IEER
Properties of Plutonium Isotopes
The plutonium isotopes listed below are "fissionable," which means that the nuclei can be split
into two fragments, called fission products. In addition to being fissionable, plutonium-239 and
plutonium-241 are "fissile" - that is, they can be split by neutrons of very low (ideally zero)
energy. This means that they can be assembled into a critical mass, and hence can sustain a
chain reaction without an external source of neutrons. To help you learn more about the
properties of Plutonium, check out this
worksheet on Plutonium!
Important Radiological Properties of Plutonium Isotopes
|
Pu-238 |
Pu-239 |
Pu-240 |
Pu-241 |
Pu-242 |
| Half-life (in years) |
87.74 |
24,110 |
6,537 |
14.4 |
376,000 |
| Specific activity (curies/gram) |
17.3 |
0.063 |
0.23 |
104 |
0.004 |
| Principal decay mode |
alpha |
alpha |
alpha and some spontaneous fission1 |
beta |
alpha |
| Decay energy (MeV) |
5.593 |
5.244 |
5.255 |
0.021 |
4.983 |
| Radiological hazards |
alpha and weak gamma |
alpha and weak gamma |
alpha and weak gamma |
beta and weak gamma2 |
alpha and weak gamma |
| How isotope is produced |
nuclear reactors |
nuclear reactors |
nuclear reactors |
nuclear reactors |
nuclear reactors |
| Main uses |
Production of thermoelectric power used in nuclear weapons, satallites, and
heart pacemakers |
Fissile material for nuclear weapons, and for the production of
energy |
none |
none |
none |
Source: CRC Handbook of Chemistry and Physics, 1990-1991. Various sources give
slightly different figures for half-lives and energies.
1Source of neutrons causing added radiation dose to workers in nuclear
facilities.
2Plutonium-241 decays into Americium-241, which is an intense gamma emitter.
Go to worksheet on Plutonium.
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Last Updated April 17, 1996