Nuclear power is the only source of base load electricity capable of meeting global energy demands whilst also mitigating against the risks of climate change. Unfortunately public perception of nuclear power is often coloured by issues of safety, radiotoxic waste, and links to proliferation.
Might the nuclear option be more acceptable if we could define an alternative nuclear technology? One that has inherently higher safety margins than conventional reactors; that is low waste; that does not include plutonium as part of its fuel cycle; that is intrinsically proliferation resistant; that can effectively burn legacy radiotoxic waste; and is both sustainable and cost effective.
Surprisingly such a technology does exist, and it is based not upon the uranium/plutonium fuel cycle but upon the element thorium. Indeed, thorium has been regarded as a potential nuclear fuel almost since the start of the nuclear age. Several conventional reactors in the US, Germany and Britain have already used thorium fuel and proved its viability. Additionally, unconventional but viable approaches, such as the thorium molten salt reactor (MSR) at Oak Ridge, were also demonstrated in the 1960s.
Thorium is four times more plentiful than uranium and, significantly, only 5,000 tons of thorium could produce the entire energy needs of the planet for a whole year. There is also enough thorium available in known deposits to provide energy for ten thousand years. Although thorium itself doesn’t undergo fission, it can be converted to fissile fuel by seeding with uranium or plutonium, or by providing neutrons from an external source by spallation.
As thorium is burnt, unlike conventional uranium fuel, it produces almost no plutonium, the highly toxic and potent ingredient of nuclear weapons. In fact, it is often claimed that it is thorium’s inability to produce plutonium for the military which caused the thorium fuel cycle to be abandoned at the height of the cold war.
Not only does thorium produce orders of magnitude less radiotoxic waste than uranium legacy waste from existing power stations could be effectively transmuted and burnt as fuel in the so called Accelerator Driven Subcritical Reactor (ADSR) systems , thereby turning a liability into an asset and removing the need for long term geological storage.
India, with its substantial deposits of thorium, is now actively pursuing thorium-based nuclear technology, ironically by mixing thorium with specially bred plutonium. Research is underway in Japan to resurrect the thorium molten salt concept, whilst Norway, particularly rich in thorium, is also considering the potential of exploiting its deposits as an energy resource beyond North Sea gas and oil.
China, where thorium is produced in great quantities as a toxic bi-product of rare earth metal mining, is also investing heavily in thorium nuclear research and particularly in MSR and ADSR technology.
And in the UK?
Unfortunately there are no coherent government, industrial or academic policies on the development and deployment of thorium nuclear technology. Yet the UK is rich in expertise in materials, reactor design, molten salts, spallation and accelerator technology.
One has only to look to the thorium research programmes at the Universities of Oxford, Cambridge and Huddersfield, and of course at the capabilities of the National Nuclear Laboratories to see what could be achieved.
Even modest investment in an advanced thorium R&D programme could provide the UK with a unique opportunity to create, build and sustain a multi-billion pound nuclear industry based upon safe, inexhaustible, low waste and proliferation-resistant nuclear power generation. It could also allow the UK to compete in existing nuclear markets whilst opening up new international markets that at present are closed to current nuclear technologies and provide energy security at home.
The Weinberg Foundation, the All Party Parliamentary Group on Thorium (chaired by Baroness Bryony Worthington), and the academic Thorium Energy Association are all working towards building a consensus on an alternative thorium fuelled nuclear future.
But without strong support from Government and an industry which is currently strongly wedded to existing uranium-based technologies it is likely that the UK will miss yet another golden, or in this case silver, opportunity.
Professor Bob Cywinski is Dean of Applied Sciences at the University of Huddersfield