Inspectors from the UN nuclear agency were expected to visit on Sunday - for the first time in more than two years - the Arak heavy-water reactor in Iran.Two inspectors from the International Atomic Energy Agency arrived in Tehran on Saturday. In November, the IAEA signed a cooperation pact with the Islamic Republic granting inspectors from the agency access to two nuclear-related sites of concern to the West - the Arak plant and the Gchine uranium mine.Reuters contributed to this report.