The Chernobyl Accident, 1986

Background 

On the 26th of April 1986, Ukraine would experience one of the most destructive nuclear disasters of all time. The result of machine technical flaws and poorly trained staff, the disaster was also a consequence of politics: occuring at the height of Cold War tensions between the Eastern Bloc (the Soviet Union and its allies) and the Western Bloc (the United States and its allies), the Soviets were eager to conceal their military and scientific strategies away from their political enemies, of whom they suspected employed spies in a bid to steal confidential information and gain total global supremacy. 

This meant that, in the absence of shared technological advancements, the Soviets were woefully behind the rest of the world in providing safety measures to their machines and implementing an already established global culture of factory worker safety within their industrial sectors. Situated 65 miles north of the capital Kyiv and atop the Pripyat settlement [1], the Chernobyl 4 reactor within the Chernobyl Power Plant exploded in a steam reaction, killing approximately 30 people in the span of 3 months [2], inflicting radiation poisoning onto 134 victims [3], and releasing the largest amount of radioactive materials into the environment for any industrial operation in recorded history. 

1:23:45 am 

The very first Soviet power plant, the Chernobyl Power Plant consisted of 4 major RBMK-1000 Soviet style “graphite-moderated, direct-cycle” [4] nuclear reactors. The exothermic reaction of atomic fission (the splitting of atoms) produced heat that would boil water pumped to the bottom of the fuel channels and generate pressurized steam. The steam in turn would be guided along the reactor’s internal system to move turbine blades, resulting in a maximum capacity of 1,000 megawatts (MW) [5] of electrical power that would be used to supply major infrastructure. At the centre of reactor 4 was a core made of uranium, a highly radioactive element. he purpose of it was to hold uranium dioxide fuel to speed up the reaction. The very reactivity of each reactor could be controlled through 211 [6] separate control rods that had the ability to raise or lower the rate of the reaction via absorption due to the splitting of neutrons (thus preventing further atomic fission). Additional water was used to surround and cool the nuclear reactor uranium core, with a special refuelling machine being brought in at times to change the fuel bundle without properly shutting the reactor down; a result of the communist ideal to maximise industrial productivity at all costs. 

In the early hours of April 26, 1986 several factory workers decided to conduct a separate test on reactor 4’s turbines that could spin and supply electrical energy to the 2 main cooling pumps in the absence of power from the main electrical power source. 

Due to the lack of safety measures, such a test did not require external approval from officials such as the factory’s nuclear regulator or chief design authority for the reactor (NIKET). As part of preparations, the emergency core cooling system was disabled 11 hours beforehand at 14:00 the previous day; allowing the reactor to operate for so long without the feature did not directly influence the accident but indicated the factory’s overall casual stance towards safety measures. While unwilling to use steam within their experiment, the operators were hesitant to pause the main reaction and decrease electrical production for their consumers. 

At 01:23, the experiment began with immediate dire consequences. The test led to a lack of cooling water surrounding the core of the reactor. From this, the surge of energy due to the nuclear fission reaction was met with no controlled resistance. The combination of intense fuel with very little cooling water caused the uranium dioxide to fragment, rapidly increasing steam- and therefore pressure- within reactor 4. The immense pressure lifted the 1,000 t [7] roof of Chernobyl 4 from its initial position, dismantling all 211 control rods. The isolated emergency cooling circuit ( disabled earlier) exploded, leading cold water to submerge the highly reactive uranium core, conceding in a major steam explosion that released fission products into the air. A second explosion soon followed, believed to be caused by the production of hydrogen gas (another highly reactive element) due to the various interactions of steam with zirconium from already exploded parts of the core. 

Aftermath 

Two workers immediately died as a result of the explosions. Graphite that initially surrounded the nuclear core mixed with the fuel within, beginning a series of fires that lasted 10 days and would be the main transmitters of radioactivity into the atmosphere. Chemically inert substances such as boron and clay would be air-dropped via helicopter by the second day in an effort to extinguish the flames: they would, however, last more than a week and release radioactive particles iodine-131 and cesium-137. This resulted in extreme cases of Acute Radiation Syndrome (ARS) within civilians of the immediate area and depositing radioactive material as far as other parts of Ukraine, Russia and Belarus. 

By July 1986, approximately 30 people, including 6 firefighters, were determined to have died due to radiation poisoning; many victims suffered extensive burns, fever and confusion. With lethal doses of radiation generally spanning 8,000-10,000 miligrays (mGy) [8], the deceased firefighters were found to have absorbed an estimated 20,000 mGy. An estimated 200,000 from all over the USSR would help in the cleaning of the site between 1986-87, and while many of them would be exposed to small radiation doses, those onsite in the immediate aftermath received 10,000 mGy [9].

The town of Pripyat in which Chernobyl was home to was immediately evacuated by authorities by April 27, with 45,000 [10] people being forced to flee for their own safety. By the 14th of May, however, an estimated 1,000 [11] had returned to live despite the danger of contamination. In the years to follow, about as many as 200,000 [12] were compelled to resettle in less contaminated areas outside the exclusion zone of 1,017 [13] square miles around the plant. 

In February 2003, the Chernobyl Forum was established by the International Atomic Energy Agency (IAEA) with the support of the United Nations, Ukrainian, Belarussian, and Russian Federation authorities [14]. Two reports on the incident were conducted on separate aspects, with “Environment” by the IAEA and “Health” [15] by the UN’s World Health Organisation, with both undergoing intensive peer-reviewing and discussion to ensure an accurate portrayal of the accident. The reports concluded that civilians adopted a psycho-social attitude of fatalism due to misconceptions about the effects of radiation: many believed themselves to be ill, taking “on the role of invalids” while receiving very little exposure to hinder their well-being [16]. 

 Unfortunately, an estimated 1 million abortions [17] are believed to have been conducted out of fear of birth defects, with many of them being advised by physicians in eastern Europe ignorant of global knowledge on the effects of radiation exposure on pregnancy. 

After the collapse of the USSR in 1990, about $400 [18] million was invested into the improvement of Chernobyl reactors 1,2 and 3, updating safety measures to the global standards and ensuring workers would be exposed to a level of radiation below the international limit. The Convention on Nuclear Safety, which aims to enforce high safety measures onto the 29 countries operating a total of 437 plants [19 ], was established by the IAEA in 1996. 

Former Chernobyl locals and factory workers live in the nearby town of Slauvitch, 18 miles from the site [20 ]. On the 31st March 2022, the control of the site was returned to Ukraine by Russia during the Russo-Ukrainian War (2014-present). 

Bibliography

[1] Britannica. “Chernobyl Disaster | Causes & Facts.” Encyclopædia Britannica, Britannica, 2 Jan. 2019, www.britannica.com/event/Chernobyl-disaster.

[2] “Chernobyl Accident 1986 - World Nuclear Association.” World-Nuclear.org, 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident#progressive-closure-of-the-chernobyl-plant.

[3] “Chernobyl Accident 1986 - World Nuclear Association.” World-Nuclear.org, 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident#progressive-closure-of-the-chernobyl-plant.

‌[4] Garrick, B.J. “Chernobyl Nuclear Power Plant - an Overview | ScienceDirect Topics.” Www.sciencedirect.com, 2013, www.sciencedirect.com/topics/medicine-and-dentistry/chernobyl-nuclear-power-plant.

[5] Garrick, B.J. “Chernobyl Nuclear Power Plant - an Overview | ScienceDirect Topics.” Www.sciencedirect.com, 2013, www.sciencedirect.com/topics/medicine-and-dentistry/chernobyl-nuclear-power-plant.

[6] “Chernobyl Accident 1986 - World Nuclear Association.” World-Nuclear.org, 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident#progressive-closure-of-the-chernobyl-plant.

‌[7] “Chernobyl Accident 1986 - World Nuclear Association.” World-Nuclear.org, 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident#progressive-closure-of-the-chernobyl-plant.

[8]“Chernobyl Accident 1986 - World Nuclear Association.” World-Nuclear.org, 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident#progressive-closure-of-the-chernobyl-plant.

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[9]“Chernobyl Accident 1986 - World Nuclear Association.” World-Nuclear.org, 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident#progressive-closure-of-the-chernobyl-plant.

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[10]“Chernobyl Accident 1986 - World Nuclear Association.” World-Nuclear.org, 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident#progressive-closure-of-the-chernobyl-plant.

[11]“Chernobyl Accident 1986 - World Nuclear Association.” World-Nuclear.org, 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident#progressive-closure-of-the-chernobyl-plant.

[12]“Chernobyl Accident 1986 - World Nuclear Association.” World-Nuclear.org, 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident#progressive-closure-of-the-chernobyl-plant.

[13]“Chernobyl Accident 1986 - World Nuclear Association.” World-Nuclear.org, 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident#progressive-closure-of-the-chernobyl-plant.

[14] U.S. Government Accountability Office. “How Chernobyl Jump-Started the Global Nuclear Safety Regime.” Www.gao.gov, 12 Sept. 2019, www.gao.gov/blog/2019/09/12/how-chernobyl-jump-started-the-global-nuclear-safety-regime.

[15] U.S. Government Accountability Office. “How Chernobyl Jump-Started the Global Nuclear Safety Regime.” Www.gao.gov, 12 Sept. 2019, www.gao.gov/blog/2019/09/12/how-chernobyl-jump-started-the-global-nuclear-safety-regime.

‌[16] “Chernobyl Accident 1986 - World Nuclear Association.” World-Nuclear.org, 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident#progressive-closure-of-the-chernobyl-plant.

‌[17] World Nuclear Association. “Chernobyl Accident 1986.” World-Nuclear.org, World Nuclear Association, 26 Apr. 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident.

[18] “Chernobyl: A Site Transformed.” Www.ebrd.com, www.ebrd.com/what-we-do/sectors/nuclear-safety/chernobyl-overview.html.

[19 ] Office, U. S. Government Accountability. “Nuclear Safety: Convention on Nuclear Safety Is Viewed by Most Member Countries as Strengthening Safety Worldwide.” Www.gao.gov, www.gao.gov/products/gao-10-489.

[20 ] “Chernobyl Accident 1986 - World Nuclear Association.” World-Nuclear.org, 2024, world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident#progressive-closure-of-the-chernobyl-plant.