On April 26th, 1986, the world witnessed the most expensive accident in history. The Chernobyl disaster, widely considered to have been the worst nuclear power plant accident in history, and is one of the level 7 event (the maximum classification) on the International Nuclear Event Scale. The accident was officially attributed to power plant operators who violated plant procedures and were ignorant of the safety requirements needed.Chernobyl accident was considered the greatest socio-economic catastrophe recorded history. 50% part of Ukraine is influenced and contaminated. 200,000 people should be evacuated and transferred, while 1.7 million people directly affected by the disaster. The death victims attributed to Chernobyl, including those who died from cancer after years and years, about 125,000. Nobody knows exactly how much the world’s worst nuclear accident cost. $200 billion is considered a fairly conservative figure including cleaning, transmigration, and the compensation of victims. The cost of a new steel shelter for the Chernobyl nuclear plant will cost $2 billion alone.