'A sun of our own - and it’s made in Britain', screamed the Daily Sketch in January 1958. The front page went on to claim that British scientists had 'Sputniked' their apparently invincible Soviet rivals by creating nuclear fusion in the laboratory. Surely it would be only a few years before Britain's shiny new Magnox nuclear power stations - a genuine world first, incidentally - would be replaced by reactors running on water and generating electricity almost too cheap to bother metering.
Of course it didn’t happen. The Magnox stations, and their successors, the advanced gas cooled reactors, were eventually replaced - scandalously, we belatedly realise - by thermal power plants fueled with coal and gas. Since that let-down we have become used to the idea that fusion power will always be at least a generation away.
Until this week’s announcement that a US team had achieved the basic breakthrough of running a fusion reaction generating more energy than that put in. Practical application of the breakthrough may still be a generation away - but from now that timescale will be shrinking rather than a permanent fixture.
Fusion is tantalising because, unlike some other speculative technologies - strong artificial intelligence and quantum computing spring to mind - we can be certain that it works. After all, our planet is habitable only because it orbits a moderately sized - by cosmic standards - fusion reactor.
Even more tantalisingly, the science is understandable at GCSE level: strip hydrogen atoms (which, you’ll remember, consist of a single proton and electron) of their electron and whack the protons with sufficient energy to overcome the positive-to-postive electrostatic repulsion so they get close enough for the strong nuclear force - which functions only at tiny distances - to take over. The protons thus fuse into a new nucleus - helium - with less than double a single proton’s mass. The excess mass turns in to energy. For light nuclei the process is exothermic - it produces more energy than was put in.
But, if the science is straightforward, the engineering required to recreate the sun on a manageable scale are formidable. Hence the 70 years of international effort and many billions of pounds expenditure. The UK made a significant contribution by hosting the Joint European Torus, a ring doughnut-shaped accelerator in which streams of plasma confined by giant electromagnets collide at extreme speed.
The US breakthrough by the National Ignition Facility at the Lawrence Livermore National Laboratory in California was achieved with a different approach, in which a massive array of laser beams heats and compresses a pellet of hydrogen (actually a mixture of deuterium and tritium, with, respectively, one and two neutrons bound to the proton). The experiment produced 3.5 megajoules of energy from a 2.05 megajoule input (plus the substantial amount of electricity firing up the lasers).
Of course there is a massive gap between a one-off experimental success and a viable technology. But we once used to be able to crack these things. Only 14 years elapsed between the creation of the world’s first atomic pile, in a University of Chicago squash court, and the opening of the Calder Hall nuclear power station; only three months between the first test flight of the Lunar Excursion Module (with human astronauts on board) and the actual moon landing.
Different times. And none of us would wish for a return to the wartime imperative which put so much technological development on overdrive in the mid twentieth century. But are we not experiencing a climate crisis, in which the burning of fossil fuels puts at risk more lives than were lost in the second world and cold wars put together?
It is high time for people concerned with the issue to get behind the only technologies that present a real prospect of meeting the UK government’s legally binding net zero commitment. (Which we may as well stick to, even though it will make little direct difference globally.)
Tragically, it seems easier to mobilise a 'just stop' movement than a 'just start' one. Consider the ongoing struggles over building new nuclear fission capacity, 27 years - twenty seven years! - after our newest nuke came on line. And fission power is a globally proven safe technology. (It is also about the only industry that takes the waste question seriously. We’re already lumbered with looking after medical and military nuclear waste; a few new power stations will not add much. And radioactivity, by definition, decays over time, which is what 'half-life' means. The cadmium in your mobile phone will be toxic forever.)
Fusion, with its unknowns and scary engineering extremes, can expect to attract scepticism, nimbyism and downright luddism. Lawyers should be wary of contributing to any of this.
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