Nuclear Output Falls as Calvert Cliffs and Clinton Slow

U.S. nuclear-power generation fell for a third day as Constellation Energy Group Inc. and Exelon Corp. slowed plants in Maryland and Illinois.

Production decreased 0.1 percent to 87,645 megawatts, or 86 percent of capacity, the lowest level since Dec. 4, according to U.S. Nuclear Regulatory Commission data compiled by Bloomberg. Output was 3.2 percent lower than a year ago, with 14 of 104 reactors offline.

Constellation reduced the 862-megawatt Calvert Cliffs 2 to 93 percent of capacity from full power yesterday. The plant is 40 miles south (64 kilometers) of Annapolis, Maryland. Unit 1 was at full capacity early today.

Clinton 1, a 1,065-megawatt Exelon unit, dropped to 91 percent of capacity from 97 percent yesterday. The plant is about 23 miles southeast of Bloomington, Illinois.

Production slid in the Northeast and Midwest, while the NRC’s Southeast region gained 0.1 percent after dropping the most yesterday since Dec. 16, 2011. Southeastern output today was 5.8 percent lower than a year ago.

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.

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To contact the editor responsible for this story: Dan Stets at

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