JAPAN’S nuclear crisis escalated dramatically yesterday as two further explosions and a fire at the earthquake-crippled Fukushima Daiichi power plant sent dangerous levels of radiation into the atmosphere.
Much lower but abnormal radiation and traces of radioactive elements were detected around Greater Tokyo, the world’s most populous metropolitan region with 36 million people.
Thousands of Tokyo residents were last night leaving the capital for cities further south, fearing northerly winds would sweep radioactive smoke and steam from the Fukushima plant towards the capital 250km away.
However, the UN’s weather agency said late last night that the winds had shifted and were now blowing the radioactive material towards the Pacific Ocean.
As the fallout from the explosion in the No 2 reactor spread, there were unconfirmed reports last night of overheating problems at Fukushima Daiichi’s No 5 and No 6 reactors. A government spokesman said there had been “slight temperature rises” in the units that had not previously given any noticeable trouble.
Those reactors, like the No 4 reactor where yesterday’s fire occurred, were idled for safety and maintenance when the plant was swept by a powerful tsunami wave generated by Friday’s magnitude-9 earthquake.
The tsunami, rather than the earthquake, appears to have been the trigger for the succession of critical failures that followed.
Prime Minister Naoto Kan warned at a nationally televised press conference yesterday that “radiation levels around the compound have risen to fairly high levels”.
“There is a danger of even higher radiation levels,” he said. “We are making every effort to prevent the leak from spreading. I know that people are very worried but I would like to ask you to act calmly.”
Mr Kan warned people living within a 20km to 30km radius of Fukushima Daiichi to stay indoors, after radiation equivalent to 400 times the safe level of human exposure in a year was detected at the plant yesterday morning.
About 160,000 residents have already been evacuated from inside the 20km exclusion zone and the Transport Ministry yesterday imposed a 30km no-fly zone for all aircraft, excluding those engaged in earthquake relief activities.
Four countries in Asia – Hong Kong, The Philippines, Singapore and South Korea – began testing Japanese food imports for radiation yesterday.
The death toll from Friday’s earthquake off the northeast coast of Japan and subsequent tsunami is expected to pass 10,000, with emergency crews only now arriving at some of the worst-hit areas.
The official death toll yesterday rose to 2414, but that does not yet include the thousands of bodies police found washed up on beaches in the Miyagi prefecture.
Aid workers and search teams from across the world joined 100,000 Japanese soldiers in a massive relief push in the shattered areas, where the tsunami swallowed entire towns.
Up to half a million people remain homeless as the emergency centres across the quake-stricken region struggle to accommodate those displaced by the disaster.
Millions of others are still without water, electricity or enough food, heightening the sense of panic across the region.
For the first time since Friday, the government conceded an immediate and significant threat to human health.
“Now we are talking about levels that can damage human health,” said Chief Cabinet Secretary Yukio Edano. “These are readings taken near the area where we believe the [radiation] releases are happening.”
Mr Edano said radiation near the No 3 reactor reached 400 millisieverts hourly yesterday morning. He insisted the radiation levels in areas of Greater Tokyo, including Saitama, Kanagawa, Ichihara in Chiba and at least one site in the central city, Shinjuku, were not hazardous. “The radioactive substances will likely spread far and wide in minute amounts, but these doses will not be enough to cause any harm,” he said.
Several Tokyo embassies suggested non-essential staff and citizens should consider leaving and the French embassy forecast that wind-borne low-level radiation could reach the capital by 10pm yesterday. International commentators were divided in their analysis of the scale of the danger, with French Foreign Minister Alain Juppe saying the threat was “extremely high” while others said it was too early to compare it with the 1986 Chernobyl disaster.
Yesterday, the plant operator, Tokyo Electric Power Co, acknowledged for the first time that the most dangerously unstable of the four reactors now affected, the No 2 unit, was at risk of a serious meltdown. Radioactive steam continued to be vented yesterday from three reactors to reduce internal pressures.
A fire that overheated spent fuel rods stored in a “suppression pond” at the No 4 reactor appeared to have been responsible for the largest direct release of radioactive particles yesterday.
The International Atomic Energy Authority, which was officially asked by Japan yesterday morning for help with the crisis, said it had been informed from Tokyo that the No 4 fire was extinguished in the early afternoon. “Japanese authorities today informed the IAEA that the spent fuel storage pond at the Unit 4 reactor of the Fukushima Daiichi nuclear power plant is on fire and radioactivity is being released directly into the atmosphere,” the IAEA said in a statement.
That incident brought the number of reactors involved in the crisis to four out of six and quickly followed an alarming build-up of events during the previous 18 hours at the No 2 reactor, which is the focus of most anxiety.
An explosion soon after 6am local time was feared to have damaged the reactor’s pressure-suppression system, the Nuclear and Industrial Safety Agency said.
Radiation levels at the plant rose quickly again after the reported explosion and the agency said it was concerned radioactive material might be leaking.
Mr Edano said the reactor’s containment vessel might have been damaged, raising the risk of uncontrolled radiation release.
A defect had been detected in the vessel and the No 2 reactor “was not necessarily in a stable condition”.
Fuel rods in the No 2 reactor became exposed for a second time early yesterday. TEPCO began trying to pump seawater back into the damaged reactor core about 3am yesterday but pressure build-up within was making pumping difficult. At one stage late last night, radiation levels at the plant reached six times the allowable power station level.