3 ms·

> The fusion component also seems to involve some isotopes of hydrogen (tritium and deuterium), so it would be modestly helpful to have that but my understandin

> The fusion component also seems to involve some isotopes of hydrogen (tritium and deuterium), so it would be modestly helpful to have that but my understanding is that it's not that hard to get your hands on these isotopes. Tritium is the most expensive thing on the planet that any of us can buy, by weight. Only exotic matter (non-naturally occurring elements, anti-matter) is more expensive, and that you basically can't buy. Tritium is not easy to make or get. And it has a half-life of 12 years. Deuterium can't be used instead of tritium.

chasil 4y ago
...and you can buy a keychain with some of it. Don't break it. If you break it, don't breathe it. https://www.theregister.com/2015/03/18/atomic_keyring_brightness/ https://www.theregister.com/2015/03/18/atomic_keyring_bright...
- 762236 4y ago
  That's wild that people would engineer something so dangerous if broken, particularly if the people using it are unaware that it contains tritium.
  - NavinF 4y ago
    That's because it's not particularly dangerous unless you grind it up into powder and snort it. Tritium handgun sights are fairly common. Also see polonium from Amazon: https://www.youtube.com/watch?v=ZBHIp967TD8 https://www.youtube.com/watch?v=ZBHIp967TD8 Most discussions about radiation are pure FUD unless they come from someone that works with this stuff every day.
somat 4y ago
The rest of that "fun fact"(tm) usually goes There are a number of things more expensive than tritium, for example: I think plutonium is more expensive than tritium. but you can't buy plutonium.
- philipkglass 4y ago
  The post by cryptonector is correct: gram for gram, tritium for weapons is even more expensive to manufacture than plutonium for weapons. It takes one neutron to convert an atom of uranium 238 into an atom of plutonium 239. It also takes one neutron to convert an atom of lithium 6 into an atom of tritium and an atom of helium [1]. However, the plutonium 239 atom has a mass nearly 80 times as great as the tritium atom, so the manufacturing cost per gram is much higher. The US has always produced tritium for weapons by irradiation of lithium 6; the excess neutrons above and beyond that needed to support reactor criticality could be used to produce either tritium or plutonium. The competing uses for excess neutrons were a major issue early in the American development of thermonuclear weapons, when it looked like a thermonuclear weapon might need a lot of tritium (and therefore curtail the production of a lot more plutonium). Heavy water reactors like Canada's CANDU produce some tritium "for free" as a natural byproduct of neutron capture by deuterium. This gets removed [2] periodically from the heavy water moderator to reduce its radioactivity, and some of the surplus tritium gets sold. But by law Canadian tritium cannot be sold for weapons applications. [1] https://en.wikipedia.org/wiki/Tritium#Lithium https://en.wikipedia.org/wiki/Tritium#Lithium [2] https://www.opg.com/powering-ontario/our-generation/nuclear/darlington-nuclear/ https://www.opg.com/powering-ontario/our-generation/nuclear/...
  - cryptonector 4y ago
    Not that separating tritium from heavy water is cheap or anything... It's probably cheaper than making it the way the U.S. does it, though I wouldn't really know.

chasil 4y ago

...and you can buy a keychain with some of it. Don't break it. If you break it, don't breathe it. https://www.theregister.com/2015/03/18/atomic_keyring_brightness/ https://www.theregister.com/2015/03/18/atomic_keyring_bright...

762236 4y ago
That's wild that people would engineer something so dangerous if broken, particularly if the people using it are unaware that it contains tritium.
- NavinF 4y ago
  That's because it's not particularly dangerous unless you grind it up into powder and snort it. Tritium handgun sights are fairly common. Also see polonium from Amazon: https://www.youtube.com/watch?v=ZBHIp967TD8 https://www.youtube.com/watch?v=ZBHIp967TD8 Most discussions about radiation are pure FUD unless they come from someone that works with this stuff every day.

somat 4y ago

The rest of that "fun fact"(tm) usually goes There are a number of things more expensive than tritium, for example: I think plutonium is more expensive than tritium. but you can't buy plutonium.

philipkglass 4y ago
The post by cryptonector is correct: gram for gram, tritium for weapons is even more expensive to manufacture than plutonium for weapons. It takes one neutron to convert an atom of uranium 238 into an atom of plutonium 239. It also takes one neutron to convert an atom of lithium 6 into an atom of tritium and an atom of helium [1]. However, the plutonium 239 atom has a mass nearly 80 times as great as the tritium atom, so the manufacturing cost per gram is much higher. The US has always produced tritium for weapons by irradiation of lithium 6; the excess neutrons above and beyond that needed to support reactor criticality could be used to produce either tritium or plutonium. The competing uses for excess neutrons were a major issue early in the American development of thermonuclear weapons, when it looked like a thermonuclear weapon might need a lot of tritium (and therefore curtail the production of a lot more plutonium). Heavy water reactors like Canada's CANDU produce some tritium "for free" as a natural byproduct of neutron capture by deuterium. This gets removed [2] periodically from the heavy water moderator to reduce its radioactivity, and some of the surplus tritium gets sold. But by law Canadian tritium cannot be sold for weapons applications. [1] https://en.wikipedia.org/wiki/Tritium#Lithium https://en.wikipedia.org/wiki/Tritium#Lithium [2] https://www.opg.com/powering-ontario/our-generation/nuclear/darlington-nuclear/ https://www.opg.com/powering-ontario/our-generation/nuclear/...
- cryptonector 4y ago
  Not that separating tritium from heavy water is cheap or anything... It's probably cheaper than making it the way the U.S. does it, though I wouldn't really know.