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March, 2011:


March 2011

Thorium continues to be a tanatalising possibility for use in nuclear power reactors, though for many years India has been the only sponsor of major research efforts to use it. Other endeavours include the development of the Radkowsky Thorium Reactor concept being carried out by US company Thorium Power (now Lightbridge Corporation) with Russian collaboration.

In mid-2009, AECL signed agreements with three Chinese entities to develop and demonstrate the use of thorium fuel in the Candu reactors at Qinshan in China. Another mid-2009 agreement, between Areva and Lightbridge Corporation, was for assessing the use of thorium fuel in Areva’s EPR, drawing upon earlier research. Thorium can also be used in Generation IV and other advanced nuclear fuel cycle systems.

Nature and sources of thorium

Thorium is a naturally-occurring, slightly radioactive metal discovered in 1828 by the Swedish chemist Jons Jakob Berzelius, who named it after Thor, the Norse god of thunder. It is found in small amounts in most rocks and soils, where it is about three times more abundant than uranium. Soil commonly contains an average of around 6 parts per million (ppm) of thorium.

Thorium-232 (Th-232) decays very slowly (its half-life is about three times the age of the Earth) but other thorium isotopes occur in its and in uranium’s decay chains. Most of these are short-lived and hence much more radioactive than Th-232, though on a mass basis they are negligible.

When pure, thorium is a silvery white metal that retains its lustre for several months. However, when it is contaminated with the oxide, thorium slowly tarnishes in air, becoming grey and eventually black. Thorium oxide (ThO2), also called thoria, has one of the highest melting points of all oxides (3300°C). When heated in air, thorium metal turnings ignite and burn brilliantly with a white light. Because of these properties, thorium has found applications in light bulb elements, lantern mantles, arc-light lamps, welding electrodes and heat-resistant ceramics. Glass containing thorium oxide has a high refractive index and dispersion and is used in high quality lenses for cameras and scientific instruments.

The most common source of thorium is the rare earth phosphate mineral, monazite, which contains up to about 12% thorium phosphate, but 6-7% on average. Monazite is found in igneous and other rocks but the richest concentrations are in placer deposits, concentrated by wave and current action with other heavy minerals. World monazite resources are estimated to be about 12 million tonnes, 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 below). Thorium recovery from monazite usually involves leaching with sodium hydroxide at 140°C followed by a complex process to precipitate pure ThO2.

Thorite (ThSiO4) is another common mineral. A large vein deposit of thorium and rare earth metals is in Idaho.

The 2007 IAEA-NEA publication Uranium 2007: Resources, Production and Demand (often referred to as the ‘Red Book’) gives a figure of 4.4 million tonnes of total known and estimated resources, but this excludes data from much of the world. Data for reasonably assured and inferred resources recoverable at a cost of $80/kg Th or less are given in the table below. Some of the figures are based on assumptions and surrogate data for mineral sands, not direct geological data in the same way as most mineral resources.

(Reasonably assured and inferred resources recoverable at
up to $80/kg Th)
Country Tonnes % of total
Australia 489,000 19
USA 400,000 15
Turkey 344,000 13
India 319,000 12
Venezuela 300,000 12
Brazil 302,000 12
Norway 132,000 5
Egypt 100,000 4
Russia 75,000 3
Greenland 54,000 2
Canada 44,000 2
South Africa 18,000 1
Other countries 33,000 1
World total


Thorium as a nuclear fuel

Thorium, as well as uranium, can be used as a nuclear fuel. Although not fissile itself, Th-232 will absorb slow neutrons to produce uranium-233 (U-233)a, which is fissile (and long-lived). The irradiated fuel can then be unloaded from the reactor, the U-233 separated from the thorium, and fed back into another reactor as part of a closed fuel cycle. Alternatively, U-233 can be bred from thorium in a blanket, the U-233 separated, and then fed into the core.

In one significant respect U-233 is better than uranium-235 and plutonium-239, because of its higher neutron yield per neutron absorbed. Given a start with some other fissile material (U-233, U-235 or Pu-239) as a driver, a breeding cycle similar to but more efficient than that with U-238 and plutonium (in normal, slow neutron reactors) can be set up. (The driver fuels provide all the neutrons initially, but are progressively supplemented by U-233 as it forms from the thorium.) However, there are also features of the neutron economy which counter this advantage. In particular the intermediate product protactinium-233 (Pa-233) is a neutron absorber which diminishes U-233 yield.

Over the last 40 years there has been interest in utilising thorium as a nuclear fuel since it is more abundant in the Earth’s crust than uranium. Also, all of the mined thorium is potentially useable in a reactor, compared with the 0.7% of natural uranium in today’s reactorsb, so some 40 times the amount of energy per unit mass might theoretically be available (without recourse to fast neutron reactors). But this relative advantage vanishes if fast neutron reactors are used for uranium.

Thorium R&D history

The use of thorium-based fuel cycles has been studied for about 40 years, but on a much smaller scale than uranium or uranium/plutonium cycles. Basic research and development has been conducted in Germany, India, Japan, Russia, the UK and the USA. Test reactor irradiation of thorium fuel to high burn-ups has also been conducted and several test reactors have either been partially or completely loaded with thorium-based fuel.

Noteworthy experiments involving thorium fuel include the following, the first three being high-temperature gas-cooled reactors:

  • Between 1967 and 1988, the AVR (Atom Versuchs Reaktor, Nuclear Test Reactor) experimental pebble bed reactor at Jülich, Germany, operated for over 750 weeks at 15 MWe, about 95% of the time with thorium-based fuel. The fuel used consisted of about 100,000 billiard ball-sized fuel elements. Overall a total of 1360 kg of thorium was used, mixed with high-enriched uranium (HEU). Burn-ups of 150,000 MWd/t were achieved.
  • Thorium fuel elements with a 10:1 Th/U (HEU) ratio were irradiated in the 20 MWth Dragon reactor at Winfrith, UK, for 741 full power days. Dragon was run as an OECD/Euratom cooperation project, involving Austria, Denmark, Sweden, Norway and Switzerland in addition to the UK, from 1964 to 1973. The Th/U fuel was used to ‘breed and feed’, so that the U-233 formed replaced the U-235 at about the same rate, and fuel could be left in the reactor for about six years.
  • General Atomics’ Peach Bottom high-temperature, graphite-moderated, helium-cooled reactor in the USA operated between 1967 and 1974 at 110 MWth, using high-enriched uranium with thorium.
  • In Canada, AECL has more than 50 years experience with thorium-based fuels, including burn-up to 47 GWd/t. Some 25 tests were performed to 1987 in three research reactors and one pre-commercial reactor (NPD), with fuels ranging from ThO2 to that with 30% UO2, though most were with 1-3% UO2, the U being high-enriched.
  • In India, the Kamini 30 kWth experimental neutron-source research reactor using U-233, recovered from ThO2 fuel irradiated in another reactor, started up in 1996 near Kalpakkam. The reactor was built adjacent to the 40 MWt Fast Breeder Test Reactor, in which the ThO2 is irradiated.
  • In the Netherlands, an aqueous homogenous suspension reactor operated at 1MWth for three years in the mid-1970s. The HEU/Th fuel was circulated in solution and reprocessing occurred continuously to remove fission products, resulting in a high conversion rate to U-233.

There have also been several experiments with fast neutron reactors.

Power reactors

Much experience has been gained in thorium-based fuel in power reactors around the world, some using high-enriched uranium (HEU) as the main fuel:

  • The 300 MWe THTR (Thorium High Temperature Reactor) reactor in Germany was developed from the AVR and operated between 1983 and 1989 with 674,000 pebbles, over half containing Th/HEU fuel (the rest graphite moderator and some neutron absorbers). These were continuously recycled on load and on average the fuel passed six times through the core.
  • The Fort St Vrain reactor was the only commercial thorium-fuelled nuclear plant in the USA, also developed from the AVR in Germany, and operated 1976-1989. It was a high-temperature (700°C), graphite-moderated, helium-cooled reactor with a Th/HEU fuel designed to operate at 842 MWth (330 MWe). The fuel was in microspheres of thorium carbide and Th/U-235 carbide coated with silicon oxide and pyrolytic carbon to retain fission products. It was arranged in hexagonal columns (‘prisms’) rather than as pebbles. Almost 25 tonnes of thorium was used in fuel for the reactor, and this achieved 170,000 MWd/t burn-up.
  • Thorium-based fuel for PWRs was investigated at the Shippingport reactor in the USA (discussed in the section below on the Light Water Breeder Reactor).
  • In India, thorium has been used for power flattening in the initial cores of the two Kakrapar pressurised heavy water reactors (PHWRs).
  • The 60 MWe Lingen Boiling Water Reactor (BWR) in Germany utilised Th/Pu-based fuel test elements.

Light Water Breeder Reactor

The Light Water Breeder Reactor (LWBR) concept is a major potential application for conventional pressurised water reactors (PWRs) and was successfully demonstrated at the Shippingport reactor in the USA2. Shippingport commenced commercial operation in December 1957 as the first large-scale nuclear power reactor to be operated solely for electricity production. In 1965 the Atomic Energy Commission began designing a uranium-233/thorium core for the reactor and in 1976, the Energy Research and Development Administration (now the Department of Energy) established the Advanced Water Breeder Applications programme to evaluate the LWBR concept for commercial-scale applications. Shippingport operated as an LWBR between August 1977 and October 1982, when the station was finally shut down. During this period, the demonstration LWBR operated for over 29,000 effective full power hours with an availability factor of 76% and had a gross electrical output of over 2.1 billion kilowatt hours. Following operation, inspection of the core found that 1.39% more fissile fuel was present at the end of core life than at the beginning, proving that breeding had occurred.

The core of the Shippingport demonstration LWBR consisted of an array of seed and blanket modules surrounded by an outer reflector region. In the seed and blanket regions, the fuel pellets contained a mixture of thorium-232 oxide (ThO2) and uranium oxide (UO2) that was over 98% enriched in U-233. The proportion by weight of UO2 was around 5-6% in the seed region, and about 1.5-3% in the blanket region. The reflector region contained only thorium oxide at the beginning of the core life. U-233 was used because at the time it was believed that U-235 would not release enough neutrons per fission and Pu-239 would parasitically capture too many neutrons to allow breeding in a PWR.

Current thorium fuel cycle research

Several advanced reactors concepts are currently being developed, including:

  • High-temperature gas-cooled reactors (HTGRs) of two kinds: pebble bed and with prismatic fuel elements. The Gas Turbine-Modular Helium Reactor (GT-MHR) being developed by General Atomics uses a prismatic fuel and builds on US experience, particularly from the Fort St Vrain reactor. The GT-MHR core can accommodate a wide range of fuel options, including HEU/Th, U-233/Th and Pu/Th. Pebble bed reactor development builds on German work with the AVR and THTR and is under development in China and South Africac. A pebble bed reactor can potentially use thorium in its fuel pebbles.
  • The Radkowsky Thorium Reactor builds on the seed-blanket arrangement of the LWBR concept. (see subsection below)
  • The molten salt reactor (MSR) is an advanced breeder concept, in which the coolant is a molten salt, usually a fluoride salt mixture. This is hot, but not under pressure, and does not boil below about 1400°C. Much research has focused on lithium and beryllium additions to the salt mixture. The fuel can be dissolved enriched uranium, thorium or U-233 fluorides, and recent discussion has been on the Liquid Fluoride Thorium Reactor, utilizing U-233 which has been bred in a liquid thorium salt blanket and continuously removed to be added to the core. The MSR was studied in depth in the 1960s, but is now being revived because of the availability of advanced technology for the materials and components. There is now renewed interest in the MSR concept in China, Japan, Russia, France and the USA, and one of the six Generation IV designs selected for further development is the MSR (see also subsection below and information page on Generation IV Nuclear Reactors).
  • CANDU-type reactors – AECL is researching the thorium fuel cycle application to Enhanced Candu 6 and ACR-1000 reactors with 5% plutonium (reactor grade) plus thorium. In the closed fuel cycle, the driver fuel required for starting off is progressively replaced with recycled U-233, so that on reaching equilibrium 80% of the energy comes from thorium. Fissile drive fuel could be LEU, plutonium, or recycled uranium from LWR. AECL envisages fleets of CANDU reactors with near-self-sufficient equilibrium thorium (SSET) fuel cycles and a few fast breeder reactors to provide plutonium. AECL is also working closely with Third Qinshan Nuclear Power Company (TQNPC), China North Nuclear Fuel Corporation and Nuclear Power Institute of China (NPIC) at Chengdu to develop and demonstrate the use of thorium fuel and to study the commercial and technical feasibility of its full-scale use in Candu units such as at Qinshan. (see also Th in PHWR subsection of R&D section in China Fuel Cycle paper)
  • Advanced heavy water reactor (AHWR) – India is working on this and, like the Canadian ACR design, the 300 MWe AHWR design is light water cooled. The main part of the core is subcritical with Th/U-233 oxide and Th/Pu-239 oxide, mixed so that the system is self-sustaining in U-233. The initial core will be entirely Th-Pu-239 oxide fuel assemblies, but as U-233 is available, 30 of the fuel pins in each assembly will be Th-U-233 oxide, arranged in concentric rings. It is designed for 100-year plant life and is expected to utilise 65% of the energy of the fuel. About 75% of the power will come from the thorium.
  • Fast breeder reactor (FBRs), along with the AHWRs, play an essential role in India’s three-stage nuclear power programme (see section on India’s plans for thorium cycle below). A 500 MWe prototype FBR under construction in Kalpakkam is designed to breed U-233 from thorium.

Radkowsky Thorium Reactor

The work at Shippingport (see section above on the Light Water Breeder Reactor) was developed by Alvin Radkowsky, who was the chief scientist of the United States Navy’s nuclear propulsion programme from 1950 to 1972 and headed the team that built the Shippingport plant. The Radkowsky Thorium Reactor (RTR) addresses the aspects of the thorium fuel cycle that are considered sensitive from the point of view of weapons proliferation. In particular the RTR avoids the need to separate U-233.

Radkowsky proposed the use of a heterogenous seed-blanket fuel assembly geometry, which separates the uranium (or plutonium) part of the fuel (the seed) from the thorium part of the fuel (the blanket). In the blanket part, U-233 is generated and fissioned, while the seed part supplies neutrons to the blanket. Either uranium enriched to 20% U-235 or plutonium can be used in the seed region3. One method of increasing the proliferation resistance of the design is to include some U-238 in the thorium blanket. Any uranium chemically separated from it (for the U-233 ) would not be useable for weapons. Used blanket fuel would also contain U-232, which decays rapidly and has very gamma-active daughters creating significant problems in handling the bred U-233 and hence conferring proliferation resistance. Plutonium produced in the seed will have a high proportion of Pu-238, generating a lot of heat and making it even more unsuitable for weapons than normal reactor-grade plutonium. Radkowsky’s designs are currently being developed by Thorium Power (now Lightbridge Corporation)d, based in McLean, Virginia.

Since 1994, Thorium Power Ltd has been involved in a Russian programme to develop a thorium-uranium fuel, which more recently has moved to have a particular emphasis on utilization of weapons-grade plutonium in a thorium-plutonium fuel. The program is based at Moscow’s Kurchatov Institute and receives US government funding to design fuel for Russian VVER-1000 reactors. The design has a demountable centre portion and blanket arrangement, with the plutonium in the centre and the thorium (with uranium) around ite. The blanket material remains in the reactor for nine years but the centre portion is burned for only three years (as in a normal VVER). Design of the seed fuel rods in the centre portion draws on extensive experience of Russian navy reactors.

The thorium-plutonium fuel claims four advantages over the use of mixed uranium-plutonium oxide (MOX) fuel: increased proliferation resistance; compatibility with existing reactors – which will need minimal modification to be able to burn it; the fuel can be made in existing plants in Russia; and a lot more plutonium can be put into a single fuel assembly than with MOX fuel, so that three times as much can be disposed of as when using MOX. The used fuel amounts to about half the volume of MOX and is even less likely to allow recovery of weapons-useable material than used MOX fuel, since less fissile plutonium remains in it. With an estimated 150 tonnes of surplus weapons plutonium in Russia, the thorium-plutonium project would not necessarily cut across existing plans to make MOX fuel.

Liquid Fluoride Thorium Reactor

A quite different concept is the Liquid Fluoride Thorium Reactor (LFTR), utilizing U-233 which has been bred in a liquid thorium salt blanket.

The core consists of fissile U-233 tetrafluoride in molten fluoride salts of lithium and beryllium at some 700°C and at low pressure within a graphite structure that serves as a moderator and neutron reflector. Fission products dissolve in the salt and are removed progressively – xenon bubbles out, others are captured chemically. Actinides are less-readily formed than in fuel with atomic mass >235, and those that do form stay in the fuel until they are transmuted and eventually fissioned.

The blanket contains a mixture of thorium tetrafluoride in a fluoride salt containing lithium and beryllium, made molten by the heat of the core. Newly-formed U-233 forms soluble uranium tetrafluoride (UF4), which is converted to gaseous uranium hexafluoride (UF6) by bubbling fluorine gas through the blanket solution (which does not chemically affect the less-reactive thorium tetrafluoride). Uranium hexafluoride comes out of solution, is captured, then is reduced back to soluble UF4 by hydrogen gas in a reduction column, and finally is directed to the core to serve as fissile fuel.

The LFTR is not a fast reactor, but with some moderation by the graphite is epithermal (intermediate neutron speed). Safety is achieved with a freeze plug which if power is cut allows the fuel to drain into subcritical geometry in a catch basin. There is also a negative temperature coefficient of reactivity due to expansion of the fuel.

The China Academy of Sciences in January 2011 launched an R&D program on LFTR, known there as the thorium-breeding molten-salt reactor (Th-MSR or TMSR), and claimed to have the world’s largest national effort on it, hoping to obtain full intellectual property rights on the technology.

India’s plans for thorium cycle

With about six times more thorium than 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:

  • Pressurised heavy water reactors (PHWRs) fuelled by natural uranium, plus light water reactors, producing plutonium.
  • Fast breeder reactors (FBRs) using plutonium-based fuel to breed U-233 from thorium. The blanket around the core will have uranium as well as thorium, so that further plutonium (particularly Pu-239) is produced as well as the U-233.
  • Advanced heavy water reactors burn the U-233 and this plutonium with thorium, getting about 75% of their power from the thorium. The used fuel will then be reprocessed to recover fissile materials for recycling.

This Indian programme has moved from aiming to be sustained simply with thorium to one ‘driven’ with the addition of further fissile uranium and plutonium, to give greater efficiency. In 2009, despite the relaxation of trade restrictions on uranium, India reaffirmed its intention to proceed with developing the thorium cycle.

Another option for the third stage, while continuing with the PHWR and FBR stages, is the use of subcritical accelerator driven systems.

Thorium and accelerator driven systems

In an accelerator driven system (ADS), high-energy neutrons are produced through the spallationf reaction of high-energy protons from an accelerator striking heavy target nuclei (lead, lead-bismuth or other material). These neutrons can be directed to a subcritical reactor containing thorium, where the neutrons breed U-233 and promote the fission of it. There is therefore the possibility of sustaining a fission reaction which can readily be turned off, and used either for power generation or destruction of actinides resulting from the U/Pu fuel cycle. The use of thorium instead of uranium reduces the quantity of actinides that are produced. (See also information page on Accelerator-Driven Nuclear Energy.)

Developing a thorium-based fuel cycle

Despite the thorium fuel cycle having a number of attractive features, development has always run into difficulties.

The main attractive features are:

  • The possibility of utilising a very abundant resource which has hitherto been of so little interest that it has never been quantified properly.
  • The production of power with few long-lived transuranic elements in the waste.
  • Reduced radioactive wastes generally.

The problems include:

  • The high cost of fuel fabrication, due partly to the high radioactivity of U-233 chemically separated from the irradiated thorium fuel. Separated U-233 is always contaminated with traces of U-232 (69 year half-life but whose daughter products such as thallium-208 are strong gamma emitters with very short half-lives). Although this confers proliferation resistance to the fuel cycle by making U-233 hard to handle and easy to detect, it results in increased costs.
  • The similar problems in recycling thorium itself due to highly radioactive Th-228 (an alpha emitter with two-year half life) present.
  • Some concern over weapons proliferation risk of U-233 (if it could be separated on its own), although many designs such as the Radkowsky Thorium Reactor address this concern.
  • The technical problems (not yet satisfactorily solved) in reprocessing solid fuels. However, with some designs, in particular the molten salt reactor (MSR), these problems are likely to largely disappear.

Much development work is still required before the thorium fuel cycle can be commercialised, and the effort required seems unlikely while (or where) abundant uranium is available. In this respect, recent international moves to bring India into the ambit of international trade might result in the country ceasing to persist with the thorium cycle, as it now has ready access to traded uranium and conventional reactor designs.

Nevertheless, the thorium fuel cycle, with its potential for breeding fuel without the need for fast neutron reactors, holds considerable potential in the long-term. It is a significant factor in the long-term sustainability of nuclear energy.

Unclear On Nuclear? Try Thorium – Nuclear Energy Without The Side Effects

HomeInventor  Inventor Spot   23 March 2011

If the current events in Japan have demonstrated one thing, it’s that nuclear energy in its current form is not safe. Put simply, if the Japanese can’t do it right with their impeccable approach to workmanship, then heaven help the rest of us.

But nuclear energy produces about 13,000 times the amount of energy per pound of fuel than coal, and considerably less waste. The only problem with the waste, of course, is that uranium and plutonium produce immeasurably more dangerous waste than coal, or oil, or natural gas, or any other energy source currently in widespread use: not only does it need to be stored safely for thousands of years (like that’s going to happen), but if it gets in the wrong hands, well, use your imagination.

With so many unknowns surrounding nuclear power – the impossibility of 100% safe operation; the unlikeliness of ensuring safe storage of nuclear waste across millennia; the probability of some of that waste ending up in the hands of terrorists or rogue states – you could justifiably be wondering why there are nearly 450 nuclear power stations operating around the world, with a further 65 under construction.

You could especially be wondering why, if you knew that a way to process a much safer form of nuclear energy has been available for nearly the last half a century. And then if you discovered that the source of this energy was four times more abundant than uranium (which contains all the plutonium), you could well be vigorously shaking and slapping your head simultaneously.

Don’t do it to yourself! Even if it is true that thorium possesses all these properties.

The primary advantage of thorium is probably safety. As reported recently in The Telegraph, thorium expert Kirk Sorensen claims that, “If it begins to overheat, a little plug melts and the salts drain into a pan. There is no need for computers, or the sort of electrical pumps that were crippled by the tsunami. The reactor saves itself. They operate at atmospheric pressure so you don’t have the sort of hydrogen explosions we’ve seen in Japan. One of these reactors would have come through the tsunami just fine. There would have been no radiation release.” This is largely because thorium is not fissile: it cannot sustain a nuclear chain reaction without a catalyst.

But that’s not all. Because thorium is lighter than uranium (which is lighter than plutonium), it doesn’t produce as many heavy, radioactive byproducts. It produces considerably less waste than its heavier cousins, and that is waste that only needs to be managed for 500 years – still a long time, but nowhere near the 10,000 years that some existing nuclear waste requires. That’s if you want to store it. Alternatively, you could add a bit of plutonium to the mix, and you’d burn it all up as part of the energy creation process. That’s right: handled properly, a thorium reactor produces no radioactive waste.

Oh, and thorium comes out of the ground as 100% thorium. It doesn’t need to be enriched, like uranium, which contains less than 1% fissionable material. So, while there is around four times as much thorium in the ground as uranium, there is closer to 6,000 times more usable thorium than usable uranium.

In the USA, which possesses the world’s largest thorium reserves, an experimental thorium reactor was built at the Oak Ridge National Laboratory in Tennessee back in the ’60s, operating for around five years before its funding was cut. Today, there is an operating thorium reactor in India, and plans for them in China, Russia and Norway.

Liquid Fluoride Thorium Reactor

A quite different concept is the Liquid Fluoride Thorium Reactor (LFTR), utilizing U-233 which has been bred in a liquid thorium salt blanket.

The core consists of fissile U-233 tetrafluoride in molten fluoride salts of lithium and beryllium at some 700°C and at low pressure within a graphite structure that serves as a moderator and neutron reflector. Fission products dissolve in the salt and are removed progressively – xenon bubbles out, others are captured chemically. Actinides are less-readily formed than in fuel with atomic mass >235, and those that do form stay in the fuel until they are transmuted and eventually fissioned.

The blanket contains a mixture of thorium tetrafluoride in a fluoride salt containing lithium and beryllium, made molten by the heat of the core. Newly-formed U-233 forms soluble uranium tetrafluoride (UF4), which is converted to gaseous uranium hexafluoride (UF6) by bubbling fluorine gas through the blanket solution (which does not chemically affect the less-reactive thorium tetrafluoride). Uranium hexafluoride comes out of solution, is captured, then is reduced back to soluble UF4 by hydrogen gas in a reduction column, and finally is directed to the core to serve as fissile fuel.

The LFTR is not a fast reactor, but with some moderation by the graphite is epithermal (intermediate neutron speed). Safety is achieved with a freeze plug which if power is cut allows the fuel to drain into subcritical geometry in a catch basin. There is also a negative temperature coefficient of reactivity due to expansion of the fuel.

The China Academy of Sciences in January 2011 launched an R&D program on LFTR, known there as the thorium-breeding molten-salt reactor (Th-MSR or TMSR), and claimed to have the world’s largest national effort on it, hoping to obtain full intellectual property rights on the technology.

Safe nuclear does exist, and China is leading the way with thorium

20 March 2011

A few weeks before the tsunami struck Fukushima’s uranium reactors and shattered public faith in nuclear power, China revealed that it was launching a rival technology to build a safer, cleaner, and ultimately cheaper network of reactors based on thorium.

Thorium could be a much safer option for China which has been unsettled by the nuclear crisis in Japan where fears over radiation levels are rising

Thorium could be a much safer option for China which has been unsettled by the nuclear crisis in Japan where fears over radiation levels are rising Photo: AP

This passed unnoticed –except by a small of band of thorium enthusiasts – but it may mark the passage of strategic leadership in energy policy from an inert and status-quo West to a rising technological power willing to break the mould.

If China’s dash for thorium power succeeds, it will vastly alter the global energy landscape and may avert a calamitous conflict over resources as Asia’s industrial revolutions clash head-on with the West’s entrenched consumption.

China’s Academy of Sciences said it had chosen a “thorium-based molten salt reactor system”. The liquid fuel idea was pioneered by US physicists at Oak Ridge National Lab in the 1960s, but the US has long since dropped the ball. Further evidence of Barack `Obama’s “Sputnik moment”, you could say.

Chinese scientists claim that hazardous waste will be a thousand times less than with uranium. The system is inherently less prone to disaster.“The reactor has an amazing safety feature,” said Kirk Sorensen, a former NASA engineer at Teledyne Brown and a thorium expert.

“If it begins to overheat, a little plug melts and the salts drain into a pan. There is no need for computers, or the sort of electrical pumps that were crippled by the tsunami. The reactor saves itself,” he said. “They operate at atmospheric pressure so you don’t have the sort of hydrogen explosions we’ve seen in Japan. One of these reactors would have come through the tsunami just fine. There would have been no radiation release.”

Thorium is a silvery metal named after the Norse god of thunder. The metal has its own “issues” but no thorium reactor could easily spin out of control in the manner of Three Mile Island, Chernobyl, or now Fukushima.

Professor Robert Cywinksi from Huddersfield University said thorium must be bombarded with neutrons to drive the fission process. “There is no chain reaction. Fission dies the moment you switch off the photon beam. There are not enough neutrons for it continue of its own accord,” he said.

Dr Cywinski, who anchors a UK-wide thorium team, said the residual heat left behind in a crisis would be “orders of magnitude less” than in a uranium reactor.

The earth’s crust holds 80 years of uranium at expected usage rates, he said. Thorium is as common as lead. America has buried tons as a by-product of rare earth metals mining. Norway has so much that Oslo is planning a post-oil era where thorium might drive the country’s next great phase of wealth. Even Britain has seams in Wales and in the granite cliffs of Cornwall. Almost all the mineral is usable as fuel, compared to 0.7pc of uranium. There is enough to power civilization for thousands of years.

I write before knowing the outcome of the Fukushima drama, but as yet none of 15,000 deaths are linked to nuclear failure. Indeed, there has never been a verified death from nuclear power in the West in half a century. Perspective is in order.

We cannot avoid the fact that two to three billion extra people now expect – and will obtain – a western lifestyle. China alone plans to produce 100m cars and buses every year by 2020.

The International Atomic Energy Agency said the world currently has 442 nuclear reactors. They generate 372 gigawatts of power, providing 14pc of global electricity. Nuclear output must double over twenty years just to keep pace with the rise of the China and India.

If a string of countries cancel or cut back future reactors, let alone follow Germany’s Angela Merkel in shutting some down, they shift the strain onto gas, oil, and coal. Since the West is also cutting solar subsidies, they can hardly expect the solar industry to plug the gap.

BP’s disaster at Macondo should teach us not to expect too much from oil reserves deep below the oceans, beneath layers of blinding salt. Meanwhile, we rely uneasily on Wahabi repression to crush dissent in the Gulf and keep Arabian crude flowing our way. So where can we turn, unless we revert to coal and give up on the ice caps altogether? That would be courting fate.

US physicists in the late 1940s explored thorium fuel for power. It has a higher neutron yield than uranium, a better fission rating, longer fuel cycles, and does not require the extra cost of isotope separation. The plans were shelved because thorium does not produce plutonium for bombs. As a happy bonus, it can burn up plutonium and toxic waste from old reactors, reducing radio-toxicity and acting as an eco-cleaner.

Dr Cywinski is developing an accelerator driven sub-critical reactor for thorium, a cutting-edge project worldwide. It needs to £300m of public money for the next phase, and £1.5bn of commercial investment to produce the first working plant. Thereafter, economies of scale kick in fast. The idea is to make pint-size 600MW reactors.

Yet any hope of state support seems to have died with the Coalition budget cuts, and with it hopes that Britain could take a lead in the energy revolution. It is understandable, of course. Funds are scarce. The UK has already put its efforts into the next generation of uranium reactors. Yet critics say vested interests with sunk costs in uranium technology succeeded in chilling enthusiasm.

The same happened a decade ago to a parallel project by Nobel laureate Carlo Rubbia at CERN (European Organization for Nuclear Research). France’s nuclear industry killed proposals for funding from Brussels, though a French group is now working on thorium in Grenoble.

Norway’s Aker Solution has bought Professor Rubbia’s patent. It had hoped to build the first sub-critical reactor in the UK, but seems to be giving up on Britain and locking up a deal to build it in China instead, where minds and wallets are more open.

So the Chinese will soon lead on this thorium technology as well as molten-salts. Good luck to them. They are doing Mankind a favour. We may get through the century without tearing each other apart over scarce energy and wrecking the planet.

Government to take new look at fuel-mix

RTHK – 20th March 2011

The Under-Secretary for the Environment, Kitty Poon, says the government will take a fresh look at plans for Hong Kong’s future fuel-mix in the wake of the Fukushima nuclear crisis. Speaking at RTHK’s City Forum, Dr Poon said the territory’s energy supply must be safe, stable, economical, and environmentally-friendly. Last year, the government said it wanted nuclear power to account for 50 percent of Hong Kong’s fuel-mix by 2020 – compared to 23 percent now.

Nuclear crisis has implications for coal

Financial Times – 17th March 2011

The consequences of Japan’s multi-faceted disaster – the earthquake, tsunami and now its nuclear crisis – for the $100bn a year seaborne thermal coal market are slowly becoming clear. Even if over the short-term the impact is mixed, beyond a few months it is decidedly bullish.

The combination will be positive for big coal miners such as XstrataBumi of Indonesia, Anglo American and US-based Peabody , and for the biggest traders of the commodity, including Glencore – which handles around 30 per cent of the seaborne coal market – Noble Group of Hong Kong and US-based Cargill.

Over the short-term, prompt demand for seaborne thermal coal has fallen in Japan, as economic activity slows and, therefore, power consumption. Moreover, several thermal power plants have been damaged, so utilities have asked miners to defer cargoes.

With little appetite for the coal elsewhere in the Asian region – the arbitrage opportunity with China is firmly closed as domestic prices there are low – thermal coal prices in the Australian port of Newcastle, a benchmark for the Pacific basin, have remained stable at around $128 a tonne, below the two-year peak of $135 in January.

But demand will rebound as big factories reopen in Japan and the reconstruction starts. With nuclear power severely constrained, coal-fired power plants will be run harder, particularly in the peak months of June-September of electricity consumption. The extra demand could add 500,000 tonnes a month to Japan’s consumption of around 10m tonnes per month in the second half of the year. Some utilities will also need to rebuild stocks, which were washed away by the tsunami.

The negotiations for the 2011-12 annual contracts in Asia, which faced a deadline of April 1, are now postponed. But still, the strength of the market before the quake and the medium-term boost for Japan’s coal needs are likely to see a settlement in excess of the $125-a-tonne record of 2008-09. Indeed, traders tell me that some miners have tabled an initial proposal for $140-$145 a tonne, pointing to a final settlement above $130 a tonne.

The impact of the crisis – both short- and long-term – is been felt more acutely in Europe, where prices are rising rapidly. Japan will not only run its thermal coal-fired power stations harder, but will also buy more liquefied natural gas to produce electricity. LNG cargoes, particularly from Qatar, will move to Japan, rather than heading to Europe, thereby pushing up gas prices in the UK and continental Europe.

The stronger and more sustained increase in gas prices is already making coal more attractive as an option for generating electricity in Europe. This is demonstrated by an increase in what is known as the “dark spread”, the profit margin made from burning coal and selling the resultant electricity, as compared with the equivalent “clean spread” for LNG; as well as by rising demand for coal. Prices are higher in the Atlantic basin and in Rotterdam – the benchmark in Europe – as well as in Richards Bay – the South African yardstick.

The cost of thermal coal in Rotterdam has already risen nearly 11 per cent since the earthquake to $135 a tonne, a 2½-year high. Besides, Germany’s decision to idle a large chunk of the country’s nuclear power stations for at least three months amid the Japanese nuclear crisis will also increase demand for coal as a replacement.

During the last five years, coal miners saw Europe and Japan as mature markets, with all the growth potential in developing countries such as China and India. If Tokyo and Berlin retreat from nuclear power, Europe and Japan could again be growth markets.

CLP Power hails emissions cut

South China Morning Post — 10 Mar 2011

Hong Kong’s largest power supplier yesterday gave itself a pat on the back for its work to reduce emissions.

CLP Power (SEHK: 0002) reported that its Hong Kong power plants burned more gas and less coal for electricity last year. And it is confident that its gas supply will be stable for the next two years, before a transcontinental pipeline through the mainland comes online.

Under a 2008 agreement, Hong Kong will receive natural gas from Turkmenistan in Central Asia through the West-East Pipeline network, beginning next year or in 2013.

About 30 per cent of the company’s fuel mix was natural gas last year, compared to 25 per cent in 2009, while the proportion of coal used fell from 45 per cent to about 40 per cent. The rest is nuclear energy imported from Guangdong.

The change in the fuel mix, along with new emission control devices at its coal-fired power plant last year, brought down the emissions of major air pollutants by 58 per cent.

Carbon dioxide emissions fell by about 6 per cent, from 19 million tonnes in 2009 to 17.9 million tonnes last year.

The power firm warned of depleting gas reserves in Hainan which had caused disruption to its natural gas supply.

Lo Pak-cheong, CLP Power’s commercial director, said he was not worried about the continuing gas supply from the reserve but he anticipated challenges in bringing in the new gas supply.

“We have regular assessment on the supply, and close liaison with our mainland partners. We are confident that there will be sufficient gas before the coming of the new supply that will enhance supply reliability,” said Lo.

CLP would also source gas from a liquefied natural gas terminal to be built in Shenzhen and continue to use the existing Hainan reserve.

The company was also preparing to import more nuclear energy from the mainland.

China WindPower plans sales to fund investment in wind farms

South China Morning Post – 09th March 2011

China WindPower Group has embarked on a “sell some, build more” wind farm development strategy, as it seeks to realise gains from its past investments and generate cash flows to fund new projects.

The firm plans to sell 100 to 150 megawatt (MW) of its wind power plants each year to book 25 to 50 per cent gains and generate cash flow to fund more new projects, chairman Liu Shunxing said.

“We are selling our stakes in some plants, not only to our partners but also third parties,” he said. “This way we can bolster our resources for new projects, which we hope to be able to wholly own in the future.”

The firm owns stakes of various sizes in its current projects, which averages around 60 per cent, said chief financial officer Hu Mingyang.

It yesterday posted a net profit of HK$427.2 million for last year, up 135 per cent from 2009. This beats the HK$322 million average forecast of seven analysts polled by Thomson Reuters by almost a third, partly helped by unexpected one-off gains totalling HK$21 million from the sale of its 49 per cent stakes in two plants of 50 MW each last year.

The main source of profit growth last year was from its investment in wind farms, whose contribution to net profit grew to 28 per cent from 18 per cent in 2009. It also earns money from consultancy and project design, engineering and construction, operation and maintenance, as well as wind tower tube production.

Liu said the company aimed to quadruple capacity at invested projects to 4,663 MW by 2015 from 1,163 MW last year, by adding at least 700 MW in new installations each year. Of last year’s 1,163 MW, 657 MW is owned by the company based on its shareholding. Most projects are in north and northeastern provinces.

It takes about 1,000 MW to provide 831,000 mainland households’ annual electricity consumption.

With equipment costs down from 5 million yuan (HK$5.9 million) per MW in 2009 to 3.6 million yuan, Liu said the firm would diversify into southern provinces.

The company has secured over 4,000 MW of wind resources in the south and 15,000 MW nationwide. China WindPower has also obtained 648 MW of solar power resources, but Liu said it was waiting for better incentives before developing them.

It would only invest in wind projects that can provide a 10 per cent return on investment and at least 8 per cent for solar projects, Liu said.

HK on course to reach emission-reduction target

South China Morning Post — 4 Mar 2011

Hong Kong looks likely to reach or even surpass air pollution-cutting targets under a cross-border pact – a payoff for retrofitting the city’s largest coal-fired power plant with emission control devices, said Edward Yau Tang-wah, secretary for the environment.

But it remains unknown whether neighbouring Guangdong has achieved the targets agreed with Hong Kong in 2002. The two sides aimed to cut emissions of major pollutants by 20 per cent to 55 per cent below 1997 levels by 2010.

“Although the final emission figures are still being complied, I am very confident that on our side, Hong Kong will meet or even surpass the targets. I think this is what the public want to see,” Yau said at a ceremony to mark the completion of the emission control project by CLP Power (SEHK: 0002).

CLP Power emissions in 2010 generally fell by 60 per cent compared with the base year 1997, outperforming the reductions required by the government, the company said.

While Hong Kong and Guangdong were still discussing how to further reduce emissions in the next decade, Yau said the next steps for  local power plants were stricter emission caps and a greener fuel mix.

According to CLP Power, emissions at its two operating power stations for three major pollutants last year were 28 per cent to 58 per cent lower than 2009. But it did not provide a breakdown for individual stations.

It said some reductions were made possible by the introduction of low-sulphur coal in 2005. But most of the improvements came from retrofitting four coal-fired generation units, 667 megawatts each, at the Castle Peak Power Station with  devices that can reduce levels of sulphur dioxide, nitrogen oxides and  respirable suspended particles.

The HK$9 billion retrofit equipped the plants with scrubbers that can remove sulphur dioxides by up to 90 per cent and selective catalytic reduction devices that can cut nitrogen oxides by up to 80 per cent.

Three of the four units are now in full operation and the last unit is  expected to start running by this year’s second quarter. The retrofit programme does not cover older generation units with a total of 1,400 megawatts; these units, which date to at least 1982, are near the end of their lifespan.

Richard Lancaster, managing director of CLP Power, said the retrofit had made the power station one of the cleanest coal-fired power plants in the world.

“It is an important milestone in a journey,” Lancaster said, “and the government has set us further milestones: new emission caps in 2015 and fuel mix in 2020, which are challenging targets for us.”

The 2015 cap will require the power supplier to cut emissions by up to 64 per cent below 2010 levels.

The government has also proposed changing its reliance on different sources of electricity to a mix of 50 per cent nuclear, 40 per cent gas and 10 per cent coal by 2020. Coal, nuclear and gas each account for a third of CLP’s electricity.

Asked if the retrofit would be made redundant if coal-fired power generation is to shrink, Lancaster said the retrofit would still be needed in the next 10 years.