Nuclear Fusion
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magine a source of electricity where the fuel comes from water, fuel supplies will last for many thousands of years, the whole process is inherently safe and, most importantly of all, no carbon is produced. That is the promise of nuclear fusion – and it is turning from science fiction to science fact.
Harnessing the power of the Sun The fusion of hydrogen to make helium is what makes the Sun shine – and it has long been mankind’s dream to harness this powder directly here on Earth. So why is fusion electricity not on the grid? The simple answer is that it is very hard to do. The optimum fusion reaction fuses two isotopes of hydrogen (deuterium and tritium) to produce helium, a neutron and excess energy – but it requires the hot gas or ‘plasma’ of fuels to be heated to temperatures of around 150,000,000ºC. The most advanced approach is a device called a tokamak (first developed in Russia in the 1960s), in which a powerful magnetic field is used to hold the plasma inside a ring-shaped vessel. In future power plants, the fusion neutrons (which contain most of the excess energy) will be slowed down in so-called ‘blanket modules’ positioned around the vessel walls. These get very hot and can produce steam to drive turbines that make electricity.
Making fusion work The UK leads the world in developing this transformative technology, with the UK Atomic Energy Authority’s (UKAEA) work at Culham Science Centre in Oxfordshire at the forefront. For example, UKAEA operates the world’s largest and most advanced tokamak – JET – on behalf of European fusion researchers. JET is the only tokamak in the
The STEP programme is a staged programme to design and build the world’s first compact fusion reactor by 2040 42 energyfocus | www.the-eic.com
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