Originally posted by russiankid
question: what is plutonium????
Uranium & Plutonium
Uranium-235 is very difficult to extract. In fact, for every 25,000 tons of Uranium ore that is mined from the earth, only 50 tons of Uranium metal
can be refined from that, and 99.3% of that metal is U-238 which is too stable to be used as an active agent in an atomic detonation. To make matters
even more complicated, no ordinary chemical extraction can separate the two isotopes since both U-235 and U-238 possess precisely identical chemical
characteristics. The only methods that can effectively separate U-235 from U-238 are mechanical methods.
U-235 is slightly, but only slightly, lighter than its counterpart, U-238. A system of gaseous diffusion is used to begin the separating process
between the two isotopes. In this system, Uranium is combined with fluorine to form Uranium Hexafluoride gas. This mixture is then propelled by low-
pressure pumps through a series of extremely fine porous barriers. Because the U-235 atoms are lighter and thus propelled faster than the U-238 atoms,
they could penetrate the barriers more rapidly. As a result, the U-235's concentration became successively greater as it passed through each barrier.
After passing through several thousand barriers, the Uranium Hexafluoride contains a relatively high concentration of U-235 -- 2% pure Uranium in the
case of reactor fuel, and if pushed further could (theoretically) yield up to 95% pure Uranium for use in an atomic bomb.
Once the process of gaseous diffusion is finished, the Uranium must be refined once again. Magnetic separation of the extract from the previous
enriching process is then implemented to further refine the Uranium. This involves electrically charging Uranium Tetrachloride gas and directing it
past a weak electromagnet. Since the lighter U-235 particles in the gas stream are less affected by the magnetic pull, they can be gradually separated
from the flow.
Following the first two procedures, a third enrichment process is then applied to the extract from the second process. In this procedure, a gas
centrifuge is brought into action to further separate the lighter U-235 from its heavier counter-isotope. Centrifugal force separates the two isotopes
of Uranium by their mass. Once all of these procedures have been completed, all that need be done is to place the properly molded components of
Uranium-235 inside a warhead that will facilitate an atomic detonation.
Supercritical mass for Uranium-235 is defined as 110 lbs (50 kgs) of pure Uranium.
Depending on the refining process(es) used when purifying the U-235 for use, along with the design of the warhead mechanism and the altitude at which
it detonates, the explosive force of the A-bomb can range anywhere from 1 kiloton (which equals 1,000 tons of TNT) to 20 megatons (which equals 20
million tons of TNT -- which, by the way, is the smallest strategic nuclear warhead we possess today. [Point in fact -- One Trident Nuclear Submarine
carries as much destructive power as 25 World War II's]).
While Uranium is an ideally fissionable material, it is not the only one. Plutonium can be used in an atomic bomb as well. By leaving U-238 inside an
atomic reactor for an extended period of time, the U-238 picks up extra particles (neutrons especially) and gradually is transformed into the element
Plutonium is fissionable, but not as easily fissionable as Uranium. While Uranium can be detonated by a simple 2-part gun-type device, Plutonium must
be detonated by a more complex 32-part implosion chamber along with a stronger conventional explosive, a greater striking velocity and a simultaneous
triggering mechanism for the conventional explosive packs. Along with all of these requirements comes the additional task of introducing a fine
mixture of Beryllium and Polonium to this metal while all of these actions are occurring.
Supercritical mass for Plutonium is defined as 35.2 lbs (16 kgs). This amount needed for a supercritical mass can be reduced to a smaller quantity of
22 lbs (10 kgs) by surrounding the Plutonium with a U-238 casing.
To illustrate the vast difference between a Uranium gun-type detonator and a Plutonium implosion detonator, here is a quick rundown.