Here the Difference:
Atomic Weapons - Atomic Fission created after conventional trigger heats atoms to required temperature and then splits them. Two explosions occur.
Nuclear Weapons - Nuclear Fission is achieved when when a small conventional explosion accelerates a neutron and it bombards an atom of say,
uranium-238. The Uranium is broken into two other elements such as Barium and Krypton while at least three more neutrons are ejected from the original
uranium atom and impact into more atoms of uranium. Again, two explosions occur.
You're confusing the difference of Atomic weapons and Nuclear weapons with the difference of traditional Nuclear weapons and Thermonuclear
Atomic and Nuclear weapons are the exact same, so there's no point trying to compare and contrast them. What you were really trying to do up there
was to differentiate between Nuclear and Thermonuclear... and you actually ended up repeating the same description for both of them.
Our ordinary nuclear weapon:
Two (or more) pieces of Fissile material, say Uranium-235 are in the bomb, not touching eachother (probably insulated too). The weight of these pieces
combined should add up to the critical mass of the fissile fuel in question, in this case U-235, which is about 50 Kg.
Now, to trigger it, we either use a small explosive to break the insulation between the two, or we use an explosive at one end of a tube to ram one
of the pieces to the rest of the pieces, achieving critical mass, and thus setting off massive nuclear decay almost instantly. The result is a instant
release of energy so destructive that it blows apart the fissile material before it has a chance to reach anywhere near it's maximum potential (the
Nagasaki bomb, at 20 Kt, achieved about 1% efficiency, that is to say that only 1% of the Pu-239 decayed before the structure of the pu-239 ball was
blown away completely by it's own blast).
A Thermonuclear bomb:
We use our normal nuclear fission bomb, but we add 2 things: Deutrium Hydrogen and Tritium* Hydrogen somewhere near the fission bomb (and sometimes
inside of it). When the fission bomb goes off, the extreme amount of energy released has made it hot enough for a fusion reaction to take place
between the Deutrium and Tritium. This has a dual effect: Not only does this new fusion reaction produce an immense amount of energy by itself, it
also lets the fission bomb to feed off more neutrons that are coming it's way from the fusion part, and thus allowing it to decay faster than it
Thermonuclear bombs can be many, many times more powerful than regular nuclear weapons. The most powerful one ever constructed and set off was a 50
megaton bomb called the tsar bomba in the Soviet Union.
*Tritium is highly unstable, so they actually use a different compound which decays at the high heat of fission, leaving Tritium as a by-product, but
for the purpose of this post lets just assume it's regular Tritium they put in there.
P.S. Contrary to your post, U-238 CANNOT be used as fissile fuel.
[edit on 10-9-2004 by naked_turk]