Recent negotiations with Iran have rightly focused on the most immediately alarming aspects of its nuclear programme.
The spotlight has been on its uranium enrichment to 20 per cent purity – right on the 
cusp of being weapons grade – and the deeply buried facility at Fordow, which happens to be too small for commercial purposes but the right size for a weapons programme.
Placing exclusive emphasis on these dangers, however, obscures other worrying installations inside Iran. Frequently forgotten is the Arak research reactor, which appears to be on track for completion next year. The United Nations Security Council ordered Iran to stop building this plant because it could provide the ability to produce weapons-grade plutonium.
There are two paths to a nuclear weapon. Like all other nations that have pursued the ability to make a bomb, Iran is following both. Arak is a classic dual-use facility. It will be used for medical isotope production and other civilian purposes. But its size and character make it ideal for producing a bomb’s worth of plutonium a year. India, Israel and North Korea all used similar reactors for their first nuclear weapons.
I do not wish to sound alarmist. To render the plutonium useable in a bomb, it would have to be reprocessed using technology that Iran does not have and that it has offered to forgo. Arak is monitored by the International Atomic Energy Agency (IAEA), which would blow the whistle if Iran were to extract any spent fuel rods for reprocessing – even if Tehran could build the plant.
But what if Iran were to expel the inspectors, as North Korea did, and acquire the reprocessing technology from Pyongyang? By then, the option of a military strike on an operating reactor would present enormous complications because of the radiation that would be spread. Some think that Israel has drawn its red line for military action before Arak comes on line, which Iran says will be next year.
