Iranian officials portrayed the expanded U.N. access as further sign it seeks to work with the West.
Under the plans, announced at a joint news conference, Iran would allow inspectors a first-time visit of its key Gachin uranium mine on the Gulf coast and give broader access to the heavy water facility being built in the central city of Arak.
Heavy water reactors use a different type of coolant to produce a greater amount of plutonium byproduct than conventional reactors.
Inspectors from the U.N.'s International Atomic Energy Agency, or IAEA, have already visited the reactor site but seek more extensive examinations.
