A Chinese company will sign a contract with Iran on Sunday to redesign the nuclear facility in the city of Arak, located southwest of the capital Tehran. The fate of the facility was one of the main points of contention during the negotiations ahead of Iran's nuclear deal with Western powers. Once the facility is redesigned it will not be able to produce weapon-grade plutonium. Iran claims that the heavy water at the facility is only used for the production of isotopes for medical treatments.