I've always imagined it would be the fission material, but I'm probably wrong.
After
(a) obtaining sufficient quantity of enriched uranium or plutonium,
one must also
(b) correctly design and build the non-nuklur starter explosive package:
Little Man Atomic Bomb - Bing Images
and try to make the new baby smaller than the bomb that was dropped on Horoshima:
Models of Little Boy & Fat Man Atomic Bombs from WWII | Flickr - Photo Sharing!.
A "Little Boy" size bomb is too big for convenient terrorist smuggling or for launching atop Iran's SCUD-derived missiles. SCUDS -- not all that much technologically evolved than 1944 vintage V-2/A-4's.
It's possible that the latter-day Persians lack the techno-industrial capability to manufacture their own gunpowder, much less an A-bomb.
This Iranian A-bomb stuff may be all hype coming from both sides -- both the Iranians and the Israel lobby.
Last edited by Modern Elmo; 24th Jan 2012 at 03:01.