Japan: how dangerous are blasts at nuclear plants?
There has been an explosion at one nuclear facility in Japan, and now there are fears over other reactors. But how serious is the situation? Channel 4 News speaks to a nuclear expert.
The roof of a building at a nuclear plant in Fukushima, Japan, blew off in a major explosion on Saturday in the aftermath of one of the biggest earthquakes in Japanese history.
Now there are concerns over two nearby reactors at the same plant, Fukushima Daiichi, a nearby plant, Fukushima Daini, and a state of emergency has been declared at a plant in Onagawa as well. A cooling pump at a plant in Tokai has also failed, but an additional pump is working to cool the reactor.
But how serious are these explosions, and what will happen next?
Channel 4 News spoke to nuclear expert John Large, an engineer who led the risk assessment team for the raising of the damaged Russian nuclear submarine Kursk.
Twice as many people will require evacuation under a mox-fuelled reactor accident. About one and a half times as many people will die in the interim. Nuclear expert John Large
While the situation is not critical yet, he warned that the days to come could be crucial – particularly as the fuels used in one reactor at Fukushima Daiichi are more toxic, and if the fumes reach a large conurbation such as Tokyo.
Meltdown
The first explosion caused a partial meltdown in the reactor, leading the Japanese authorities to evacuate around 170,000 people and set up a 20 km exclusion zone. Some radiation is leaking, but the levels are not dangerously high, authorities said.
The explosion was a hydrogen blast, rather than nuclear fuel – but it does seem as though there has been at least a partial meltdown in this reactor.
If there is an explosion in the second reactor in Fukushima and radioactive material leaks, it could be more dangerous, Mr Large told Channel 4 News.
This is because this reactor uses “mox” fuel, or mixed oxide fuel, which contains more plutonium.
Mr Large said: “If you do an analysis of the same type of reactor, one fuelled with uranium, one fuelled with mox, what you find generally is that about twice as many people will require evacuation under a mox-fuelled reactor accident.
“About one and a half times as many people will die in the interim, and two to three more times will die in the longer term. So it has a very significant radiological impact in the aftermath of an accident.”
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He said more respiratory protection would need to be provided by the Japanese officials, or more people would have to be evacuated.
While there has not been an explosion yet, residents told Channel 4 News this was now their main fear.
One resident of Yamagata, around 150 km from the reactor in Fukushima, said: “Our main worry is the nuclear reactor in Fukushima. If it vents radiation it could blow over Yamagata, and kill farmland and harm people.”
The wind is going to switch – so it’s going to go over Tokyo. Nuclear expert John Large
Tokyo
Mr Large warned that there were two main concerns at this point, if there is an explosion at the reactor – firstly, if the wind changes.
“Round about Monday or Tuesday, the wind is going to switch and go southerly – so it’s going to go over Tokyo,” he said. “That’s the risk of a big major conurbation. The other thing is – radioactive releases don’t occur immediately once you’ve had an accident. It could be cooking, and may come out in two or three days.
“At Chernobyl for example, the significant releases were occurring on day 3, 4 and 5 after the accident.”
Last ditch attempt
For now, the authorities are pumping in seawater to cool the reactor in Fukushima, in the hope that this will be enough to avert a second explosion. It’s a last ditch attempt, which will leave the plant unable to ever produce electricity again.
Japan has lost around 20 per cent of its power as a result of the accidents, leading to black-outs across the country.
The British Ambassador to Japan, David Warren, told Channel 4 News Presenter Jon Snow that the Japanese Government was doing all they could, and he believed they were giving full information.
“The Japanese Government are trying as hard as they can,” he said. “They have given clear precautionary measures.”
But in terms of the nuclear crisis, the Japanese Government still seems to be witholding the full information from the wider world – a feature of the accident Mr Large called “disturbing” – and until they do the international community may struggle to work out exactly how dangerous the nuclear accidents may be.
