Thermal Economical Analysis Of The Secondary Circuit Piping System In PWR Nuclear Power Plant

The PWR nuclear power unit is a main type of nuclear power units at home andabroad, and its thermal economic property of secondary circuit system is related tothe benefit of the nuclear power plant. However，it is necessary to know the thermalefficiency of the pipeline influence factors, because it can get the way to reduce heatloss of the nuclear power plant pipeline. Moreover, comparative analysis of the PWRnuclear power plant piping thermal efficiency and the whole unit thermal economicproperty is helpful to analyse accurately the economic efficiency change mechanismof the secondary circuit thermal system.Firstly, the heat balance method has been researched according to thecomplexity of thermodynamic system of PWR nuclear power plant secondary circuitin this paper. Moreover, the computing formula of piping thermal efficiency andvarious kinds of piping thermal losses were introduced based on the definition ofpiping thermal efficiency. Aiming at the problem that some factors affecting pipingthermal efficiency also affected steam power transition system cycle thermalefficiency and the whole plant thermal efficiency of PWR nuclear power plant, itwas analyzed that the influence of the change of these factors affecting pipingthermal efficiency on steam power transition system cycle thermal efficiency and thewhole plant thermal efficiency of PWR nuclear power plant. And then taking an990MW nuclear power plant for example, the influence of leaking steam throughdrain valve of main stream pipe, auxiliary steam, radiation thermal loss of mainsteam pipe, blowdown from steam generator and all that on piping thermal efficiency,steam power transition system cycle thermal efficiency and the whole plant thermalefficiency were analyzed by calculating. Finally, according to steam generator’sblowdown system with the regenerative heat exchanger in PWR nuclear power plant,under the condition of steam generator’s blowdown capacity and parameters are fixed, the influence of condensed water ratio and recovery heat pattern on the cyclethermal efficiency, the secondary circuit piping thermal efficiency and the wholeplant thermal efficiency are respectively calculated. The work done in this paper isimportant to further reduce the cost of electricity and improve efficiency ofeconomic operation in PWR nuclear power plant.