uranium 238
Noun: - The most abundant isotope of uranium: Uranium 238 is a specific, naturally occurring form of the element uranium. It is characterized by having 92 protons and 146 neutrons in its nucleus, giving it an atomic mass of 238. - A non-fissile but fertile material: While uranium 238 itself is not easily split (fissionable) in standard nuclear reactors, it can absorb neutrons to transform into other elements, most notably plutonium 239, which is fissionable.
Uranium 238 is used primarily in scientific and industrial contexts related to nuclear physics, energy, and geology. - It is the primary component of natural uranium, making up over 99% of its mass. - It serves as a fertile material for breeding fissile plutonium 239 in nuclear reactors. - It is used in radiation shielding and armor-piercing ammunition due to its high density.
- Scientific Context:
- Uranium 238 has a very long half-life, over four billion years.
- In a breeder reactor, uranium 238 absorbs a neutron to eventually become plutonium 239.
- Industrial/Geological Context:
- The ore was analyzed and found to consist largely of uranium 238.
- Depleted uranium, primarily composed of uranium 238, is used for heavy tank armor.
- "To breed from uranium 238": Refers to the process of transmuting uranium 238 into a fissile material like plutonium 239.
- The reactor was designed to breed fissile fuel from uranium 238.
- "The uranium 238 decay chain": Refers to the series of radioactive decays by which uranium 238 transforms into stable lead (Pb-206).
- Scientists study the uranium 238 decay chain to date ancient rocks.
- Depleted Uranium (DU): A byproduct of uranium enrichment, consisting mainly of uranium 238 with most of the fissile U-235 removed. It is used for its density and metallurgical properties.
- Uranium 235 (U-235): The fissile isotope of uranium used as fuel in most nuclear reactors and weapons. It is much rarer than U-238.
- Plutonium 239 (Pu-239): A fissile isotope produced when uranium 238 captures a neutron. It is used as nuclear fuel and in weapons.
- U-238: The standard scientific abbreviation.
- Depleted uranium (in its primary form): When referring to the material after enrichment.
- Fertile material: Describing its property of being transmutable into fissile fuel.
This term refers strictly to the specific isotope with mass number 238. It is distinct from: - Uranium (the element): The general chemical element (symbol U). - Enriched uranium: Uranium processed to have a higher percentage of U-235. - Fissile uranium: Typically refers to uranium 235, which readily undergoes fission. Uranium 238 is non-fissile under normal reactor conditions.
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the commonest isotope of uranium; it is not fissionable but when irradiated with neutrons it produces fissionable plutonium 239
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