In a series of reports, the Bipartisan Policy Center has been tracking the progress of Iran’s nuclear program. We calculate that, if it chooses, Iran could produce enough highly enriched uranium for a nuclear device in just 62 days using its existing stockpiles and current enrichment capability. And international inspectors examine Iranian facilities only about once every two months. This means that Tehran is approaching the ability to produce a bomb’s worth of highly enriched uranium before the international community realizes it has happened.

This timeline will contract substantially if Iran continues on its current course. Because enrichment from 3.5 percent to 20 percent requires about four-fifths of the effort to enrich from 3.5 percent to 90 percent, Tehran’s continued production of uranium enriched to 20 percent will dramatically decrease the time it would need to produce weapons-grade highly enriched uranium. Once Iran acquires more than 150 kilograms of uranium enriched to 20 percent — which could happen by early 2013 if Iran’s announced plans are realized — it would need only 12 days to produce enough fissile material for a bomb.