Huge computer screens line a dark, windowless control room in Corvallis, Oregon, where engineers at the company Nuscale Power hope to define the next wave of nuclear energy. Glowing icons fill the screens, representing the power output of 12 miniature nuclear reactors. Together, these small modular reactors would generate about the same amount of power as one of the conventional nuclear plants that currently dot the United States – producing enough electricity to power 540,000 homes. On the glowing screens, a palm tree indicates which of the dozen units is on “island mode”, allowing a single reactor to run disconnected from the grid in case of an emergency.

This control room is just a mock-up, and the reactors depicted on the computer screens do not, in fact, exist. Yet Nuscale has invested more than $900m (£685m) in the development of small modular reactor (SMR) technology, which the company says represents the next generation of nuclear power plants. Nuscale is working on a full-scale prototype and says it is on track to break ground on its first nuclear power plant – a 720-megawatt project for a utility in Idaho – within two years. The US Nuclear Regulatory Commission has just completed the fourth phase of review of Nuscale’s design, the first SMR certification the commission has reviewed. The company expect final approval by the end of 2020. The US Department of Energy has already invested $317m (£241m) in the research and development of Nuscale’s SMR project.

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Nuscale is not alone in developing miniature reactors. In Russia, the government has launched a floating 70MW reactor in the Arctic Ocean. China announced plans in 2016 to build its own state-funded floating SMR design. Three Canadian provinces – Ontario, New Brunswick, and Saskatchewan – have signed a memorandum to look into the development and deployment of small modular reactors. And the Rolls-Royce Consortium in the UK is working on the development of a 440MW SMR.

Proponents say the time is ripe for this new wave of nuclear reactors for several reasons. First, they maintain that if the global community has any hope of slashing CO2 emissions by mid-century, new nuclear technologies must be in the mix. Second, traditional nuclear power is beset with problems. Many existing plants are ageing, and new nuclear power construction is plagued by substantial delays and huge cost overruns; large-scale nuclear power plants can cost more than $10bn (£7.6bn). Finally, advocates say that as supplies of renewable energy grow, small modular reactors can better handle the variable nature of wind and solar power as SMRs are easier to turn on and leave running.