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## Burning the Rocks?

One cubic meter of “average continental crust” has a mass of about 2700 kg, based on an assumed density of 2700 kg/m3. Depending on who you ask, thorium comprises various fraction of the Earth’s crust. If we take the CRC handbook value of 0.0000096 kg Th/kg crust, there would be (0.0000096)*(2700) = 0.026 kg or 26 grams of thorium in each cubic meter of the average crust of the Earth, and (0.0000027)*(2700) = 7 grams of uranium in each cubic meter. If the thorium and uranium were in the form of metal, then there would be about two cubic centimeters of thorium and about half of a cubic centimeter of uranium in each cubic meter of the Earth’s crust.

Assuming an energy content for thorium of 11 MW*hr/g in a LFTR and an energy content for uranium of 0.035 MW*hr/g in a light-water reactor,

(26 g thorium)*(11 MW*hr/g thorium) = 286 MW*hr of electricity
(7 g uranium)*(0.035 MW*hr/g uranium) = 0.245 MW*hr of electricity

At an electricity price of \$40 to 60/MW*hr of electricity, the value of the energy that would be produced from this material is

(286 MW*hr)*(\$40 to 60/MW*hr) = \$11,000 to 17,000 per cubic meter of crust
(0.245 MW*hr)*(\$40 to 60/MW*hr) = \$10 to 15 per cubic meter of crust

One cubic meter is 6.3 barrels, and a barrel of Texas light sweet crude oil fetches about \$100 (on or about 3/7/2012), thus an equivalent volume of crude oil would be worth \$630.

At these prices the value of the energy produced by the thorium in an average cubic meter of the Earth’s crust in a LFTR is worth (11000 to 17000)/(630) = 17 to 27 cubic meters of Texas light sweet crude.

The highest grade of coal is anthracite coal, and one cubic meter of anthracite would have a mass of 1300 to 1400 kg. In June 2008 anthracite was priced at \$150/short ton (short ton = 2000 lb) or \$0.165/kg. This would imply a value of \$215 – 230/m3 of anthracite coal.

At these prices the value of the energy produced by the thorium is an average cubic meter of the Earth’s crust in a LFTR is worth (11000 to 17000)/(220) = 50 to 77 cubic meters of anthracite coal.

By comparison, the value of the electricity produced by the uranium in a cubic meter of crust, if used in a light-water reactor, is one-fiftieth the value of the equivalent volume of crude and one-seventeenth the value of anthracite coal. It would be much better to “burn the rocks” for crude or coal than for uranium, but far more valuable to get thorium than crude or coal.

## 11 thoughts on “Burning the Rocks?”

1. Chris says:

It makes me so sad to know how great the world could be if we employed LFTR technology now, and if we had simply carried on the work that was done in the 1960's.

Nobody seems to know anything about thorium, t's entirely off the radar of the average person and that's very frightening given our energy situation.

2. Greg says:

Chris, the lack of understanding and support is indeed sad and unfortunate. It is even sadder that it is all due to Executive Orders by Presidents Carter and Clinton, and supported by President Obama to placate some environmental groups and ensure their vote in federal elections.

3. Al Vilcius says:

Certainly an interesting and compelling calculation. However, it may be even more interesting in the context of a "rocks to rocks" analysis along the lines of the now discredited "dust to dust" comparison between Hummer and Prius which circulated as a sort of urban legend.

I think public awareness and support for good science can be gained through the right urban legends. Any "rocks to rocks" analysis would, of course, be enormously complicated and require many assumptions that could serve as legitimate discussion points, as well as highlighting many flaws in standard economic models that fail to quantify various human biases. Nevertheless, it may be worthwhile to attempt a few variations.

4. Jeff S says:

This is an interesting write-up. Can I make a request? How does the math work out if, instead of assuming LEU in a light water reactor, we assume that we burn ALL of the uranium in a fast-breeder reactor? My understanding is that we should be able to expect to get, roughly, 200X more energy out of uranium in a fast reactor, than we do in a light reactor, which makes the value of that Uranium much higher, doesn't it?

In any case, this is all a rather abstract discussion since we still have large amounts of higher-concentration ores for both Thorium and Uranium, so it doesn't make much sense to mine 'average crust' until we've depleted the high grade ores. Still, this does show that in some distant future, there will still be plenty of fuel left when the HGO's are basically all gone, and that's useful to explain to folks who say nuclear isn't renewable.

Also, with respect to Uranium, the oceans provide a vast reserve of U.

5. Uncle B says:

China's "Big Secret" is the successful fissioning of Thorium! Bonus: no high waste fuel disposal costs either! China also already knows how to stream waste from Uranium fissioning schemes into their CANDU reactors as well as Thorium fuel and uranium ores – Even Bill Gates became excretable from the American Nuclear Establishment and had to seek Chinese Scientists for his new reactor designs, now under way or perhaps even in use in China today? The truth lies somewhere just beyond the American "Chosen People" mythologies and is written in Mandarin and quite likely will never be published at all.
CANDU reactors even in the 1950's could and did consume Thorium, and even raw uranium ores for fuel! With modern instrumentation, and a few basic alterations, fine tuning if you will, China can make these reactor marvels really perform well.
Calculations on this page are very revealing. I see vested interests, "sunk money" and corporate shenanigans at the base of the lack of successful commercial use of Thorium as a nuclear fuel. I also see the seeking of plutonium for bomb purposes another major factor.
Watch closely now as electric bullet train networks and their human infrastructures are "daisy-chained" across the vast Pan Eurasian land mass and even by "chunnel" ( channel tunnel) to the African continent, even into Great Britain, already.
America, stuck on stupid, allowing the ferment of Capitalism to rise and drown her in her own economic sewage with a concentration floating ever upwards of Uber Rich, even their excrement suffocating the largest part of her population, loses to China today as China moves into co-operative economic realities in South and Latin America, where they will exercise Thorium, cheap and safe fissioning technologies, electric rechargeable car systems, electric bullet train networks designed compatible to "Daisy-Chaining" up to U.S. borders at least, and most certainly with full continental design in mind. http://www.theoildrum.com/node/4971 tells where the U.S. got off the track to true greatness, and only God knows why.

6. Kirk Sorensen says:

Jeff if you burned all the uranium in a fast-spectrum reactor you would recover about a fourth of the energy from a cubic meter of average crust as in the thorium case.

7. Jeff S says:

Kirk, thanks for the reply. Well, once you get to 1/4, it at least compares favorably to fossil fuels. I figure that if you are processing crust *anyhow*, if the extra cost to extract uranium isn't too much, you might go ahead and just do it anyhow, and pull both out. If there are fast reactors, then you have a market. If there's not, then you probably wouldn't bother.

8. TerjeP says:

Chris – I spoke to a former Australian energy minister last night (Nick Minchin) at a function. It was only for about ten minutes. He seemed to be well aware of Thorium and LFTR and thought it all looked very promising. There are probably a lot more people aware of the LFTR potential than it seems. However awareness won't translate into development investment unless there is some viable vehicle through which that can happen.

9. Steven Brown says:

This essay exposes the folly of continued reliance on breaking chemical bonds for energy, while the energy that can be released by breaking nuclear bonds is many times greater. The traces of thorium found in coal can provide 18 times the energy obtained from the coal, but it gets spewed into the atmosphere along with other pollutants.

10. David Mohre says:

Let's not forget the early days of US commercial nuclear power. Indian Point Unit 1 operated with a blended Thorium cycle for at least 1 operating cycle. It was well before my time, so I have no first hand knowledge of the results of that operation.