Iran's first nuclear power plant will undergo a critical series of tests starting Wednesday before full-scale operation begins later this year, Iranian state radio reported Sunday. The plant is a highly symbolic facet of Iran's controversial nuclear program. Iranian leaders insist the country's nuclear ambitions are peaceful, but the United States, Israel and some European nations have charged that Iran is trying to produce nuclear weapons. The long-delayed 1,000-megawatt reactor is being built by the Russian state company Atomstroiexport, which also supplies enriched uranium for the plant's operation. Iranian and Russian officials will inspect the Bushehr plant before the testing begins. During what is known as the "virtual fuel-injection test," all operations at the plant will be checked, state radio reported. "God willing, this will be an important step towards the full launch of the Bushehr nuclear power plant," Mohsen Delaviz, a spokesman for the Atomic Energy Organization of Iran, said Sunday, according to state radio. A batch of low-enriched uranium, supplied by Russia and needed to activate the reactor, will not be used during the testing. Western countries have criticized Russia over its support for the Iranian nuclear program. Russia says the plant is purely civilian and cannot be used for any weapons program. The spent uranium has to be returned, so it cannot be used for other means, Russian officials say. Russia, together with China, has weakened Western-backed efforts in the United Nations Security Council to sanction Iran over its nuclear program. Iran had stockpiled 2,227 pounds of low-enriched, or reactor-grade, nuclear fuel by late January, according to a report by the International Atomic Energy Agency that was issued Thursday. That could be enough, physicists say, to make a single bomb if the fuel were enriched to a higher level. The quantity represented an increase from earlier estimates. The IAEA published a statement Sunday that seemed intended to counter the impression that the accounting shortfall might have been a result of deliberate evasion. "Iran is cooperating well with U.N. nuclear inspectors to help ensure it does not again understate the amount of uranium it has enriched," the agency said. The issue is important because of suspicions, denied by Tehran, that it may use uranium enrichment to produce weapons. The West is also concerned the IAEA may not be able to keep track of Iran's nuclear advances. Defenders say that to weaponize its program, Iran would have to take steps such as withdrawing from the Non-Proliferation Treaty, kicking out international inspectors, breaking U.N. seals on batches of uranium and shutting down dozens of UN cameras that monitor nuclear sites across the country. "Our production of a nuclear energy program is completely within the framework or structure of international laws," said Ali Akbar Javanfekr, media adviser to President Mahmoud Ahmadinejad.