Chernobyl 25 years ago; radioactive Cesium 137 cloud over Russia and Europe

25 years ago, on 26 April 1986, a nuclear power plant catastrophe took place in Chernobyl, near Kiev, in the Ukraine. It was the worst nuclear power plant accident in history. The accident was the result of a flawed reactor design that was operated with inadequately trained personnel. Ironically, the disaster occurred during a systems safety test performed to test whether the reactor had the capability to ride through the first 60--70 seconds of a total loss of electric power during an emercengy shutdo