How Many Nuclear Reactors Are There in the US?

So, when we talk about nuclear reactors in the US, there are around 90 commercial reactors currently operating. These reactors are spread out over roughly 50 nuclear power plants, mainly located near large cities or industrial areas to provide electricity efficiently. Each reactor generates a significant amount of energy, helping to power homes, businesses, and even critical infrastructure. Nuclear power is known for producing a steady supply of electricity without the air pollution linked to fossil fuels, which makes it pretty important for the country’s energy mix. Most people don’t see reactors up close, but they play a big role behind the scenes. Safety measures are really strict to keep everything running smoothly and protect the surrounding communities. So, although nuclear reactors might seem complex, they are essential parts of how energy is generated in the US today.

The United States hosts a significant number of nuclear reactors, with around 90 commercial reactors currently operational across approximately 50 nuclear power plants. These reactors are primarily light-water reactors, which use ordinary water as both a coolant and a neutron moderator to sustain the nuclear fission chain reaction. The fundamental mechanism involves uranium fuel rods undergoing controlled fission, releasing heat that generates steam to drive turbines and produce electricity.

From a practical standpoint, these reactors provide about 20% of the nation’s electricity, underscoring their role in a stable, low-carbon energy portfolio. The reactors are strategically located near population centers or industrial hubs to minimize transmission losses and optimize grid stability. Each facility integrates multiple safety systems designed to manage reactor temperature, control fission rates, and contain radioactive materials, reflecting stringent regulatory oversight by the Nuclear Regulatory Commission.

For example, the Palo Verde Nuclear Generating Station in Arizona, the largest in the US, operates three reactors producing over 3,900 megawatts collectively, enough to power millions of homes. The reactors’ steady energy output contrasts with intermittent sources like wind and solar, highlighting their importance in meeting continuous baseload demand.

Considering the aging infrastructure, many reactors have undergone life-extension programs, which involve upgrading critical components to maintain safety and efficiency beyond their original licensing periods. This ensures that nuclear energy remains a viable and integral part of the US electricity generation mix while supporting efforts to reduce greenhouse gas emissions. This combination of operational scale, technological sophistication, and regulatory framework characterizes the US nuclear reactor landscape today.

The United States is home to 93 operational nuclear reactors, spread across 55 power plants, making it the country with the largest number of commercial nuclear reactors globally. These reactors are predominantly light water reactors (LWRs), divided into two main types: pressurized water reactors (PWRs) and boiling water reactors (BWRs), which together account for nearly all U.S. nuclear capacity. PWRs use high-pressure water to transfer heat from the core to a secondary loop where steam is generated, while BWRs produce steam directly in the core, simplifying the system but requiring stricter water chemistry controls to protect turbine components.

These reactors rely on uranium-235 as their primary fuel, enriched to 3–5% to sustain controlled fission—a process where atomic nuclei split, releasing energy that is converted into electricity through steam turbines, following principles of thermodynamics and electromagnetism. Their combined output constitutes about 20% of U.S. electricity, providing a stable baseload power source with minimal greenhouse gas emissions, a critical role in balancing the intermittency of renewable energy sources like wind and solar.

A key distinction from other nations is the U.S. fleet’s age and diversity; many reactors have operated for 40+ years, with licenses extended to 60 years, demonstrating the durability of nuclear systems when maintained with rigorous engineering standards. This contrasts with countries like China, which prioritizes newer, higher-capacity reactors, though the U.S. is also exploring advanced designs, including small modular reactors (SMRs), to complement its existing infrastructure.

Common misconceptions include overestimating the number of reactors by confusing them with cooling towers—tall, visible structures that dissipate excess heat but are not part of the reactor itself. Another misunderstanding is equating reactor count to risk; the U.S. fleet’s safety record, supported by the Nuclear Regulatory Commission’s oversight and passive safety features (e.g., emergency core cooling systems), underscores that proper engineering and regulation mitigate hazards effectively.

The fleet’s significance extends beyond energy: it drives innovation in fuel recycling, materials science, and carbon-free industrial processes, reinforcing nuclear power’s role as a cornerstone of sustainable energy strategies. By integrating nuclear physics with mechanical and electrical engineering, these reactors exemplify how complex systems can deliver reliable, low-carbon power at scale.

As of mid-2025, the United States operates 94 nuclear reactors across 30 states, housed within 54 nuclear power plants. These reactors, predominantly pressurized water reactors (PWRs) and boiling water reactors (BWRs), generate electricity through controlled nuclear fission of uranium-235. In this process, neutrons collide with uranium nuclei, splitting them into smaller isotopes while releasing heat and additional neutrons. This chain reaction is sustained via moderators like water or graphite, which slow neutrons to optimize fission efficiency, while control rods (e.g., boron or cadmium) adjust reactivity to maintain stability. The heat produced is transferred by coolant systems to produce steam, driving turbines that supply approximately 19% of U.S. electricity and 30% of global nuclear-generated power, illuminating millions of homes and businesses daily.

Beyond electricity, U.S. nuclear reactors underpin critical infrastructure. They enable low-carbon industrial processes, such as hydrogen production for steel manufacturing and desalination for water-scarce regions, while supporting naval propulsion in submarines and aircraft carriers. Medically, reactor-produced isotopes like cobalt-60 sterilize medical equipment, and molybdenum-99 (parent of technetium-99m) facilitates cancer diagnostics, treating over 50,000 patients daily. The sector also employs 87,000 workers, fostering high-skilled jobs in engineering and safety management.

The U.S. nuclear fleet’s longevity—averaging 42 years of operation—reflects advancements in aging management and safety upgrades post-Three Mile Island (1979). However, challenges persist: 15 reactors have closed since 2013 due to economic competition from natural gas, prompting federal initiatives like the Civil Nuclear Credit Program to subsidize at-risk plants. Looking ahead, the U.S. aims to quadruple nuclear capacity to 400 GW by 2050, prioritizing small modular reactors (SMRs) for remote areas and advanced designs like sodium-cooled fast reactors to recycle nuclear waste. This evolution underscores nuclear energy’s dual role as a cornerstone of decarbonization and a catalyst for innovation in global energy security.