Research on Cold End Optimization of Water Supply Mode of Expanded Unit System of Circulating Water System in Coastal Nuclear Power Plant

A typical northern nuclear power plant and a typical southern nuclear power plant are selected to optimize the cold end of the circulating water system with one machine and two pumps in an expanded unit system. And study the optimal operation mode of the circulating pump and the cold end configuration scheme with the minimum annual cost in this water supply mode. It is discussed how to combine the site conditions of the nuclear power plant, the price of raw materials and the main cold-end equipment of the steam turbine, the cost of the main structures of the water supply and drainage system and the related annual operating costs, power generation income and other factors, to seek the optimal solution through economic and technical comparison of multiple schemes. That is to select the optimal matching combination scheme of the configuration of the cooling water system such as the configuration scheme of the low-pressure cylinder of the steam turbine, the area of the condenser, the flow rate of the cooling water pump, and the cooling water pipe trench, and determine the economical and reasonable design parameters of the equipment at the cold end. By comparing the cold end optimization results of the constant speed scheme of 1 machine with 2 pumps, the frequency conversion scheme of 1 machine with 2 pumps and the expansion unit system scheme of 1 machine with 2 pumps, the frequency conversion scheme of 1 machine with 2 pumps is superior in terms of technology and economy and has a great advantage for the northern site. For the southern site, due to the higher water temperature and smaller variation, the advantage is less.