Re: Nuclear waste, I've often wondered...

[Binkie The Clown]

There are subduction zones on the ocean floor where ocean crust is pushed down and continental crust rides up over the top of it.



Anything at the bottom of a subduction trench gets pulled deep into the molten mantle where it is melted and isolated from the surface for at least millions of years, and at most, essentially forever.

What would be wrong with sealing atomic waste against leakage and dropping it into subduction trenches? It's not just temporary storage, but permanent removal from the surface of the planet.

[GliderGuider]

1. That's been my favourite disposal idea for a long time.

I'm not sure why no-one is pursuing it. I am sure that someone here can tell us, though.

[NV Whino]

2. My guess is too much $$$$$.

And/or no one profits from it.

[FBaggins]

3. That's clever

In the end, I suspect that the incredibly slow pace of subduction (combined with the fact that the zones are almost always under the sea) probably rules it out.

[OKIsItJustMe]

4. Why Not Dispose of Waste in Ocean Trenches?

http://geology.about.com/od/platetectonics/f/seadisposal.htm

[font face=Serif][font size=3]…

Even the fastest subduction is very slow, geologically slow. The fastest-subducting location in the world today is the Chile Trench, running down the west side of South America. There the Nazca plate is plunging beneath the South America plate at about 25 centimeters (10 American inches) a year. It goes down at about a 30-degree angle. So if we put a barrel of nuclear waste in the Chile Trench (never mind that it's in Chilean national waters), in a hundred years it will move 25 meters—as far away as your next-door neighbor. Is that anyone's idea of efficient?

After their hazardous period of 10,000 years those waste barrels would have moved just 2.5 kilometers, about a mile and a half, and would lie only a few hundred meters deep. (Remember that every other subduction zone is slower than this.) And for all that time they could be easily dug up by whatever future civilization cares to retrieve them. After all, have we left the Pyramids alone? Even if future generations left the waste alone, the seawater and seafloor life would not, and the odds are good that the barrels would corrode and be breached.

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[Binkie The Clown]

5. Good points. Thanks for those answers. n/t

[OKIsItJustMe]

6. You’re welcome!

Personally, I’ve been a fan of glass, since the 1984 World’s Fair (the Australian pavilion had a simulated cylinder of “vitrified” waste.)

https://www.shef.ac.uk/news/nr/nuclear-waste-storage-glass-sheffield-1.203561

[font face=Serif]22 August 2012

[font size=5]Glass offers improved means of storing UK’s nuclear waste[/font]

[font size=4]University of Sheffield researchers have shown, for the first time, that a method of storing nuclear waste normally used only for High Level Waste (HLW), could provide a safer, more efficient, and potentially cheaper, solution for the storage and ultimate disposal of Intermediate Level Waste (ILW).[/font]

[font size=3]Currently the UK’s preferred method is to encapsulate ILW in specially formulated cement. The waste is mixed with cement and sealed in steel drums, in preparation for disposal deep underground.

Two studies, published in the latest issues of The Journal of Nuclear Materials and European Journal of Glass Science and Technology A show that turning this kind of waste into glass, a process called vitrification, could be a better method for its long-term storage, transport and eventual disposal.

…

A key discovery made by the Sheffield team was that the glasses produced for ILW proved to be very resistant to damage by energetic gamma rays, produced from the decay of radioactive materials.

…[/font][/font]

Now though, I’m more interested in something like Transatomic’s proposed reactor. (Let’s not just hide it under the rug somewhere and hope that it doesn’t cause problems in the future…)

[FBaggins]

7. You've hit on a big part of the best solution

Regardless of industry, the best thing to do with "waste" is to find a use for it. Then it's no longer waste, it's a resource.