Uranium Basics

An infinitesimal quantity of natural uranium is ingested in the body on a daily basis. It passes through the body with minimal effects. It is absorbed very poorly in the gastrointestinal tract (only 2% absorption). Approximately 10 nanograms (a nanogram is 1 one-billionth of a gram) is excreted daily in human urine.

Once mined, uranium is refined into concentrated packets of almost pure uranium. It is this highly concentrated “natural” uranium which is processed to produce enriched uranium. The enrichment process increases the isotope U235 concentration to create Enriched Uranium which is more easily fissionable for use in nuclear weapons and reactors. This process also creates depleted uranium (DU) as a byproduct.

All uranium whether “natural”, “depleted” or “enriched” is a chemical and radiological toxic substance emitting alpha, beta and gamma particles. All forms of uranium differ from each other by only a fraction of one percent. Both natural and depleted uranium are over 99% composed of the isotope U238. The ratio of isotope U238/U235 gives the unique signature that identifies whether the uranium is enriched, natural, or depleted.

Radioactivity (disintegrations per second) in 1 milligram of U-238 at Secular Equilibrium

In the course of one year, 1 milligram of uranium emits 390 million alpha particles, 780 million beta particles and associated gamma rays. This is over one billion high-energy, ionizing, radioactive particles and rays which can produce extensive biological damage.

The energy of a single alpha particle exceeds the amount required to damage important macromolecules such as DNA, RNA, enzymes and proteins. It does this by breaking molecular bonds and by chemical reactions, which alter or destroy the shape, organization, and function of these molecules.