Nuclear authorities had earlier warned that the Fukushima No 1 plant, located about 250km northeast of Tokyo, an urban area of 30 million people, "may be experiencing a nuclear meltdown".
The plant's cooling system was damaged in the quake that hit yesterday, leaving the government scrambling to fix the problem and evacuate more than 45,000 residents within a 10km radius.
Public broadcaster NHK today said that a blast had been heard at about 3.30pm local time and showed delayed footage of smoke billowing from the site, also reporting that the reactor building had been destroyed.
TV channels warned nearby residents to stay indoors, turn off air-conditioners and not to drink tap water. People going outside were also told to aviod exposing their skin and to cover their faces with masks and wet towels.
Read more: http://www.news.com.au/breaking-news/japans-fukushima-no1-nuclear-power-plant-explodes/story-e6frfku0-1226020387955#ixzz1GRHYYrl6