In light of recent breakthroughs regarding nuclear fusion power, here’s Impact’s quick guide to this developing energy source.
What is nuclear fusion?
Nuclear fusion, as suggested by the name, involves the fusing together of nuclei. The sun uses it as an energy source. At the Sun’s core the temperature and pressure are so high that nuclei of atoms get closer and closer together and eventually fuse making one, large nucleus. Fusing small atoms (like hydrogen and helium) together releases a huge amount of energy – approximately 3 to 4 times that produced by current techniques.
How does it differ from current nuclear power?
At the moment, nuclear power stations use a process called nuclear fission. This is the opposite of fusion because it takes large, heavy, unstable atoms of uranium and splits it into smaller atoms, which releases energy. The breakdown also produces a fast moving alpha particle (made of 2 neutrons and two protons). This then collides with another uranium atom which causes it to break down and the cycle continues in a chain reaction until the uranium is almost all used up and is replaced.
Why are we not using fission at the moment?
Scientists have been trying for many years to develop a nuclear fusion reactor that could be used in a power station but have encountered many difficulties.
The problem with fusion is that it requires such a large amount of energy to get it going.
The temperature has to exceed millions of degrees in order to strip the electrons away from the nucleus before fusion can commence. The pressure to force the nuclei together is created using incredibly strong magnetic fields and these require a lot of electrical power to maintain. Because of this, it wasn’t until February this year that a fusion reactor gave out more energy than it takes to run (but only for 150 picoseconds!). While setting up these initial conditions, a lot of energy is wasted and scientists have been working on reducing this wasted energy.
What breakthroughs have been made?
Lockheed Martin, an American arms company, has announced that they have made huge steps forward and have promised a nuclear fusion reactor, small enough to put onto a lorry, within 10 years. Their announcement has been met with a lot of scepticism by the scientific community due to a lack of data but Lockheed appear to be serious about their pledge.
It may seem too good to be true.
But, cast your mind back 10 years to 2004, we all shouted at our modems and suitcase sized computers — did the iPhone really seem within our reach?
Why do we need fusion?
We all know that fossil fuels are running out and governments are desperately looking for alternatives. Renewables like wind and solar remain unreliable so attention is being focussed on nuclear. However, nuclear fission produces dangerous nuclear waste that remains dangerous for hundreds of years and is incredibly difficult to store safely. The chain reaction involved in fission can get out of control meaning that the danger of a meltdown is always present. In addition, the uranium used in fission is a finite resource and will run out just like fossil fuels eventually. Fusion requires hydrogen which, although finite is a lot more readily available than uranium; doesn’t use a chain reaction so it can’t go into meltdown and produces nuclear waste that is recyclable within 100 years. The advantages of fusion energy are evident and we must hope that fusion energy is not too far away from being viable.
Image courtesy of Chris k50 via Flickr