Uranium can be found in low levels in all rock, soil and water. It occurs in most rocks in concentrations of 2 to 4 parts per million and is also found in the oceans, at an average concentration of 1.3 parts per billion.
- Uranium is a heavy metal, comparable to lead.
- Uranium is as common as tin, tungsten and molybdenum, and about 40 times as common as silver.
- Most uranium exists as its isotope U-238 (99.2745 %). The rest is U-235 (0.72%) and U-234 (0.0055%).
Uranium and Nuclear Power
- The rare uranium isotope U-235 is the fuel most widely used by nuclear plants for fission because its atoms are easily split apart in the reactor.
- One ton of uranium can produce more than 40 million kilowatt hours of electricity, equal to 16,000 tons of coal or 80,000 barrels of oil.
- There are a number of areas around the world where the concentration of uranium in the ground is sufficiently high that it can be economically extracted for nuclear fuel. Such concentrations are called ore.
- Radioactivity is the term used to describe the natural process by which some atoms of unstable isotopes of elements spontaneously disintegrate, emitting particles and energy as they transform into more stable atoms.
- This stabilizing process emits alpha and beta particles and sometimes gamma radiation from the nucleus, each of which is energetic enough to break chemical bonds and able to damage or destroy living cells.
- Each radioactive element, or radionuclide, has a characteristic half-life, which is the time it takes for one half of the atoms of a particular radionuclide to disintegrate (or decay) into another nuclear form.
- The longer the half-life of a radionuclide, the less radioactive it is for a given mass.
Radioactivity of Uranium
- All isotopes of uranium are radioactive, with most having extremely long half-lives.
- Uranium and its decay products primarily emit alpha particles that have little ability to penetrate through membranes, such as skin or even paper. Lower levels of both beta and gamma radiation also are emitted.
- Long-term studies of regions with uranium recovery show no increased risk of cancer mortality from living nearby such facilities.