Thorium resources are the estimated mineral reserves of thorium on Earth. Thorium is a future potential source of low-carbon energy. [1] Thorium has been demonstrated to perform as a nuclear fuel in several reactor designs. [2] [3] It is present with a higher abundance than uranium in the crust of the earth. Thorium resources have not been estimated and assessed with a higher level of confidence, as in the case of uranium. Approximately 6 million tonnes of thorium have been estimated globally based on currently limited exploration and mainly on historical data. [4] [5]
Thorium resources are found widely in over 35 countries all over the world. As there is currently negligible commercial use of thorium, the resources should be considered potentially viable according to the United Nations Framework Classification for Resources. Figures are given in metric tonnes of thorium metal.
Country | Total thorium resources, tonnes Th (rounded) | Remarks |
---|---|---|
Angola | 10,000 | Historical data [6] |
Argentina | 35,910 | Recent reassessment [7] |
Australia | 595,000 | [8] |
Brazil | 632,000 | [9] |
Canada | 172,000 | [10] |
China | 100,000 | Possibly many hundred thousand tonnes. [11] |
Congo, Democratic Republic of | 2,500 | [6] |
Egypt | 380,000 | Historical data [12] |
Finland | 60,000 | Historical data [13] |
France | 1,000 | Historical data. Estimated to be from several hundred to a thousand tonnes. [14] |
Greenland (Denmark) | 86,000 | Current active exploration. Possibly up to 684,000 t. [15] |
India | 846,477 | [16] |
Iran | 30,000 | Historical data [17] |
Kenya | 8,000 | Historical data [12] |
Kazakhstan | 50,000 | [18] |
Korea, Republic of | 6,000 | [19] |
Madagascar | 22,000 | Historical data [20] |
Malawi | 9,000 | Historical data [21] |
Malaysia | 18,000 | [22] |
Morocco | 30,000 | Historical data [21] |
Mozambique | 10,000 | [23] |
Nigeria | 29,000 | [23] |
Norway | 87,000 | Historical data [24] |
Peru | 20,000 | [25] |
Russia | 155,000 | [26] [27] |
South Africa | 148,000 | [28] |
Sri Lanka | 4,000 | [27] |
Sweden | 50,000 | Historical data [29] |
Taiwan | 9,000 | [18] |
Thailand | 10,000 | Historical data [30] |
Turkey | 381,000 | Historical data [31] |
United States of America | 595,000 | [32] |
Uruguay | 3,000 | Historical data [25] |
Uzbekistan | 5,000 | [33] |
Venezuela | 300,000 | Historical data [25] |
Vietnam | 5,000 | [33] |
Others (Africa) | 1,000 | Historical data [18] |
Others (CIS) (excluding Russia, Kazakhstan and Uzbekistan) | 1,340,000 | [18] |
Total | 6,245,887 |
Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced by nuclear fission of uranium and plutonium in nuclear power plants. Nuclear decay processes are used in niche applications such as radioisotope thermoelectric generators in some space probes such as Voyager 2. Generating electricity from fusion power remains the focus of international research.
Thorium is a chemical element. It has the symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive gray when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided.
Nuclear engineering is the engineering discipline concerned with designing and applying systems that utilize the energy released by nuclear processes. The most prominent application of nuclear engineering is the generation of electricity. Worldwide, some 440 nuclear reactors in 32 countries generate 10 percent of the world's energy through nuclear fission. In the future, it is expected that nuclear fusion will add another nuclear means of generating energy. Both reactions make use of the nuclear binding energy released when atomic nucleons are either separated (fission) or brought together (fusion). The energy available is given by the binding energy curve, and the amount generated is much greater than that generated through chemical reactions. Fission of 1 gram of uranium yields as much energy as burning 3 tons of coal or 600 gallons of fuel oil, without adding carbon dioxide to the atmosphere.
Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, nuclear decommissioning, rare-earth mining, and nuclear weapons reprocessing. The storage and disposal of radioactive waste is regulated by government agencies in order to protect human health and the environment.
A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. These reactors can be fueled with more-commonly available isotopes of uranium and thorium, such as uranium-238 and thorium-232, as opposed to the rare uranium-235 which is used in conventional reactors. These materials are called fertile materials since they can be bred into fuel by these breeder reactors.
A nuclear fuel bank is reserve of low enriched uranium (LEU) for countries that need a backup source of LEU to fuel their nuclear reactors. Countries that do have enrichment technology would donate enriched fuel to a "bank", from which countries not possessing enrichment technology would obtain fuel for their power reactors.
Nuclear power in Canada is provided by 19 commercial reactors with a net capacity of 13.5 gigawatt (GW), producing a total of 95.6 terawatt-hours (TWh) of electricity, which accounted for 16.6% of the country's total electric energy generation in 2015. All but one of these reactors are located in Ontario, where they produced 61% of the province's electricity in 2019. Seven smaller reactors are used for research and to produce radiopharmaceuticals for use in nuclear medicine.
The thorium fuel cycle is a nuclear fuel cycle that uses an isotope of thorium, 232
Th
, as the fertile material. In the reactor, 232
Th
is transmuted into the fissile artificial uranium isotope 233
U
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
Th
absorbs neutrons to produce 233
U
. This parallels the process in uranium breeder reactors whereby fertile 238
U
absorbs neutrons to form fissile 239
Pu
. Depending on the design of the reactor and fuel cycle, the generated 233
U
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 was supposed to be built starting with a 300 MWe prototype in 2016.
Uranium mining is the process of extraction of uranium ore from the ground. Over 50 thousand tons of uranium were produced in 2019. Kazakhstan, Canada, and Australia were the top three uranium producers, respectively, and together account for 68% of world production. Other countries producing more than 1,000 tons per year included Namibia, Niger, Russia, Uzbekistan, the United States, and China. Nearly all of the world's mined uranium is used to power nuclear power plants. Historically uranium was also used in applications such as uranium glass or ferrouranium but those applications have declined due to the radioactivity of uranium and are nowadays mostly supplied with a plentiful cheap supply of depleted uranium which is also used in uranium ammunition. In addition to being cheaper, depleted uranium is also less radioactive due to a lower content of short-lived 234
U and 235
U than natural uranium.
China is one of the world's largest producers of nuclear power. The country ranks third in the world both in total nuclear power capacity installed and electricity generated, accounting for around one tenth of global nuclear power generated. As of February 2023, China has 55 plants with 57GW in operation, 22 under construction with 24 GW and more than 70 planned with 88GW. About 5% of electricity in the country is due to nuclear energy. These plants generated 417 TWh of electricity in 2022 This is versus the September 2022 numbers of 53 nuclear reactors, with a total capacity of 55.6 gigawatt (GW). In 2019, nuclear power had contributed 4.9% of the total Chinese electricity production, with 348.1 TWh.
Nuclear power is the fifth-largest source of electricity in India after coal, gas, hydroelectricity and wind power. As of November 2020, India has 23 nuclear reactors in operation in 8 nuclear power plants, with a total installed capacity of 7,380 MW. Nuclear power produced a total of 43 TWh in 2020–21, contributing 3.11% of total power generation in India. 10 more reactors are under construction with a combined generation capacity of 8,000 MW.
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 India 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.
Integrated Nuclear Fuel Cycle Information System (iNFCIS) is a set of databases related to the nuclear fuel cycle maintained by the International Atomic Energy Agency (IAEA). The main objective of iNFCIS is to provide information on all aspects of nuclear fuel cycle to various researchers, analysts, energy planners, academicians, students and the general public. Presently iNFCIS includes several modules. iNFCIS requires free registration for on-line access.
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—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 that is bred in the reactor. Plutonium-239 is produced at much lower levels and can be consumed in thorium reactors.
Thorium is found in small amounts in most rocks and soils. Soil commonly contains an average of around 6 parts per million (ppm) of thorium. Thorium occurs in several minerals including thorite (ThSiO4), thorianite (ThO2 + UO2) and monazite. Thorianite is a rare mineral and may contain up to about 12% thorium oxide. Monazite contains 2.5% thorium, allanite has 0.1 to 2% thorium and zircon can have up to 0.4% thorium. Thorium-containing minerals occur on all continents. Thorium is several times more abundant in Earth's crust than all isotopes of uranium combined and thorium-232 is several hundred times more abundant than uranium-235.
Chaitanyamoy Ganguly is an Indian nuclear scientist and a former head of the Nuclear Fuel Cycle and Materials Section of the International Atomic Energy Agency (IAEA), credited with many innovations in the field of nuclear material science. He was honored by the government of India in 2002, with the fourth-highest Indian civilian award of Padma Shri.
Copenhagen Atomics is a Danish molten salt technology company developing mass manufacturable molten-salt reactors. The company is pursuing small modular, molten fuel salt, thorium fuel cycle, thermal spectrum, breeder reactors using separated plutonium from spent nuclear fuel as the initial fissile load for the first generation of reactors.
Depleted uranium hexafluoride (DUHF; also referred to as depleted uranium tails, depleted uranium tailings or DUF6) is a byproduct of the processing of uranium hexafluoride into enriched uranium. It is one of the chemical forms of depleted uranium (up to 73-75%), along with depleted triuranium octoxide (up to 25%) and depleted uranium metal (up to 2%). DUHF is 1.7 times less radioactive than uranium hexafluoride and natural uranium.