81–90 of 141 posts
You too can achieve nuclear fusion! https://makezine.com/projects/nuclear-fusor/ And just like everyone else, you'll suck up a lot more energy than you'll produce
Any neutron generator that emits 14MeV neutrons is doing it with D-T fusion.
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Short story, they are shooting small plastic cubes with gas inside. The cubes are called "targets". The "bullet" is fast enough to compress the gas inside the cube, creating fusion. It works. But in the scenario it does work, a machine is manually opened, loaded, prepared, and then they do the shot. Whole process takes days to prepare. For it to be viable they need to do this every five seconds. That is a hard proble…
Ok. So dumb question. What complicates this beyond a conceptual belt fed heavy machine gun?
Conceptually, maybe nothing, but we aren't really talking about your average MG-42 here.
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>So either this key detail was kept secret for 50 years, or somehow history has been changed to confuse would-be bomb makers. I wonder how this detail came to light. Making a nuclear bomb has nothing to do with the knowledge of its' construction. Detailed plans are freely available to anyone who is interested. The reason you can't make a nuke is that the enrichment process of a suitable amount of fissile material req…
> The reason you can't make a nuke is that the enrichment process of a suitable amount of fissile material requires nation-state level of industrial output Is this still true in the 2020s?
The laws of physics haven't changed in 80 years. Even if you started with yellow cake uranium (~70% enriched, and itself already nearly impossible for a non-state actor to acquire), to reach weapons grade at >95% you'd need hundreds of tons of it, and massive industrial scale chemical facilities to convert that into uranium hexafluoride and pull out the U235 isotopes [0], where the ratio of U235 to U238 (the non-fissile isotope) is 99:1. The vast majority of the Manhattan Project was in the engineering challenges required to do this, not really in the construction of the bomb. So far, only 5 countries in the world have been able to do it.
[0] https://web.evs.anl.gov/uranium/guide/uf6/index.cfm#:~:text=....
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>So either this key detail was kept secret for 50 years, or somehow history has been changed to confuse would-be bomb makers. I wonder how this detail came to light. Making a nuclear bomb has nothing to do with the knowledge of its' construction. Detailed plans are freely available to anyone who is interested. The reason you can't make a nuke is that the enrichment process of a suitable amount of fissile material req…
> The reason you can't make a nuke is that the enrichment process of a suitable amount of fissile material requires nation-state level of industrial output Is this still true in the 2020s?
You still need thousands of kilograms of natural metallic uranium, which is a rare heavy metal with few commercial uses and one really salient illegal one, or thousands of tons of uranium ore, which, see previous. It's hard to buy this stuff secretly, because not many people have it, and people who do have it have a big, salient, vested interests in not selling it to people who want to make nukes! It's not like selling drones to Saudi Arabia and saying "oh well guess it'll suck to be a Houthi". You might get nuked!
Nation-states can pull this off, since they have both land and state security apparatuses. Empirically, private groups or terrorist cells haven't been able to do it. The rumors I've read and the impression I've received is that AQA spent decades trying, lost a lot of lieutenants and trucks full of cash to CIA honeypots, and eventually gave up. Too hard, too expensive, too many dead ends and entrapment schemes.
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I was going to say it fired a slug through a cylindrical piece of material, but decided to verify this on Wikipedia. It turns out: >> For the first fifty years after 1945, every published description and drawing of the Little Boy mechanism assumed that a small, solid projectile was fired into the center of a larger, stationary target.[31] However, critical mass considerations dictated that in Little Boy the larger, h…
>So either this key detail was kept secret for 50 years, or somehow history has been changed to confuse would-be bomb makers. I wonder how this detail came to light. Making a nuclear bomb has nothing to do with the knowledge of its' construction. Detailed plans are freely available to anyone who is interested. The reason you can't make a nuke is that the enrichment process of a suitable amount of fissile material req…
I would STRONGLY disagree that the Germans were ever more advanced than the Manhattan project. The British were a bit (~9 months) ahead of the US before S-1 started (December 1941), but I've never seen any evidence that the Germans were ahead of either country at any point. Certainly the fact that they never managed to replicate CP-1, which went critical in December 1942 (and was still years of hard work away from an actual nuclear bomb) suggests that they were never very close at all.
The closest I can come up with is that the discovery of nuclear fission in 1938. In that work, there were five people who collaborated closely enough that today they would have all had their names on the one paper (because of Nazis the work was published in two papers, Aryans on one, Jews on the other): Otto Hahn, Fritz Strassman, Lise Meitner, Otto Frisch, and Wilhelm Traube. Hahn and Strassman were considered Aryan enough to stay in Germany. Meitner and Frisch escaped- Frisch ended up working on the MAUD report and then at Los Alamos, Meitner stayed in neutral Sweden. Traube did not manage to escape and died in Gestapo custody in 1942. So 20% of this team ended up at Los Alamos, and only 40% managed to stay in Germany, which does somewhat point to some of the underlying problems any German bomb project would have had.
The amount of cynicism around fusion is stupid. It reminds me a lot of the learned helplessness that surrounded the idea of reusable spacecraft. A little engineering later: https://www.youtube.com/watch?v=sf4qRY3h_eo Fusion is a harder problem than that but we have no physical reason to believe it is not possible and the surrounding technology like compact higher temperature superconductors has advanced significantly…
For instance, the M1 has a density of 171 million/sq mm and claims 5 nm 2D equivalent, while Willow Cove from IBM looks much worse at 10nm but its density is 100.
Saying this not to "cast shade" on certain chip fabricators, just saying that it doesn't actually mean that they have taken the same style transistor fab processes from ~10 years ago and shrunk them down to 5nm. I mean, by the time an actual 2D feature would reach ~2nm, we'd be talking about features that were only about 10 atoms across.
As a nuclear fusion ignorant, where is the small print here? What's the catch, drawback, issue that it will make actually nonviable ?
Roughly speaking, the catch with every fusion-related "breakthrough" in the past 60+ years is the not-so-slight difference between: - "With a huge research budget, we found a nifty new way to reliably set a few tiny lumps of coal on fire in our lab." and - "We can reliably build useful and practical locomotives, ships, and electrical generating plants which are powered by burning coal... and are long-term economicall…
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'Scheme' in this case is a Britishism, basically meaning a project (not something nefarious).
Would Brits scheme , as a verb, in a non-nefarious way? I note we here use schema , which is partly why I interpret a scheme neutrally.
I don't know how the word carries so substantially different moral leanings, but that's English. I'm sure there are many other words with evil twins.
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> The reason you can't make a nuke is that the enrichment process of a suitable amount of fissile material requires nation-state level of industrial output Is this still true in the 2020s?
>Is this still true in the 2020s? The laws of physics haven't changed in 80 years. Even if you started with yellow cake uranium (~70% enriched, and itself already nearly impossible for a non-state actor to acquire), to reach weapons grade at >95% you'd need hundreds of tons of it, and massive industrial scale chemical facilities to convert that into uranium hexafluoride and pull out the U235 isotopes [0], where the r…
I think you’re a tad optimistic there - sadly we have many more than 5 nuclear powers today.
> First Light is working towards a pilot plant producing ~150 MW of electricity and costing less than $1 billion in the 2030s. Finally, fusion in only ten to twenty years. I've been waiting ten to twenty years for this!
This same joke has been made for twenty years. If we can't even make progress in fusion-related humor, maybe we really are doomed at fusion research.