Talks on deal implementation
Sunday's inspection comes just weeks after Iran clinched a landmark deal with world powers under which it will freeze or curb some of its nuclear activities in return for limited relief from crippling international sanctions.
The interim six-month accord struck in Geneva on November 24 aims to build trust and buy time for diplomacy to solve the decade-long standoff over Iran's nuclear work.
Quoted by the ISNA news agency, senior Iranian negotiator Abbas Araqchi said Tehran and the so-called P5+1 group -- the United States, Britain, France, China and Russia plus Germany -- are to start discussions on implementation of the deal in Vienna.
The two-day meeting at the level of experts begins on Monday, with several such gatherings to follow in coming months "so that the Geneva deal can hopefully achieve its objectives," Araqchi added.
The Arak reactor has been one of several sticking points, with UN Security Council resolutions calling on Iran to suspend work there.
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Based on the agreement in Geneva, Iran is obliged to "not commission the reactor or transfer fuel or heavy water to the reactor site" or instal remaining components at the unfinished facility.
It should also increase cooperation with the IAEA, under the "roadmap" agreement signed last month after years of unsuccessful negotiations.
The IAEA will now also have access to the Gachin uranium mine, near the Strait of Hormuz in the southern Gulf.
Kamalvandi said Sunday an IAEA visit to Gachin could be discussed next week.
"Details have not been discussed, but it is highly likely that the framework and a timeline for a visit to Gachin will be discussed in the talks in Vienna on Wednesday," he told ISNA.
Another site causing international concern is the Parchin military facility where the IAEA suspects Iran may have experimented with atomic weapons development.
Tehran has so far denied the agency access to Parchin, saying its military nature puts it off-limits.