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Fukushima Fallout: How Dangerous Is Japan's Creeping Nuclear Disaster?

By , Takako Maruga and

The destroyed reactors at Fukushima have been releasing radiation for weeks. According to model calculations, the stricken nuclear plant could already have released one-tenth of the amount of radiation unleashed in the Chernobyl disaster. How serious a risk does the disaster pose to humans?

Photo Gallery: Learning to Think in Millisievert Photos
DPA

The technicians had tried for days to restore electricity to the remains of the Fukushima nuclear power plant. But then it was ordinary rubber boots, of all things, that would come to symbolize their desperation, helplessness and defeat.

On Thursday, the three men had made their way into the basement of the turbine building for reactor No. 3 to examine the situation there. When they returned later, they came fully equipped with tools and protective gear that included helmets, masks, rubber gloves and raincoats on top of their radiation suits.

The one thing the men were not prepared for was that suddenly they would be wading through more than a few inches of water. Two of the workers were only wearing ankle-high boots, which allowed the water to seep in. With wet feet, the men spent three-quarters of an hour working on the cables, despite the fact that their dosimeters were beeping for a long time.

The workers are now under observation at the National Institute of Radiological Sciences. The water at Fukushima was so contaminated that radioactive beta radiation burned their skin. In less than an hour, they were exposed to about 180 millisievert of radiation, or nine times as much as one nuclear power plant employee is exposed to in an entire year. "These kinds of burns will be causing problems for the men for a long time to come," says Peter Jacob, director of the Institute for Radiation Protection at the Helmholtz Center in Munich, Germany. Commenting on the exposure, a coworker of the three men said laconically: "We do pay attention. But now we have to be even more careful as we work."

The incident revealed, once again, how little experts know about the dangers that still lurk on the grounds of the ill-fated plant. No one had expected the radiation level in the water in the basement to be as high as it was. The levels of radiation in water in the basement of reactors No. 1, No. 2 and No. 3 reached record highs, with water at No. 2 measuring 1,000 millisieverts per hour. This was due to a partial core melt. Also, the containment vessel for the third reactor was apparently damaged, representatives of the Japanese nuclear regulatory agency concluded. Could this mean that there is a crack in the barrier between the highly radioactive core and the surrounding environment?

The beginning of last week offered grounds for cautious optimism. Power had been restored to the damaged reactor No. 1, a German concrete mixer was pumping water into the dangerously empty pool containing spent fuel rods in Unit 4, and there had been no explosions in the plant for an entire week. Two weeks after the disaster in Fukushima began, all of this sounded like good news.

'An Ongoing, Massive Release of Radioactivity'

Meanwhile, however, the engineers have been forced to realize that they have made almost no headway in restoring the cooling system. By Friday night, pumps were still not working in any of the damaged reactors. Up to 45 tons of sea salt have apparently accumulated in the containment vessels, complicating the cooling effort. The salt is crystallizing in warm spots and creating an unwanted layer of insulation. The engineers planned to start flushing fresh water into the reactors on Friday afternoon. But the reactors are only one problem. There's also the issue of the 3,450 spent fuel rods, which are red-hot, presumably severely damaged and exposed to the air in half-empty pools.

"We are experiencing an ongoing, massive release of radioactivity," says Wolfram König, head of Germany's Federal Office for Radiation Protection. "And everyone should know by now that this isn't over by a long shot." Nuclear expert Helmut Hirsch says: "All I hear is that people are wondering whether this will turn into a meltdown. But the thing is, it already is a partial meltdown." The difference, in this case, is that Fukushima is a creeping disaster.

To make matters worse, the wind changed on Friday. Radioactive particles over the Pacific were now drifting westward across Japan. High levels of radiation were detected in vegetables, water and soil near the Fukushima plant.

The Japanese authorities have so far only evacuated a zone within 20 kilometers (12.4 miles) of Fukushima. But the risks posed by radiation are also growing for people outside this zone. "It is high time Japanese authorities extend the 20- kilometer (12.4-mile) evacuation zone around the crippled nuclear-power plant at Fukushima ... Pregnant women and small children should immediately be evacuated from a progressively increasing area," writes nuclear critic Mycle Schneider, lead author of the World Nuclear Industry Status Reports. Embryos, fetuses and infants are at the highest risk, because radiation targets cells that divide quickly.

There are currently 77,000 people living in emergency shelters set up in places like gymnasiums. Another 62,000 people live within the 30-kilometer zone. The head of the United States Nuclear Regulatory Agency (NRC) recommends expanding the evacuation zone to 80 kilometers, in which case 2 million people would have to be relocated -- in addition to the hundreds of thousands of earthquake and tsunami victims. Japanese authorities are now asking people to leave the area voluntarily.

The beleaguered Japanese are also being peppered with concerned advice, demands and speculation from the United States, Russia, Finland and Germany. Even France's nuclear safety agency IRSN, not exactly known for its cautionary approach to nuclear risks, published a disturbing model calculation last week. According to the report, by last Tuesday the Fukushima plant had already released into the environment one-tenth of the amount of radioactive material that was released at Chernobyl in 1986.

The International Atomic Energy Agency (IAEA), however, believes that this estimate is highly exaggerated. According to its calculations, which are based on readings taken by measuring equipment at the site, the amount of radiation released to date is only a fraction of the French estimate.

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