Some microscopic fuel fragments scattered by the Chernobyl disaster still retain much of their original crystal structure four decades later. The finding suggests that certain radioactive materials may remain trapped inside these particles longer than expected, delaying their release into soil or water rather than removing the hazard.
During the 1986 accident, debris from the exploding reactor carried radioactive “hot particles” into the environment. Just 8–50 micrometers across, these fragments contain radioactive material whose long-term behavior depends partly on how the particles change and break down.
Researchers from Germany’s Leibniz University Hannover and Helmholtz-Zentrum Dresden-Rossendorf examined six particles collected from two sites in Ukraine. According to Interesting Engineering’s report, the team used high-energy X-rays in Grenoble, France, to map the particles’ internal structure. They examined each particle from approximately 2,000 angles to build a detailed picture of its composition.
The nuclear fuel’s crystal structure remained largely intact, but the samples weren’t all alike. The analysis identified three groups:
- Particles resembling the original uranium dioxide fuel.
- Particles in which fuel had fused with the zirconium layer surrounding it in the reactor.
- Particles containing materials formed as the reactor’s graphite moderator burned.
That structural persistence could affect when radioactive material is released. Some substances produced through radioactive decay may stay inside the particles longer and enter the surrounding soil or water more slowly. The fuel fragments in these samples proved more resistant than expected.
[IMAGE:raketa.hu]Slower release doesn’t mean the contamination has become harmless. Particles that hold onto their radioactive contents can remain a long-term challenge because those materials may still be released later. An intact crystal structure is evidence of persistence, not proof of safety.
The researchers also caution against applying the finding to the entire Chernobyl-contaminated area. Six particles from two locations are too small a sample to establish how widespread this behavior is or what it means for regional health risks. Particle properties can vary considerably, so understanding their behavior requires more samples.
Further experiments are already being prepared to examine particularly radioactive materials from the reactor. For now, the findings provide no basis for lifting restrictions in the Chernobyl exclusion zone.
