The Chernobyl Nuclear Power Plant underwent a level 7 event - the worst accident so far. The plant, located in the Soviet Union near Pripyat in Ukraine lost its number four reactor on 26 April 1986. A link to the Wikipedia article on the accident is provided.
Worst reactor accident to that date. The Japanese 2011 accident may turn out to be worse however.
Three mile island was the site of the worst nuclear 'accident' in america's history. The reactor went into meltdown - releasing radioactive material into the atmosphere.
What exactly constitutes the single "worst" trucking accident in Canadian history is subjective. However, a compilation of some of the worst truck accidents can be found on YouTube.
The answer your probably looking for is 'melt down' however a melt down is a very rare event and the worst form of 'nuclear accident'.
The #4 reactor is the reactor at the Chernobyl Nuclear Power Plant (Pripyat, Ukraine) that exploded on April 26, 1986. It is still the worst nuclear accident to ever take place anywhere.
The worst railroad accident to ever have occurred in the United States of America was the Great Train Wreck of 1918. It is considered to be the worst accident in American history.
The Chernobyl nuclear accident.
The worst aircraft accident in history was definitely, in my opinion, the Tenerife airport disaster. It was very morbid what with all the deaths. Want more info? Go to wikipedia and search it.
A long time ago in a galaxy far far away...
Three Mile Island, Pa, 1979
The 1986 accident at the Chernobyl nuclear power plant in Ukraine is the only accident in the history of commercial nuclear power to cause fatalities from radiation. It was the product of a severely flawed Soviet-era reactor design and human error.