The period of “Chornobyl’s decay”

Twenty-three years have passed since The Day of April 26 divided human fates into “before” and “after” the disaster at the Chornobyl Nuclear Power Plant. Until this day it is the world’s worst anthropogenic catastrophe unmatched for its environmental impact.

For Ukraine Chornobyl is an everyday reality and a host of global-scale problems. Unfortunately, the problems caused by the catastrophe are as acute today as they were 23 years ago. Can one get used to devastated villages and abandoned fertile land?

Today nothing prevents us from learning in detail what was happening on the banks of the Prypiat in late April—November 1986. In May 1986 foreigners were the first to learn the truth: on April 30 a Geiger counter on a Swedish nuclear power plant detected an unacceptably high level of radiation. After the Swedish government ascertained that the discharge did not take place in Sweden, it made an official inquiry. Mikhail Gorbachev addressed the people only 18 days after the disaster, on May 14. And three years passed before the information on the radioactivity conditions was declassified and publicized.

After the explosion at the Chornobyl Nuclear Power Plant, the scientists at the Institute for Nuclear Research (National Academy of Sciences of Ukraine) identified two groups of radionuclides emitted from the damaged reactor. One of them included volatile radioactive substances carried up high in aerosols with the streams of warm air (iodine-131, iodine-135, cesium-134, cesium-137, and strontium-90). Nearly 30 percent of cesium accumulated in the reactor core was emitted.

The other group included radionuclides with relatively high boiling temperature, which were emitted as part of the nuclear reactor core. Their emission rate was lower (nearly three percent of the total amount of fuel). These 5–6 tons of crushed uranium, the products of its fission, and transuranic elements (plutonium, curium, and americium) dealt the heaviest blow to the environment in terms of radioactivity.

According to the UN Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), 20 radionuclides had a major effect on the irradiation of people (particularly, isotopes of barium, magnesium, iron, curium, tellurium, etc.). Seven of them, carbon-14, cesium-137, zirconium-94, ruthenium-106, strontium-90, cerium-144, and iodine-131, are encountered more frequently than the others.

Radioisotopes of iodine, which were present in the air in the largest quantities, were the most dangerous for people. Therefore, Ukrainians who were outside under the radioactive clouds in the last days of April and early May picked up plenty of this isotope. Their thyroid glands accumulating this substance, received the largest dose of irradiation of all the parts of body, and suffered worst. As a result, several years after the Chornobyl disaster, doctors registered a spike in thyroid cancer among children.

Some experts assert that the life of radioactive iodine is short, so it cannot be affecting our health today. In fact, radioactive iodine does not disappear within eight days, as some write, but plants itself in the thyroid of its victims and stays there for 80 days.

Back in 1978 the children’s doctor Helen Caldicott warned humanity that the silence of doctors about the consequences of nuclear technologies and radiation would lead to an increase in cancer and hereditary diseases. In 1982 Ukraine published data of foreign authors proving the dangerous influence of radiation on the health of pregnant women and children, specifically mentioning children with inborn defects born of irradiated parents.

Before the Chornobyl catastrophe, in 1985, academician Valeri Legasov argued that the residual radioactivity after nuclear plant explosions increases with time because of accumulation of long-lived radionuclides. Alice Stuart, an expert on the effects of low levels of radiation, studied the state of health of the employees of the Hanford military plant, and victims of nuclear bombing in Japanese cities, and proved that small doses of radiation over a longer period of time are more of a carcinogenic threat than a one-time equivalent.

Are the restless experts of the International Atomic Energy Agency (IAEA) aware of this? Do they understand that this danger of long-time effect of low levels of radiation is the terrible “tail” that an explosion of a nuclear reactor leaves behind, causing new cases of serious diseases. This question found an answer in 1959, when the IAEA and the World Health Organization concluded a secret agreement not to disseminate data concerning the consequences of accidents at nuclear power plants for people’s health if these data contradicted the interests of the IAEA. The goal of the IAEA is to impose on the public the opinion that nuclear energy is safe, develop it in the world, and receive big money for its needs. Therefore, the thesis on the safety of small quantities of radiation has been repeated under cover of the UN.

Nowadays, cesium-137 is the main dose-forming radioactive nuclide that the Chornobyl explosion left us with. The contribution of strontium-90 to the total level of radiation is somewhat lower, while those of plutonium and americium are very small. Scientists forecast that 30 years after the catastrophe the cesium-137 soil contamination level will halve because of the natural decay of this isotope’s nuclei. And only in 300 years will this indicator fall under 37 kilobecquerels per square meter, except for the 30-kilometer zone around the Chornobyl Nuclear Power Plant and isolated spots in Polissia, where the contamination level is the same as in the exclusion zone.

These lands will become safe in terms of radiation only much later. A similar situation is with strontium-90: the periods of its half-decay are nearly the same (30 and 29 years, respectively). Since these radionuclides are quite mobile, their movement in the ground and the consequences of their migration are hard to predict. And plutonium, unlike previous isotopes, is hardly absorbed by plants, so it does not get into the human organism in any significant amounts through the nutrition chain. This highly toxic substance barely migrates in the ground, remaining on the place of the radioactive cloud fallout.

At the same time, plutonium-241 will “leave the arena” in a century — it will be replaced by more mobile “long-lived” americium-241. Experts are afraid that this isotope, able to percolate into the ground, will contaminate the subsoil waters and will spread from the worst contaminated zone to clean territories over several thousands of years.

It is worth analyzing the problem of our population’s health. The greatest harm to people’s health was done by the absolute passiveness of the leaders, whose official duties included protection of the population in extreme circumstances. The “fathers” of the Chornobyl Nuclear Power Plant and the nuclear city Prypiat did not dare to warn people about the danger and start an immediate evacuation without Moscow’s permission, and wasted many hours in order to contact it.

It is known that the population could have been saved from the radioactive iodine quickly and efficiently using pills that contain non-radioactive isotope. Filling the thyroid, the non-harmful iodine would have blocked the accumulation of radionuclides in this sensitive and important organ. The state leaders did not do anything to protect the population, and later explained their inaction by reluctance to spread panic. The iodine protection was applied only beyond Ukraine and the USSR: in Poland, Sweden, Germany, and other countries. The timely warning of the population about the ecological situation linked to the disaster at the Chornobyl Nuclear Power Plant would not have provoked panic. Rather it would have spared thousands of people dozens of unnecessary rems.

The fact that the Chornobyl catastrophe was a direct result of human activity makes us once again analyze its causes and aftermaths and seek answers to a never ending string of questions. The average longevity in Ukraine has been decreasing not because the Chornobyl disaster occurred, but because under the given circumstances the government was not able to take into consideration the new factors in order to minimize all possible risks. If everyone involved in governing the state were able to recognize these risks, we would have a better situation now.