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
You can view this in these formats:
Need a web slide show, with matching all-slides presentation and blog? Has to be written very clearly? I can get that done for you. Contact Me.

10 thoughts on “LFTR — Liquid Fluoride Thorium Reactor

  1. Robert Orr Jr
    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. glerner Post author
      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. John Kutsch
    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. Inspirational Quotes
    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. glerner Post author
      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 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. Art Williams
    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. glerner Post author
      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?