Questions about Micro-Nukes

[lenbrazil]

A while ago the issue of "nicro nukes" came up on the 9-11 thread. But some question remained unanswered.

What evidence is there (if any) that such weapons exist?

Wouldn't these bombs be expected to leave the same tell tail signs as the "big brothers" ?

Such as: blinding flashes

mushroom clouds and

radioactivity

[Al Johnston]

There's not even much evidence that they can exist.

In principle any amount of plutonium can be a critical mass if it is sufficiently compressed.

Similarly, there is no lower bound on the amount of fusion fuel that will fuse if it's heated enough.

The key phrases of course being "sufficiently compressed" and "heated enough".

There's a lot of hand-waving goes on about lasers, but the idea that such devices would be practicable, much less man-portable is far-fetched to say the least.

[Retrograde]

alasdhair said:

Similarly, there is no lower bound on the amount of fusion fuel that will fuse if it's heated enough.

Well, you need at least two atoms (ducks) ;D

[grashtel]

alasdhair said:

There's not even much evidence that they can exist.

In principle any amount of plutonium can be a critical mass if it is sufficiently compressed.

Similarly, there is no lower bound on the amount of fusion fuel that will fuse if it's heated enough.

The key phrases of course being "sufficiently compressed" and "heated enough".

There's a lot of hand-waving goes on about lasers, but the idea that such devices would be practicable, much less man-portable is far-fetched to say the least.

The W54 warhead's existance is quite well documented and at just over 50 pounds was definitely man portable with a yeild of between 10 tons and 1 kiloton. Though it was a conventional fission bomb rather than fusion and produced a lot of residual radiation due to an inefficent reaction. SOme referances for it are en.wikipedia.org/wiki/W54 www.brook.edu/FP/projects/nucwcost/davyc.HTM nuclearweaponarchive.org/Nwfaq/Nfaq4-2.html (section 4.2.3)

[Al Johnston]

Ah well, live and learn: but surely the most expensive tiny bangs for such a big pile of bucks ;D

[Count Zero]

The thing about mini-nukes is that the radiation effects are very obvious.

The three primary effects of atmospheric nuclear explosions are blast, thermal (flash) and radiation. All of these are to one extent or another affected by attenuation due to distance and absorption in the atmosphere.

-Blast attenuates as the inverse cube of the distance.

-Thermal attenuates as the inverse square of the distance. Larger yields cause longer flashes, which causes greater thermal damage.

-Initial radiation (I'm mainly talking gamma, here) attenuates as the square of the distance but it is strongly affected by atmospheric absorption.

High-yield (i.e. multimegaton) weapons are mainly incendiary devices that can cause 3rd degree burns well outside the range of 3 psi overpressure that would cause structural damage to a house.

Mid-kiloton range weapons cause significant blast & thermal damage at roughly similar ranges. For this size & greater, anyone close enough to pick up a significant dose of initial radiation would almost certainly be killed by burns or blast.

The bombs dropped on Japan were medium-low kiloton weapons. Some people who were shielded from the flash & blast later succumbed to radiation sickness. At first the Americans didn't believe this, since they (correctly) figured that most casualties would be from the predominant effects. They overlooked the math that says a few percent of a population of 100,000+ is still several thousand victims (we also found out, much later, that the gun-type device dropped on Hiroshima generated a much higher neutron flux than previously thought).

At the low-kiloton range, the flash gets very short, and blast effects would seem to dominate, but as you get into the sub-kiloton range, the range of a "radiation kill" exceeds all but the most superficial blast damage. The afore-mentioned W-54 warhead was tested as part of Operation Sun Beam at ~.02 kilotons (20 tons). At 0.3 miles from the ground zero, an exposed person would not have received even a first degree burn. Though they might be knocked to the ground (1-2 psi overpressure), they would avoid blast injury unless they were standing in front of a glass window. However, they would get a 500+ REM dose of radiation, which would definitely make them sick, and have a 50% chance of killing them in the next month or two.

A mini-nuke in lower Manhattan would have caused mass radiation casualties that would have been as obvious as they would be horrific.

[twinstead]

Sheesh, Count Zero, you obviously forgot to take into account reverse-engineered alien non-radiation emitting micro-nuke technology developed in Area 51.

[Count Zero]

Heh-heh-heh!

[OT] A couple of months ago I was watching the SF classic The Thing From Another World. When they find the flying saucer buried in the ice, they pick up its atomic power plant on their Geiger counter. After the ship explodes, they don't detect any radioactivity any more. ;D [/OT]

[jaydeehess]

countzero said:

Heh-heh-heh!

[OT] A couple of months ago I was watching the SF classic The Thing From Another World. When they find the flying saucer buried in the ice, they pick up its atomic power plant on their Geiger counter. After the ship explodes, they don't detect any radioactivity any more. ;D [/OT]

Well of course not silly. It all burned up when the ship exploded. Sheesh