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These are questions that the Communications Office have received via email from the website audience; hence the rather conversational tone. We attempt to answer each question with the available facts. The top FAQs are the ones that receive most views on our website. If you have a question, write to us!
While it might seem confusing that energy can be generated by both fusion and fission, as they appear to be quite opposite processes, the explanation lies in the size of the nuclei.
The colour comes from the fuel, which is basically hydrogen. Hydrogen gives out two different colours, a strong red and aqua-blue, which combine to give the pink colour that shows up in most pictures.
An alpha particle is produced by the alpha decay of a radioactive nucleus. Because the nucleus is unstable a piece of it is ejected, allowing the nucleus to reach a more stable state.
The fusion reaction releases neutrons, which would be quite dangerous to humans, however the production of neutrons ceases within milliseconds when the plant is turned off.
For fusion to occur we need to create and maintain plasma at extremely high temperatures. Additionally we need to contain the plasma by energising large magnetic coils.
As the ions in the plasma are charged they respond to magnetic fields. By setting up magnetic field lines toroidally around the interior of the tokamak, the ions and electrons in the plasma are forced to travel tightly around these field lines.
JET, so far the only operational fusion experiment capable of producing fusion energy, is routinely operated with Deuterium only, for a number of reasons.
The answer is one of the key advantages of fusion as a potential energy source over nuclear fission power stations – its inherent safety.
Breakeven is achieved when the energy from fusion reactions is larger than the energy required to sustain the plasma.
In order for fusion to occur in the very hot gas – or plasma –created inside JET, the plasma must be heated to temperatures in excess of 150 million degrees Celsius.
The blanket is a layer surrounding the vessel in a fusion powerplant. It will absorb the energy from the fusion neutrons produced in the plasma, boiling water via a heat exchanger, which will be used to drive a steam turbine and produce electricity.
Strangely enough, the sun is a very inefficient fusion reactor, producing only 1 watt per cubic metre – luckily it is very big so the total is a lot of power. Here on earth we are aiming for efficiencies a million times better than that!
Most of the experiments that are carried out in fusion research use only deuterium, rather than a combination of deuterium and tritium (D-T).
The First Law of Thermodynamics explains how the amount of energy gained from something cannot exceed the amount put in. So it seems to violate the laws of thermodynamics – but…
In fission, energy is gained by splitting apart heavy atoms into smaller atoms whereas fusion is combining light atoms, which form a heavier one. Both reactions release energy.
Using nuclear fission and fusion for generating electricity requires very different technologies and engineering.
Fusion releases energy when the nuclei of two forms of hydrogen (in our case, we use deuterium and tritium) are collided together at such high velocities that they stick together or fuse.