(Reuters) - The future scope of Iran's uranium enrichment programme and the fate of its Arak reactor - projects the West fears could yield atom bomb fuel - must be agreed if a decade-old dispute over Tehran's atomic activity is to be finally settled.
Both issues are expected to be on the agenda during a March 18-19 meeting between Iran and six world powers - the United States, France, Germany, Britain, China and Russia - in Vienna. Iran says its nuclear work is peaceful.
The aim is to reach a comprehensive agreement by late July that would define the permissible size of Iran's nuclear programme in exchange for a lifting of sanctions that have severely hurt the Islamic Republic's oil exports.
Here is a brief overview of the key issues involved:
- Western powers have in effect abandoned idea that Iran must halt all its enrichment of uranium, which they fear may be aimed at developing atomic bombs, but want it curbed.
- Iran says it refines uranium to fuel nuclear power plants, rules out closing Natanz and Fordow enrichment facilities.
- It now has nearly 10,000 centrifuges spinning at supersonic speed to increase the ratio of the fissile isotope.
- Number should be cut to low thousands - Western experts
- United States and allies want to deny Iran any capability to quickly dash for a nuclear bomb.
- Iran is developing new centrifuge models at Natanz.
- Modern machines could enrich uranium faster.
- Iran says it has right to technology for civilian use.
- Interim accord allows Iran to continue existing R&D.
- But powers will likely seek strict limits on R&D.
- West fears planned heavy water research reactor could yield plutonium, potential bomb fuel.
- Iran says Arak designed to produce medical isotopes.
- Western experts say the reactor could be changed to ease bomb fears, for example by reducing power or changing fuel.
- Iran has suggested it could modify plant; no details.
- U.N. nuclear watchdog investigating suspicions Iran may have researched how to build an atomic bomb. Tehran denies it.
- Western officials say Iran must address allegations as part of settlement of broader dispute. But unclear exactly how.
- Iran wants punitive measures lifted quickly.
- But powers likely to do so only gradually under any deal.
(Reporting by Fredrik Dahl, Justyna Pawlak, Parisa Hafezi and Louis Charbonneau; editing by Ralph Boulton)