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Thorcon is a nuclear engineering company that is designing the ThorCon Reactor, a small modular reactor (SMR) that employs molten salt technology. The reactor design is based on the Denatured molten salt reactor (DMSR) design from Oak Ridge National Laboratory [1] and employs liquid fuel, rather than a conventional solid fuel. The liquid contains the nuclear fuel and also serves as primary coolant. [2] ThorCon plans to manufacture the reactors cheaply in shipyards employing modern ship building construction techniques.

Small modular reactors (SMRs) are a type of nuclear fission reactor which are smaller than conventional reactors, and manufactured at a plant and brought to a site to be assembled. Modular reactors allow for less on-site construction, increased containment efficiency, and heightened nuclear materials security. SMRs have been proposed as a way to bypass financial barriers that have plagued conventional nuclear reactors.

Molten salt reactor class of nuclear fission reactors with molten salt as the primary coolant or the fuel

A molten salt reactor (MSR) is a class of nuclear fission reactor in which the primary nuclear reactor coolant and/or the fuel is a molten salt mixture. MSRs offer multiple advantages over conventional nuclear power plants, although for historical reasons, they have not been deployed.

Oak Ridge National Laboratory government research facility in Tennessee, United States

Oak Ridge National Laboratory (ORNL) is an American multiprogram science and technology national laboratory sponsored by the U.S. Department of Energy (DOE) and administered, managed, and operated by UT–Battelle as a federally funded research and development center (FFRDC) under a contract with the DOE. Established in 1942, ORNL is the largest science and energy national laboratory in the Department of Energy system by size and by annual budget. ORNL is located in Oak Ridge, Tennessee, near Knoxville. ORNL's scientific programs focus on materials, neutron science, energy, high-performance computing, systems biology and national security.



In December 2015, Thorcon signed a memorandum of understanding with three Indonesian companies to develop its molten salt reactor technology in Indonesia. [3]

A memorandum of understanding (MoU) is a type of agreement between two (bilateral) or more (multilateral) parties. It expresses a convergence of will between the parties, indicating an intended common line of action. It is often used either in cases where parties do not imply a legal commitment or in situations where the parties cannot create a legally enforceable agreement. It is a more formal alternative to a gentlemen's agreement.

A 2017 study included ThorCon and seven other designs. [4] The study concludes that "if power plants featuring these technologies are able to produce electricity at the average LCOE price projected here (much less the low-end estimate), it would have a significant impact on electricity markets."

In April 2018, the United States Department of Energy awarded Thorcon $400,000 as a GAIN research project to be conducted jointly by ThorCon USA Inc and Argonne National Laboratory. [5] [6]

United States Department of Energy Cabinet-level department of the United States government concerned with U.S. policies regarding energy and safety in handling nuclear material

The United States Department of Energy (DOE) is a cabinet-level department of the United States Government concerned with the United States' policies regarding energy and safety in handling nuclear material. Its responsibilities include the nation's nuclear weapons program, nuclear reactor production for the United States Navy, energy conservation, energy-related research, radioactive waste disposal, and domestic energy production. It also directs research in genomics; the Human Genome Project originated in a DOE initiative. DOE sponsors more research in the physical sciences than any other U.S. federal agency, the majority of which is conducted through its system of National Laboratories. The agency is administered by the United States Secretary of Energy, and its headquarters are located in Southwest Washington, D.C., on Independence Avenue in the James V. Forrestal Building, named for James Forrestal, as well as in Germantown, Maryland.

Argonne National Laboratory Science and engineering research national laboratory in Lemont, IL, United States

Argonne National Laboratory is a science and engineering research national laboratory operated by the University of Chicago Argonne LLC for the United States Department of Energy located in Lemont, Illinois, outside Chicago. It is the largest national laboratory by size and scope in the Midwest.

In July 2019, Thorcon signed a deal with PAL Indonesia to study and build a 500MWe reactor, with plans to invest $1.2 billion to build a full plant in Indonesia [7] , following the completion [8] of the feasibility study [9] .


ThorCon uses modular shipbuilding production processes except the blocks are barged to the site and dropped into place. Thorcon plans to build its reactors in shipyards, It requires as much steel as a medium size, 125,000 dwt Suezmax tanker. [10] The reactor consists of two main components, steam/electrical and nuclear. The steam/electrical component features the same design and cost ($700/kw) of a 500 MWe coal plant. A 1 GWe nuclear component requires less than 400 tons of supercritical alloys and other exotic materials. [11]

Suezmax specification of the largest ships that can pass through the Suez Canal

"Suezmax" is a naval architecture term for the largest ship measurements capable of transiting the Suez Canal in a laden condition, and is almost exclusively used in reference to tankers. Since the canal has no locks, the only serious limiting factors are draft and height because of the Suez Canal Bridge.

The reactor operates at near-ambient pressure, reducing steel requirements by 50% and concrete requirements by 80% versus a conventional reactor. Little of the concrete must be reinforced. [11]

Passive cooling is needed only in the event of overheating, which first stops the reaction, and then triggers freeze valves to drain the reactor. Fluoride salt reacts with hazardous fission products iodine-131, cesium-137 and strontium-90, preventing their release. Each reactor unit operates for four years, cools for four years, and then is replaced. All recycling occurs offsite. Each power module has two siloed reactor units generating 557 MW (thermal) yielding 250 MW (electric). [12]


In addition to (low cost) thorium, a 1 GWe reactor initially requires 3,156 kg of 20% low enriched uranium along with 11 kg per day of operation. Every 8 years the fuel must be changed out. At a yellowcake cost of $66/kg, a $7.50 UF
conversion cost and $90 per separative work unit, the levelized fuel cost is 0.53 cents per kilowatt-hour. [11]

Waste product

Every 8 years 160 tons of spent fuel travel to the recycling facility, consisting of about 75% thorium, with 95% of the balance uranium. Without separation (other than removing the salt), the total fuel waste stream averages about 2 m3 per year. [11]

See also

Related Research Articles

Nuclear reactor device to initiate and control a sustained nuclear chain reaction

A nuclear reactor, formerly known as an atomic pile, is a device used to initiate and control a self-sustained nuclear chain reaction. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nuclear fission is passed to a working fluid, which in turn runs through steam turbines. These either drive a ship's propellers or turn electrical generators' shafts. Nuclear generated steam in principle can be used for industrial process heat or for district heating. Some reactors are used to produce isotopes for medical and industrial use, or for production of weapons-grade plutonium. As of early 2019, the IAEA reports there are 454 nuclear power reactors and 226 nuclear research reactors in operation around the world.

Nuclear reprocessing is the chemical separation of fission products and unused uranium from spent nuclear fuel. Originally, reprocessing was used solely to extract plutonium for producing nuclear weapons. With commercialization of nuclear power, the reprocessed plutonium was recycled back into MOX nuclear fuel for thermal reactors. The reprocessed uranium, also known as the spent fuel material, can in principle also be re-used as fuel, but that is only economical when uranium supply is low and prices are high. A breeder reactor is not restricted to using recycled plutonium and uranium. It can employ all the actinides, closing the nuclear fuel cycle and potentially multiplying the energy extracted from natural uranium by about 60 times.

Breeder reactor type of fast neutron reactor that produces more fissile material than it consumes

A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. Breeder reactors achieve this because their neutron economy is high enough to create more fissile fuel than they use, by irradiation of a fertile material, such as uranium-238 or thorium-232 that is loaded into the reactor along with fissile fuel. Breeders were at first found attractive because they made more complete use of uranium fuel than light water reactors, but interest declined after the 1960s as more uranium reserves were found, and new methods of uranium enrichment reduced fuel costs.

Fast-neutron reactor nuclear reactor in which the fission chain reaction is sustained by fast neutrons

A fast-neutron reactor (FNR) or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons, as opposed to thermal neutrons used in thermal-neutron reactors. Such a reactor needs no neutron moderator, but requires fuel that is relatively rich in fissile material when compared to that required for a thermal-neutron reactor.

Generation IV reactor classification of nuclear reactors

Generation IV reactors are a set of nuclear reactor designs currently being researched for commercial applications by the Generation IV International Forum, with technology readiness levels varying between the level requiring a demonstration, to economical competitive implementation. They are motivated by a variety of goals including improved safety, sustainability, efficiency, and cost.

Lead-cooled fast reactor

The lead-cooled fast reactor is a nuclear reactor design that features a fast neutron spectrum and molten lead or lead-bismuth eutectic coolant. Molten lead or lead-bismuth eutectic can be used as the primary coolant because lead and bismuth have low neutron absorption and relatively low melting points. Neutrons are slowed less by interaction with these heavy nuclei and therefore help make this type of reactor a fast-neutron reactor. The coolant does however serve as a neutron reflector, returning some escaping neutrons to the core. Fuel designs being explored for this reactor scheme include fertile uranium as a metal, metal oxide or metal nitride. Smaller capacity lead-cooled fast reactors can be cooled by natural convection, while larger designs use forced circulation in normal power operation, but with natural circulation emergency cooling. The reactor outlet coolant temperature is typically in the range of 500 to 600 °C, possibly ranging over 800 °C with advanced materials for later designs. Temperatures higher than 800 °C are high enough to support thermochemical production of hydrogen.

Molten-Salt Reactor Experiment

The Molten-Salt Reactor Experiment (MSRE) was an experimental molten salt reactor at the Oak Ridge National Laboratory (ORNL) researching this technology through the 1960s; constructed by 1964, it went critical in 1965 and was operated until 1969.

Peak uranium is the point in time that the maximum global uranium production rate is reached. After that peak, according to Hubbert peak theory, the rate of production enters a terminal decline. While uranium is used in nuclear weapons, its primary use is for energy generation via nuclear fission of the uranium-235 isotope in a nuclear power reactor. Each kilogram of uranium-235 fissioned releases the energy equivalent of millions of times its mass in chemical reactants, as much energy as 2700 tons of coal, but uranium-235 is only 0.7% of the mass of natural uranium. Uranium-235 is a finite non-renewable resource. There is speculation that future advances in breeder reactor technology could allow the current reserves of uranium to provide power for humanity for billions of years, thus making nuclear power a sustainable energy. However, in 2010 the International Panel on Fissile Materials said "After six decades and the expenditure of the equivalent of tens of billions of dollars, the promise of breeder reactors remains largely unfulfilled and efforts to commercialize them have been steadily cut back in most countries." But in 2016, the Russian BN-800 fast-neutron breeder reactor started producing commercially at full power.

Liquid fluoride thorium reactor

The liquid fluoride thorium reactor is a type of molten salt reactor. LFTRs use the thorium fuel cycle with a fluoride-based, molten, liquid salt for fuel. In a typical design, the liquid is pumped between a critical core and an external heat exchanger where the heat is transferred to a nonradioactive secondary salt. The secondary salt then transfers its heat to a steam turbine or closed-cycle gas turbine.

Indias three-stage nuclear power programme

India's three-stage nuclear power programme was formulated by Homi Bhabha in the 1950s to secure the country's long term energy independence, through the use of uranium and thorium reserves found in the monazite sands of coastal regions of South India. The ultimate focus of the programme is on enabling the thorium reserves of India to be utilised in meeting the country's energy requirements. Thorium is particularly attractive for India, as it has only around 1–2% of the global uranium reserves, but one of the largest shares of global thorium reserves at about 25% of the world's known thorium reserves. However, thorium is more difficult to use than uranium as a fuel because it requires breeding, and global uranium prices remain low enough that breeding is not cost effective.

The FUJI molten salt reactor is a proposed molten-salt-fueled thorium fuel cycle thermal breeder reactor, using technology similar to the Oak Ridge National Laboratory's Molten Salt Reactor Experiment – liquid fluoride thorium reactor. It was being developed by the Japanese company International Thorium Energy & Molten-Salt Technology (IThEMS), together with partners from the Czech Republic. As a breeder reactor, it converts thorium into the nuclear fuel uranium-233. To achieve reasonable neutron economy, the chosen single-salt design results in significantly larger feasible size than a two-salt reactor. Like all molten salt reactors, its core is chemically inert and under low pressure, helping to prevent explosions and toxic releases. The proposed design is rated at 200 MWe output. 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.

Thorium-based nuclear power type of power generation

Thorium-based nuclear power generation is fueled primarily by the nuclear fission of the isotope uranium-233 produced from the fertile element thorium. According to proponents, a thorium fuel cycle offers several potential advantages over a uranium fuel cycle—including much greater abundance of thorium on Earth, superior physical and nuclear fuel properties, and reduced nuclear waste production. However, development of thorium power has significant start-up costs. Proponents also cite the lack of easy weaponization potential as an advantage of thorium, while critics say that development of breeder reactors in general increases proliferation concerns. As of 2019, there are no operational thorium reactors in the world.

Thorium Energy Alliance (TEA) is a non-governmental, non-profit 501(c)3, educational organization based in the United States, which seeks to promote energy security of the world through the use of thorium as a fuel source. The potential for the use of thorium was studied extensively during the 1950s and 60s, and now worldwide interest is being revived due to limitations and issues concerning safety, economics, use and issues in the availability of other energy sources. TEA advocates thorium based nuclear power in existing reactors and primarily in next generation reactors. TEA promotes many initiatives to educate scientists, engineers, government officials, policymakers and the general public.

The Alvin Weinberg Foundation

The Alvin Weinberg Foundation was a registered UK charity, operating under the name Weinberg Next Nuclear, that campaigned for research and development into next-generation nuclear energy. In particular, it advocated advancement of Liquid Fluoride Thorium Reactor (LFTR) and other Molten Salt Reactor (MSR) technologies.

Integral Molten Salt Reactor

The Integral Molten Salt Reactor (IMSR) is a design for a small modular reactor (SMR) that employs molten salt reactor technology being developed by the Canadian company Terrestrial Energy. It is based closely on the denatured molten salt reactor (DMSR), a reactor design from Oak Ridge National Laboratory, and also incorporates elements found in the SmAHTR, a later design from the same laboratory. The IMSR belongs to the DMSR class of molten salt reactors (MSR) and hence is a "burner" reactor that employs a liquid fuel rather than a conventional solid fuel; this liquid contains the nuclear fuel and also serves as primary coolant.

Transatomic Power was an American company that designed Generation IV nuclear reactors based on molten salt reactor (MSR) technology.

Stable salt reactor

The stable salt reactor (SSR) is a nuclear reactor design proposed by Moltex Energy Ltd based in the United Kingdom and Canada.


  1. "ThorCon – Powering Up Our World".
  2. Thomas J., Dolan (2017). Molten Salt Reactors and Thorium Energy (1st ed.). Cambridge, MA, USA: Woodhead Publishing. pp. 557–564. ISBN   978-0-08-101126-3.
  3. "Indonesia and ThorCon to Develop Thorium MSR". International Thorium Energy Organization. Retrieved 12 January 2016.
  4. EIRP (July 2017). "What Will Advanced Nuclear Plants Cost?".
  5. DOE. "GAIN Voucher Recipients 1st Round - 30 Apr 2018" (PDF).
  6. DOE. "Electroanalytical Sensors for Liquid Fueled Fluoride Molten Salt Reactor" (PDF).
  7. "PAL Indonesia, Thorcon sign deal to build $1.2 billion nuclear reactor". Reuters. July 18, 2019 via
  8. "Indonesia Validates ThorCon". June 2019.
  9. "A Thorium Molten Salt Reactor when and Where You Need It". May 2019.
  10. Wang, Brian (August 27, 2018). "China and Russia looking at 27 floating nuclear reactors but ThorCon and Indonesia could scale to 100 per year". Retrieved 2018-08-29.
  11. 1 2 3 4 Wang, Brian. "China and Russia looking at 27 floating nuclear reactors but ThorCon and Indonesia could scale to 100 per year". Retrieved 2018-08-30.
  12. Wang, Brian (August 26, 2018). "Global race for transformative molten salt nuclear includes Bill Gates and China". Retrieved 2018-08-30.