LFTR — Liquid Fluoride Thorium Reactor

What is a Liquid Fluoride Thorium Reactor? A type of Molten Salt Reactor, completely different reactor than we have been using (Light Water Reactor, LWR), with molten fuel cooled by stable salts. A LFTR can use inexpensive Thorium (would become uranium inside the reactor). Slightly different type of MSR can consume the uranium/plutonium waste from solid fueled reactors as fuel. MSRs make no long-term nuclear waste, and we know they work since we built and operated one — decades ago!
How LFTR Uses Thorium


  • LFTRs have no high pressure to contain (no water coolant), generate no combustible or explosive materials;
  • Freeze Plug melts in emergency, fuel drains to passive cooling tanks where fission is impossible;
  • Reactor materials won’t melt under normal or emergency conditions, radioactive materials stay contained. (Even if a bomb or projectile breaks the reactor vessel, it makes a spill that cools to solid, doesn’t interact with air or water, with most fission products chemically bonded to the salt);
  • LFTRs can passively cool even without electricity (never uses water);
  • Salt coolant can’t boil away (boiling point much higher than reactor temperature), so loss of coolant accidents are physically impossible.

Much More Economical

  • Ambient-pressure operation makes LFTRs easier and cost less to build (no pressure containment dome, no high-pressure pipes);
  • Operating cost is less since inherent safety means less complex systems;
  • Fuel cost is lower since thorium is a cheap, plentiful fuel; or eliminate LWR waste as fuel;
  • No expensive enrichment or fuel rod fabrication is required;
  • Total to develop LFTR technology and factory less than the $10-12 Billion cost of a Single new LWR; then 100MW LFTR would cost about $200 Million.

Much Less Nuclear Waste

LWR uses ~2% of the fuel, because fission products trapped in the fuel pellets block fission. The rest of the uranium is considered “waste”, to be stored for over 100,000 years. Well, that is waste only if we only use LWR. There are several types of nuclear reactor possible that can fission All that uranium, plutonium, and other transuranic elements. (God didn’t make useful uranium and defective uranium; it’s the reactor design that only uses ~2% of the fuel.)

MSR has molten fuel, no fuel pellets, no fuel rods. Some of the fission products, that block fission best, are gasses — in LWR they are carefully trapped in the pellets, in MSR they bubble right out of the fuel salt and are collected. Most other fission products are easily chemically separated from the circulating fuel salt. Most MSR designs, including LFTR, use over 99% of the fuel.

A LFTR’s waste is safe within 350 years. To produce 1 gigawatt electricity for a year, takes 800kg to 1000kg of thorium or uranium/plutonium waste. 83% of the fission byproducts are safe in 10 years, 17% (135 kg, 300 lbs) within 350 years, no uranium or plutonium left as waste. After that, radiation is below background radiation levels. (Compare to 250,000kg uranium to make 35,000kg enriched uranium for a solid-fueled reactor like LWR, for that same gigawatt-year electricity, all needing storage for 100,000+ years.)

No uranium, plutonium, or other long-term elements in LFTR waste, since they are simply left in the reactor until they either fission or decay to short-term waste. (Standard industrial processing inefficiency of 0.1% leaves 1kg uranium; we can do better than that, but still much less per gigawatt-year than the 5500 kg uranium left from an average USA coal plant!)

Most of the fission products are valuable for industrial use. After a few years, radioactive decay brings them below background radiation, ready for use.

Can Consume Nuclear Waste

Instead of thorium, a LFTR can use uranium-235 or plutonium waste, from LWR and other reactors. (Fast-spectrum MSR can use all isotopes of uranium, not just the 0.7% U235 in natural uranium — with all the safety and stability of MSR.) 800kg of nuclear waste would work in the same reactor instead of 800kg thorium, with about the same fission byproducts, same electrical output. Convert 800kg to be stored for 100,000+ years, to 135kg for 350 years and 665kg for 10 years. No “PUREX reprocessing” needed, simply extract the uranium and plutonium (including fission products) from the fuel rod, and put it in a MSR. (In a MSR designed to use a different salt than LFTR, the zirconium cladding of a fuel rod could even be used to make the salt coolant.)

Since no MSR uses water for cooling, there is no storage of water containing radioactive materials, and no concern of stored radioactive water leaking. (MSR can transfer heat to existing equipment such as steam generators, for example replacing the boiler at a coal plant, but doesn’t use water anywhere in the reactor.)

Easier Siting

Without needing a huge steam containment building (since there is no high pressure and no steam), LFTRs use a much smaller site. A LFTR containment building would protect the reactor from outside impacts, and have extra radiation shielding, but would be much smaller and less expensive than a LWR containment building. LFTRs can be safely built close to where there is electrical need (10MW to 2GW or more), avoiding transmission line power loss. No water source required. LFTRs could even be deployed for military field use or disaster relief.

Can Desalinate Water and Produce Vehicle Fuel

In addition to delivering carbon-free electricity, LFTRs high temperature output can desalinate water (which we need in some areas even more than electricity, and will need more as the world population grows).

LFTRs also can generate carbon-neutral vehicle fuels, from water and carbon dioxide (from the atmosphere or ocean or large CO2 sources such as coal plants). The high heat of a LFTR (over twice what a LWR can generate) can split CO2 and split water, so making gasoline will be affordable.

Carbon dioxide in the air enters the oceans, making acid. The acid is already killing plankton and other ocean life: the carbonic acid dissolves their “shells”. Researchers are exploring methods of using MSR heat to extract CO2 from solid materials containing a lot of CO2, store the carbon and release or use the oxygen, and then we could put those CO2-absorbing materials into the ocean to remove CO2 from the water. (Storing CO2 in a solid would work; storing compressed CO2 underground has a huge risk of leaks that would suffocate life on the surface.)

LFTRs are less expensive and more environmentally friendly than other sources of base-load power or grid power storage, needed to supplement wind and/or solar power.

National Roll-Out

The total cost of developing LFTR technology and building assembly line production (like assembly line production of aircraft, with better safety standards than is achievable with on-site construction, at much lower cost) will be much less than the $10-$12 Billion for a single new solid-fueled water-cooled reactor or single nuclear waste disposal plant. With sufficient R&D funding (around $1 billion), five years to commercialization is entirely realistic (including construction of factories, <$5 Billion), and another five years for a national roll-out is feasible. (Unfortunately, the U.S. Nuclear Regulatory Commission says they will start writing licensing and regulations in 30 years.)

Completely Different Reactor

There is very little LFTRs have in common with the solid fueled, water cooled reactors in use today. (Using thorium in a solid fueled, water cooled reactor, such as India is doing, does not give the safety and waste-reducing benefits of a molten fueled, salt cooled reactor.)

What is a Liquid Fluoride Thorium Reactor?

LFTR Uses a Liquid fuel, not Solid fuel

Thorium Converts to Uranium Inside the Reactor

No Chance of Nuclear Meltdown

LFTRs Do Not Need High Pressure Containment

No Water Needed for LFTRs, and no Loss of Coolant Accidents

No Long-Term Toxic Waste Storage

LFTRs Can Consume Nuclear Waste

Passive and Inherent Safety

Heat for Industrial Use

Worthless for Nuclear Weapons

More About Thorium

Useful LFTR Fission By-Products, for Industry and Medicine

Economics of LFTRs

Manufacturing LFTRs Easier than Other Reactors

Solving Technical Challenges in Building LFTRs

Downsides of LFTRs

How Might LFTRs Fail?

Additional Sources for LFTR Information

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30 thoughts on “LFTR — Liquid Fluoride Thorium Reactor”

  1. As concise and authoratative a presentation on the technology of the Thorium Molten Salt Reactor as I have ever seen. And I’ve seen many. Thanks. Who put it together?

    Franklin Tennessee

    1. Hi Robert, I put it together. I’m good at taking complex information and making it clear. George
      (I’ve added the FaceBook links, please “Like” this.)

  2. Alex Canara point me to you – very good stuff!
    I hope we can work together to promote Thorium.
    And I hope you can make it to the conference in Chicago May 31st.

    Feel free to ring me – I can be found at thoriumenergyalliance.com

    Hope to see you there!
    John Kutsch
    Executive Director
    Thorium Energy Alliance

  3. Hey There. I found your blog using msn. This is a really well written article. I will be sure to bookmark it and return to read more of Liquid Fluoride Thorium Reactor | Can't Melt Down, No Loss of Coolant Accidents, Consumes Nuclear Waste . Thanks for the post. I will definitely comeback.

    1. The main thing to keep in mind reading the IEER document (so biased I wouldn’t call it a fact sheet), is that thorium in a solid fuel reactor will have essentially the characteristics of other solid-fueled reactors like LWR; thorium in a molten salt reactor converts to U233, slightly less toxic fission products than U235, but very much the same characteristics as U235 in a molten fuel reactor. The IEER authors jumble statements that are accurate about solid fuel uranium, with statements accurate about solid fuel thorium, and think they are “proving” something about molten fuel thorium reactors (often in contradictory ways).

      Wikipedia “Molten Salt Reactor Experiment” has good actual results of the experiment, and problems they ran into and solved. The few they didn’t solve before funding was cut (for political reasons, not technical ones) have been solved since then.

      Main negative aspect of LFTR (or other molten salt reactors): the coal industry would be ruined (bad for them, very good for everyone else) and the LWR industry and NRC would make less money from making and storing tons of nuclear waste. 2nd negative is the legal hassles, including many laws are worded as if LWR were the only type of nuclear reactor possible (some law somewhere probably states “all nuclear reactors must have a steam containment building”, for example). 3rd is nobody has yet spelled out exactly how to deal with each element in the nuclear waste, so paranoid lawmakers will say “okay” (LFTR has dramatically less waste, and each element will be much easier to separate and store well, and scientists know how to store each element, but I haven’t heard of a detailed, clearly written nuclear waste document).

      Everything else “negative” I’ve heard about is actually just engineering design decisions, that engineers handle all the time, though non-engineers freak out about.

  4. What is your understanding of the fact that the two journals best positioned to provide a forum for the discussion of this transcendentally important issue, Physics Today and the Scientific American, have been irresponsibly silent?

    1. Have you written to their editors? Point them to this site, articles I’ve referenced, the Thorium Energy Alliance and Energy From Thorium sites? Can you write an article proposal for them?

  5. It’s a pity you don’t have a donate button! I’d without a doubt donate to this outstanding blog!
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  7. May I simply say what a relief to discover a person thwt really understands what they’re talking about online.

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  8. Excellent blog you have here but I was curious about if you
    knew of any community forums that cover the same topics talked about here?
    I’d really like to be a part of group where I can get advice from other
    knowledgeable people that share the same interest. If you have any suggestions,
    please let me know. Many thanks!

    1. People need to realize that the nauelcr industry is an exception to the rule of free enterprise. The kind of rights and freedoms that we take for granted in most areas of our lives don’t apply to nauelcr energy. So I totally agree with Rod (and Charles) and see this as an opportunity to say the obvious (to most readers) but it still needs repeating here: That the regulatory system needs changing or replacing or both. Then costs and schedule concerns will both improve enormously when fair practice of rules and regulations are observed.

  9. I have read several articles on “molten salt reactors” and find them very interesting. There seems to be very little down side to the technology. Are there any and If so what are they. The next question is what can we do to get these idiots in Washington out from under their windmills and away from their solar panels and do something positive like this. It seems to be economically feasible on KW/hour basis to not only build but operate. Michael

  10. Excellent blog here! Also your web site loads up very fast! What web host are you using? Can I get your affiliate link to your host? I wish my website loaded up as quickly as yours lol ebebadfabeck

  11. When I looked up thorium as an energy source in the past, there were indications that minimal shielding would be required, thereby enabling it’s use for automobiles and aircraft. Is there any truth to this? [Nope. Few inches of lead needed to stop gamma radiation, more thickness needed for less dense material; that is “minimal” only compared to the high-pressure safety systems needed for LWR. We won’t have LFTR-powered cars; we can have MSR provide heat to make gasoline from water + CO2. MSR could power aircraft, the 1st MSR was for that project, but the development of ICBMs removed the need. — George]

    1. We have nuclear-powered submarines. Aircraft have different requirements, especially throttling up/down; LWR, while similar to the reactors used in the first nuclear powered submarines, have fuel pellets that trap fission product gasses, especially xenon which is a good neutron absorber, stopping fission; LWR startup is a bit tricky. Molten Salt Reactors that have been built include the Aircraft Reactor Experiment, which was directly followed by the larger Molten Salt Reactor Experiment. (ICBMs eliminated the military need for a nuclear-powered bomber.)

      Don’t try making a nuclear-powered automobile. Even if you designed one that would work well technically (would be Big and Expensive), start building one and you’ll die, either from miss-handling radioactive material, or from men in black vans getting you, or from a nuclear-hysterical mob lynching you.

      After testing materials for high-temperature Molten Salt Reactors (1000C, instead of 650C with 1960s materials), making CO2-neutral vehicle fuels is simple chemistry, water plus carbon dioxide plus heat = gasoline. Then use the remaining heat to generate electricity. High-temperature reactor thermochemical power cycle for the production of gasoline, Fast Spectrum Molten Salt Reactor Options – Oak Ridge National Laboratories, 2011.

  12. OK glerner, Here you are 2 years after the first comments to this site. It has been a while.
    * What has been your progress (if any)?
    I’ve read about MSRs for at least 5 years now. Mostly beneficial material. I understand China is throwing R&D at this.
    *Is the US government still sitting on the side lines?
    * Why haven’t the entrepreneurs of the world (like Elon Musk, Bill Gates …etc) bought into this seemingly hugh beneficial tech?
    Just Wondering

    1. http://www.neimagazine.com/news/newsmolten-salt-reactors-enjoy-15-minutes-of-fame-4290903
      “The Alvin Weinberg Foundation is a London-based charity advocating for Gen IV reactors and thorium fuel, lists seven current international MSR projects: Ian Scott’s Moltex project in the UK, Elsa Merle-Lecotte’s EVOL project in France, the US Transatomic Power project, David LeBlanc’s Terrestrial Energy project in Canada, Kirk Sorensen’s Flibe Energy project in the USA, Motoyasu Kinoshita’s Fuji Reactor project in Japan, and Hongjie Xu’s MSR Project in China.”

      US Congress is still sitting on the side lines about Everything. I think politicians should be elected for their ability to evaluate many possible solutions, including the benefits, side effects, damage caused to people, financial costs, what could go wrong; pick the solution with the most good (for as many people as possible) and least bad (for the fewest people) — aka “moral decisions”, and their ability to have good solutions to tough problems be implemented. We have failed at electing even minimally competent people to US Congress. Note that moral decisions are not “pick something that someone said is good, and stick to it no matter what consequences, with no regard for any harm”.

      How about you ask Elon Musk, Bill Gates, etc? (Bill Gates is funding development of a solid fueled metal cooled fast reactor, TeraPower). Part of their decision might be shaped by the fact it is still an expensive project that could very well be shut down at any point by the (Light Water only) Nuclear Regulatory Commission, or Homeland Security, or the FBI or EPA or … at the command of the coal and oil companies. Extremely profitable company if you can ever build 10 reactors and not have them destroyed, what a coincidence, all at step 99 of 100.

      Perhaps those reactors being built would have to be secretly done at a time when coal and oil companies are kept busy with trains exploding every week, coal ash ponds sliding into rivers, oil wells blowing out, oil pipes leaking in residential areas, earthquakes in areas that never had them before but have them often since fracking, all in the news every week?

  13. Why are we not using this already? Seems to be the optimal way to supply the world with energy without any pollution to the environment. Its probably political decisions and the power (/money) of oil companies that have prevented this technology to be prioritised.

  14. I didn’t see any links to papers (merle-lucotte is a good starting point, she is at Grenoble) or websites for the EVOL project. Maybe I missed it. They seem to be the most advanced as far as published info.

  15. Dear Sir,

    I m a Business Developement Expert and I m writing from Istanbul, Turkey. I give consulting service to top Turkish Investors on Energy and investment. IF YOU ARE READY, I AM READY.. Just make sure that you can show us ( or built one on our expense! ) a prototype of a Thorium lftr reactor / generator / powerplant and you will be most wellcomed to be the partner of a government supported electric supply multi billion $ project at the soonest!!.
    I look forward for your positive respond at your earliest convenience.. Yours Truely, TT gsm: + 90 542 413 59 63

  16. I am doing research about nuclear reactors for Model UN and was interested in thorium reactors because I was told they would work really well, and let me tell you, this is by far the best article on thorium and the Liquid Fluoride Thorium Reactor by far! Thanks so much

  17. Great Site!

    Best of luck with your efforts to articulate a more optimistic vision of our short term options! For example: Building a Molten Salt reactor prototype to: 1) demonstrate commercial efficacy of a safe, abundant, carbon-free energy technology, 2) provide a non-proprietary path towards global prosperity, and 3) encourage building sustainable communities with people, robots and 3D printers.”

    If we can find a way to Go Viral with that message, legislators will respond immediately, regulatory hurdles will be removed, and human beings can finally unify behind a common vision of global prosperity!

  18. As suggested in one of your articles, I’d be interested in working with you or others on a documentary project to study readapting the currently closed Shorham nuclear facility on Long Is., NY as an MSR/LFTR R and D field site. My video interview with Dr. Stephen Boyd is on YouTube: http://www.youtube.com/watch?v=_ojJpwg6ZRU

    Please respond/contact me if you find the time, thanks

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No CO2, No High Pressure, No Loss of Coolant Accidents, No Long-Term Radioactive Waste