This deep dive covers Nuclear Fusion Explained within Nuclear Fission & Fusion for GCSE Physics. Revise Nuclear Fission & Fusion in Atomic Structure for GCSE Physics with 13 exam-style questions and 25 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 3 of 18 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 3 of 18
Practice
13 questions
Recall
25 flashcards
☀️ Nuclear Fusion Explained
Nuclear fusion is the joining of two small, light nuclei to form a larger nucleus. The mass of the products is slightly less than the mass of the reactants — and this tiny mass difference is converted to an enormous amount of energy via E = mc².
Fusion powers the Sun and all stars. In the Sun, hydrogen nuclei (protons) fuse together to form helium, releasing energy as light and heat. On Earth, experiments use deuterium and tritium (isotopes of hydrogen) which fuse more easily and release 17.6 MeV per reaction.
The challenge is that nuclei are positively charged and repel each other strongly. To overcome this repulsion, they must be heated to over 100 million °C so they move fast enough to get very close. At these temperatures, matter exists as a plasma — no container material can hold plasma, so magnetic fields are used instead (tokamak reactors).