KASHIWAZAKI (Japan), July 18: The world's largest nuclear plant was ordered on Wednesday to stay shut indefinitely after Japan's deadly earthquake, as it revealed a radiation leak was worse than first thought.

The sprawling Kashiwazaki-Kariwa power plant suffered a radiation leak and dozens of other problems in Monday's 6.8-magnitude quake, whose epicentre was just nine kilometres away.Tokyo Electric Power Co. (Tepco), the operator of the plant, said the water that leaked into the sea was 1.5 times more radioactive than it initially estimated. But it said the level still did not pose a health risk.

TEPCO president Tsunehisa Katsumata said there was “no doubt that (the plant) was hit by an earthquake surpassing the limits used at the time of designing,” but that there were no serious problems with the nuclear reactors.

He earlier changed from his usual business suit to a plant worker's blue uniform to visit the site northwest of Tokyo.

“We regret what happened and will strive to make this a power plant that is safe and we can be proud of,” he said on the sidelines of the one-hour visit to the plant.

Kashiwazaki Mayor Hiroshi Aida summoned the Tepco president and banned him from reopening the plant until it is confirmed safe.

Katsumata bowed deeply before the mayor, saying: “I apologise from the bottom of my heart for causing tremendous concerns and nuisance.” Government officials and Tepco were both investigating the quake risks on Wednesday amid fears that a break in the earth crust that caused the killer quake may stretch under the seaside plant.

“We cannot deny the possibility” it sat on an earth fault, said Osamu Kamigaichi with the earthquake division of the meteorological agency.

The three municipalities housing the plant filed a joint request with Tepco, asking the company to seek approval from residents before the plant resumes operations.

The plant's operations have been suspended since the earthquake, which killed nine people, injured more than 1,000 more and sent thousands of people to shelters.

The government of Niigata prefecture was taking applications to build temporary homes for people as relief workers focused efforts on providing food and other care for the elderly, considered the most vulnerable.

But patience was tested at the shelters. Sachimi Inomata, 37, said her four-year-old daughter didn't want to use the toilets.

“She cries that it smells,” Inomata said. “I wonder why there are the same inconveniences every time a big earthquake hits Japan. They must know from past experiences what most evacuees want.” The industry ministry had already ordered the nuclear reactors of the Kashiwazaki-Kashimi facility to stay shut until its safety was confirmed.

The latest order means none of the massive plant's other important facilities such as waste storage can be used, meaning it is unlikely to be back in operation anytime soon.

The Kashiwazaki-Kariwa plant said on Monday that a small amount of radioactive water had leaked from the facility but that there was no risk.

The scare grew on Tuesday as it admitted 50 operating faults, including a fire, leakages of water and oil, misplaced duct pipes and broken equipment.—AFP