News & Views item - April 2006

 

 

Nature's Assessment of "Iran Takes Steps to Go Nuclear". (April 14, 2006)

    In news@nature.com on April 13 the journal Nature give its assessment of just what the announcement by Iranian President Mahmoud Ahmadinejad that his country had successfully enriched uranium entails.

   

Iran claims to have processed a small amount of uranium so that it can be used in a power reactor; they say they have enriched the fissile uranium-235 isotope of their material to 3.5%. The same process could in theory be used to make a nuclear weapon, but this would need material to be enriched to more than 80%.

 

Iran, long known to have perhaps a few hundred centrifuges, announced that they used a network of 164 machines for their enrichment. "Iran hasn't demonstrated much more of a technical ability than it had before," says physicist Michael Levi of the Council on Foreign Relations, a non-partisan think-tank in New York City.

The Iranian president has vowed to have 3,000 centrifuges operating by the end of 2006, and says this number will eventually increase to 54,000. Tens of thousands of centrifuges are needed to make enough nuclear fuel for a power plant. Having 3,000 centrifuges doesn't make very much sense for an industrial programme, says Levi, but that number could make a handful of nuclear weapons each year.

After a large number of centrifuges enriched the uranium to more than 80% uranium-235, Iran would have to convert this uranium gas into metal, fashion it into bomb components, and assemble a package of explosives that could detonate it. Those are not trivial steps, says Levi, but they are generally considered to be easier than the first step of creating bomb-grade uranium.

"Iran is not going to have a nuclear weapon anytime soon unless it has a major hidden programme that we don't know about," says Levi. "Based on known facilities, the estimate is that Iran would take at least three years and probably several more. That is a worst-case estimate."