Exelon operators performed around 14,000 work activities, including equipment upgrades, extensive safety inspections and tests, and other plant upgrades while the unit was offline.
Quad Cities generating station vice president Tim Hanley said the power plant equipment is continuously kept up to date with the latest technology and maintained to the very highest levels.
"We meticulously disassemble, inspect, reassemble and test the various reactor components to ensure the continued reliable operation of the facility," Hanley said.
The upgrades will allow the facility to continue providing clean, safe and reliable electricity for another two-year operating cycle.
Exelon commenced unit 2 refueling outage on 19 March 2012.
With both units at full power, the facility can produce enough carbon-free electricity for about one million homes.
