Plutonium-238
Plutonium-238 oxide pellet glowing from its decay heat | |
| General | |
|---|---|
| Symbol | 238Pu |
| Names | plutonium-238 |
| Protons (Z) | 94 |
| Neutrons (N) | 144 |
| Nuclide data | |
| Half-life (t1/2) | 87.7 years |
| Isotope mass | 238.049553 Da |
| Spin | 0 |
| Parent isotopes | 242Cm (α) 238Np (β−) 238Am (β+) |
| Decay products | 234U |
| Decay modes | |
| Decay mode | Decay energy (MeV) |
| Alpha decay | 5.593 |
| Isotopes of plutonium Complete table of nuclides | |
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 density of plutonium-238 at room temperature is about 19.8 g/cc. The material will generate about 0.57 watts per gram of 238Pu.
The bare sphere critical mass of metallic plutonium-238 is not precisely known, but its calculated range is between 9.04 and 10.07 kilograms.