Nuclear fuel rods contain pellets of enriched uranium that provide fuel for nuclear power plants.
Iran's atomic energy agency's website says the rod has already been inserted into the core of Tehran's research nuclear reactor.
The announcement marks another step in Tehran's efforts to achieve proficiency in the entire nuclear fuel cycle - from exploring uranium ore to producing nuclear fuel - despite U.N. sanctions and measures by the U.S. and others to get it to halt aspects of its atomic work
The West fears Iran's uranium enrichment program is geared toward making atomic weapons - a charge Tehran denies.
Iran also flexed its military muscle on the same day, test-firing a medium-range, surface-to-air missile in the strategic Strait of Hormuz.
Twenty percent of the world's oil exports travel through here.
The drill could bring Iranian ships into proximity with U.S. Navy vessels in the area.
The Associated Press contributed to this report.