The nuclear power stations of the future
The nuclear power cognoscenti welcomed the election of Jimmy Carter as President of the USA at the end of 1976. He was the only world leader with hands-on experience of nuclear matters, having worked with Admiral Rickover, the creator of Nautilus – the first nuclear submarine. The nuclear industry was expecting encouragement and nuclear-friendly legislation to flow from the White House. They were disappointed – almost the first act of the new President was to cancel Clinch River, the US fast reactor, and to ban reprocessing of spent thermal reactor fuel of American origin, at home or abroad.
Fast reactors to preserve the Earth's natural resources
The nuclear fuel cycle favoured before Carter’s intervention would have involved reprocessing spent thermal-reactor fuel to separate out the plutonium. This would power a series of fast reactors that could generate more plutonium in their fertile blankets than was consumed by running the reactors.
Such a fuel cycle would increase the amount of heat or electricity generated from a given quantity of uranium by almost two orders of magnitude (compared to the ‘once through’ nuclear cycle). It would make the world’s reserves of uranium ore a virtually inexhaustible source of energy, to which could be added the Earth’s reserves of thorium – an element that can also be applied to sustain a breeding cycle.
If in the future mankind exhausted the reserves of fossil fuels, or found their continued use too contaminating, then nuclear power that incorporates the fast reactor could in principle provide most of our energy needs, at least for several millennia.
Carter feared that the global adoption of a plutonium fuel cycle for electricity generation would inevitably lead to it being diverted for weapons production. He could point to India’s nuclear bomb test of 1974, which employed plutonium that was extracted from the spent fuel of a research reactor supplied by Canada for peaceful purposes and which used for its moderator heavy water supplied by the USA under the aegis of the ‘Atoms for Peace’ policy.
If President Carter took a rather cavalier view of the potential long-term benefits of the fast reactor, he did not exhibit similar harsh judgements on the well-funded US fusion project. Superficially, fusion seems to have a lot in its favour – it is potentially an ‘infinite’ energy source. To illustrate, the lithium in a laptop computer battery could provide a lifetime’s worth of electricity. There are no fission products, so a fusion reactor creates only a minor nuclear waste problem, and if you flew a plane into a fusion reactor, very little radioactivity would escape.
Building a fusion reactor
However, all these advantages cannot compensate for one huge disadvantage. To achieve fusion, the reactor would need to reach a temperature of 100 million degrees Celsius, equivalent to 10 times hotter than the sun. It is entirely possible that a successful fusion reactor will never be achieved. This was the view of one of America’s fusion pioneers, William Parkins, who earlier this year in the Science journal pointed out that the USA has spent $20 billion on fusion over 50 years with no success and it was time to give up.
Nevertheless, last May, the EU, USA, China, India, Japan, Russia and Korea signed a treaty to build the International Thermonuclear Experimental Reactor, the world’s largest fusion reactor, at Cadarache in Southern France. I wish them well but I recall Hermann Bondi’s advice – if you have to choose between fission and fusion, choose fission. At least we know a fast reactor works. But do we have to choose – what is wrong with belt and braces?
'Energy Impasse', The Evening Independent, 15 September 1980, report on the Clinch River reactor