US power utility Constellation is to invest $800m in new equipment to increase the output of its Braidwood and Byron NPPs in Illinois. “These investments in our world class nuclear fleet will allow us to generate more zero-carbon energy with the same amount of fuel and land, and that’s a win for the economy, the environment and Illinois families and businesses who rely on our clean energy,” said Constellation President & CEO Joe Dominguez.

Each NPP comprises two 1,120 MWe Westinghouse four-loop pressurised water reactor units. The Braidwood units began commercial operation in 1988 and the Byron units in 1985 and 1987. The investment will increase output by approximately 135 MWe, the equivalent of adding 216 intermittent wind turbines to the grid, according to Environmental Protection Agency data. The project is expected to create work for thousands of skilled union workers during construction while expanding economic activity for surrounding businesses in the plant communities, Constellation said.

Constellation, formerly Exelon Generation, owns and operates 21 nuclear reactors and also has an operating interest in Salem NPP units 1&2. Braidwood and Byron were among the Illinois NPPs that were saved from premature retirement by passage of the state Climate and Equitable Jobs Act in 2021. Congress also passed the Inflation Reduction Act (IRA) in 2022, which provides a base level of support for nuclear energy nationwide.

Support for nuclear in the IRA has made extending the lives of U.S. nuclear assets to 80 years more likely assuming continued support. It has caused Constellation to examine nuclear uprate opportunities that were cancelled a decade ago due to market forces. Tax credit for the production of new carbon-free electricity helps to make these investments economic, Constellation noted.

The Braidwood and Byron uprates will involve replacing the main turbines with state-of-the-art, high efficiency units. Constellation expects to see increased output at the stations as early as 2026, with the full uprated output available by 2029. Work will take place in stages during scheduled refuelling outages.

This latest development follows Constellation’s announcement of significant progress at its clean hydrogen project at Nine Mile Point NPP in upstate New York, and the start of work to renew operating licences at the Clinton and Dresden NPPs in Illinois. Constellation said it expects to apply to the US Nuclear Regulatory Commission (NRC) for licence renewal in 2024. If the licences are granted,

Clinton’s single boiling water reactor (BWR) could operate until 2047 and the two Dresden BWRs until 2049 and 2051.

Image: The Braidwood (left) and Byron (right) nuclear power plants (courtesy of Constellation)