Atomstroiexport, Russia's nuclear power equipment and service export monopoly, is working on the $1-billion plant in Bushehr, 400 kilometers (250 miles) southwest of Tehran on the coast, which was previously scheduled to become operational by the end of 2006. That date has been set back to the second half of 2007.
"We know that Russia will participate in the tender, and hope that it will be one of the main bidders," said the source, who wished to remain anonymous.
But he said he did not know any details about the terms of the tender, except that it will be open and that all those interested will be invited to take part.
Iran has been at the center of an international dispute this year over its nuclear ambitions. Some countries suspect the Islamic Republic of pursuing a covert weapons program, but Tehran has consistently denied the claims and says its needs nuclear energy for civilian needs.