3 ms·

Why the heck are we welding plutonium ?

by euroderf 3y ago

mike256 3y ago
Because some people think the world needs nuclear weapons :-(
- thsksbd 3y ago
  We conceded that part. The question is: What about nuclear weapons needs welding?
  - PaulHoule 3y ago
    According to https://discover.lanl.gov/publications/national-security-science/2021-winter/pit-production-explained/ https://discover.lanl.gov/publications/national-security-sci... Pieces of cast plutonium are then welded together to form a pit Note if the world (ex. Russia) ever gets interested in the fast breeder reactor, or even if we try to get the absolute most out of the LWR https://www.neimagazine.com/features/featurean-advanced-fuel-for-lwr-and-smr-designs-11283875/ https://www.neimagazine.com/features/featurean-advanced-fuel... there may be revived interest in casting fuel elements out of mixed U, Pu and Zr like so https://www.youtube.com/watch?v=KEfhx5ovuYk https://www.youtube.com/watch?v=KEfhx5ovuYk a technology which has been quietly used in marine nuclear reactors for years. This competes with the oxide fuels ordinarily used in civil LWRs and that the French have developed to make mixed-oxide (part U, part Pu) fuels. Problem with that is that quality MOX fuel is made of U and Pu alloyed in a high-energy ball mill but that makes nano particles that are highly effective at getting in your lungs and causing cancer. That is a problem with casting too, but making MOX fuel means you need to pick up fuel pellets with gloves and carefully stuff them in a tube whereas you don’t have to get anywhere near a cast fuel rod.
  - deleted 3y ago
    [deleted]
danbruc 3y ago
Was wondering the same, I would not have expected welds in places where plutonium is used and assumed things like casting, forging, and machining is what you do to plutonium. Maybe this was just for research, just in case the need ever arises? Or for experimental setups?
- chainingsolid 3y ago
  Addative manufactering (welding) has the advantage of working towards a critical mass. Where as subtractive requires getting even closer to it then moving away from it, as you make the desired part.
  - danbruc 3y ago
    Interesting point but would that really be relevant? If you have a hollow pit or one with an initiator in the center, you will be making two half-spheres, so you will be far away from the critical mass. And even if you are making a solid pit, I would have assumed that you are quite a bit away from the critical mass without neutron reflectors and the compression from the detonation.
    - icegreentea2 3y ago
      I think you'd want to weld the two half spheres together to give a more consistent mechanical fit to help with your implosion efficiency.

Why the heck are we welding plutonium ?

mike256 3y ago

Because some people think the world needs nuclear weapons :-(

thsksbd 3y ago
We conceded that part. The question is: What about nuclear weapons needs welding?
- PaulHoule 3y ago
  According to https://discover.lanl.gov/publications/national-security-science/2021-winter/pit-production-explained/ https://discover.lanl.gov/publications/national-security-sci... Pieces of cast plutonium are then welded together to form a pit Note if the world (ex. Russia) ever gets interested in the fast breeder reactor, or even if we try to get the absolute most out of the LWR https://www.neimagazine.com/features/featurean-advanced-fuel-for-lwr-and-smr-designs-11283875/ https://www.neimagazine.com/features/featurean-advanced-fuel... there may be revived interest in casting fuel elements out of mixed U, Pu and Zr like so https://www.youtube.com/watch?v=KEfhx5ovuYk https://www.youtube.com/watch?v=KEfhx5ovuYk a technology which has been quietly used in marine nuclear reactors for years. This competes with the oxide fuels ordinarily used in civil LWRs and that the French have developed to make mixed-oxide (part U, part Pu) fuels. Problem with that is that quality MOX fuel is made of U and Pu alloyed in a high-energy ball mill but that makes nano particles that are highly effective at getting in your lungs and causing cancer. That is a problem with casting too, but making MOX fuel means you need to pick up fuel pellets with gloves and carefully stuff them in a tube whereas you don’t have to get anywhere near a cast fuel rod.
- deleted 3y ago
  [deleted]

danbruc 3y ago

Was wondering the same, I would not have expected welds in places where plutonium is used and assumed things like casting, forging, and machining is what you do to plutonium. Maybe this was just for research, just in case the need ever arises? Or for experimental setups?

chainingsolid 3y ago
Addative manufactering (welding) has the advantage of working towards a critical mass. Where as subtractive requires getting even closer to it then moving away from it, as you make the desired part.
- danbruc 3y ago
  Interesting point but would that really be relevant? If you have a hollow pit or one with an initiator in the center, you will be making two half-spheres, so you will be far away from the critical mass. And even if you are making a solid pit, I would have assumed that you are quite a bit away from the critical mass without neutron reflectors and the compression from the detonation.
  - icegreentea2 3y ago
    I think you'd want to weld the two half spheres together to give a more consistent mechanical fit to help with your implosion efficiency.