Plume formation by meteorological conditions for instantaneous release on dates and times (GMT) indicated

The Soviet nuclear programme was run directly from Moscow, and the Ukrainian authorities received little information in the initial days following the disaster. The first public statement came on the day after it happened, after the Swedish authorities had publicly warned of a major nuclear accident in the Soviet Union. Within a few days, a special commission ordered the evacuation of a 30-kilometre zone around the plant. Some 600 000 specially trained staff, including 240 000 servicemen, were brought in from all over the Soviet Union to clean the zone; of them, 50 000 were ‘bio-robots’, tasked with removing the debris and building a sarcophagus-like structure to contain the reactor. This first sarcophagus was completed in December 1986. The Ukrainian authorities continued operating the three other reactors until 2000, when the government eventually shut down the plant. In 2013, after 600 square metres of the roof collapsed, the international community called for the construction of a new sarcophagus.