Nuclear Fusion (OCR GCSE Physics A (Gateway)): Revision Note

Nuclear Fusion

• Small nuclei can react to release energy in a process called nuclear fusion

• Nuclear fusion is defined as:

  When two light nuclei join to form a heavier nucleus

• This process requires extremely high temperatures to maintain

  • This is why nuclear fusion has proven very hard to reproduce on Earth

• Stars use nuclear fusion to produce energy

• In most stars, hydrogen atoms are fused together to form helium and produce lots of energy

Two hydrogen nuclei are fusing to form a helium nuclei

• The energy produced during nuclear fusion comes from a very small amount of the particle’s mass being converted into energy

• Albert Einstein described the mass-energy equivalence with his famous equation:

E = m × c²

• Where:

  • E = energy released from fusion in Joules (J)

  • m = mass converted into energy in kilograms (kg)

  • c = the speed of light in metres per second (m/s)

• The amount of energy released during nuclear fusion is huge:

  • The energy from 1 kg of hydrogen that undergoes fusion is equivalent to the energy from burning about 10 million kilograms of coal

• Designing a working fusion power station which produces more power than it uses is a major goal in engineering

  • ITER in France is currently the best performing fusion power station, almost giving out as much energy as it requires to power it

• For fusion in a power station, deuterium and tritium, heavy isotopes of hydrogen are used

The fusion of deuterium and tritium to form helium with the release of energy