U.S. Nuclear Generation Falls as Exelon Slows Two Reactors

May 24 (Bloomberg) -- U.S. nuclear-power generation dropped from an 11-week high after Exelon Corp. slowed output at reactors in Illinois and Pennsylvania.

Nationwide production fell 0.8 percent to 84,275 megawatts, or 83 percent of capacity, from yesterday’s 84,982 megawatts, which was the most since March 9, to according to Nuclear Regulatory Commission data compiled by Bloomberg. Output was 1.9 percent higher than a year ago with 14 of 104 plants offline.

Exelon Corp. reduced output at the 1,118-megawatt LaSalle 1 reactor in Illinois to 80 percent of capacity from 100 percent yesterday .

“We are performing surveillance and testing on Unit 1,” Megan Borchers, a spokeswoman at the plant 70 miles (113 kilometers) southwest of Chicago, said in an e-mail. She declined to say when it would return to full power.

Generation at Exelon’s 1,134-megawatt Limerick 1 plant, about 30 miles northwest of Philadelphia, was cut to 60 percent from full capacity yesterday. Output was lowered “this morning for planned maintenance activities” on a recirculation pump, Dana Melia, a spokeswoman at the plant, said in an e-mail. She declined to say when the work would be finished.

Duke Energy Corp. reduced production at South Carolina’s Catawba 2, which can generate 1,129 megawatts of electricity, to 48 percent from 100 percent yesterday.

Catawba Plans

Output was cut to clean condenser filters of debris, said Scott Andresen, a spokesman at the plant about 17 miles southwest of Charlotte, North Carolina. “We should be back at full power by the end of the weekend and next weekend we are going to do the same for Unit 1.”

Andresen said Catawba 1, also with 1,129 megawatts of capacity, will be reduced to about 50 percent on May 31. The unit was operating at full power today, NRC data show.

Constellation Energy Group Inc. increased output at the 862-megawatt Calvert Cliffs 2 reactor, about 38 miles south of Annapolis, Maryland, to 30 percent from 3 percent. The plant is ramping up after it tripped offline on May 21 because of equipment failure associated with the steam generator feed pump, according to the NRC.

Production at Dominion Resources Inc.’s 973-megawatt North Anna 2 unit in Virginia was boosted to 68 percent from 48 percent. The reactor restarted earlier this week after completing work.

Reactor maintenance shutdowns, usually undertaken in the U.S. spring or fall when energy use is 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.

To contact the reporter on this story: Naureen S. Malik in New York at nmalik28@bloomberg.net

To contact the editor responsible for this story: Dan Stets at dstets@bloomberg.net