[Manuel_D]

I explained this in the first comment to which you responded [1]. Hydroelectricity is by far the most effective source of energy generation, although it has the distinct disadvantage of being geographically limited. Nuclear power is the most effective dispatchable source after that. Every country that has decarbonized their electricity grid has done so primary through a combination of hydroelectricity and nuclear power. No developed country has deployed a majority wind and solar grid, ever.

1. https://news.ycombinator.com/item?id=33636418

[Schroedingersat]

A nuclear reactor requires about 0.5-1 tonnes of fissile material per GW per year and 3 to 6 years up front. Where is it supposed to come from?

[Manuel_D]

Mined, from the earth. Unlike lithium [1] uranium prices are not experiencing cost overruns. And unlike grid storage, nuclear power already makes up 10% of the world's electricity generation. We only need an 8x increase (another 10% of electricity already comes from hydro) instead of a 1000x increase like we do with grid storage. The thing about nuclear energy is that there's so much energy contained in uranium that more exotic forms of extraction like seawater absorption [2] is feasible. Unfortunately the same cannot be said of lithium. Some estimates predict that lithium reserves may be exhausted by EV production alone [3]. The volume of lithium required for batteries is considerably greater than the amount of uranium needed for fission, which makes seawater extraction non-viable.

1. https://tradingeconomics.com/commodity/lithium

2. https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-s...

3. https://www.lowyinstitute.org/the-interpreter/race-lithium#:....

[Schroedingersat]

> Unlike lithium [1] uranium prices are not experience cost overruns

The 2007 Uranium bubble called. They would like to sell you some lithium futures for delivery on 2028 at costs based on an exponential fit.

> And unlike lithium, nuclear power already makes up 10% of the world's electricity generation. We only need an 8x increase (another 10% of electricity already comes from hydro) instead of a 1000x increase like we do with grid storage.

So after adding the first load for these reactors using hope, then operating them for 15 years, what do we do about the other 12TW of energy? What about the heavy casting facilities needed for thousands of reactor vessels? All the other critical minerals such as around half of the world's chromium production, vast quantities of precious metals and 100s of billions of litres a year of sulfuric acid production to process all the incredibly low grade uranium ore?

> The thing about nuclear energy is that there's so much energy contained in uranium that more exotic forms of extraction like seawater absorption [2] is feasible

I thought things that hadn't been done were completely impossible? Or do we get to acknowledge the TWh scale sodium ion supply chains and 100GW per year electrolyser supply chains that are being built right now as being vastly more realistic?

In any event, either this is a complete fantasy or the Vanadium that you necessarily get in much larger quantities even when using a sorbent that is as selective as possible for Uranium will provide half an hour to two hours of storage for capacity exceeding that of the nuclear reactor every time you refuel it. So at least filling the ocean with broken polymer ribbons will have a minor long term benefit.

[Manuel_D]

> The 2007 Uranium bubble called. They would like to sell you some lithium futures for delivery on 2028.

Was this due to a sudden increase in reactor construction? There was no spike in nuclear power plant operation in 2007. Speculative bubbles are different from actual commodity shortages.

> So after adding the first load for these reactors using hope, then operating them for 15 years, what do we do about the other 12TW of energy?

By "the other 12 TW of energy" you mean other sources of primary energy? The good thing about nuclear power is that it produces thermal energy. This enables things like thermochemical hydrogen splitting which is more suitable to production of hydrogen for transportation fuel and green smelting. The waste heat from nuclear plants can be scavenged for heating and desalination. This is a distinct advantage over wind and solar that do not directly produce thermal energy and have to be converted from electricity to thermal energy.

> What about the heavy casting facilities needed for thousands of reactor vessels?

What about them? The amount of steel needed for reactor vessels is a drop in the bucket of the overall steel market.

> All the other critical minerals such as around half of the world's chromium production, vast quantities of precious metals and 100s of billions of litres a year of sulfuric acid production to process all the incredibly low grade uranium ore?

Again, what about them? Chromium is widely used for stainless steel. Sulfuric acid is widely used for plenty of things like fertilizer production, hydrocarbon refining, and car batteries. An 8x increase in nuclear power wouldn't substantially affect the markets for these resources. Do you have a reason to think that nuclear power production will cause shortages in chromium or sulfuric acid? If so, let's see that analysis instead of just postulating it as fact.

> I thought things that hadn't been done were completely impossible? Or do we get to acknowledge the TWh scale sodium ion supply chains and 100GW per year electrolyser supply chains that are being built right now as being vastly more realistic?

Please read sources before commenting on them: uranium seawater extraction has been successfully performed - not at costs competitive with traditional mining, but as explained in the source the cost of raw uranium is negligible for nuclear power

> In any event, either this is a complete fantasy or the Vanadium that you necessarily get in much larger quantities even when using a sorbent that is as selective as possible for Uranium will provide half an hour to two hours of storage for capacity exceeding that of the nuclear reactor every time you refuel it. So at least filling the ocean will have a minor long term benefit.

This is not how seawater extraction works. The same mass of adsorbent won't collect larger quantities of other elements. The 6 grams of uranium collected per kilogram of adsorbent doesn't turn into a 6 kilograms of material per Kg of adsorbent for a material that's 1000x as concentrated in the ocean. It will fill up faster for a more concentrated element, but you're still retrieving similar amounts of material for the same amount of adsorbent. You have to make 1000x as many trips to collect 1000x as much material, regardless of concentration.

The cost of this extraction is entirely comprised of deploying and retrieving the adsorbent material - letting a buoy sit in the ocean for 2 months instead of 1 week costs nothing. This is why seawater extraction is prohibitively expensive for most applications, uranium's incredible energy density is what makes it a viable application.

[Schroedingersat]

> Was this due to a sudden increase in reactor construction?

Mild delay in a mine opening. A sudden increase in reactor construction would be much worse.

> This is a distinct advantage over wind and solar that do not directly produce thermal energy and have to be converted from electricity to thermal energy.

CSP exists and is going down in price rapidly.

> Sulfuric acid is widely used for plenty of things like fertilizer production, hydrocarbon refining, and car batteries. An 8x increase in nuclear power wouldn't substantially affect the markets for these resources

1kg of Uranium from inkai or husab uses 50-100kg of sulfuric acid. And this is high grade compared to the 600,000 tonnes per year you are proposing using. Doubling world sulfuric acid production is about the right magnitude.

> uranium seawater extraction has been successfully performed

Make up your mind about what is possible and what is impossible. If doing it once to publish a paper and then pencilling out the costs of raw materials counts then we can all just use AlS batteries and go home.

> This is not how seawater extraction works. The same mass of adsorbent won't collect larger quantities of other elements. The 6 grams of uranium collected per kilogram of adsorbent doesn't turn into a 6 kilograms of material per Kg of adsorbent for a material that's 1000x as concentrated in the ocean. It will fill up faster for a more concentrated element, but you're still retrieving similar amounts of material for the same amount of adsorbent. You have to make 1000x as many trips to collect 1000x as much material, regardless of concentration.

> The cost of this extraction is entirely comprised of deploying and retrieving the adsorbent material - letting a buoy sit in the ocean for 2 months instead of 1 week costs nothing. This is why seawater extraction is prohibitively expensive for most applications, uranium's incredible energy density is what makes it a viable application.

Natural Uranium in a burner reactor is not very energy dense in the scheme of things. Much higher than coal, but about the same power output as a similar mass of silicon in a photovoltaic cell (but at 75% CF for 6 years rather than ~15-25% for 30-50).

At ~3g/kg the uranium only has about 10x as much energy as you'd get by burning the polymer or 5x in the current nuclear fleet (wonder how much it takes to make?). There goes the much vaunted EROI unless you get quite a few reuses (hint: you only get a few).

Also what I said is exactly how sea mining works. Please at least try to understand these technologies before pushing them. You get more vanadium than Uranium in any realistic use case https://www.osti.gov/pages/biblio/1234341

The longer you leave it, the more Uranium gets displaced by Vanadium. At 2 months you get 5x as much.

1kg of natural uranium has a power output of about 1-2kW for 6 years and then it's gone. 1kg of vanadium can store 350-650Wh.

Such a simple plan with so few completely deal breaking oversights compared to building sodium ion factories which is already happening and building more pumped hydro which we know how to do.

[Manuel_D]

> at ~3g/kg the uranium only has about 10x as much energy as you'd get by burning the polymer or 5x in the current nuclear fleet (wonder how much it takes to make?). There goes the much vaunted EROI unless you get quite a few reuses (hint: you only get a few).

Except the polymer is re-usable.

> The longer you leave it, the more Uranium gets displaced by Vanadium. At 2 months you get 5x as much.

Until it's saturated, then you can leave it out all you want and it won't collect any more. And I had thought you were referring to lithium seawater extraction - you just tossed out vanadium without actually explaining how you'd use it and I assumed you mistyped lithium.

Unfortunately vanadium redox batteries are not nearly built at the scale of lithium batteries - which are themselves not built at a scale large enough for grid storage - as well as poorer round trip efficiency.

[Manuel_D]

> CSP exists and is going down in price rapidly.

Quite the contrary, CSP fell out of favor because PVs outcompeted it. What is making CSP better? Did mirrors suddenly improve?

> 1kg of Uranium from inkai or husab uses 50-100kg of sulfuric acid. And this is high grade compared to the 600,000 tonnes per year you are proposing using. Doubling world sulfuric acid production is about the right magnitude.

Did you just pick these figures out of thin air? Reduction of uranium in sulfuric acid is nowhere near 100 : 1 ratio. Unless you're talking about 600,000 tons after enrichment, in which case your figure for uranium consumption is off by an order of magnitude. A 1 GW reactor requires 27 tons of uranium per year [1]. The world uses an average of 2,500 GW of electricity meaning we'd need 68,000 tons of uranium fuel per year. The world produces 231 million tons of sulfuric acid annually [2], so even if we run with your un-sourced numbers this only requires an increase of 2-3%.

> At ~3g/kg the uranium only has about 10x as much energy as you'd get by burning the polymer or 5x in the current nuclear fleet (wonder how much it takes to make?). There goes the much vaunted EROI unless you get quite a few reuses (hint: you only get a few).

Except unlike solar power, the nuclear fleet doesn't require vast amounts of energy storage. It produces the amount amount of electricity regardless of sunlight or wind speed.

Here's the future of renewables: We keep building it opportunistically to displace natural gas. But once they saturate markets during peak production, they become far less effective at displacing carbon emissions because most of their energy is wasted.. After some time scratching our heads struggling to build energy storage at anywhere near relevant scales, we realize that dispatchable energy is necessary and we build it the only ways we know how: hydroelectricity where geography permits, and nuclear power. Or we can jump straight to the the last part and skip building a bunch of intermittent generation that will be made redundant in the end anyway.

1. https://world-nuclear.org/nuclear-essentials/how-is-uranium-...

2. https://www.essentialchemicalindustry.org/chemicals/sulfuric...