The Trump administration has announced that it has selected several nuclear start-ups to participate in a project that would allow them to use plutonium stockpiles inherited from the Cold War. This plan has alarmed nuclear non-proliferation specialists.
Cold War-era nuclear technology is making a major comeback in the US. The Trump administration has selected several nuclear start-ups that could be granted the right to tap into stocks of military-grade plutonium that were produced until the early 1990s for use in nuclear weapons. This plutonium will then be repurposed as fuel to power small modular reactors.
Five companies, including the Franco-Italian small nuclear reactor specialist Newcleo, will enter into “advanced negotiations” with US authorities to use a portion of the 99 tons of plutonium that the US stores at several highly secure sites.
The selected start-ups will have to prove that they can safely handle and transport the highly unstable radioactive material, which could be used to develop dozens of new nuclear weapons.
Bulky plutonium stockpiles
In May 2025, President Donald Trump put the plutonium issue back on the table – much to the dismay of nuclear non-proliferation experts.
The US has struggled to find a solution for disposing of these stockpiles for decades. “Storing them costs money. We have to ensure they are kept secure and that the plutonium containers do not corrode. These are expenses for stockpiles that the United States doesn’t want anyway, since it no longer needs them for its nuclear arsenal,” explained Noah Mayhew, a non-proliferation and nuclear governance specialist at the Vienna Center for Disarmament and Non-Proliferation (VCDNP).
At the end of the Cold War, the US and Russia tried to find a way to make use of this plutonium by turning it into a source of energy. It did not work, and the plan was abandoned during Barack Obama’s second term. When Joe Biden came to the White House, he wanted to safely bury the stockpiles in New Mexico. The project, however, stalled because it was too expensive and complicated to implement during his term.
Trump’s return to the White House marked a 180-degree turn on the issue: Why not involve the private sector to find a solution for the plutonium that the government has been desperately trying to get rid of?
The start-up route seemed particularly promising to the new administration since Trump has an ambitious plan for nuclear renewal in the US.
American plutonium rather than Russian uranium?
Among the factors driving the move is AI’s voracious appetite for energy, according to some experts. “One of the main reasons for Donald Trump’s support of nuclear power is the US need to generate ever more electricity to meet the immense demands of the AI industry and its data centres,” explained Mayhew.
The nuclear start-ups selected by the White House all claim they have an urgent need for access to new fuel sources, particularly since the 2022 start of Russia’s full-scale invasion of Ukraine. “There is a geopolitical element to this story: indeed, the main supplier of enriched uranium, used as an energy source for these reactors, was Russia,” noted Chris Spedding from the University of Leicester’s Leverhulme Centre for Humanity in Space.
“The United States now wants to produce more electricity [through nuclear power] without having to buy enriched uranium from Russia. But at what cost?” asked Moritz Kütt, a physicist at the University of Hamburg and founder of the Hamburg Nuclear Disarmament Laboratory.
For Donald Trump, it’s time to “Make Plutonium Great Again". Except that “plutonium is one of the most toxic substances ever created, far more so than uranium. Inhaling even a tiny amount is enough to put you at risk of developing lung cancer,” noted Mycle Schneider, coordinator, editor and publisher of the World Nuclear Industry Status Report (WNISR).
Experts are sceptical of the idea of letting start-ups handle such substances. “It’s extremely difficult to handle, and very strict protocols will be needed to oversee this project,” said Spedding.
Another major proliferation risk, Kütt warns, is that obtaining separated plutonium for weapons is a much easier process than having to enrich uranium. It also doesn’t take much to create a bomb. “While the exact amount of plutonium needed to make a nuclear explosive is classified information, we can say that a mass the size of a melon is sufficient,” explained Schneider.
Proliferation risk
The plutonium stocks right now remain stationary and are stored in highly secure facilities, “but if we allow private companies access to it, we will automatically increase the number of transport routes and the number of people handling it, which will heighten the risk of it being lost or stolen,” warned Spedding.
International organisations such as the International Atomic Energy Agency (IAEA) might be able to help make the process more secure. But beyond security concerns, “the signal sent by the United States is really not a good one,” warned Mayhew. When it comes to nuclear disarmament, “selling plutonium that can be used to make weapons to private companies does not send the best message", he noted.
Spedding concurs. “Other countries might think that if the United States is using plutonium, why shouldn’t they do the same?” he explained.
The argument from start-ups seeking quick access to plutonium as an alternative to enriched uranium from Russia also fails to convince several non-proliferation experts. “It’s not like at gas stations, where you can freely choose the type of fuel for reactors,” noted Kütt. Converting plutonium into an energy source is also very costly and time-consuming. “Producing the very first kilowatt-hour from plutonium would take years, if not decades,” he asserted.
The Trump-style plan to “unlock plutonium” for nuclear start-ups appears poorly conceived and hastily put together, many experts warn.
Then there’s also the issue of a potential conflict of interest. In September 2025, Democratic Senator Edward Markey sent a letter to the US president saying he was concerned that US Energy Secretary Chris Wright is working in the interest of nuclear power company Oklo, of which he used to be a board member before resigning to join the Trump administration.
“I am concerned that your Administration is moving forward with plans to transfer plutonium to Oklo and allow it to build a reprocessing plant not because these proposals make sense for the United States, but because Oklo stands to benefit financially and Secretary Wright is acting in his former company’s interest,” wrote Markey.
This raises the question of whether the entire plan is primarily a major PR stunt for these start-ups, which will then be able to raise funds more easily from investors impressed by the White House’s official backing.
This article has been translated from the original in French.
