What is a nuclear power uprate?

How it works

When the U.S. Nuclear Regulatory Commission (NRC) licenses a commercial reactor, it sets a limit on the heat the reactor core may produce. The agency's backgrounder on uprates says a plant needs NRC permission to raise that limit. To reach a higher output, a utility typically refuels with slightly more enriched uranium or a larger share of new fuel. That produces more heat and more steam for the turbine. Pipes, pumps, generators and transformers must be able to handle the higher power level.

The NRC describes three types:

• Measurement uncertainty recapture uprates, under 2%, come from measuring reactor power more precisely.
• Stretch uprates, typically 2% to 7%, usually involve changes to instrument settings but no major plant modifications.
• Extended uprates have been approved for increases as high as 20%. They usually require significant changes to major equipment such as turbines, main generators and transformers.

A plant applies by asking to amend its operating license. The public has 30 days to comment and 60 days to request a hearing. NRC staff issue a safety evaluation with their decision.

Why it matters

An uprate gets more electricity out of a plant that already exists. The NRC says utilities have used uprates since the 1970s. As of January 2022, it says, it had approved 171 of them. They added about 8,030 megawatts (MW) of electric generating capacity, it says, roughly the equivalent of eight new reactors.

The Department of Energy's UPRISE initiative, described in March 2026, cites rising electricity demand, including from data centers. It aims for 5 gigawatts (5,000 MW) of additional nuclear capacity by 2029 through uprates, restarts of shut-down plants and related steps.

Where things stand in 2026

The NRC's list of expected uprate applications was last reviewed or updated on September 8, 2026. Its summary table counts 31 uprates that plant owners expect to apply for from 2026 through 2032, about 2,421 MW of electric capacity. The detailed list below that table has 30 entries. An expected application is not an approval.

On October 6, 2026, Google and Constellation announced a 20-year power purchase agreement. It is to fund upgrades adding 890 MW at 11 reactors in Illinois, Pennsylvania and New Jersey. The first is expected by 2028. Until a project is approved where required and finished, its added megawatts are planned capacity, not power on the grid.