Again, there's a difference between what's technically possible and what's likely to happen, or accomplished most easily - or else we'd have that global supergrid of solar panels with everything electrified already.

In the particular case of the Casale process, you can just look at how all the endothermic and exothermic reactions add up to see why we don't often make synthetic gas from electrolysing water and combining with atmospheric nitrogen.

Corn-based plastic isn't exactly widespread, either.

There's a difference between what's technically possible, or possible in theory on paper, and how things turn out in practice. Which is why we can't compare uranium with fossil fuels and renewables on a simple energy-out basis. There's a lot more to it all.

Comparing them by energy content is as meaningful as comparing them by weight or spectral signature.

I can't chuck a chunk of uranium in a car. I can't put oil in a little radiative reactor and send it to Jupiter to power a space probe.

They're different things. Just as our vast numbers of cars couldn't run without all the millions of kilometres of roads we've put in - all that oil would be useless for transport - so too uranium is useless without reactors, converting everything to electricity, and so on.

The change is non-trivial, which is what makes a simple comparison of energy content meaningless.

someone needs to show that it can be done at scale at reasonable cost, and that it can be maintained (not wear out immediately).

If one solar cell is 20% efficient nobody questions that a million identical solar cells will be 20% efficient. Why would it wear out immediately at large scale? If specific engineering problems show up they will be resolved as they were with early steam engines, aircraft, cars, windmills etc.

I support a demonstration facility, as we are doing with demonstration solar plants that are not economically justified, but there is no evidence that it is not feasible.

What collection scale are you asserting will achieve the necessary amount of uranium to sustain the world's reactors?

Perhaps you missed this part.

Sea water uranium does not have to supply all of our uranium in order to cap the uranium price at $150/pound. It only has to replace the percentage of land based uranium sources that cost more than $150/pound, and that percentage is zero for the foreseeable future.

A per-person basis is deceiving

Why?

Personally my eyes tend to glaze over from all the big numbers thrown around. One or two zeros more or less doesn’t seem to make much of an impression, but I understand this.

If all our electricity came from coal we would burn 1.14 million pounds of coal per 80 year lifetime (13,400 lb/yr/person) and release 2.4 million pounds of CO2 plus 200,000 of pounds of toxic solid waste.

If all our electricity came from fission using today’s technology we would need 58 pounds of uranium per lifetime, of which only about 6 pounds would actually get into a reactor, resulting in about 10 pounds of spent fuel containing 5.4 ounces of fission products.

I want to know how many miles of collector need to be suspended in the currents of the world, how they will be suspended, how much energy it takes to make them, how much energy is required to deploy/harvest/redeploy them, and how the logistics for harvesting and redeploying them will be accomplished.

Consider this quote;

The braid type adsorbent was pulled up after soaking in seawater for 60 days… The lowest cost attainable now is 25,000 yen with 4g-U/kg-adsorbent used in the sea area of Okinawa, with 18 repetitions

This works out to six 60 day cycles per year. At 4g per cycle that is 24g / kg adsorbent / year. At this rate we only need 41kg of adsorbent to produce 1kg of uranium per year.

25,000 yen/kg equals $238/kg, equals $108/pound.

To make all U.S. electricity with our primitive steroidal submarine reactors, we need 0.72 pounds (330gm) of uranium / year / person.

We will need only 13.6 kg (30 pounds) of membrane per person using today’s primitive reactors.

Can you think of any way that hanging 30 pounds of adsorbent in sea water could cost more than digging up 13,400 pounds of coal each year and shipping it half way across the country?

Even if these cost estimates are off by a factor of 5 or 10 it is still cheaper than natural gas.

Using breeder reactors we need 0.35 pounds (159 gm) of uranium / 80 year lifetime. To produce all our electricity from fission at the U.S. rate using seawater uranium in breeder reactors our 0.35 pounds per lifetime will cost $37.80 / lifetime, 47 cents per year. We will need only 83g (0.18 pounds) of membrane per person

In fact the technology is so good that Leeuwen did not complete his cost estimate of sea water uranium. Consider his analysis on extracting uranium from sea water, page 57 of this October 2007 report.

http://www.stormsmith.nl/report20071013/partD.pdf

In this analysis the most recent work considered was published in 2001 by Sugo on polymer adsorption of uranium from seawater.

http://npc.sarov.ru/english/digest/132004/appendix8.html

A… He ignores the more recent 2006 report, [Confirming Cost Estimations of Uranium Collection from Seawater- Assessing High Function Metal Collectors for Seawater Uranium ]

http://jolisfukyu.tokai-sc.jaea.go.jp/fukyu/mirai-en/2006/pdf/4-5.pdf

It describes the experimental results from testing improved technology. It concludes;

“The lowest cost attainable now is 25,000 yen ($280/kg) with 4g-U/kg-adsorbent used in the sea area of Okinawa, with 18 repetition uses.”

B… The latest technology uses braided rope like adsorbents that can be deployed in single strands or long loops for continuous processing. Leeuwen prefers to analyze the older technology of the 2001 study that packs the adsorbent in metal cages that are responsible for a large fraction of the cost and weight. The study describes three techniques to deploy the cages, one is much cheaper than the other two. Leeuwen discusses the most expensive option.

He assumes that the cages will be shipped to a distant reprocessing plant, running up the transportation cost and emissions. In reality the cages would be reloaded at sea, as in the crab industry.

C… By eliminating the cages and moving the extraction process onboard the adsorbent deployment ship, the transportable product mass is reduced by a factor of a few thousand making those transportation emissions negligible.

D… Leeuwen likes big numbers. He describes a single plant that would generate 1/7 of the world’s uranium consumption.

E… After beginning his analysis of Sugo 2001 he introduces a great deal of superfluous information from old reports evaluating a different technology, for example.

“Estimates of the cost of deriving uranium from seawater range between approximately $1000 and $25000 per kg uranium.”

F…He does not complete his cost estimate of the Sugo technology, but includes the authors estimate of $280 / kg in a table with the older/higher estimates saying, “The cost estimates by Sugo et al. may be low by a factor of at least 10.”

He ignores statements by the author indicating the potential for improvement, for example.

“The calculated stoichiometric chemical uranium adsorption capacity of this adsorbent is 500 g per kg adsorbent based upon the concentration of amidoxime groups”

“It is clear from experiments that metal adsorption rate increases roughly 3-fold above 10°C.”

Most new technologies improve with time and his own table, D29, shows that the estimated cost of sea water uranium has dropped an order of magnitude in 30 years.

G… He ignores the other valuable products that could be extracted along with uranium, offsetting a portion of the cost.

H… The adsorbent concentrates the uranium from 3.3 parts per billion in seawater to 4 parts per thousand in the adsorbent, a concentration factor of 1.2 million.

On page 55 Leeuwen has a flow diagram showing 5 waste streams. He writes;

“A five-stage process with an assumed yield of 80% of each stage, would have an overall yield of 33%. If each stage has a individual yield of 70%, the overall yield would be 17%. A rough estimate of the overall yield of a five-stage extraction process, excluding the first stage (adsorption from seawater), may be in the range of 20-30%.”

Any chemical process engineer who recommends a process that throws away 70%-80% of the product AFTER concentrating it by a factor of 1.2 million would be laughed out of the building, pink slip in hand. The so called waste streams would be recycled.

I… Most importantly he does not explain that at a few hundred dollars / kg the uranium cost per kWh is lower than our cheapest fossil fuel, coal. Even at 10 times Sugo’s estimate, the cost of uranium per kWh would be about the same as natural gas, but the cost trend for natural gas is going up while that for sea water uranium is going down.

J… Gen 4 reactors will reduce uranium requirements / kWh by a factor of 60-100. Gen 4 plants using sea water cooling could extract all their fuel directly from the condenser cooling water.

Leeuwen’s strategy is to create a straw man based on irrational assumptions that will result in the desired analytical conclusion, and then applying that conclusion to all possible designs, declaring them all impractical.