Small Modular Reactors (SMRs) are defined as reactors with an electrical output of up to 300 MWe. They offer several potential advantages:
- Factory fabrication — components can be manufactured in a factory and transported to site, reducing construction time and cost.
- Lower capital cost — smaller individual investment compared to large reactors (though cost per MWe may be higher).
- Flexible siting — can be deployed in locations not suitable for large reactors.
- Scalability — multiple modules can be added incrementally as demand grows.
Several SMR designs are under development worldwide. In the UK, Great British Nuclear (GBN) conducted a competitive SMR technology selection process and in February 2025 selected Rolls-Royce SMR (a 470 MWe PWR design) as the preferred technology, with plans for three initial units. In the USA, the NuScale VOYGR design received NRC design certification, though its first planned project (at Idaho National Laboratory) was cancelled in 2023 due to rising costs.