There’s much screaming and shouting from the usual suspects about the new radiation leak discovered at Fukushima, the stricken nuclear power plants in Japan. What they’re not telling you is that the radiation leakage is around the same as 76 million bananas. A fact which should help to put it all into some perspective. Here’s Greenpeace:
Environmental group Greenpeace said Tepco had “anxiously hid the leaks” and urged Japan to seek international expertise.
“Greenpeace calls for the Japanese authorities to do all in their power to solve this situation, and that includes increased transparancy…and getting international expertise in to help find solutions,” Dr Rianne Teule of Greenpeace International said in an e-mailed statement.
Not that Greenpeace is ever going to say anything other than that nuclear power is the work of the very devil of course. And the headlines do indeed seem alarming:
Radioactive Fukushima groundwater rises above barrier – Up to 40 trillion becquerels released into Pacific ocean so far – Storage for radioactive water running out.
Or:
Tepco admitted on Friday that a cumulative 20 trillion to 40 trillion becquerels of radioactive tritium may have leaked into the sea since the disaster.
Most of us haven’t a clue what that means of course. We don’t instinctively understand what a becquerel is in the same way that we do pound, pint or gallons, and certainly trillions of anything sounds hideous. But don’t forget that trillions of picogrammes of dihydrogen monoxide is also the major ingredient in a glass of beer. So what we really want to know is whether 20 trillion becquerels of radiation is actually an important number. To which the answer is no, it isn’t. This is actually around and about (perhaps a little over) the amount of radiation the plant was allowed to dump into the environment before the disaster. Now there are indeed those who insist that any amount of radiation kills us all stone dead while we sleep in our beds but I’m afraid that this is incorrect. We’re all exposed to radiation all the time and we all seem to survive long enough to be killed by something else so radiation isn’t as dangerous as all that.
At which point we can offer a comparison. Something to try and give us a sense of perspective about whether 20 trillion nasties of radiation is something to get all concerned about or not. That comparison being that the radiation leakage from Fukushima appears to be about the same as that from 76 million bananas. Which is a lot of bananas I agree, but again we can put that into some sort of perspective.
Let’s start from the beginning with the banana equivalent dose, the BED. Bananas contain potassium, some portion of potassium is always radioactive, thus bananas contain some radioactivity. This gets into the human body as we digest the lovely fruit (OK, bananas are an herb but still…):
Since a typical banana contains about half a gram of potassium, it will have an activity of roughly 15 Bq.
Excellent, we now have a unit that we can grasp, one that the human mind can use to give a sense of proportion to these claims about radioactivity. We know that bananas are good for us on balance, thus this amount of radioactivity isn’t all that much of a burden on us.
We also have that claim of 20 trillion becquerels of radiation having been dumped into the Pacific Ocean in the past couple of years. 20 trillion divided by two years by 365 days by 24 hours gives us an hourly rate of 1,141,552,511 becquerels per hour. Divide that by our 15 Bq per banana and we can see that the radiation spillage from Fukushima is running at 76 million bananas per hour.
Which is, as I say above, a lot of bananas. But it’s not actually that many bananas. World production of them is some 145 million tonnes a year. There’s a thousand kilos in a tonne, say a banana is 100 grammes (sounds about right, four bananas to the pound, ten to the kilo) or 1.45 trillion bananas a year eaten around the world. Divide again by 365 and 24 to get the hourly consumption rate and we get 165 million bananas consumed per hour.
We can do this slightly differently and say that the 1.45 trillion bananas consumed each year have those 15 Bq giving us around 22 trillion Bq each year. The Fukushima leak is 20 trillion Bq over two years: thus our two calculations agree. The current leak is just under half that exposure that we all get from the global consumption of bananas.
Except even that’s overstating it. For the banana consumption does indeed get into our bodies: the Fukushima leak is getting into the Pacific Ocean where it’s obviously far less dangerous. And don’t forget that all that radiation in the bananas ends up in the oceans as well, given that we do in fact urinate it out and no, it’s not something that the sewage treatment plants particularly keep out of the rivers.
There are some who are viewing this radiation leak very differently:
Arnold Gundersen, Fairewinds Associates: [...] we are contaminating the Pacific Ocean which is extraordinarily serious.
Evgeny Sukhoi: Is there anything that can be done with that, I mean with the ocean?
Gundersen: Frankly, I don’t believe so. I think we will continue to release radioactive material into the ocean for 20 or 30 years at least. They have to pump the water out of the areas surrounding the nuclear reactor. But frankly, this water is the most radioactive water I’ve ever experienced.
I have to admit that I simply don’t agree. I’m not actually arguing that radiation is good for us but I really don’t think that half the radiation of the world’s banana crop being diluted into the Pacific Ocean is all that much to worry about.
And why we really shouldn’t worry about it all that much. The radiation that fossil fuel plants spew into the environment each year is around 0.1 EBq. That’s ExaBecquerel, or 10 to the power of 18. Fukushima is pumping out 10 trillion becquerels a year at present. Or 10 TBq, or 10 of 10 to the power of 12. Or, if you prefer, one ten thousandth of the amount that the world’s coal plants are doing. Or even, given that there are only about 2,500 coal plants in the world, Fukushima is, in this disaster, pumping out around one quarter of the radiation that a coal plant does in normal operation.
You can worry about it if you want but it’s not something that’s likely to have any real measurable effect on anyone or anything.
ORIGINAL: Forbes
By Tim Worstall, Contributor
8/10/2013
