Refueling and maintenance activities at Ameren Missouri's Callaway Nuclear Plant have been completed, and the 1,190-megawatt nuclear energy center is back in service.
This was the 20th planned refueling and maintenance outage for Callaway, which celebrates its 30th anniversary on Dec. 19.
During the refueling period, which began Oct. 11, thousands of periodic maintenance activities, inspections and tests were performed. One of the largest maintenance activities in Callaway's history took place with the replacement of the original reactor vessel head, which was installed when Callaway went online in 1984. It cost approximately $150 million to replace this.
Also during the outage, which occurs every 18 months, 84 of the 193 fuel assemblies in the reactor core were replaced. Each assembly is an 8½-inch square bundle of 12-foot long metal tubes containing ceramic pellets of uranium dioxide fuel.
To help accomplish the wide range of tasks, more than 1,100 supplemental workers joined Callaway's regular workforce of about 800 employees.
Callaway generates about 20 percent of the electricity supplied to Ameren Missouri's 1.2 million electric customers and company officials said that is one reason why the company's electric rates are more than 16 percent below the Midwest average.