Nuclear Power Becomes Completely Renewable With Extraction Of Uranium From Seawater

by James Conca

America, Japan and China are racing to be the first nation to make nuclear energy completely renewable. The hurdle is making economic the extraction of uranium from seawater, because the amount of uranium in seawater is truly renewable as well as inexhaustible.

New technological breakthroughs from DOE’s Pacific Northwest (PNNL) and Oak Ridge (ORNL) national laboratories have made removing uranium from seawater economically possible. The only question is – when will the source of uranium for our nuclear power plants change from mined ore to seawater extraction?

Researchers at PNNL exposed this special uranium-sorbing fiber, developed at ORNL, to Pseudomonas fluorescens and used the Advanced Photon Source at Argonne National Laboratory to create a 3-D X-ray microtomograph to determine microstructure and the effects of interactions with organisms and seawater. Courtesy of PNNL

Researchers at PNNL exposed this special uranium-sorbing fiber, developed at ORNL, to Pseudomonas fluorescens and used the Advanced Photon Source at Argonne National Laboratory to create a 3-D X-ray microtomograph to determine microstructure and the effects of interactions with organisms and seawater. Courtesy of PNNL

Nuclear fuel made with uranium extracted from seawater makes nuclear power completely renewable. It’s not just that the 4 billion tons of uranium in seawater now would fuel a thousand 1,000-MW nuclear power plants for a 100,000 years. It’s that uranium extracted from seawater is replenished continuously, so nuclear becomes as endless as solar, hydro and wind.

Specifically, this latest technology builds on work by researchers in Japan and uses polyethylene fibers coated with amidoxime to pull in and bind uranium dioxide from seawater (see figure above). In seawater, amidoxime attracts and binds uranium dioxide to the surface of the fiber braids, which can be on the order of 15 centimeters in diameter and run multiple meters in length depending on where they are deployed.

After a month or so in seawater, the lengths are remotely released to the surface and collected.  An acid treatment recovers the uranium in the form of a uranyl complex, regenerating the fibers that can be reused many times. The concentrated uranyl complex then can be enriched to become nuclear fuel.

Testing at facilities like PNNL’s Marine Sciences Laboratory in Sequim, Washington shows that these new fibers have the capacity to hold 6 grams of uranium per kilogram of fiber in only 50 days in seawater. These advances have reduced the cost of this method by a factor of four in just five years. But it’s still over $200/lb of U3O8, twice as much as it needs to be to fully replace mining uranium ore.

Fortunately, the cost of uranium is a small percentage of the cost of nuclear fuel, which is itself a small percentage of the cost of nuclear power. Over the last twenty years, uranium spot prices have varied between $10 and $120/lb of U3O8, mainly from changes in the availability of weapons-grade uranium for blending down to make commercial fuel.

However, the big deal about extracting uranium from seawater is that it makes nuclear power completely renewable. As renewable as wind.

Hundreds of lengths of U-extracting fibers are anchored in the sea for a month or so until they fill with uranium. Then a wireless signal releases them to float to the surface where the uranium is recovered and the fibers reused. It doesn’t matter where in the world the fibers are floating. Source: Andy Sproles at ORNL

Hundreds of lengths of U-extracting fibers are anchored in the sea for a month or so until they fill with uranium. Then a wireless signal releases them to float to the surface where the uranium is recovered and the fibers reused. It doesn’t matter where in the world the fibers are floating. Source: Andy Sproles at ORNL

Uranium is dissolved in seawater at very low concentrations, only about 3 parts per billion (3 micrograms/liter or 0.00000045 ounces per gallon). But there is a lot of ocean water – 300 million cubic miles or about 350 million trillion gallons (350 quintillion gallons, 1,324 quintillion liters). So there’s about 4 billion tons of uranium in the ocean at any one time.

However, seawater concentrations of uranium are controlled by steady-state, or pseudo-equilibrium, chemical reactions between waters and rocks on the Earth, both in the ocean and on land. And those rocks contain 100 trillion tons of uranium. So, whenever uranium is extracted from seawater, more is leached from rocks to replace it, to the same concentration. It is impossible for humans to extract enough uranium to lower the overall seawater concentrations of uranium over the next billion years, even if nuclear provided 100% of our energy and our species lasted a billion years.

In other words, uranium in seawater is completely renewable. As renewable as solar energy. Yes, uranium in the crust is, strictly speaking, finite. But so is the Sun, which will eventually burn out. But that won’t begin to happen for another 5 billion years. Even the wind on Earth will stop at about that time as our atmosphere boils off during the Sun’s initial death throes as a Red Giant.

According to Professor Jason Donev from the University of Calgary, “Renewable literally means ‘to make new again’. Any resource that naturally replenishes with time, like the creation of wind or the growth of biological organisms for biomass or biofuels, is certainly renewable. Renewable energy means that the energy humans extract from nature will generally replace itself. And now uranium as nuclear fuel meets this definition.”

So, for all practical purposes, solar, wind, hydro and nuclear are all renewable. It’s about time society recognized this and added nuclear to the renewable portfolio.


James ConcaDr. James Conca is a geochemist, an RDD expert, a planetary geologist and professional speaker.  He is also a regular contributor on Forbes. Follow him on Twitter @jimconca and see his book at Amazon.com

5 thoughts on “Nuclear Power Becomes Completely Renewable With Extraction Of Uranium From Seawater

  1. Nicolas Hernandez

    Jim, does this mean anyone who lives in a state with a Renewable Portfolio Standard can be a party with legal standing to force their state to interpret their RPS law to include nuclear power as renewable and therefore a beneficiary of the RPS? If so, then call up the Nuclear Energy Institute (the commercial nuclear power industry’s lobbying organization) as I am sure they have a few good lawyers who would only be too happy to pursue this, haha. But really I am serious let’s do this!

  2. William C. McKee

    Dear Sirs, I see that this process is extracting quite economically uranium from seawater. But keep in mind that we are generally interested in only the U-235 isotope, the U-238 isotope requires dealing with Pu-239, a problematic substance that the Greens (looking for renewable energy will much object to).

    However can this process be extended to the element Thorium. I concept at least the isotope Th-232 can power up (along with a starter charge of U-235) a Molten Salt Thorium Reactor. An associate isotope U-233 is produced and produces energy. The US government gamely tried to make a mixture of U-233 and other isotopes into a nuclear bomb. The very poor yield was such a disappointment that all R&D on Thorium was removed from the budget. Until China recently took an interest in the MSTR that the US invented in the 1960’s — and pushed off the table of research, and onto the floor, for whoever else wanted to use it.

    From a web table: “Mineral Makeup of Seawater”

    Uranium 0.0016 ppm in seawater.
    Thorium 0.0005 ppm in seawater.

    The part of Uranium that we actually want is U-235 about 0.7 % of bulk Uranium.
    Or, (0.0016)*(0.7/100) = 0.0000112 ppm of seawater.
    As you can easily see there is 0.0005/0.0000112 = 44.6 times as much usable Th-232 as there is usable U-235 in the ocean.

    Along with all of its other advantages, such extracted Thorium would have an approximate market value of:
    (200 $/pound)/(44.6) = 4.48 $/pound.

    That is [half] of the least ever reported cost of bulk uranium ore. And that ore needs both chemical and isotopic processing to be of any use for a reactor. A whole lot of added expense.

  3. Rothwell

    This is nonsense economics. I’ve been to Sequim. This technology might be economically available when lower cost uranium runs out. Note that natural uranium and enrichment are economically intertwined. Together they are a large part of variable costs after the monthly mortgage payments are made. They have a large impact on profits. So please stop stating that they a small portion of levelized nuclear power costs!

  4. Jim Conca

    Good point, Scott. In fact, nuclear is increasing, but mostly elsewhere in the world. China is planning on 400 new reactors by 2050. The U.S. will lose a few add a few over the next 15 years, then will slowly expand with new reactor designs like SMRs.

  5. Scott Medwid

    I’m attending the “After Fossil Fuels: The Next Economy” conference on the transition to a clean energy economy. Oct. 6,7&8 at Oberlin College. Lots Of WWS only people attending. I will be referencing this good news !

    I just talked about this subject with an OC environmental sciences major this past weekend who did not believe advanced atomic power was even being pursued any more. He was not of the opinion that nuclear power was a clean energy source.

    Much to learn these young ones!

    Keep up the posts Mr. Conca Thank you

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