"Securing the Middle East with a Nuclear Iran?"
You see a lot of talk about this, but no real analysis of the situation. All we have at the moment is that Iran is pursuing control over their nuclear cycle for an announced development of nuclear power for power production. To do that, they need to enrich natural uranium to the level that it is useful in a power plant. Natural uranium contains about 0.7% U235 with the balance being U238. Lowly enriched uranium(LEU) is somewhere between the 0.7% and 20%. This is useful for a reactor, the higher the better. Highly enriched uranium(HEU) is above 20%. It is useful for reactors and can also be used for weapons. Weapons grade is 90% or above, lower levels can be used with a clever enough design. But once you can enrich uranium, the degree of enrichment is a function of time and effort, the procedure is the same. So let's assume that they will enrich all the way to weapons grade.
So now they have 90% uranium, how to make a bomb? Actually, this is pretty easy as long as your goal is to have something that explodes with some decent force. Take about 15 kilograms(33 pounds) in one hand, and 15 in the other, and slam them together. You will likely go out in a blaze of glory. You need to get enough atoms close enough together that the chain reactions goes critical, i.e. explodes. If you squeeze it hard and fast enough then the amount needed is smaller.
There are two basic methods to do this. One, a gun type. This is the classical Little Boy bomb. You take a cup of HEU and fire a plug of HEU into it with explosives. The other is a implosion device where a sphere of HEU is surrounded by a ball of explosives with detonators scattered over the surface, all of which is detonated at precisely the same time so the HEU sphere is crushed to a critical density before it explodes.
So how much is needed? It depends on how much you know about the physics involved. You can get the basics of a crude bomb out of public materials. Anything more advanced requires either classified information or what you learn through testing. A bog simple gun-type bomb needs 40-50 kilograms of HEU. The Little Boy bomb we dropped on Hiroshima weighed 4000 kilograms. That is big, but it can be built with a high degree of confidence it will go off with a yield of 15-20 kilotons. Smaller ones with HEU can be made, but they require a lot of knowledge of the process, which means experienced designers.
ucsusa.org
Ok, a untested bomb that, though untested, can be pretty much relied on to explode. Now how to deliver it? Now Iran does have some planes capable of delivering a bomb of this size. But in any hypothetical conflict with, say, Israel, what are the chances of it getting close enough to deliver it into one of the most heavily defended airspaces in the region? If you say "zero" you wouldn't be far off... Which leaves truck, ship or missile. Truck would be difficult, but not impossible to detect. HEU, unlike plutonium, isn't as big of a source of neutrons. But there are ways to detect it if need be. So the truck would have to evade all checkpoints to get to Israel. In a time of low tensions that might be possible to do with a single weapon, any wide scale attempt, especially during high tensions borders on impossible. Ditto with ships.
But what if the target isn't Israel, but the US or Europe? It is possible to slip a HEU bomb through in a ship that is packed with oil. Nobody is really scanning for such. But getting much more than one device in place at exactly the same time would be a logistics nightmare that more than likely would be stopped because of suspicious patterns. So we are talking about just a couple of devices. Which would mess up any port it exploded at, killing tens of thousands, if not more. A simple examination of the area would indicate if the bomb was HEU, plutonium or thermonuclear. If HEU, the only source would be Iran. If plutonium, North Korea or possibly Pakistan. If thermonuclear, Russia or China. So the source would be immediately indentifiable. And, within hours, a target with rapidly depleting targets of opportunity...
So that leaves missiles. The maximum weight that any of Iran's missiles can deliver is about 1000 kilograms.
iranwatch.org
Which means it cannot deliver a device that results from no testing. Given the rigors of launch, it pretty much rules out a gun-type device any way, launch being much like what happens when the device is activated. When Little Boy was used they didn't even load the explosives into the device until after takeoff because of the fear of a small whoopsie during takeoff.
en.wikipedia.org
Therefore, they would need to develop an implosion device. That would be better, a lot less HEU is needed, as little as 9-12 kilograms and the bomb is smaller. Safer too, because unless all the detonators are sequenced precisely right, the bomb won't undergo a fission explosion. But getting the sequencing exactly right takes a lot of research and probably involves a lot of testing to get right. At least it did for us. And the smaller you want the bomb, the more testing and refining that needs to be done.
Bottom line, to build a missile deliverable warhead that is highly likely to explode, Iran almost certainly needs to do testing or have acesss to American, Chinese, Russian, British, French or possibly Indian or Pakistani designers. Ok, Israeli too, but I wanted to keep this in the vague bounds of possiblities. With the possible exception of Pakistan, all on the list have reasons to decline helping Iran get very sophisticated weapons. Upgrading their missiles with a max. throw weight of 1000 kilograms? No problem. Developing an implosion fission device using 2 kilograms of plutonium? Nope.
Bottom line, if Iran tests, then it is time to ratchet this discussion. Until then, it is time for the diplomats. |
