Thorium plants also have the unfortunate characteristic of not existing in deployable commercial form (and only very barely in experimental form).

CANDU reactors support mixed Uranium and Thorium fuel.

"CANDU can also breed fuel from the more abundant thorium. This is being investigated by India to take advantage of its natural thorium reserves." [1]

[1] https://en.wikipedia.org/wiki/CANDU_reactor

Thanks, noted.

I think the reason they don't go the Thorium route is that Uranium is just so abundant -- and so incredibly energy dense -- there's not a hugely compelling reason to switch to Thorium.

Thorium reactors are breeders. The Th gets converted to 233U. But breeders of any kind are uneconomical.

Why is that?

They require an extra separation step (removing newly bred material from spent fuel, or removing fission products from molten salt). This is more expensive than just doing nothing to the spent fuel.

In the past, the idea was that nuclear would be cheap, but would run into uranium supply constraints, so breeding would save money. But that's not how it turned out. Nuclear was expensive not because of fuel, but because of the cost of the power plants. Uranium prices remain low. Also, the move to gas centrifuges reduced the energy consumed in uranium enrichment by a factor of 50.

Thanks.

My understanding is that uranium supplies remain constrained --- fewer than two decades if supplying 100% of total global generation, say. Price doesn't tell you much about total resource stock.[1] That's based on terrestrial sources. Seawater U separation in theory would extend resources considerably, but remains unproven at scale.

Thorium, other disadvantages notwithstanding, is at least more plentiful.

I'll note I'm not generally a fan of nuclear, though don't rule out any contributory role.

________________________________

Notes:

1. I'd argue generally that nonrenewable natural resource pricing theory, dating to Ricardo, but especially Hotelling, is entirely flawed. Much of it under suspicious circumstances.

Yes, but the "supplying 100% of global generation" doesn't have any bearing on current reality.

Anyway, this argument for thorium isn't something customers would care much about. It's basically "thorium would not suck as much as uranium-fueled burner reactors do if uranium gets much more expensive" rather than "nuclear power is more attractive now if we use thorium". The customer response to "nuclear as currently implemented fails badly if uranium runs out" is going to be "use something other than nuclear".

Late response, my apologies.

At some point we've got to address the question of how much energy is supplied to how many people and for how long.

Population is expected to rise for at least another 30-80 years, to between 9 and 12 billions by most estimates. These may not see US levels of energy access, but most authors project per capita energy wealth roughly comparable to present day European levels, largely as electricity. This represents multiples of present generating capacity.[1]

And energy represented by virtually any nonrenewable stock, including most fissionanbles, is finite. That's before allowing for technical limitations, concerns, wastes, risks, or other impacts.

When the U.S. was first transitioning from wood to coal, roughly 1860--1880, then-known reserves were calculated as sufficient for at least one million years at then-present rates of consumption.[2] The problem, of course, is that rates of consumption increased somewhat, by a greater rate than those of new coal discoveries. I can remember in the 1970s National Geographic adverts assuring readers that America's coal reserves were good for another 1,000 years, already a thousandfold reduction from 100 years prior. Today official estimates tend to run 200--300 years, though pessimistic ones suggest scarcely a century.[3] That's roughly 10,000 times sorter than initially anticipated, thanks largely to the Jevons Paradox: low-cost goods and increased efficience stimulate demand.

And all this before acknowledging that we simple cannot burn much more of the stuff.

So, no, I don't buy that "supplying 100% of global generation doesn't have any bearing on current reality.", as even a small fraction of a growing number, most especially an exponentially growing one, remains a large number.

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Notes:

1. 1991 per capita use, 287.8 GJ US, 75.3 GJ world, 123.6 GJ Europe. bp Statistical Review of World Energy 2020, p. 11. At 123 GJ * 12 billions souls, total global energy demand would be 1,476 EJ, vs. 584 EJ consumed 2019, a 250% increase. Total 2019 electric generation was 27,005 TWh, or 97.2 EJ, 16.6% of total global energy consumption. That works out to 3.46 MWh/capita, or about 395 W continuous per person.

2. Henry Erni, Coal oil and petroleum: their origin, history, geology, and chemistry (1865), p. 14. https://archive.org/details/coaloilpetroleum00erni/page/14/m...

3. BP's 2020 report gives an R/P ratio, reseves vs. production, equivalent to years supply at present consumption, of 390 years. This is an increase, though almost entirely due to reduced extraction, down from 22.27 EJ in 2011 to 14.30 in 2019. Consumption has fallen by more.

If we're talking about ultimate limits on Earth, solar is probably better than nuclear, just from direct thermal pollution. Solar causes a moderate increase in sunlight absorbed, but otherwise just moves solar energy around. If the albedo of the ground on which the solar modules were installed was less than the efficiency of the modules, there is no local heating, although the produced power gets degraded to heat eventually elsewhere as it is used. For every kWh of power produced, nuclear adds 3 kWh of heat to the biosphere (1 from the power produced, 2 from the waste heat of the reactor.)

(This is really a reflection of the difference between primary energy, which today is largely thermal, and delivered energy, which is largely work or chemical. The conversion to renewable energy will greatly reduce the importance of thermal energy conversion, and will not require a 1-1 replacement of today's primary energy use.)

It's not at all clear energy use will grow that much more. Lesser developed countries will use more, but in advanced countries energy use has plateaued. We are currently very far away from limits on solar energy imposed by shortage of sunlight. The Earth is hit by 100,00 TW of sunlight; global primary energy use is 20 TW.

If we're talking about limits OFF the Earth, solar is vastly more abundant than uranium (or, for that matter, artificial fusion, since the Sun fuses starting with ordinary hydrogen, not comparatively rare isotopes/elements like deuterium, lithium, or boron.)

I tend to agree generally WRT solar.

The usefully convertable fraction of solar on Earth may be far closer to present or anticipated energy demands than is commonly thought. Panel efficiency, spacing factor, lifetime, capacity factor, storage requirements, essential fuel-based needs (marine shipping, powered flight, mobile power, remote reserve generation & thermal), process energy (steel coking, Haber-Bosch, etc.) leave some large holes and very uncomfortable margins remaining.

The alternatives to solar are either secondary or tertiary options (biofuels, wind, wave) and hence, more limited, or comparatively finite (geothermal, possibly our best non-solar option, tidal).

I do largely suspect that humanity's future will be principally solar powered. The question is largely of how much energy and in what forms it will be available. And aagain, demographic trends and expectations shade strongly against pleasant transition.

I find Vaclav Smil's and the late David MacKay's works quite illuminating.

There was a commercial thorium reactor in Germany, which was a financial disaster:

https://en.wikipedia.org/wiki/THTR-300

That was also a pebble bed reactor. The kind of reactor generating all of the latest hype is a molten fuel salt breeder reactor. There's a really substantial difference between the two and the MSRE was basically a mock up of the core running on Uranium fuel salt that would have been generated in a fertile Thorium blanket salt around the core and been reprocessed into the fuel salt.

Pebble bed reactors have tons of drawbacks that don't apply to most modern Thorium reactor proposals. The biggest drawbacks to proposals like e.g. LFTR is corrosion risks which were largely addressed by the MSRE ages ago, and the chemical reprocessing equipment which again is mostly a chemical engineering problem more so than a nuclear engineering one.

To place it in the context of this compressed energy storage, when does the plant expect to be commercial viable through the method of buying energy cheap, storing it, and selling it expensive?

As far as I can find information, this plant is built on 30 millions given from the government. They have also got 17 millions from an equity round and 20 millions from a asset manager that supports building out clean-energy infrastructure.

In order to be commercial viable they need a significant overproduction in the energy grid from wind and solar which enable the company to buy cheap energy during peaks and sell it expensive during lows, and the difference need to be significant enough to pay both the energy loss, the operation cost and the investment costs. Wind and solar will also not over saturate the market beyond what is commercial viable for them, putting a short-term limit on how cheap the price can go during peaks.

This is millions, while anything nuclear is measured in billions. And nuclear technology, including thorium, is decades old technology, unlikely to see the kind of rapid gains less mature technology frequently exhibits.

The tens of millions is a pretty cheap deal compared to nuclear power, which needs billions to get the ball rolling (and that's if it completes on budget)

Its only a good deal if it produce profits. I rather have the government take a billion dollar cost in the energy sector that later turn a profit than a millions dollar cost that don't.

If neither can make a profit then that says something about the energy market. Turn off the fossil fueled alternative (or incrementally add a carbon tax until fossil fueled become commercial nonviable) and let see if the market price adjust to the point where the profitability of either goes into the green.

> I rather have the government take a billion dollar cost that later turn a profit than a millions dollar cost that don't.

Surely that ought to depend on how much profit it generates. If it only generates a few millions in profit you're still down on your money.

The first step is to be profitable, ie that revenue is higher than costs, and the second is that the rate of profit exceeds the investment cost over its lifetime.

A project is not commercial viable if it lacks either. Currently I have not heard of a single energy batter project that is profitable. The cost of buying energy together with employees and maintenance is significant above that of the revenue that they can get out. The hope is that if there is enough overcapacity in the future from wind and solar then the price will be low enough, and the electricity price during lows is high enough, that they could then make a profit. Nuclear in turn has seen mostly a drop in revenue while cost has only increased.

Choosing between two nonviable commercial options is a bad choice. I do however want an energy grid that is emissions free so one way or an other the economics need to change. Increasing the electricity price by kicking out fossil fuels is a good bet to help both technologies to be more commercial viable. Convincing wind and solar investors to over saturate the market and crash the price during peaks would be an alternative. Time will tell.

As a earlier article suggested, we need to actually do all of it if we want to reach the climate change goals. Pump more money into researching cheaper and more effective production of wind and solar plants that can saturate the market, research more effective battery solutions, kill fossil fueled power plants by aggressively tax them to death, and expand more nuclear plants.

A big problem with batteries as currently envisioned is that under a centralized utility model they don't "generate profit" per se.

Puerto Rico has post-Maria microgrids that are more resilient than the old utility model was to natural disaster, but they're making PREPA's financial situation worse, not better.

Thorium produces just as much fission product waste as uranium.

And any thorium reactor is going to have to include 238U in it, or else the effectively high enriched 233U it DOES contain would be an unacceptable diversion risk (even with 232U contamination). That means it's going to produce more plutonium than you are letting on.

> The Netherlands just brought the first thorium powered plant online since the fifties.

Just to be clear, because one might get the wrong impression from how that was formulated (at least I know I did): what they have is a small test reactor, not a commercial electricity generating plant.