Techno-Economic analysis of alternative power cycles for Light-Water small modular reactors

Rankine (steam) cycle traditionally has been the exclusive energy conversion system (the secondary side) for nuclear power plants based on light-water reactors (the primary side). In an effort to improve the economics of nuclear as a clean, sustainable energy source, various small modular reactor designs have been developed and some have been scheduled to deploy at the end of this decade. In this work, technoeconomic analysis is conducted for three alternative power cycles for the light-water small modular reactor by NuScale Power, which include a regenerative reheat Rankine cycle, a transcritical ethanol cycle and a recompression supercritical CO2 cycle. The results have shown the baseline regenerative Rankine cycle is a good fit for the current small modular reactor due to its attractive cycle efficiency (31.2%), low cost and relatively simple design. Using the selected first-order cost models, the costs for the major power cycle components including turbines, compressors, pumps, and heat exchangers, as well as the levelized cost of electricity for each cycle are estimated. The results show both the regenerative reheat Rankine cycle and transcritical ethanol cycle would provide higher cycle efficiencies (33.1% and 33.9%) and a lower levelized cost of electricity (5.14% and 4.96% reduction from the baseline, respectively), while the recompression supercritical CO2 cycle has a lower thermal efficiency (29.8%) while a higher levelized cost of electricity (21.8% increase from the baseline). As the result, the recompression supercritical CO2 cycle is not suitable as the energy conversion system for light-water small modular reactors. HIGHLIGHTS Technoeconomic analysis of three alternative power cycles for a small modular light-water reactor is conducted. Cost models for major components are comparatively selected for calculating levelized cost of electricity for each alternative power cycle. Supercritical CO2 cycle is not suitable for light-water SMRs based on the technoeconomic analysis. The transcritical ethanol cycle and regenerative reheat Rankine cycle have shown higher thermal efficiency and lower levelized cost of electricity than the baseline regenerative Rankine cycle.