TEHRAN, Iran — Iran's first nuclear plant will begin long-delayed pilot operations on Wednesday, the state atomic energy agency said.
A nuclear official in Russia, which is helping build the plant, however, said no major milestone is expected on that day.
"The pilot stage operation of the power plant will start on Wednesday," Iranian atomic agency spokesman Mohsen Delaviz told the state news agency on Sunday.
He added that the preliminary phase will take place during a visit by Sergei Kiriyenko, the head of Russia's state nuclear agency.
The long-awaited 1,000-megawatt light-water reactor, which was built in the southern Iranian port of Bushehr with the help of Russia under a $1 billion contract, was previously scheduled to become operational in fall 2008. Some 700 Iranian engineers were trained in Russia to operate the power plant.
Rosatom spokesman Sergei Novikov, however, said no major milestone in the preparations for Bushehr's start-up is expected during Kiriyenko's visit.
Novikov said that Rosatom expects it to be a "just a working visit" and that as before, the reactor's physical start-up is expected by the end of the year. "Everything is on schedule," he told The Associated Press.
"It is a regular meeting on the site, with Russians and the Iranian organizations which are working on the project," Novikov said of Wednesday's event.
He said he could not be more specific about when the reactor could be switched on, citing uncertainty about the process of integrating what has been built recently and the existing facilities at the site.
Novikov said it was possible the "pilot stage operation," described by Delaviz, could refer to the point when the plant begins to generate electricity for its own limited use during the "pre-commissioning" period, which he said is already under way. This generation normally occurs a few months before the reactor's start-up, he said.
The plant dates backs to 1974, when Iran signed an agreement to build the reactor with the German company Siemens, which withdrew from the project after 1979 Islamic revolution toppled the pro-Western Shah Mohammad Reza Pahlavi.
In 1992, Iran signed an agreement with Russia to complete the project and work began on it in 1995.
The reactor was supposed to be completed by 1999 but has been plagued by delays.
The U.S. has long opposed the deal, citing concerns that it could help Tehran develop nuclear weapons, but it softened its position after Iran agreed to return spent the nuclear fuel from the reactor to Russia _ a measure aimed to ensure it doesn't extract plutonium to make atomic bombs.
Russia says there is no evidence that Iran is seeking nuclear weapons and has joined China in weakening Western-backed sanctions in the U.N. Security Council, arguing that punishing Tehran too harshly for its nuclear activities would be counterproductive.
The U.S. and its allies accuse Iran of using its nuclear program as a cover for weapons development. Iran has denied the claim, saying its uranium enrichment program is aimed at generating electricity.
The U.N. Security Council has passed three sets of sanctions against Iran over its uranium enrichment program, which can be used to produce both nuclear fuel and the material for weapons.
The Bushehr plant will use enriched uranium imported from Russia, rather than domestically produced fuel. Fuel deliveries began in 2007.
Tehran also plans to build a 360-megawatt nuclear power plant in Darkhovin, in the southwestern Khuzestan province that would use locally produced enriched uranium.
Associated Press Writer Steve Gutterman contributed to this report from Moscow.