1. How Do Nuclear Reactors Work?

An understanding of the basics of nuclear fission is needed to fully understand the processes that have led to the world’s three major commercial nuclear accidents. Nuclear power plants use heat generated in the atomic fission to generate steam and produce electrical power. The fuels for reactors are usually radioactive isotopes of uranium and plutonium. When these materials undergo fission, they break down into smaller elements and release energy and subatomic particles. Importantly, neutrons released by fission are used to generate the fission of additional atoms and give rise to atomic chain reactions. The trick for power plant operators is to ensure that the number of neutrons generated by fission equals the number used to continue fission and those lost from the system. In addition, the neutrons must be significantly slowed so that they can cause the fission of other atoms. To do this, nuclear reactors use moderators such as graphite, water, and heavy water.