Nuclear Fusion

Key Stage 4

Meaning

Nuclear fusion is a process in which two small atomic nuclei join together to become a larger nucleus.

About Nuclear Fusion

In a nuclear fusion reaction the products have less mass than the reactants as some of the mass is converted into energy in the process due to the Mass-Energy Equivalence.

For a fusion reaction to occur the two nuclei must have enough kinetic energy to overcome the electrostatic force of repulsion between the positively charged nuclei.

To provide enough kinetic energy to the nuclei the substance must be heated to a temperature of several million degrees Celsius.

Nuclear fusion occurs naturally in the centre of a Star due to the high temperatures and pressure.

Nuclear fusion is possible in laboratories on Earth but it cannot be sustained for long periods of time to produce enough energy to be useful as an energy resource.

Nuclear fusion in laboratories on Earth must be done at much higher temperature than in the centre of Stars because the centre of Stars is a much higher pressure so nuclei collide more often.

Nuclear Fusion Reactions

Fusion of a Tritium and a Deuterium nucleus produces a Helium nucleus. \({}_1^2H + {}_1^3H \rightarrow {}_2^4He + {}_0^1n\) This is the most common pathway for nuclear fusion in Stars as the neutron goes on to be captured by a Hydrogen nucleus to become Deuterium or captured by a Deuterium nucleus to become a Tritium nucleus.

Fusion of two Hydrogen nuclei (protons) produces a Deuterium nucleus. \({}_1^1H + {}_1^1H \rightarrow {}_1^2H + {}_{-1}^0\beta\)

Fusion of a Hydrogen nucleus (proton) and a Deuterium nucleus produces a Tritium nucleus. \({}_1^1H + {}_1^2H \rightarrow {}_1^3H + {}_{-1}^0\beta\)

Fusion of two Deuterium nuclei produces a Helium nucleus. \({}_1^2H + {}_1^2H \rightarrow {}_2^4He\)

Fusion of a Hydrogen nucleus (proton) and a Tritium nucleus produces a Helium nucleus. \({}_1^1H + {}_1^3H \rightarrow {}_2^4He\)

References

AQA

Nuclear fusion, page 108, GCSE Physics, Hodder, AQA

Nuclear fusion, page 244, GCSE Chemistry, Hodder, AQA

Nuclear fusion, pages 106-107, GCSE Physics; Third Edition, Oxford University Press, AQA

Nuclear fusion, pages 140, 141, 318, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA

Nuclear fusion, pages 187-8, GCSE Combined Science Trilogy 2, Hodder, AQA

Nuclear fusion, pages 49, 100, GCSE Physics; The Revision Guide, CGP, AQA

Nuclear fusion; in stars, page 252, GCSE Physics, Hodder, AQA

Edexcel

Nuclear fusion, page 58, GCSE Physics; The Revision Guide, CGP, Edexcel

Nuclear fusion, pages 110, 114-115, GCSE Physics, Pearson Edexcel