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Uranium-235 makes up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a fission chain reaction. It is the only fissile isotope that is a primordial nuclide or found in significant quantity in nature. Uranium-235 has a half-life of 703.8 million years.
Finely divided uranium metal presents a fire hazard because uranium is pyrophoric; small grains will ignite spontaneously in air at room temperature. [12] Uranium metal is commonly handled with gloves as a sufficient precaution. [143] Uranium concentrate is handled and contained so as to ensure that people do not inhale or ingest it. [143]
Uranium slowly accumulates in several organs, such as the liver, spleen, and kidneys. The World Health Organization has established a daily "tolerated intake" of soluble uranium salts for the general public of 0.5 micrograms per kilogram (3.5 × 10 −6 gr/lb) body weight, or 35 micrograms (0.00054 gr) for a 70 kilograms (150 lb) adult.
Uranium-235 (235 U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exists in nature as a primordial nuclide. Uranium-235 has a half-life of 703.8 million years.
Uranium-235 fissile isotope: 144,000,000 [1] 1,500,000,000: Natural uranium ... Nickel–metal hydride (NiMH), low power design as used in consumer batteries [29] 0.4:
Natural uranium (NU or U nat [1]) is uranium with the same isotopic ratio as found in nature. It contains 0.711% uranium-235 , 99.284% uranium-238 , and a trace of uranium-234 by weight (0.0055%). Approximately 2.2% of its radioactivity comes from uranium-235, 48.6% from uranium-238, and 49.2% from uranium-234.
Uranium metal can also be made through electrolysis of KUF 5 or UF 4, dissolved in a molten CaCl 2 and NaCl. Very pure uranium can be produced through the thermal decomposition of uranium halides on a hot filament. The uranium isotope 235 U is used as the fuel for nuclear reactors and nuclear weapons. It is the only isotope existing in nature ...
Natural uranium is made weapons-grade through isotopic enrichment. Initially only about 0.7% of it is fissile U-235, with the rest being almost entirely uranium-238 (U-238). They are separated by their differing masses. Highly enriched uranium is considered weapons-grade when it has been enriched to about 90% U-235. [citation needed]