Monday, 1 November 2010

Hot doughnuts and cold fusion: a never-ending story?

When there is much at stake we have a tendency towards self-delusion, ignoring unpleasant facts and concentrating instead on elements that will hasten our goal. If there is any such thing as a holy grail in contemporary science it surely has to be power generation via nuclear fusion, seemingly "just decades away" for rather more than that length of time. So are fusion researchers allowing dreams to obfuscate the facts?

The first fusion research was conducted in the 1950s by the Soviet Union, using doughnut-shaped magnetic field generators called tokamaks. Since then, various methods have been attempted with varying degrees of success, although none have achieved the ability to offer a greater output of energy than the amount input. A prominent contemporary non-tokamak project is the Lawrence Livermore Laboratory's National Ignition Facility in California. The project's integrated ignition experiments started this month after 13 years' development, using 192 lasers to create an energy pulse thirty times greater than ever achieved previously. At a cost of £1.2 billion, the NIF is seen by many as the best hope yet, but is now at least 25% over budget as well as behind schedule.

Meanwhile, tokamak research is continuing at various facilities, the best known being Iter (Latin for 'the way' but initially ITER - the International Thermonuclear Experimental Reactor - at least until 'thermonuclear' was deemed an unpopular word). Now being constructed in France, Iter is a collaborative effort between the EU, the US, Japan, Russia, China, South Korea and India. It is due for completion around 2019, but at a cost of £13 billion, it is also way over original estimates. The list of collaborators alone shows the importance of this immense project: after all, the dream of limitless energy for our descendents is worth the comparatively small effort in our time (although interestingly the Canadian Government was unable to remain in the project due to lack of funds). Britain itself contributes only about £20 million to the project each year, but in addition hosts the world's most powerful tokamak, namely the Joint European Torus (JET) in Oxfordshire.

Whilst fusion researchers publicise the advantages over current fission power stations, successful nuclear fusion at Iter would still produce thousands of tonnes of radioactive waste, albeit dangerous for only about a century as opposed to the millennia for the half life of fissile waste materials. In addition, critics claim the immense costs would be better spread across a range of fusion projects utilising different techniques, whilst environmental groups point out the money could build immense numbers of renewable 'green' power generators, from wind farms to solar collectors.

Indeed, it does seem that the member nations are putting all their eggs in one basket, considering the failures and hyperbole of the past few decades. In 1989, claims of cold fusion turned out to be premature when the results could not be replicated, whilst a 2002 claim for bubble fusion (sonofusion) also appeared to be precipitate. However, this hasn't led to scientists and engineers abandoning these techniques in favour of tokamaks or laser fusion. So is the immensity of the potential reward enough to keep researchers flogging a dead hypothesis? Then again, if the NIF and Iter fail to produce satisfactory results after a few years' operations, perhaps another generation of scientists and engineers will reconsider these somewhat discredited techniques.

One interesting development in recent years is the growing community of amateur physicists who are building homemade fusion reactors for as little as £30,000. As bizarre as it sounds, most of the materials are fairly easy to obtain, but unlike amateur astronomers for example, it is easy to wonder how these pint-size projects can compete with the billion-pound schemes mentioned above. The amateurs claim that their attempts may serve to initiate professional interest (and funding) in their non-tokamak methods. In view of the potential dangers of electrocution and x-ray radiation, their dedication is clearly admirable, if a little crazy. Then again, our species has rarely achieved a paradigm shift by playing it safe.

What is obvious to many is that we cannot afford to stop investing in large-scale fusion research: success would mean a relatively safe supply of non-fossil fuel energy for areas of the world where wind, wave and solar power cannot offer an on-demand supply. Nuclear fusion would not be at the mercy of the weather, nor occupy the immense amounts of space required for wind and solar farms, even if the former are offshore.

My own opinion is that fusion power will be an unfortunate necessity, at least until we can reduce energy consumption and the human population to sustainable levels - the latter being possibly rather less likely than building a break-even fusion reactor within a human lifetime. Research over the next decade will continue to consume enormous amounts of money, but only posterity will show if this is a great enough effort to stem the deleterious consequences that fossil fuels are having on the politics and economy of our species, in addition to the irreversible ecological effects rapidly coming over the horizon.

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