In a generally insightful and timely article appearing in Slate, journalist and defense policy expert Fred Kaplan debunks “the nutty theory that Iranian nukes are a good thing.” He echoes some of the arguments I’ve offered over the several years this blog has been in existence. Kaplan, however, errs later in his article when he claims that we have a reasonable amount of time between now and when Iran can amass enough weapons grade U-235 for a bomb that it can fit inside a reentry vehicle on top of a missile.
To support his claim, Kaplan references this Spring, 2008 paper by Alexander Glaser to assert:
…[O]nce they’ve enriched their uranium to the level of 20 percent - it will take a year or more to enrich it further to the 80 percent or 90 percent needed to build bombs.
This is a gross oversimplification, probably derived from Glaser’s concluding section, which states:
The results based on the cascade simulations predict that more than 100 kg of weapon-grade HEU can be produced in one year with 3.5%-preenriched material and a capacity of 5000 SWU/yr, which is equivalent to about 2000 P1-type machines.
Let’s parse Glaser’s conclusion. Iran today is known to have at least 6,000 P1-type centrifuges, not 2,000 (the 2000 was probably a reasonable number nearly 3 years ago when the article was written), and the amount of material needed for a single nuclear weapon is considerably less than 100 kg. How much less? I addressed this in When will Israel attack?, from May 2009:
Using a neutron reflector (like beryllium) along with implosion, a much smaller amount of U-235 is needed for a critical mass than with a gun design and no neutron reflector. This is less than 20 kg, at high enrichment levels.
If we put this information together using Glaser as our source, it means that 2,000 P1 centrifuges can produce 5 small tactical nukes in one year starting with low-enriched uranium (LEU) feedstock. Moreover, now that Iran has 3 times that number of centrifuges, if it has enough LEU, it could produce 15/year. That amounts to one tactical nuke in a little less than a month or one strategic nuke in just over a month.
Glaser’s very detailed analysis on separative work and the capabilities of the P1 centrifuge essentially validates the back-of-the-envelop analysis I gave in When will Israel attack?:
To get from natural uranium to 95% enriched, bomb grade uranium (known as high enriched uranium – HEU) takes 6.14424 tSW. To take the same amount of natural uranium to 3.8% enrichment (known as low enriched uranium – LEU) requires 3.97689 tSW. Most of the work (around 64%) expended is to get from 0.711% to 3.8%. With 6,000 or so centrifuges running at max efficiency, it should take only a few weeks to go from 3.8% to 95%.
The fact is that a correct reading of Glaser validates my “threshold” or “breakout” argument.:
So long as the centrifuge operation and LEU UF6 stockpile are compliant with IAEA safeguards, there is no “immediate” threat, or so the argument against preemption goes. Militating against this is the speed with which the first bomb can be produced – a few weeks if the Natanz facility is converted to bomb making.
So, if Glaser (Kaplan’s source) and I are right about Iran’s potential to rapidly produce enough material for nuclear weapons, why has there been no preemption? Kaplan says:
…[I]f they get to that point [of having enough material for a bomb], it’s another matter still to turn the material into bombs and then to fashion and miniaturize the bomb to fit onto a missile. This is rocket science.
To which I would add that it is over fifty-year-old “rocket science”. It is “rocket science” that, as reported several years ago by Jane’s, is based upon proven Soviet reentry vehicle (RV) designs suitable for a 1 MT warhead. Moreover, there is very good evidence that Iran has already tested an implosion design that goes far beyond the crude, first generation “laptop” design. Given all of this, it is reasonable to assume that when Iran produces its first weapon it will almost certainly be a 1 megaton device that can be carried in its redesigned Soviet-era warhead.
Iran has thus far played the international game brilliantly, aided by the foreign policy ineptitude of what Charles Krauthammer has called the “clownish” Obama administration. Contrary to Kaplan, there is very little time to deliberate on what to do about Iran. In any case, the only country with the will and capability to take out Iran’s nuclear program is Israel, so a discussion of what the international community together or the U.S. alone will do is moot. The real question is, what is the Israeli government waiting for?