Fission and Fusion

• Nuclear fission is the splitting of a large and unstable nucleus (e.g. uranium or plutonium)
• Spontaneous fission is rare ; usually, for fission to occur the unstable nucleus must first absorb a neutron
• The nucleus undergoing fission splits into two smaller nuclei, roughly equal in size, and emits two or three neutrons plus gamma rays
• Energy is released by a fission reaction
• All of the fission products have kinetic energy
• The neutrons from fission reactions may go on to start a chain reaction
• The chain reaction of nuclear fission is controlled in a nuclear reactor to control the energy released
• Nuclear fusion is the joining of two light nuclei to form a heavier nucleus
• In this process of nuclear fusion some of the mass may be converted into the energy of radiation