The Chernobyl disaster was a nuclear meltdown that occurred on April 26, 1986, in the No. 4 light water graphite moderated reactor at the Chernobyl Nuclear Power Plant near Pripyat, in what was part of the Ukrainian Soviet Socialist Republic of the Soviet Union.
During a late-night safety test which simulated a station power failure in which safety systems were deliberately turned off, a combination of inherent reactor design flaws and the reactor operator negligence resulted in uncontrolled reactor conditions. Water flashed into the steam-generating a steam explosion and graphite fire. The fire produced updrafts and toxic plumes were sent into the atmosphere. The radioactive material became a fall-out precipitate over large tracts of western USSR and Europe.
The Chernobyl disaster was the worst nuclear power accident in history, both in terms of cost and casualties. It is one of only two nuclear energy accidents classified as a level 7 event, the maximum classification, on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster in Japan in 2011).
The initial evidence that a major release of radioactive material was affecting other countries was announced by Sweden. Workers from the Forsmark Nuclear Power Plant, about 680 miles from the Chernobyl site, were found to have radioactive particles on their clothes. After searching for the source of the radioactivity and determining that there was no leak at the Swedish plant on April 28, the disaster was determined to have come from the Soviet Union.
It has been approximated that about 400 times more radioactive material was released from Chernobyl than by the atomic bombing of Hiroshima. By contrast, the Chernobyl accident released about one hundredth to one-thousandth of the total amount of radioactivity released during the era of nuclear weapons testing.
According to Mikhail Gorbachev, the Soviet Union spent 18 billion rubles (equivalent to 18 billion USD at the time) on containment and decontamination, virtually bankrupting itself. In Belarus alone, the total cost over 30 years is estimated at $302 billion. 5-7% of all government spending in Ukraine is still related to the Chernobyl disaster. Much of the current costs are related to the payment of Chernobyl-related social benefits to over 7 million people across three different countries.
August 1989: Demonstrators in Kiev demand that the government makes public the secret Chernobyl documents. One banner reads: “We demand a Nuremberg trial for Chernobyl.” Many of the regions affected are represented by their national flags, such as the green flag of Belarus, the blue and yellow flag of the Ukraine and Russian tricolor Photograph: Igor Kostin/Corbis1992: The evacuated city of Pripyat. Before the disaster, it housed 47,000 inhabitants, including 17,000 children. Due to its contamination by plutonium isotopes, Pripyat cannot be inhabited for another 24,000 years. It was built to house Chernobyl workers in the 1970s and was one of the “youngest” towns in the USSR with an average age of 26. Other unofficial evacuations also took place including in Kiev, where children were reported to have been put on trains in great numbers Photograph: Igor Kostin/CorbisGraffiti near Frankfurt, Germany, reads Oh God, it rains above the symbol for radioactivity on the wall of a house on May 5, 1986. FRANK RUMPENHORST:APDecember 1989- Contaminated apples hang unharvested from a tree within the 30km no-go area around the nuclear site, three years after the explosion Photograph- Igor Kostin: Corbis1992- A villager who refuses to leave her home within the no-go area continues to live off the land, despite a high concentration of radioactive cesium-137 in the soil Photograph- Igor Kostin: CorbisA raven stretches its wings as it sits on a post inside the 30 km (18 miles) exclusion zone around the Chernobyl nuclear reactor near the village of Babchin, Belarus on December 23, 2009. The sign reads- Radiation hazard.5 August 1986: A blood test is conducted on a living reindeer in the Swedish Alps to measure the cesium level in the animal. Thousands of reindeer were slaughtered after Swedish authorities discovered a dangerous level of cesium in the animals, brought about by the reindeer’s’ feed being contaminated by fallout from radioactive clouds Picture: HAKAN LINDGREN/AFP/Getty ImagesA deformed corpse of a stillborn piglet on a farm close to the Chernobyl reactor after the disaster is on display in the Chernobyl Museum in Kiev, Ukraine, in November 1995. MARTIN GODWIN: GETTY IMAGESA woman holds a disabled newly born pig, a victim of the radioactivity fallout from the Chernobyl power plant accident, on Oct. 2, 1989. LARS GRANDSTRAND: AFP: GETTY IMAGESUkrainian Academy of Sciences member Vyacheslav Konovalov holds a preserved mutated colt in Zhytomyr, Ukraine, on Monday, March 11, 1996. Konovalov had been studying biological mutations appearing after Chernobyl nuclear plant explosion. The colt was dubbed “Gorbachev colt” after Konovalov brought a life-size photo of it to the Supreme Soviet in 1988 to show the Soviet President Mikhail Gorbachev what Chernobyl was doing the country’s wildlife. AP Photo/Efrem LukatskyA wolf stands in a field inside the exclusion zone around the Chernobyl nuclear reactor near the village of Babchin, Belarus on February 1, 2008. Wildlife in the exclusion zone has been teeming despite radiation since people left the area around Chernobyl after the 1986 nuclear disaster, keepers of the ecological reserve said. Reuters/Vasily FedosenkoUkrainian school children try on gauze masks as part of a safety drill in a school in Rudniya, just outside the Chernobyl contamination zone, Monday, April 3, 2006. PinterestA guide holds a Geiger counter showing radiation levels 37 times higher than normal as a woman takes a picture in front of the sarcophagus of the destroyed fourth block of the Chernobyl nuclear power plant on September 16, 2010. Thousands of people each year visit the Chernobyl nuclear power plant, where the world’s worst nuclear disaster took place in April 1986, and the 30-km zone around it that remains uninhabited. GENYA SAVILOV/AFP/Getty ImagesThis unlocated picture shows a disabled child playing on Aug. 4, 1992. Some 150,000 people, including 60,000 children, were affected by radioactive dust from the Chernobyl power plant accident, according to a report presented to the European Parliament in 1992. TIMUR GRIB/AFP/GETTY IMAGESNastya Dolgovevets, a 2-year-old from the Slutsk village in the Minsk region of Belarus, sits on her bed on Aug. 16, 1996, at the Children’s Division of the Oncology Research Institute in Minsk, Belarus. She has been diagnosed with a left wrist tumor. The marks on her head were from iodine that the doctors used to cover up little spots that were beginning to appear on her body that they were unsure what they were from. Fire from the Chernobyl nuclear plant explosion burned out of control for five days, spewing more than 50 tons of radioactive fallout across Belarus. The government denied the accident happened for several days, allowing the people in the Gomel region of Belarus to linger in the radiation. EZRA SHAW/GETTY IMAGES