Abstract: [Objectives]　To address the issue of marine thermal pollution caused by the direct discharge of low-grade waste heat from nuclear power plants, it is imperative to explore efficient solutions to reduce thermal discharge loads. By systematically evaluating the characteristics of different types of waste heat sources and their potential of power generation, this study provides thermo-economic data basis for waste heat utilization in nuclear power plants. [Methods]　The characteristics of different types of low-grade waste heat in nuclear power plants are summarized, and different utilization methods of waste heat and their current development status are analyzed. Three types of power generation technologies suitable for this waste heat are introduced, and their thermo-economic performance and the recovery potential of different waste heat sources are comparatively analyzed through actual case studies. [Results]　The energy quality coefficient of the secondary loop condensate saturated water in nuclear power plants is the highest, showing the greatest potential for power generation utilization. The organic Rankine cycle (ORC) demonstrates optimal thermo-economic performance as a waste heat power generation solution, achieving the lowest levelized cost of electricity at $0.037 6/(kW⋅h), which is 84% and 78% lower than that of the ejector organic flash cycle (EOFC) and the Kalina cycle (KC), respectively. Moreover, ORC achieves a generation capacity of 462.2 kW, demonstrating good feasibility. Recovering waste heat from the low-pressure turbine exhaust can reduce thermal discharge by 360.3 MW, showing significant environmental benefits. [Conclusions]　Waste heat power generation technologies such as the ORC can significantly reduce thermal discharge loads into the sea, providing important references for low-grade waste heat utilization and thermal pollution reduction in China's nuclear power plants.

Key words: nuclear power, waste heat power generation, thermal pollution prevention and control, low-grade waste heat recovery, organic Rankine cycle (ORC), ejector organic flash cycle (EOFC), Kalina cycle (KC), thermo-economic feasibility analysis