Does the radioactivity of depleted uranium increase over time?
Yes and no. Uranium is a radioactive material with two primary isotopes, U235 and U238. These isotopes decay at a constant rate that has a half-life (i.e., time for the activity to reduce by half) greater than 100 million years. No significant change would be observed in the radiation emitted from these isotopes during a typical 75-year lifetime. However, the buildup of daughter products from the decay of these isotopes does increase the total radiation emitted from the material. In the radioactive decay process, an atom transforms by emitting radiation in the form of particles or energy. Uranium undergoes radioactive decay very slowly. The half-life for U238 is 4.5 billion years. After one half-life, a container that originally held 10,000 kg of pure U238 would be reduced to 5,000 kg of U238, along with approximately 5,000 kg of associated daughter products. Many of these daughter products are also unstable and undergo further radioactive decay until they transform into a stable isoto
