An Iranian security guard directs media at the Bushehr nuclear power plant in 2010. Iran and negotiators from six world powers are in Vienna trying to work out a long-term deal on Iran's nuclear program. Vahid Salemi/AP hide caption

itoggle caption Vahid Salemi/AP

Inspectors from the International Atomic Energy Agency are scheduled to visit Iran's heavy-water reactor in the city of Arak on Sunday as part of an international deal on the country's nuclear program. Hamid Forutan/EPA/Landov hide caption

itoggle caption Hamid Forutan/EPA/Landov