What it takes to make a nuclear weapon

a reply to: AugustusMasonicus

I go past a mine every so often that has the biggest crane I've ever seen digging in it. I could park my truck and trailer next to it and they'd look like toys.

originally posted by: Xeven

Wonder how high powered magnetic waves, xrays other high energy directed at the uranium would effect the reactions. Did the test any of that back in the day?

X-ray bombardment of the polystyrene foam by the fission primary is what is used to compress the fusion secondary in a thermonuclear device.

originally posted by: Zaphod58
I go past a mine every so often that has the biggest crane I've ever seen digging in it. I could park my truck and trailer next to it and they'd look like toys.

Did you ever stop, wander around and scoop up a few hundred pounds of stray uranium ore?

originally posted by: stgeorge
the kid who built the MOCK UP nuclear device was not a genious by any means. Physics i think it was.Where do you get off that you need rocket scientists to design the things and Stratofortresses to carry them?

If you can put a nuclear warhead in an American 155 shell or a russian 130mm,how complicated do you think it is? None of these complicated shaped charges to create critical mass.

That warhead doesn't have a big yield. But it is one of the easier designs. It also violates the DOE design rules which is why it wasn't fielded long. The design's got an emission and fratricide issue, and it's heinously inefficient.

In theory ,put a lump of Uranium on an anvil and hit it very hard with a sledgehammer and it will go off.

Not at all. In fact, if it was subcritical as a "lump" (let's posit that lump was spherical) if you hit it very hard with a sledgehammer, it's likely not much would happen at all, as Uranium's really dense and not that malleable. But let's say you were Thor and were whacking away with Mjollnir, you'd be flattening a sphere. A normal cylindrical section is of lower criticality than a sphere of the same mass. So pancaking it would make it farther from critical, not closer.

In this case,the warhead has a berillium "anvil,and a "gun" shoots the Uranium into it.
And BTW,nice of you to keep insinuating Iran is your next unholy target.You just re-energized their nuke program.

Not at all. However, you could mix some beryllium in with the other bits and enhance the efficiency if you knew what you were doing.

originally posted by: AugustusMasonicus
I suspect you do not really have any idea how uranium ore is mined, separated from the surrounding strata, along with the huge amount of machines and ancillary apparatus required to complete this process.

It's rather more involved than a lone citizen could do.

So you'd have to do something else.

There are a few possibilities. Someone once made some suggestions that were actually not bad, if you took that and ran with it. *coffTedTaylorcoff*

If you had plutonium and you either didn't get enough, or you weren't real sure of your ability to pull it off technically, you can do something that's a lot more primitive, yet, given just the right conditions, would really * up a lot of people and ruin a chunk of expensive real estate.

originally posted by: Xeven
Wonder how high powered magnetic waves, xrays other high energy directed at the uranium would effect the reactions. Did the test any of that back in the day?

No need to. Magnetism doesn't affect the nucleus much, at least not in the way of making it any more or less stable.

EM won't affect the nucleus a lot either, until you get into that fabled world where the wavelength of the EM you're using is starting to compare to the diameter of the nucleus, and that's very hard gammas indeed. If you could do that, though, you don't need the nuclear reaction, you've got a dandy death ray.

originally posted by: AugustusMasonicus
X-ray bombardment of the polystyrene foam by the fission primary is what is used to compress the fusion secondary in a thermonuclear device.

That doesn't affect the uranium or plutonium, though.

The stuff is made by Alliant Techsystems. At one point, it was a stock item, but I was never sure if it was a honeypot.

a reply to: Bedlam

Interesting. That is the first I have heard that the foam plasma pressure aspect of the Teller-Ulam design was possibly a decoy system.

originally posted by: AugustusMasonicus
a reply to: Bedlam

Interesting. That is the first I have heard that the foam plasma pressure aspect of the Teller-Ulam design was possibly decoy system.

Oh. Well, there's two components to the answer here.

One, the original question was, do magnetic fields, EM etc do something to the material in such a way that you might use a "trigger ray" and set off the chain reaction. At least that's the way I interpreted it. As such, turning some high density poly into plasma with x-rays doesn't really fulfill that description.

and

Two, well, (hem haw) it's a small part of what's going on. But the bulk of the compression comes from radiative ablation of the outside of the cylinder.

a reply to: Bedlam

Gotcha. The fission primary is used to compress the secondary via ablation of the heavy metal casing (tamper-pusher).

a reply to: AugustusMasonicus

I'm too afraid that thing would squish me and not even leave a smear to try.

a reply to: AugustusMasonicus

That's right. The various tricks are there to modulate the frequency and time-dependence of the x-ray pulse in order to get the maximum mechanical work done on the compressor.

Like tuning an internal combustion engine. You need to have the explosion timed correctly and have the right profile to transfer most work to the piston instead of causing just plain entropy.

This modeling is the main reason why full fusion weapons are much more scientifically complicated than fission-only weapons.

And there are unknowns which have to be determined experimentally.

As far as the foam, after all you probably want to physically secure the various parts anyway and don't want them to rattle around especially if you're launching and vibrating them at some crazy g-force. You're going to need some packing foam anyway, and it will participate physically anyway, so optimize its properties.

a reply to: mbkennel
I believe that the foam used in a nuclear device, is UHMW foam (ultra high molecular weight polyethyene, ie milk bottle plastic) and is used as a neutron source.