Japan in nuclear crisis

(CNN) -- Workers continued efforts to cool down fuel rods inside two nuclear reactors Sunday as a Japanese government official warned that a second explosion could occur at the plant.

The aftermath of the devastating earthquake -- from the scores of casualties to the nuclear concerns at the plant in Fukushima prefecture -- marks the "toughest and most difficult crisis for Japan" since the end of World War II, Japanese Prime Minister Naoto Kan said Sunday.
Chief Cabinet Secretary Yukio Edano said an explosion could take place in the building housing the No. 3 reactor at the Fukushima Daiichi plant in northeastern Japan.

"There is a possibility that the third reactor may have hydrogen gas that is accumulating in the reactor (that) may potentially cause an explosion," he said.
An explosion caused by hydrogen buildup Saturday blew the roof off a concrete building housing the plant's No. 1 reactor, but the reactor and its containment system were not damaged in the explosion.

Edano said the No. 3 reactor would also likely withstand a similar blast, noting that workers had already released gas from the building to try to prevent an explosion.


Meanwhile, the prime minister ordered a Tokyo power company to conduct a widespread power outage in an effort to preserve energy as workers try to repair power plants damaged in the earthquake, including nuclear facilities.

The Tokyo Electric Power Company has been instructed to conduct three-hour rolling blackouts as the country faces a 10 million kilowatt shortage, officials said.

At the nuclear plant, workers have been scrambling to cool off fuel rods at both reactors after a massive earthquake and tsunami disabled their cooling systems. Japanese authorities have said there is a "possibility" that a meltdown has occurred in the reactors.
A meltdown is a catastrophic failure of the reactor core, with a potential for widespread radiation release.

But Japanese officials stressed that there were no indications of dangerously high radiation levels in the atmosphere around the two reactors at the Fukushima Daiichi nuclear plant in northeastern Japan. They said they were unable to confirm whether a meltdown had occurred because they cannot get close enough to the reactors' cores.

"We are continuing to monitor the radiation, but it is under control," Edano told reporters.