<P> Nuclear power in the United States is provided by 99 commercial reactors with a net summer capacity of 100,350 megawatts (MW), 65 pressurized water reactors and 34 boiling water reactors . In 2016 they produced a total of 805.3 terawatt - hours of electricity, which accounted for 19.7% of the nation's total electric energy generation . In 2016, nuclear energy comprised nearly 60 percent of U.S. emission - free generation . </P> <P> As of September 2017, there are two new reactors under construction with a gross electrical capacity of 2,500 MW, while 34 reactors have been permanently shut down . The United States is the world's largest producer of commercial nuclear power, and in 2013 generated 33% of the world's nuclear electricity . </P>

In the united states nuclear energy provides which percentage of u.s. energy needs