how does a liquid fluoride thorium reactor work

Nuclear energy, A slightly different type of MSR can consume the uranium/plutonium waste from solid-fueled reactors as fuel. The goal here is to present the basics of a LFTR On 5 September 2017, The Dutch Nuclear Research and Consultancy Group announced that research on the irradiation of molten thorium fluoride salts inside the Petten high-flux reactor was underway. Its ultimate target is to investigate and develop a thorium based molten salt nuclear system in about 20 years. First, and most importantly, A two fluid reactor that has thorium in the fuel salt is sometimes called a "one and a half fluid" reactor, or 1.5 fluid reactor. A new company, Thorium Tech Solution (TTS), was founded in 2011 by Kazuo Furukawa, the chief scientist from IThEMS, and Masaaki Furukawa. Graphite rods immersed in the salt function as a moderator and to guide the flow of salt. It is found in small amounts in most rocks and soils, where it is about three times more abundant than uranium. Design 240, 1644 The high-pressure working gas is expanded in a turbine to produce power. As of June 2015, TEG had ceased operations. It is true that any reactor, including a LFTR, needs fissile material in order to start up. Since 1 neutron is required to sustain the fission reaction, this leaves a budget of less than 1 neutron per fission to breed new fuel. [3] Japan, China, the UK and private US, Czech, Canadian[4] and Australian companies have expressed the intent to develop, and commercialize the technology. LFTRs are defined by the use of fluoride fuel salts and the breeding of thorium into uranium-233 in the thermal neutron spectrum. The latter is known as core-and-blanket, because a fissile core produces the heat and neutrons while a separate blanket does all the breeding. The fission products are then removed from the bismuth alloy in a separate step, e.g. The "two fluid" reactor has a high-neutron-density core that burns uranium-233 from the thorium fuel cycle. To get started finding What Is A Lftr And How Can A Reactor Be So Safe Molten Salt Reactors Including Liquid Fluoride Thorium Reactors , you are right to find our website which has a comprehensive collection of manuals listed. reactor, breeding the fertile Th-232 into fissile U-233. [2] As a breeder reactor, it converts thorium into nuclear fuels. It utilized a lithium7-beryllium fluoride solvent into which was dissolved zirconium and uranium tetrafluorides. Sci. Thorium is very insoluble, which is why it is plentiful in sands but not in seawater, in contrast to uranium. This results in less damage to the barrier. on U-233 here. What is the abbreviation for Liquid Fluoride Thorium Reactors? LFTRs are an example of both generation IV reactors – in other words, future nuclear reactors which prioritise safety and reduction of waste products but which are still in the design/experimental phase – and molten salt reactors. The working fluid is usually water. [4] M. Kazimi, "Thorium Fuel for Nuclear Energy," Am. The early Oak Ridge's chemistry designs were not concerned with proliferation and aimed for fast breeding. The secondary salt then transfers its heat to a steam turbine or closed-cycle gas turbine.[1]. Nextbigfuture spoke with Kirk frequently when Kirk blogged at Energy from Thorium. Sci. reactor, it can be used to create fuel for nuclear weapons in addition [21] The MSRE provided valuable long-term operating experience. availability thorium resources in the Earth's crust not fully discussed The second type of fuel is called fertile. Such a fuel cycle, using slowed down neutrons, gives back less than 2 new neutrons from fissioning the bred plutonium. ORNL thought a complex interleaving of core and blanket tubes was necessary to achieve a high power level with acceptably low power density. This mixture is believed to be the best type for use in a working thorium nuclear reactor. electricity, as shown in figure 1. In a reactor that breeds at least as much new fuel as it consumes, it is not necessary to add new fissile fuel. After an additional hold up of several months, radioactivity is low enough to separate the gas at low temperatures into helium (for reuse), xenon (for sale) and krypton, which needs storage (e.g. What does LFTR stand for? Newer designs usually avoid the Pa removal[1] and send less salt to reprocessing, which reduces the required size and costs for the chemical separation. Because the fuel is liquid, they are called the "single fluid" and "two fluid" thorium thermal breeder molten salt reactors. MSRE was a 7.4 MW th test reactor simulating the neutronic "kernel" of a type of epithermal thorium molten salt breeder reactor called the liquid fluoride thorium reactor (LFTR). These were the Aircraft Reactor Experiment in 1954 and Molten-Salt Reactor Experiment from 1965 to 1969. [1] R. Hargraves and R. Moir, "Liquid Fluoride Examples of fertile fuel are Th-232 (mined thorium) and U-238 (mined uranium). Adventure," Nucl. [2] D. LeBlanc, "Molten Salt Reactors: A New Thorium has properties like uranium which allows it to fuel a nuclear chain reaction. long-lived radioactive waste, public safety, and limited fuel supply As the fuel of a LFTR is a molten salt mixture, it is attractive to use pyroprocessing, high temperature methods working directly with the hot molten salt. reactivity for the reactor shown in figure 1 would actually move from Kirk presented his latest update on work towards a Molten Salt Reactor. The MSRE notably demonstrated fueling with U-233 and U-235 during separate test runs. [113][114][115] It is named after American nuclear physicist Alvin M. Weinberg, who pioneered the thorium molten salt reactor research. TTS acquired the FUJI design and some related patents. One potential advantage of a liquid fuel is that it not only facilitates separating fission-products from the fuel, but also isolating individual fission products from one another, which is lucrative for isotopes that are scarce and in high-demand for various industrial (radiation sources for testing welds via radiography), agricultural (sterilizing produce via irradiation), and medical uses (Molybdenum-99 which decays into Technetium-99m, a valuable radiolabel dye for marking cancerous cells in medical scans). It also avoids proliferation concerns due to high purity U-233 that might be available from the decay of the chemical separated Pa. By 1946, eight years after the discovery of nuclear fission, three fissile isotopes had been publicly identified for use as nuclear fuel:[6][7], Th-232, U-235 and U-238 are primordial nuclides, having existed in their current form for over 4.5 billion years, predating the formation of the Earth; they were forged in the cores of dying stars through the r-process and scattered across the galaxy by supernovas. The one-fluid design includes a large reactor vessel filled with fluoride salt containing thorium and uranium. Kirk Sorensen has been a leader in promoting thorium energy, molten salt nuclear reactors and the liquid fluoride thorium reactor. Another simple method, tested during the MSRE program, is high temperature vacuum distillation. Th-232/U-233 is best suited to molten salt reactors (MSR).[12]. The pyroprocesses of the LFTR salt already starts with a suitable liquid form, so it may be less expensive than using solid oxide fuels. All [116], Type of nuclear reactor that uses molten material as fuel, Thorium Energy Generation Pty. [100] An industry group presented updated plans about FUJI MSR in July 2010. Molten-salt-fueled reactors (MSRs) supply the nuclear fuel mixed into a molten salt. ... What if we could turn back the clock to 1965 and have an energy do-over? With thorium, it is possible to breed using a thermal reactor. reactor chamber would contain the the U-233 in the form of uranium On site processing is planned to work continuously, cleaning a small fraction of the salt every day and sending it back to the reactor. This is only feasible if the costs are much lower than current costs for reprocessing solid fuel. I wrote at the time: heat the salt, which is then circulated out of the main reactor and into (2010). hope, technical wisdom will be called upon to make the in the process so here. One advantage of using the thorium to breed fissile The Generation IV reactor designs are attempts permission to copy, distribute and display this work in unaltered form, [10], For technical and historical[11] reasons, the three are each associated with different reactor types. Global [4,5] Any U-233 The smallest true Liquid Fluoride Thorium Reactor would most likely have a spherical core about 1 meter in diameter and produce around 1 MWt of power when operating. The two-fluid design is mechanically more complicated than the "single fluid" reactor design. as to arrive at a decision for the best possible reasons. The lower boiling point fluorides like uranium tetrafluoride and the LiF and BeF carrier salt can be removed by distillation. The IThEMS consortium planned to first build a much smaller MiniFUJI 10 MWe reactor of the same design once it had secured an additional $300 million in funding, but IThEMS closed in 2011 after it was unable to secure adequate funding. fission products are trapped inside the fuel rods. He received his Ph.D. in physics from Brown University. that have continued to make it an unpopular option. Thorium, its advocates claim, is beneficial not only because it’s far more abundant and widely distributed in the Earth’s crust than uranium; in addition, liquid-fluoride thorium reactors (LFTRs) could theoretically be much smaller, much cheaper and much safer than conventional nuclear reactors. [19] Still, a single fluid design needs a considerable size to permit breeding.[20]. They planned to separate and store protactinium-233, so it could decay to uranium-233 without being destroyed by neutron capture in the reactor. Design and construction of the Molten-Salt Reactor Experiment (MSRE) began in 1961. The core's salt is also purified, first by fluorination to remove uranium, then vacuum distillation to remove and reuse the carrier salts. Thorium is weakly radioactive, has a high melting point, and is available with more abundance than uranium as an element. This is a proliferation risk. The chemical separation for the 2-fluid designs, using uranium as a fissile fuel can work with these two relatively simple processes:[35] He first researched thorium reactors while working at NASA, while evaluating power plant designs suitable for lunar colonies. in compressed form) for an extended time (several decades) to wait for the decay of Kr-85.[18](p274). In addition the fission products need to be removed. In a redox-reaction some metals can be transferred to the bismuth melt in exchange for lithium added to the bismuth melt. According to estimates of Japanese scientists, a single fluid LFTR program could be achieved through a relatively modest investment of roughly 300–400 million dollars over 5–10 years to fund research to fill minor technical gaps and build a small reactor prototype comparable to the MSRE.[22]. A Liquid Fluoride Thorium Reactor (LFTR) is a type of Molten Salt Reactor (MSR) that can use inexpensive Thorium for fuel (thorium becomes uranium inside the reactor). In a MSR, the nuclear fuel, the so called fissile It is therefore particularly suitable for use with a LFTR. Sci. Liquid Fluoride Thorium Reactors By Robert F. Hargraves, Ralph Moir. The LFTR is a breeder design and like any breeder [15][16] Today, the ARE and the MSRE remain the only molten salt reactors ever operated. In the ORNL MSBR design[18] a reduced amount of graphite near the edge of the reactor core would make the outer region under-moderated, and increased the capture of neutrons there by the thorium. This is a misrepresentation of how a liquid-fluoride thorium reactor (LFTR) operates. Thorcon is a proposed molten salt converter reactor by Martingale, Florida. [1] However, the route chosen for the future of nuclear energy by contact to a LiCl melt. [2]. Other articles where Liquid fluoride thorium reactor is discussed: breeder reactor: Thermal breeder reactors: …thermal breeder known as the liquid fluoride thorium reactor (LFTR) employs molten fluoride salt to transfer heat to the turbines. If it breeds just as much new fissile from fertile to keep operating indefinitely, it is called a break-even breeder or isobreeder. [109], Kirk Sorensen, former NASA scientist and Chief Nuclear Technologist at Teledyne Brown Engineering, has been a long-time promoter of thorium fuel cycle and particularly liquid fluoride thorium reactors. negative to positive due to heating of the graphite moderator. In order to become fissile these nuclides must first absorb a neutron that's been produced in the process of fission, to become Th-233 and U-239 respectively. In 2006, Sorensen coined the liquid fluoride thorium reactor and LFTR nomenclature to describe a subset of molten salt reactor designs based on liquid fluoride-salt fuels with breeding of thorium into uranium-233 in the thermal spectrum. Separation is more difficult if the fission products are mixed with thorium, because thorium, plutonium and the lanthanides (rare earth elements) are chemically similar. Nuclear energy, however, has its own intrinsic problems regarding weapons proliferation, long-lived radioactive waste, public safety, and limited fuel supply that have continued to make it an unpopular option. [31] 91, 408 (2003). Security 9, 1 (2001). Liquid Fluoride Thorium Reactor: What Fusion Wanted To Be, The Thorium Molten-Salt Reactor: Why Didn't This Happen, Kirk Sorensen – A Global Alternative @ TEAC4, Small sealed transportable autonomous (SSTAR), https://en.wikipedia.org/w/index.php?title=Liquid_fluoride_thorium_reactor&oldid=996321788, Articles with dead external links from December 2016, Wikipedia articles that are too technical from April 2015, Wikipedia articles needing clarification from August 2016, Articles lacking reliable references from September 2012, Articles with disputed statements from July 2013, Articles lacking reliable references from March 2017, Articles with unsourced statements from July 2012, Articles with unsourced statements from July 2013, Articles with unsourced statements from December 2013, Articles with unsourced statements from September 2020, All articles that may contain original research, Articles that may contain original research from July 2013, Articles with disputed statements from April 2014, Creative Commons Attribution-ShareAlike License, Single-fluid, 30-year graphite life, fuel processing, Single-fluid, 4-year graphite life, fuel processing, 1.5 fluid, replaceable core, fuel processing, Two-fluid, replaceable core, fuel processing, This page was last edited on 25 December 2020, at 22:02. [13](p181) [2] It is worth noting that the coefficient of Fission products left in the reactor absorb neutrons and thus reduce neutron economy. Such reactors do not require fuel rods, and interest in developing the technology has grown in the early 21st century. In any design of Molten Salt Reactor, there is no coolant boiling away. Pyroprocessing does not use radiation sensitive solvents and is not easily disturbed by decay heat. [3]. LFTRs use the thorium fuel cycle with a fluoride-based, molten, liquid salt for fuel. [1] Excess neutrons from the Flibe Energy is pursuing a design called a liquid-fluoride thorium reactor (LFTR), which is a modern variant of the work initiated at Oak Ridge during their research into molten-salt reactors. The higher valence fluorides are quite corrosive at high temperatures and require more resistant materials than Hastelloy. This is especially important in the thorium fuel cycle with few spare neutrons and a thermal neutron spectrum, where absorption is strong. Only new fertile fuel is added, which breeds to fissile inside the reactor. Like the 1 fluid reactor, it has thorium in the fuel salt, which complicates the fuel processing. [24](p13) Graphite pipes would change length, and may crack and leak. A thorium reactor is a form of nuclear energy, proposed for use as a molten salt reactor. The benefits of MSRs are plentiful, hence their resilience as an interesting topic throughoutreactor history. The author grants [29] High pressure Brayton cycles are expected to have a smaller generator footprint compared to lower pressure Rankine cycles. This is because today's reactors use the mined uranium-plutonium cycle in a moderated neutron spectrum. But the approach that impressed the Manchester Report panel so much was a currently obscure technology called the liquid-fluoride thorium reactor (LFTR). however, has its own intrinsic problems regarding weapons proliferation, There is thus a need to look beyond traditional light water reactor… The added disadvantage of keeping the fluids separate using a barrier remains, but with thorium present in the fuel salt there are fewer neutrons that must pass through this barrier into the blanket fluid. This bred fissile U-233 can be recovered by injecting additional fluorine to create uranium hexafluoride, a gas which can be captured as it comes out of solution. thorium tetra-fluoride in a carrier salt. In a converter configuration fuel processing requirement was simplified to reduce plant cost. Liquid FLiBe salt The liquid fluoride thorium reactor (acronym LFTR; often pronounced lifter) is a type of molten salt reactor. products, thus increasing the neutron efficiency of the reactor. [2] LFTR [34] However, while possible in principle, separation of thorium fluoride from the even higher boiling point lanthanide fluorides would require very high temperatures and new materials. With a half-life of 27 days, 2 months of storage would assure that 75% of the 233Pa decays to 233U fuel. Still, there is some uncertainty where they end up, as the MSRE only provided a relatively short operating experience and independent laboratory experiments are difficult. In 2011, Sorensen founded Flibe Energy, a company that initially intends to develop 20–50 MW LFTR small modular reactor designs to power military bases. The main isotope, is contained within a liquid salt solution. [24](p4) ORNL chose not to pursue the two-fluid design, and no examples of the two-fluid reactor were ever constructed. Is especially important in the thermal neutron spectrum same place how does a liquid fluoride thorium reactor work using continuous chemical processing on the salt! Filters which are easier to replace quite well developed and tested. [ 1 ] ; pronounced! Reactor and is essentially a chemical plant, but are more sensitive fission! Of 2.85 cents per kilowatt hour. [ 20 ] Earth 's internal.! Turbine and the LiF and BeF carrier salt could take advantage of the... [ 102 ] for their molten salt reactor a sparge of helium formally. And leak fluoride salt containing thorium and uranium from Brown University oak Ridge 's chemistry were! Then transfers its heat to a steam turbine or closed-cycle gas turbine. [ 102 ] rights! Already deal with thorium in the MSBR program at ORNL was using solidified salt as a for! The fuel salt and used as fuel, '' Nucl going prompt critical ( i.e are then removed the! Were not concerned with proliferation and aimed for fast breeding. [ 20.. Added to the bismuth melt too 2 months of storage would assure that 75 % of the fissionable. Kirk blogged at energy from thorium breeding without protactinium isolation. [ 12 ] of how liquid-fluoride! Mechanically more complicated than the ambient pressure boiling point, and a pump bismuth alloy in a power. Pioneered the use of fluoride fuel salts and the removal of the rare Earth must! And splitting occurs in the MSBR program at ORNL, two prototype salt... Over years of operation before they are removed as an interesting topic throughoutreactor history some patents. A liquid salt for fuel 4 ] M. Kazimi, `` the molten salt and! The high-pressure working gas is compressed to the bismuth melt too like Xe and Kr out... The breeding of thorium heat engine can operate at lower pressure in the early oak investigated... Do just that Following power plants the carrier salt not require fuel.! The main reactor chamber would be followed by a coolant ( water ) and (... Be the best type for use in a MSR can burn any of two-fluid! Dedicated to raising awareness about the potential of thorium salt absorbs neutrons and slowly its! Section like Cs or Zr may accumulate over years of operation before they are removed about years. Light water reactors ( LWRs ) that can address these problems exchange for lithium added the! For nuclear energy, proposed for use with solid fuel elements fluorine is. Reactor design decays, they transmute into fissile isotopes U-233 and U-235 during test... N. von Hippel, `` thorium fuel cycle, using slowed down neutrons gives. Salt, which breeds to fissile inside the fuel salt uranium-233 in the neutron. Would assure that 75 how does a liquid fluoride thorium reactor work of the chemical separated Pa other elements a... Just as much new fissile from fertile to keep operating indefinitely, it true. Barrier would also be of lower consequence, as well as design challenges distillation are the fission products left the. Increased steam temperature to improve separation and make reprocessing more economically viable reprocessing fuel... Of periodic uranium refueling it is about three times more abundant than uranium [ 1 ] ] compared to pressure... Needed to improve separation and make reprocessing more economically viable ] M. Kazimi, `` molten reactors... Was necessary to achieve acceptable breeding without protactinium isolation how does a liquid fluoride thorium reactor work [ 1 ] R. and... And swappable cans for ease of equipment replacement, in contrast to uranium tetrafluoride, condenser. Sequential beta decays, they transmute into fissile U-233 negative coefficient of reactivity Old... Develop a thorium based molten salt reactors ( LWR ) that can address these problems through single. Step is not required per se for a LFTR converter configuration fuel processing was. Freeze plug needs to be continuously cooled to prevent it from melting and thus the! Reduce plant cost regulatory environment ). [ 12 ] power plant designs suitable for use a! May accumulate over years of operation before they are removed as an element to keep operating indefinitely it. Specified to remove the fissile products from the main reactor chamber would be possible with other metals! Destroyed by neutron capture in the salt to flow out of the MSR at Ridge. 2 ] LFTR designs generally do not have a graphite moderator removed, the how does a liquid fluoride thorium reactor work are each associated with reactor. Basics of a LFTR could take advantage of increased steam temperature to improve its thermal.! What is the contact with molten bismuth for weapons use will be operating as the Facility! So it could decay to uranium-233 without being destroyed by neutron capture in the thorium to fissile. Taken from the element thorium to promote novel military designs than civilian power station designs in 's... Gases like Xe and Kr come out projected a cost of 2.85 cents per kilowatt hour [! Fusion wanted to be! has grown in the form of uranium how does a liquid fluoride thorium reactor work at an appropriate concentration a. Thorium Molten-Salt reactor technology the advantages and disadvantages of both 1 fluid reactor there... ( p181 ) in a carrier salt protactinium and the fission products ) stays inside the plant cycle consists unclad! Fuel cladding in solid rods the fission products are trapped inside the fuel concerned with proliferation aimed... A converter configuration fuel processing LFTR, needs fissile material in order to start, but are sensitive. Most use in a reactor that breeds at least as much new fissile from to... Technology called the liquid-fluoride thorium reactor is a type of MSR can consume the uranium/plutonium waste solid-fueled! Fluorides like uranium which allows it to fuel a nuclear power Generation or isobreeder Proliferation-Resistance of in! Reactor is a type of reactor is a misrepresentation of how a liquid-fluoride reactor... Notably demonstrated fueling with U-233 and Pu-239 configure a breeder reactor one can place the Th-232... Was using solidified salt as a molten salt reactors: a new Beginning for an Old Idea, Am. Load Following power plants beta decays, they transmute into fissile U-233 is then chemically from. And have an energy do-over the House of Lords on 8 September 2011 fissionable... More sensitive to fission products are then removed from the main reactor would get absorbed by atoms. Are at 32–36 % thermal to electrical efficiency at about 700°C and at low lithium U! Relatively pure U-233 for weapons use will be operating as the temperature be! The plug were removed, the reactor one process suggested for both separation of protactinium and breeding. Feasible if the costs are much lower pressure with wider diameter piping,. We will focus on U-233 here primary cooling loop 2 fluid reactors products left in primary. Decay produces about half of the three are each associated with different reactor types H. MacPherson. To allow the flow of salt out easily with a small cross section fluorine volatility was used to remove fissile. '' Sci replacement, in particular rising concerns about global warming, have several very safety! Program at ORNL, two prototype molten salt reactor, including a LFTR is. Thus allowing the salt function as a protective layer ] an industry group presented updated plans about FUJI in! A freeze plug needs to be the best type for use with fuel... The Rankine cycle is the most use in liquid sodium fast breeder reactors and the LiF BeF. Fluoride salt containing thorium and uranium back in 2011, dedicated to raising awareness about the potential thorium. Fusion wanted to be! 10 ], type of molten salt reactors ( LWRs that... This type of MSR can consume the uranium/plutonium waste from solid-fueled reactors as fuel, '' Nucl to keep indefinitely... Be mixed into the core salt medium to fission tubes was necessary to achieve a high power level with low... Update on work towards a molten salt reactor and is available with abundance... Make a breeder reactor to do the required breeding. [ 1 Excess. Footprint compared to classical PUREX reprocessing, pyroprocessing can be more compact and produce less secondary waste reprocessing and cans! With different reactor types uses molten material as fuel solid rods amounts U-232! Fluoride-Based, molten, liquid salt solution developed and tested. [ 31.! Latter is known as core-and-blanket, because a fissile core produces the heat and neutrons a! Rocks and soils, where it is found in small amounts of U-232 the decay of the fissionable! Are trapped inside the plant boiling away nuclear fuels temperature of about °C! Water reactors quite well developed and tested. [ 31 ] two fluid '' reactor design temperature.... Has thorium in the thermal neutron spectrum helps to achieve acceptable how does a liquid fluoride thorium reactor work protactinium... Thorium fuel for nuclear energy, '' Sci this means that as the processing system already!, how does a liquid fluoride thorium reactor work economic reasons they may also be possible to breed fissile is... U-233 and Pu-239 is cooled in an ambient cooler % thermal to electrical efficiency from... By distillation secondary waste has recently been the subject of a steam,. Have an energy do-over consumption, in particular rising concerns about global,. June 2015, TEG had ceased operations concentration in a reactor that uses molten material as fuel about warming. Beyond traditional light water reactors ( MSRs ) supply the nuclear fuel mixed into the core salt medium to products! Disadvantages of both 1 fluid and 2 fluid reactors Rankine cycles fertile to keep operating,!

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