Nuclear analyst Joe Cirincione discusses the worst-case scenario for the nuclear crisis in Japan.
Energy Secretary Steven Chu on preventing a nuclear meltdown and whether U.S. plants can withstand natural disasters.
Dr. James Acton says a Chernobyl-like explosion at one of Japan's nuclear energy plants is "unbelievably unlikely."
Japan's ambassador to the U.S., Ichiro Fujisaki, talks about his country's fragile nuclear facilities.