A major European nuclear research reactor has taken a significant step toward eliminating weapons-grade uranium from its fuel supply. Belgium’s SCK CEN has formally requested regulatory approval to convert its BR2 reactor to low-enriched uranium, a move that could reshape nonproliferation efforts across the continent.
The BR2 facility currently runs on highly enriched uranium, the same material used in nuclear weapons. Converting to low-enriched fuel slashes diversion risks while maintaining full operational capacity. Argonne National Laboratory reports that approval for the conversion proposal could arrive in 2027, with system modifications starting shortly after.
Unlike commercial power plants with fixed core designs, the BR2 presents an unusual engineering puzzle. Its core configuration changes every few weeks. The reactor operates in seven distinct 30-day cycles annually, with engineers rearranging components between cycles to accommodate varying experiments and production demands.
That variability ruled out any standardized conversion blueprint. Instead, researchers had to demonstrate that low-enriched uranium could perform safely across every conceivable core arrangement. Over ten years, Argonne specialists collaborated with Belgian counterparts using advanced computer modeling to simulate extreme operating conditions. Their analyses confirmed the new fuel meets international safety standards for all configurations.
“We needed a design that reflects how the reactor is actually used,” said Jeremy Licht, manager of Argonne’s Research Reactor Methods group. “Then we have to show it can meet safety requirements across a wide range of uses.”
The stakes extend far beyond nuclear security. BR2 supplies roughly 25 percent of global molybdenum-99, which decays into technetium-99m, a critical imaging agent for detecting cancer and heart disease. The facility also produces therapeutic isotopes like Lutetium-177 and Terbium-161. Additionally, the reactor supports silicon doping, a process that creates semiconductors for electric vehicles, wind turbines, and high-power electronics.
Argonne has converted reactors worldwide for decades, yet BR2 ranks among its most challenging projects. Success here offers a template for Europe’s three other high-performance research reactors facing similar complexity. Proving BR2 can operate on lower-grade fuel demonstrates that modern science no longer needs weapons-grade uranium.
