What have the Iranians Got?

In a recent post Wretchard of the Belmont club talks about suitcase nukes and Iran. The good news is I think we can write suitcase nukes off the list of nightmare scenarios (see here for details why). So the question becomes what CAN the Iranians do. For examples we can look at others that have broken out of the treaties (or never were signatories) and see what they've got. The other place to look would be early US, UK and Soviet capabilities.

Our first candidate is the Pakistanis. We have two data points Chagai-1 at an estimated
9-12 KT yield and Chagai-2 at 4-6KT. Pakistani claims for these devices were in the 35KT
range (see here ). A.Q. Khan (The head of the Pakistani Nuclear program) claimed these were boosted weapons (Fission weapons with tritium injected to boost the yield). If they were they worked poorly as the originally quoted yields (from seismic data) are more in line with a much cruder U235 based gun bomb, and Chagai-2 hints at a less than successful test. The Pakistanis have set off no further tests so we're out of luck trying to estimate their current capabilities (the tests were in 1998).

The Indians are another example where some test data exists, as well as their statements
Their current repertoire is said to include:

* a pure fission plutonium bomb with a yield of 12 kt;
* a fusion boosted fission bomb with a yield of 15-20 kt, made with weapon-grade plutonium;
* a fusion boosted fission bomb design, made with reactor-grade plutonium;
* low yield pure fission plutonium bomb designs with yields from 0.1 kt to 1 kt;
* a thermonuclear bomb design with a yield of 200-300 kt.

This is a much more sophisticated set of options and looks more like a Late '50s to early '60s US or Soviet selection. The numbers are probably far reduced from the quantities the US and USSR had in that time period, but even if it's two orders of magnitude less we're talking tens to low hundreds of weapons.

Looking at the Soviet program its first weapon (Joe-1) was basically a clone of the US Fat Man weapon (the same as used at the Trinity test and in the attack on Nagasaki) and was tested in 1949. Their first boosted/fusion weapon shot was the Sakharov's "layer cake" design four years later in 1953. And their first true fusion weapon was tested in 1955.

If we look at the US program it starts with the MK 1 (Little Boy) and Mk 3 (Fat Man). Pretty much we used almost solely implosion based pure fission weapons until we get to fusion weapons testing in 1952 with deployment by 1954. Then we start creating boosted fission weapons. Our progression probably went that way because without a good understanding of fusion you can't model or predict the results of boosting. That is less of an issue today as much of that physics is well understood. However, the engineering details are probably tightly held secrets of the atomic powers so to do boosting well you're going to need some testing to get that critical data.

Given that the likely scenario is that Iran will go for a enriched uranium gun type weapon (say like the early US MK1 only less crude) as this is the easiest to make. It is also probably the plans they're most likely to have particularly given A.Q Khan's proclivities for selling the Pakistani atomic secrets. It will be a large weapon somewhere between the US MK 1 (8900 lbs) and some of our early IRBM warheads (The MK 7 at 1645-1700 lbs or the W-7 at 900-1100 pounds). Given the Pakistani weapon was intended as a warhead we're probably looking at the lighter end of that spectrum, the likely Pakistani delivery vehicle is the shaheen-1 (or shaheen-2) with quoted payloads of a metric ton (~2200 lbs for us geezers that still think in the English system). This is not a suitcase weapon but a panel truck or shipping container weapon. If they push hard they can have boosted or fusion weapons within 4-5 years. These don't necessarily get any smaller, they just are considerably more destructive. So next time I'll think aloud about the delivery methods for these nasty heavyweights.

Tregonsee (L2) signing out for now...