Japan expanded the evacuation zone around a crippled nuclear plant today because of high levels of accumulated radiation, as a strong aftershock rattled the area one month after a quake and tsunami sparked the worst nuclear crisis since Chernobyl.
The operator of the crisis-hit Fukushima Daiichi nuclear complex said it had stopped releasing low-level radioactive water into the sea, completing the controlled discharges that sparked concerns about contamination in neighbouring China and South Korea.
Tokyo Electric Power Co (Tepco) said 10,400 tonnes of low-level radioactive water, left by the tsunami, had been pumped back into the sea to free up storage capacity for highly contaminated water from the reactors.
Japan may raise the Fukushima nuclear accident to level seven on its severity scale, matching that of Chernobyl, Kyodo reported tonight.
A magnitude 6.6 tremor shook buildings in Tokyo and a wide swathe of eastern Japan today, killing one man, knocking out power to 220,000 households and causing a brief halt to water pumping to cool three damaged nuclear reactors.
The epicentre of quake, which was followed by more than 25 aftershocks today, was 88km east of the Fukushima Daiichi nuclear complex at the centre of the crisis.
The biggest tremor forced engineers to postpone plans to remove highly contaminated water from one reactor, but nuclear safety officials said work had resumed by nightfall.
The government announced earlier that because of accumulated radiation contamination, it would encourage people to leave certain areas beyond its 20km exclusion zone around the plant.
Children, pregnant women, and hospitalised patients should stay out of some areas 20-30 km from the nuclear complex, Chief Cabinet Secretary Yukio Edano told reporters.
"These new evacuation plans are meant to ensure safety against risks of living there for half a year or one year," he said. There was no need to evacuate immediately, he added.
Engineers at the plant north of Tokyo said they were no closer to restoring the plant's cooling system, which is critical to bring down the temperature of overheated fuel rods and to bringing the six reactors under control.
In a desperate move to cool the highly radioactive fuel rods, Tepco has pumped water onto reactors, some of which have experienced partial meltdown.
But the strategy has hindered moves to restore the plant's internal cooling system as engineers have had to focus on how to store 60,000 tonnes of contaminated water.
The triple earthquake, tsunami, and nuclear disaster is the worst to hit Japan since the second World War, leaving nearly 28,000 dead or missing and rocking the world's third-largest economy.
Concern at the government's struggle to handle the situation is mounting, with Prime Minister Naoto Kan's ruling party suffering embarrassing losses in local elections yesterday.
Voters vented their anger at the government's handling of the nuclear and humanitarian crisis, with Mr Kan's ruling Democratic Party of Japan losing nearly 70 seats in local election.
The unpopular Mr Kan was already under pressure to step down before March 11th, but analysts say he is unlikely to be forced out during the crisis, set to drag on for months.
Reuters