SMRs

Small modular reactors (SMRs) are a class of nuclear fission reactors designed to be built in factories and transported to site for assembly. They are smaller than traditional large reactors, typically producing up to a few hundred megawatts of electric power (often defined as 300 MWe or less). The modular concept enables factory fabrication, standardization, and phased deployment, potentially reducing upfront capital costs and construction time. SMRs are conceived to support electricity generation, district heating, process heat, and other industrial applications, and to offer options for modular expansion.

Design features emphasize safety and resilience. Many SMR designs use passive safety systems that rely on natural circulation, gravity, and long-term heat removal without active power or operator action. The compact size and integrated layout can allow underground or offshore siting in some concepts. Standardized components aim to simplify licensing and maintenance. Proponents argue these features can reduce the risk of extreme events and shorten construction schedules compared with large reactors.

Deployment and economics are central to SMR development. Factory fabrication and mass production aim to improve quality and reduce costs, while modularity supports staged investment and potential use in remote or smaller grids. However, challenges include regulatory processes for new designs, financing, waste management, and public acceptance. The commercial viability of SMRs depends on performance, safety track records, and policy and market conditions.

Status: Several SMR designs have advanced to regulatory review or licensing in multiple countries, and some projects have been announced or are under construction. Global activity continues to expand with ongoing research, demonstrations, and partnerships involving industry, government, and academia.