Fission and Fusion
5 marks · NormalFor many years, scientists have been working on using nuclear reactions as a source of energy. Nuclear fission and fusion are both involved in producing energy in different ways.
State what is meant by nuclear fission and identify the type of material most commonly used for fission in a power plant.
Explain one major reason why nuclear fusion does not currently power electricity stations on Earth, even though it is the source of energy in stars.
Describe one radioactive product that is produced by nuclear fission.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) —
(b) —
(c) —
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correctly states that nuclear fission is the splitting of a large nucleus (or atom) into smaller nuclei, releasing energy.
B2 (a) · 1 mark · Identifies uranium-235 as the most common fission fuel in power plants (or U-235, uranium).
B1 (b) · 1 mark · Gives a correct reason for fusion difficulty: very high temperature or high pressure needed due to electrostatic repulsion between nuclei.
B2 (b) · 1 mark · Links reason to inability to overcome electrostatic repulsion or 'Coulomb barrier' at low temperature/pressure.
B1 (c) · 1 mark · Names one radioactive daughter product of fission (e.g., krypton-89, barium-144 or any valid fission product).
Worked solution
a) Nuclear fission is the splitting of a large atomic nucleus into two smaller nuclei and some neutrons, releasing energy. The most common material used is uranium-235.
b) Fusion does not currently power Earth-based stations because it requires extremely high temperatures and/or pressures to overcome the electrostatic repulsion between positively charged nuclei, which is only achieved in stars due to their immense gravity and temperature.
c) One radioactive product of fission is krypton-89 (or accept barium-144, etc.).