This is the explanation video about the chain of events which have caused nuclear reactor problems in Fukushima Nuclear Power Plant in Japan.
These problems were caused by earthquake and following tsunami near to Sendai town in north-east of Tokyo (http://en.wikipedia.org/wiki/2011_Sendai_earthquake_and_tsunami ).
Here is the original source:
http://edition.cnn.com/video/#/video/world/2011/03/14/dnt.japan.reactor.explainer.nhk?hpt=C2
