Exelon to add 'new reactor' through uprates

12 June 2009

US utility Exelon has launched a series of power uprates of its reactors, which in total will add between 1300 and 1500 MWe of additional generating capacity, equivalent to a new reactor, within eight years.


Quad Cities (Exelon)
An uprate at Quad Cities is the first of many planned (Image: Exelon)
Exelon operates the largest nuclear fleet in the USA and the third largest fleet in the world. The company's ten plants - comprising 17 reactors - currently represent some 20% of the US nuclear industry's power capacity.


The first of the uprates - adding a further 38 MWe of capacity at the Quad Cities plant in Illinois - was officially confirmed last week following equipment upgrades at the plant.


Uprate projects are also underway at Dresden and LaSalle in Illinois as well as the Limerick and Peach Bottom plans in Pennsylvania. These uprates are expected to account for almost one-quarter of the new generating capacity. Additional uprate projects at nine other Exelon reactors, beginning in 2010, will add the remainder of the new capacity by 2017.


Exelon said assuming an additional 1500 MWe of capacity were added, the uprates "would displace 8 million tonnes of carbon emissions annually that would otherwise come from burning fossil fuels."


Charles Pardee, Exelon Nuclear's president and chief nuclear officer, said: "With these uprates, we will be able to produce the equivalent output of a new advanced nuclear reactor, and we'll bring it to market in a timeframe commensurate with the fastest new construction." He added, "These uprates are a critical component of Exelon 2020, the company's plan to eliminate the equivalent of its 2001 carbon footprint by 2020."


Pardee noted, "We have a proven record of achieving additional output at our plants through equipment upgrades and efficiency improvements. Nuclear uprates are safe, economical and add to the long-term safety and improved efficiency of a nuclear plant."


Uprates and upgrades over the past decade have already added some 1100 MWe of additional capacity at Exelon's plants, the company said.


Uprate options


According to Exelon, "Uprate projects improve the efficiency and increase electricity output of a nuclear generating unit through upgrades to plant equipment. The projects take advantage of new production and measurement technologies, new materials and learning from a half-century of nuclear power operations."


The US Nuclear Regulatory Commission NRC, which oversees uprate projects, recognises three categories of power uprates: 

  • 'Measurement uncertainty recapture' power uprates, which involve implementing enhanced techniques for calculating reactor power and can typically increase reactor capacity by up to 2%;
  • 'Stretch' power uprates, which usually involve changes to instrumentation settings but are within the design capacity of the plant and can typically add up to about 7% capacity; and
  • 'Extended' power uprates, which involve significant modifications to major plant equipment and can result in up to 20% capacity increases.

Since 1977, the NRC has approved some 124 nuclear power plant uprates, representing about 5640 MWe of added capacity.