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The Chernobyl Tragedy

The Chernobyl tragedy was the deadliest accident in nuclear power generating history, which happened in 1986 at the Chernobyl nuclear power facility in the Soviet Union. In the history of commercial nuclear power, the Chernobyl tragedy was a singular occurrence and the only accident in which radiation-related fatalities had occurred.

The Chernobyl Power Complex, which is located about 20 kilometers south of the Belarusian border and roughly 130 kilometers north of Kiev, Ukraine, is comprised of four nuclear reactors of the RBMK-1000 type. The station featured four reactors that could each generate 1,000 megawatts of electricity, and it had been operational from 1977 and 1983.

Photo credit-world-nuclear.org


What went wrong?

The incident happened during a safety test designed to evaluate the steam turbine's capacity to run the emergency feedwater pumps of an RBMK-type nuclear reactor in the case of a severe coolant leak and simultaneous loss of external power. The operators mistakenly reduced power output to almost nil during a scheduled reactor power reduction in preparation for the test, in part because of xenon poisoning. The operators removed a number of control rods that exceeded operating procedure limitations while they stabilized the reactor and recovered from the power outage. When the test was finished, the operators started the reactor shutdown.

This action led to localized increases in reactivity within the reactor as a result of a design defect. As a result, the fuel tubes ruptured, causing a quick drop in pressure that led the coolant to flash into steam. Due to the reduced neutron absorption, the reactor's activity increased, which further raised the temperature of the coolant (a positive feedback loop). Steam explosions and the melting of the reactor core were the results of this process. The nuclear core was damaged during the meltdown, and the reactor building was completely destroyed. Immediately after that, an open-air reactor core fire broke out, lasting until May 4 of that same year, during which time airborne radioactive pollutants were discharged and spread over the USSR and Europe.


How was it controlled?

Helicopters were utilized by emergency personnel reacting to the disaster to apply sand and boron on the reactor debris. The boron was used to block further nuclear reactions, while the sand was used to put out the fire and prevent more radioactive material emissions. To prevent future radioactive material escape, the technicians entirely enclosed the damaged unit in a temporary concrete construction termed the "sarcophagus" a few weeks after the accident. To lessen radioactive contamination at and around the facility, the Soviet administration also cleared and buried nearly a square mile of pine forest close to the plant. The last reactor at Chernobyl shut down in December 2000 after three others were restarted and finally shut down permanently.


What were the effects of the tragedy?

Several times more radiation than that produced by the atomic bombs fired on Hiroshima and Nagasaki, Japan, was released into the atmosphere, with between 50 and 185 million curies of radionuclides (radioactive forms of chemical elements) escaping into the environment. Over Belarus, Russia, and Ukraine, this radioactivity was carried by the wind and quickly made its way as far west as France and Italy.

Water bodies in the area, including rivers, lakes, and the flora and wildlife, were impacted. Along with adiabatic precipitation, the entire human food chain was impacted in countries like Norway and the UK. Humans were affected by the disaster physically as well as psychologically, including traumatic syndromes and depression. Following decontamination and other problems, the Soviet Union incurred significant expenses. They had a significant socioeconomic influence.


Scientists predict that the area around the former plant won't be livable for up to 20,000 years.

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