Alexander Litvinenko Created 2024-08-14 Updated 2025-07-16
Russian dissident Created 2024-08-14 Updated 2025-07-16
Alpha particles have low penetration depth Created 2024-08-14 Updated 2025-07-16
They are stopped by:
  • by a few centimeters of air
  • a sheet of paper
  • the skin
Therefore, alpha emitters are not too dangerous unless ingested.
Gun-type fission weapons don't work with plutonium Created 2024-08-14 Updated 2025-07-16
Gun-type fission weapons don't work with Plutonium-239 because of the presence of Plutonium-240 as an impurity which leads to fizzle.
Gamma spectroscopy Created 2024-08-14 Updated 2025-07-16
Figure 1.
Gamma spectroscopy of a Uranium ore
. Source. Several points of the Uranium 238 decay chain are clearly visible.
Breeder reactor Created 2024-08-14 Updated 2025-07-16
A nuclear reactor made to produce specific isotopes rather than just consume fissile material to produce electrical power. The most notably application being to produce Plutonium-239 for nuclear weapons from Uranium-238 being irradiated from Uranium-235-created fission.
Weapon grade Plutonium is cheaper than weapon grade Uranium Created 2024-08-14 Updated 2025-07-16
Because you can generate plutonium-239 from uranium-238 in a breeder reactor, and then separate the plutonium-239 from the Uranium simply by using chemistry methods because you've created an element with different valence electrons.
Isn't it somewhat funny that it is easier to purify a synthetic element than a naturally occurring one?
Thorium-232 Created 2024-08-14 Updated 2025-07-16
GPHS-RTG Created 2024-08-14 Updated 2025-07-16
Figure 1.
GPHS-RTG diagram
. Source.
Figure 2.
Cassini probe's RTG before installation
. Source.
Polonium-209 Created 2024-08-14 Updated 2025-07-16
Polonium-208 Created 2024-08-14 Updated 2025-07-16
Plutonium-240 Created 2024-08-14 Updated 2025-07-16
This isotope shows up as an inevitable contaminant in Plutonium-239 for nuclear weapons, because it emits neutrons too fast and makes it harder to assemble the critical mass without fizzle.
Wikipedia explains that Pu-240 is formed by Pu-239 Neutron capture:
About 62% to 73% of the time when 239Pu captures a neutron, it undergoes fission; the remainder of the time, it forms 240Pu.
so its presence is inevitable.
Plutonium-239 Created 2024-08-14 Updated 2025-07-16
This is the isotope that is produced for nuclear weapons by irradiating Uranium-238 with a neutron.
Plutonium-240 is a contaminant.
Plutonium-238 Created 2024-08-14 Updated 2025-07-16
Strong alpha emitter. Can be used as an atomic battery.
Figure 1.
Plutonium-238-oxide pellet glowing under its own heat
. Source. Unlike for nuclear applications, we don't need the pure metal, so the oxide 238PuO2 is used instead as it is more chemically stable.
S-50 liquid thermal diffusion plant Created 2024-08-14 Updated 2025-07-16

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