Nuclear Waste Disposal: Nanometer-Sized “Soccer Balls” Made of Plutonium

At Karlsruhe Institute of Technology (KIT), scientists have been conducting research for more than four decades on the chemistry of actinides, which include plutonium. These elements play an important role in the safe disposal of radioactive waste. In a joint study with the Joint Research Center Karlsruhe, KIT researchers have now made significant progress in investigating plutonium(VI), a chemical state of plutonium.

“We investigated how dissolved plutonium compounds behave at different pH levels,” explains Dr. David Fellhauer from KIT’s Institute for Nuclear Waste Management. In aqueous solutions, complexes containing three plutonium atoms dominate. Under strongly alkaline conditions, these formed small crystals within a few days, and the researchers have now been able to elucidate their structure.

Pu₆₀ – A Nano-Soccer Ball of Superlatives 

“In the process, we found two types of crystals consisting of spherical cage units in which 60 plutonium atoms are linked via oxygen,” notes Fellhauer. “These Pu₆₀ clusters are the largest known cage compounds of plutonium.”

Their geometry is particularly remarkable: The arrangement of the atoms corresponds to a truncated dodecahedron, a rare geometric shape in structural chemistry. This distinguishes them significantly from the well-known carbon molecule C60, which also adopts a spherical shape and resembles a soccer ball.

The new findings provide important insights into the chemistry of the actinides. At the same time, they solve a decades-old mystery: Researchers had already observed similar crystals during the Manhattan Project. However, their structure could not be determined with the analytical methods available at the time. Only now has the KIT team been able to provide a clear explanation for this finding.

jho, July 13, 2026