Ameren Missouri is asking for federal approval to operate its Callaway nuclear plant through at least 2044.
The St. Louis-based utility filed a 1,500-page application with the Nuclear Regulatory Commission seeking a 20-year extension of the plant's operating license, which expires in 2024.
The utility said the application took more than three years to prepare.
"We evaluated every system, structure and component," said Cleveland Reasoner, vice president of engineering for the plant.
Ameren said 71 of the nation's 104 commercial power plants have already received license extensions.
The NRC typically takes about two years to review license extension applications.
The 1,190-megawatt Callaway plant near Fulton, Mo., has been operating since 1984 and provides about 20 percent of the electricity supplied to Ameren's Missouri customers.
Read more from Jeffrey Tomich, who covers energy and the environment for the Post-Dispatch. Follow him on Twitter @jefftomich and the Business section @postdispatchbiz.







