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How would it help build better weapons? I thought the existing thermonuclear bombs do the job perfectly fine. Sure, the military might want to make them a bit s

by _cs2017_ 4y ago

How would it help build better weapons? I thought the existing thermonuclear bombs do the job perfectly fine. Sure, the military might want to make them a bit smaller or a bit cheaper, but is it really such a big deal as to warrant a major announcement?

jacquesm 4y ago
Given the limitations on nuclear research for weapons purposes any information that can be gleaned from these experiments that is 'dual use' is more than welcome with the parties that are currently stymied by various arms control agreements. This is also why you will see a lot of supercomputer capacity near such research, it allows simulation of experiments with high fidelity rather than the experiments themselves. These are all exploitation of loopholes. The biggest value is probably in being able to confirm that the various computer models accurately predict the experimental outcomes. This when confirmed at scale will allow for the computer models to be used for different applications (ie: weapons research) with a higher level of confidence.
- _cs2017_ 4y ago
  Presumably these computer models are mostly useful for creating new designs (since the old designs were proven by real tests). Would such new designs be convincing enough to the adversary to fulfill its role as a strategic deterrence? When (in XX years?) almost all US nukes are only simulated on computers and not actually tested, the Russians may start wondering if the US aresnal actually works, no? That would be a horrible outcome, since it means the Russians would be taking somewhat greater risks in their decision-making. Wouldn't far outweigh any opertaional or financial benefits the newer designs offer? I suppose one could argue that if the loss of confidence in strategic weapons matched the actual loss in reliability, it might be a "no op" (although even this is arguable). But if the Russians think the US simulations suck, while the US is actually building really good simulations, the loss of confidence would be greater than the actual loss in reliability. In the extreme case, the nukes work great, but everyone thinks they are scrap metal. Of course, the same happens in reverse: if the Russians are upgrading their weapons to untested designs, the US may start underestimating the risk.
  - jacquesm 4y ago
    > the Russians may start wondering if the US aresnal actually works, no? If anything the last year or so has probably made the reverse happening and the US and its adversaries likely both have very high confidence in that the US arsenal actually works.
  - jboy55 4y ago
    Or the US finds that after x many years bombs degrade in unexpected ways, and that while we were able to figure this out and fix it. Then we speculate that the Russians probably haven't fixed theirs in the same way and their bombs aren't good anymore. Which means the risk of a nuclear war just jumps up, since MAD is compromised.
prpl 4y ago
experimental verification of models with actual materials used in existing bombs, for one.
bunabhucan 4y ago
"Nuclear stockpile research" is only making weapons "better" in the sense that they are reliable despite not having been tested in decades. There's probably a component of "unemployed nuclear weapons designers is a bad thing" also. The fusion for power experiments are using the same laser equipment but different targets and sensors.
- jboy55 4y ago
  I wonder if they achieved a high Q value decades ago, but using the targets more inline with the bomb materials.
- njarboe 4y ago
  The DOD also probably likes having some nuclear weapons designers available on short notice
User23 4y ago
The USA no longer has the technical capability to manufacture the necessary parts to maintain the current stockpile. The whole strategic arms reduction treaty regime is basically a fig leaf to cover for the fact that we have to cannibalize some legacy weapons to maintain the rest. If nothing changes the USA probably won't have an effective arsenal within a century. Given the likely state of the USA by that time, that's probably for the best.
- pauljurczak 4y ago
  > USA probably won't have an effective arsenal within a century. If other countries joined, it would be a great outcome.
  - kubanczyk 4y ago
    > > USA probably won't have an effective arsenal within a century. > If other countries joined, it would be a great outcome. Why the optimism? Without MAD, it's nearly certain that we'd have a world war at some point in time. Sooner or later, it will surely happen. If you think it won't happen, or won't cost millions of lives, or won't employ re-developed nukes eventually, please tell me why you think so. (No sarcasm.)
    - scoopertrooper 4y ago
      I don’t think MAD is all that effective. At this moment in time we’re seeing: * Several concurrent arms races in the Middle East, Asia, and Europe * A high intensity conflict in Ukraine * China threatening a land invasion into Taiwan MAD might be preventing a country like Poland from jumping into the Ukraine conflict, but more likely it’s because of its involvement in NATO. I think collective security organisations are a far more potent force for peace than nuclear weapons. If countries abided by their security agreements in WW2, then we’d have nipped the entire thing in the bud.
      - lucumo 4y ago
        > I don’t think MAD is all that effective. At this moment in time we’re seeing: > * Several concurrent arms races in the Middle East, Asia, and Europe > * A high intensity conflict in Ukraine > * China threatening a land invasion into Taiwan I mean... Only one of those is an actual fight. And there MAD doesn't apply because the defender doesn't have the Assured Destruction capability needed.
atemerev 4y ago
To learn about their degradation modes and how to maintain them (since full-scale nuclear tests are now verboten, and subcritical experiments only deal with fission part of the entire assembly -- we now also need some experimental setup to test the fusion part: radiation pressure, X-ray reflection, ablation modes etc. NIF is this setup). Also, there is a constant need to improve fusion/fission rate in the total energy output, and perhaps eventually design pure fusion weapons, though this is still probably out of reach.
speeder 4y ago
I guess they also don't want to blow up random civilians by accident again. When castle bravo was tested, we didn't knew that lithium7 fusion was possible and that it would generate energy. The bomb had a lot of lithium7 because it was cheaper than lithium6. Castle Bravo then proceeded to explode with way more power than intended, it vaporized the measurement instruments, ruined the test site, damaged civilian property and caused a horrible amount of fallout that screwed a enormous amount of people from more than one country. Even during war, I suppose you want your explosions to behave in the way you expect... so you need to figure out all the physics related to them.
- metadat 4y ago
  More on Castle Bravo: https://en.wikipedia.org/wiki/Castle_Bravo https://en.wikipedia.org/wiki/Castle_Bravo

jacquesm 4y ago

Given the limitations on nuclear research for weapons purposes any information that can be gleaned from these experiments that is 'dual use' is more than welcome with the parties that are currently stymied by various arms control agreements. This is also why you will see a lot of supercomputer capacity near such research, it allows simulation of experiments with high fidelity rather than the experiments themselves. These are all exploitation of loopholes. The biggest value is probably in being able to confirm that the various computer models accurately predict the experimental outcomes. This when confirmed at scale will allow for the computer models to be used for different applications (ie: weapons research) with a higher level of confidence.

_cs2017_ 4y ago
Presumably these computer models are mostly useful for creating new designs (since the old designs were proven by real tests). Would such new designs be convincing enough to the adversary to fulfill its role as a strategic deterrence? When (in XX years?) almost all US nukes are only simulated on computers and not actually tested, the Russians may start wondering if the US aresnal actually works, no? That would be a horrible outcome, since it means the Russians would be taking somewhat greater risks in their decision-making. Wouldn't far outweigh any opertaional or financial benefits the newer designs offer? I suppose one could argue that if the loss of confidence in strategic weapons matched the actual loss in reliability, it might be a "no op" (although even this is arguable). But if the Russians think the US simulations suck, while the US is actually building really good simulations, the loss of confidence would be greater than the actual loss in reliability. In the extreme case, the nukes work great, but everyone thinks they are scrap metal. Of course, the same happens in reverse: if the Russians are upgrading their weapons to untested designs, the US may start underestimating the risk.
- jacquesm 4y ago
  > the Russians may start wondering if the US aresnal actually works, no? If anything the last year or so has probably made the reverse happening and the US and its adversaries likely both have very high confidence in that the US arsenal actually works.
- jboy55 4y ago
  Or the US finds that after x many years bombs degrade in unexpected ways, and that while we were able to figure this out and fix it. Then we speculate that the Russians probably haven't fixed theirs in the same way and their bombs aren't good anymore. Which means the risk of a nuclear war just jumps up, since MAD is compromised.

prpl 4y ago

experimental verification of models with actual materials used in existing bombs, for one.

bunabhucan 4y ago

"Nuclear stockpile research" is only making weapons "better" in the sense that they are reliable despite not having been tested in decades. There's probably a component of "unemployed nuclear weapons designers is a bad thing" also. The fusion for power experiments are using the same laser equipment but different targets and sensors.

jboy55 4y ago
I wonder if they achieved a high Q value decades ago, but using the targets more inline with the bomb materials.
njarboe 4y ago
The DOD also probably likes having some nuclear weapons designers available on short notice

User23 4y ago

The USA no longer has the technical capability to manufacture the necessary parts to maintain the current stockpile. The whole strategic arms reduction treaty regime is basically a fig leaf to cover for the fact that we have to cannibalize some legacy weapons to maintain the rest. If nothing changes the USA probably won't have an effective arsenal within a century. Given the likely state of the USA by that time, that's probably for the best.

pauljurczak 4y ago
> USA probably won't have an effective arsenal within a century. If other countries joined, it would be a great outcome.
- kubanczyk 4y ago
  > > USA probably won't have an effective arsenal within a century. > If other countries joined, it would be a great outcome. Why the optimism? Without MAD, it's nearly certain that we'd have a world war at some point in time. Sooner or later, it will surely happen. If you think it won't happen, or won't cost millions of lives, or won't employ re-developed nukes eventually, please tell me why you think so. (No sarcasm.)
  - scoopertrooper 4y ago
    I don’t think MAD is all that effective. At this moment in time we’re seeing: * Several concurrent arms races in the Middle East, Asia, and Europe * A high intensity conflict in Ukraine * China threatening a land invasion into Taiwan MAD might be preventing a country like Poland from jumping into the Ukraine conflict, but more likely it’s because of its involvement in NATO. I think collective security organisations are a far more potent force for peace than nuclear weapons. If countries abided by their security agreements in WW2, then we’d have nipped the entire thing in the bud.
    - lucumo 4y ago
      > I don’t think MAD is all that effective. At this moment in time we’re seeing: > * Several concurrent arms races in the Middle East, Asia, and Europe > * A high intensity conflict in Ukraine > * China threatening a land invasion into Taiwan I mean... Only one of those is an actual fight. And there MAD doesn't apply because the defender doesn't have the Assured Destruction capability needed.

atemerev 4y ago

To learn about their degradation modes and how to maintain them (since full-scale nuclear tests are now verboten, and subcritical experiments only deal with fission part of the entire assembly -- we now also need some experimental setup to test the fusion part: radiation pressure, X-ray reflection, ablation modes etc. NIF is this setup). Also, there is a constant need to improve fusion/fission rate in the total energy output, and perhaps eventually design pure fusion weapons, though this is still probably out of reach.

speeder 4y ago

I guess they also don't want to blow up random civilians by accident again. When castle bravo was tested, we didn't knew that lithium7 fusion was possible and that it would generate energy. The bomb had a lot of lithium7 because it was cheaper than lithium6. Castle Bravo then proceeded to explode with way more power than intended, it vaporized the measurement instruments, ruined the test site, damaged civilian property and caused a horrible amount of fallout that screwed a enormous amount of people from more than one country. Even during war, I suppose you want your explosions to behave in the way you expect... so you need to figure out all the physics related to them.

metadat 4y ago
More on Castle Bravo: https://en.wikipedia.org/wiki/Castle_Bravo https://en.wikipedia.org/wiki/Castle_Bravo