Thorium-based nuclear power

Last updated

A sample of thorium Thorium sample 0.1g.jpg
A sample of thorium

Thorium-based nuclear power generation is fueled primarily by the nuclear fission of the isotope uranium-233 produced from the fertile element thorium. A thorium fuel cycle can offer several potential advantages over a uranium fuel cycle [Note 1] — including the much greater abundance of thorium found on Earth, superior physical and nuclear fuel properties, and reduced nuclear waste production. One advantage of thorium fuel is its low weaponization potential; it is difficult to weaponize the uranium-233/232 and plutonium-238 isotopes that are largely consumed in thorium reactors.


After studying the feasibility of using thorium, nuclear scientists Ralph W. Moir and Edward Teller suggested that thorium nuclear research should be restarted after a three-decade shutdown and that a small prototype plant should be built. [1] [2] [3] Between 1999 and 2021, the number of operational thorium reactors in the world has risen from zero, [4] to a handful of research reactors, [5] to commercial plans for producing full-scale thorium-based reactors for use as power plants on a national scale. [6] [7] [5]

Some believe thorium is key to developing a new generation of cleaner, safer nuclear power. [8] [7] In 2011 a group of scientists at the Georgia Institute of Technology assessed thorium-based power as "a 1000+ year solution or a quality low-carbon bridge to truly sustainable energy sources solving a huge portion of mankind's negative environmental impact." [9] However, development of thorium power has significant start-up costs. Development of breeder reactors in general (including thorium reactors, which are breeders by nature) will increase proliferation concerns.

Background and brief history

Early thorium-based (MSR) nuclear reactor at Oak Ridge National Laboratory in the 1960s Thorium reactor ORNL.jpg
Early thorium-based (MSR) nuclear reactor at Oak Ridge National Laboratory in the 1960s

After World War II, uranium-based nuclear reactors were built to produce electricity. These were similar to the reactor designs that produced material for nuclear weapons. During that period, the government of the United States also built an experimental molten salt reactor using U-233 fuel, the fissile material created by bombarding thorium with neutrons. The MSRE reactor, built at Oak Ridge National Laboratory, operated critical for roughly 15,000 hours from 1965 to 1969. In 1968, Nobel laureate and discoverer of plutonium, Glenn Seaborg, publicly announced to the Atomic Energy Commission, of which he was chairman, that the thorium-based reactor had been successfully developed and tested. [10]

In 1973, however, the US government settled on uranium technology and largely discontinued thorium-related nuclear research. The reasons were that uranium-fueled reactors were more efficient, the research was proven, and thorium's breeding ratio was thought insufficient to produce enough fuel to support development of a commercial nuclear industry. As Moir and Teller later wrote, "The competition came down to a liquid metal fast breeder reactor (LMFBR) on the uranium-plutonium cycle and a thermal reactor on the thorium-233U cycle, the molten salt breeder reactor. The LMFBR had a larger breeding rate ... and won the competition." In their opinion, the decision to stop development of thorium reactors, at least as a backup option, "was an excusable mistake." [1]

Science writer Richard Martin states that nuclear physicist Alvin Weinberg, who was director at Oak Ridge and primarily responsible for the new reactor, lost his job as director because he championed development of the safer thorium reactors. [11] [12] Weinberg himself recalls this period:

[Congressman] Chet Holifield was clearly exasperated with me, and he finally blurted out, "Alvin, if you are concerned about the safety of reactors, then I think it may be time for you to leave nuclear energy." I was speechless. But it was apparent to me that my style, my attitude, and my perception of the future were no longer in tune with the powers within the AEC. [13]

Martin explains that Weinberg's unwillingness to sacrifice potentially safe nuclear power for the benefit of military uses forced him to retire:

Weinberg realized that you could use thorium in an entirely new kind of reactor, one that would have zero risk of meltdown. ... his team built a working reactor ... and he spent the rest of his 18-year tenure trying to make thorium the heart of the nation's atomic power effort. He failed. Uranium reactors had already been established, and Hyman Rickover, de facto head of the US nuclear program, wanted the plutonium from uranium-powered nuclear plants to make bombs. Increasingly shunted aside, Weinberg was finally forced out in 1973. [14]

Despite the documented history of thorium nuclear power, many of today's nuclear experts were nonetheless unaware of it. According to Chemical & Engineering News , "most people—including scientists—have hardly heard of the heavy-metal element and know little about it", noting a comment by a conference attendee that "it's possible to have a Ph.D. in nuclear reactor technology and not know about thorium energy." [15] Nuclear physicist Victor J. Stenger, for one, first learned of it in 2012:

It came as a surprise to me to learn recently that such an alternative has been available to us since World War II, but not pursued because it lacked weapons applications. [16]

Others, including former NASA scientist and thorium expert Kirk Sorensen, agree that "thorium was the alternative path that was not taken". [17] [18] :2 According to Sorensen, during a documentary interview, he states that if the US had not discontinued its research in 1974 it could have "probably achieved energy independence by around 2000." [19]

Possible benefits

Summarizing some of the potential benefits, Martin offers his general opinion: "Thorium could provide a clean and effectively limitless source of power while allaying all public concern—weapons proliferation, radioactive pollution, toxic waste, and fuel that is both costly and complicated to process." [18] :13 Moir and Teller estimated in 2004 that the cost for their recommended prototype would be "well under $1 billion with operation costs likely on the order of $100 million per year", and as a result a "large-scale nuclear power plan" usable by many countries could be set up within a decade. [1]

A report by the Bellona Foundation in 2013 concluded that the economics are quite speculative. Thorium nuclear reactors are unlikely to produce cheaper energy, but the management of spent fuel is likely to be cheaper than for uranium nuclear reactors. [31]

Possible disadvantages

Some experts note possible specific disadvantages of thorium nuclear power:

Notable proponents of thorium

Nobel laureate in physics and former director of CERN Carlo Rubbia has long been a fan of thorium. According to Rubbia, "In order to be vigorously continued, nuclear power must be profoundly modified". [36]

Hans Blix, former director general of the International Atomic Energy Agency, has said "Thorium fuel gives rise to waste that is smaller in volume, less toxic and much less long lived than the wastes that result from uranium fuel". [37]

Thorium-based nuclear power projects

Research and development of thorium-based nuclear reactors, primarily the liquid fluoride thorium reactor (LFTR), MSR design, has been or is now being done in the United States, United Kingdom, Germany, Brazil, India, China, France, the Czech Republic, Japan, Russia, Canada, Israel, Denmark and the Netherlands. [16] [18] Conferences with experts from as many as 32 countries are held, including one by the European Organization for Nuclear Research (CERN) in 2013, which focuses on thorium as an alternative nuclear technology without requiring production of nuclear waste. [38] Recognized experts, such as Hans Blix, former head of the International Atomic Energy Agency, calls for expanded support of new nuclear power technology, and states, "the thorium option offers the world not only a new sustainable supply of fuel for nuclear power but also one that makes better use of the fuel's energy content." [39]


CANDU reactors are capable of using thorium, [40] [41] and Thorium Power Canada has, in 2013, planned and proposed developing thorium power projects for Chile and Indonesia. [42] The proposed 10 MW demonstration reactor in Chile could be used to power a 20 million litre/day desalination plant. In 2018, the New Brunswick Energy Solutions Corporation announced the participation of Moltex Energy in the nuclear research cluster that will work on research and development on small modular reactor technology. [43] [44] [45]


At the 2011 annual conference of the Chinese Academy of Sciences, it was announced that "China has initiated a research and development project in thorium MSR technology." [46] In addition, Dr. Jiang Mianheng, son of China's former leader Jiang Zemin, led a thorium delegation in non-disclosure talks at Oak Ridge National Laboratory, Tennessee, and by late 2013 China had officially partnered with Oak Ridge to aid China in its own development. [47] [48] The World Nuclear Association notes that the China Academy of Sciences in January 2011 announced its R&D program, "claiming to have the world's largest national effort on it, hoping to obtain full intellectual property rights on the technology." [21] According to Martin, "China has made clear its intention to go it alone," adding that China already has a monopoly over most of the world's rare earth minerals. [18] :157 [26]

In March 2014, with their reliance on coal-fired power having become a major cause of their current "smog crisis", they reduced their original goal of creating a working reactor from 25 years down to 10. "In the past, the government was interested in nuclear power because of the energy shortage. Now they are more interested because of smog", said Professor Li Zhong, a scientist working on the project. "This is definitely a race", he added. [49]

In early 2012, it was reported that China, using components produced by the West and Russia, planned to build two prototypes, one of them a molten salt-cooled pebble-bed reactor by 2015, [50] :minute 1:37 and a research molten salt reactor by 2017, [50] had budgeted the project at $400 million and requiring 400 workers. [18] China also finalized an agreement with a Canadian nuclear technology company to develop improved CANDU reactors using thorium and uranium as a fuel. [51] By 2019 two of the reactors were under construction in the Gobi desert, with completion expected around 2025. China expects to put thorium reactors into commercial use by 2030. [5] At least one of the 2MW thorium prototypes, [50] either a molten salt reactor, [50] :minute 54:00 or a molten salt-cooled reactor, [50] :minute 44:20 is nearing completion, with startup in September 2021. [52] [53]

As of 24 June 2021, China has reported that the Gobi Molten salt reactor will be completed on schedule with tests beginning as early as September 2021. The new reactor is a part of Chinese leader Xi Jinping's drive to make China carbon-neutral by 2060. [54] China hopes to complete the world's first commercial Thorium reactor by 2030 and has planned to further build more Thorium power plants across the low populated deserts and plains of western China, as well as up to 30 nations involved in China's Belt and Road Initiative. [54] [55] [56] See TMSR-LF1

Germany, 1980s

The German THTR-300 was a prototype commercial power station using thorium as fertile and highly enriched U-235 as fissile fuel. Though named thorium high temperature reactor, mostly U-235 was fissioned. The THTR-300 was a helium-cooled high-temperature reactor with a pebble-bed reactor core consisting of approximately 670,000 spherical fuel compacts each 6 centimetres (2.4 in) in diameter with particles of uranium-235 and thorium-232 fuel embedded in a graphite matrix. It fed power to Germany's grid for 432 days in the late 1980s, before it was shut down for cost, mechanical and other reasons.


India has the largest supplies of thorium in the world, with comparatively poor quantities of uranium. India has projected meeting as much as 30% of its electrical demands through thorium by 2050. [57]

In February 2014, Bhabha Atomic Research Centre (BARC), in Mumbai, India, presented their latest design for a "next-generation nuclear reactor" that burns thorium as its fuel ore, calling it the Advanced Heavy Water Reactor (AHWR). They estimated the reactor could function without an operator for 120 days. [58] Validation of its core reactor physics was underway by late 2017. [59]

According to Dr R K Sinha, chairman of their Atomic Energy Commission, "This will reduce our dependence on fossil fuels, mostly imported, and will be a major contribution to global efforts to combat climate change." Because of its inherent safety, they expect that similar designs could be set up "within" populated cities, like Mumbai or Delhi. [58]

Indian government is also developing up to 62 reactors, mostly thorium-based, which it expects to be operational by 2025. India is the "only country in the world with a detailed, funded, government-approved plan" to focus on thorium-based nuclear power. The country currently gets under 2% of its electricity from nuclear power, with the rest coming from coal (60%), hydroelectricity (16%), other renewable sources (12%) and natural gas (9%). [60] It expects to produce around 25% of its electricity from nuclear power. [18] In 2009 the chairman of the Indian Atomic Energy Commission said that India has a "long-term objective goal of becoming energy-independent based on its vast thorium resources to meet India's economic ambitions." [61] [62]

In late June 2012, India announced that their "first commercial fast reactor" was near completion, making India the most advanced country in thorium research. "We have huge reserves of thorium. The challenge is to develop technology for converting this to fissile material," stated their former Chairman of India's Atomic Energy Commission. [63] That vision of using thorium in place of uranium was set out in the 1950s by physicist Homi Bhabha. [64] [65] [66] [67] India's first commercial fast breeder reactor—the 500 MWe Prototype Fast Breeder Reactor (PFBR)—is approaching completion at the Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu.

As of July 2013 the major equipment of the PFBR had been erected and the loading of "dummy" fuels in peripheral locations was in progress. The reactor was expected to go critical by September 2014. [68] The Centre had sanctioned Rs. 5,677 crore for building the PFBR and "we will definitely build the reactor within that amount," Mr. Kumar asserted. The original cost of the project was Rs. 3,492 crore, revised to Rs. 5,677 crore. Electricity generated from the PFBR would be sold to the State Electricity Boards at Rs. 4.44 a unit. BHAVINI builds breeder reactors in India.

In 2013 India's 300 MWe AHWR (pressurized heavy water reactor) was slated to be built at an undisclosed location. [69] The design envisages a start up with reactor grade plutonium that breeds U-233 from Th-232. Thereafter, thorium is to be the only fuel. [70] As of 2017, the design was in the final stages of validation. [71]

Delays have since postponed the commissioning [criticality?] of the PFBR to September 2016, [72] but India's commitment to long-term nuclear energy production is underscored by the approval in 2015 of ten new sites for reactors of unspecified types, [73] though procurement of primary fissile material—preferably plutonium—may be problematic due to India's low uranium reserves and capacity for production. [74]


P3Tek, an agency of the Indonesia Ministry of Energy and Mineral Resource, has reviewed a thorium molten salt reactor by Thorcon called the TMSR-500. The study reported that building a ThorCon TMSR-500 would meet Indonesia's regulations for nuclear energy safety and performance. [75]


In May 2010, researchers from Ben-Gurion University of the Negev in Israel and Brookhaven National Laboratory in New York began to collaborate on the development of thorium reactors, [76] aimed at being self-sustaining, "meaning one that will produce and consume about the same amounts of fuel," which is not possible with uranium in a light water reactor. [76]


In June 2012, Japan utility Chubu Electric Power wrote that they regard thorium as "one of future possible energy resources." [77]


In late 2012, Norway's privately owned Thor Energy, in collaboration with the government and Westinghouse, announced a four-year trial using thorium in an existing nuclear reactor." [78] In 2013, Aker Solutions purchased patents from Nobel Prize winning physicist Carlo Rubbia for the design of a proton accelerator-based thorium nuclear power plant. [79]

United Kingdom

In Britain, one organisation promoting or examining research on thorium-based nuclear plants is The Alvin Weinberg Foundation. House of Lords member Bryony Worthington is promoting thorium, calling it "the forgotten fuel" that could alter Britain's energy plans. [80] However, in 2010, the UK's National Nuclear Laboratory (NNL) concluded that for the short to medium term, "...the thorium fuel cycle does not currently have a role to play," in that it is "technically immature, and would require a significant financial investment and risk without clear benefits," and concluded that the benefits have been "overstated." [21] [31] Friends of the Earth UK considers research into it as "useful" as a fallback option. [81]

United States

In its January 2012 report to the United States Secretary of Energy, the Blue Ribbon Commission on America's Future notes that a "molten-salt reactor using thorium [has] also been proposed." [82] That same month it was reported that the US Department of Energy is "quietly collaborating with China" on thorium-based nuclear power designs using an MSR. [83]

Some experts and politicians want thorium to be "the pillar of the U.S. nuclear future." [84] Senators Harry Reid and Orrin Hatch have supported using $250 million in federal research funds to revive ORNL research. [9] In 2009, Congressman Joe Sestak unsuccessfully attempted to secure funding for research and development of a destroyer-sized reactor [reactor of a size to power a destroyer] using thorium-based liquid fuel. [85] [86]

Alvin Radkowsky, chief designer of the world's second full-scale atomic electric power plant in Shippingport, Pennsylvania, founded a joint US and Russian project in 1997 to create a thorium-based reactor, considered a "creative breakthrough." [87] In 1992, while a resident professor in Tel Aviv, Israel, he founded the US company, Thorium Power Ltd., near Washington, D.C., to build thorium reactors. [87]

The primary fuel of the proposed HT3R research project near Odessa, Texas, United States, will be ceramic-coated thorium beads. The reactor construction has not yet begun. [88] Estimates to complete a reactor were originally set at ten years in 2006 (with a proposed operational date of 2015). [89]

On the research potential of thorium-based nuclear power, Richard L. Garwin, winner of the Presidential Medal of Freedom, and Georges Charpak advise further study of the Energy amplifier in their book Megawatts and Megatons (2001), pp. 153–63.

While not technically a molten salt reactor, another more recent example of a Thorium reactor is currently under development by a company called TerraPower. Founded by Bill Gates, TerraPower is developing a sodium-cooled fast reactor called Natrium, [90] which plans to build a pilot plant in Wyoming and enjoys the financial backing of Bill Gates and Warren Buffett. [54] The Natrium power plant could also act as a repository for excess energy from renewables by dumping the energy into a heat tank. [91]

World sources of thorium

World thorium reserves (2007) [92]
CountryTons %
Greenland (Denmark)54,0002.1%
South Africa18,0000.7%
Other countries33,0001.2%
World Total2,610,000100.0%

Thorium is mostly found with the rare earth phosphate mineral, monazite, which contains up to about 12% thorium phosphate, but 6–7% on average. World monazite resources are estimated to be about 12 million tons, two-thirds of which are in heavy mineral sands deposits on the south and east coasts of India. There are substantial deposits in several other countries (see table "World thorium reserves"). [21] Monazite is a good source of REEs (rare earth elements), but monazites are currently not economical to produce because the radioactive thorium that is produced as a byproduct would have to be stored indefinitely. However, if thorium-based power plants were adopted on a large-scale, virtually all the world's thorium requirements could be supplied simply by refining monazites for their more valuable REEs. [93]

Another estimate of reasonably assured reserves (RAR) and estimated additional reserves (EAR) of thorium comes from OECD/NEA, Nuclear Energy, "Trends in Nuclear Fuel Cycle", Paris, France (2001). [94] (see table "IAEA Estimates in tons")

IAEA Estimates in tons (2005)
CountryRAR ThEAR Th
South Africa18,0001%
Other countries33,0002%
World Total2,810,000100%

The preceding figures are reserves and as such refer to the amount of thorium in high-concentration deposits inventoried so far and estimated to be extractable at current market prices; millions of times more total exist in Earth's 3×1019 tonne crust, around 120 trillion tons of thorium, and lesser but vast quantities of thorium exist at intermediate concentrations. [95] [96] Proved reserves are a good indicator of the total future supply of a mineral resource.

Types of thorium-based reactors

According to the World Nuclear Association, there are seven types of reactors that can be designed to use thorium as a nuclear fuel. Six of these have all entered into operational service at some point. The seventh is still conceptual, although currently in development by many countries: [21]

See also


  1. A nuclear reactor consumes certain specific fissile isotopes to produce energy. Currently, the most common types of nuclear reactor fuel are:

Related Research Articles

Nuclear reactor Device used to initiate and control a nuclear chain reaction

A nuclear reactor, formerly known as an atomic pile, is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. 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 fuel cycle Process of manufacturing and consuming nuclear fuel

The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear fuel through a series of differing stages. It consists of steps in the front end, which are the preparation of the fuel, steps in the service period in which the fuel is used during reactor operation, and steps in the back end, which are necessary to safely manage, contain, and either reprocess or dispose of spent nuclear fuel. If spent fuel is not reprocessed, the fuel cycle is referred to as an open fuel cycle ; if the spent fuel is reprocessed, it is referred to as a closed fuel cycle.

Nuclear reprocessing

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 nuclear reactor

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 Type of nuclear reactor

A fast-neutron reactor (FNR) or fast-spectrum reactor 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.

Molten salt reactor Type of nuclear reactor cooled by molten material

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. Only two MSRs have ever operated, both research reactors in the United States. The 1950's Aircraft Reactor Experiment was primarily motivated by the compact size that the technique offers, while the 1960's Molten-Salt Reactor Experiment aimed to prove the concept of a nuclear power plant which implements a thorium fuel cycle in a breeder reactor. Increased research into Generation IV reactor designs began to renew interest in the technology, with multiple nations having projects and, as of September 2021, China is on the verge of starting its TMSR-LF1 thorium MSR.

Nuclear fuel Material used in nuclear power stations

Nuclear fuel is material used in nuclear power stations to produce heat to power turbines. Heat is created when nuclear fuel undergoes nuclear fission.

Bhabha Atomic Research Centre Nuclear research facility in Mumbai, India

The Bhabha Atomic Research Centre (BARC) formerly known as Atomic Energy Establishment, Trombay is India's premier nuclear research facility, headquartered in Trombay, Mumbai, Maharashtra. Founded by Homi Jehangir Bhabha Atomic Energy Establishment, Trombay (AEET) in January 1954 as a multidisciplinary research program essential for the india's nuclear program. It operates under the Department of Atomic Energy(DAE) which is directly overseen by the Prime Minister of India. In 1966 after the death of Homi Jehangir Bhabha AEET renamed as Bhabha Atomic Research Centre (BARC) BARC is a multi-disciplinary research centre with extensive infrastructure for advanced research and development covering the entire spectrum of nuclear science, chemical engineering, material sciences & metallurgy, electronic instrumentation, biology and medicine, supercomputing, high-energy physics and Plasma physics and associated research for Indian nuclear programme and related areas.

Uranium-233 (233U) is a fissile isotope of uranium that is bred from thorium-232 as part of the thorium fuel cycle. Uranium-233 was investigated for use in nuclear weapons and as a reactor fuel. It has been used successfully in experimental nuclear reactors and has been proposed for much wider use as a nuclear fuel. It has a half-life of 160,000 years.

Uranium (92U) is a naturally occurring radioactive element that has no stable isotope. It has two primordial isotopes, uranium-238 and uranium-235, that have long half-lives and are found in appreciable quantity in the Earth's crust. The decay product uranium-234 is also found. Other isotopes such as uranium-233 have been produced in breeder reactors. In addition to isotopes found in nature or nuclear reactors, many isotopes with far shorter half-lives have been produced, ranging from 214U to 242U. The standard atomic weight of natural uranium is 238.02891(3).

Generation IV reactor New nuclear reactor technologies under development

Generation IV reactors are a set of nuclear reactor designs currently being researched for commercial applications by the Generation IV International Forum. They are motivated by a variety of goals including improved safety, sustainability, efficiency, and cost.

Thorium fuel cycle Nuclear fuel cycle

The thorium fuel cycle is a nuclear fuel cycle that uses an isotope of thorium, 232
, as the fertile material. In the reactor, 232
is transmuted into the fissile artificial uranium isotope 233
which is the nuclear fuel. Unlike natural uranium, natural thorium contains only trace amounts of fissile material, which are insufficient to initiate a nuclear chain reaction. Additional fissile material or another neutron source is necessary to initiate the fuel cycle. In a thorium-fuelled reactor, 232
absorbs neutrons to produce 233
. This parallels the process in uranium breeder reactors whereby fertile 238
absorbs neutrons to form fissile 239
. Depending on the design of the reactor and fuel cycle, the generated 233
either fissions in situ or is chemically separated from the used nuclear fuel and formed into new nuclear fuel.

The advanced heavy-water reactor (AHWR) or AHWR-300 is the latest Indian design for a next-generation nuclear reactor that burns thorium in its fuel core. It is slated to form the third stage in India's three-stage fuel-cycle plan. This phase of the fuel cycle plan is supposed to be built starting with a 300MWe prototype in 2016. As of 2021 construction has not started and a firm date has not be set.

Molten-Salt Reactor Experiment Nuclear reactor, Oak Ridge 1965–1969

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. The costs of a cleanup project were estimated at about $130 million.

The Prototype Fast Breeder Reactor (PFBR) is a 500 MWe fast breeder nuclear reactor presently being constructed at the Madras Atomic Power Station (MAPS) in Kalpakkam, India. The Indira Gandhi Centre for Atomic Research (IGCAR) is responsible for the design of this reactor. The facility builds on the decades of experience gained from operating the lower power Fast Breeder Test Reactor (FBTR). Originally planned to be commissioned in 2010, the construction of the reactor suffered from multiple delays. As of August 2020, criticality is planned to be achieved in 2021.

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.

Liquid fluoride thorium reactor Type of nuclear reactor that uses molten material as fuel

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, the well-known physicist, 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.

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.

Copenhagen Atomics is a Danish molten salt technology company developing mass manufacturable molten salt reactors. The company headquarters are co-located with Alfa Laval in Copenhagen.


  1. 1 2 3 4 5 Moir, Ralph W. and Teller, Edward. "Thorium-fuelled Reactor Using Molten Salt Technology", Journal of Nuclear Technology, September 2005 Vol 151 (PDF file available). This article was Teller's last, published after his death in 2003.
  2. Hargraves, Robert and Moir, Ralph. "Liquid Fluoride Thorium Reactors: An old idea in nuclear power gets reexamined", American Scientist , Vol. 98, p. 304 (2010).
  3. Barton, Charles. "Edward Teller, Global Warming, and Molten Salt Reactors", Nuclear Green Revolution, 1 March 2008
  4. "Uses For Uranium-233: What Should Be Kept for Future Needs?" (PDF). 27 September 1999. Retrieved 30 March 2020.
  5. 1 2 3 "How China hopes to play a leading role in developing next-generation nuclear reactors".
  6. Thorcon design document: (2010) Powering up our world with cheap, reliable, CO2-free electric power, now.
  7. 1 2 Use Molten salts— Flibe both as fuel and as coolant transfer fluid: (2020) Molten-Salt Reactor Choices - Kirk Sorensen of Flibe Energy Keep operational temperatures below 700 °C, use prismatic graphite as moderator, pump the molten salts from one reactor vessel in cooldown stage to the active, operating reactor vessel. Mitigate tritium using the CO2 cycle in the supercritical CO2 power conversion system; capture the tritium with the oxygen in the supercritical CO2 as mitigated water. This approach keeps the materials in chemical equilibrium during the process, while reducing the volume of waste materials such as CO2, with shorter radioactive half-lives than the uranium series' half-life.
  8. "The Energy From Thorium Foundation Thorium". 30 August 2010. Retrieved 6 September 2013.
  9. 1 2 Cooper, Nicolas (2011). "Should We Consider Using Liquid Fluoride Thorium Reactors for Power Generation?". Environmental Science. 45 (15): 6237–38. Bibcode:2011EnST...45.6237C. doi:10.1021/es2021318. PMID   21732635.
  10. "Viability of thorium-based nuclear fuel cycle for the next generation nuclear reactor: Issues and prospects". Renewable and Sustainable Energy Reviews. 97: 259–275. 1 December 2018. doi:10.1016/j.rser.2018.08.019 via
  11. Weinberg Foundation Archived 31 December 2015 at the Wayback Machine , Main website, London, UK
  12. Pentland, William. "Is Thorium the Biggest Energy Breakthrough Since Fire? Possibly" Forbes, 11 September 2011
  13. "LFTR in 10 Minutes, video presentation
  14. Martin, Richard. "Uranium Is So Last Century – Enter Thorium, the New Green Nuke", Wired magazine, Dec. 21, 2009
  15. Jacoby, Mitch (16 November 2009). "Reintroducing Thorium". Chemical & Engineering News . Vol. 87 no. 46. pp. 44–46.
  16. 1 2 Stenger, Victor J. (9 January 2012). "LFTR: A Long-Term Energy Solution?". Huffington Post.
  17. "Energy From Thorium", talk at Google Tech Talks, 23 July 2009, video, 1 hr. 22 min.
  18. 1 2 3 4 5 6 7 8 Martin, Richard. Superfuel: Thorium, the Green Energy Source for the Future. Palgrave–Macmillan (2012)
  19. "The Thorium Dream", Motherboard TV video documentary, 28 min.
  20. 1 2 Goswami, D. Yogi, ed. The CRC Handbook of Mechanical Engineering, Second Edition, CRC Press (2012) pp. 7–45
  21. 1 2 3 4 5 6 7 8 Thorium, World Nuclear Association
  22. 1 2 Evans-Pritchard, Ambrose. "Obama could kill fossil fuels overnight with a nuclear dash for thorium", The Telegraph, UK 29 August 2010
  23. "Alvin Radkowsky, 86, Developer Of a Safer Nuclear Reactor Fuel", obituary, New York Times, 5 March 2002
  24. Langford, R. Everett (2004). Introduction to Weapons of Mass Destruction: Radiological, Chemical, and Biological. Hoboken, NJ: John Wiley & Sons. p. 85. ISBN   978-0-471-46560-7..
  25. Ford, James and Schuller, C. Richard. Controlling threats to nuclear security a holistic model , pp. 111–12 (United States Government Printing Office 1997).
  26. 1 2 Evans-Pritchard, Ambrose. "Safe nuclear does exist, and China is leading the way with thorium" Telegraph, UK, 20 March 2011
  27. 1 2 "American Science LFTR" (PDF). Archived from the original (PDF) on 8 December 2013.
  29. Juhasz, Albert J.; Rarick, Richard A.; Rangarajan, Rajmohan. "High Efficiency Nuclear Power Plants Using Liquid Fluoride Thorium Reactor Technology" (PDF). NASA. Retrieved 27 October 2014.
  30. International Atomic Energy Agency. "Thorium fuel cycle – Potential benefits and challenges" (PDF). Retrieved 27 October 2014.
  31. 1 2 3 Andreev, Leonid (2013). Certain issues of economic prospects of thorium-based nuclear energy systems (PDF) (Report). Bellona Foundation. Retrieved 10 March 2017.
  32. Mathieu, L. (2006). "The thorium molten salt reactor: Moving on from the MSBR" (PDF). Progress in Nuclear Energy. 48 (7): 664–79. arXiv: nucl-ex/0506004v1 . doi:10.1016/j.pnucene.2006.07.005. S2CID   15091933.
  33. Nelson, Andrew T. (September–October 2012). "Thorium: Not a near-term commercial nuclear fuel". Bulletin of the Atomic Scientists. 68 (5): 33–44. Bibcode:2012BuAtS..68e..33N. doi:10.1177/0096340212459125. S2CID   144725888.
  34. ""Superfuel" Thorium a Proliferation Risk?". 5 December 2012.
  35. Uribe, Eva C. "Thorium power has a protactinium problem". Bulletin of the Atomic Scientists. Retrieved 7 August 2018.
  36. "Thorium trumps all fuels as energy source".
  37. "Hans Blix: Nuclear must use thorium fuel to reduce weapons risk". ZDnet.
  38. "CERN to host conference on thorium technologies for energy" Archived 19 October 2013 at the Wayback Machine , India Blooms, 17 October 2013
  39. "Lightbridge Corp : Hans Blix Urges Support for Thorium Power Development", 11 October 2013
  40. "Nuclear's future: Fission or fizzle?". Archived from the original on 27 August 2011.
  41. Sahin, S; Yildiz, K; Sahin, H; Acir, A (2006). "Investigation of CANDU reactors as a thorium burner". Energy Conversion and Management. 47 (13–14): 1661. doi:10.1016/j.enconman.2005.10.013.
  42. "Thorium Power Canada is in advanced talks with Chile and Indonesia for 10 MW and 25 MW solid thorium fueled reactors", 1 July 2013
  43. Government of New Brunswick, Canada (13 July 2018). "Moltex to partner in nuclear research and innovation cluster".
  44. "Second company investing in nuclear technology in N.B." Global News.
  45. "UK Moltex seeks to deploy its Stable Salt Reactor in Canada - Nuclear Engineering International".
  46. Initiates Thorium MSR Project « Energy from Thorium. (30 January 2011). Retrieved on 2011-05-01.
    Kamei, Takashi; Hakami, Saeed (2011). "Evaluation of implementation of thorium fuel cycle with LWR and MSR". Progress in Nuclear Energy. 53 (7): 820. doi:10.1016/j.pnucene.2011.05.032.
    Martin, Richard. "China Takes Lead in Race for Clean Nuclear Power", Wired, 1 February 2011
  47. "The U.S. government lab behind China's nuclear power push", Reuters, 20 December 2013
  48. "Watch replay of nuclear's future, with dash of rare earth, political intrigue", Smart Planet, 23 December 2011, includes video
  49. "Chinese scientists urged to develop new thorium nuclear reactors by 2024", South China Morning Post, 19 March 2014
  50. 1 2 3 4 5 Kun Chen from Chinese Academy of Sciences on China Thorium Molten Salt Reactor TMSR Program (2012)
  51. "Candu Signs Expanded Agreement with China to Further Develop Recycled Uranium and Thorium Fuelled CANDU Reactors", Canada Newswire, 2 August 2012
  52. Nick Lavars (20 Jul 2021) China adding finishing touches to world-first thorium nuclear reactor
  53. Smriti Mallapaty (9 Sep 2021) China prepares to test thorium-fuelled nuclear reactor
  54. 1 2 3 Ben, Turner (24 June 2021). "China Creates New Thorium Reactor". Live Science. Retrieved 10 August 2021.
  55. "China adding finishing touches to world-first thorium nuclear reactor". New Atlas. 20 July 2021. Retrieved 30 September 2021.
  56. "China Says It's Closing in on Thorium Nuclear Reactor". IEEE Spectrum. 4 August 2021. Retrieved 30 September 2021.
  57. Katusa, Marin (16 February 2012). "The Thing About Thorium: Why The Better Nuclear Fuel May Not Get A Chance". Forbes. p. 2. Retrieved 17 November 2014.
  58. 1 2 "Design of World's first Thorium based nuclear reactor is ready", India Today, 14 February 2014
  59. Jha, Saurav (12 December 2017), "India's research fleet",, retrieved 1 July 2018
  60. Energy policy of India#Power Generation capacity in India
  61. "Considering an Alternative Fuel for Nuclear Energy", The New York Times, 19 October 2009
  62. "India's experimental Thorium Fuel Cycle Nuclear Reactor [NDTV Report] on YouTube 2010, 7 minutes
  63. "First commercial fast reactor nearly ready", The Hindu, 29 June 2012
  64. Rahman, Maseeh (1 November 2011). "How Homi Bhabha's vision turned India into a nuclear R&D leader". Mumbai: Guardian. Retrieved 1 March 2012.
  65. "A future energy giant? India's thorium-based nuclear plans". 1 October 2010. Retrieved 4 March 2012.
  66. Chalmers, Matthew (2010). "Enter the thorium tiger". Physics World. 23 (10): 40–45. Bibcode:2010PhyW...23j..40C. doi:10.1088/2058-7058/23/10/35. ISSN   2058-7058.
  67. "India plans 'safer' nuclear plant powered by thorium", The Guardian, 1 November 2011
  68. Special Correspondent (1 July 2013). "India's Prototype Fast Breeder Reactor at advanced stage of completion". The Hindu. Retrieved 17 October 2013.
  69. "Press Information Bureau".
  70. Krivit, Steven; Lehr, Jay H (2011). Nuclear Energy Encyclopedia: Science, Technology, and Applications. p. 89. ISBN   978-1-118-04347-9.
  71. "Fuel for India's nuclear ambitions". Nuclear Engineering International. 7 April 2017. Retrieved 12 April 2017.
  72. "PFBR: Parliamentary panel slams govt for 'inordinate delays'". The Economic Times.
  73. "Business News Today: Read Latest Business news, India Business News Live, Share Market & Economy News". The Economic Times.
  74. Prabhu, Jaideep A. "Fast forwarding to thorium".
  75. "P3Tek Recommends Thorcon Molten Salt Nuclear Reactor for Indonesia |" . Retrieved 17 May 2021.
  76. 1 2 "Self-sustaining nuclear energy from Israel" Israel21c News Service, 11 October 2010
  77. Halper, Mark. "Safe nuclear: Japanese utility elaborates on thorium plans" Smart Planet, 7 June 2012
  78. "Norway ringing in thorium nuclear New Year with Westinghouse at the party", Smartplanet, 23 November 2012
  79. Boyle, Rebecca (30 August 2010). "Development of Tiny Thorium Reactors Could Wean the World Off Oil In Just Five Years | Popular Science". Retrieved 6 September 2013.
  80. "The Thorium Lord", Smart Planet, 17 June 2012
  81. Childs, Mike (24 March 2011). "Thorium reactors and nuclear fusion". Friends of the Earth UK. Archived from the original on 7 July 2011.
  82. Blue Ribbon Commission Report Archived 7 August 2012 at the Wayback Machine , January 2012
  83. Halper, Mark. "U.S. partners with China on new nuclear", Smart Planet, 26 June 2012
  84. "U-turn on Thorium" Future Power Technology, July 2012 pp. 23–24
  85. Congressman Sestak's Amendments in National Defense Authorization Act Pass House, News Blaze, 30 May 2010
  86. H.R. 1534 (111th) "To direct the Secretary of Defense and the Chairman of the Joint Chiefs of Staff to jointly carry out a study on the use of thorium-liquid fueled nuclear reactors for naval power needs, and for other purposes." Introduced: 16 March 2009 Status: Died (Referred to Committee)
  87. 1 2 Friedman, John S., Bulletin of the Atomic Scientists, September 1997 pp. 19–20
  88. Paul, Corey (8 September 2016). "UTPB, private company to push for advanced reactor". OA Online.
  89. Lobsenz, George (23 February 2006). "Advanced reactor plan gets off the ground in Texas" (PDF). The Energy Daily. Archived from the original (PDF) on 17 July 2011.
  90. "How Molten Salt Reactors Could Lead to the Next Energy Production Boom". 23 July 2021. Retrieved 10 August 2021.
  91. Wald, Matt (10 August 2021). "The Natrium System Will Enable a Carbon-Free Future".
  92. Data taken from Uranium 2007: Resources, Production and Demand, Nuclear Energy Agency (2008), NEA#6345 ( ISBN   978-9264047662). Link to a PDF version: The 2009 figures are largely unchanged. Australian data from Thorium, in Australian Atlas of Minerals Resources, Mines & Processing Centres, Geoscience Australia
  93. "Kennedy Rare-Earth-Elements (REE) Briefing to IAEA, United Nations" via
  94. IAEA: Thorium fuel cycle – Potential benefits and challenges (PDF). pp. 45 (table 8), 97 (ref 78).
  95. Ragheb, M. (12 August 2011) Thorium Resources In Rare Earth Elements.
  96. American Geophysical Union, Fall Meeting 2007, abstract #V33A-1161. Mass and Composition of the Continental Crust
  97. "FFR Chapter 1" (PDF).
  98. Banerjee, S.; Gupta, H. P.; Bhardwaj, S. A. (25 November 2016). "Nuclear power from thorium: different options" (PDF). Current Science . 111 (10): 1607–23. doi:10.18520/cs/v111/i10/1607-1623 . Retrieved 10 March 2018.
  99. Vijayan, P. K.; Basak, A.; Dulera, I. V.; Vaze, K. K.; Basu, S.; Sinha, R. K. (28 August 2015). "Conceptual design of Indian molten salt breeder reactor". Pramana . 85 (3): 539–54. Bibcode:2015Prama..85..539V. doi:10.1007/s12043-015-1070-0. S2CID   117404500.