Search results
Results from the WOW.Com Content Network
For instance, 3.6 kg of plutonium-238 undergoes the same number of radioactive decays per second as 1 tonne of plutonium-239. Since the morbidity of the two isotopes in terms of absorbed radioactivity is almost exactly the same, [ 55 ] plutonium-238 is around 275 times more toxic by weight than plutonium-239.
Plutonium-238 (238 Pu or Pu-238) is a radioactive isotope of plutonium that has a half-life of 87.7 years. Plutonium-238 is a very powerful alpha emitter ; as alpha particles are easily blocked, this makes the plutonium-238 isotope suitable for usage in radioisotope thermoelectric generators (RTGs) and radioisotope heater units .
The isotope produces 0.57 watts of thermal power per gram of 238 Pu. [5] Soviet missions have used other isotopes, such as the polonium-210 heat source used in the Lunokhod lunar rovers. [6] [7] With a half-life of 138.376 days, polonium-210 produces more thermal power per unit mass, but is suitable only for shorter duration missions.
Less than a formula quantity of strategic special nuclear material but more than 1,000 grams of uranium-235 (contained in uranium enriched to 20 percent or more in the U-235 isotope) or more than 500 grams of uranium-233 or plutonium-239, or in a combined quantity of more than 1,000 grams (2.2 pounds) when computed by the equation grams ...
The energy source for each device was a rod of plutonium-238 providing a thermal power of approximately 1250 W. [22] This fuel capsule, containing 3.8 kilograms (8.4 lb) of plutonium-238 in oxide form (44,500 Ci or 1.65 PBq), was carried to the Moon in a separate fuel cask attached to the side of the Lunar Module. The fuel cask provided thermal ...
The neutrons are supplied by the nuclear reactor in a way similar to production of plutonium 239 Pu from 238 U feedstock: target rods of the 6 Li feedstock are arranged around a uranium-fueled core, and are removed for processing once it has been calculated that most of the lithium nuclei have been transmuted to tritium.
talk. edit. Plutonium (94 Pu) is an artificial element, except for trace quantities resulting from neutron capture by uranium, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. It was synthesized long before being found in nature, the first isotope synthesized being plutonium-238 in 1940.
For one thing, it may operate at higher burnups and therefore increase the relative abundance of the non-fissile, but fertile, isotopes plutonium-238, plutonium-240, and plutonium-242. [34] Unlike PUREX reprocessing, the IFR's electrolytic reprocessing of spent fuel does not separate out pure plutonium. Instead, it is left mixed with minor ...