Bloomberg News reported this widely-quoted story [in late 2011]:
“Nuclear physicist David Albright, founder of the independent Institute for Science and International Security in Washington and a former weapons inspector, said in an interview yesterday [14 Dec 2011] that what concerns Israel most is Iran’s plan to triple the rate of enrichment by installing new generation centrifuges at Fordo that are being tested at the Natanz site.”
“At the current rate, Albright said, it would likely take Iran till the end of 2013 to enrich enough 20 percent uranium to be further processed for use in one bomb. If Iran were to get three sets of new generation centrifuges working at Fordo and Natanz, they could produce enough material by the end of next year  that could be further enriched to weapons-grade, he said.”
” ‘Where Israel would get more nervous is if Iran started to install hundreds of advanced centrifuges underground,’ which would mean a ‘breakout capability over about six months,’ Albright said, referring to the ability to enrich uranium to weapons-grade. And at Fordo, ‘there’s no way to blow it up because it’s 90 meters under rock.’ “
What Albright is saying is that, if Iran does not choose to ramp up its production of uranium, it will nevertheless have enough 20% U-235 by late 2013. The problem with this time frame is that Iran has proven beyond any doubt that it is willing to go to great lengths to obtain nuclear weapons. The IAEA report could not be more clear on this point. See my post summarizing all that Iran has done so far: Iran’s Nuclear Missile Check List. So it is highly-likely that Iran will take whatever steps it can to increase its uranium purification rate.
Albright suggests that 3 sets of centrifuges (3 cascades) at two facilities will be sufficient to produce enough 20% U-235 by late 2012. He further states that if Iran were to ramp up its efforts further, with hundreds of centrifuges (not hundreds of cascades), they could produce enough 20% U-235 in about 6 months. The shortest time frame in which Iran could produce nuclear bombs is within the next 6 months.
Albright’s point about this shortest time frame does not assume any resources or technical capability apart from what Iran has already amply proven that it possesses. They are able to ramp up production, if they are willing. But Iran’s actions, in the course of their nuclear weapons development program over the past several years, shows that they are willing.
In an interview with CBS news, Defense Secretary Leon Panetta “suggested Iran’s nuclear program could be on a faster track than previously suspected…. It would be sometime in around a year they would be able to do it [build a nuclear weapon]….”
“Perhaps a little less. The one proviso is if they have a hidden facility somewhere in Iran,” he said.
Panetta is saying that Iran could possibly build a nuclear bomb before the end of 2012, if they tried. And if Iran has any covert nuclear facilities, of which we are unaware, then the time frame could be considerably shorter.
Panetta was criticized for making these remarks, because he does not know that Iran will definitely build a nuke in that time frame. But in my view, we should err on the side of caution. The shortest time frame that Iran could possibly build a nuclear bomb is within the next 6 months (early to mid 2012).
The Director-General of the International Atomic Energy Agency (IAEA) said that the soonest Iran could build a nuclear bomb would be in 6 to 12 months. He said this in a TV interview on 20 June 2011, about 6 months ago. That is not to say that Iran has a nuclear bomb now (Dec. 2011). But it is possible that Iran could have nuclear weapons sometime within the next six months: January to June 2012.
The IAEA report on Iran’s nuclear program, released 8 November 2011, explains in detail how Iran has already successfully researched, developed, and tested every component needed to make a nuclear bomb, except sufficient weapons grade uranium (90% U-235). The report states that Iran is known to possess over 79.7 kg of 20% U-235 from just one facility [IAEA Report, n. 15]. It would take just a couple of months to purify this amount of 20% U-235 into enough weapons grade material for one bomb.
But the same report also makes the point that we don’t know everything about Iran’s nuclear program. The report expresses concern that Iran may have covert undeclared nuclear facilities and material [IAEA Report, Annex, n. 30]. They already have sufficient 20% U-235 to process and make at least one nuke. They may have more 20% U-235 than we know. And if they have already produced some 90% U-235, they will certainly not report this to the IAEA. Iran can claim, correctly, that 20% U-235 has some uses other than as a step in making weapons grade uranium. But they can’t make the same claim once it is processed into weapons grade.
Surprisingly, it is much easier to enrich uranium from 20% to 90%, than to enrich uranium up to 20%. The length of time needed is shorter, and the complexity of the operation is reduced. It takes only a couple of months to purify 20% U-235 into sufficient 90% U-235 for a couple of nuclear bombs.
“in terms of technical difficulty, 20% uranium is nine-tenths of the way to weapon-grade material. In fact, leaked US diplomatic cables reveal that as far back as April 2009 US officials were convinced that Iran had mastered the process.” [The Guardian, Julian Borger, ‘Iran’s nuclear activity under scrutiny as evidence of weapons threat emerges’, 2 Nov 2011]
What does this all mean? Iran could build one or more nuclear weapons within six months or so. And this time frame of about six months does not take into account the possibility that Iran has more 20% U-235 than we know. Nor does it take into account the possibility that Iran may have already begun to purify the 79.7 kg of U-235 that the IAEA report states they already possess, into 90% U-235. Therefore, I conclude that Iran could possibly build a nuclear bomb in less than 6 months, and they could use that bomb against the United States as early as summer of 2012.
See my detailed analysis on this question, in my Kindle eBook:
Notes on the Apocalypse: 2012
Recent news stories have modified the situation, for the worse:
Iran is ramping up their uranium purification efforts, and boasting about it to the world. The 2013 time-frame for Iran to obtain a nuke assumed no increase in U-235 purification. With the announcements of new and more efficient centrifuges, and the newer underground facility going into production, Iran is on track to make a nuclear bomb sometime in 2012.