How is thorium used

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Resources for News Media. However, as the manufacture requires large amounts of thorium oxide, it is preferred to avoid it, and normally, most gas mantles sold in outdoors equipment shops today are advertised as 'thorium free'. But the next time you stock up for your camping expedition, by all means, bring your Geiger counter! So, short from eating it, there are no particular worries in handling such tiny amounts of thorium oxide.

However, eating it was just the point when using the x-ray contrast agent thorotrast, a state-of-the-art diagnostic aid in the s and s, depending on thorium's excellent ability to absorb x-rays. Undoubtedly, the superior x-ray photographs generated this way saved many lives, so the risk of developing cancer some 20 years later was probably worth taking in serious cases. Thankfully, though, less dangerous contrast agents were soon developed. Thorium may be three times more abundant on Earth than uranium, it is difficult to estimate, and can also be used in nuclear reactors.

In addition, thorium and uranium deposits do not necessarily occur at the same places, thus countries with large potential uranium resources may well have very little thorium and vice-versa. The proponents of this so called thorium fuel cycle also claim it has important technical advantages, but it seems hopes for "burning" weapon grade plutonium or producing waste with reduced risks of nuclear arms proliferation are largely unfounded.

On the contrary, the high melting point of the oxide is a drawback in this application as it makes the preparation of the fuel more difficult. So, although a number of nuclear reactors worldwide have been run on thorium-based fuels the last decades, and some have even been connected to the electrical grid, it may yet be a long time until our houses and streets are again lit up with thorium based technology. So time will tell if Thorium makes its comeback with minimal exposure risks, that is.

In , Lars Nilson isolated the oxide of a new metal from the minerals gadolinite and euxenite. Nilson was a student of the legendary Jacob Berzelius, himself discoverer of many elements. Nilson named this oxide scandia, after Scandinavia. The discovery of this element was especially notable, as, seven years previously, Mendeleev had used his periodic table to predict the existence of ten as yet unknown elements, and for four of these, he predicted in great detail the properties they should have.

One of these four, Mendeleev predicted, should have properties very similar to boron, and he named this new element "ekaboron", meaning "like boron". The metal of this new oxide, scandia, was indeed found to have similar properties to this "ekaboron", thus demonstrating the power of Mendeleev's construct. And join Reading University's David Lindsay to find out what these properties of scandium were that resembled boron so closely, as well as its applications, in next week's Chemistry in its element.

Until then, I'm Meera Senthilingham and thank you for listening. Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists.

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Data W. Haynes, ed. Version 1. Coursey, D. Schwab, J. Tsai, and R. Dragoset, Atomic Weights and Isotopic Compositions version 4. Periodic Table of Videos , accessed December Podcasts Produced by The Naked Scientists.

Download our free Periodic Table app for mobile phones and tablets. Explore all elements. D Dysprosium Dubnium Darmstadtium.

E Europium Erbium Einsteinium. F Fluorine Francium Fermium Flerovium. G Gallium Germanium Gadolinium Gold.

I Iron Indium Iodine Iridium. K Krypton. O Oxygen Osmium Oganesson. U Uranium. V Vanadium. X Xenon. Y Yttrium Ytterbium. Z Zinc Zirconium. Membership Become a member Connect with others Supporting individuals Supporting organisations Manage my membership. Facebook Twitter LinkedIn Youtube. Discovery date. Discovered by.

Origin of the name. Thorium is named after Thor, the Scandinavian god of war. Melting point. Boiling point. Atomic number. Relative atomic mass. Key isotopes. Electron configuration. CAS number. ChemSpider ID. ChemSpider is a free chemical structure database. Electronegativity Pauling scale. Common oxidation states. Atomic mass. Half life. Mode of decay. Relative supply risk. Crustal abundance ppm. Top 3 producers.

Top 3 reserve holders. Political stability of top producer. A third stream of fast reactors to consume actinides from LWRs is planned. The technical difficulty of using molten salts is significantly lower when they do not have the very high activity levels associated with them bearing the dissolved fuels and wastes.

The experience gained with component design, operation, and maintenance with clean salts makes it much easier then to move on and consider the use of liquid fuels, while gaining several key advantages from the ability to operate reactors at low pressure and deliver higher temperatures. Accelerator-driven reactors : A number of groups have investigated how a thorium-fuelled accelerator-driven reactor ADS may work and appear. This reactor operates very close to criticality and therefore requires a relatively small proton beam to drive the spallation neutron source.

Earlier proposals for ADS reactors required high-energy and high-current proton beams which are energy-intensive to produce, and for which operational reliability is a problem.

Kamini is water cooled with a beryllia neutron reflector. The total mass of U in the core is around grams. Aqueous homogeneous reactor : An aqueous homogenous suspension reactor operated over in the Netherlands at 1 MWth using thorium plus HEU oxide pellets.

The thorium-HEU fuel was circulated in solution with continuous reprocessing outside the core to remove fission products, resulting in a high conversion rate to U Thorium fuel cycles offer attractive features, including lower levels of waste generation, less transuranic elements in that waste, and providing a diversification option for nuclear fuel supply.

Also, the use of thorium in most reactor types leads to extra safety margins. Despite these merits, the commercialization of thorium fuels faces some significant hurdles in terms of building an economic case to undertake the necessary development work.

A great deal of testing, analysis and licensing and qualification work is required before any thorium fuel can enter into service. This is expensive and will not eventuate without a clear business case and government support.

Also, uranium is abundant and cheap and forms only a small part of the cost of nuclear electricity generation, so there are no real incentives for investment in a new fuel type that may save uranium resources. Other impediments to the development of thorium fuel cycle are the higher cost of fuel fabrication and the cost of reprocessing to provide the fissile plutonium driver material.

The high cost of fuel fabrication for solid fuel is due partly to the high level of radioactivity that builds up in U chemically separated from the irradiated thorium fuel. Separated U is always contaminated with traces of U which decays with a year half-life to daughter nuclides such as thallium that are high-energy gamma emitters.

Although this confers proliferation resistance to the fuel cycle by making U hard to handle and easy to detect, it results in increased costs.

There are similar problems in recycling thorium itself due to highly radioactive Th an alpha emitter with two-year half life present. Some of these problems are overcome in the LFTR or other molten salt reactor and fuel cycle designs, rather than solid fuel. Particularly in a molten salt reactor, the equilibrium fuel cycle is expected to have relatively low radiotoxicity, being fission products only plus short-lived Pa, without transuranics.

These are continually removed in on-line reprocessing, though this is more complex than for the uranium-plutonium fuel cycle. Nevertheless, the thorium fuel cycle offers energy security benefits in the long-term — due to its potential for being a self-sustaining fuel without the need for fast neutron reactors. It is therefore an important and potentially viable technology that seems able to contribute to building credible, long-term nuclear energy scenarios.

With huge resources of easily-accessible thorium and relatively little uranium, India has made utilization of thorium for large-scale energy production a major goal in its nuclear power programme, utilising a three-stage concept first proposed at the University of Chicago in In all of these stages, used fuel needs to be reprocessed to recover fissile materials for recycling. India is focusing and prioritizing the construction and commissioning of its fleet of MWe sodium-cooled fast reactors in which it will breed the required plutonium which is the key to unlocking the energy potential of thorium in its advanced heavy water reactors.

This will take another years, and so it will still be some time before India is using thorium energy to any extent.

The MWe prototype FBR under construction in Kalpakkam was expected to start up in , but is now the target date. In , despite the relaxation of trade restrictions on uranium, India reaffirmed its intention to proceed with developing the thorium cycle. The thorium fuel cycle is sometimes promoted as having excellent non-proliferation credentials. This is true, but some history and physics bears noting. It is possible to use U in a nuclear weapon, and in the USA detonated a device with a plutonium-U composite pit, in Operation Teapot.

The explosive yield was less than anticipated, at 22 kilotons. In India detonated a very small device based on U called Shakti V. However, the production of U inevitably also yields U which is a strong gamma-emitter, as are some decay products such as thallium 'thorium C' , making the material extremely difficult to handle and also easy to detect.

Neutron absorption by Th produces Th which beta-decays with a half-life of about 22 minutes to protactinium Pa — and this decays to U by further beta decay with a half-life of 27 days. Some of the bred-in U is converted to U by further neutron absorption. U is an unwanted parasitic neutron absorber. It converts to fissile U the naturally occuring fissile isotope of uranium and this somewhat compensates for this neutronic penalty. In fuel cycles involving the multi-recycle of thorium-U fuels, the build up of U can be appreciable.

A U nucleus yields more neutrons, on average, when it fissions splits than either a uranium or plutonium nucleus. In other words, for every thermal neutron absorbed in a U fuel there are a greater number of neutrons produced and released into the surrounding fuel.

This gives better neutron economy in the reactor system.. Neutron moderation is tailored by the amount of graphite in the core aiming for an epithermal spectrum. This uranium can be selectively removed as uranium hexafluoride UF6 by bubbling fluorine gas through the salt. After conversion it can be directed to the core as fissile fuel.

Spallation is the process where nucleons are ejected from a heavy nucleus being hit by a high energy particle.

In this case, a high-enery proton beam directed at a heavy target expels a number of spallation particles, including neutrons. The core of the Shippingport demonstration LWBR consisted of an array of seed and blanket modules surrounded by an outer reflector region. The reflector region contained only thorium oxide at the beginning of the core life. Together, the seed and blanket have the same geometry as a normal VVER fuel assembly rods in a hexagonal array mm wide.

The molten salt in the core circuit consists of lithium, beryllium and fissile U fluorides FLiBe with uranium. Most fission products dissolve or suspend in the salt and some of these are removed progressively in an adjacent on-line radiochemical processing unit.

Actinides are less-readily formed than in fuel with atomic mass greater than The blanket circuit contains a significant amount of thorium tetrafluoride in the molten Li-Be fluoride salt. Newly-formed U forms soluble uranium tetrafluoride UF 4 , which is converted to gaseous uranium hexafluoride UF 6 by bubbling fluorine gas through the salt which does not chemically affect the less-reactive thorium tetrafluoride.

The volatile uranium hexafluoride is captured, reduced back to soluble UF 4 by hydrogen gas, and finally is directed to the core to serve as fissile fuel. Protactinium — a neutron absorber — is not a major problem in the blanket salt. Babyak, L. Freeman, H. Yu, K, Wang, R. Galperin, A. Radkowsky and M. Thorium Updated November Thorium is more abundant in nature than uranium. It is fertile rather than fissile, and can only be used as a fuel in conjunction with a fissile material such as recycled plutonium.

Thorium fuels can breed fissile uranium to be used in various kinds of nuclear reactors. Molten salt reactors are well suited to thorium fuel, as normal fuel fabrication is avoided.