Workers were evacuated from Japan's damaged nuclear complex yesterday after a massive increase in radioactivity was mistakenly reported in a pool of contaminated cooling water.
The radiation level at the pool at the earthquake-stricken Fukushima plant's No 2 reactor turbine building was thought to be 1,000 millisieverts an hour, about 10 million times normal, but officials later apologised for the misreading of radiation levels that heightened fears of a meltdown and massive radiation leaks. A spokesman for Tokyo Electric Power, Takashi Kurita, said: "The number is not credible. We are very sorry."
He said officials were taking another sample to get accurate levels, but did not know when the results would be announced. The situation came as officials acknowledged radioactive water was found in the complexes that house all four of the plant's most damaged reactors.
Highly radioactive water found in the basement of the No 3 reactor last week caused two workers to be hospitalised when it burnt them after seeping through clothing.
The seawater surrounding the plant is becoming increasingly radioactive, with measurements taken on Saturday indicating radioactive iodine was 1,850 times more concentrated than the maximum safe level, up from 1,250 times the previous day. Highly radioactive water may have reached the sea through drains from the reactor facilities.
The government's nuclear agency has, however, insisted that seafood is unlikely to become contaminated, Kyodo news agency reported, because fishing vessels are not allowed within 20 kilometres of the plant as a result of the exclusion zone imposed by authorities.
Radioactivity from the plant has already contaminated farm and dairy produce from the Fukushima prefecture and neighbouring districts, causing the Japanese authorities to restrict their sale, and leading several countries including the United States, Canada, Russia and the Philippines to impose import bans.
The plant became the centre of the world's most serious nuclear incident in a quarter of a century after the March 11 earthquake and tsunami disabled systems to cool the reactors and their pools of spent fuel rods. Temperatures mounted and fuel rods partially melted, leading to increased radioactivity releases.
Engineers yesterday continued work to stabilise the plant, focusing on injecting freshwater into spent fuel pools. Due to the formation of salt crystals, the seawater used up to now will become progressively less effective. Efforts to restore power systems are also designed to allow freshwater to be mechanically pumped into the reactors themselves. Reactors No 5 and No 6 have already been stabilised and the No 4 reactor was not in use on March 11, so its fuel rods were lying in the spent fuel pool.
Although fears of a complete meltdown have receded, a Tepco official recently conceded it could take more than a month to stabilise the plant.
Yukiya Amano, the director general of the International Atomic Energy Association, told The New York Times the crisis could last for months.
"This is a very serious accident by all standards and it is not yet over," he said.
In a survey released by Kyodo yesterday, 58 per cent of Japanese did not approve of how the government has handled the crisis at the Fukushima plant, although the same percentage approved of how authorities had dealt with relief efforts for earthquake and tsunami victims. In addition, more than two thirds of those polled said they supported temporary tax increases to fund reconstruction in Japan's heavily damaged north-eastern regions. The Japanese prime minister Naoto Kan's approval rating has increased to 28.3 per cent, after falling to below 20 per cent before the crisis.
The death toll from the earthquake and tsunami stands at 10,668 and at least 16,574 people are missing.
Many survivors continue to live in evacuation centres with limited food and water supplies and medical care, although in some areas conditions have improved considerably.
Almost all the costs of rebuilding will be borne by the central government, the disaster management minister, Ryu Matsumoto, told a television programme yesterday.
The earthquake/tsunami is likely to become the most expensive natural disaster ever, and Japanese authorities having estimated that the cost of reconstruction could reach US$309 billion (Dh1.13 trillion).
* With additional reporting by Agence France-Presse