Chernobyl Chernobyl was the greatest nuclear disaster of the 20th century. On April 26th, 1986, one of four nuclear reactors located in the Soviet Union melted down and contaminated a vast area of Eastern Europe. The meltdown, a result of human error, lapsed safety precautions, and lack of a containment vessel, was barely contained by dropping sand and releasing huge amounts of deadly radioactive isotopes into the atmosphere. The resulting contamination killed or injured hundreds of thousands of people and devastated the environment. The affects of this accident are still being felt today and will be felt fo