Uranium fuel as weapons material
Posted: 23rd July 2024
Next-generation nuclear reactors are heating up a debate over whether their fuel could be used to make bombs, jeopardising efforts to prevent the proliferation of nuclear weapons. Uranium in the fuel could theoretically be used to develop a nuclear weapon. Older reactors use such low concentrations that they don’t really pose a weapons proliferation threat. But advanced reactors would use higher concentrations, making them a potential target of terrorist groups or other countries wanting to take the fuel to develop their own nuclear weapons, some experts warn. They argue that the US hasn’t prepared enough to hedge against that worst-case scenario and are calling on Congress and the Department of Energy to assess potential security risks with advanced reactor fuel. The US Nuclear Regulatory Commission (NRC) certified an advanced small modular reactor design for the first time last year. And we’re likely still years away from seeing commercial plants in action. But if the US ever wants to get there, it’ll also have to build up a supply chain for the fuel those advanced reactors would consume. The Inflation Reduction Act includes $700 million to develop that domestic fuel supply. Today’s reactors generally run on fuel made with a uranium isotope called U-235. Naturally occurring uranium has quite low concentrations of U-235; it has to be “enriched” — usually up to a 5 percent concentration of U-235 for a traditional reactor. Smaller advanced reactors would run on more energy-dense fuel that’s enriched with between 5 to 20 percent U-235, called HALEU (short for high-assay low-enriched uranium). That higher concentration is what has some experts worried. “If the weapons usability of HALEU is borne out, then even a single reactor would pose serious security concerns,” says a policy analysis penned by a group of nuclear proliferation experts and engineers published in the journal Science last month (including an author credited with being one of the architects of the first hydrogen bomb).