TO 40 years from the disaster of Chernobylthe most serious nuclear accident in history never ceases to be talked about. Since the creation of New Safe Confinement to the animal species that have transformed the exclusion zone into an enormous nature reserve, this unique territory in the world is still able to pose challenges and questions four decades later. But how safe is the area today? And is it true that animals have returned to live in these lands? To better understand the situation we must start from the days immediately following the disaster and the creation of the first protective sarcophagus.
The Chernobyl sarcophagi
The first sarcophagus was hastily built in 1986directly above the reactor number 4 which contained – and still contains – 220 tons of highly radioactive material. This structure was created by employing liquidators 400,000 cubic meters of concrete and beyond 7000 tons of steel.
The sarcophagus was effective, but temporary: it was sealed bad and then the water infiltrated and began to corrode the reactor. Thus in 2019 the second sarcophagus, the New Safe Confinement: a tall arched structure 109 meterslong 162 meters and wide 257funded by 45 countries, which was built from a safe distance and then slid on tracks over the old sarcophagus. The steel frame is equipped with a membrane that guarantees hermetic closure with the original structure to avoid the dispersion of dust. A ventilation and air conditioning system is also installed inside for the constant control of humidity and temperature. The structure is designed to withstand earthquakes up to magnitude 6.0 and sudden changes in climate.
The disaster, however, did not only involve the area immediately around Chernobyl but the radioactive material covered a very large area. Precisely for this reason the Soviet government first, and then the Ukrainian one, established regulations exclusion zones: that is, areas within which human presence was prohibited.
The exclusion zone
The exclusion zone has changed over time. Initially it had a radius of 30 km around the power plant, but it soon became clear that it was not enough. Today, considering both the Ukrainian and Belarusian parts, the total area exceeds 4,300 km² and is divided into four areas with increasing levels of restriction as you get closer to the power plant. The most dangerous hotspots clearly lie directly beneath the melted reactor – an area that liquidators have nicknamed “elephant foot”, from the name of the form taken by corium solidified. In that specific area the radiation levels remain lethal even today, reaching even 100 mSv/year. And this is precisely why the sarcophagus was made.
In the external areas, the most distant ones, the situation is very different: we are talking about values around 6 mSv/year, therefore approximately 16 times lower. But in this whole story there is a truly extraordinary aspect that we have not yet mentioned: by removing the human being from the equation, the authorities have unintentionally created one of the largest nature reserves in Europe.
The animals of Chernobyl
In recent decades not only has vegetation increased but also animals have returned to live here. This was possible, in part because of the decay natural of radionuclides and partly for the dilution environmentalor that process by which part of the deposited radioactivity has been washed away by atmospheric agents…. although this does not mean that the area is now free of radioactivity. Otherwise we humans too would have returned to live there. And in fact the animals that live there are directly affected by radiation: for example red and black bugs here they have irregular color patterns, or the swallows they have more tumors and abnormal coloring than control populations.
However, it remains to be understood whether these conditions are prohibitive for the development of a population or not. On the one hand there are researchers like Anders Moller And Timothy Mousseau whose position is that radiation is severely affecting Chernobyl’s animal populations, making them suffer and causing their numbers to steadily decline. On the other hand there are studies, such as those of TG Deryabina which present an opposite picture, with populations that are successfully reproducing. In some studies, such as that of Galvan et al. of 2014it even seems that some species may show early signs of evolutionary adaptation to radiation – although it is still too early to say for sure.
Which of the two sides is right? It’s hard to say at the moment, the scientific community is split. And this is because the situation that has been created in Chernobyl over the last 40 years is unique and extremely complicated, and therefore many more studies will be needed before reaching a conclusion that everyone can agree on. Well. At this point I would say that we have resolved all the main issues relating to the Chernobyl disaster, from that April 26th to today. And what remains to be seen is precisely this: what is the situation today regarding radioactivity? And will human beings ever return to inhabit the exclusion zone in the future?
The problem of radioactivity today
As for repopulation, this is actually already underway. In Belarus for example, since 2010 some areas, such as the regions of Gomel and Mogilev, have been progressively repopulated, given that analyzes have recorded levels of radioactivity compatible with stable settlement. But these are more peripheral regions: the areas closest to Chernobyl are still off-limits. Among other things, to make the situation even worse, there is the ongoing conflict with Russia. The passage of heavy vehicles, for example, has re-mobilized in recent years Cesium-137 which had been deposited in the soil over the decades. But not only that: on February 14, 2025, at 1:50 am, the sarcophagus was hit by a drone equipped with an explosive charge – although fortunately this did not lead to an increase in the values of radioactive isotopes in the area. In the face of all this: will human beings ever return to permanently populate these lands?
The answer is complex and clashes with the harsh realities of nuclear physics, given that some isotopes have very long half-lives.
In fact, it is true that reclamation systems exist, but applying them on such a large scale is very complex, and above all very expensive. For this reason, the most realistic scenario for the near future is not that of an urban rebirth, but of a radioactive sanctuary: an area dominated by wild nature, which can only be visited with special permits and for extremely limited times.
