NUCLEAR FEARS:JAPAN IS struggling to contain a growing crisis at two nuclear power plants damaged in Friday's huge earthquake and tsunami, as officials revealed that the emergency cooling system at a third reactor had failed, raising fears of a serious accident.
Officials said the negligible radioactivity levels near the plants in Fukushima prefecture posed no threat to human health. Screening centres were being set up for people worried about exposure.
Tokyo Electric Power [Tepco] described the situation at the Fukushima No 1 power plant as an emergency after the cooling system failed at a second reactor at the plant.
Tepco said radiation levels at the plant had exceeded the legal limit yesterday morning. Hourly radiation at the site was measured at 882 microsievert, in excess of the allowable level of 500, Japan’s nuclear safety agency said. The government’s chief spokesman, Yukio Edano, said the level had briefly risen to 1,204 microsievert.
“There was no sudden rise in radiation because of the ventilation activities,” Mr Edano said, adding that there was no immediate threat to human health.
“We are doing the two things at the same time – venting air out of the reactor and supplying water into the reactor.”
As authorities released steam to relieve pressure from the second overheating reactor, efforts were under way to evacuate 210,000 people living within 12 miles of the two plants.
Among those waiting to leave was Reiko Takagi, who lives in Iwaki, about 18 miles from the No 1 plant.
“Everyone wants to get out of the town, but the roads are terrible,” she said. “It is too dangerous to go anywhere, but we are afraid that winds may change and bring radiation toward us.”
Mr Edano said: “There is no confusion at this point, although we appreciate that people will have to leave their homes and livelihoods behind, but there is no panic.”
Efforts were also under way to cool off three reactors at the firm’s No 2 nuclear plant at Fukushima, about 150 miles north of Tokyo.
The complete failure of more cooling systems has added an additional level of danger to what was already one of the worst nuclear accidents in Japan’s history. The government has classed the accident as level 4 on an international scale of levels 0-7.
At least 22 people are known to have been exposed to radiation and are being treated in hospital, but Japan’s nuclear and industrial safety agency said that up to 160 people may have been exposed.
Tepco confirmed that the No 3 reactor of the quake-hit No 1 Fukushima plant had lost its cooling functions.
A small amount of radiation leaked on Saturday after similar problems hit the facility’s No 1 reactor. Nineteen people were exposed to radioactivity yesterday; three more were exposed when the roof over the No 1 reactor exploded on Saturday.
Tepco said the No 1 reactor had partly melted – the first time this has happened in Japan – and was continuing efforts to cool the reactor with seawater, a procedure a British nuclear expert described as “an act of desperation”.
The company notified the government yesterday morning that the No 3 reactor had lost the ability to cool the reactor core and that radioactive steam was being released. Kyodo News quoted Tepco as saying that up to three metres (10ft) of fuel rods were exposed above water at the plant.
Shaun Burnie, an independent nuclear energy consultant and former head of nuclear campaigns at Greenpeace, said the presence of a percentage of fuel core loaded with plutonium mox (mixed oxide) fuel in the No 3 reactor posed a grave threat to the surrounding area.
“Plutonium mox fuel increases the risk of nuclear accident due to the neutronic effects of plutonium on the reactor,” Mr Burnie said.
“In the event of an accident – in particular loss of coolant – the reactor core is more difficult to control due to both neutronics and higher risk of fuel cladding failure.
“In the event of the fuel melting and the release of plutonium fuel into the environment, the health hazards are greater, including higher levels of latent cancer.”
The mox fuel was delivered in 1999 and was loaded into the reactor by Tepco only last year after sitting in Fukushima storage ponds amid opposition and delays from the prefecture’s governor, Mr Burnie added.
The No 3 reactor is the sixth facing risks because of loss of cooling water since Friday’s devastating quake and tsunami.
Tepco last night filled the No 1 reactor with seawater and boric acid to prevent criticality – an uncontrolled nuclear reaction – hours after an explosion blew away the roof and walls of a building housing the reactor. – (Guardian service)