Australia won't be exposed to a substantial increase in radioactivity as Japan's nuclear crisis unfolds, but the situation at Fukushima's crippled power plants is getting worse, according to Professor Jim Falk, from the Melbourne School of Land and Environment.
In an interview with SBS, he says the world is entering unexplored territory with the Fukushima nuclear disaster:
What is radiation sickness?
Radiation sickness is caused by the cells in the body breaking down under the impact of ionising radiation, and it causes blemishes in the skin, and it causes breakdowns in the gut, and in extreme cases it causes catastrophic breakdown in vital organs and you die.
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How many people around the world since nuclear energy became an issue, have been affected by radiation sickness?
That's very difficult to say. Any increase in radiation increases the probability that you'll get cancer. And that's not radiation sickness but that is a much more pervasive effect than acute radiation sickness. When you look at the nuclear fuel cycle you have to look at how much radiation is released in its many different forms and how many people that over their lifetime would have shortened their lifetimes.
What are the risks? Are they different if the radiation is airborne, or in the water, or in the soil?
Different risks associate with different ways of getting the radiation to your body. If you're exposed to so-called gamma radiation, like x-rays, then that produces [broad] impacts of radiation across your body.
If you take in a radioactive particle, whether it be of smoke, or if it be dissolved into water, for example plutonium, caesium, or iodine-131, then the body can concentrate it into particular organs. For example iodine-131 gets concentrated into the thyroid, and there you can get an internal dose of radiation to that organ. Then you can have different sorts of radiation, whilst plutonium on your skin's not going to give you a problem, because it's a so-called alpha emitter, if it's absorbed into the lungs a very small amount of it can give you an increased chance of getting lung cancer.
On a scale what would be the most dangerous way to be in contact with radioactive contaminants and what would be the least dangerous?
The most dangerous is to get a dose of more than four and a half sievert, [at] which dose about half the population exposed will die in the not too distant future from acute radiation exposure.
Where to now for the people around Fukushima?
What we're seeing now, it's rather like a slow motion collision, taking part over weeks. In a way we're being reassured all the time it's not going to get worse. But it is getting apparently worse. Initially people were told to stay indoors and they were told to evacuate out to 30 kilometres, the US said evacuate out to 80 kilometres. Then they said we should evacuate the next 10 kilometres out and people who can are no doubt doing so.
But the problem is that the problem is getting worse, and we're seeing now highly radioactive water in large quantities accumulating at the reactor site, especially around, it seems like a leak from unit 2, which may well be a very substantial core meltdown, with the so-called corium, the liquid fuel burning its way through the metal of the primary vessel and possibly accumulating then on the concrete chamber beneath it and we don't know where it's going or what it's going to do after that.
So we don't know for sure that that's the situation, but now there are some indications from the sort of isotopic mix that we're getting that that's the case. So we have a worsening situation, and it'd be a good thing to be a considerable way away from the reactor site.
Is the Japanese government being sufficiently cautious?
It is quite common with all major nuclear reactor accidents, the authorities tend not to want to frighten people, they tend to try and calm people, they tend to avoid what could happen, and they tend to be reluctant to evacuate unless they really feel they absolutely have to, and they often leave it too late, and they often give too insufficient information. And all of those things have been characteristic of this particular chain of events.
What number of people would be affected if there was a meltdown at Fukushima?
Nobody knows because it depends exactly on the conditions, and it depends on exactly what the meltdown does. This is unexplored territory. The molten fuel can interact with the concrete, if there's water down there … it can form steam explosions, we might see more hydrogen explosions if there's still zirconium cladding involved.
There could be fires, we've had fires already at Fukushima, if indeed any of those happen to amplify the amount of radioactive material getting into the atmosphere, then it depends on where the wind is blowing, it depends on the sorts of nuclides that are in the plume, where it blows, who's there, and then of course the human activities that interact with that, so, food becoming contaminated, transported.
One way or another, there are so many possible ways in which this could play out it's impossible to predict at this point.
Do Australians have anything to worry about at all?
We may see some trace increases in radioactivity. I doubt we'll see anything very substantial. Any increase in radiation increases our risk of getting cancer. There is no such thing as a safe dose of radiation. But the risk increase can be trivial in comparison to other risks we accept. And I suspect in Australia we're not going to see direct effects of that sort.
We may see contaminated food here arrive if things aren't monitored properly. I know the Chinese have already turned away a vessel which was showing a higher than normal level of radiation. We may see more of that, it may be amplified. But I think our main concern should be the people in Japan.
