• Question: If you could easily generate the heat needed for nuclear fusion then would we use it on a larger scale? Because I thought that nuclear fusion created less waste products than fission and also how do we utilise the energy created through both of these reactions? And what is the most common element for fusion/fission? Is it Plutonium, Uranium or another?

    Asked by corange to Amy, Drew, Julia, Kimberley, Sara on 22 Jun 2011.
    • Photo: Drew Rae

      Drew Rae answered on 20 Jun 2011:

      Hi Corange. The normal way to get energy from a power station is to heat up water, and then use the steam to turn a large turbine (like a paddle-wheel or screw). The turbine spins wire inside a magnetic field, which creates electricity.

      If we could get fusion working economically it would produce some radiation, but otherwise be very clean. Nuclear fusion doesn’t need radio-active material. For fission, the most common element used is Uranium, although Plutonium is used too.

    • Photo: Amy MacQueen

      Amy MacQueen answered on 21 Jun 2011:

      I guess we would – but it would probably throw up some other issues. Fusion does create less waste products but the radiation and thermal damage to the reactor vessel would be problematic from a practical reactor standpoint.

    • Photo: Julia Griffen

      Julia Griffen answered on 21 Jun 2011:

      I agree with you… A fusion nucear power plant would be the option… By calculations one fusion reactor would be enough energy for the whole world for the next 50 years!!! (or something like like basically along time!)

      SO why dont we have a fusion reactor? SO we’ve already said it can generate alot of energy.. we dont have the science or technology at present to capture and hold that amount of energy safely!! Especially not on a large scale.

      If they could though.. it would be a possible answer to fossil fuels etc.. Not sure on the finner deatils though.. hope this has given you pointers int he right direction.

    • Photo: Sara Imari Walker

      Sara Imari Walker answered on 22 Jun 2011:

      Hi Corange! Great question! There is an important distinction between fusion and fission.

      Fission occurs when a heavy and unstable atom splits into to smaller atoms. Uranium and Plutonium are two examples of common elements that undergo fission with a short half-life (i.e. they do it fairly easily). Both have high atomic number and are highly unstable – see here https://calciumj11.imascientist.org.uk/2011/06/why-has-the-perodic-table-of-elements-only-got-a-certain-number-of-elements-why-arent-their-unlimited for an explanation of why elements with large atomic mass are unstable.

      Fusion on the other hand is basically the opposite process. Fusion occurs when two light atoms’ nuclei fuse together to make a heavier nucleus.

      Fission can happen spontaneously. We have also figured out how to make it happen for example by inducing an unstable uranium atom to decay causing a chain reaction of decays. A lot of energy is released in the process. We have harnessed this energy to make atomic bombs and nuclear power plants.

      In contrast humans have NOT harnessed fusion. Fusion is much much more difficult given the energies required to get it going. You have to get the two atoms under such high temperature and pressure that you can bring their two nuclei together despite the electromagnetic repulsion force keeping them apart (remember nuclei have protons which have a positive charge). Fusion of hydrogen happens all the time in the Sun, but the interior of the Sun is under immense pressure and is at 15 million Kelvin! Those are not conditions we can easily reproduce.

      So why are we interested in fusion at all then? Well for one it would be a major energy source if we could find a way to do “cold” fusion (i.e. at a temp color than the center of the Sun). Also,with fusion there is no possibility of runaway heat build-up or large-scale release of radioactivity, there is little or no atmospheric pollution, the power source comprises light elements (like hydrogen or helium) in small quantities which are easily obtained and largely harmless, the waste products are short-lived in terms of radioactivity, and fusion doesn’t really make for good weapons. So its essentially safe nuclear power.

      Maybe one day we will harness it!! That would be amazing!!