Nuclear Output Advances to Highest Level in Almost a Week

U.S. nuclear generation increased to the highest level in almost a week as Entergy Corp. boosted output at a reactor in Mississippi and the Tennessee Valley Authority returned a Tennessee unit to full power.

Total U.S. production advanced 0.3 percent from yesterday to 93,496 megawatts, or 92 percent of capacity, the highest level since Jan. 4, according to U.S. Nuclear Regulatory Commission data compiled by Bloomberg. Output was 2.1 percent less than a year earlier with seven of 104 reactors offline.

Entergy’s 1,297-megawatt Grand Gulf 1 reactor operated at 80 percent of capacity early today, up from 56 percent yesterday. The unit, 25 miles (40 kilometers) southwest of Vicksburg, tripped offline last week when a protective relay identified a fault, said Mike Bowling, a company spokesman. There was a similar incident Dec. 29, he said.

Crews last week installed monitors to investigate the reason for the shutdown and found the relay fault was triggered by a “small piece of winding that had tapered down almost like a small tear,” Bowling, based in Jackson, said in a phone interview today. The winding “touched a bolt and that’s what tripped the plant over the weekend.”

Sequoyah 1, TVA’s 1,148-megawatt reactor near Chattanooga, Tennessee, returned to full power after operating yesterday at 98 percent.

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 43 days in 2011, according to the Nuclear Energy Institute.

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