Explain how a nuclear power station uses nuclear fission to generate electricity.

Eduqas A-Level Physics — 3.6 Nuclear energy · Explain · 5 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Nuclear power stations generate about 15% of the UK's electricity. They use uranium as a fuel instead of burning fossil fuels.

Model answer (5 marks)

Nuclear fission is the splitting of a heavy nucleus such as uranium.
A neutron is absorbed by the uranium nucleus, causing it to split.
The fission reaction releases a large amount of energy as heat and produces additional neutrons.
The heat is used to boil water, producing steam.
The steam drives a turbine, which turns a generator to produce electricity.

Examiner tips

Use the exact sequence of steps; include the neutron absorption and heat generation.
Show the link between heat, steam, turbine and generator.
Use the term ‘fission’ and ‘uranium’ explicitly.
Mention that the extra neutrons sustain the chain reaction.

Common mistakes

Confusing fission with fusion.
Omitting the role of the turbine and generator.
Using vague terms like ‘energy’ without specifying heat or steam.

Mark scheme (5 marks)

Nuclear fission is the splitting of a large/heavy nucleus (such as uranium)
A neutron is absorbed by the uranium nucleus to trigger fission
Fission releases a large amount of energy (as heat/thermal energy) and further neutrons
The heat released is used to boil water to produce steam, which drives a turbine
The turbine drives a generator which produces electricity

Key terms in this question

nuclear fission