Where was the worst nuclear accident since Chernobyl produced in 2011?

The Great East Earthquake occurred at 2:46pm on March 11th recorded magnitude 9.0, has given tremendous damage to the northern part of Japan, especially in the prefectures of Fukushima, Miyagi and Iwate. The earthquake and tsunami triggered the worst nuclear accident since Chernobyl. The Fukushima Daiichi nuclear power station located in the Pacific Ocean coast received huge damage by the earthquake and tsunami. The piping facility in the building, the facilities for the external power supply and backup power were destroyed. The next day, 12th in the early morning, the leakage of radioactive materials had been found in front of the main gate of the nuclear power plant. The steam was filled in the building by the core melt down caused by the dysfunction of the cooling system.