Nuclear Fusion

• Nuclear fusion is the combining of small nuclei to form a larger nucleus
• The amount energy released per nucleon through fusion is greater then that released through fission
• mass of reactants > mass of product
• mass of combined particles > mass of element

  • because mass is lost through the use of the binding energy that holds the subatomic particles together
• Factor affecting nuclear fusion

  • nuclei are repelled from one another because of their electrostatic positive charges. To overcome this the nuclei must travel at high speeds so that they have enough kinetic energy to overpower the repulsion and become close enough for a strong nuclear force to act
• The higher the binding energy the more stable the nucleus
• Binding energy is the energy required to hold the subatomic particles of an atom together and vice versa the energy required to seperate the nucleus into individual particles
• Facts:

  • Smaller nuclei have smaller binding energy and are easier to break
  • elements with a mass number 40-80 are the most stable nuclei as they have the highest binding energy
• Nuclear fusion Reactors

  • the energy released per nucleon is greater then that of fission as a greater percentage of mass is transformed.
  • Important as massive amounts of energy can be obtained without producing radioactive by-products
• Reasons for no present Fusion Reactors:

  • replicating the suns reactions are difficult as extreme densities, pressures and temperatures are required