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Nuclear power for the 21st Century pt1 – Cosm Dec 11, 2009

All the power of the Sun – Part 1

Nuclear fusion – How HiPER will use lasers to create a 'star on Earth' to power the planet

In the 1940s the words ‘nuclear power’ summoned images of a futuristic energy source, available in the here and now. It was going to revolutionise, well, everything. It would provide all our electricity needs, power our ships and submarines and ‘in the future’ we would all be driving around in nuclear-powered cars.

Sixty years later and nuclear power is a dirty word that summons images of apocalyptic weaponry, meltdown, death and is blamed for the creation of countless superheroes and twenty-storey high Japanese monsters. The trouble with current nuclear technology is that it uses a process called nuclear fission which basically involves taking highly radioactive unstable atoms and tearing them apart to release some of the energy pent up within.

While, when they are working, fission reactors are pretty efficient at generating power, the whole process – from mining to enrichment and reaction to disposal – is environmentally dirty and dangerous from start to finish.
Unfortunately, other than renewable energy sources like wind and solar which are likely to never be more than supplementary at best, the only alternative to nuclear power is good old fossil fuels and, crushing pressure that allows the process to work deep in the heart of the Sun.

Two solutions to this problem are emerging as strong competitors. One generates 100million degree plasma and crushes it in a magnetic field. The other uses a staggeringly powerful laser to zap a pellet of fuel and create a miniature Sun.

The High Power Laser Energy Research Facility (HiPER) is headed up by Britain’s Science and Technology Facilities Council and is currently one year into a threeyear feasibility study. If approved for construction, it will use a colossal, football stadium-sized laser to blast a tiny pellet of ‘heavy’ hydrogen. The blast will generate pressures that crush the 2mm pellet to a hundredth of its size in a billionth of a second. A second blast will heat it to more than 100million degrees Celsius – about ten times hotter than the centre of the Sun – crushing together the hydrogen atoms that make it up and forcing them to fuse into helium – just like it does it in the Sun.

The challenges facing its engineers are staggering. To ignite the fuel – which is a 2mm pellet fired into the centre of a ten-metre wide sphere and which must be tracked and targeted precisely – will require a laser capable of deliver 10,000 times more power than is carried by the entire national grid (for a fraction of a fraction of second at least). To generate enough energy to be useful as power station, a pellet will need to be ignited at least five times every second. And, at an estimated cost of £1billion, this kind of technology doesn’t come cheap but, then again, nothing worth having ever did.

This week's graphic – How laser fusion works (and what's the difference between fusion and fission)

Click image below to view the page and download in high-resolution