The Chernobyl tragedy

The Chernobyl tragedy was a catastrophic nuclear accident that occurred on April 26, 1986 in reactor No. 4 of the
Chernobyl Nuclear Power Plant near the city of Pripyat in the north of the Ukrainian SSR.
The accident occurred during an inappropriately controlled test of the same RBMK reactor type with untrained personnel. It was designed with built-in security flaws that were deliberately ignored when they emerged over the years.


The test was a power outage simulation with the goal of establishing a safety procedure to keep the reactor coolant circulating until the emergency generators could provide power. This interval was about 1 minute and was determined to be a potential safety issue that could cause the core to overheat. Since 1982, three such tests have been conducted, but the solution was not fully provided. Unfortunately, this fourth test was delayed by 10 hours and the staff specially trained for the test procedure was replaced by another staff. The test controller then failed to follow the test procedure, which, along with internal RBMK reactor design flaws and the deliberate deactivation of several emergency safety systems, created an indecisive operating condition that resulted in an uncontrolled nuclear chain reaction.


At the time of the test, the power level of the reactor was supposed to be in the range of 700-1000 watts. However, the test procedure staff lowered this level to 200 watts, and suddenly a large amount of power was lost, vaporizing the superheated cooling water, the reactor pressure vessel .became an instant open-air reactor. detonated in a highly destructive steam explosion followed by its core fire.

The total number of injured remains a matter of dispute. Estimates of the death toll from the radiation released range from 4,000 in a UN study to 200,000 in a Greenpeace study. During the accident, the effects of the steam explosion caused 2 deaths at the site: one immediately after the explosion, the other from a fatal dose of ionizing radiation. Over the following days and weeks, 134 soldiers, 28 firefighters, and workers were hospitalized with acute radiation syndrome, who died within months. Additionally, among this group of 134 hospital survivors, approximately 14 radiation-related cancer deaths followed over the next 10 years. Among the broader population, Since 2011, 15 childhood thyroid cancer deaths have been documented. Additional time and research is needed to determine the likely cancer risk among surviving workers, among those hospitalized with ARS at baseline, and among the larger population.