Lately, I’ve been spending some time reading through reports on nuclear waste management. What is striking is how conservative the calculations seem to be; for example, the report by Posiva (the Finnish company responsible for the world’s first civilian nuclear waste repository, Onkalo) goes to almost absurd lengths when calculating what might be a possible highest dose for the single worst-affected individual ten thousand years from now.

For example, the calculations assume that the person in effect spends all of his or her days – from birth to death – in the single worst contaminated one square meter plot around the repository; eats nothing but the most contaminated food available, with a diet that maximizes radionuclide intake; and drinks only the most contaminated water and nothing else. The figure – 0.00018 milli-sieverts per year – also assumes that the copper canisters where spent fuel pellets are housed begin to leak after mere 1000 years.

And still, the worst-case figures amount to a dose what one would get from eating about two bananas.

I’m fully prepared to accept that many surprising things could happen, and that we cannot be certain of what happens 10 000 years from now; but given the figures here, and the way they’re achieved, I have some confidence that the likelihood of people receiving doses that can actually pose some real danger, even in the long term (say, more than 10 mSv per year – which might just produce enough cancer cases to be visible in statistical sense) seems remote indeed.

You can read the Posiva Biosphere Assessment report (be warned, it’s 192 pages of rather technical text) in English here:

Click to access POSIVA_2010-03web.pdf

As always, corrections and comments are highly appreciated. You’re also free to distribute the image as you see fit – just provide a link to this page.