Nuclear countries glean lessons from Japan's disaster

could be more than 10,000 dead and raced to bring food and clean water to more than 500,000 people who lost their homes in the quake and tsunami, rapidly deteriorating conditions inside Fukushima have threatened a meltdown with the potential to spread radioactive particles across the country and beyond.

“They might have been prepared for an earthquake. They might have been prepared for a tsunami. They might have been prepared for a nuclear emergency, but it was unlikely that they were prepared for all three,” said Ellen Vancko, an electric power expert with the Union of Concerned Scientists.

Before last week, Japan’s fifty-five 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.

Nuclear power plants stop if they do not 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 (NRC) 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.”

The threat for the Fukushima plant, 400 kilometers (250 miles) northeast of Tokyo, is compounded, experts say, by the design of its 40-year-old reactors, known in the industry as the General Electric Mark 1.

Unlike newer models, the Tokyo Electric reactors in Fukushima each contain an upper chamber for storing spent fuel rods in a pool of water housed together in the same concrete shell as the active core of the reactor. A failure in one can lead to problems in the other.

On Saturday morning, Japanese officials reported increased pressure inside number 1 reactor. A few hours later, there was an explosion in one of the reactors.

TEPCO, the plant operator, said it had detected increased radioactivity levels around the plant but that the reactor’s primary containment vessel had not been breached and no major leakage had occurred.

The company said it was about to begin pumping sea water into the reactors.