Iran's heavy water nuclear facility near the central city of Arak. File picture: Hamid Foroutan, ISNA

Tehran -

Iran said on Wednesday it has started to modify its Arak heavy water reactor and limit plutonium output, a cause of Western concerns over the country's nuclear programme.

“Modification of the heart of the Arak reactor is in the process of being carried out by our experts... to ease the worries of certain countries,” said Ali Akbar Salehi, who heads Iran's nuclear programme, quoted by ISNA news agency.

“Foreign ministry officials have been informed of the technical details of these modifications,” Salehi said.

The reactor in Arak, 240km south-west of Tehran, could in theory provide Iran with weapons-grade plutonium.

But the 40-megawatt reactor, whose construction is being supervised by the UN nuclear watchdog, is solely for research purposes, notably medical, according to Tehran.

Iranian officials have said its design will be modified to produce one kilogram of plutonium a year instead of eight kilograms as originally planned.

Under an interim agreement with world powers which came into effect in January, Iran agreed to scale back part of its nuclear programme in return for a partial lifting of Western sanctions.

A final deal has a target date of November 24.

Tehran denies Western charges that it seeks nuclear weapons, insisting it is pursuing atomic energy purely for peaceful purposes. - Sapa-AFP