It's been a long time dream, extracting precious metals from seawater. And, it can be done IF you're willing to spend a lot of time and money on it. A news article in New Scientist reports the cost per kilogram of extracting uranium has now been cut in half, to $660.00. While that's still roughly 5 times more expensive than conventional mining methods, a turn to more nuclear power as a means to provide energy for the world without adding carbon dioxide to the atmosphere could drive up prices to the point where ocean extraction becomes viable. There's also another point to consider.
The world's oceans contain around 4.5 billion tons of uranium, enough fuel to power every nuclear plant on the planet for 6,500 years. The results were presented on 21 August at a meeting of the American Chemical Society in Philadelphia, Pennsylvannia.Discussion below the Orange Omnilepticon
Before everyone runs to invest in Oceanic Uranium shares or starts picketing the shore with No Nukes signs, let's look at some caveats.
For one, the technology is still being developed; practical exploitation could be a long time off, if ever. Oak Ridge researchers have been following up on a method pioneered by Japanese researchers.
The technology Japanese researchers pioneered uses long mats of braided plastic fibres, embedded with uranium-absorbent amidoxime, to capture trace amounts of uranium in the ocean. The mats are placed 200 metres underwater to soak up uranium before being brought to the surface. They are then washed in an acidic solution that captures the radioactive metal for future refinement.This suggests further improvements are possible - especially if nanoscale manufacturing techniques can improve on the fibers. But - it's still experimental work at this point. The BBC has more, including a surprising tie-in with developments in the Gulf of Mexico and the shrimp industry. And here's a link to a pdf file explaining the basic Japanese technology behind it all.
To make this process more economical, ORNL chemical scientist Sheng Dai says US researchers used plastic fibres with 10 times more surface area than the Japanese design, allowing for a greater degree of absorption on a similar platform.
Second, 6,500 years of supply for the existing nuclear plants is only an estimate. Increasing the number of plants, but finding ways to make them more efficient (and safer) could change that. Still, thousands of years of supply doesn't look like the worst news to come along, not with indications Peak Oil may have already occurred - and we want to move away from carbon based fuels ASAP. Wind and solar are picking up more and more of the slack, but the option of having a means of generating power in sizable quantities that isn't directly tied to the weather would give us more flexibility. (Leaving powersats out of the discussion for the moment.) Geothermal may offer some choices, but it is limited by areas where there is hot rock to tap, and possible seismic consequences from heavy exploitation.
Third, tapping the oceans for uranium avoids a lot of the problems of land-based extraction. No tearing up the landscape with excavations, no piles of slightly radioactive tailings, no contesting for leases in unstable areas of the world. Anyone with access to the oceans could potentially exploit this technology. But, refining and concentrating the uranium to usable amounts would still have problems of expense and waste, whatever the source of the uranium.
Four - This makes proliferation issues and waste management all the more critical to deal with. The United States still does not have a waste repository for current nuclear power plants. A long term investment in nuclear power can not be made without finding better answers first. Breeder reactors are one way of dealing with products of fission, by turning them into fuel. Another is using particle accelerators to transmute waste into less hazardous isotopes. Again, a lot of engineering is still needed in these areas. Proliferation issues also mean a lot more attention would need to paid to tracking who has what, where, and how secure it is if there's a shift to more nuclear power generation.
Five - the human factor. Fukushima, Chernobyl, and Three Mile Island have this in common. The most critical factor in managing nuclear power appears to be the competence of the people operating the facilities, and the willingness of the people footing the bill to pay for necessary safety measures, facilities, and the best people to run the facilities. Further, it's necessary to employ people who are both worthy of the trust invested in them AND allow them to exercise that expertise with safety as the primary criterion. The record of the for-profit nuclear industry is not encouraging, nor is the record of governments when it comes to competent oversight as opposed to CYA management or keeping well-funded lobbyists happy.
Six - The great unknown. There's room for changes in so many areas that could impact the practicality of going with more nuclear power if the oceans can become sources of fuel. There's no guaranty the process can be scaled up to useful levels. Improvements in solar power technology could change the price/performance numbers to the point that everything else becomes economically unable to compete. The Polywell experiments currently underway could turn out to be successful and practical fusion power could change everything. Or something else could turn up.
We don't have the luxury of ruling anything out at this point. Continuing to explore this technology makes sense, if only for research. (It may well prove practical for extracting other critical materials from seawater for one thing.) Anything that diverts money away from further exploitation of fossil fuels is a good thing. Nukes may not be the most attractive option with a lot of dangers - but continuing to burn oil, coal, and natural gas is already killing the planet. Wind, Solar, Geo - we need to continue with those as well. We should be hedging our bets and making a lot of them, rather than looking for the One Sure Way - because it may not exist, or we can't get there from here.
And there's one thing that's far more dangerous than nuclear power: letting Republicans have control of the government. I think we can all agree neither America or the rest of the world can survive much more of that.