Nuclear Plant Uprates

Construction crews last week prepared a concrete slab to serve as a staging area for the replacement of Limerick’s six huge transformers, a $90 million job that will take about two years to complete.

The improvements to the transformers, which convert electricity for transmission on big power lines, are only one component of a complicated effort to “uprate” the plant’s output, adding 170 megawatts of generating capacity to each unit. Along with earlier upgrades, the improvements will expand Limerick’s total capacity to 2,600 megawatts – 23 percent more power than it produced when the two units were completed in 1989.

The upgrades at Limerick, and a similar project at the twin Peach Bottom reactors in York County, are part a larger Exelon Corp. plan to add up to 1,500 megawatts of capacity to its fleet of 17 reactors, which are concentrated in Pennsylvania and Illinois.

Uprates cost about $2,400 per kilowatt, which would put the Limerick upgrades in the neighborhood of $800 million. Uprates are competitive with building a new fossil-fuel or renewable plant because they require few increases to operating costs – no additional staffing or maintenance costs, just more fuel.

The initial uprate planned for Limerick is a “measurement uncertainty upgrade,” which involves installing equipment to more precisely measure the water flowing into the reactor, and therefore the quantity of steam produced, Exelon says. With more accurate metering, the plant can operate closer to its legal capacity, yielding an improvement of up to 2 percent. Limerick plans to apply to the NRC for that uprate in February.

State utility regulators have approved a plan by Entergy Mississippi to increase the output from its Grand Gulf Nuclear Power Plant in Port Gibson.
Grand Gulf’s capacity would rise to 1,443 megawatts from 1,265, a 13 percent increase. Fisackerly, in a statement released Wednesday, says the total cost, estimated at $510 million, will be shared among the joint owners of Grand Gulf.
The project’s completion is scheduled for 2012. Most of the work will be accomplished during regularly scheduled maintenance outages.

The industry’s capacity factor – a measure of how efficiently the nuclear assets produce power – has increased from 62 percent to almost 92 percent in two decades. According to the Nuclear Energy Institute, the industry’s policy arm, no other electrical generators come close. Coal-fired plants operate at 71 percent capacity; wind turbines operate at 31 percent capacity, and solar panels generate power only 21 percent of the time.

Owners also are extracting more life from their reactors by extending their 40-year operating licenses. The Nuclear Regulatory Commission has granted 20-year extensions to more than half the nation’s commercial reactors – on Monday, PPL Corp.’s two Susquehanna units in Luzerne County became the latest to get extensions. Exelon plans to apply for Limerick extensions in 2011.

Japan’s nuclear utilisation rate climbed year-on-year in November, rising for the third month in a row, as utilities increased power output ahead of winter.

The nuclear power plant utilisation rate at Japan’s 10 nuclear power companies averaged 66.6 percent in November, 8.5 percentage points higher than a year ago, the trade ministry said on Tuesday. Last month’s nuclear run rate was also 3.1 percentage points higher than in October