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Detailed planning sets stage for massive maintenance job

JOHN SEELMEYER

Four large sheets of paper from an easel pad stretch across a wall of a conference room at NV Energy’s Tracy Generating Station, each of them jammed with printed step-by-step plans for a three-week shutdown for major maintenance of two big units at the plant.

The job is so complex, in fact, that NV Energy for the first time contracted for a scheduler to work exclusively on coordination of the tasks of about 100 workers from northern Nevada and locations across the country.

The reason for the urgency: The two generating units produce 578 megawatts of power, more than half the capacity of the plant on the south side of Interstate 80 about 17 miles east of Reno.

And while NV Energy scheduled the maintenance shutdown for the autumn months when demand for power is at its lowest in northern Nevada, the utility has some important economic reasons to move quickly.

The combined-cycle generating units are among the most efficient on NV Energy’s system about a third more efficient than older-style generating units and the utility brought less-efficient generation at Fort Churchill near Yerington back onto line during the shutdown.

Hence, the detailed preparation.

“It’s taken a monumental planning effort,” says John Frankovich, production manager at the Tracy Power Station.

Months ago, workers began running small video cameras deep into the generating systems to see if they would encounter unexpected problems that might required delays to order and install additional equipment.

Last week, two weeks into the shutdown, the plans had held to schedule as workers were entering the home stretch of their final days on the job.

Workers rebuilding a turbine the size of a jet engine were following detailed illustrations on a nearby wall.

Warning signs cautioned them to empty their pockets before starting work, and told them to account for every tool they used. Even a small foreign object inside the turbine could result in massive damage when it’s restarted.

A couple of hundred yards to the south, another team of workers was rebuilding giant steam valves each about the size of the kids’ table at Thanksgiving that control 1,000-degree steam that’s under pressure of 1,800 pounds per square inch when the plant is in operation.

Jesse Murray, plant engineering and technical services manager for the plant, said northern Nevada contractors account for much of the employment on the job. Other firms with specialized skills traveled to the site from Utah, Kentucky and elsewhere.

Simply providing for another 100 workers on the site presented a host of logistical questions, said Frankovich. Spaces needed to be found for workers to eat their lunches. Temporary restrooms dot the plant site.

Ordinarily, about 15 workers per shift oversee the plant’s operation a total of about 65.

The maintenance shutdown has been scheduled for this autumn almost since the time the facility entered commercial operation in 2008, said Jesse Murray, plant engineering and technical services manager for the plant.

NV Energy is taking advantage of the scheduled maintenance to upgrade some of the combustion hardware in the plant.

In the combined-cycle technology used in the two generation units that are undergoing maintenance, natural gas fires the two big turbine generators. The exhaust from the two units is recaptured to power a separate steam generator.