Exelon has started work uprating Byron and Braidwood as part of a plan to update a total of 800-900MWe by 2004. Nearly all of the increase will be at its 11 operating units in Illinois.

Exelon has begun a 5% power uprate at Byron 1 and 2, and slightly increased power at Braidwood 1 as the first step in that unit’s uprate plan.

Byron 1’s uprate will add 70MWe, increasing the unit’s capacity to 1245MWe. Because it has a slightly different steam generator, Byron 2 will increase output by only 40MWe, bringing its capacity up to 1215MWe. Exelon expects the uprates at both Byron units to be completed by 1 June.

Exelon plans uprates of 15-20% at Clinton, Dresden 2 and 3, and Quad Cities 1 and 2. Clinton’s planned uprate will be completed in two phases. During this year’s refuelling outage, the unit will be uprated by 70-80MWe. The second phase will add another 70-80MWe in 2004.

Dresden 2 and 3 and Quad Cities 1 and 2 will get 15% uprates by or in summer 2003.

Since dry steam is more efficient than wet steam, Exelon is upgrading moisture separators. These have already been uprated at Dresden and Quad Cities last year during refuelling outages. The same will be done at other plants over the next four years.

New cooling towers installled at Dresden over the last two years helped the plant stay at full capacity during the hottest weather. The station used to reduce power during exceptionally hot days because of low water levels in a lake that supplies cooling water.

Exelon is also installing more accurate feedwater measuring devices across its plants, allowing operators to run them closer to their peak capability.

Soon after confirming its uprating programme, Exelon said it hoped to announce construction of a new plant, likely to be a pebble bed modular reactor, within the next year. The push to be the first company to order a new plant in over 20 years follows the recent unveiling of the government’s energy strategy.