Soaring radiation in sea near nuke plant
Engineers battle to pump out water at stricken reactor
Published 27/03/2011 | 05:00
Japanese engineers struggled last night to pump radioactive water from a crippled nuclear power station after radiation levels soared in seawater near the plant more than two weeks after it was battered by a huge earthquake and a tsunami.
Tests on Friday showed iodine-131 levels in seawater 30km from the coastal nuclear complex had spiked 1,250 times higher than normal, but it was not considered a threat to marine life or food safety, the Nuclear and Industrial Safety Agency said.
"Ocean currents will disperse radiation particles and so it will be very diluted by the time it gets consumed by fish and seaweed," said Hidehiko Nishiyama, a senior agency official.
Despite that reassurance, the disclosure is likely to heighten international concern over Japanese seafood exports. Several countries have already banned milk and produce from areas around the Fukushima Daiichi plant, while others have been monitoring Japanese seafood.
Prolonged efforts to prevent a catastrophic meltdown at the 40-year-old plant have also intensified concern around he world about nuclear power.
UN Secretary-General Ban Ki-moon said it was time to reassess the international atomic safety regime.
The crisis at the plant, 240km north of Tokyo, has overshadowed a big relief and recovery effort from the magnitude 9.0 quake and the huge tsunami it triggered on March 11 that left more than 27,100 people dead or missing in northeast Japan.
Engineers trying to stabilise the plant have to pump out radioactive water after it was found in buildings housing three of the six reactors.
On Thursday, three workers were taken to hospital from reactor No 3 after stepping in water with radiation levels 10,000 times higher than usually found in a reactor. That raised fear the core's container could be damaged.
An official from plant operator Tokyo Electric Power Co (Tepco) told a news conference that experts still had to determine where to put some of the contaminated water while engineers were still trying to fully restore the plant's power.
Tepco said it was using fresh water instead of seawater to cool down at least some of the reactors after concern arose that salt deposits might hamper the cooling process.
Two of the plant's reactors are now seen as safe but the other four are volatile, occasionally emitting steam and smoke. But the nuclear safety agency said yesterday that temperature and pressure in all reactors had stabilised.
The government has said the situation was nowhere near to being resolved, although it was not deteriorating.
"We are preventing the situation from worsening -- we've restored power and pumped in fresh water -- and making basic steps towards improvement but there is still no room for complacency," chief cabinet secretary Yukio Edano told a news conference yesterday.
More than 700 engineers have been toiling in shifts but there's no end in sight.
At Three Mile Island, the worst nuclear power accident in the United States, workers took just four days to stabilise the reactor, which suffered a partial meltdown. No one was injured and there was no radiation release above the legal limit.
At Chernobyl in Ukraine, the worst nuclear accident in the world, it took weeks to "stabilise" what remained of the plant and months to clean up radioactive materials and cover the site with a concrete and steel sarcophagus.
So far, no significant levels of radiation have been detected beyond the vicinity of the plant in Fukushima.
In Tokyo, a Reuters reading yesterday morning showed ambient radiation of 0.22 microsieverts per hour, about six times normal for the city.
That was well within the global average of naturally occurring background radiation of 0.17-0.39 microsieverts per hour, a range given by the World Nuclear Association.
The government has prodded tens of thousands of people living in a 20km-30kmzone beyond the stricken complex to leave. Edano said the residents should move because it was difficult to get supplies to the area, and not because of elevated radiation.