While the Japanese authorities promise to get residents of Fukushima prefecture home “as soon as possible”, the crippled nuclear plant remains a danger zone. Two specialists tell FRANCE 24 why it could still explode.
One year after the Fukushima Daiichi nuclear power plant was crippled by a massive earthquake and tsunami, the surrounding area remains highly radioactive. The looming anniversary of the catastrophe has pushed TEPCO, the plant’s disgraced operators, to admit that the situation is still hazardous. Plant director Takeshi Takahashi said last week that the company was doing “the best it could” in order to allow local residents to move back “as quickly as possible”. But he also admitted that while the station had reached “cold shutdown conditions", or a constant temperature of -100°C, it was still "rather fragile".
As Europe’s biggest nuclear producer, France has closely monitored the Japanese disaster. Two French specialists decode Takahashi’s statement.
"Reactors are still in meltdown"
Stéphane Lhomme, head of the French anti-nuclear organisation l’Observatoire nucléaire, says that TEPCO is seriously playing down potential dangers. “Their declarations are over-confident, and moreover, simply not true,” he told FRANCE 24. “The plant is neither stable nor fragile.” Lhomme describes the current situation as “catastrophic. Even if the thermal power in the four damaged reactors has been considerably reduced, they are still in meltdown and therefore still noxious.” Speaking with an alarmed tone, he says “of course the global situation is slightly better than it was a year ago. But the corium, a lava-like fuel-containing material that lies at the bottom of the containers, remains a real problem.”
Lhomme argues that at several thousand degrees, this molten lava could break through the cask at any point and destroy the concrete beneath the container, reaching soil and water located beneath the surface. “If it comes into contact with water, the corium would spark a series of massive vapour cloud explosions,” warns Lhomme.
Authorities working round the clock
Thierry Charles, security director of the French Institute of Radio-Protection and Nuclear Safety (IRSN), agrees that the remaining corium could pose a threat. “We don’t even know how much corium each cask contains,” he explains, “or how much could get through several metres of concrete.”
However, Charles is more optimistic than his colleague. “The plant is still leaking in some places and so remains fragile,” he admits. “But the situation can’t be compared with what it was a year ago. The Japanese authorities have already done plenty to tackle the problem. They have injected a cement substance into the floor of the plant, removed the debris, blocked off potential seepage points, cleaned the floors and dressed Reactor 1 in a metal cover in order to limit any fallout.”
Charles dismisses the global hysteria over radiation levels. “The main leakages happened from 12 to 25 March 2011,” he explains. “Except for caesium, most of the particles released only have a short lifespan. They lose half their strength very quickly, from within a few hours to eight days depending on the type of iodine. So except for the 30km surrounding the plan, we’re only at risk in the first few weeks after an accident.”
‘Decades before locals can move back’
Charles agrees that there is still work to do. The site must be progressively dismantled – a highly technical and expensive operation. The area surrounding the plant must also be decontaminated for local residents to be able to return home, which could take decades according to both scientists.
“It’s going to take around 30 years to completely decommission the site and ensure it’s non-hazardous,” explains Stéphane Lhomme. “After that, it will be even longer before the locals can return.” Lhomme says that the equivalent of 408 million-billion radioactive Becquerel particles lie within 30 kilometres of the plant, which itself remains a wasteland.
Even Charles agrees that the radiation levels are too high in the evacuated areas. “These places are most definitely uninhabitable,” he states.
Date created : 2012-03-06