Tokyo: Efforts have been stepped up to cool reactors at the Fukushima Daiichi nuclear plant. Military helicopters dumped tonnes of water to try to prevent a meltdown of fuel rods. Water cannon will join the operation shortly and it is hoped electricity will be restored soon.
Increasing alarm has been expressed in the US at the crisis.
Police say 5,178 are confirmed dead and another 8,606 people are still missing.
CH-47 Chinook helicopters began spraying tonnes of water on reactors three and four at Fukushima, 220km from Tokyo, at 0948 local time, officials said.
The aircraft dumped four loads before leaving the site in order to minimise the crews’ exposure to radiation. On Wednesday, the helicopters were forced to abort a similar operation amid concerns over high radiation levels.
Media reports say the helicopters can carry an enormous amount of water but given the high winds it is difficult to know whether it has been dropped accurately.
Japanese government spokesman Yukio Edano said at a news briefing that nuclear experts were now investigating how effective the operation was.
Meanwhile, water trucks are on standby to spray more water on the reactors.
The operation was intended to help cool the reactors and also to replenish water in a storage pond with spent fuel rods.
Officials also said they were hoping that later on Thursday they would restore the power supply to the plant, which is needed for the cooling system and backup generators.
“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,” a spokesman for Tokyo Electric Power Company, which runs the plant, said.