The uranium in a cubic meter of seawater, used in current reactors, produces electricity (~0.1 kWh) worth less than even simple processing of a cubic meter of seawater costs. If seawater processing cost as much as desalination, and fuel was half the electricity cost, that’d be $10/kWh. Well, at least I guess it’s less dumb than mining He3 from the moon.
The process of harvesting uranium from seawater is not about desalination. One website describes the process as:
Scientists have long known that uranium dissolved in seawater combines chemically with oxygen to form uranyl ions with a positive charge. Extracting these uranyl ions involves dipping plastic fibers containing a compound called amidoxime into seawater. The uranyl ions essentially stick to the amidoxime. When the strands become saturated, the plastic is chemically treated to free the uranyl, which then has to be refined for use in reactors just like ore from a mine.
How practical this approach is depends on three main variables: how much uranyl sticks to the fibers; how quickly ions can be captured; and how many times the fibers can be reused.
In the recent work, the Stanford researchers improved on all three variables: capacity, rate and reuse. Their key advance was to create a conductive hybrid fiber incorporating carbon and amidoxime. By sending pulses of electricity down the fiber, they altered the properties of the hybrid fiber so that more uranyl ions could be collected.
If you leave the fibers out in the ocean and just wait till they can be harvested you aren’t processing cubit meters of seawater in any meaningful way, so I don’t see a good reason to compare it to desalination prices.
I’m aware of such proposals. You’d have to leave the fibers out for a really long time without pumped flow. They’d accumulate stuff on them. The concentration achievable is fairly low. The special fibers are expensive. Putting them out and collecting them is expensive. This would all end up being even more expensive than pumping seawater.
Also, amidoximes are susceptible to hydrolysis; many of them would convert to ketones in seawater eventually.
The process of harvesting uranium from seawater is not about desalination. One website describes the process as:
If you leave the fibers out in the ocean and just wait till they can be harvested you aren’t processing cubit meters of seawater in any meaningful way, so I don’t see a good reason to compare it to desalination prices.
I’m aware of such proposals. You’d have to leave the fibers out for a really long time without pumped flow. They’d accumulate stuff on them. The concentration achievable is fairly low. The special fibers are expensive. Putting them out and collecting them is expensive. This would all end up being even more expensive than pumping seawater.
Also, amidoximes are susceptible to hydrolysis; many of them would convert to ketones in seawater eventually.