Iranian and Russian engineers began loading fuel Saturday into Iran's first nuclear power plant, which Moscow has promised to safeguard to prevent material at the site from being used in any potential weapons production. After years of delays, the fueling of the Bushehr plant in southern Iran marks the startup of a facility for energy production that the US once hoped to block as a way to pressure the country to stop separate nuclear activities of far greater concern. There have not been strong objections to the Bushehr plant itself as there have been with Iran's separate efforts at other sites to accelerate uranium enrichment – a process that makes the fuel for power plants but which can also be used in weapons production. Even as Iran's nuclear chief said the plant demonstrated the country has only peaceful aims, he celebrated it as a defiant “symbol of Iranian resistance and patience” in the face of Western pressure. “Despite all pressure, sanctions and hardships imposed by Western nations, we are now witnessing the startup of the largest symbol of Iran's peaceful nuclear activities,” Ali Akbar Salehi told reporters inside the plant. It is the enrichment work that has been the target of four rounds of UN Security Council sanctions. Russia, which helped finish building Bushehr, has pledged to prevent spent nuclear fuel at the site from being shifted to a possible weapons program. After years of delaying its completion, Moscow says it believes the Bushehr project is essential for persuading Iran to cooperate with international efforts to ensure Iran does not develop the bomb. The United States, while no longer formally objecting to the plant, disagrees and says Iran should not be rewarded while it continues to defy UN demands to halt uranium enrichment. On Saturday, a first truckload of fuel was taken from a storage site to a fuel “pool” inside the reactor building under the watch of monitors from the UN's International Atomic Energy Agency. Over the next two weeks, 163 fuel assemblies – equal to 80 tons of uranium fuel – will be moved inside the building and then into the reactor core. Workers in white lab coats and helmets led reporters on a tour of the cavernous facility. It will be another two months before the 1,000-megawatt light-water reactor is pumping electricity to Iranian cities. The Bushehr plant is not considered a proliferation risk because the terms of the deal commit the Iranians to allowing the Russians to retrieve all used reactor fuel for reprocessing.