What is Thorium?
Thorium is a naturally-occurring mildly-radioactive element named after Thor, the Norse god of thunder. When used as a fuel in nuclear reactors, particularly molten salt reactors, it can be used to generate huge amounts of safe, zero-emission energy.
Thorium is one of the most energy-dense elements found in nature: it has been estimated that just 5,000 tonnes of thorium contain enough energy to meet the world’s total energy demand for an entire year. 5,000 tonnes may seem like a lot, but in 2011 the world used over 6 billion tonnes of coal alone.
Thorium is around three-to-four times more abundant than uranium, with particular concentrations in Australia, China, India, Norway and the United States. It is often found alongside deposits of rare earths.
Astonishingly, thorium is currently dumped as waste, rather than being valued as a vital source of clean energy for the 21st Century. The Weinberg Foundation’s mission is to revive interest in this forgotten element and place thorium energy technologies at the centre of the global energy debate.
MOLTEN SALT REACTORS
Molten Salt Reactors (MSRs), first designed, built and proven by Alvin Weinberg at the Oak Ridge National Laboratory, have the potential to revolutionise the world energy supply, allowing us to replace our fossil fuel-based energy system with clean, safe and economical nuclear energy.
Whereas the current generation of nuclear reactors use solid fuel rods, MSRs use a liquid fuel. This fundamental difference leads to benefits that other reactors cannot match:
- Efficiency: Solid-fuelled nuclear reactors are to use just 1% of the total energy in the fuel rods before the rods degrade and must be replaced. MSRs are able to use up to 99% of the available energy in the fuel, greatly reducing the amount of high-level waste produced by the reactor and increasing the efficiency of resource-use.
- No more meltdowns: MSRs have built-in features that make meltdowns impossible. In normal operation, the liquid fuel expands as it increases in temperature, thereby slowing the reaction and acting as a natural brake on the reactor’s temperature. All MSR designs include a plug of frozen salt at the bottom of the reactor. Should a major loss of power or other incident occur, the operators can simply drain the reactor fluid into a safe containment tank beneath the ground.
- Inherently safer: Unlike current reactor systems, which have to operate at many atmospheres of pressure, MSRs operate at natural atmospheric pressure. This means that MSRs are inherently safer to operate, as the risk of a pressure leak and resulting explosion is non-existent.
- Mass-producible: MSRs, which are much simpler than current reactors, lend themselves to modular mass production, much like airliners are built today. This would give MSR manufacturers great economies of scale, thereby reducing the cost of the reactor and allowing rapid deployment of MSRs to replace our fossil fuel infrastructure. Small and modular MSRs could be combined on-site to create large-scale power plants.
THORIUM-FUELLED MOLTEN SALT REACTORS
Thorium-fuelled MSRs (Th-MSRs) offer all the advantages of uranium or plutonium-fuelled MSRs with additional benefits that add up to an extraordinary breakthrough in clean energy. Key benefits of Th-MSRs include:
- Ability to ‘burn up’ nuclear waste from other reactors either as the main nuclear fuel in the reactor, or as start-up fuel to trigger the thorium fuel cycle. Th-MSRs would turn global stockpiles of plutonium and enriched uranium from a liability into an asset.
- Greatly-reduced waste: Th-MSRs would produce only 100 grams of plutonium for every tonne of thorium used. 87% of the waste produced would be safe within a decade.
- Proliferation resistance: It is not possible to enrich thorium to make weapons-grade material. The very small amounts of plutonium produced by Th-MSRs, and the great technical difficulty of extracting it, further reduces proliferation risk.
- Production of medical isotopes: Th-MSRs would produce valuable medical isotopes as a by-product, so safeguarding the world’s supply of material for nuclear medicine.
A longer and fully-referenced version of this page is available here (PDF link).
Thorium and MSRs in the media
- Is there a safer future for nuclear? Dr Geoff Parks, Cambridge University, June 2012
- Safer nuclear – let the thorium debate begin, SmartPlanet, May 2012
- New Life for Forgotten Fuel, FT Magazine, September 2011
- The Nuclear Renaissance?, BBC Business Daily, September 2011
- Thor Forges Safer Nuclear Power, The Sunday Times (PDF 1.6 Mb)
- Thorium: the Element that Could Power our Future, Wired.co.uk, September 2011
- Safer nuclear does exist, The Telegraph, August 2011
- Why thorium nuclear power shouldn’t be written off, Bryony Worthington, The Guardian, July 2011
- Uranium is so last century – enter thorium, the green nuke, Wired, December 2009
- See our News page for the latest news about thorium, MSRs and the Weinberg Foundation
- Visit our Resources page for links to other thorium associations, books, blogs, key academic articles, multimedia and more
- See our Media page for a selection of YouTube videos and images