Japanese officials have reassured the public, saying there is no danger of a meltdown of the reactor core. But US nuclear experts say they are worried about the possibility.
Ken Bergeron, a physicist who formerly worked for Sandia National Laboratories, says a so-called station blackout - which involves the loss of both off-site electricity and on-site backup power from diesel generators - is viewed in the nuclear industry as extremely unlikely. But he says it happened.
"So we're in uncharted territory. We're in the land where probability says we shouldn't be. And we're hoping that all of the barriers to release of radioactivity will not fail," he said. Voice of America News.com