SENDAI, Japan – Japanese engineers were Thursday focusing their efforts on restoring the power supply to a quake-damaged nuclear plant in an attempt to reactivate its cooling system and avert a meltdown.
Last Friday's massive earthquake and tsunami knocked out the power supply and back-up generators at the Fukushima No. 1 plant on the Pacific coast, some 250 kilometres (155 miles) northeast of Tokyo.
The lack of power has sent temperatures soaring in reactors with fuel rods being exposed as the cooling water evaporated and emitting hydrogen gas and possibly radioactive material, triggering fears of a meltdown.
Plant operator Tokyo Electric Power Co. (TEPCO) said it was preparing to restore outside power lines and connect its damaged transmission system to unaffected lines.
"At the moment, we are concentrating our efforts on this work," spokesman Naohiro Omura told AFP.
"If the restoration work is completed, we will be able to activate various electric pumps and pour water into reactors and pools for spent nuclear fuel."
The Japanese crews grappling with the world's worst nuclear incident since Chernobyl in 1986 were briefly evacuated Wednesday after a spike in radiation levels at the plant.
Earlier they contended with a new fire and feared damage to the vessel containing one of the plant's six reactor cores.
There are also major fears about pools holding spent fuel rods at the plant, which need water to keep them cool. Unlike the reactors, they have no containment vessels.
Some 70 workers have been using low-capacity fire pumps to pour seawater to cool reactors at the plant, according to media reports. They are using electricity from borrowed power supply cars.
A Japanese army helicopter Wednesday aborted its mission to dump water onto the fuel rods due to the high level of radiation above the reactors.
UN atomic watchdog chief Yukiya Amano said the situation at the plant was "very serious" as he prepared to fly out to see the damage for himself.
Japan's Emperor Akihito gave a rare address to a jittery nation Wednesday as the nuclear emergency deepened and millions struggled in desperate conditions after the quake and tsunami disaster.
The television appearance by the emperor emphasised the gravity of the crisis gripping Japan after the 9.0-magnitude quake and the monster waves it unleashed.
Akihito said he was "deeply concerned" about the "unpredictable" situation at the stricken power plant.
"I sincerely hope that we can keep the situation from getting worse," Akihito said in a historic televised address that marked the first time he has intervened in a national crisis.
Gregory Jaczko, chair of the US Nuclear Regulatory Commission, warned there was no water left in the spent fuel pool of reactor 4, resulting in "extremely high" radiation levels.
The US military will send a spy drone to take a closer look at the reactors in the troubled plant, Kyodo News reported.
Engineers have been desperately battling a feared meltdown at the 40-year-old plant since the earthquake and tsunami knocked out cooling systems and fuel rods began overheating.
The workers at the plant, which has been hit by four explosions and two fires, have been hailed as heroes.
"Please don't forget that there are people who are working to protect everyone's lives in exchange for their own lives," said one post on Japanese social networking site Mixi.
The government has warned people living up to 10 kilometres (six miles) beyond the 20-kilometre exclusion zone around the plant to stay indoors. More than 200,000 people have already been evacuated from the zone.
The US embassy in Tokyo warned American citizens living within 50 miles (80 kilometres) of the plant to evacuate or seek shelter.
Other foreign governments also urged their citizens to steer clear of the quake-stricken northeast of Japan and the capital Tokyo amid fears of further aftershocks and a widening nuclear disaster.
Japan's chief government spokesman Yukio Edano however said radiation levels from the plant posed no immediate health threat outside the 20-kilometre exclusion zone.
But as crews battled to prevent a nuclear meltdown, the European Union's energy chief said the situation had spun out of control.
"The site is effectively out of control," energy commissioner Guenther Oettinger told a European Parliament committee, one day after he said Japan was facing "apocalypse."
France's Nuclear Safety Authority said the disaster now equated to a six on the seven-point international scale for nuclear accidents, ranking the crisis second only in gravity to the level-seven Chernobyl disaster in 1986.
Amano, the Japanese chief of the International Atomic Energy Agency, had insisted Tuesday there was no comparison to the Chernobyl crisis, when radiation spewed across Europe.
Aside from the nuclear threat, the full scale of the quake and tsunami disaster was becoming clear as more details emerged of the staggering death and devastation in the worst-hit northeast.
"The number of people killed is increasing day by day and we do not know how many people have fallen victim," said the emperor, who is held in deep respect by many Japanese. "I pray for the safety of as many people as possible."
"People are being forced to evacuate in such severe conditions of bitter cold, with shortages of water and fuel... I cannot help praying that rescue work is done swiftly and people's lives get better, even a little."
And already jangled nerves were frayed further by a series of aftershocks including a strong 6.0-magnitude earthquake that swayed buildings in Tokyo.
The official toll of the dead and missing after the quake and tsunami flattened Japan's northeast coast rose to nearly 13,000, police said, with the number of confirmed dead at 4,314.
But reports continued to come in which indicated that the final toll could be much higher, with the mayor of the coastal town of Ishinomaki saying the number of missing there was likely to hit 10,000, Kyodo News reported.
On Saturday, public broadcaster NHK reported that around 10,000 people were also unaccounted for in the port town of Minamisanriku, again in Miyagi prefecture.
Millions have been left without water, electricity, fuel or enough food and hundreds of thousands more are homeless, stoically coping with freezing cold and wet conditions in the northeast.
The governor of Fukushima prefecture, home to the crippled nuclear plant, said people were at breaking point.
"The worry and anger of the people of Fukushima has been pushed to the limit," Yuhei Sato told NHK.
With nerves on edge across the world's third-biggest economy and beyond, people across Asia have been stripping shelves of essentials for fear of a major emission of radiation from the power plant on the east coast.
The Japanese government has warned that panic buying in towns and cities that have not been directly affected by the twin disasters could hurt its ability to provide aid to the devastated areas.
Radiation levels in the capital's vast urban sprawl of 30 million people have see-sawed without ever reaching harmful levels, according to the government.
Beyond Japan, Asian nations vowed to crack down on hoax messages warning about radiation spreading beyond Japan, which have helped stoke growing unease over the unfolding crisis.