Limerick Generating Station receives $120M equipment upgrade

The absence of a vapor plume from one of 's two 507-foot cooling towers is usually a sign that something of note is happening at the nuclear power plant.

In late February, it was symptomatic of of the station's Unit 2 generator. A more typical example is the station's current annual refueling outage, when almost 2,000 additional personnel swarm over the site to perform various maintenance tasks.

The current refueling outage, which began on March 28, has been busier than usual.  As the company prepares to apply this summer for a 20-year extension of the Limerick facility's operating license from the Nuclear Regulatory Commission (NRC), it is completing the replacement of three massive new transformers, the first to be installed since the power station was built.

"We put in three brand new transformers. They're in their spots and we're doing the final testing, the hookups. It's a $65 million capital investment," said Joseph Szafran, Site Communications Manager for Exelon Nuclear.

Assuming the company's application to the NRC is approved, the two generating units will be licensed to operate until 2044 and 2049, respectively.  The new transformers have a lifespan of 20 to 30 years, which will theoretically allow them to operate well into that timespan.

"We wanted to make that long-term investment," Szafran said. "It's one of the largest capital investments we've made in the history of the Limerick Generating Station."

Szafran said that after tests are completed, the station will also be capable of generating an additional 34 megawatts of power. The new capacity should be available by mid-May. Szafran said the new transformers actually permit the company to increase the station's output by a more substantial margin.

"Having bigger transformers allows us, if we choose, to add up to 200 additional megawatts on each unit. As a company, we're still looking at whether it's cost-effective and it makes sense to do it," Szafran said.

The annual refueling outage, when workers perform an estimated 12,000 tasks on the plant's systems, was a natural time to schedule the transformer replacements, Szafran said.

"A lot of little repairs and small projects have to be done, and there are a lot of inspections we have to do," Szafran said.

According to Szafran, the transformer replacement project involved about 200 workers.

"Typically, with a refueling outage, we would have people here a week before. But with the transformers, they've been here for about a month and a half. They had to move the three old transformers out and move the three new transformers in," Szafran said.

Getting the three 30-ton transformers into place required a logistical ballet that began more than two years ago, when manufacturer ABB visited the site to take the measurements of the pads where the previous transformers were situated.

A railroad spur that leads from the nearby railroad into the rear of the facility had been largely unused since the plant was built in the 1970s.  It had to be completely rebuilt to accommodate the weight of the transformers, which were transported to the site via rail, project manager John Miller said. Miller placed the total cost of the project at about $120 million.

"It's not a big open location where you've got lots of room to move around," Szafran said. "It was really choreographed. Everything had to be done in a certain order."

The old transformers, with the exception of one unit that's destined to be refurbished and retained as a spare, sit on giant metal pallets in a shallow concrete corral, awaiting the bids of scrap metal dealers.

Miller said the process of replacing the transformers on Unit 1 at the station is in the early planning stages. Those upgrades are expected to be completed in 2014.

Download the movie