A meltdown could spread radioactive particles across Japan and Beyond

***Old Nuclear Plants Can't Just Be Abandoned*** "It's a problem they've gotten into now"

Before last week, Japan's 55 nuclear reactors had provided about 30 percent of the nation's electric power. That percentage had been expected to rise to 50 percent by 2030 with a boom in new plant construction.
But nuclear power plants stop if they don't have enough power. Stranded nuclear reactors cannot circulate water to cool their fuel rods. When the existing water boils off, the nuclear fuel begins to heat, a process that can set fire to surrounding materials and touch off powerful hydrogen blasts.

"Power is the lifeblood for a power plant," said Harold Denton, who headed the U.S. Nuclear Regulatory Commission team that handled the 1979 Three Mile Island crisis in the United States. "If you've got power, you can do a lot, but if you don't have any power, the water in the reactor vessels heats up and boils away and the fuel begins to melt. It's a problem they've gotten into now."

http://www.reuters.com/article/2011/03/17/us-japan-quake-meltdown-specialreport-idUSTRE72G65Z20110317