Fears of Chernobyl-style disaster as computer virus hits nuclear site

The control systems of Iran's Bushehr nuclear plant have been hit by a computer worm, according to a foreign intelligence report that warns of a possible Chernobyl-like disaster once the site becomes fully operational.

The report, drawn up by a nation closely monitoring Iran's nuclear programme, said that with control systems disabled by the virus, unleashed last year, the reactor would have the force of a "small nuclear bomb".

"The minimum possible damage would be a meltdown of the reactor," it said. "However, external damage and massive environmental destruction could also occur … similar to the Chernobyl disaster."

The virus, known as Stuxnet, has the ability to send centrifuges spinning out of control and temporarily crippled Iran's uranium enrichment programme. It is believed to have been the work of Israel or the United States, two nations convinced that Iran wants to turn nuclear fuel into weapons-grade uranium.

Iran has acknowledged that laptops of technicians working at Bushehr were affected, but has denied that the plant was affected, or that Stuxnet was responsible for delays in the start-up of the Russian-built reactor.

It is reluctant to acknowledge setbacks to its nuclear activities, which are under UN sanctions because of fears they could be channelled towards making weapons.