Bir Nükleer Santralin Soğutma Suyu Sıcaklığına Bağlı Enerji ve Ekserji Analizi

Abstract

The need for energy that has been rising with the developments in technology and industry around the world and in our country has moved the attention towards more efficient, clean, environmentally friendly, and sustainable systems for energy production. Nuclear power plants (NPP), alternative to fossil fuel-based power plants, are reliable systems that use nuclear fuel with low carbon and high energy density and can produce uninterrupted electricity. Power plants that depend on a heat source, including nuclear power plants, cannot completely convert the heat energy into usable work energy. It is possible to understand the interactions between the system and the surroundings by conducting energy and exergy analyses on these systems, and to increase the efficiency of the system by changing the environmental conditions. Exergy, based on the second law of thermodynamics, depends on the conditions of both the system and the environment (dead state) from which the cooling water is obtained. Therefore, the ambient temperature affects the efficiency of the system.

In this study, the energy and exergy analyses of a nuclear power plant (NPP) that may be constructed in the Black Sea region in our country due to energy needs were conducted based on the data available in the literature for the Bushehr power plant in Iran, which includes a VVER (Voda-Vodyanoi Energetichesky Reactor) type pressurized water reactor. The effect of the temperature of the cooling water entering the condenser in the NPP on the exergy efficiency of the system was calculated depending on the monthly change of the temperature of the seawater in Black Sea. As a result of these calculations, it was found that the percent energy efficiency of the NPP decreased from 34.19% to 33.58% as the temperature of seawater increased from the lowest 9.1 °C in March to the highest 24.7 °C in August. The increase in the temperature of seawater caused a decrease in the amount of total work produced from the turbines. As a result, the percent exergy efficiency decreased from 34.68% to 34.08%. Comparing the percent exergy and energy efficiencies calculated for the same month showed that the exergy efficiency was approximately 0.5% higher than the energy efficiency. The lowest exergy destruction and percent irreversibility obtained for the month of March, when the system works most efficiently and the temperature of seawater is the lowest, was determined as 1938.80 MW and 64.57%, respectively.