Nuclear fuels thorium

Nuclear fuel, thorium in, 24 758-759 Nuclear fuel applications, thorium in,... 

The development of thorium-based nuclear power cycles still faces various problems and requires much more R D to be commercialised. As a nuclear fuel, thorium could play a more important role in the coming decades, partly as it is more abundant on Earth than uranium and also because mined thorium has the potential to be used completely in nuclear reactors, compared with the 0.7% of natural uranium. Its future use as a nuclear source of energy will, however, depend greatly on the technological developments currently investigated in various parts of the world and the availability of and access to conventional uranium resources. 

Use Nuclear fuel (thorium-232 is converted to uranium-233 on neutron bombardment after several decay steps), sun lamps, photoelectric cells, target in X-ray tubes, alloys. 

Conversion of thorium nitrate. The conversion consists in producing a thorium nuclear fuel required in power reactors. Five thorium compounds can be used as nuclear fuel thorium metal, thorium dioxide (ThO ), thorium carbide (ThC ), thorium fluoride (ThF,), and thorium chloride (ThClJ. 

The metal is a source of nuclear power. There is probably more energy available for use from thorium in the minerals of the earth s crust than from both uranium and fossil fuels. Any sizable demand from thorium as a nuclear fuel is still several years in the future. Work has been done in developing thorium cycle converter-reactor systems. Several prototypes, including the HTGR (high-temperature gas-cooled reactor) and MSRE (molten salt converter reactor experiment), have operated. While the HTGR reactors are efficient, they are not expected to become important commercially for many years because of certain operating difficulties. 

Several components are required in the practical appHcation of nuclear reactors (1 5). The first and most vital component of a nuclear reactor is the fuel, which is usually uranium slightly enriched in uranium-235 [15117-96-1] to approximately 3%, in contrast to natural uranium which has 0.72% Less commonly, reactors are fueled with plutonium produced by neutron absorption in uranium-238 [24678-82-8]. Even more rare are reactors fueled with uranium-233 [13968-55-3] produced by neutron absorption in thorium-232 (see Nuclear reactors, nuclear fuel reserves). The chemical form of the reactor fuel typically is uranium dioxide, UO2, but uranium metal and other compounds have been used, including sulfates, siUcides, nitrates, carbides, and molten salts. 

The simplest dicarboxylate ligand is oxalate, 020 . Thorium oxalate complexes have been used to produce high density fuel pellets, which improve nuclear fuel processes (73). The stabiUty of oxalate complexes and the relevance to waste disposal have also been studied (74). Many thorium oxalate complexes are known, ranging from the simple Th(C20 2 >5rl2 complex salts such as where n = 4, 5, or 6 and where the counterions... 

Carbides of the Actinides, Uranium, and Thorium. The carbides of uranium and thorium are used as nuclear fuels and breeder materials for gas-cooled, graphite-moderated reactors (see Nuclearreactors). The actinide carbides are prepared by the reaction of metal or metal hydride powders with carbon or preferably by the reduction of the oxides uranium dioxide [1344-57-6] UO2 tduranium octaoxide [1344-59-8], U Og, or thorium... 

Fluidized-bed CVD was developed in the late 1950s for a specific application the coating of nuclear-fuel particles for high temperature gas-cooled reactors. PI The particles are uranium-thorium carbide coated with pyrolytic carbon and silicon carbide for the purpose of containing the products of nuclear fission. The carbon is obtained from the decomposition of propane (C3H8) or propylene... 

Thorium, as well as uranium, can be used as a nuclear fuel. Although not fissile itself, thorium-232 (232Th) can be used as a nuclear fuel through breeding to 233U, which is fissile. Hence, like 238U, it is fertile. 

For many years there has been interest in ntihzing thorium (Th-232) as a nuclear fuel since it is three times as abundant in the Earth s crast as uranium. Also, all of the mined thorium is potentially useable in a reactor, compared with the 0.7% of natural uranium, so some 40 times the amount of energy per unit mass might be available. A thorium reactor would work by having Th-232 capture a neutron to become Th-233 which decays to uranium-233, which fissions. The problem is that insufficient neutrons are generated to keep the reaction going. 

The following is a comparison of thorium with uranium as nuclear fuels ... 

Thorium is the 37th most abundant element found on Earth, and it makes up about 0.0007% of the Earths crust. It is mostly found in the ores of thorite, thorianite (the oxide of thorium), and monazite sand. It is about as abundant as lead in the Earths crust. As a potential fuel for nuclear reactors, thorium has more energy potential than the entire Earths supply of uranium, coal, and gas combined. 

Thorium forms many compounds, including the following example compound Thorium carbide Th + 2C — ThCj. This compound is used as a nuclear fuel. 

Meanwhile AECL and other Canadian departnents and agencies are participating actively in the International Nuclear Fuel Cycle Evaluation (INFCE) to study all fuel cycle options. No decisions on expansion of the present research level on thorium fuels will be taken until information from INFCE has been evaluated by the Canadian Government. 

Thorium is used to make ceramics, lantern mantles, and metals used in the aerospace industry and in nuclear reactions. Thorium can also be used as a fuel for generating nuclear energy. More than 30 years ago thorium oxides were used in hospitals to make certain kinds of diagnostic x-ray photographs. Further information on the properties and uses of thorium can be found in Chapters 3 and 4 of this profile. 

Produces thorlated welding rods Nuclear fuels test quantities Magnesiurn-thorlurn alloys Produces compounds and metals manages DOE thorium stocks... 

Uranium-233, like uranium-235 and plutonium-239, forms a fissionable isotope used as nuclear fuel. This isotope can be made from natural thorium by irradiation with neutrons, as follows ... 

Fuel Element. Any material which may undergo the appropriate reaction and be the source of energy in a fusion or fission nuclear reactor is known as nuclear fuel At the present state of technology such fuels are uranium, thorium or plutonium, either as natural materials or enriched or synthesized isotopes of these elements. They are used as solns or as solids (metals, oxides, or carbonates) shaped as plates, rods etc and known as fuel element (fuel plate or fuel rod)... 

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