Directions for Increasing Thermal Efficiency of an NPP with PWR

Abstract

The construction and operation of nuclear power plants are characterized by significant capital costs associated with ensuring compliance with stringent nuclear safety requirements. To ensure a low estimated cost of electricity generated at nuclear power plants, it is especially important to increase their efficiency, which depends on the thermal efficiency of the turbine unit. Based on the criterion of economic efficiency, directions for increasing the thermal efficiency of nuclear power plants with pressurized water reactors (PWR) have been studied: increasing the fresh steam pressure, reducing the steam pressure in the condenser, optimizing the structure and parameters of the second circuit, and improving the efficiency of the turbine flow parts. Significant economic losses are caused by the use of a circulating technical water-supply system provided for at all designed nuclear power plants (according to Article 60 of the Water Code of the Russian Federation). It is noted that the ban on the use of direct-flow water supply systems contradicts the world experience of creating nuclear power plants. The difference in the efficiency of cooling systems of two types is clearly shown by the example of the design indicators of the Leningrad NPP-2 (LNPP-2) and the Tianwan NPP (power unit nos. 7, 8), which use identical reactor systems (RS) but different turbine units and technical water supply systems, which determines the difference in electrical power (up to 66 MW). Using data from the PRIS (power reactor information system) information system on power reactors around the world and the results of calculations by turbine construction companies, the level of thermal efficiency of low-speed turbines abroad, achieved through comprehensive optimization of technical solutions, was assessed. The reserves for increasing the economic efficiency of domestic nuclear power plants with PWR have been identified. It was noted that foreign companies do not stop working to improve the performance of the flow part of low-speed turbine units: models have been created with a last-stage blade length of 1905 mm. According to estimates, the total economic effect from increasing the efficiency of nuclear power plants when implementing all of the above measures, expressed through allowable additional investments, is 14 billion rubles, which is comparable to the cost of supplying all the key equipment of the power unit’s turbine room.