As a blue coach stops outside the Chernobyl nuclear-power plant, friendly stray dogs approach it. It passed through several Ukrainian military checkpoints – necessary because Russian troops briefly occupied the plant on the first day of the invasion in 2022. The next shift of workers set for a 14-day stint at the site has been rushed out. Just above the main entrance, employees eat a subsidized lunch of Ukrainian origin food. The cafeteria is buzzing, even though the last of the plant’s four reactors shut down forever in 2000.
The disaster that began here on 26 April 1986 was devastating, and not just for those who lost their lives during and immediately after.
Workers dressed in three layers of white cotton go in and out of the “Golden Corridor,” a narrow hallway nearly a kilometer long that runs the length of the plant, its walls made of distinctively Soviet gold-painted aluminum and its floor a staggering expanse of cracked, cracked tiles. Along its length there are pans with wet rugs, to collect any possible radioactive dust on the bottom of the shoes, and old whole-body radiation-scanner doors: only the clean ones will pass through. Some of those passing through the corridor are involved in radiation monitoring. Many more do the extremely slow business of decommissioning and dismantling. And some are still making new scientific discoveries.
The unfolding of the accident started from here 26 April 1986 It was devastating, and not just for those who lost their lives during and immediately after it. But something good has come from this. It has provided a unique laboratory: an unnatural experiment that has been yielding valuable lessons on the biology, ecology and sociology of nuclear accidents for four decades.
When reactor number four exploded during a safety test, its core was exposed to air. More than 100 radioactive elements flowed out. Inert gases such as xenon and krypton dissipated rapidly and harmlessly. But the radioactive atoms that settled the region and its people – from iodine (which loses half its volume to decay every eight days) to technetium (which takes 200,000 years to decay) – continued to linger in the environment. It is the continued tracking of these radionuclides, particularly strontium and cesium, which are of most concern to human health, that has worried many researchers ever since.
After the accident Gennady Laptev and Oleg Voytsekhovich were assigned to assist as newly minted graduates. Soviet scientists from all walks of life joined him to take environmental stock of what had been fabricated. Dr. Laptev soon found himself on helicopter missions, hanging detectors over the destroyed reactor to determine the amount of radiation coming out.
Today they both are, and still are, senior researchers at the Department of Environmental Radiation Monitoring of the Ukrainian Hydrometeorology Institute. In a cold office in Kiev – heating and electricity go on and off in wartime Ukraine – they finish each other’s sentences as they describe what they have learned about radionuclides’ travel through lakes, rivers and groundwater.
Some of his most important work was determining radiation exposure from drinking water. After the accident, the local people are afraid of what is coming out of the tap. But Messrs. Laptev and Voitsekhovich showed that it provided no more than 10% of their total long-term internal radiation dose, and probably closer to 1%. The rest came from food and especially milk.
truth and consequences
The example that Chernobyl provides of how landscape, water dynamics, and human behavior affect radiation exposure will be important for responding to future disasters. Scientists never stop studying it, because radioactive isotopes can move in surprisingly new ways.
Most of the time, even when radiation levels are found to be increasing, they are still within acceptable limits. But sometimes those limits are violated. Dr. Laptev and Voitsekhovich talk animatedly about the natural drainage of Chernobyl’s cold ponds, which until 2014 were filled with water from the Pripyat River. The relatively clean groundwater beneath the ponds acted as a barrier, pooling into highly contaminated groundwater close to the ruined reactor. As the cold ponds slowly dry up, strontium levels in local waterways have begun to rise above WHO drinking water guidelines.
Valery Kashparov of the Ukrainian Institute of Agricultural Radiology may be the world’s leading expert on how the shower of radioactive particles affects the land and the food that comes from it. The intensity of rainfall at any one place is not a fixed factor. Soil probably matters most: peaty and sandy earth releases its pollutants far more easily to growing plants than black, humus-rich soil. And they found that different foods absorb radionuclides in different ways. Oats disproportionately draw strontium; Peas, Cesium. However, wheat and potatoes release more radionuclides into the earth.
Dr. Kashparov has compiled a long list of agricultural measures to reduce risk. Feed animals and fish a chemical called Prussian blue that binds with cesium and helps excrete it; Convert iffy milk into a form (such as butter or cheese) that can eliminate dangerous radioactivity; Add lime or mineral fertilizer to the soil to inhibit absorption.
Yet human behavior complicates the matter. Initially, when radioactive iodine was still abundant, milk contributed greatly to the spread of radiation because it was a means of barter for smallholders. For any post-disaster agricultural playbook to be effective, it must take into account local economies, dietary habits and risk tolerance, and focus on encouraging public awareness, Dr. Kashparov emphasizes.
Another factor in how radionuclides travel from soil to food is the diversity of bacteria nearby. Few people have given more thought to the safety problems of nuclear power plants than Olena Pareniuk of the Institute for Nuclear Power Plants. His work has shown that various bacteria can hinder or enhance translocation. Follow two preventive measures: Inoculate the soil with a barrier type and your crop will be cleared. Introduce an improved variety and the plant becomes a disposable pollutant sponge that helps clean the soil. The results of laboratory tests of both technologies are modest but encouraging.
Dr. Pareniuk has also studied the bacteria living inside Chernobyl’s ruined reactor. They survive and thrive even in inhospitable alkaline environments, which contain virtually no nutrients. Even more amazing, they’re breaking down a wildly radioactive mixture of molten uranium fuel, concrete and a metal called corium. “Whatever material humans create, nature finds its own insects to decompose it,” says Dr. Pareniuk.
Even more promising stories have emerged further up the food chain. Jim Smith of the University of Portsmouth began studying Chernobyl in 1990 as a physicist. But he has since become an expert on the area’s wildlife. Clearing out exclusion zones is now a well-documented experiment in redistribution. It is not that when people left the animals took over. Large animals especially flourished; Wolf and deer populations recovered and long-extinct species such as the lynx returned. There is still some debate about the long-term effects on small creatures such as barn swallows and butterflies, among other things, but in general the accident left little legacy in the animal populations or their DNA. There are no three-eyed fish in this area (although sexual development of perch seems to be slower in the most polluted areas).
something in the air
A more damaging consequence of the accident, says Dr. Smith, is the misunderstanding of radiation risks among the public and policymakers. Apart from the initial increase in (mostly non-fatal) thyroid cancer, it is almost impossible to accurately calculate human deaths resulting from radiation exposure. Other factors, not least natural radiation from Earth, increase lifetime cancer risks that were not markedly increased by the disaster. Yet this is not the assumption. Chernobyl gave the world a multi-generational case of heebie-jeebies, widespread fantasies of mutant creatures and an immature fear that has ultimately influenced energy policy.
As the Golden Corridor reaches the remains of reactor number four, now under an aircraft-hangar shaped arch, known as the New Safe Confinement (NSC), wet carpet and security doors go up. It was installed in 2016 to complement the concrete “sarcophagus” hastily built over the reactor in 1986. It cost $1.6 billion and was intended to prevent increasing radiation leakage for 100 years.
On Valentine’s Day in 2025, that timeline was cut short. A Russian drone hit the NSC, causing a fire that burned off more than half of the internal protective layer. At the back of the NSC is a modern control room that is in stark contrast to the Soviet design of the plant’s other nerve centers. As engineers grapple with how the damage will affect the NSC’s ability to preserve the remains of the core, eyebrows are raised. Unfortunately more research is needed on this forty years on.
