40 years later, Chernobyl's nuclear fallout is not what scientists expected
Forty years after the Chornobyl disaster, tiny radioactive particles still linger in the soil, carrying a dangerous legacy. Using powerful X-rays, scientists discovered that some of these particles have remained surprisingly stable, trapping radioactive substances inside instead of releasing them into the environment.
Key points
- Researchers analyzed six Chornobyl particles and found some retained much of their original crystal structure after 40 years.
- The particles fall into three classes, including fuel-like uranium dioxide and material fused with zirconium.
- The small sample size means the findings cannot yet describe contamination across the whole region.
Four decades after the Chornobyl nuclear disaster, microscopic radioactive particles remain in the surrounding soil and still require protective clothing to enter affected areas. Scientists have now completed the first structural analysis of such particles at the Rossendorf Beamline in Grenoble, examining six fragments recovered from the Chornobyl region.
The work was done by Dr. Christoph Hennig, a crystallographer at the Helmholtz-Zentrum Dresden-Rossendorf, with Tobias Weissenborn, a physicist and doctoral candidate at Leibniz University Hannover. The results showed that the nuclear fuel inside the six particles had retained much of its original crystal structure despite 40 years in the environment.
Three classes of particles
Weissenborn said the particles fall into three classes. One type remains chemically and physically similar to the nuclear fuel uranium dioxide, while another is partly or fully encased in, or fused with, its zirconium layer. The third type formed when the graphite moderator caught fire and burned for ten days, oxidizing the fuel into uranium oxides such as U 3 O 8.
However, every single particle has a different structure
— Tobias Weissenborn
How the particles were studied
The particles were isolated from Ukrainian soil samples and attached to tungsten electrodes, then enclosed in several containment layers for transport to Grenoble because of their high radioactivity. There, the team rotated each particle in an X-ray beam focused to 100 micrometers and measured it from 2,000 angles.
The researchers caution that the findings do not mean the contamination is becoming harmless. Weissenborn noted that every particle has a different structure and that only six particles from two locations were studied, so the results cannot support universal statements about health risks in the region.
