The Chernobyl disaster, also referred to as the Chernobyl accident, was a catastrophic nuclear accident. This accident was due to both human error and design flaw. The disaster occurred at 01.23 hour on Saturday, April 26 1986 when the fourth reactor at the Chernobyl power plant exploded during a systems test. The power plant is near the now-abandoned town Pripyat, in northern Ukrainian Soviet Socialist Republic, Soviet Union, approximately 104 km north of Kiev. A large amount of fire released radioactive contamination into the atmosphere and spread across USSR and Europe. The disaster was a unique industrial accident because of the scale of its social, environmental and economic impacts.