Published online 20 February 2009 | Nature | doi:10.1038/news.2009.115
Updated online: 26 February 2009
News: Briefing
Iran's nuclear plansDo a satellite launch and a tonne of enriched uranium add up to an arsenal?
Geoff Brumfiel
Iran would need to purifiy its uranium-235 further to build weapons.PunchstockAccording to the latest International Atomic Energy Agency (IAEA) report, released yesterday, Iran has produced around a tonne of low-enriched uranium. That number was well above the United Nations' nuclear watchdog's estimate of 660 kilograms in November 2008. Nature News examines the implications.
Where did all that extra uranium come from?
Iran says that it produced 171 kilograms of the material between November 2008 and January 2009. The rest, around 179 kilograms, appears to have been discovered during the IAEA's annual inventory of materials at Iran's uranium-enrichment facility at Natanz. The origin of the material is "a little bit of a mystery", says Jeffrey Lewis, a nuclear expert at the New America Foundation in Washington, DC. He believes that the Iranians may have misreported their production in earlier statements to the nuclear watchdog – although whether this was accidental or intentional is unknown.
I've heard that all you need is about 25 kilograms of uranium to build a bomb. Could Iran build an arsenal of nuclear weapons?
No. To build a bomb requires around 25 kilograms of a very specific isotope of uranium known as uranium-235. The naturally occurring uranium is only 0.7% uranium-235, and the process of enrichment purifies it so that it can be used in a reactor or a nuclear bomb.
Bomb-grade uranium is around 90% pure uranium-235, while reactor-grade material is typically just 3-5%. Iran has enriched its uranium to 3.49% according to the IAEA. That's pure enough to use in reactors, which is Iran's stated reason for enriching its uranium, but the concentration is still well below what you'd need for a bomb.
So what's all the fuss?
Technically, if Iran has 1000 kilograms of 3.5% enriched uranium, then it could obtain about 35 kilograms of pure uranium-235. In other words, Iran has got enough uranium-235 to build a bomb.
But first it needs to further purify its uranium-235. Iranian engineers could do that the same way that they made their 3.5% uranium, by passing their material through a cascade of spinning centrifuges that separates the isotopes from the heavier, and more common, uranium-238. In fact, enriching to about 5% is "most of the work", according Lewis.
The fear now is that Iran might be able to initiate a crash programme that could give them a weapon in a matter of a month or two.
Iran also launched its first satellite into orbit on 2 February – is that related to all this?
Initial reports suggested that the rocket used, known as a Safir-2, was a beefed-up version of a simple type of Soviet-era missile known as a scud, with a small, third stage on top. But observations by amateur astronomers now suggest that it was actually a more powerful two-stage rocket.
A rocket capable of carrying a satellite can also carry a warhead, so Iran's scientific achievement has military implications. But while the Safir-2 could get a 25-kilogram satellite into orbit, it would have a much tougher time delivering a half-tonne "gun-type" uranium warhead of the sort the country could produce with its centrifuges, according to David Wright at the Union of Concerned Scientists in Cambridge, Massachusetts. The Safir-2 would only be able to carry such a weapon perhaps 2,000 to 3,000 kilometres. "To really get longer range they have to go back and design a whole new missile," he says.
So what does this all mean?
"I think this information is only Earth-shattering if people have an outdated view of the world," Lewis says. The Iranians have already demonstrated the ability to produce rockets and uranium. The latest advances are no more significant than previous improvements, and it will be some time before the Iranians get a true nuclear capability — if that is what they're after.
Still, he adds that "time is running out". He believes that the international community must work with Iran to create a regime of inspections that can verify their activities while building trust between it and other nations.
Updated:
Iran claims to have successfully tested its 1000 MW nuclear plant at Bushehr yesterday using lead fuel rods. The reactor is expected to be fully operational later this year.
Comments
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Mahmoud Ahmadinejad accesses no more than a few warheads. Iran would be melted in reprisal for nuking a Western ally. A rich target sits 20,300 km straight up: US GPS orbits. US military operations involving navigation or targeting are inert absent GPS. Watch for booster development and some *very* dirty bombs.
20 Feb, 2009 Posted by: "Uncle Al" Schwartz Obviously I don't want that Iran makes the bomb. However, its danger is instrumentally magnified: Tehran could never stike, since retaliation would melt it (Israel has 5 nuclear armed undestroyable submarines). What is true is that Iran could no longer be attacked! In order to prevent Tehran form making the bomb, one has to negotiate, not bomb it, and accept Iran in the international community as any other State. On the other hand, Brazil has already carried through the enrichment process, and nobody has protested!
23 Feb, 2009 Posted by: Angelo Baracca Lewis is underestimating the importance of those developments. They are more than just additions to that countries national prestige. they are indicative of a future nuclear bomb building capability that may be a few years away.
24 Feb, 2009 Posted by: neil farbstein despite the obvious that it would be insane to bamb countries that have retaliatory nuclear capability, there is still the possibility that extremists will go through with a crazy option.
24 Feb, 2009 Posted by: neil farbstein "China got the bomb, but have no fears, They can't wipe us out for at least five years." --Tom Lehrer, c. 1967
24 Feb, 2009 Posted by: Michael Maxwell The most effective application would not be a direct bombing via rocket or "dirty" bomb but an EMP from just off shore from any freighter. Small yield only is necessary with a short flght and no time to react. Down goes the grid. rm
24 Feb, 2009 Posted by: robert matheny Technological discussions on this topic seem absurd. Any committed (I use that word in several senses) user can produce a very nasty dirty nuclear device easily. The one and only reliable solution to such problems is to ban the bomb. And to implement that ban. In this instance, that can only be acheived through a normallisation of political relations with Iran. "Extremists" are us: some years back Curtis LeMay wanted to "bomb the commies back into the stone age" - and McCain's rewrite of "Barbara Ann" continues the refrain. One can hardly criticise a proselytizing theocracy for "extremism" - it's their state-of-the-art. Would they be more or less extreme, I wonder, than a nation that has thousands of hydrogen bombs ready to go?
25 Feb, 2009 Posted by: simon goodman