Energy

Cost-effective method of extracting uranium from seawater promises limitless nuclear power

This first gram of yellowcake was produced from uranium captured from seawater with modified yarn
This first gram of yellowcake was produced from uranium captured from seawater with modified yarn
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This first gram of yellowcake was produced from uranium captured from seawater with modified yarn
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This first gram of yellowcake was produced from uranium captured from seawater with modified yarn
Test set up for uranium extraction
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Test set up for uranium extraction
Material designed to capture uranium from seawater as an alternative to land-based mining of the fuel for nuclear power production is tested at PNNL's Marine Sciences Laboratory
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Material designed to capture uranium from seawater as an alternative to land-based mining of the fuel for nuclear power production is tested at PNNL's Marine Sciences Laboratory

The Pacific Northwest National Laboratory (PNNL) in association with LCW Supercritical Technologies has made an important breakthrough for the nuclear industry by extracting 5 grams of powdered uranium, called yellowcake, from ordinary seawater. The new process uses inexpensive, reusable acrylic fibers and could one day make nuclear energy effectively unlimited.

Along with salt, a liter of seawater also contains sulfates, magnesium, potassium, bromide, fluoride, gold, and uranium. There isn't much of the latter – something like 3 micrograms per liter (0.00000045 ounces per gallon), but when you consider how big the ocean is, that works out to 500 times more uranium in the sea than could be mined on land – that's 4 billion tons, or enough to run a thousand 1-gigawatt fission reactors for 100,000 years.

The tricky bit is how to get the uranium out of the water. One approach developed by the Japan Atomic Energy Institute used polymer mats that would draw the uranium atoms out of solution. But this was very expensive, and a cheaper process that involved doping polymers with amidoxime and then irradiating them was developed at Oak Ridge National Laboratory.

Material designed to capture uranium from seawater as an alternative to land-based mining of the fuel for nuclear power production is tested at PNNL's Marine Sciences Laboratory
Material designed to capture uranium from seawater as an alternative to land-based mining of the fuel for nuclear power production is tested at PNNL's Marine Sciences Laboratory

While this showed more promise, PNNL and Idaho-based LCW took it a step further by taking ordinary acrylic yarn and converting it into a uranium adsorbent. The exact details of the process haven't been released, but PNNL says that the yellowcake sample shows that not only does the technique work, but that the acrylic can be cleaned and reused.

In addition, the technique can even use waste fibers for a greater cost savings and that analysis shows that seawater extraction could be competitive with land mining at present prices.

For the test, the yarn was placed in tanks and seawater circulated over it. As the water flowed, the yarn fibers extracted the uranium by chemically bonding it to a molecule. After processing, the result was five grams of uranium oxide or yellowcake.

Test set up for uranium extraction
Test set up for uranium extraction

"For each test, we put about 2 lb (1 kg) of the fiber into the tank for about one month and pumped the seawater through quickly, to mimic conditions in the open ocean," says Gary Gill, a researcher at PNNL. "LCW then extracted the uranium from the adsorbent and, from these first three tests, we got about five grams — about what a nickel weighs. It might not sound like much, but it can really add up."

Another thing that could add up is the fact that the uranium dissolved in seawater is in a state of pseudo-equilibrium. That is, so long as it remains at its present level, no more will be absorbed from the rocks that form the seabed. If large scale extraction were implemented over thousands of years, that concentration would fall, and more uranium would leach out of the rock. That's a potential 100 trillion tons or enough to satisfy Earth's energy needs for the next billion years ... by which time the human race will probably have moved on.

In addition to uranium extraction, PNNL says that the technique could also be used to clean up waterways contaminated by heavy metals. In the meantime, LCW is seeking to license the technique and is finding funding for large scale tests in the warm waters of the Gulf of Mexico.

The video below shows the recent PNNL tank test.

Source: PNNL

Adsorbent Test at Marine Sciences Laboratory

15 comments
Mr T
It's not getting uranium that's the problem, it's dealing with the lethal waste from reactors. After 60+ years of nuclear energy, this still hasn't been solved, other than to bury it in geologically stable areas and hope for the best. Nuclear is horribly expensive in the total life cycle, several times more expensive than renewables/storage, so what's the point of pursuing nuclear?
martinkopplow
Unlimited? As we all know, nuclear energy always comes with an often neglected downside: Do we really have unlimited strorage space for nuclear waste? Not that I know of. Also, uranium in seawater may be plenty, though certainly not unlimited.
Rustgecko
Extraction of uranium from seawater would be useful if the issue with nuclear power was a lack of uranium. The problem is though - there is no shortage of uranium.
Bob Stuart
Mines are closing for lack of demand. Even by abandoning the witches' brew the reactors produce, they can't begin to compete with wind-pumped hydro storage on cost or construction time. Nuclear was a nice dream, but it turned out to be a nightmare we can't control.
Brian M
Not sure about more Uranium begin much of a plust, fusion technology is what we need with regards to nuclear energy. But the idea of being able to clean up polluted waterways sounds good!
kenkeyessr
The article never mentioned about also filtering out the Gold to help defray the cost. Maybe the Gold is a waste product, please use my yard as a dump site.
flyerfly
There USA has a lot of stock piled uranium, enough for hundreds of years. The problem is we are not designing new and better power plants that are safe. All the existing designs are old and far to large. The problem is to much red tape and not enough innovation because of the red tape. I read of a design years ago that could not theoretically melt down...but it was never made. I would love to have a super safe micro nuke that could heat my house and greenhouse...even if I never got any electricity from it.
StWils
It would be far more useful if the same or a similar approach could extract lithium from otherwise hard-to-refine ores. Right now there is really only one large source of lithium, and it is no where near large enough to support a complete transformation of just vehicle battery needs.
Nelson Hyde Chick
Didn't Fritz Haber go down this rabbit-hole except with gold?
EZ
REMEMBER FUCKUSHIMA!
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