Emerging Small Modular Reactors: Comparative Insights into Technologies, Passive Safety, and Future Energy Applications

Small Modular Reactors (SMRs) are increasingly regarded as a key option for decarbonizing energy systems while enhancing grid flexibility. This paper presents a comparative review of major SMR concepts, addressing technological, economic, safety, environmental, and industrial application aspects. The analysis covers light-water reactors, sodium-cooled fast reactors, molten salt reactors, and high-temperature gas-cooled reactors, with particular emphasis on passive safety systems and factory-based modular construction. Beyond electricity generation, the study highlights the potential of SMRs for cogeneration, seawater desalination, hydrogen production, and high-temperature process heat. Regulatory, financial, and socio-acceptability challenges are also examined, as they represent critical factors influencing future deployment. The review identifies both opportunities and barriers, concluding that SMRs could play a significant role in the global low-carbon energy mix between 2030 and 2050, provided that technological standardization, cost reduction, and licensing frameworks evolve in a coordinated manner.