Even if the new sanctions against Iran prove effective at stopping an Iranian bomb, security analysts will not be able to breathe a sigh of relief. Eben Harrell in Time, April 8, 2010, explained the global distribution of highly enriched uranium:

All told, over several decades, the five permanent members of the U.N. Security Council distributed some 44,000 lbs. (20,000 kg) of HEU — enough for 800 nuclear weapons — to around 50 countries as diverse as Australia, Jamaica and Vietnam. Although that figure is a drop in the bucket compared with the estimated 4.4 million lbs. (2 million kg) of HEU in weapons and storage in the U.S. and Russia, the Atoms for Peace HEU is of particular concern because it is used in civilian reactors that are often poorly guarded and vulnerable to theft. As William Potter, director of the James Martin Center for Nonproliferation Studies at California’s Monterey Institute of International Studies, points out, “If you are a terrorist, you don’t necessarily go where there is the most material. You go where the material is most accessible.”

The story quotes Graham Allison hyping the threat and John Mueller downplaying it.

Today, reading this piece, I’m leaning toward Allison’s view over Mueller’s (who nonetheless supports reducing HEU stockpiles around the world). Unfortunately, the National Nuclear Safety Administration, a US government agency, has met some difficulties in achieving its task of reducing HEU globally:

So far, the NNSA has removed a total of 5,935 lbs. (2,692 kg) of fissile material from 37 countries and has its sights on 4,190 lbs. (1,900 kg) more….But many countries see HEU-fueled research reactors as symbols of prestige and don’t necessarily share U.S. and Russian concern that fissile material may fall into terrorist hands. Canada and South Africa, which both have large stockpiles of HEU, argue they need it to make medical isotopes profitably. Politics comes into play too: poor relations between Ukraine and Russia have hampered efforts to move Ukraine’s large stocks of HEU to Russian facilities.

Anecdotal evidence suggests those states should be worried:

[I]n November 2007… two teams of armed attackers stormed Pelindaba, a supposedly secure facility that houses hundreds of kilograms of weapons-grade uranium in South Africa. The attackers gained access to the facility’s control room and shot an emergency-services officer in the chest. They fled without making any effort to steal the nuclear material, and the reason for the break-in and the attackers’ identity remain a mystery.

So, don’t break out the champagne just yet.