Discussion of radioactivity and radiation, uranium and radioactivity, radiological health risks of uranium isotopes and decay products. Radioactivity is the term used to describe the natural process by which some atoms spontaneously disintegrate, emitting both particles and energy as they transform into different, more stable "Radiation in radioactive dating." This process, also called radioactive decay, occurs because unstable isotopes tend to transform into a more stable state.
Radioactivity is measured in terms of disintegrations, or decays, per unit time. Common units of radioactivity are the Becquerel, equal to 1 decay per second, and the Curie, equal to 37 billion decays per second.
Radiation refers to the particles or energy released during radioactive decay. The radiation emitted may be in the form of particles, such as neutrons, alpha particles, and beta particles, or waves of pure energy, such as gamma and X-rays.
Each radioactive element, or radionuclide, has a characteristic half-life. Half-life is a measure of the time it takes for one half of the atoms of a particular radionuclide to disintegrate or decay into nuclear form. Half-lives vary from millionths of a second to billions of years. Because radioactivity is a measure of the rate at which a radionuclide decays for example, decays per secondthe longer the half-life of a radionuclide, the less radioactive it is for a given mass.
Everyone is exposed to radiation on a daily basis, primarily from naturally occurring cosmic rays, radioactive elements in the soil, and radioactive elements incorporated in the body. Man-made sources of radiation, such as medical X-rays or fallout from historical nuclear weapons testing, also contribute, but to a lesser extent.
All isotopes of uranium are radioactive, with most having extremely long half-lives. Each radionuclide has a characteristic half-life.
The half live of uranium is about 4. Uranium atoms decay into other atoms, or radionuclides, that are also radioactive and commonly called "decay products.
The total activity level of uranium depends on the isotopic composition and processing history. A sample of natural uranium as mined is composed of In general, uranium and uranium pose a greater radiological health risk than uranium because they have much shorter half-lives, decay more quickly, and are thus "more radioactive.