Wednesday, April 13, 2011

Another Chernobyl?

The Japanese authorities declared yesterday that Fukushima was a 'Level 7' accident, on the same level as Chernobyl, on the international nuclear incident scale.

I am aware of international paranoia about Fukushima, but I am nevertheless surprised at this.

In the Chernobyl accident, an entire reactor melted down, spewing radioactive material high into the atmosphere where it spread to vast areas around it.  About 30 people died directly from radiation.  The number of long-term deaths caused by Chernobyl depends on what you read, but estimations range from zero to several tens of thousands  Even Wikipedia, which I consider in general the best source of information on the plant, seems unsure, suggesting anywhere from 500 to several thousand.  One issue is that thryoid cancer, the main cancer caused by Chernobyl, has very low incidence rates and a high survivability.  Not only that, but health conditions in the region around the plant are generally not very good in any case, so it's hard to differentiate Chernobyl-induced disease from the usual alcoholism and other health afflictions of the region.  But certainly mainstream experts suggest many people were adversely affected.

In Fukushima nobody at all has died from radiation.  Two people were reported to have been exposed to dangerous levels but it seems like they never got sick.  As for radiation releases, the total amount of radiation released is less than 10% of that released by Chernobyl, and much more localised.  So I am baffled by the decision to place Fukushima in the same band as Chernobyl.  '7' is supposed to be the highest on the scale: what are they going to do in a genuine catastrophe?

It was also announced that a few areas outside the current 30 km exclusion zone will be evacuated, as occupants staying for an entire year will absorb about '20 millisieverts' of radiation, which is substantially greater than background radiation.  Well, okay, you might think.  Sounds dangerous.  But some google searching reveals that 20 millisieverts is well...not very much at all.  More than background, sure.  But the maximum permissable amount of radiation absorbed over the course of a year is set at 50 millisieverts for American nuclear power plant workers.  And the absolute minimum amount that is said to be linked to cancer is 100 millisieverts.  In any words, the amount of radiation accumulated by residents who lived for a year in these areas would be one-fifth of that required to be linked to any cancer.  In addition, as work progresses at the plant, steadily but slowly, radiation levels will decrease so that residents would be absorbing less and less.


The emperor visits an evacuation centre styled by new fashion designer '100 yen'

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