VIENNA Iran has been experiencing years of problems with equipment used in its uranium enrichment program and the Stuxnet computer virus may be one of the factors, a former top U.N. nuclear inspections official said.
Olli Heinonen, who stepped down in August as head of the U.N. nuclear watchdog's inspections worldwide, said there may be many reasons for technical glitches that have cut the number of working centrifuges at Iran's Natanz enrichment plant.
"One of the reasons is the basic design of this centrifuge ... this is not that solid," Heinonen, a former deputy director general of the International Atomic Energy Agency (IAEA) and now a senior fellow at Harvard University, told Reuters on Friday.
Asked about the Stuxnet virus, he said: "Sure, this could be one of the reasons ... There is no evidence that it was, but there has been quite a lot of malfunctioning centrifuges."
Security experts have said the release of Stuxnet could have been a state-backed attack on Iran's nuclear program, which Tehran says is designed to produce electricity but which Western leaders suspect is a disguised effort to develop nuclear bombs.
Any delays in Iran's enrichment campaign could buy more time for efforts to find a diplomatic solution to its stand-off with six world powers over the nature of its nuclear activities.
Iran has tentatively agreed to meet with a representative of the powers early next month, for the first time in over a year.
Earlier this week, experts said new research showed definitively that Stuxnet was tailored to target the kind of equipment used in uranium enrichment, deepening suspicions its aim was to sabotage the Islamic Republic's nuclear activities.
Centrifuges are finely calibrated cylindrical devices that spin at supersonic speed to increase the fissile element in uranium so that it can serve as fuel for nuclear power plants or, if refined to a much higher degree, for atomic bombs.
The Islamic state's P-1 centrifuges, adapted from a smuggled 1970s European design, have been plagued by breakdowns since a rapid expansion of enrichment in 2007-08. In September, an IAEA report said the number of producing centrifuges had fallen to 3,772 from 3,936 a few months earlier. It did not give a reason.
But Iran is testing an advanced, more durable model able to refine uranium two or three times faster, and says it intends to introduce the model for production in the near future.
Heinonen said the P-1 centrifuge was quite brittle and prone to outages. He also cited other quality problems and "poor workmanship" as possible factors.
"They have some problems but you don't know what the real reason is for those problems and there may be many reasons."
Stuxnet, a malicious computer worm of unknown origin that attacks command modules for industrial equipment, is described by some experts as a first-of-its-kind guided cyber missile.
New research by cyber security company Symantec unearthed evidence that apparently supports the enrichment sabotage theory, pointing to tell-tale signs in the way Stuxnet changes the behavior of equipment known as frequency converter drives.
A frequency converter drive is a power supply that can alter the frequency of the output, which controls the speed of a motor. The higher the frequency, the higher the motor's speed.
"They have had some problems with the frequency converters ... but that is a way back," Heinonen said, citing Iranian media information from a few years ago.
(Editing by Mark Heinrich)