Washington: President Barack Obama, trying to reassure a worried nation, declared on Thursday that "harmful levels" of radiation from the Japanese nuclear disaster are not expected to reach the US, even as other officials conceded it could take weeks to bring the crippled nuclear complex under control.
The situation remains dangerous and complicated at the damaged Fukushima Daiichi reactors in northeastern Japan, US officials said.
"We`ve seen an earthquake and tsunami render an unimaginable toll of death and destruction on one of our closest friends and allies in the world," Obama said in brief remarks at the White House after a visit to the Japanese embassy to offer his condolences.
Obama said he had asked the Nuclear Regulatory Commission to conduct a "comprehensive review" of the safety of all US nuclear plants.
"When we see a crisis like the one in Japan, we have a responsibility to learn from this event and to draw from those lessons to ensure the safety and security of our people," Obama said.
There are 104 nuclear reactors in the United States, providing roughly 20 percent of the nation`s electricity. "Nuclear energy is an important part of our own energy future," Obama said.
A leading industry group agreed with the review.
"A review of our nuclear plants is an appropriate step after an event of this scale and we expect that the Nuclear Regulatory Commission will conduct its own assessment," said Marvin Fertel, president of the Nuclear Energy Institute.
"The industry`s highest priority is the safe operation of 104 reactors in 31 states and we will incorporate lessons learned from this accident..."
Meanwhile, the first evacuation flight of US citizens left Japan, the State Department said.
In the US, Customs and Border Protection said there had been reports of radiation being detected from some cargo arriving from Japan at several airports, including ones in Chicago, Dallas and Seattle.
Radiation had not been detected in passengers or luggage. And none of the reported incidents involved harmful amounts.
Homeland Security Secretary Janet Napolitano said the agency was screening passengers and cargo for "even a blip of radiation”.
Obama said he knows that Americans are worried about potential risks from airborne radiation that could drift across the Pacific. "So I want to be very clear," he said. "We do not expect harmful levels of radiation to reach the United States, whether it`s the West Coast, Hawaii, Alaska or US territories."
Obama defended the recommendation of federal nuclear safety officials for a 50-mile evacuation zone around the crippled nuclear power plant for American troops and citizens in Japan, even though that is far larger than the zone spelled out by Japanese officials.
"This decision was based on a careful scientific evaluation," Obama said. "Beyond this 50-mile radius, the risks do not currently call for an evacuation."
At the same time, he said it was important to evacuate Americans "who may be endangered by exposure to radiation if the situation deteriorates”.
Japanese officials have established a 12-mile evacuation zone and have said that people living 12 to 20 miles from the plant should stay inside.
Gregory Jaczko, chairman of the Nuclear Regulatory Commission, told reporters at a White House briefing it could be some time before the crisis is brought under control as crews work to cool spent-fuel rods and get the damaged Japanese reactors under control. The activity could continue for days and "possibly weeks”, Jaczko said.
He said the US recommendation that American troops and citizens stay 50 miles away from the nuclear complex was "a prudent and precautionary measure to take”. But he also said "basic physics" suggested there was little risk to anyone in the United States or its Pacific territories.
Daniel B Poneman, deputy secretary of energy, told the briefing that a "very dangerous situation" remains in Japan. Information at the nuclear plant is "genuinely complex and genuinely confusing”, he said.
As the officials spoke, Japanese emergency workers sought to regain control of the dangerously overheated nuclear complex, dousing it with water from police cannons, fire trucks and helicopters to cool nuclear fuel rods that were threatening to spray out more radiation.
The US Energy Department said it had conducted two separate aerial tests to measure how much radioactive material had been deposited in Japan. Those data, Poneman said, were consistent with the recommendation for Americans to evacuate a 50-mile radius around the plant.
The US officials declined to criticise the Japanese call for a smaller evacuation zone.
At his visit to the Japanese embassy, Obama signed a condolence book and said: "We feel a great urgency to provide assistance to those ... who are suffering."
In the book he wrote, "My heart goes out to the people of Japan during this enormous tragedy. Please know that America will always stand by one of its greatest allies during this time of need."
"Because of the strength and wisdom of its people, we know that Japan will recover, and indeed will emerge stronger than ever," he wrote.