The U.N. nuclear agency says the situation at Japan’s earthquake and tsunami-crippled nuclear reactor is “very serious” but there has been “no significant worsening” in the past 24 hours.
IAEA official Graham Andrew said at a press conference in Vienna on Thursday that radiation doses had risen “significantly” in some locations as far as 30 kilometers from the Fukushima plant, but that in the capital Tokyo they were well below levels considered dangerous to human health.
But he added it was possible the situation “could get worse.”
The Japanese military on Thursday used high-pressure fire hoses in a desperate attempt to douse nuclear fuel rods that began overheating after the plant’s cooling systems failed. If the rods become hot enough, they can melt or burn through their outer casing, releasing high levels of radiation into the air.
Earlier Thursday, the government used aerial water drops — after aborting the plan a day earlier because of radiation danger to the helicopter pilots.
Defense Minister Toshimi Kitazawa said the government had decided it “could not delay the mission any further.” But televised pictures showed much of the water being blown away from the target and the effort was suspended after four attempts.
High radiation levels around the plant 240 kilometers north of Tokyo are making it impossible for workers to stay at the facility for more than a few minutes at a time, and initial radiation readings suggest the first helicopter drops had little effect.
Greg Jaczko, head of the U.S. Nuclear Regulatory Commission, said Thursday it would be a “prudent measure” for its citizens to follow US government advice to stay at least 80 kilometers from the plant — a radius much larger than the Japanese exclusion zone. He described the situation at the Fukushima plant as “very dynamic.”
Many governments are evacuating staff from embassies in Tokyo. The United States on Thursday authorized the evacuations of family members and dependents of U.S. personnel and said chartered flights would be provided to help U.S. who want to leave Japan.
U.S. President Barack Obama telephoned Prime Minister Naoto Kan early Thursday in Tokyo to express his admiration for the courage of the Japanese people and renew his offer of assistance, including with the nuclear crisis.
The prime minister’s office Thursday called on citizens to save electricity as it warned of a “massive power outage” in the area served by the Tokyo Electric Power Company, TEPCO.
Normal cooling systems for the plant were destroyed by last week’s earthquake and tsunami, which knocked out electricity to the plant and damaged emergency backup generators.
Japanese officials said Thursday they soon hope to restore electricity to the 40-year-old plant, raising hopes that more efficient pumps can be deployed to apply water to the fuel rods at the crippled plant’s six nuclear reactors. But chief government spokesman Yukio Edano warned that even then, much of the original pumping equipment has been damaged by seawater and will have to be replaced.
Three of the plant’s six reactors were operating when the quake struck, while three others were shut down for maintenance. All three of the reactors that were operating have since suffered explosions that destroyed their outer housing. Officials believe that at two of the units, the explosions also ruptured the inner containment chambers which protect against radiation leaks.
But current concerns are focused on cooling tanks at all six reactors where used fuel rods are stored. For months, these remain hot enough to catch fire and release lethal radiation unless they can be kept under sufficient amounts of water.
Japan has evacuated more than 200,000 people from a 20-kilometer radius around the plant and advised anyone within 30 kilometers to remain indoors. Many are huddled in makeshift facilities amid frigid temperatures and scarce food supplies.
In his phone call to Mr. Kan, Mr. Obama said the United States “is determined to do everything possible to support Japan in overcoming the effects” of last week’s earthquake and tsunami.
He expressed his extraordinary admiration for the character and resolve of the Japanese people” and discussed U.S. assistance including “military assets with expertise in nuclear response and consequence management.”