GCSE Physics Unit 2 Revision (17)

Nuclear Fusion and Fission

• Nuclear fission - the splitting up of atomic nuclei
• Nuclear power stations and nuclear submarines are both powered by nuclear reactors.
• In a nuclear reactor, a controlled chain reaction takes place in which atomic nuclei split up and release energy in the form of heat. This heat is then simply used to heat water to drive a steam turbine. So nuclear reactors are really just glorified steam engines. The fuel that's split is usually uranium-235 or plutonium-239 (or both).
• The Chain Reactions
• If a slow-moving neutron gets absorbed by a uranium or plutonium nucleus, the nucleus can split.
• Each time a uranium or plutonium nucleus splits up, it spits out 2 or 3 neutrons, one of which might hit another nucleus, causing it to split also, and thus keeping the chain reaction going.
• When a large atom splits in…