermal system of nuclear power plant has been deduced using matrix method. A generalized regenerative system is defined, the steam water separator is regarded as a kind of heat exchanger. Regenerative system of nuclear power unit is divided into 10 control volum. After establishing equations of that regenerative system, the physical meaning of each parameter is clear and the rules to fill the structure matrix,steam-extracting coefficient matrix,feed water enthalpy rise matrix and so on.The calculation results verifies the correctness of the model.In this paper,Thermal economy on different working conditions of heaters cutoff,shanges of new steam pressure,back pressure,reheat steam pressure and so on have been calculated based on heat balance method. The reasons for the changes of the results are analyzed in detail.In this paper,exergy loss and exergetic efficiency of components and process are analysed under various modes of work condition using exergy analysis. Compared the distribution exergy loss and exergetic efficiency of feed water heaters,steam condenser,moisture separator reheater and so on under various modes of work condition.