Don’t call us ‘nuclear’, say nuclear fusion start-ups
Companies set to enjoy lighter US regulatory regime by avoiding words associated with conventional nuclear plants
For fusion start-ups, one of the industry’s biggest breakthroughs may have come not in physics but in branding.
Years of efforts to distance themselves from conventional nuclear power are beginning to pay off as US regulators prepare rules that would separate fusion and place it under a lighter licensing regime.
The industry’s best-funded companies and leading trade groups avoid the use of terms such as “nuclear” and even “reactor”, arguing that they wrongly evoke the risks associated with conventional nuclear power. “Smart marketing” as one veteran fusion investor put it.
The debate comes as billions of dollars pour into fusion, which seeks to replicate the process that powers the sun by fusing atomic nuclei rather than splitting atoms, as in conventional nuclear power plants.
More than 50 start-ups are racing to commercialise the technology, with Google and Microsoft among those backing companies in the hope of securing abundant clean energy for power-hungry AI.
A US government laboratory has demonstrated that a so-called net energy gain is possible through fusion, but no company has yet proved it can build a commercially viable power plant.
Commonwealth Fusion Systems was among the earliest companies to deliberately distance fusion from the language of nuclear power, according to executives and industry watchers. The US company is one of the sector’s biggest players, with about $4bn in funding and backing from Google.
Bob Mumgaard, chief executive, said the debate over whether to describe fusion as “nuclear” began about a decade ago. Fusion should “stand on its own” and be “judged on its merits”, rather than be defined by a term that “carries the good and bad” of the nuclear industry, he said.
Helion Energy, backed by OpenAI chief executive Sam Altman, similarly argues that “the common perceptions of ‘nuclear power’ do not apply to fusion” and refers to its machines as “generators” rather than reactors.
Some executives dismiss the term “reactor” altogether, saying it has little meaning outside engineering.
“Beer is technically made in a reactor,” one executive said. “Most people aren’t nuclear physicists.”
Fusion joins atomic nuclei rather than splitting them as conventional nuclear plants do, known as fission. Although both are technically nuclear reactions, fusion cannot sustain the runaway chain reaction that characterises fission.
The proposed rules by the Nuclear Regulatory Commission would regulate fusion facilities more like particle accelerators than nuclear plants, allowing many projects to fall under state rather than federal oversight.
That could give fusion companies an advantage as states compete to become the first “fusion state” by offering streamlined permits.
Christina England-Livengood, a partner at White & Case and a former NRC lawyer who helped develop the regulatory framework for Congress in 2023, said the industry’s advocacy “definitely” influenced the policy discussion as the commission considered a separate regulatory pathway for fusion.
That decision laid the foundation for the rules now being finalised, she said, adding that industry input helped regulators “see the rest of the picture” at an agency that had traditionally been “very closed”.
The Fusion Industry Association, which was one of the leading voices advocating for a separation of fusion from conventional nuclear power regulations, also makes “conscious decisions” to avoid the use of the term “nuclear” and “reactor”, said Andrew Holland, its chief executive.
The distinction is crucial for fusion companies, which have attracted more than $11.5bn in private funding to date, according to PitchBook, and are racing to connect commercial power plants to the grid. It could spare them the lengthy licensing process designed for nuclear fission reactors.
The industry’s argument rests on technical differences. Fusion systems still use radioactive fuels such as tritium, and structural materials become radioactive after prolonged neutron exposure. Even so, the International Atomic Energy Agency describes fusion as “inherently safe” because the reaction cannot sustain a runaway chain reaction.
Fuels such as tritium have a half-life of 12.3 years and are generally far easier to manage than many radioactive materials produced by fission reactors, some of which remain hazardous for millions of years.
Colin McNally, a fusion physicist, argued that, despite tritium’s relatively short half-life, the need for an on-site inventory would inevitably become a political issue as companies sought to build larger power plants.
“There’s a difference between poisoning the landscape for 20,000 years and causing people damage for 10 years,” he said, adding that harming people for a decade was still bad.
CFS chief executive Mumgaard was steadfast. “Fusion deserves to be its own thing,” he said. “So we should make language that highlights that.”