Statistics compiled by the Nuclear Energy Institute show the U.S. nuclear fleet running at high efficiency, underscoring the reactor sector's role as a steady contributor to the electric grid. According to NEI's U.S. Nuclear Generating Statistics page, which draws on U.S. Energy Information Administration data, the fleet's capacity factor reached 93.0 percent in 2023, the most recent full year in the published series.

Total nuclear generation that year came to roughly 775.4 million megawatt-hours, supplying an 18.2 percent share of all U.S. electricity generation. Summer generating capacity across the operating fleet stood at 95,773 megawatts.

The 2023 capacity factor continues a run of consistently high performance for U.S. reactors that stretches back more than two decades. NEI's dataset shows the fleet's capacity factor climbing from the 50 to 60 percent range common in the 1970s and 1980s to a level that has remained above 90 percent in most years since the late 1990s, a shift driven by shorter refueling outages, improved maintenance practices, and fewer unplanned shutdowns.

NEI separately notes that today's 94 licensed reactors generate almost 20 percent of the nation's electricity, and that industry surveys show utilities pursuing license renewals at 20 plants and power uprates at 29 units, moves aimed at squeezing more output from the existing fleet as electricity demand rises.

Source: Nuclear Energy Institute -- https://www.nei.org/resources/statistics/us-nuclear-generating-statistics