Thursday, March 26, 2009

Iran Nuclear Nonsense

MI chief: Iran has crossed nuclear bomb threshold in Haaretz.

From a nuclear engineer's point of view (at least that's what my degree was in), what's in this article is total nonsense.

Military Intelligence chief Amos Yadlin told lawmakers on Wednesday that Iran has "crossed the technological threshold" for making a nuclear bomb.

Ooooh. Sounds scary. But, notice there's no detail in there. Just a scary statement. If you read further, and if you have your brain engaged, you'll find its nonsense.

The article then swerves into a side issue about how the evil Iranians have developed a 'surface to surface' missile capable of carrying nuclear weapons. But that has nothing to do with the headline or the first quote. I'll return to that point later.

Then we get to the roll-on-the-floor-laughing part ....

According to Yadlin, the bottleneck in Iran's nuclear weapons program was in obtaining fissionable material.

No kidding?

That's like saying, the main bottleneck to cooking dinner tonight is that there is no food in the house. Oh, we can see alarming preparations towards cooking dinner. We can tell they've tested the gas burners on the stove. And we feel they could have dinner ready in 20 minutes once they obtain actual food.

But hey, without the food, there ain't gonna be no dinner. And, likewise, the main obstacle to building a nuclear weapon is always going to be 'obtaining fissionable material'.

Oh, and here's the fun part where the Israelis decide to tell you that they've been lying their rear's off to you all along.

The Iranians enrich between one and two kilos of low grade uranium, Yadlin said. However, once they decide to bring that to weapon's grade enrichment levels (93%) they could produce the amount needed for a bomb within several months to a year.

Note that the Israeli Military Intelligence chief says 'once they'. But, the Israelis have been screaming for years now that the Iranians have already been doing this. Now, the Israeli Military Intelligence chief is clearly saying that they haven't been, but that they might decide to do it. Gee, I guess its a good thing we didn't already bomb Iran based on the Israeli assertions that the Iranians were building a bomb.

This by-the-way, is in total agreement with what the IAEA has been saying all along. That there is no evidence that the Iranians have ever gone beyond the 4% or so enrichment needed to fuel a nuclear power reactor.

The Israelis don't seem to be able to keep their lies straight. In today's 'You-should-be-very-scared' story, they managed to admit they've been lying all along.

One last note. The article acts like to go from the 4% levels of enrichment to 93% levels of enrichment, its just like putting something in the microwave for 5 minutes. Its not nearly that easy. 'Enrichment' means trying to separate atoms that are nearly identical except for the weight of three additional neutrons in one atom over the other. If I gave that difference in weight in grams, it would be an incredibly small number. And I mean like a decimal point then 20 or so zeros before you get to the numbers sort of small amount of weight in even milligrams. They are trying to separate one thing that weighs almost nothing from something else that weighs just the tiniest bit more than almost nothing. Remember, they are trying to separate molecules of gas based on weight. They do this by spinning this around in a centrifuge.

The trick is, that you could have imperfections in your system that might allow you to get to 4%, but that would never let you get anywhere near 93%. This is a very tricky task, to spin atoms of a gas to one end of a centrifuge, then pull those atoms, and only those atoms out of the centrifuge and separate them. Each run through a centrifuge only 'enriches' by a tiny amount. Quite likely, if the Iranians were to try to go to 93%, they would discover flaws in their system that stop them at a lower level. At least that's what's happened to everyone else who's tried to do this, as far as I know. Those flaws aren't insurmountable, but its likely to be a 'try it - it didn't work - why didn't it work - oh fix this - try it again' sort of process. Ie, it doesn't just happen because someone throws a switch.

And all of this would take both a long time and all of those thousands of centrifuges the Iranians claim to have. Which means this, if we have IAEA inspectors going to the facilities, there is no way they could do this in secret. The US built a massive facility in Oak Ridge and ran thousands of centrifuges for months to do this during the Manhattan project.

In other words, there is no reason to be scared at all. If the Iranians were to go down this path, the whole world would know it months before they ever got there.

One more last note. When they say 'surface-to-surface missiles that can carry nuclear warheads', this is obviously dependent on the size of the nuclear warheads. That's the part of nuclear weapon design that takes some skill. Its simple to make the dang thing blow up. The trick is to make it small enough to fit on top of a missile, and still blow up. Go find pictures of the first American bombs, they were huge, and needed the entire bomb-bay of a WWII super-bomber to carry them. No way they'd fit on top of a missile.

So, the key question is, how big would be the nuclear bomb that would go on this missile? I suspect that what the Israelis are really saying is that the Iranians have a missile that would carry a modern American nuclear weapon, which the Americans have been designing on for 60 years to make a warhead small enough to fit on top of it.

This in no way means that the Iranians, who've never even exploded a test nuclear warhead of any size, can design and build a nuclear weapon to fit on top of this missile.

No comments: