TerraPower and PanTera expand Belgium actinium-225 production capacity

A new actinium-225 production line in Belgium now has the three things isotope manufacturers obsess over most: a host site, an operator and a feedstock plan. TerraPower Isotopes and PanTera said the expanded collaboration would place the line at the Institut des Radioelements, or IRE, in Belgium, while TerraPower Isotopes supplies additional starting material to keep the effort fed.

That matters because Ac-225 is one of the most watched isotopes in targeted alpha therapy. Its half-life is about 9.92 days, short enough to make logistics unforgiving but long enough to be useful in radiopharmaceuticals. Each decay chain releases four alpha particles, a dense burst of damage that can be aimed at cancer cells while limiting exposure to surrounding tissue. The U.S. Department of Energy has repeatedly described Ac-225 as in short supply, and the pressure on supply has only grown as clinical programs look for more material.

The Belgian expansion does not erase that bottleneck overnight, but it does make the pipeline look more real. This is not a loose memorandum sitting on a shelf. IRE will host and operate PanTera’s new Ac-225 production line, and TerraPower Isotopes will provide the starting material that keeps the system moving. For a field where access has often been the limiting reagent, that combination is the point.

The move also builds on a timeline that has been taking shape for years. TerraPower Isotopes and PanTera first announced a strategic collaboration on June 26, 2023 to increase global availability of actinium-225. PanTera, the Belgian joint venture created by SCK CEN and IBA, had already been developing a thorium-actinium generator approach for a production facility on the premises of SCK CEN. In 2025, PanTera began construction of its Actinium Production Centre in Mol, with the site expected to become operational in 2028 and first commercial Ac-225 supplies scheduled for 2029.

That is why the new Belgium arrangement reads less like a press release flourish and more like another piece locked into place. Ac-225 supply still has a long road ahead, and the clinical demand curve is not waiting. But with IRE, PanTera and TerraPower Isotopes now tied together in a defined production chain, the isotope is looking less like a scarce experiment and more like the start of a manufacturing program.