Northeast Output Snaps Longest Winning Streak Since Dec.

Northeastern nuclear-power generation declined, snapping the longest string of gains since December, after Entergy Corp. cut output to the 651-megawatt Vermont Yankee 1 reactor.

U.S. production slid less than 0.1 percent to 78,029 megawatts, or 77 percent of capacity, a fourth consecutive daily decline, according to U.S. Nuclear Regulatory Commission data compiled by Bloomberg. Output was 2.1 percent higher than the year-earlier period as 21 of 104 plants were offline.

Entergy reduced output to 55 percent of capacity at Vermont Yankee 1, about 80 miles (129 kilometers) northwest of Boston, from 98 percent yesterday. The unit is returning to service following a maintenance shutdown, said Rob Williams, a plant spokesman based in Brattleboro, Vermont.

The cut led Northeastern generation lower by 1.1 percent to 23,375 megawatts, the first retreat in seven days, according to commission data compiled by Bloomberg. Generation dropped to 25,705 megawatts in the Southeast, while production advanced in the Midwest and Western regions.

Quad Cities 1, a 867-megawatt reactor operated by Exelon Corp. about 20 miles northeast of Moline, Illinois, operated at 24 percent of capacity, compared with 11 percent yesterday. The unit is increasing to full power after a scheduled refueling shutdown, said Bill Stoermer, a spokesman based at the plant.

The advance sent Midwestern output higher by 113 megawatts to 15,862. It fell yesterday to the lowest level in almost a year, data compiled by Bloomberg showed.

Grand Gulf 1

Nuclear-power production in the Western region rose 0.8 percent to 13,086 megawatts after Entergy returned its 1,297-megawatt Grand Gulf 1 reactor 20 miles south of Vicksburg, Mississippi, to full power from 91 percent of capacity yesterday.

The unit has been undergoing scheduled control rod pattern adjustments and surveillance testing since April 5, said Mike Bowling, a company spokesman based in Jackson, Mississippi.

“Typically, those adjustments and routine tests call for a down power of varied levels over a period of several days,” he said.

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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