Fermi's controlled nuclear reaction

• Fermi realised that every time a fission reaction occurred, 3 neutrons would be released.
• As only one neutron is required to start a reaction, this could cause a chain reaction and release a lot of energy.
• However, if not all of the neutrons caused reactions, and some were absorbed, a chain reaction could be controlled.
• In 1942, Fermi placed 22000 slugs of Uranium (50 tonnes worth) in an atomic pile in a squash field at Staggs Field, Chicago.
• He then inserted 40000 graphite bricks (400 tonnes worth) inside the pile as a moderator.
• Cadmium control rods were also used to control the reaction.
• He eventually found that his reaction was successful, and could self-sustainably generate 0.5 Watts of power.