WASHINGTON, April 4: Iran was quietly making gas centrifuges at a site in Tehran that was later detected by international inspectors, a Washington-based anti-nuclear proliferation group says. The new study by the Institute for Science and International Security goes beyond the initial US claim that the network allegedly headed by Dr Abdul Qadeer Khan had supplied Iran with centrifuges needed for enriching uranium. It also contradicts media reports that Iran was using nuclear fuel supplied by the Khan network and instead says that Tehran used imported Chinese uranium fuel gas to test its centrifuges.

The Iranian centrifuge-making facility is identified as Kalaye Electric, which was established near Tehran in 1995, and in Persian it simply means ‘electric goods’.

Corey Hinderstein, a deputy director at the institute who researched the Iranian site, claimed: “The Iranians have been using the site to research, develop and manufacture gas centrifuges for uranium enrichment.”

She said Iran had to reveal the real purpose of the site when international pressure forced them to allow inspectors from the UN nuclear watchdog, the International Atomic Energy Agency, to visit Kalaye Electric in May 2003. Initially Iranians were reluctant to allow the inspectors to collect samples from the site but “they have now come clean and allowed IAEA inspectors to take samples and some of these samples had signs of uranium”, Ms Hinderstein said.

The report also claims that Iran did not acknowledge that the Kalaye Electric was a primary centrifuge research and development, and manufacturing site until operations moved to another nuclear facility called Natanz in 2002.

The IAEA reported that between 1997 and 2002, Iran assembled and tested the so-called P-1 centrifuges at Kalaye, named after those first made in Pakistan in the 1980s.

The report says Iran used 3.5 pounds of imported Chinese UF6 to test centrifuge machines between 1999 and 2002.