A glimmer of hope emerged from the deepening crisis at the Fukushima Dai-ichi nuclear power plant in Japan, as the International Atomic Energy Agency announced Thursday that engineers began laying an external power line to one of the crippled reactors.
Plant operators have been racing to finish a new power line that could restore the cooling systems and ease the crisis at the plant, on the country's northeast coast. The IAEA initially reported Thursday that the cable had been laid to the reactor, but later clarified its statement and said work had begun.
These efforts appeared to be bearing some fruit late Thursday, but officials with the Tokyo Electric Power Co., or TEPCO, also acknowledged that the pumps that circulate water inside the reactors and require electricity to work properly could be corroded with seawater. This would mean TEPCO would have to replace the pumps to keep the cores, which house the heated fuel rods, cooled.
This came after a day of little apparent progress bringing the crisis at the Fukushima Dai-ichi nuclear complex under control. Helicopters, water cannons and fire trucks all struggled to deliver water to cool overheating nuclear fuel rods at the stricken complex.
Japanese military helicopters made the first attempt. Using tactics similar to those used for fighting wildfires, they tried to dump loads of seawater onto a pool that contains used uranium fuel that is overheating and highly radioactive at the plant's reactor No. 3.
The fuel inside the pool is supposed to be covered with water, which keeps it cool and prevents the radiation from leaking out. But Friday's earthquake and subsequent tsunami disrupted part of the plant's cooling system at all six units.
Two CH-47 Chinook helicopters began dumping seawater on the complex's damaged reactor No. 3 at 9:48 a.m. local time (8:48 p.m. EDT Wednesday), Defense Ministry spokeswoman Kazumi Toyama said. The choppers dumped at least four loads on the reactor in just the first 10 minutes, though television footage showed much of it appearing to disperse in the wind.
Trucks with water cannons that are normally used to control rioting crowds then started spraying the same pool. But Japan's national broadcaster, NHK, reported that one try proved the strategy is futile: Radiation levels were simply too high, and the truck couldn't get close.
At 7:35 p.m. local time (6:35 a.m EDT) Thursday, five Self-Defense Forces emergency fire vehicles shot 30 tons of water aimed at the spent fuel pool for about 30 minutes. It is not known whether the water reached its target, but officials said 30 tons of water wasn't even enough to fill the pool to a safe level.
"They said they sprayed about 30 metric tons of water, which is better than nothing, but clearly they are not refilling the pools with that amount of water," NPR's Richard Harris told All Things Considered host Michele Norris.
Officials say they plan to resume both the helicopter and the water truck operation Friday morning.
"This clearly is a stopgap though because they have to devise a better system to get water in those pools ... and reduce the risk of an explosion there," Harris said. "And they really need to restore electricity to the power plant so they can start using the pumps that are built into the power station."
U.S. Concerns
Meanwhile, U.S. officials speaking at the White House about the nuclear crisis in Japan said the plant's troubles pose no risk to the United States at this time. But Daniel B. Poneman, deputy secretary of energy, said the situation in Japan remains "very dangerous."
Obama administration officials also expressed frustration with the sporadic and often conflicting information trickling from Japanese government sources.
"It's not easy to get information from the site," said White House spokesman Jay Carney.
Poneman added that the data they were getting from the site were "genuinely complex and genuinely confusing."
The state of the pools of used nuclear fuel at reactors No. 3 and No. 4 has emerged as the most urgent problem at the nuclear complex. The reactors themselves are sealed off in steel vessels inside huge concrete containment vessels. So even though some of the fuel inside has melted, most of the radiation is contained. The spent fuel pools, on the other hand, are inside ordinary buildings that are more vulnerable because of explosions and fires.
"We are afraid that the water level at unit No. 4 is the lowest," said Hikaru Kuroda, facilities management official at TEPCO. But, he added, "because we cannot get near it, the only way to monitor the situation is visually from far away."
The U.S. military has sent an unmanned aerial drone to fly above the complex and take pictures.
'Like Suicide Fighters In A War'
Emergency workers were forced to temporarily retreat from the plant Wednesday when radiation levels soared, losing precious time. While the levels later dropped, they were still too high to let workers get close.
A core team of 180 emergency workers has been at the forefront of the struggle at the plant, rotating in and out of the complex to try to reduce their radiation exposure.
But experts said anyone working close to the reactors was almost certainly being exposed to radiation levels that could at least give them much higher cancer risks. The International Atomic Energy Agency says 21 people at the plant have sustained injuries since the tsunami and two have "suddenly taken ill."
"I don't know any other way to say it, but this is like suicide fighters in a war," said Keiichi Nakagawa, associate professor of the Department of Radiology at University of Tokyo Hospital.
Experts note, though, that radiation levels drop quickly with distance from the complex. While elevated radiation has been detected well outside the evacuation zone, experts say those levels are not dangerous.
Stopgap Measures
The Japanese government said it had no plans to expand its mandatory, 12-mile exclusion zone around the plant, while also urging people within roughly 20 miles to stay inside.
The top U.S. nuclear regulatory official gave a far bleaker assessment of the situation and the U.S. ambassador said on Wednesday that the situation was "deteriorating" while warning U.S. citizens within 50 miles of the complex to leave the area or at least remain indoors. Officials reaffirmed the decision Thursday, calling it "a prudent move."
The troubles at the nuclear complex began when last week's magnitude 9.0 earthquake and tsunami knocked out power and destroyed backup generators needed for the reactors' cooling systems.
Four of the plant's six reactors have faced serious crises involving fires, explosions, damage to the structures housing reactor cores, partial meltdowns or rising temperatures in the pools used to store spent nuclear fuel. Officials also announced that temperatures are rising in the spent fuel pools of the last two reactors, though they say at the current rate it will be another week before temperatures in those reactor pools reach critical levels.
Ultimately, the only solution is to restore power to the plant so that cooling systems can begin working again. Everything else is a stopgap measure.
NPR's Christopher Joyce and Richard Harris contributed to this report, which contains material from The Associated Press
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