Exelon Corp. began a refueling shutdown at the 1,136-megawatt Byron 2 reactor in Illinois, sending Midwestern nuclear-power production to the lowest level in almost a year.
Nationwide generation retreated 2.6 percent from yesterday to 78,077 megawatts, or 77 percent of capacity, the biggest drop in eight weeks, according to U.S. Nuclear Regulatory Commission data compiled by Bloomberg. Output was 0.2 percent higher than one year ago with 20 of 104 reactors offline.
Byron 2, about 85 miles (137 kilometers) west of Chicago, halted for scheduled refueling and maintenance after operating at 100 percent of capacity yesterday, according to Paul Dempsey, an Exelon spokesman based at the plant.
Workers will perform more than 12,000 inspection and maintenance tasks and refurbish the cooling tower’s interior structure, the company said in a statement today.
“This is our second consecutive outage with a larger than normal schedule of work,” said Russ Kearney, Byron Station site vice president.
The shuttered unit led the decline in Midwestern output, which fell 6.4 percent to 15,750 megawatts, the lowest level since April 22, according to commission data compiled by Bloomberg.
Reactor maintenance shutdowns, usually undertaken in the U.S. spring or fall, when energy use is at its lowest, may increase consumption of natural gas and coal to generate electricity. The average refueling down time was 46 days in 2012, according to the Nuclear Energy Institute.