A global nuclear disaster potentially worse than Chernobyl may be under way in Japan as hundreds of tonnes of highly radioactive spent nuclear fuel are open to the sky, and may be on fire and emitting radioactive particles into the atmosphere.
Many countries have advised their citizens in Japan to leave the country.
“This is uncharted territory. There is a 50-percent chance they could lose all six reactors and their storage pools,” said Jan Beyea, a nuclear physicist with a New Jersey consulting firm called Consulting in the Public Interest.
“I’m surprised the situation hasn’t gotten worse faster… But without a breakthrough it’s only a matter of days before spent fuels will melt down,” said Ed Lyman, a physicist at the Union of Concerned Scientists and an expert on nuclear plant design.
Japan’s Fukushima Daiichi plant was damaged by a powerful earthquake and tsunami on Mar. 11. It has an estimated 1,700 tonnes of used or spent but still dangerous nuclear fuel in storage pools next to its six nuclear reactors, according to Kevin Kamps, a radioactive waste specialist at Beyond Nuclear, a U.S. anti-nuclear environmental group.
The storage pools holding 30 to 35 years worth of spent fuel at reactors No. 3 and No. 4 have lost containment and most if not all of their coolant water. They may be on fire, venting radioactive particles into the atmosphere, Kamps told IPS.
On Thursday, Japanese military helicopters protected by lead shielding managed to dump some seawater on the damaged reactors No. 3 and No. 4 in a desperate and very risky last- ditch effort at the highly radioactive site.
“If some of the spent fuel ignites and propagates throughout the rest of the fuel enormous areas of Japan could be contaminated by radioactive caesium 137 for 30 to 50 years,” Beyea told IPS.
Caesium 137 remains radioactive for more than a hundred years and is a known cause of cancer and other health impacts. Once released, it is very difficult to cope with. Caesium is why a large region around the 1986 Chernobyl nuclear disaster remains uninhabitable 25 years later.
A 2010 health study by the University of South Carolina in the U.S. showed that children born after the disaster and living more than 75 kilometres away have long-term problems with their lungs resulting from caesium 137 in dust and soil particles.
“Caesium particles were blown hundreds of miles away during the intense fire at Chernobyl,” Kamp said.
For comparison, Chernobyl held 180 tonnes of nuclear fuel. Fukushima Daiichi has 560 tonnes of nuclear fuel in its reactors along with 1,700 tonnes of spent fuel.
“The nuclear industry in Japan and the U.S. knew the loss of coolant at spent-fuel storage pools would be a big problem but they simply said it couldn’t happen,” said Beyea, who is a co-author of a 2004 study on this very topic for the U.S. National Research Council of the National Academy of Sciences.
Having worked in the industry, Beyea says it is run by overconfident engineers who minimise or ignore low- probability disasters even if they might have huge consequences.
Nuclear reactors generate enormous amounts of heat and must be constantly cooled to keep the metal fuel casing from catching on fire and the fuel from melting. Since a nuclear reaction cannot be turned off, when spent fuel is removed from a reactor it still generates a great deal of heat and must be cooled underwater for five to 20 years. All reactors have storage pools with thick reinforced-concrete walls and are about 15 metres deep, containing around 1.5 million litres of water. This water soon warms and must be constantly replaced with cooler water.
The loss of electricity and failures of backup generators at Fukushima Daiichi has meant little water has been pumped through the storage pools or into the reactors. Radiation levels inside the plant have now climbed so high that it is hazardous for workers to try to keep jury-rigged pumps pumping sea water. Normally only fresh water is used because sea water contains salts that eventually degrade the metals.
Radiation levels are deadly when there is not enough water to cover a spent fuel pool, said Kamps. “It will be very difficult to get close enough to cool these pools down,” he noted. “If the worst happens, and the six pools burn, it will be an unimaginable disaster. It could be worse than Chernobyl.”
The amount of caesium that could be released at Fuskushima is many thousands times that from the Hiroshima atomic bomb during World War Two, acknowledged Beyea. However, it was the bomb blast that killed over 120,000 people in the immediate months afterwards, he said.
“Japan is facing enormous potential impacts on its economy, its society and on the health of its people,” he said, adding that people will be worried sick about the potential impacts on their health for decades to come.
“We recommended that the nuclear industry move spent fuel into dry storage containers after five years to reduce this risk but they said a loss-of-pool coolant event would never happen,” said Beyea.
The status as of Thursday, 4 pm EST according to Tokyo Electric, the owner and operator of Fukushima Daiichi nuclear plant:
Reactors No. 1, No. 2 and No. 3 nuclear cores have partially melted as they lost cooling functions after the quake.
Reactor No. 2 containment vessel suffered damage and has been breached.
The buildings housing the No. 1, No. 3 and No. 4 reactors and storage pools have been severely damaged by apparent hydrogen blasts.
Water levels and temperatures at storage pools of the Nos. 1 to 4 units are unknown.
Temperatures at storage pools at No. 5 and No. 6 are climbing.
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