While the metal itself is radioactive, its high density makes it more effective than lead in halting radiation from strong sources such as radium.
The main risk of exposure to depleted uranium is chemical poisoning by uranium oxide rather than radioactivity (uranium being only a weak alpha emitter).
Later, a much more complicated and far more powerful type of fission/fusion bomb (thermonuclear weapon) was built, that uses a plutonium-based device to cause a mixture of tritium and deuterium to undergo nuclear fusion.
Such bombs are jacketed in a non-fissile (unenriched) uranium case, and they derive more than half their power from the fission of this material by fast neutrons from the nuclear fusion process.
The CANDU and Magnox designs are the only commercial reactors capable of using unenriched uranium fuel.
Fuel used for United States Navy reactors is typically highly enriched in uranium-235 (the exact values are classified).
In a breeder reactor, uranium-238 can also be converted into plutonium through the following reaction: The discovery and isolation of radium in uranium ore (pitchblende) by Marie Curie sparked the development of uranium mining to extract the radium, which was used to make glow-in-the-dark paints for clock and aircraft dials.
This left a prodigious quantity of uranium as a waste product, since it takes three tonnes of uranium to extract one gram of radium.This waste product was diverted to the glazing industry, making uranium glazes very inexpensive and abundant.Besides the pottery glazes, uranium tile glazes accounted for the bulk of the use, including common bathroom and kitchen tiles which can be produced in green, yellow, mauve, black, blue, red and other colors.and in the leather and wood industries for stains and dyes. Uranyl acetate and uranyl formate are used as electron-dense "stains" in transmission electron microscopy, to increase the contrast of biological specimens in ultrathin sections and in negative staining of viruses, isolated cell organelles and macromolecules.The discovery of the radioactivity of uranium ushered in additional scientific and practical uses of the element.The long half-life of the isotope uranium-238 (4.51×10 years) makes it well-suited for use in estimating the age of the earliest igneous rocks and for other types of radiometric dating, including uranium-thorium dating, uranium-lead dating and uranium-uranium dating.