.... it's inertia that causes the heavier gas molecules to move towards the outside of the cylinder.

http://regentsprep.org/Regents/physics/phys06/bcentrif/default.htm

I can't get all worked up about 8 years. I'm still waiting in my bunker until we get the 'all clear' on those missiles the Iraqis are supposed to be able to deploy in 45 minutes. They still haven't found those buggers yet, so they're still out there ... somewhere.

but there are better and faster ways to get weapons grade uranium. The same technology used for aluminium can be applied to the dust of the natural rock. It requires multiple tons of ore and there is a slight chance to start a reaction during the process, but it's faster and cheaper. There is an old soviet technology that used this method. If iran takes the risk and goes that way, they might have a working bomb within a year. (Footnote: if the usa+world stopped threatening them they might do something useful instead.)

"..two years to "master the process" of running the gas centrifuges required for uranium enrichment. After that, a further two years would be required to knock up enough to make a bomb. Thereafter, it would have to build a warhead suitable for delivery via missile, giving a total of eight years.."

So, two years to master the processing technology, another two to generate enough weapons-grade uranium for a warhead plus four years (inferred from the text) to build a warhead to carry it.

Suppose they develop and build the warhead in parallel to manufacturing the nuclear material and just swap out the big lump of blu-tac in the warhead for the real radioactive deal when it's ready?

Assuming the stated four year development time for the nuclear material and a four year build time for the warhead the whole thing could be ready to go in four years, half the time suggested by the article.

What am I missing?

So all it takes to completely ruin this process is a single little bomb landing nearby, releasing some dust and shaking the centrifuges a little? At which point they have to restart from the beginning.

Sounds to me like it'll be more then easy enough to stop Iran months after they've started running the centrifuges.

They (the Iranians) aren't talking about industrial-scale enrichment to weapons-grade. They're talking about large scale production of fuel-grade uranium, which only needs to be about 5% U235, not the 90% this article is frothing about. For one, they daren't talk openly and directly about aiming to produce nuclear warheads and all the official proclamations are about the right to pursue the nuclear power generation option.

Have a 1 day black-out every 3 months or so for the facility. The process takes up to a year to get enough, and needs to be restarted if interrupted.

Hell of a lot easier than marching thousands of troops into a hostile country, and try to run the country without speaking the language, knowing the religion, local politics, and making a policy of not hiring locals.

Now where did that happen...

8 years if they make one from scratch, but if they can persuade a hard up russian scientist or the pakistanis to sell them some weapons grade Plutonium, then they could be tooled up far sooner..

How is everyone so sure they aren't pretending to have a half built Uranium refinery? Is Ahmadinejad just taunting the U.S. so that they attack and he says to the world how unjust it all is, or is he suddenly going to appear on a press release as a nuclear power and drop a nuke on Israel to show he has no qualms? If North Korea can buy nuclear technology and be up and running in record time, what is to say a fanatic like Ahmadinejad can't?

Correct me if I'm wrong, but don't the Iranians deny they're making any bombs at all? Despite the fact that much of the world fails to believe this, doesn't that make it somewhat unlikely that they were implying their 'industrial enrichment' was for the construction of arms? I would think they were commenting on production for power production, which I think requires less enrichment (although I'm not too sure). Anyway, they didn't claim that their enrichment was yielding results, whatever scale it was on.

If all they need is a device capable of spinning the Uranium at high speed , would they not be better off with a Dyson or something?

How about a nice EMP Blast? Wipe out there power and all?

Then they could televise the workers at the plant spinning the Uranium in the centrifuges like them people who spin 30 plates in wooden sticks at the circus.

Hmmm, copywrite that before Endemol takes it!!!

Just take a trip to London, there has to have been at least one suitcase nuke handed in to London Victoria's lost propertly department!

Hey this is awful, I'll be having nightmares!

I mean just imagine: some megalomaniac country with a tin-pot religeous nutcase of a leader who obviously has no qualms about invading other countries on spurious grounds might get hold of nuclear weapons! We gotta do something!

What? Oh...that already happened? They already used their nuclear weapons on civilian targets? They already did invade someone else's country on spurious grounds? But I thought we had 8 years to prepare! What? Oh...not Iran...

Wake up and smell the coffee (but try not to choke on the pretzel...)

The Manhattan project took three years to do it in 1945 when no-one knew how to make a bomb. The resources may have been far greater than those available to Iran, but the knowledge of how to do it is already there: the rest is only engineering. Are the Iranians so much less competent engineers with the facilities available to them now than the Americans were in 1943 with the facilities available to them then? Frankly I doubt it. The good professor seems to have made a good case to say that the Atom bomb wasn't dropped on Hiroshima in 1945, like the Moon landings it was a hoax...

I didn't realize that Hiroshima and Nagasaki were hit with nuclearr warhead tipped long range missiles....

Obviously if you're going to just drop it out of a bomber, you can skip the 4 yrs missile development. And if cost is no issue obviously they did shrink the other 4 years down into 3 years. So what's the problem with the article again? Sorry JimC, no cookie for you.

As I remember history, when the USSR deployed an atom bomb, the CIA (or whatever intelligence agency was operational then) was saying that they (the Soviets) were a "year away". When the Iranians do a test, we will all say they are N years (pick your N) away. Not much has/will change. We will only know for sure when we observe the Boom!

There's only one reason I can think of. U235 can be made into a cannon bomb like the Little Boy dropped on Hiroshima. Because it uses more than one critical mass of uranium it is guaranteed to explode. If Iran wants a fool-proof bomb the cannon is the best way to go - South Africa did the same when it developed its bomb.

The alternative is to use an implosion bomb - like Fat Man dropped on Nagasaki - which can use uranium or plutonium. This bomb is much harder to engineer, but it uses less than a critical mass of fissile material - which allows a country to get the bomb faster - assuming it can do the math. Bearing in mind the Fat Man plans were leaked to the Russians and copied by the British, French and Chinese, it's almost certain the Iranians could replicate the design.

Uranium in an implosion bomb is perfectly acceptable, its a bit more massive than a plutonium bomb, but it does the job well. Pakistan's weapons are almost certainly all fuelled by uranium, but everyone else has gone the plutonium route.

Why? It's easy to make once you have a reactor. You don't even need to enrich your uranium fuel; just copy the Magnox design helpfully declassified by the British, load it with fuel and remove the rods every 90 days or so to stop too much Pu240 and Pu241 developing in the spent fuel. Then its just a matter of BSc rare earth chemistry to separate the plutonium from the unburned uranium and the fission products.

The Iranians are building light water reactors which aren't nearly as good for bomb-grade plutonium as they don't support on-line refuelling, but as the British and Americans discovered in the 1950s, even reactor-grade plutonium makes a big bang - just not such a big bang.

If I was a power-mad dictator that's the way I'd do it.