Iran 'eight years' from operational nuke
President's uranium enrichment claims 'misleading'
Experts have calculated that "severe technical difficulties" in Iran's nuclear programme mean it's eight years away from an operational nuclear weapon, the Telegraph reports.
President Mahmoud Ahmadinejad declared on 9 April that the country had commenced enrichment of uranium on an "industrial scale", but scientists call this "misleading" and estimate it could take Iran four years just to produce enough weapons-grade product for a single nuke.
Norman Dombey, emeritus professor of theoretical physics at Sussex University, explained: "It's very difficult to enrich uranium. It calls for several different scientific and engineering disciplines. Iran hasn't yet shown that it has mastered the problem."
Specifically, Dombey says it could take the Islamic Republic 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, according to Mohammed ElBaradei, head of the International Atomic Energy Authority.
The current state of play is this: Iran has told the International Atomic Energy Agency that it has installed 1,312 centrifuges at its Natanz facility, which has capacity for 3,000. As and when it has the full complement, they must be "fitted together to form 18 cascades", after which operatives can introduce gaseous uranium into the centrifuges.
The centrifuges spin at high speed to separate the fissile uranium-235, which must ultimately be enriched to 90 per cent purity if it's to later go bang*.
However, Iran will have to "spin all the centrifuges inside a vacuum without any interruption for a period of about one year", during which time the smallest speck of dust in the works can ruin the whole process, requiring a complete restart. Likewise, mechanical or power failure can send months of work down the pan.
Why would anyone go for a uranium bomb?
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.
Time is a relative thing
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!
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.