Yoshihiko Noda says the most critical phase is over at Fukushima Daiichi, but it is not clear when residents can return
Japan's prime minister, Yoshihiko Noda, has declared an end to the most critical phase of the accident at Fukushima Daiichi nuclear power plant, but conceded that the crisis is far from over.
In a nationally televised address on Friday, Noda said the plant had been brought to a state of "cold shutdown", a significant step towards resolving the crisis, nine months after it was struck by a powerful earthquake and tsunami that left almost 20,000 people dead and missing along the country's north-east coast.
Cold shutdown is achieved when the temperature of water used to cool nuclear fuel rods remains below boiling point and radiation emitted by the reactors is no higher than the government-set limit for the public of one millisieverts a year.
In April, the plant's operator, Tokyo Electric Power (Tepco), said it aimed to stabilise the reactors by the end of the year, but it managed to bring water temperatures to below boiling point for the first time in September. Officials say that the temperatures inside reactors number one to three, which all suffered meltdown, now range from 38C to 68C.
Noda apologised for the anxiety the nuclear accident – the world's worst since Chernobyl 25 years ago – had caused before paying tribute to the thousands of workers, soldiers and firefighters who had risked their health battling to bring the plant under control.
He said radiation levels at the plant's boundary could be kept at low levels, even in the case of an "unforeseen incident".
But he was unable to offer a date for the return of any of the 80,000 residents evacuated from a 12-mile radius of the plant in the immediate aftermath of the accident, when three of six reactors suffered core meltdown.
"Our ultimate aim remains to get people back to their homes and resume the lives they had before the accident as quickly as possible," he said.
The government, he added, would do its best to decommission the plant now that it has been stabilised. "The government is due to set a clear road map and will do the utmost to decommission the plant," he told reporters.
Decommissioning will be a time-consuming and expensive process; estimates put the cost at between 1.15 trillion yen (£9.5bn) and 4 trillion yen.
The government has conceded that workers will not be able to start removing the molten fuel from the three worst-hit reactors for another 10 years. They plan to remove spent fuel from four storage pools within the next two years, reports said.
Tepco must also find a way to treat and dispose of an estimated 90,000 tonnes of contaminated seawater that has been used to cool the reactors. The operation to cool nuclear fuel rods and prevent further radiation leaks into the sea and atmosphere has suffered several setbacks. Earlier this month, for example, Tepco said about 45 tonnes of highly radioactive water had leaked through a crack in the wall of a treatment facility.
On Thursday, government officials said it could take as long as 40 years to decommission the plant and decontaminate an area of about 930 square miles (2400 sq km).
Experts have warned that another strong earthquake or tsunami could damage the plant's makeshift cooling system and set off a second crisis.
The government is expected to review the evacuation of at least some of the residents forced to abandon their homes in the hours after the tsunami on 11 March. Those living closest to the plant have been told their former neighbourhoods could remain uninhabitable for decades.
The crisis has taken a huge financial toll on Tepco, which has been criticised for its haphazard initial response to the accident and its handling of compensation claims.
Reports said the government was preparing to inject $13bn into the firm, a de facto nationalisation designed to keep it afloat as it compensates victims and begins the clean-up operation.
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Source: http://www.guardian.co.uk/world/2011/dec/16/fukushima-cold-shutdown-japanese-pm1
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