Shirakawa, Japan (CNN) -- Japanese authorities are operatingon the presumption that possible meltdowns are under way at two nuclearreactors, a government official said Sunday, adding that there havebeen no indications yet of hazardous emissions of radioactive materialinto the atmosphere.
The attempts to avert a possible nuclearcrisis, centered around the Fukushima Daiichi facility in northeastJapan, came as rescuers frantically scrambled to find survivorsfollowing the country's strongest-ever earthquake and a devastatingtsunami that, minutes later, brought crushing walls of water that wipedout nearly everything in their paths.
Chief Cabinet SecretaryYukio Edano told reporters there is a "possibility" of a meltdown atthe plant's No. 1 reactor, adding, "It is inside the reactor. We can'tsee." He then added that authorities are also "assuming the possibilityof a meltdown" at the facility's No. 3 reactor.
A meltdown is a catastrophic failure of the reactor core, with a potential for widespread radiation release.