Nuclear Reactions

Nuclear Reactions

1. Three types of nuclear reactions

   • Radioactive decay: the emission of alpha and beta particles from unstable nuclei
   • nuclear fission: unstable nuclei split to form 2 daughter nuclei
   • nuclear fusion: small nuclei are joined to form larger ones

2. Nuclear FISSION

   • A neutron is absorbed by a uranium-235 nucleus which causes it to split into 2 smaller nuclei and release 2 neutrons which can then make other uranium-235 nuclei split in a chain reaction

3. Difference between nuclear fusion / fission

   • Nuclear fission is the splitting of nuclei and fusion is the joining of nuclei. Both release lots of energy.

4. Nuclear fusion

   • The creation of larger nuclei from smaller ones as happens in stars
   • why this doesn't happen at low temperatures or pressures
     • At low temperatures and pressures there is not enough energy to overcome the electrostatic repulsion between nuclei.
   • why is it impractical to make a nuclear fusion power station
     • At the moment any reactors we have made have used more energy creating the high temperatures and pressures needed to overcome this electrostatic repulsion than they have created by nuclear fusion