What is nuclear fusion?

Nuclear fission power is part of the answer but is not the whole solution to achieving a low carbon economy. The development of nuclear fusion technology could also be very important.

Is nuclear the future?

A nuclear fusion reaction can release tremendous amounts of energy. The sun, stars and thermonuclear warheads (H Bombs) are all powered by nuclear fusion. 

ITER site

Conventional nuclear power stations convert heat energy produced from a nuclear fission chain reaction into electricity. Heat energy is released when very heavy uranium atoms break apart. However it is also possible to generate heat from a nuclear fusion reaction.

Nuclear fusion works in the opposite way to fission by joining very light atoms together. For example the experimental Joint European Torus (JET) fusion reactor in Oxfordshire fuses together deuterium and tritium atoms to produce helium. However it is not easy to make fusion work in a controlled way. The fusion reaction takes place inside a doughnut-shaped torus within an extreme electromagnetic confinement field to hold the reacting plasma together.

ITER reactor

JET consumes more electrical energy than is produced by the fusion reaction and the reaction is unstable lasting for only a few fractions of a second. A larger scale version of the JET fusion reactor, the €5 billion International Thermonuclear Experimental Reactor (ITER) is presently being designed and constructed near Cadarache in France for start-up in 2018.

Despite these problems the perfection of working nuclear fusion reactor technology could have a profound beneficial effect on humanity for three major reasons. Firstly, the deuterium and tritium fuel can be extracted from seawater, offering a highly secure and effectively infinite fuel supply to any country. Secondly a fusion reactor produces no hazardous spent fuel radioactive waste. And thirdly, the fusion reaction is intrinsically fail-safe so cannot meltdown like a fission reactor.


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