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. 40 years later, Chernobyl’s nuclear fallout is not what scientists expected.

The explosions that devastated the reactor released enormous quantities of debris, leaving behind contamination that continues to pose serious health risks. Even after 40 years, particles measuring just 8 to 50 micrometers remain highly radioactive, and entering affected areas still requires protective clothing. Scientists have now taken a closer look at these tiny remnants and uncovered a surprising finding: some have preserved much of their original internal structure despite decades of exposure to the environment.

"There are three classes of these particles," explains Tobias Weissenborn, a physicist and doctoral candidate at Leibniz University Hannover. "First, there are particles that are chemically and physically still very similar to the nuclear fuel uranium dioxide. Then, there are particles that are partially or fully encased in, or completely fused with, their zirconium layer." The second category originated during the extreme temperatures reached inside the reactor.