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Uranium-238. Uranium-238 (238U or U-238) is the most common isotope of uranium found in nature, with a relative abundance of 99%. Unlike uranium-235, it is non-fissile, which means it cannot sustain a chain reaction in a thermal-neutron reactor. However, it is fissionable by fast neutrons, and is fertile, meaning it can be transmuted to fissile ...
Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235 U) has been increased through the process of isotope separation.Naturally occurring uranium is composed of three major isotopes: uranium-238 (238 U with 99.2732–99.2752% natural abundance), uranium-235 (235 U, 0.7198–0.7210%), and uranium-234 (234 U, 0.0049–0.0059%).
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] U-233 is produced from thorium-232 by neutron capture. The U-233 produced ...
As of March 10, 2011, there were 94 Superfund sites on the National Priorities List in California. [2] Three additional sites have been proposed for entry on the list. [2] Twelve sites have been cleaned up and removed from the list. [2] One site was proposed for entry and then removed.
Since 238 U has a much longer half-life than the lighter isotopes, DU is about 40% less radioactive than natural uranium. [2] [13] [14] Most of the alpha radiation comes from 238 U and 234 U [notes 1] whereas beta radiation comes from decay products 234 Th and 234 Pa that are formed within a few weeks.
Isotopes of uranium. Uranium (92 U) is a naturally occurring radioactive element (radioelement) with no stable isotopes. It has two primordial isotopes, uranium-238 and uranium-235, that have long half-lives and are found in appreciable quantity in Earth's crust. The decay product uranium-234 is also found. Other isotopes such as uranium-233 ...
Natural uranium (NU or Unat[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. Natural uranium can be used to fuel ...
By 1960, when he sold the last of his uranium stock, he had made over $100 million in cash from the uranium business. [ 6 ] From 1961 to 1976, Hirshhorn lived in a three-story Norman chateau in a 22-acre (89,000 m 2 ) estate at the summit of Round Hill, a 550-foot (170 m) rise in north-central Greenwich , Connecticut, with a view of the ...