Australian news, and some related international items

University boffins discuss the eternal problem of nuclear wastes

Amazing – still none of these scientists suggests stopping making this radioactive trash!
The problem of nuclear waste, The Naked Scientists, 07 April 2020    Interview with Claire Corkhill, University of Sheffield

Part of the show The Rise of Radioactivity

  Our issues with radioactivity though are obviously not behind us. A major headache today is how to handle and safely store nuclear waste. Here in the UK, we’ve got 650,000 cubic metres of the stuff – enough to fill Wembley Stadium – and it’ll be radioactive and dangerous for 100,000 years. ……..
Chris – So what do we do with all this stuff? We end up with these barrels of what looks like glass or concrete; that sounds fine. What do we do, just bury them?
Claire – Well, they’re currently packaged in specially-engineered containers and stored in over 20 different secure nuclear sites around the country, and most of it is at Sellafield in Cumbria. And these stores are designed to withstand extreme weather and earthquakes. But the problem that we have is that the waste is so radioactive, we can’t actually go anywhere near it. If you were to touch the outside of one of the glass waste containers, the radiation dose that you’d receive is 200,000 times more than a fatal dose of radiation. So whilst it’s okay to store the waste securely for the time being, it’s clear that we need a more permanent solution that requires less security. So remember, these wastes will be radioactive for over a hundred thousand years and they’ll be highly radioactive for several thousands of years, so we can’t just leave them in their warehouses and hope that future civilizations will know what to do with them.
 ……………………These nuclear waste materials will change over the hundred thousand years that they’ll be radioactive. And there are some different ways that this might occur. One would be corrosion, so the natural corrosion of the materials once they’re buried deep under the ground, which is their final disposal route; if they slowly corrode in groundwater they may release their radioactivity. But the other issue is, as you rightly noted, that the radioactivity inside the waste might actually cause the waste itself to break down. And you can think of this as a highly energetic particle, a bit like was described before with breaking DNA; instead of breaking DNA we’re actually breaking the intrinsic chemical bonds inside our nuclear waste material, and this will essentially cause the waste to disintegrate. And this is something that we have to understand.

Chris – So what you’re saying is, if we’ve got say something that looks like glass, because it’s spitting out all these energetic particles of radiation all the time, it’s slowly going to shatter the glass. It’s almost like shaking the glass very, very hard for hundreds of thousands of years; it’s eventually going to fall to pieces and it will no longer be any good at retaining and constraining the radioactive products inside.

Claire – Essentially yes…….

Adam – How do we design something in the future so that this stuff stays where it is, and isn’t archeologist bait, and they suddenly dig up a radioactive cube of glass?

Claire – At the present time we are thinking that we will not mark when nuclear waste is kept. It’s going to be buried deep below the ground and nobody will know it’s there. The worry about putting a marker on the surface is that it will automatically draw, humans particularly because we’re very inquisitive, to that site to find out what’s going on. …… the plan at the moment is to not mark the waste and hope that people forget about it; and that if in the future they decide to dig there, they have the technology to dig that deep – so we’re talking between 500 metres and a kilometre below the ground – and if they have that technology, then they will also have some technology to be able to detect the radiation and know that they shouldn’t go there.

April 9, 2020 - Posted by | General News

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