The Chernobyl disaster was a catastrophic nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine, which was under the direct jurisdiction of the central authorities of the Soviet Union. The Chernobyl disaster is the worst nuclear power plant accident in history in terms of cost and resulting deaths, and is one of only two classified as a level 7 event (the maximum classification) on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster in 2011). Photo: Graffiti of a crying baby on a wall, Chernobyl Power Plant, Chernobyl, Ukraine. (Photo by Hans Neleman/Getty Images)

In this photo taken Tuesday, June 23, 2015, a Ukrainian serviceman from the Kiev-2 volunteer battalion fires an weapon at a frontline in the village of Krymske, east Ukraine. Few places along the front line in east Ukraine see regular fighting as bitter as the village of Krymske. For now, Krymske is in the hands of Ukrainian government forces and the volunteer battalions that fight alongside them. (Photo by Evgeniy Maloletka/AP Photo)

A young woman holds a weapon during a basic combat training for civilians, organized by the Special Forces Unit Azov, of Ukraine's National Guard, in Mariupol, Donetsk region, eastern Ukraine, Sunday, February 13, 2022. The United States is evacuating almost all of the staff from its embassy in Kyiv as Western intelligence officials warn that a Russian invasion of Ukraine is increasingly imminent. (Photo by Vadim Ghirda/AP Photo)

A participant takes part in a “Zombie Walk” parade in Kiev, Ukraine on October 27, 2018. (Photo by Gleb Garanich/Reuters)

A couple embraces at the railway station in Kramatorsk, on May 20, 2023, amid the Russian invasion of Ukraine. (Photo by Sergey Shestak/AFP Photo)

A Ukrainian serviceman kisses his partner at the train station in Kramatorsk, Ukraine, Thursday, March 23, 2023. (Photo by Evgeniy Maloletka/AP Photo)

An Ukrainian serviceman caresses a cat near Bachmut, on March 23, 2023, amid the Russian invasion of Ukraine. (Photo by Aris Messinis/AFP Photo)

Vitali Klitschko of Ukraine poses in front of Odlanier Solis of Cuba during the weigh in at Sport Karstadt on March 18, 2011 in Cologne, Germany. The WBC World Championship Heavyweight fight between Vitali Klitschko of Ukraine and Odlanier Solis of Cuba will be held on 19 March 2011.