Search results
Results from the WOW.Com Content Network
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 .
Plutonium-238 has a half-life of 87.74 years [11] and emits alpha particles. Pure 238 Pu for radioisotope thermoelectric generators that power some spacecraft is produced by neutron capture on neptunium-237 but plutonium from spent nuclear fuel can contain as much as a few percent 238 Pu, originating from 237 Np, alpha decay of 242 Cm, or (n,2n ...
The odd numbered fissile plutonium isotopes present in spent nuclear fuel, such as Pu-239, decrease significantly as a percentage of the total composition of all plutonium isotopes (which was 1.11% in the first example above) as higher and higher burnups take place, while the even numbered non-fissile plutonium isotopes (e.g. Pu-238, Pu-240 and ...
The "reactor-grade" plutonium produced by a regular LWR burnup cycle typically contains less than 60% Pu-239, with up to 30% parasitic Pu-240/Pu-242, and 10–15% fissile Pu-241. [124] It is unknown if a device using plutonium obtained from reprocessed civil nuclear waste can be detonated, however such a device could hypothetically fizzle and ...
Pu-239 is produced artificially in nuclear reactors when a neutron is absorbed by U-238, forming U-239, which then decays in a rapid two-step process into Pu-239. It can then be separated from the uranium in a nuclear reprocessing plant. Weapons-grade plutonium is defined as being predominantly Pu-239, typically about 93% Pu-239. [21]
plutonium containing 238 Pu, 239 Pu, 240 Pu, 241 Pu, and 242 Pu, minor actinides including 237 Np, 241 Am, 243 Am, curium isotopes, and perhaps californium; reprocessed uranium containing 236 U and other isotopes; tritium; activation products of neutron capture by the reactor or bomb structure or the environment
However, one study on plutonium in marine sediments indicates that the atomic bomb fallout accounts for 66% of the 239 Pu and 59% 240 Pu in the English Channel. In contrast, nuclear reprocessing contributes the majority of the 238 Pu and 241 Pu in the Earth's oceans, whereas nuclear weapons testing is responsible for only 6.5% and 16.5% of ...
238 Pu has become the most widely used fuel for RTGs, in the form of plutonium(IV) oxide (PuO 2). [34] However, plutonium(IV) oxide containing a natural abundance of oxygen emits neutrons at the rate of roughly 2.3 × 10 3 n/sec/g of plutonium-238. This emission rate is relatively high compared to the neutron emission rate of plutonium-238 metal.