Iran has decided to export less heavy water because of an oversupply in the international market.
The Spokesman of Iran's Atomic Agency, Behrouz Kamalvandi, said Iran will export some 20 tons of the material annually from now on.
The amount is much less that the 70 tons of heavy water that Iran exported to the US, Russia and Oman since last year's nuclear deal went into effect in January.
International Atomic Energy Agency said in a recently-released report that Iran had exceeded its heavy water limit by 100 kilograms (about 220 pounds) over the 130 metric tons allowed.
Heavy water is used to cool reactors that produce large amounts of plutonium.
Under the nuclear deal between Iran and P5+1 group of countries,. Iran pledged to put limitations on its nuclear program in exchange for the removal of nuclear-related sanctions imposed against Tehran.
The country is not allowed to have additional heavy water reactors or accumulation of heavy water inside the country for 15 years and all excess heavy water must be made available for export to the international market, the deal stipulates. Iran sold some 32 tons of heavy water for a price of $8.6 million to the US in July.