Radioactivity Study Guide

Nuclear power is a significant energy resource because it generates electricity through the process of nuclear fission without producing carbon dioxide emissions during operation, helping to reduce greenhouse gases. It delivers a reliable, continuous supply of electricity. However, it also has several drawbacks: the major challenges are the production of radioactive waste, which remains hazardous and needs secure, long-term storage, and the possibility of severe accidents, despite strict safety measures. Public perception is often influenced by these risks and by high-profile incidents. As a result, nuclear power's overall viability involves balancing its low-carbon benefits with substantial challenges related to waste, safety, and public confidence.

Nuclear reactions involve changes within the nucleus of an atom and can release substantial amounts of energy. There are three primary types of nuclear reactions that serve as energy sources: nuclear fission, nuclear fusion, and radioactive decay. In nuclear fission, a heavy atomic nucleus splits into two or more smaller nuclei, releasing energy. This process is harnessed in nuclear power plants. Nuclear fusion, conversely, involves two light atomic nuclei combining to form a heavier nucleus, also releasing energy; this is the process that powers stars like our Sun. Radioactive decay is a spontaneous process where an unstable atomic nucleus transforms into a more stable one by emitting radiation and energy. While the energy released per decay event is small compared to fission or fusion, the cumulative energy from many such events can be significant, particularly in radioisotope thermoelectric generators (RTGs) used in spacecraft.