Can Small Nuclear Reactors Help Solve Climate Change?

Much of the world has been turning away from nuclear power, with its aging plants, legacy of meltdowns and radioactive waste. But some governments, big companies and billionaires including Bill Gates and Warren Buffett are convinced the technology can help save the planet. Unlike wind and solar sources, nuclear power can be switched on and off at any time, and without the planet-warming emissions produced by gas and coal. Billions of dollars in investments are going toward a new generation of so-called small modular reactors (SMRs), which ultimately could provide a safe and nimble source of carbon-free energy — if they can overcome challenges related to economics, safety and public opinion.

Of the more than 70 such reactors that the International Atomic Energy Agency lists as in some stage of design or development, the smallest are less than 5 meters (16 feet) in diameter and 10 meters in height. (The plant that would be built to operate the reactor would be bigger, of course.) SMRs typically have less than 300 megawatts of generating capacity, about a third of that of existing reactors. The “M” in SMR — modular — means these reactors can largely be built in factories and shipped in standardized parts for assembly on-site. That means shorter construction times and greater flexibility to expand to meet demand.