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Renewable Energy

Nuclear Fusion

ITER reactor due to be built in France soon. Click to enlarge.

Nuclear fusion is the process that drives the sun! It is the opposite of Nuclear Fission, which drives current nuclear power stations. In fission, atoms are split apart to release energy. In fusion, two small atoms are squeezed together so much that they fuse into a single new atom, releasing energy as they do so.

Advantages of Fusion

  • Unlike fission, nuclear fusion should be safe. Fusion can only take place under extreme pressure, when a gas is heated and squeezed as much as it is in the sun and other stars. This is done inside a very powerful magnetic field that contains and squeezes the gas. If for some reason the containment field fails, the pressure drops and the fusion reaction shuts down. It simply cannot explode.
  • Fuel for fusion will never run out - it can be filtered from sea water
  • Fusion produces only very small amounts of relatively short lived radioactive wastes.


  • Despite 50 years of research, scientists have not yet been able to build a fusion reactor that works continuously so that it can be used as a power generator.
  • It is very expensive to develop, as research requires creating conditions in the laboratory the same as at the core of the sun.

In theory, nuclear fusion offers the promise of cheap, plentiful, non polluting energy. But nobody knows just how long it will take to make it work.

Next: Wind power


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Cost of knowledge

The proposed costs are €10 billion for the construction of ITER, its maintenance and the research connected with it during its lifetime. That is a massive sum, is it worth it?

The European Union has recently decided to spend £7 billion on  building a nuclear fusion reactor in France. It is not expected to produce power until 2040.

Question: Given the urgency to find non-polluting energy sources to avoid climate change...
1) Do you think it is a good idea to spend such a large amount of money on a technology that is great in theory, but is still unproven?
2) Would the research costs be better spent on other renewable energy sources?


 BBC Guide to 
      Nuclear Fusion
 ITER Project