 Plutonium-238 oxide pellet glowing from its decay heat | |
| General | |
|---|---|
| Symbol | 238Pu |
| Names | plutonium-238, 238Pu, Pu-238 |
| Protons (Z) | 94 |
| Neutrons (N) | 144 |
| Nuclide data | |
| Half-life (t1/2) | 87.7 years[1][2] |
| 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.[3] The material will generate about 0.57 watts per gram of 238Pu.[4]
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.[5]
- ^ Rebuilding the supply of Pu-238. Oregon State University.
- ^ US restarts production of plutonium-238 to power space missions. David Szondy, New Atlas. 23 December 2015.
- ^ Calculated from the atomic weight and the atomic volume. The unit cell, containing 16 atoms, has a volume of 319.96 cubic Å, according to Siegfried S. Hecker (2000). "Plutonium and its alloys: from atoms to microstructure" (PDF). Los Alamos Science. 26: 331.. This gives a density for 238Pu of (1.66053906660×10−24g/dalton×238.0495599 daltons/atom×16 atoms/unit cell)/(319.96 Å3/unit cell × 10−24cc/Å3) or 19.8 g/cc.
- ^ Miotla, Dennis (April 21, 2008). "Assessment of Plutonium-238 production alternatives" (PDF). www.energy.gov. p. 3. Retrieved September 21, 2020.
- ^ A. Blanchard; et al. (1999). Updated Critical Mass Estimates for Plutonium-238 (WSRC-MS-99-00313) (Report). Savannah River Site.