Reactor

For the better part of Sunday, media outlets in Japan and around the world carried scary-sounding news about radiation at the stricken Fukushima nuclear plant's No. 2 reactor. In a typical report, Japanese broadcaster NHK said: "Power company says it has detected radioactive materials 10 million times normal levels. " After nightfall came the mea culpa. There was a "mistake in the measurement of the assessment" of radiation in a building near the reactor, Tokyo Electric Power Co. said on its website.

Officials at Japan's stricken Fukushima Daiichi nuclear plant late Sunday retracted their announcement that they had found puddles at the facility's No. 2 reactor containing 10 million times more radioactivity than would be found in water in a normally functioning nuclear reactor. "The number is not credible," Tokyo Electric Power Co. spokesman Takashi Kurita, said, according to the Associated Press. "We are very sorry. " It was not immediately clear what led to the inaccurate reading of the water, or what the real level was. The company said on its website that there was a "mistake in the assessment of the measurement of iodine-134.

Japan's government urges residents within 18 miles of the stricken Fukushima nuclear power plant to leave their homes, as new information suggests that the core of reactor No. 3 may have been breached. Japan's government Friday urged residents within 18 miles of the stricken Fukushima nuclear power plant to leave their homes, as new information suggested that the core of reactor No. 3 may have been breached. Although people living within 12 miles of the plant were evacuated early in the crisis, those between 12 and 18 miles had been told it was safe to remain as long as they stayed indoors.

As Japan marked two weeks since the giant earthquake and tsunami, the number of people dead or missing grew to more than 27,000, with at least 200,000 others in shelters and radioactivity from a stricken nuclear plant continuing to cast a pall over daily life. Two workers at the hobbled Fukushima Daiichi nuclear facility were hospitalized for radiation exposure Thursday after stepping into contaminated water during repair operations at reactor No. 3, officials at the nation's nuclear safety agency said.

Japan's government Friday urged residents living within 18 miles of the stricken Fukushima nuclear power plant to voluntarily leave their homes and suggested that officials could expand the mandatory evacuation zone. People living within 12 miles of the plant have been evacuated, yet those living between 12 and 18 miles of the facility have been told it is safe to remain as long as they stay indoors. But two weeks after a massive earthquake and tsunami struck the country and hobbled the plant, causing radiation to leak, the situation has yet to be resolved.

Two workers at Japan's stricken nuclear facility were hospitalized Thursday after being exposed to high levels of radiation, officials at the nation's nuclear safety agency said. A third worker was also exposed but did not require hospitalization. The two hospitalized workers were exposed to 170-180 millisieverts of radiation at reactor No. 3, officials said. The average American, by comparison, is exposed 6.2 millisieverts of radiation per year from natural sources, according to the U.S. Environmental Protection Agency.

[Update 12:47 a.m.] Tokyo's utility company says black smoke has been seen emerging from Unit 3 of the crippled nuclear plant in northeastern Japan, prompting a new evacuation of the complex. Officials with Tokyo Electric Power Co. said Wednesday that workers from the entire Fukushima Dai-ichi plant have been temporarily evacuated. _________________ Control room lights were on and electronic thermometers were functioning Wednesday at several of Japan's stricken nuclear reactors, marking small but potentially critical steps toward controlling overheated fuel that has been spewing radiation for more than a week.

Reporting from Tokyo -- Infants in Tokyo and five surrounding cities should not be allowed to consume tap water, the city's government said Wednesday after elevated levels of radioactive iodine from a crippled nuclear plant were detected at a water treatment plant. Japanese Prime Minister Naoto Kan urged consumers not to eat a dozen types of contaminated vegetables from the region surrounding the nuclear facility 150 miles northeast of the capital and also expanded a shipment ban. Water tests in Tokyo found levels of radioactive iodine 131 at 210 becquerels per liter Tuesday and 190 becquerels per liter on Wednesday morning, about double the level of 100 becquerels per liter deemed safe for children under the age of 1. A level of 300 becquerels per liter is considered safe for adults.

The nuclear crisis at the Daiichi complex in Fukushima, Japan, has turned a spotlight on the severe dangers involved in storing spent nuclear fuel in pools. But the danger is not new. In 2003, I cowrote a report with a group of academics, nuclear industry executives, former government officials and other researchers warning that spent fuel pools at U.S. nuclear power plants were vulnerable. The drainage of a pool might cause a catastrophic radiation fire, we reported, which could render an area uninhabitable greater than that created by the Chernobyl accident (roughly half the size of New Jersey)