My Chernobyl Adventure part 2: Unfinished Reactor

Chernobyl ( /tʃərˈnoʊbɪl/; Russian: Чернобыль, pronounced [tɕɪrˈnobɨlʲ]) or Chornobyl (Ukrainian: Чорнобиль, pronounced [tʃɔrˈnɔbɪlʲ], Polish Czarnobyl) is an abandoned city in northern Ukraine, in Kiev Oblast, near the border with Belarus. The city had been the administrative centre of the Chernobyl Raion since 1932.

The Chernobyl disaster (locally Катастрофа Чернобыля, Chornobyl Catastrophe) was a nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine (officially Ukrainian SSR), which was under the direct jurisdiction of the central authorities in Moscow. 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.

The disaster began during a systems test on Saturday, 26 April 1986 at reactor number four of the Chernobyl plant, which is near the city of Prypiat and within a close proximity to the administrative border with Belarus and Dnieper river. There was a sudden power output surge, and when an emergency shutdown was attempted, a more extreme spike in power output occurred, which led to a reactor vessel rupture and a series of explosions. These events exposed the graphite moderator of the reactor to air, causing it to ignite. The resulting fire sent a plume of highly radioactive smoke fallout into the atmosphere and over an extensive geographical area, including Pripyat. The plume drifted over large parts of the western Soviet Union and Europe. From 1986 to 2000, 350,400 people were evacuated and resettled from the most severely contaminated areas of Belarus, Russia, and Ukraine. According to official post-Soviet data, about 60% of the fallout landed in Belarus.

The Chernobyl Nuclear Power Plant Exclusion Zone, which is sometimes referred to as the Chernobyl Zone, the 30 Kilometer Zone, the Zone of Alienation, or simply The Zone (Ukrainian official designation: Зона відчуження Чорнобильської АЕС, zona vidchuzhennya Chornobyl's'koyi AES, colloquially: Чорнобильська зона, Chornobyl's'ka zona оr Четверта зона, Chetverta zona) is the 30 km/19 mi exclusion zone around the site of the Chernobyl nuclear reactor disaster and is administered by a special administration under the Ukrainian Ministry of Emergencies. Geographically, it includes the northernmost raions (districts) of the Kiev and Zhytomyr Oblasts (provinces) of Ukraine, and adjoins the country's border with Belarus. A separately administered Belarusian zone continues across the border.