Micro Nuclear Device: Is It Possible?

[Debree]

I have a limited understanding of how nuclear devices work and understand the basic physics related to fusion and fission.

However whilst I do not believe the latest assertions by Bashir the cleric from Indonesia who reckons the CIA set off a micro nuclear device in Bali - rather than it being some radical moslems from Indonesia.

It did get me to wondering though is there any such thing as a micro nuclear device? The explosions we classically see from nuclear tests and WW2 footage show enormous blasts, and the other information I have read seems to indicate that the critcal mass of product required would result in a sizable blast area - certainly much bigger than the one nightclub destroyed in Bali.

Can anyone tell me if:

a. there is any such thing as a micro nuclear bomb / device
b. if there was such a thing would it be possible for it to be mistaken for a normal device - ie by blast size?
c. and confirm that surely there would be some radiation output?

Thanks

 

[Bystander]

This'll get moved to S&D, or GD as a "conspiracy" thread. 'Bout the smallest nuclear warheads built for the U. S. arsenal were the Davy Crockett, or the "silver bullets" for the 155 (apocryphal --- heard about 'em at Ft. Sill, but never been able to confirm their existence). DC couldn't throw the warhead far enough to get the crew out of the fallout zone --- might as well put it in a suitcase and throw it --- after bending over, putting your head between your legs, and kissing your ass good-bye. 10-20 ton yield (not kton, ton) --- around half the size of the average mine under the Messines Ridge in WW I --- definitely more than enough to put the Bali club into low Earth orbit.

 

[Gelsamel Epsilon]

Critical mass of uranium in a sphere is approx. 20kgs I think, fusion doesn't need a specific mass or shape(obviously you want a lot for a large explosion), but it does need 100,000,000°c which is only obtainable by a normal nuclear explosion. So the smallest nuclear bomb would have to contain 20kgs of Uranium in 2 semi-spheres and some explosives as well as some neutron emmiters.

(I'm am in no way an expert on the matter but this is what I understand is required from my high-school knowledge and misc. facts I look up on the net)

 

[LURCH]

And yes; there would be radiation. In fact, it is likely that the ratio of radiation to blast size would be much worse for a smaller device, because the higher ratio of surface area to mass within the fissile material would render such a device much less efficient. I think there are other innefficiencyies associated with a smaller device, but this is just speculation on my part (so far).

What I do know for certain is that there is no known way to produce a fission reaction without releasing radiation.