Japan's nuclear officials have doubled their estimate of the radiation that escaped from the Fukushima nuclear plant in the first week after the country's March 11 earthquake and tsunami, raising the level from 370,000 terabecquerels to 770,000 terabecquerels. The BBC explains that while the amount is only 15 percent of the total released during the world's worst nuclear disaster--Chernobyl in 1986--the revision indicates that the contamination near the plant is worse than originally thought and will likely lead to more criticism of the plant's operator and the government for not releasing information quickly enough during the crisis. The officials also revealed that meltdowns occurred in three reactors more quickly than previously thought.

In another report submitted to the International Atomic Energy Agency today, Japan admitted that it was unprepared for a severe nuclear accident, promising to create an independent nuclear power regulator (the country's nuclear safety agency is now part of the government) and overhaul its nuclear safety standards.