Title: 1986
Content:  company. ; April 26 – Chernobyl disaster: A mishandled safety test at the Chernobyl Nuclear Power Plant in Pripyat, Ukrainian SSR, Soviet Union "killed at least 4,056 people and damaged almost $7 billion of property". Radioactive fallout from the accident is concentrated near Belarus, Ukraine and Russia and at least 350,000 people are forcibly resettled away from these areas. After the accident, "traces of radioactive deposits unique to Chernobyl were in nearly every country in the northern hemisphere". ; April 27 – "Captain Midnight" interrupts the HBO satellite feed. ; April 29 – The Diamond Jubilee of Hirohito is held at the Kokugikan in Tokyo. 
Title: Individual involvement in the Chernobyl disaster
Content:  The Chernobyl disaster was a catastrophic nuclear disaster that occurred in the early hours of 26 April 1986, at the Chernobyl Nuclear Power Plant in Soviet Ukraine. The accident occurred when Reactor Number 4 exploded and destroyed most of the reactor building, spreading debris and radioactive material across the surrounding area, and over the following days and weeks, most of mainland Europe was contaminated with radionuclides that emitted dangerous amounts of ionising radiation. On the night of April 25th and the early hours of April 26th, there had been 160 personnel on duty across the facility, while 300 more workers were on site at the building site of reactors 5 and 6.
Title: Nuclear safety and security
Content:  The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine. An explosion and fire released large quantities of radioactive contamination into the atmosphere, which spread over much of Western USSR and Europe. It is considered the worst nuclear power plant accident in history, and is one of only two classified as a level 7 event on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster). The battle to contain the contamination and avert a greater catastrophe ultimately involved over 500,000 workers and cost an estimated 18 
Title: Chernobyl disaster
Content:  The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the No. 4 reactor in the Chernobyl Nuclear Power Plant, near the city of Pripyat in the north of the Ukrainian SSR in the Soviet Union. It is considered the worst nuclear disaster in history both in cost and casualties. It is one of only two nuclear energy accidents rated at seven—the maximum severity—on the International Nuclear Event Scale, the other being the 2011 Fukushima Daiichi nuclear disaster in Japan. The initial emergency response, together with later decontamination of the environment, involved more than 500,000 personnel and cost an estimated 18 billion Soviet rubles—roughly 
Title: Karl Heinz Beckurts
Content:  In April 1986, the Chernobyl disaster occurred in the former Soviet Union. It was the worst to date and most consequential accident in the history of nuclear power. Since it also occurred in the middle of a heated political debate over nuclear power in West Germany, it has been speculated that the RAF wanted to win sympathy from the West German anti-nuclear movement against nuclear use.
Title: Chernobyl disaster
Content:  down, an uncontrolled nuclear chain reaction began, releasing enormous amounts of energy. The core melted down and two or more explosions ruptured the reactor core and destroyed the reactor building. This was immediately followed by an open-air reactor core fire. It released considerable airborne radioactive contamination for about nine days that precipitated onto parts of the USSR and Western Europe, before finally ending on 4 May 1986. Some 70% of fallout landed in Belarus, 16 km away. The fire released about the same amount of contamination as the initial explosion. As a result of rising ambient radiation levels off-site, a 10 km radius exclusion zone was created 36 
Title: Chernobyl
Content:   On 26 April 1986, one of the reactors at the Chernobyl Nuclear Power Plant exploded after unsanctioned experiments on the reactor by plant operators were done improperly. The resulting loss of control was due to design flaws of the RBMK reactor, which made it unstable when operated at low power, and prone to thermal runaway where increases in temperature increase reactor power output. Chernobyl city was evacuated nine days after the disaster. The level of contamination with caesium-137 was around 555 kBq/m2 (surface ground deposition in 1986). Later analyses concluded that, even with very conservative estimates, relocation of the city (or of 
Title: Chernobyl
Content:   Chernobyl (,, Чернобыль), also known as Chornobyl (Чорнобиль; Czarnobyl), is a partially abandoned city in the Chornobyl Exclusion Zone, situated in the Vyshhorod Raion of northern Kyiv Oblast, Ukraine. Chornobyl is about 90 km north of Kyiv, and 160 km southwest of the Belarusian city of Gomel. Before its evacuation, the city had about 14,000 residents, while around 1,000 people live in the city today. First mentioned as a ducal hunting lodge in 1193, the city has changed hands multiple times over the course of history. Jews were introduced to the city in the 16th century, and a now-defunct monastery was established near the city in 1626. By the end of the 18th century, Chornobyl 
Title: Nuclear power debate
Content:  The Chernobyl steam explosion was a nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine. A steam explosion and graphite fire released large quantities of radioactive contamination into the atmosphere, which spread over much of Western USSR and Europe. It is considered the worst nuclear power plant accident in history, and is one of only two classified as a level 7 event on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster). The battle to contain the contamination and avert a greater catastrophe ultimately involved over 500,000 workers and cost an estimated 18 billion rubles, crippling the Soviet economy. The accident raised concerns about the safety of the nuclear 
Title: Nuclear power in Ukraine
Content:  occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine. An explosion and fire released large quantities of radioactive contamination into the atmosphere, which spread over much of Western USSR and Europe. It is considered the worst nuclear power plant accident in history, and is one of only two classified as a level 7 event on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster). The battle to contain the contamination and avert a greater catastrophe ultimately involved over 500,000 workers and cost an estimated 18 billion rubles, crippling the Soviet economy. Ukraine used to receive its nuclear fuel exclusively 

Question: what happened at chernobyl?
Answer: Nuclear accident.