What is nuclear fission?

What are the key learning points about nuclear fission?

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1. Nuclear fission is a process used to generate electricity in nuclear power stations. The fuel for nuclear fission is usually uranium-235.
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2. In a nuclear reactor, a neutron is absorbed by the uranium-235 nucleus.
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3. This causes the nucleus to become uranium-236, which is violently unstable.
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4. The uranium nucleus splits into two smaller 'daughter nuclei' and energy is released. In addition, two or three neutrons are also released.
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5. These can collide with other uranium nuclei to cause further fission reactions.
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6. This is known as a chain reaction.
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7. This energy is passed on to other components in the nuclear reactor, which can then be used to heat water to drive the turbines that turn the generators to generate electricity.
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8. The control rods absorb neutrons. They can be raised and lowered to control the rate of fission.

An uncontrolled reaction is the basis of an atomic bomb.

There are many political, social, environmental and issues relating to using nuclear energy to generate electricity.

The nuclear fission reaction does not release the , carbon dioxide.
A controlled nuclear fission reaction releases one million times more energy per kg of fuel than a chemical reaction such as burning coal, oil or gas.
Nuclear power creates well-paid employment opportunities for many people.
Modern reactor designs are extremely safe.

Many people have concerns about living close to nuclear power plants and the storage facilities used for radioactive waste because they fear radioactive material may leak out into the environment.
Major catastrophic incidents at nuclear power plants in Ukraine and Japan have caused huge economic, health and environmental damage to the area surrounding the power plant.
The mining, transport and purification of the uranium ore releases some greenhouse gases.
Like fossil fuels, nuclear fuels used for fission, such as uranium ore, are non-renewable energy resources since supplies will not last forever.
Decommissioning a nuclear power plant is extremely expensive and requires a skilled workforce.
The same technology used to make the fuel for use in reactors can be used to make nuclear weapons.
Radioactive waste is extremely dangerous and long lasting and expensive measures must be taken to store it.
In some cases, the waste is stored deep underground and must be kept for tens of thousands of years. Over time, this could leak and cause underground water and soil pollution. This is a particular worry in regions where there are earthquakes.