LFTR vs SUFR

Advantages of a Liquid Fluoride Thorium Reactor (LFTR) compared with a conventional Solid Uranium Fueled Reactor (SUFR)

Environment

Process Heat

Waste

LFTR

Water

Cost

Safety

Electric Power

Hydrogen

Advantages of the Liquid Fluoride Thorium Reactor (LFTR) compared with the conventional, Solid Uranium Fueled Reactor (SUFR)

Environment

  • No greenhouse gasses as with SUFR– LFTRs, as with solid uranium fueled uranium reactors, produce no greenhouse gases.
  • Abundance of thorium – Thorium is 3.5 times more abundant than uranium and does not need to be enriched. That means less environmental pollution in its mining and processing.
  • No cooling water required– The lack of need for cooling water, both for LFTR operation and electric power generation, means less thermal pollution of large amounts of water.
  • More favorable distribution – LFTRs do not need to be large, isolated plants. They can be sited much closer to where they are needed.
  • Thorium needs no enrichment – Thorium fuel needs no enrichment. No “stranded” uranium from enrichment to deal with. Much less mining required; less stress on the environment.
  • 100% Fuel burn – 100% of thorium derived fuel is burned in a LFTR vs. 1 – 2% of enriched uranium burned in a SUFR. Far less chance of release of radioactive material in 300 years from LFTRs than in 10,000 years from SUFRs.
  • Less expansive grid pattern– LFTRs require far less long range grid because they can be located where they are needed
  • Inherent vs. engineered safety – The lack of core cooling water and molten salt fuel in a LFTR means the reactor is inherently safe. No possibility of explosion and spread of radioactive materials as in a SUFR.
  • Simpler licensing – Licensing is now an obstacle to LFTR development. The LFTR’s inherent safety and no need for cooling water should make licensing easier in the future. The faster we can deploy LFTRs, the better for the environment.
  • No meltdown threat – There can’t be a meltdown in a LFTR. This eliminates the possibility of radioactive release into the environment.
  • Less extensive mining – Unlike uranium, thorium mining need scarcely be done. It will most likely be a by-product of rare-earth mining. Also, one must mine 231 times as much uranium to get the same amount of usable fuel: far greater environmental impact from uranium.
  • Molten salt vs. solid fuel – This also has to do with cooling water or the lack thereof. There is no danger of molten salt fuel escaping into the environment.
  • No plutonium – LFTRs do not make plutonium, necessary for weapons production. This decreases the chance of proliferation. Unleashing atomic weapons is severely damaging to the environment.
  • Low-pressure means less material – The LFTR needs no massive pressure dome of steel and concrete – far less material to mine and manufacture.
  • Less waste to process – LFTR fuel is continuously processed to remove fission products. There is only 1 – 2% as much material to remove than from a SUFR. The environment is safer if there is far less radioactive material needing far less time to stabilize.
  • Less radiation – IF we consider radioactive fallout from the air or radioactive material released into the ocean environmental hazards, the LFTR simply will not produce any.
  • More siting flexibility – The LFTR can be tucked in just about anywhere. It has a much smaller footprint than the SUFR because of inherent safety and no need for cooling water. There is less environmental impact.
  • Less spent fuel – Spent fuel from a LFTR (fission products only) is a far less environmental threat than from a SUFR (fission products plus transuranics plus unburned uranium) because the SUFR spent fuel is dangerously radioactive for thousands of years. How do we know that it can be successfully managed that long? Fission products from the LFTR are nowhere near as plentiful, radioactive, or long-lasting.
  • Little spent uranium – This is the uranium left over after enrichment for SUFRs – more than 85% of what was mined in the first place. It has to be stored and supervised to avoid becoming an environmental hazard. In addition, uranium tailings from mining are also environmentally unfriendly. LFTRs need little enriched uranium for start-up only.

Process Heat

  • No cooling water required – The LFTR does not require cooling water, so it can run much hotter than a SUFR. This means that LFTR process heat is much more valuable.
  • More available heat applications – LFTRs can be much more easily and widely distributed than SUFRs, so they are more available for process heat applications.
  • Molten salt vs. solid fuel – The liquid fuel form in the LFTR is central to all its advantages, including process heat. Thorium adapts beautifully to the molten salt concept. Molten salt is superior to water for heat transfer.
  • Low pressure operation – Pressure, cooling water, siting, and distribution are all tied together. If the reactor core does not require water, there is no pressure problem, so LFTRs can be much more widely distributed.
  • More flexible siting – Siting is much easier for a LFTR, so process heat is more accessible close to where it is needed.

Waste

  • Abundance of thorium – Thorium is 3.5 times more abundant than uranium. Also, mined thorium is 100% usable compared with uranium which has only 0.72% fissionable 235U.
  • No cooling-water required – Why waste cooling water in a conventional SUFR reactor when it is not required for core cooling in a LFTR and is optional for electric power generation when using a LFTR to produce the necessary heat?
  • Thorium needs no enrichment – The uranium enrichment process leaves more than 80% of mined uranium “stranded” whereas all mined thorium is usable.
  • 100% Fuel burn –All the thorium- produced fuel is “burned” in a LFTR; Over 98% of the fuel in a SUFR winds up as waste.
  • Simpler licensing – Licensing should be much simpler because LFTR waste is neither as dangerous nor as long-lived as waste from a SUFR. No requirement for a pressure vessel or for cooling water should also simplify licensing. Also, there is nowhere near the mining waste from thorium as from uranium.
  • Mining less extensive – Uranium mining leaves either tailings or waste water (or both). Thorium need not be mined at all if it can be derived as a tailings produced from rare-earth mining.
  • Molten salt vs. solid Fuel – This is a fundamental difference that is critical to all arguments. The molten salt reactor using thorium produces far less waste than SUFRs. It is also the means of low-pressure operation.
  • No plutonium – Plutonium survives as part of the waste stream from SUFRs; LFTRs make negligible amounts of plutonium.
  • Simplified processing – No reprocessing SUFR waste is performed in the U.S. today. Processing of fuel to remove fission products would be advantageous in a LFTR. The volume from a LFTR would be less than 1/30th as much as from a SUFR.
  • Lower radioactivity – Radiation from LFTR waste would be about one ten-thousandth as much as from a SUFR because there are virtually no transuranics produced in a LFTR.
  • No shutdown for refueling – Refueling is a laborious, time consuming, expensive process in a SUFR, requiring shutdowns of up to a month. Waste is recovered from a SUFR during refueling. Refueling the LFTR is continuous and easily accomplished without shutdown.
  • Less spent fuel – The spent fuel from a LFTR consists of only the fission products of the reaction; the spent fuel from a SUFR contains the fission products, mostly unused U238, plutonium, and transuranic elements generated from the U238.
  • Little spent uranium – Spent uranium is the largest waste stream from uranium mining and enrichment for use in a SUFR; it exists only from generating the LFTR start-up fuel.

Water

  • No Cooling-water required – Water is becoming a scarce and more valuable resource, and the LFTR, unlike the SUFR, does not need water either for core cooling or for electric power generation. Furthermore, the LFTR provides inexpensive heat for water purification and transport.
  • Inherent vs. engineered safety – No requirement for cooling water is one reason that the LFTR is inherently safe vs. the SUFR having to be engineered safe.
  • No Meltdown threat – Meltdown is a non-event for a LFTR. Its fuel load is already molten at a high temperature in a safe configuration.
  • Molten salt vs. solid fuel – The SUFR requires water for cooling; the LFTR does not. This leads to safer, more efficient, useful operation.
  • Low-pressure operation – LFTR operates at atmospheric pressure because there is no water associated with the core. The only place where there is high pressure is in electric power generation, where there is no contact with the radioactive fuel load.

Cost

  • Abundance of thorium – There is much less cost to obtaining usable thorium than fissionable uranium due to its abundance. Thorium can be obtained as a by-product of rare-earth mining.
  • No Cooling-water required – No need for cooling water means no need for a massive pressure vessel – a huge saving. Also, there is no need for supplies of cooling water stored in case of pump failure, another great saving.
  • More favorable distribution – Amenability to wider distribution of LFTRs means smaller plants with less build time and much lower capital cost.
  • Thorium needs no enrichment – Thorium as a waste by-product of rare earth mining is really cheap; enriched uranium costs about the same as platinum, and you need 30 times as much.
  • Smaller footprint – The LFTR’s smaller footprint means less cost for land, less cost for security, less cost for all facilities.
  • 100% fuel burn – The fact that you burn up 100% of cheap thorium but only 1% to 2% of expensive uranium, makes for a huge saving.
  • Secure fuel transport – Security measures for transporting non-fissile thorium are nonexistent vs. security measures for enriched uranium.
  • No major grid upgrades required – Grid requirements for distributed LFTRs are a fraction of those for large, isolated SUFRs. No huge grid up-grades are required.
  • Inherent vs. engineered safety – The inherent safety of a LFTR vs. the requirement for engineered safety in a SUFR leads to huge savings.
  • Simpler licensing – Licensing costs should be much less for LFTRs because of their inherent safety. Designs could be licensed rather than facilities.
  • No meltdown threat – Meltdown is a constant danger in a SUFR and must be prepared for at great expense. A molten salt is the normal state for a LFTR and has great advantages.
  • Mining less extensive – 250 times as much uranium must be mined to produce the same amount of power as thorium. It is quite possible that direct thorium mining can be avoided altogether.
  • Molten salt vs. solid fuel – This advantage of a LFTR over SUFR is central to all our arguments: no cooling water, no pressure dome, better heat transfer, higher process heat temperatures, etc., and all lead to lower costs.
  • No plutonium – Unprocessed waste from a SUFR contains plutonium, a weapons material, that must be controlled for centuries. The LFTR does not produce plutonium.
  • No pressure vessels required – There is no need for pressure vessels for LFTRs as there is for SUFRs; a huge cost saving.
  • Less waste processing – The only reason processing (reprocessing) is not a cost for SUFRs is because it is forbidden by law (in the U.S.). That cost then becomes maintaining control of waste from these uranium reactors for ten thousands years. Processing of LFTR waste is necessary, but some of the products are valuable, and there is only 2% as much material to process for the same amount of power produced.
  • Lower radiation – LFTRs produce much less radioactivity in their waste products than SUFRs. Some of the 238U in the fuel rods is converted to transuranics that are very radioactive and very long- lived. LFTRs do not produce transuranics.
  • No shutdown for refueling – Fueling for a LFTR is a continuous bleed of thorium tetrafluoride into the blanket while the reactor continues to operate. Refueling of the SUFR requires shutdown, followed by complex removal, replacement, and rearrangement of fuel rods – an expensive, time consuming process.
  • More flexible siting – The LFTR can be sited in so many more places than a conventional reactor that costs are avoided by not needing large isolation zones.
  • Less spent fuel – 100% of thorium fuel introduced to LFTRS is “burned” leaving only the fission products vs. enriched uranium fuel introduced to SUFRs that is removed after only 1% to 2% is “burned”.
  • Almost no spent uranium

Safety

  • No cooling-water required – That the LFTR needs no core cooling water is pivotal to its inherent safety. It eliminates the need for a pressure dome and the possibility of steam or hydrogen explosions, as in a SUFR.
  • No diversion to weaponry – Diversion of fuel to weaponry is extremely difficult with the LFTR. Also, the LFTRs can be designed with a very tight neutron economy. Any significant diversion of fissionable material would cause the reactor to stop operating.
  • No transport of fissionable material – Once the reactor has been started with its initial load of fissionable material, no fissionable material need be transported either to or from the LFTR.
  • Inherent vs. engineered safety – The design and physical characteristics of the LFTR means that it is inherently safe, whereas the SUFR must be designed safer.
  • Simpler licensing – Licensing should be easier and cheaper due to the inherent safety features of the LFTR.
  • Molten salt vs. solid fuel – One could use thorium in a solid-fuel reactor, but it would not make any sense to use it in a system requiring cooling water that would radically reduce safety.
  • No plutonium – Plutonium is a threat to safety because of its use for weapons. The LFTR does not make plutonium.
  • Low-pressure operation – None of the fuel processing circuits or the reactor core in a LFTR are under significant pressure. Thus, any break in the system will not disperse radioactive materials into the environment.
  • Simplified processing – Processing of the fission products from the LFTR is simplified by the small amount of material and its radically less radioactivity than from a SUFR.
  • Lower radioactivity – Safety concerns are diminished by the LFTR’s small amount of fission products, lack of transuranics, and much smaller amounts and shorter times of storage.
  • More compact siting – Siting is much less restricted because of the safety and size characteristics of the LFTR.
  • Less spent fuel – Spent fuel from the LFTR is safer by its far lower volume and far less radioactivity, and much shorter storage time.

Electric Powery

  • No cooling-water required – Absence of need for cooling water is a huge advantage for dry areas like Wyoming.
  • More favorable grid distribution – LFTRs can be more widely distributed than SUMRs, so there need be less grid. Base and peak load would mostly be locally produced, so the current grid would be adequate for load balancing.
  • Efficiency through higher temperatures – Higher temperatures of LFTRs will markedly improve efficiency of electric power generation, which follows from the second law of thermodynamics.
    Electric power continued
  • Smaller footprint – The smaller footprint of the LFTR means that it can be placed nearer to sites of power need.
  • No plutonium – LFTRs used for power generation will not make plutonium.
  • No shutdown for refueling – A LFTR is refueled continuously, without shutdown; Refueling of a SUFR can take up to a month and must be done about every two years. There should be little need to shut down a LFTR.
  • Simpler siting – The simpler, smaller siting requirements will make LFTRs ever more valuable for power generation.

Hydrogen

  • Produced hydrogen less expensive – Using LFTR process heat to produce hydrogen from water should be much less expensive than from other heat sources, such as SUFR.
  • More flexible siting – The inherent safety characteristic of the LFTR would allow siting close to locations where LFTR process heat would be used to make hydrogen.
  • Liquid vs. solid fuel – The higher operating temperatures and lower cost of LFTRs vs. SUFRs make LFTRs ideal for low-cost hydrogen production.