Nuclear materials refer to substances that can undergo nuclear reactions, such as fission or fusion. These materials include isotopes like uranium and plutonium, which are commonly used in nuclear reactors and weapons. They can release large amounts of energy, making them powerful but also requiring careful handling and regulation due to their potential hazards. In addition to uranium and plutonium, other nuclear materials include thorium and various isotopes used in medical applications, such as cobalt-60. The management of these materials is crucial for safety, as they can pose risks of radiation exposure and environmental contamination if not properly controlled.