About Nuclear Energy
Why do we need electricity?
What happens when you press a light switch, turn on the television or start up your PlayStation?
All these things need energy in the form of electricity so you can use them.
How do we make electricity?
There are lots of different ways of making electricity:
- We can burn fossil fuels such as coal, oil and gas
- We can use renewable sources such as solar, hydro and wind power
- We can use a metal called uranium to make nuclear power
Electricity in the future
Why is making electricity becoming a problem?
One big problem is that the number of people living on Earth grows every year. Did you know that by 2050 there will be roughly 9.6 billion people on Earth! So we need more and more energy to help power everyone’s daily lives.
Scientists know that continuing to burn fossil fuels produces CO2 – a greenhouse gas.
We also know that in order to make electricity from the sun, wind or water, which is dependent on environmental conditions, we need to have a backup supply of energy which ensures there is a consistent supply.
We call this baseloading, which is a key advantage of nuclear power!
Most electricity in the world is created by a steam turbine:
1. Steam is created by heating water until it boils
2. The steam is used to turn the blades of a turbine so that it spins
3. The spinning turbine turns a generator creating electricity
4. The electricity goes to transformers which produces the correct voltage, which gives us a constant supply of power!
The big difference is where the source of the heat comes from, which boils the water to create the steam. At a nuclear power plant, heat is created when uranium atoms are split by a process called ‘nuclear fission’.
What is nuclear fission?
The nucleus of a uranium atom contains both protons and neutrons. When a moving neutron hits the nucleus of a uranium atom, it splits it into several smaller fragments and releases more neutrons.
These neutrons hit more uranium nuclei repeating the cycle in what is called a chain reaction. This produces a large amount of heat energy.
The heat energy produced is used to boil the water, to make steam, to turn the turbine, that generates electricity- simple!
Why is uranium so good in making electricity?
Electricity made from uranium (nuclear energy) is very useful because:
1. Nuclear energy doesn’t produce any CO2 which could damage the natural world.
2. Nuclear energy gives us electricity whenever we need it.
To make nuclear power, uranium is mined from the Earth, just like coal and copper. We must then add a chemical called fluorine to uranium. This turns the uranium into uranium hexafluoride (UF6) which is a yellow powder. The yellow powder is turned into a gas in large ovens.
Heating the powder turns it into a gas. The powder is then ready to be enriched by Urenco so it can be turned into a nuclear fuel.
The two types of isotopes which make up uranium are called U235 and U238. We need uranium to contain lots more U235 for nuclear fission to work. So how do we increase the amount of U235 in uranium? This is where ‘enrichment’ comes in!
Urenco uses centrifuge technology to enrich uranium. To enrich means to strengthen.
If you had a chocolate cake for example, and you continued to add coco powder, you would be strengthening the chocolate flavour.
So what is the enrichment process?
1. Urenco feeds the UF6 gas into a centrifuge.
(A centrifuge is like two tubes facing up, a small tube inside a big tube.)
2. The centrifuge spins very quickly which separates the two isotopes. The U238 is heavier than the U235, which means that the U238 is pushed to the sides of the tube – a bit like when you’re pressed into your seat on a rollercoaster.
The U235 stays in the middle of the tube because it is not as heavy.
A pipe takes the UF6 gas from the middle of the centrifuge’s tube, to another centrifuge where the same thing happens again.
The uranium gas goes through lots of centrifuges, with the same thing happening over and over again.
3. The gas which has gone through the all the centrifuges has now been ‘enriched’. This means it now has the right balance of isotopes to make the best fuel possible.
Urenco only needs to enrich by 5% in order to produce nuclear energy!
4. The enriched gas goes into a big cylinder. The gas is cooled to become a solid material.
Did you know? One nuclear fuel pellet about the size of your fingernail provides as much energy as a lorry full of coal!
What happens next to
the enriched uranium?
This solid material is transported to fuel fabricators who make it into small pellets.
The pellets then go to the nuclear power station, which provide a secure source of low carbon energy – generating electricity for homes, schools, hospitals, offices and industries around the world.
