Hmmm... sure makes you wonder what they’re up to.
I’m not a physicist but I wonder if a nuke of any real yield is possible with only 20% enriched Uranium. My understanding is that Uranium is generally used for (and limited to) the cannon-type weapon, as opposed to Plutonium being needed for the spherical-implosion type weapon. This already limits the yield even with 80%+ enriched uranium. I wonder if the cannon-type can even reach critical mass at only 20%?
We’ll see, I guess.
http://www.guardian.co.uk/world/2009/feb/19/iran-iaea-united-nations-nuclear-weapon
The IAEA report on Iran surprised many proliferation experts because, it recorded a dramatic jump in Iranian stockpiles of LEU at the enrichment plant at Natanz. In its last report in November, the IAEA estimated that Iran had produced 635 kg of LEU, based partly on Iranian government figures.
The agency now estimates that Iran had produced 839 kg of LEU by November, and that Iran had reported producing a further 171 kg in the following two months - a total of 1010 kg. The Iranian LEU has less than a 4% concentration of the fissile isotope Uranium 235. To make weapons grade HEU, with a concentration of 80-90%, it has to be further enriched, by being passed through massed ‘cascades’ of centrifuges.
“Do they have enough LEU to produce a ‘significant quantity’ of HEU [enough for a bomb]? Yes, if you count the U235 atoms then they do have a significant quantity of HEU,” a senior official close to the IAEA said. “But it is theoretical and they would need to use their full capacity to do so. They are not there yet. If they were to build another clandestine facility, then that would be different.”
I don’t buy it at all. They are enriching uranium to 20% U-235.. hardly the contentractions needed for a bomb. I call shenanigans.... I dont doubt their intentions, but I seriously doubt their technical ability. I don’t think They will have a bomb any time soon, even the simplest Little Boy style bomb (the uranium gun bomb) would need at least 80% enrichment for them to get it to work....
2.5-3.5% enrichment is enough to drive a chain reaction.
This is what is typically used in power plants.
The isotopes used to enrich the naturally occuring uranium ore are uranium 235 and plutonium 239.
Natural uranium (yellowcake) contains about 0.7% U235.