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  • - There's an urban legend that when grave-robbers

  • found their way to ancient Egyptian tombs,

  • there were warnings they ignored.

  • "Do not open this tomb.

  • "Do not steal the riches inside.

  • "You will be cursed and you will die."

  • It's not true. Not just the curses aren't real,

  • but those warnings were just an urban legend.

  • The robbers wouldn't have been able to read them.

  • And even if they could, the messages weren't warning of curses.

  • They were just the ancient equivalent of a 'no trespassing' sign.

  • This is Olkiluoto, an island on the far west of Finland.

  • And here, they're building a tomb for something that really is dangerous.

  • In a few years, the deep bedrock here

  • will contain the world's first long-term storage site

  • for high-level nuclear waste,

  • right next to some of the reactors that produce it.

  • This isn't a video about whether nuclear power is good or bad.

  • I think it's good, and so, it seems, does Finland.

  • The third reactor here is being tested now and it's due to go online next year.

  • But this video is about a different question.

  • We do have nuclear power in the world,

  • so where do we put the waste?

  • I didn't know how it would feel until I stood here.

  • It is very strange to have 400 metres of rock above my head

  • and knowing that inside that solid plug of clay there

  • there is high-level radioactive waste.

  • This new tunnel complex is called Onkalo, which translates as 'cavity'.

  • And long-term storage really does mean long-term:

  • 100,000 years.

  • To put that in perspective,

  • 100,000 years ago, humans hadn't made it to Europe yet;

  • the continent was still frozen in the middle of an ice age.

  • Our species were just hunter-gatherers.

  • This facility is being designed to last for geological time.

  • And yes, despite the fact

  • that there are hundreds of nuclear reactors in the world,

  • right now there is no permanent geologic storage facility anywhere

  • for high-level radioactive waste, the spent nuclear fuel, the really nasty stuff

  • that could cause disasters if it leaks.

  • Now, the problem isn't urgent.

  • The world doesn't actually produce that much of it, relatively speaking.

  • A century's worth of high-level waste from all the current reactors in Finland

  • will fit in the final version of this one new facility.

  • But right now, around the world, high-level radioactive waste

  • is generally stored near reactors,

  • first in water ponds that require active cooling,

  • and then in concrete casks that'll last,

  • well, about as long as a concrete building would;

  • not long enough.

  • The US has been trying to work out a storage site for years,

  • but their one serious attempt, Yucca Mountain,

  • has been mired in politics for decades.

  • Finland, here, is closest to building that solution.

  • - The geology in Finland is very old.

  • We are talking about two thousand million years

  • is the age of what we have below our feet here.

  • And in that way, it's really stable

  • and it represents the most ancient parts of this Earth.

  • High-level waste will be disposed of with cast-iron copper canisters,

  • and the canisters are put into the hole in the deposition tunnels

  • and then these are surrounded by bentonite clay.

  • Clay has a low hydraulic conductivity,

  • which means that the water doesn't transport through the clay.

  • The spent fuel, when it's taken from the reactors into the disposal,

  • it's highly radioactive.

  • But with time, the radioactivity will decrease.

  • After 500 years, people can stand beside the canister

  • and it's not dangerous.

  • But there are some other long-lived radionuclides

  • which might be harmful

  • in case they were to come up to the surface

  • and into the drinking water, into the wells or biosphere,

  • and therefore the geological disposal

  • will isolate the waste for 100,000 years.

  • - This area isn't prone to earthquakes or other natural disasters.

  • Geologically, it's about as peaceful as you can get.

  • So, the plan is: dig the tunnels

  • and then, for 100 years, put the casks of waste in,

  • and then backfill each tunnel with clay so they're encased in solid rock.

  • And once the site is full, fill in every bit of it,

  • every last tunnel, and then leave it forever.

  • There are multiple levels of containment.

  • The idea is that even if one or two of them fail,

  • everything will still be safe for 100,000 years,

  • unless someone digs it up.

  • When the US government was thinking about using Yucca Mountain as its storage site,

  • they commissioned a now-famous report on how to mark a site like this.

  • How do you warn people away,

  • even if our civilization has collapsed,

  • our language has fallen apart,

  • and no one knows what radiation is?

  • There were all sorts of ideas, from a spike field to 'forbidding blocks'.

  • But all those would ultimately be a big sign saying,

  • "Hey, there's something interesting under here; dig!"

  • - The facilities will be closed in about 100 years,

  • 6,500 tonnes of uranium.

  • We have not decided what is the best way to mark that.

  • - There was one other idea in that research paper:

  • Don't mark the site at all.

  • One the repository is full,

  • fill it in, seal it shut, and then hide it

  • so there's nothing remarkable at the surface.

  • There are very few reasons to dig this deep, particularly here.

  • The odds are slim that some future archaeologist

  • would deside to dig 400 metres down in this remote location.

  • And if they did, if someone ignored all the warnings

  • or arrived after everything had been eroded away up top,

  • well, if they did break through all the containment

  • in search of treasure,

  • what they'd get is radiation poisoning and a particularly unpleasant death.

  • If the grave-robbers that dug up Egyptian tombs

  • had started rapidly and obviously dying from a real curse,

  • maybe they would've taken the hint.

  • Thank you so much to all the team at Olkiluoto

  • who showed me and all the camera teams who are down here today around.

  • You can find out more about them in the links in the video description.

  • All right, thank you. Your turn!

- There's an urban legend that when grave-robbers

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10万年分の核廃棄物を貯蔵するトンネルの内部 (Inside The Tunnels That Will Store Nuclear Waste For 100,000 Years)

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    林宜悉 に公開 2021 年 01 月 14 日
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