Shocking video of nuclear plant explosion

A second nuclear reactor at Japan's embattled Fukushima nuclear facility exploded about an hour ago, in a mushroom cloud of grey smoke. It is the second of as many as five troubled Japanese reactors to experience a hydrogran explosion since Friday's catastrophic earthquke -- in both cases Japanese officials claim that that the main reactor containment held, preventing a massive release of radiation,

That said, the New York Times is reporting U.S. military helicopters already detecting radiation as far as 60 miles from the stricken reactors. The video below shows the new explosion as it happened on live Japanese television.