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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.
238 Pu has become the most widely used fuel for RTGs, in the form of plutonium(IV) oxide (PuO 2). [37] 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.
Download as PDF; Printable version; ... This is an extended version of the energy density table from the main Energy density page: ... Pu-238 α-decay: 2,200,000:
Plutonium dioxide is a stable ceramic material with an extremely low solubility in water and with a high melting point (2,744 °C). The melting point was revised upwards in 2011 by several hundred degrees, based on evidence from rapid laser melting studies which avoid contamination by any container material.
It would have produced 140 watts of electricity using a quarter of the plutonium an RTG or MMRTG needs. [11] The two finished units had these expected specifications: [12] ≥14-year lifetime; Nominal power: 130 W; Mass: 32 kg (71 lb) System efficiency: ≈ 26%; Total mass of plutonium-238-dioxide: 1.2 kg (2.6 lb)
Decay heat as fraction of full power for a reactor SCRAMed from full power at time 0, using two different correlations. In a typical nuclear fission reaction, 187 MeV of energy are released instantaneously in the form of kinetic energy from the fission products, kinetic energy from the fission neutrons, instantaneous gamma rays, or gamma rays from the capture of neutrons. [7]
Plutonium-238 must be deliberately produced via neutron irradiation of Neptunium-237 but it can be easily converted into a stable plutonium oxide ceramic. Strontium-90 is easily extracted from spent nuclear fuel but must be converted into the perovskite form strontium titanate to reduce its chemical mobility, cutting power density in half ...
To reduce the concentration of Pu-240 in the plutonium produced, weapons program plutonium production reactors (e.g. B Reactor) irradiate the uranium for a far shorter time than is normal for a nuclear power reactor. More precisely, weapons-grade plutonium is obtained from uranium irradiated to a low burnup.