Recent events in Iran demonstrate that dropping “bunker buster” bombs on nuclear plants is not an ideal, or even necessarily effective, way to prevent proliferation. It is far preferable to prevent the spread of nuclear-weapon-usable technologies in the first place.
A simplistic way to achieve that might be to halt the worldwide growth of nuclear power. Public approval of nuclear energy, however, is actually growing in the U.S., and the White House recently announced policies to quadruple American nuclear power by 2050 while also promoting nuclear exports. This surge of support is somewhat surprising, considering that new reactors not only pose radiation risks from nuclear waste and potential accidents but also produce electricity that costs considerably more than solar or wind power (which can be similarly reliable when complemented by batteries). But nuclear power plants are touted for other attributes, including their small footprint, constant output, infrequent refueling, low carbon emissions and ability to produce heat for manufacturing. If customers decide this justifies the higher cost—and are willing to wait about a decade for new reactors—then nuclear energy has a future.
That leaves only one other way to stop the spread of dangerous atomic technology – by prudently limiting nuclear energy to the “bomb-resistant” type, which entirely avoids weapons-usable material by disposing of it as waste, rather than the “bomb-prone” variety that creates proliferation risks by purifying and recycling nuclear explosives.
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Regrettably, however, the White House recently directed government officials to facilitate the bomb-prone version in a set of executive orders in May. That decision needs to be reversed before it inadvertently triggers an arms race, atomic terrorism or even nuclear war. As Iran has highlighted, ostensibly peaceful nuclear technology can be misused for a weapons program. That is why, from now on, the U.S. should support only bomb-resistant reactors and nuclear fuel.
Most Americans probably don’t realize that nuclear reactors originally were invented not for electricity or research but to produce a new substance, plutonium, for nuclear weapons such as the one dropped on Nagasaki. Every nuclear reactor produces plutonium (or its equivalent), which can be extracted from the irradiated fuel to make bombs.
This raises three crucial questions about the resulting plutonium: How much of it is produced? What is its quality? And will it be extracted from the irradiated fuel, making it potentially available for weapons?
Bomb-resistant nuclear energy—the only type now deployed in the U.S.—produces less plutonium, which is of lower quality and does not need to be extracted from the irradiated fuel. By contrast, bomb-prone nuclear energy produces more plutonium, which is of higher quality and must be extracted to maintain the fuel cycle.
Of course, a declared facility to extract plutonium in a country lacking nuclear weapons could be monitored, but history shows that international inspectors would stand little chance of detecting—let alone blocking—diversion for bombs. That is why the U.S. made bipartisan decisions in the 1970s to abandon bomb-prone nuclear energy, aiming to establish a responsible precedent for other countries.
In light of today’s growing concerns about nuclear weapons proliferation in East Asia, the Middle East and lately even Europe, one might assume that U.S. industry and government would promote only bomb-resistant nuclear energy—but that is not so. A growing number of venture capitalists and politicians are aggressively supporting technologies to commercialize plutonium fuel. They are doing so despite the security, safety and economic downsides that have doomed previous such efforts. These past failures are evidenced by the fact that of the more than 30 countries with nuclear energy today, including many which previously attempted or considered recycling plutonium, only one (France) still does so on a substantial scale—at considerable financial loss. However, if the U.S. government continues subsidizing nuclear technologies without regard to proliferation risk, then the plutonium entrepreneurs will keep hopping on that gravy train. Eventually, they even may find willing customers for their pricey, bomb-prone technology—but mainly among countries willing to pay a premium for a nuclear-weapon option.
The most egregious proposal has come from start-up Oklo, a company originally spearheaded by venture capitalist Sam Altman (who stepped down as chairman in April). It is pursuing “fast” reactors that can produce larger amounts of higher-quality plutonium, and it has declared the intention to extract plutonium for recycling into fresh fuel. Oklo even says it plans to export this proliferation-prone technology “on a global scale.” The Biden administration and Congress, despite the obvious dangers of dispersing nuclear weapons-usable plutonium around the world, chose to subsidize the company as part of a wholesale push for new nuclear energy. Then the Trump administration picked as secretary of energy an industrialist named Chris Wright, who actually was on Oklo’s board of directors until his confirmation. In 2024, Wright and his wife also made contributions to a fundraising committee for Trump’s presidential campaign totaling about $458,000, along with contributions to the Republication National Committee of about $289,000. In the first quarter of 2025, Oklo increased its lobbying expenditures by 500 percent compared to the same period last year.
Biden also gave nearly $2 billion to TerraPower, a nuclear energy venture founded by billionaire Bill Gates, for a similar but larger “fast” reactor that also is touted for export. Experts say this inevitably would entail far greater plutonium extraction, even though the company denies any intention to do so. The U.S. Department of Energy also has funded the American branch of Terrestrial Energy, which seeks to build exotic “molten salt” reactors that use liquid rather than solid nuclear fuel. Such fuel must be processed regularly, thereby complicating inspections and creating more opportunities to divert plutonium for bombs.
Most baffling are proposals for large “reprocessing” plants to extract huge amounts of plutonium from irradiated fuel without plausible justification. The company SHINE Technologies, with technical assistance from a firm named Orano, is planning a U.S. pilot plant to process 100 metric tons of spent fuel each year. This would result in the annual extraction of about a metric ton of plutonium—enough for 100 nuclear weapons. SHINE claims the plutonium is valuable to recycle as reactor fuel, but the U.K. recently decided to dispose as waste its entire 140-metric-ton stockpile of civilian plutonium because no one wanted it as fuel. The U.S. similarly has been working to dispose of at least 34 metric tons of undesired plutonium as waste.
Officials from five previous U.S. presidential administrations, and other experts including me, protested in an April 2024 letter to then president Biden that SHINE’s plan would increase “risks of proliferation and nuclear terrorism.” Despite this, President Trump recently issued an executive order in May that directed U.S. officials to approve “privately-funded nuclear fuel recycling, reprocessing, and reactor fuel fabrication technologies … [for] commercial power reactors.” Even more troubling, a separate order directed the government to provide weapons-grade plutonium—retired from our arsenal—directly to private industry as “fuel for advanced nuclear technologies,” which would jump-start bomb-prone nuclear energy before assessing the risks.
SHINE and a similar company, Curio, claim their facilities would slash the country’s radioactive waste stockpile. But realistically, they could barely dent its growth of 2,000 metric tons annually. They also propose to extract valuable radioactive isotopes for medical and space application, but these materials already are available elsewhere at less expense or are needed in such tiny amounts that they require processing only hundreds of kilograms of irradiated fuel annually, not the proposed hundreds of metric tons, which is a thousand times more.
All of these companies also claim their plutonium extraction would utilize new technologies that are “proliferation resistant”—but that, too, is bunk. As far back as 2009, six U.S. national laboratories concluded that, “there is minimal additional proliferation resistance to be found by introducing … [such] processing technologies when considering the potential for diversion, misuse, and breakout scenarios.”
Fortunately, some advanced nuclear energy technologies actually are bomb resistant. These include updated versions of America’s existing fleet of power plants and new reactor types that use tiny particles of coated fuel, which can bolster resistance to both accidents and plutonium extraction. The only question is whether our elected officials will have the wisdom to embrace this safer path. That would surely disappoint campaign contributors on the bomb-prone side of the nuclear industry. But it would allow us to modernize nuclear energy without inadvertently spreading nuclear weapons.
This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.