Iran will start loading its Russian-built nuclear reactor with enriched uranium fuel in early October, months later than had originally been announced.
Vice President Ali Akbar Salehi maintained the delay had nothing to do with, adding that the plant's systems hadn't been affected.
At the, Salehi said loading the fuel into the reactor core would take place over two weeks and the plant would then produce electricity two months later in November. He gave no reason for the new delay.
"We hope to load the fuel into the Bushehr reactor by early October and the necessary groundwork for this is coming together, God willing, so it (the fuel) will be completely put in place in the heart (of the reactor) by November," he told the semiofficial ISNA news agency. "The heart of the reactor will begin beating.
If it still takes two months to hook the 1,000-megawatt light-water reactor up to the electricity grid then won't be until early 2011 that begins powering Iranian cities.
The plant has experienced numerous delays since it was first commissioned from the German company Siemens by Iran's U.S.-backed shah in 1974. The project was abandoned after the 1979 Islamic revolution and was only revived in 1995 when Russia agreed to complete it - again after many delays.
The plant has stood outside the current controversy over Iran's nuclear program since Russia will be providing the fuel for the plant and supervising its disposal - a model that the U.S. has indicated could work for other areas of the country's atomic development.
World powers are concerned that Iran wants to use aspects of its civil nuclear power program as a cover for making weapons, particularly its uranium enrichment facility in Natanz.
Enriching uranium to low levels produces nuclear fuel, but at higher levels can produce the material for a weapon.
Western leaders fear Iran's enrichment labs could one day churn out weapons-grade material. Iran claims it has no interest in nuclear arms, but refuses to give up the right to make its own fuel.
Iran has some of the world's biggest oil reserves, but lacks refinery capacity to meet domestic demand and must repurchase fuel on international markets. Nuclear power is seen as both a goal to meet power needs and an important technological achievement for the Islamic government.
On Sunday Iran announced that a computer worm capable of seizing control of industrial plants had affected some personal laptops of Bushehr employees as well as thousands of machines around the country.
Salehi insisted on Wednesday that the main systems of the plant itself were untouched.
"This contamination has not reached our main system. It was detected in some personal laptops and necessary measures were taken in this regard. Our main system is clean," he said.
The destructive Stuxnet worm has surprised experts because it is the first one specifically created to take over industrial control systems, rather than just steal or manipulate data.