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"However, billion-year sustainability does require advances in seawater uranium extraction..." This seems like a HUGE understatement. The calculations for the

"However, billion-year sustainability does require advances in seawater uranium extraction..." This seems like a HUGE understatement. The calculations for the billion-year sustainability basically assume we have extracted every single bit of uranium from seawater. We have demonstrated extracting uranium from seawater [0] using plastic fibers with a compound that attracts the uranium+oxygen ions. But this would basically require pumping all of the worlds oceans through these fibers and continually extracting. [0] https://engineering.stanford.edu/magazine/article/how-extract-uranium-seawater-nuclear-power#:~:text=Scientists%20have%20long%20known%20that%20uranium%20dissolved%20in,The%20uranyl%20ions%20essentially%20stick%20to%20the%20amidoxime https://engineering.stanford.edu/magazine/article/how-extrac....

Vox_Leone 5y ago
Anyway, mankind doesn't have 5Gy. In a mere 500My the sun`s output should make the planet uninhabitable. Even so, it's enough time for us to have two more pangeas.
- ben_w 5y ago
  Surprisingly, we can move the plant. At least we could if we last that long and didn’t mess up the process, neither of which I would count on. https://www.theguardian.com/environment/2001/jun/10/globalwarming.climatechange https://www.theguardian.com/environment/2001/jun/10/globalwa...
- tim333 5y ago
  Though in a century we should have people living on Mars, so a while before the 500My is up. Or a sunshade https://en.wikipedia.org/wiki/Space_sunshade https://en.wikipedia.org/wiki/Space_sunshade. Or just raise Earth's orbit a bit by slingshotting an asteroid between Earth and Jupiter. >'All you have to do is strap a chemical rocket to an asteroid or comet and fire it at just the right time,' added Laughlin. 'It is basic rocket science.' https://www.theguardian.com/environment/2001/jun/10/globalwarming.climatechange https://www.theguardian.com/environment/2001/jun/10/globalwa...
xyzzyz 5y ago
> But this would basically require pumping all of the worlds oceans through these fibers and continually extracting. Yes, and? What’s the problem here? Billion years is a plenty of time to pump all ocean water through filters. The crucial fact here is that you only need to pump through and filter as much as you need, which is much less than millions of tons of total uranium in seawater.
- kohlerm 5y ago
  Pumping the water uses energy, which changes the whole equation.
- cedilla 5y ago
  With the proposed scale of kilotons of Uranium per year, this comes still to hundreds of billions of tons of seawater every year. Now consider that only a tiny, tiny, tiny fraction of seawater is easily accessible. There's a reason why we don't do this for gold. There is about 1/50th the amount of gold in the ocean, but it's also more than a thousand times more valuable, but it's nowhere near econimcal. The scope of this product also dwarfs all proposed solutions for climate change.
  - dodobirdlord 5y ago
    > Now consider that only a tiny, tiny, tiny fraction of seawater is easily accessible. Not saying it’s an economically realistic idea, but on the topic of availability of seawater it seems like you’d just need to set up your pumping station in a location with a persistent oceanic current, filter upstream and discharge downstream, and you’d be set for thousands of years. The Straight of Gibraltar seems like a good candidate, since the large surface evaporation of the Mediterranean Sea and the comparatively small amount of water it receives from rivers means that there is a permanent current through the straight. (The Mediterranean Sea would evaporate away in about a thousand years without the Straight.) This also makes me wonder if seawater uranium concentration in the Mediterranean Sea is much higher than elsewhere. The current has been in place bringing in seawater and evaporating off the water, leaving behind all non-evaporable minerals, for over 5 million years, and the Mediterranean Sea is much saltier than the ocean in general, suggesting that uranium concentration would also be substantially elevated.

Vox_Leone 5y ago

Anyway, mankind doesn't have 5Gy. In a mere 500My the sun`s output should make the planet uninhabitable. Even so, it's enough time for us to have two more pangeas.

ben_w 5y ago
Surprisingly, we can move the plant. At least we could if we last that long and didn’t mess up the process, neither of which I would count on. https://www.theguardian.com/environment/2001/jun/10/globalwarming.climatechange https://www.theguardian.com/environment/2001/jun/10/globalwa...
tim333 5y ago
Though in a century we should have people living on Mars, so a while before the 500My is up. Or a sunshade https://en.wikipedia.org/wiki/Space_sunshade https://en.wikipedia.org/wiki/Space_sunshade. Or just raise Earth's orbit a bit by slingshotting an asteroid between Earth and Jupiter. >'All you have to do is strap a chemical rocket to an asteroid or comet and fire it at just the right time,' added Laughlin. 'It is basic rocket science.' https://www.theguardian.com/environment/2001/jun/10/globalwarming.climatechange https://www.theguardian.com/environment/2001/jun/10/globalwa...

xyzzyz 5y ago

> But this would basically require pumping all of the worlds oceans through these fibers and continually extracting. Yes, and? What’s the problem here? Billion years is a plenty of time to pump all ocean water through filters. The crucial fact here is that you only need to pump through and filter as much as you need, which is much less than millions of tons of total uranium in seawater.

kohlerm 5y ago
Pumping the water uses energy, which changes the whole equation.
cedilla 5y ago
With the proposed scale of kilotons of Uranium per year, this comes still to hundreds of billions of tons of seawater every year. Now consider that only a tiny, tiny, tiny fraction of seawater is easily accessible. There's a reason why we don't do this for gold. There is about 1/50th the amount of gold in the ocean, but it's also more than a thousand times more valuable, but it's nowhere near econimcal. The scope of this product also dwarfs all proposed solutions for climate change.
- dodobirdlord 5y ago
  > Now consider that only a tiny, tiny, tiny fraction of seawater is easily accessible. Not saying it’s an economically realistic idea, but on the topic of availability of seawater it seems like you’d just need to set up your pumping station in a location with a persistent oceanic current, filter upstream and discharge downstream, and you’d be set for thousands of years. The Straight of Gibraltar seems like a good candidate, since the large surface evaporation of the Mediterranean Sea and the comparatively small amount of water it receives from rivers means that there is a permanent current through the straight. (The Mediterranean Sea would evaporate away in about a thousand years without the Straight.) This also makes me wonder if seawater uranium concentration in the Mediterranean Sea is much higher than elsewhere. The current has been in place bringing in seawater and evaporating off the water, leaving behind all non-evaporable minerals, for over 5 million years, and the Mediterranean Sea is much saltier than the ocean in general, suggesting that uranium concentration would also be substantially elevated.