A general view of the Arak heavy-water project
A general view of the Arak heavy-water project Reuters

Secretary of State John Kerry confirmed on Wednesday that Iran has removed the calandria, or central vessel, of its nuclear reactor at Arak, and it will be filled with concrete within hours.

Iranian media reported earlier this week that the Islamic Republic had removed the core of the Arak heavy-water nuclear reactor, the fate of which was one of the sticking points in nuclear negotiations between Iran and the six world powers.

"Just yesterday, the foreign minister (of Iran) reported to me that the calandria of the plutonium nuclear reactor is now out and in the next hours it will be filled with concrete and destroyed," Kerry said Wednesday, according to Reuters.

The removal of the calandria is a key part of last year's Iran nuclear deal. The deal's "Implementation Day," when Iran will start to get sanctions relief, would take place "likely within the coming days," Kerry added.

Satellite images from several years ago showed that the Arak plant was operational, raising fears that it is trying to produce plutonium for a nuclear bomb. Iran invited inspectors to visit the plant a year later, shortly after an interim agreement was signed with world powers.

Implementation of the July agreement is around the corner, despite a December 2 report from the International Atomic Energy Agency (IAEA) which concluded that Iran made a "coordinated" effort to develop nuclear weapons in the past, although the efforts apparently ended at an early stage.