(CNN) -- Iranian President Mahmoud Ahmadinejad was on hand Sunday as officials at a nuclear plant took a critical step toward completing a reactor, the semiofficial Fars News Agency reported.
Workers installed two containers on the reactor at the Arak heavy water facility in central Iran, Fars said. It quoted the head of Iran's nuclear agency as saying he thought the reactor will be able to help produce medicine in 2014.
"We hope that we can go through the relevant phases and carry out the necessary tests to make sure of the proper operation of this reactor and start its full launch next year," Fereidoun Abbasi said.
Some believe Iran's nuclear program is designed to produce weapons, while Iran says it only has peaceful intentions.
"We are deeply troubled that Iran claims that the IR-40 heavy water reactor at Arak could be commissioned as soon as early 2014, but still refuses to provide the requisite design information for the reactor," Joseph Macmanus, the U.S. representative to the International Atomic Energy Agency, said last week at a board of governors meeting for the U.N.'s nuclear watchdog agency.
He also urged Iran to come clean soon about its nuclear plans and ambitions to the U.N.'s International Atomic Energy Agency.
"The window of opportunity will not remain open indefinitely," he said.
At the same meeting Yukiya Amano, the IAEA's director general, said talks between Iran and the agency are "going around in circles."
"As my report on safeguards implementation in Iran shows, the (IAEA) continues to verify the non-diversion of nuclear material declared by Iran under its Safeguards Agreement," Amano said. "However, Iran is not providing the necessary cooperation to enable us to provide credible assurance about the absence of undeclared nuclear material and activities."
The spent fuel from heavy water reactors can be reprocessed to produce weapons-grade plutonium.
Heavy water, or deuterium oxide, has the chemical formula or D20, according to Brittanica.com.