The US National Academies said in a recent report that the world confronts “an existential challenge” in responding to climate change, resulting in an urgent need to reduce greenhouse gas emissions from all sectors of the economy. It asked: “What will it take for new and advanced nuclear reactors to play a role in decarbonisation?”

Advanced reactors encompass a wide range of technologies, including next generation water-cooled reactors, non-water-cooled reactors such as lead or sodium fast reactors, and fusion reactors, which aim to replicate the processes that power the Sun.

Some advanced reactor concepts are relatively new, while others have been under consideration for decades and used in research, test, and prototype reactors around the world.

Reactors using any of these technologies that have electric generating capacity of 300 MW or below are classified as small modular reactors (SMRs) by the International Atomic Energy Agency (IAEA). They can be factory-built and transported for onsite assembly, allowing for greater flexibility and faster production.