Nearly 40 years after one of the world's worst nuclear disasters does not mean that the danger has completely disappeared. Scientists have revealed that the radioactive fuel particles spread into the environment after the explosion in Chernobyl are much more durable than expected.
The explosion that occurred in reactor number 4 of the Chernobyl Nuclear Power Plant in Ukraine in 1986 caused a large amount of radioactive material to spread into the environment. Despite the decades that passed after the disaster, it was determined that some radioactive fuel particles found in the region retained their properties.
In the study conducted by researchers at Leibniz University Hannover and Helmholtz-Zentrum Dresden-Rossendorf, radioactive residues that spread into the environment after the explosion and are referred to as "hot particles" in the scientific literature were examined. It was determined that these particles, which were only 8 to 50 micrometers wide, retained their radioactive properties despite the passage of nearly four decades.
Researchers analyzed six radioactive particles as part of the investigation. The results revealed that these particles exhibited a more stable structure than expected under environmental conditions.
The study's authors noted that Chernobyl fuel particles act as persistent sources that can retain radioactive substances such as fission products and actinides in the environment for long periods of time. Researchers emphasized that the preservation of the internal structures of the particles even after about 40 years indicates that radioactive substances can persist in the environment for many years.
Tobias Weissenborn, the author of the study, explained that the particles examined were divided into three different groups. The chemical and physical properties of the particles in the first group remained broadly similar to uranium dioxide found in nuclear fuel. The particles in the second group were partially or completely covered with or fused with the zirconium layer.
It was stated that the formation of particles in the third group was caused by the ignition of the graphite moderator in the reactor and burning for about 10 days.
The research team used X-ray diffraction experiments for the first time to study the internal structure of radioactive particles. Thanks to this method, it was seen that the original nuclear fuel structure in some particles changed very little despite being exposed to environmental conditions for decades.
The findings showed that the environmental effects of the Chernobyl disaster were not limited to those experienced in the past, but that the long-term behavior of radioactive fuel residues was also important.
The researchers underlined that the results obtained were not sufficient to make a definitive and general judgment about the health risks in the region. For this, samples taken from many more points around Chernobyl need to be examined and the stability of the particles under different conditions must be investigated.
While the study reveals that radioactive particles in Chernobyl can maintain their existence and structural properties even after decades, it shows that more comprehensive research is needed to understand the long-term effects of these residues on the environment.
