The International Atomic Energy Agency has always had a conflicted mandate. It is supposed to promote the peaceful use of nuclear technology while also restraining the spread of nuclear weapons.

The problem is that some peaceful nuclear technology can be too easily used to make a weapon. That dangerous duality is being pla-yed out again this week in Vienna, where the agency’s board is debating whether its staff should provide Iran with technical advice on how to safely complete construction of a heavy water nuclear reactor near the town of Arak. Tehran says it needs the reactor to produce medical isotopes. The US and the Europeans suspect that what it really wants is the abundant plutonium that can be extracted from the reactor’s spent fuel. The board needs to soundly reject Iran’s request. Anything less will only confirm Tehran’s belief that the international community is not serious about containing its nuclear ambitions.

The Bush administration needs to offer Tehran explicit security guarantees in exchange for giving up technology that could feed a nuclear weapons programme. The Arak episode is one more reminder of why the world needs to find a better way to guarantee countries the benefits of civilian nuclear technology without also dangling the temptations of nuclear weapons.