About LFTR – Liquid Flouride Thorium Reactors

You wouldn’t use a 20 year old cellphone, so why are we using 20+ year old nuclear technology?  The curious reason we are, is because it works, but we could be doing so much better.

Here is the short overview on LFTR and Thorium (the fuel of the future):



– Element 90, found as Thorium 232 in nature, is 4 times more common than Uranium and about 200-400x more common than U-235, the fuel we burn in Light Water Reactors (LWRs) in the US and much of the world.  That’s just the start…

– Thorium is naturally radioactive like uranium, and has a half-life equal to the age of the universe (about 15 billion years) so it will be with us for a long time

– It is found in large quantities in “Rare Earth” mines, which are rare in the US because they dig up Thorium.  Thorium is (weakly) radioactive, and US law requires it be treated as a radioactive waste and buried.  Too much Thorium in a rare earth mine makes it unprofitable, but it is these rare earth mines that bring up the high technology metals we need in society today, such as Neodymium for magnets (think generators and motors).

– A LWR (Light Water Reactor) in the US burns about 0.5%-5% of the fuel put in it, the remaining is disposed of as unburned fuel as part of the radioactive waste.  A LFTR on the other hand, running from Thorium could burn 100% of the fuel

– Because it can all be consumed, if you held a marble a little over an inch across (~3 cm) made of Thorium, it could power your entire (western world) needs for your entire life. (more:  http://www.youtube.com/watch?v=qbGZ_Y-xkPM)

– The “waste” products are far less than that of the Light Water Reactor technology used today.  Also, the amount of mining is far less – and a natural result of a rare earth mine (see above).  (more: http://energyfromthorium.com/2007/01/09/uranium-vs-thorium-mining-processing-waste-generation/ and http://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor#Economy_and_efficiency)

– The byproducts of a LFTR are radioactive, but contain few “transuranic” elements – which would be radioactive for a very long time.  Instead, much of the “waste” could be recycled into useful products after a month or a few years of cooling off, and by about 100 years, much of the radioactivity is gone.

– There is less risk of proliferation with LFTR (Thorium) fuel, since Thorium doesn’t fission in of itself, and stolen active LFTR fuel would contain U232 (a natural byproduct of the LFTR process, not required to be added).  U232 is very radioactive and would damage electronics and irradiate the people stealing it, and make any stolen material easy to find.


LFTR – Liquid Fueled Thorium Reactor  (A molten-salt reactor using thorium)

– A LFTR is a different kind of reactor.  It was invented during the 1950s and 1960s in Oak Ridge Labs, but was quickly abandoned since the nuclear reactions were found to be not good for bomb-making. (more: http://youtu.be/bbyr7jZOllI?t=1m6s)

– Since the focus was on bombs and Uranium originally, the infrastructure of LWRs (light water reactors) quickly grew and stabilized, ignoring Thorium technologies such as LFTR (more: http://youtu.be/bbyr7jZOllI?t=12m1s – hear the Nixon tape – very damning evidence, and a real shame).

– This kind of reactor can’t “melt down” as it is already liquid.  It runs in the 700°C [1300 °F] range giving far superior thermodynamic efficiency.  High pressure is nowhere near the core, since a hot salt loop transfers the heat to the generators.

– The reactor is designed with a “salt plug” in its base, cooled by a fan.  If power is ever lost, the system fan would shut down (due to lost power), and the plug melts, draining the fuel into a storage container where fission stops.  The fuel would also cool and solidify.  If there were ever a breach in the reactor, material would drain into the same tank.  Even if the tank broke, the fuel would simply solidify on the floor.  Safety can be done completely passively, no worries about hoping systems will be online when needed.   (more:  http://youtu.be/enjc4arwH7U?t=3m30s)

– The reaction has a natural “negative feedback”, which means that if demand for power grows, the reactor will run faster, but if it falls, it will reduce its output.  It also will run slower as it gets too hot, so more heat does not make the reaction go out of control, it actually slows the reaction (due to expansion making fission less likely).

– The fuel is cheap (see Thorium above), and since there is no high pressure, huge thick walls and buildings are not necessary.  This lowers the space and cost requirements of a building.

– Any nuclear fuel generates Xenon gas while in a reactor.  This gas slows reactions and in the case of LWRs and other solid fueled reactors that we use today, it cracks and damages the fuel pellets.  Since LFTRs are liquid, it simply bubbles out of solution.  It can also be collected, and in a few months is no longer radioactive and can be sold.  This is also one reason the fuel in our current LWRs is only 0.5%-5% consumed, because if it were to be left in longer, the expansion from this would damage the fuel tubes inside of the reactor.

– LFTRs can make isotopes of materials we desperately need.  Mo-99 is needed by hospitals for radiation treatments, Pu238 is needed by NASA for space missions to the outer reaches of the solar system, and Bi213 for new targeted (Leukemia and Pancreas) cancer treatments. (more: http://www.youtube.com/watch?v=2at8C8YrX80)

– LFTRs can also burn radioactive “waste” we are currently storing, made from the LWR units of today.  We could actually reduce our radioactive waste using LFTRs and other Molten-Salt Reactors (MSRs) (more:  https://www.youtube.com/watch?v=i1fqB6p9pgM).

– China is already working on LFTR technology and stockpiling Thorium.  India is working on Thorium for solid fueled reactors, but will probably move to LFTR as a natural part of that research. (more: http://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor#Recent_developments)


Did you know?

– A typical coal burning plant emits far more radioactivity into the air than any nuclear plant.  Nuclear plants keep their fuels inside the building, but the smoke from coal contains all manner of poisonous materials (mercury, cadmium, etc) and several naturally radioactive ones such as Uranium and Thorium.  These materials are fairly safe as rocks, but as a breathable dust, not so much.

– Nuclear power is over 1,000,000 times more energy dense than burning fossil fuels.  The comparison is nuclear energy to that of a carbon-hydrogen bond. (more: https://www.youtube.com/watch?v=NG2jN–D2Es – See a visit to Arizona’s Palo Verde Energy Education Center outdoor exhibits)

– US current needs for energy burn a rail car of coal about every 1-3 seconds.  That’s about 100 tons per rail car.

– There have been far more deaths from coal mining than all nuclear power accidents combined. (more:  https://www.youtube.com/watch?v=4E2GTg7W7Rc – graphs at 2m:40s)




6 thoughts on “About LFTR – Liquid Flouride Thorium Reactors

  1. this is really interesting. i’d like to make an animated graphic of the core of a LFTR and put it on youtube and wikipedia. i wonder if you know of, or could create some simple sketches of the operation of an advanced LFTR core. i’d like to show how neutrons are produced by the U233 and thorium, etc, thanks steve

    • Welcome Martin from your site “hellosuckers.net”. As you know, I’ve been enjoying your investing site. Thanks for visiting.

      Your initial reaction to LFTR and thorium is very similar to my reaction when I first learned of it about 5 years ago. It seems unbelievable, but it is just advanced nuclear technology. I hope you have as much fun learning about it as I have.

      I’m happy to answer any questions, and as you can see, this site is designed to answer the kinds of questions one has when learning about this new technology.

      I created this site as an effort to get all the information for new people learning about the technology in one place. I’m looking forward to your comments and questions on other articles.

  2. Molten Salt Reactor designs easily remove fission products from the molten fuel; these block fission in Light Water Reactors, restricting LWR fuel use to <2% of the uranium. Gasses (especially Krypton, very strong fission blocker) bubble out of the fuel and are collected; other fission products are removed depending on the MSR design.

    Whether a MSR uses Th (converted to U233 inside the reactor) or "waste" fuel from LWR, 1000 kg in MSR makes over 1GW electricity. In LWR, 250,000 kg natural uranium to make 35,000 kg enriched uranium to make 1GW electricity. MSR (e.g. LFTR) takes 1/250 the fuel of LWR to produce the electricity. Depleted uranium is easily stored (very low radioactivity, casks work fine), so MSR leaves 1/35 the total radioactive waste. But with MSR, there are essentially no uranium or transuranic elements in the waste, so 830kg store for 10 years, and 170kg store for 350 years.

    "This kind of reactor can’t “melt down” as it is already liquid." — more importantly, the molten fuel self-regulates the fission reaction (higher temperature expands the salt, decreasing fuel density, which lowers fission) so the reactor can't get hot enough to melt the reactor vessel. (LWR operates ~ 350C, zirconium oxidizes ~500C releasing hydrogen — explosions at Fukushima were hydrogen — LWR reactor vessel materials can't handle the temperature the reactor can reach.)

    If the MSR reactor vessel breaks (e.g. projectiles or earthquake) the fuel salt leaks (no pressure to explode) and cools to solid — and most fission products are chemically bound to the salt, and are regularly removed, so minimal radiation to the environment. No water (that could carry hazardous materials away) is ever needed.

    "High pressure is nowhere near the core, since a hot salt loop transfers the heat to the generators." — MSR core is at atmospheric pressure, because the coolant doesn't boil (reactor temperature far below salt boiling point). The only pressure in the reactor is for the pumps — for heat transfer and for removing fission products.

    "quickly abandoned since the nuclear reactions were not good for bomb-making" — no, plutonium was important in nuclear power reactors not for making bombs, but for breeding more nuclear fuel. Uranium was scarce (we've since found much more), so breeding U238 to Pu239 (or Th to U33) was essential for a massive roll-out of nuclear power (that we never did). There was much more experience working with U/Pu than working with Th/U (due to the making Pu bombs) and Pu produces more neutrons than Th for breeding fuel — that's what the decision which to use was based on.

    Reactors (LWR) are too expensive and complex to use for making bomb material, and power for a city has to be interrupted as little as possible — plutonium for bombs is always made with simpler equipment — terrorists would make fuel for a nuclear bomb with a "graphite pile reactor" (literally a well-built pile of precisely-shaped graphite bricks with uranium in them). Steal from a nuclear reactor and you get a massive manhunt finding you; make your own in secret.

    "LWR (Light Water Reactor) in the US burns about 0.5% of the fuel put in it, the remaining 99.5% is disposed as unburned fuel as part of the radioactive waste. A LFTR on the other hand, running from Thorium could burn all 100% of the fuel" — LWR uses about 2% of the fuel. LFTR, and some other MSR designs, can use over 99% of the fuel, but no process is 100% efficient. This is from using molten fuel, whether uranium or plutonium or thorium. Uranium and all other actinides would be left in the reactor to fission or decay; there will be some left over when the reactor is decommissioned; there will be small amounts lost in chemical processing to remove fission products. Still MSR will leave a few kg long-term waste per GW electricity, where LWR leaves 35,000 kg, and coal leaves much much more. (Coal plants leave uranium and thorium in the ash piles, often open to the weather, plus all the non-radioactive toxic wastes — every coal plant is a worse toxic waste site than Fukushima, by far, just lacking hysterics.)


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