VIENNA — The control systems of Iran’s Bushehr nuclear plant have been penetrated by a computer worm unleashed last year, according to a foreign intelligence report that warns of a possible Chernobyl-like disaster once the site becomes fully operational.
Russia’s envoy to NATO, Dmitry Rogozin, also has raised the specter of the 1986 reactor explosion in Ukraine, but suggested last week that the danger had passed.
The report, drawn up by a nation closely monitoring Iran’s nuclear program and obtained by The Associated Press, said such conclusions were premature and based on the ‘‘casual assessment’’ of Russian and Iranian scientists at Bushehr.
With control systems disabled by the virus, the reactor would have the force of a ‘‘small nuclear bomb,’’ it said.
‘‘The minimum possible damage would be a meltdown of the reactor,’’ it says. ‘‘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 program. Some computer experts believe Stuxnet was 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 the malware — malicious software designed to infiltrate computer systems — hit the laptops of technicians working at Bushehr, but has denied that the plant was affected or that Stuxnet was responsible for delays in the startup of the Russian-built reactor.
The Islamic Republic is reluctant to acknowledge setbacks to its nuclear activities, which it says are aimed at generating energy but are under U.N. sanctions because of concerns they could be channeled toward making weapons. Only after outside revelations that its enrichment program was temporarily disrupted late last year by the mysterious virus did Iranian officials acknowledge the incident.