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by Laura Fletcher and Amber Armentrout
As the US needs a greater supply of clean energy to support AI applications’ demand for electricity, more organizations propose relying on nuclear power.
For example, tech giants Google and Amazon have announced plans to support data centers with nuclear energy, and tech companies are currently the leading buyers of renewable energy. Meanwhile, many environmentalists have said that the benefits of nuclear power outweigh the risks (waste, safety, and costs).
How Many Nuclear Power Plants Are in the US?
Currently, nearly 20% of the US’ power comes from nuclear. While nuclear power expanded fairly rapidly through 1990, it’s slowed since then.
Almost 91 GW of nuclear power were added in the US from 1969 through 1990, but only 5.5 GW are currently planned between now and 2037. Live Power monitors over 65 GW of the existing nuclear facilities across Independent System Operators (ISOs) including PJM, MISO, ERCOT, NYISO, NEISO, and CAISO.
Source: Yes Energy’s Infrastructure Insights
How Many Nuclear Power Plants Are in the US?
Source: Yes Energy’s Infrastructure Insights
As of 2024, the US has 54 commercial nuclear power plants in 28 states. Illinois has the most nuclear power plants with 12, followed by Pennsylvania with 11.
While the US is a leader in nuclear power, not many new nuclear power plants are currently in active development.
In 2024, two new nuclear reactors came online in Georgia – Plant Vogtle Units 3 and 4 – the first reactors to come online in decades. Owned by Georgia Power Company and others, each reactor can power 500,000 homes and businesses.
What’s a Small Modular Reactor (SMR)?
Small modular reactors (SMRs) are advanced nuclear reactors that can create up to 300 MW of electricity per unit.
Like existing nuclear reactors, SMRs use nuclear fission to create energy. However, they are much smaller and require less fuel. They’re also modular, meaning companies can create and assemble them in factories, transporting them as units to their final locations.
Why Are SMRs Significant?
Despite their size, SMRs can create significant amounts of low-carbon energy, and they’re less costly to produce than traditional nuclear reactors, which require significant capital. They’re also more scalable and flexible regarding location because they require less land mass.
Companies can install SMRs on the power grid or off the power grid, providing energy for commercial endeavors or residential areas.
In terms of safety, many SMRs rely on passive systems that don’t need human intervention to shut them down. These systems count on physical phenomena such as gravity and natural circulation to turn off reactors, which can lower the potential for unsafe releases of radioactivity into the environment.
SMRs in the News
No commercial SMR has been built in the US yet. However, the US has opened applications for $900 million in SMRs.
Large tech companies are looking to use SMRs to power data centers and artificial intelligence. Both Google and Amazon have announced agreements with companies developing SMRs.
How Does Nuclear Power Work?
Like a coal-fired plant, nuclear power plants use closed-loop steam cycles to spin turbines. The difference is that nuclear fission provides the heat input to create steam to spin the turbines in nuclear power plants.
Nuclear fission is the splitting of atomic nuclei.
Uranium 235 is the most common fissile (easily split) material. When a neutron hits the uranium 235 nucleus, it splits, releases energy, and emits a few free neutrons. If enough uranium 235 is in one place, the free neutrons cause a chain reaction. A little bit of spontaneous fission occurs naturally, so you just need to assemble enough uranium 235 to start this chain reaction.
This chain reaction is a powerful source of energy when it’s controlled. If it’s not controlled, it creates a runaway chain reaction
People prepare nuclear fuel for use in a reactor by molding uranium into pellets, then sealing them inside metal tubes made of zirconium alloy creating fuel rods. They combine fuel rods in bundles of about 200 and then gather about 150 bundles to form the nuclear reactor core.
They insert control rods into holes in the reactor core made of boron carbide, which can absorb enough free neutrons to prevent and control the reaction.
How Does a Nuclear Power Plant Work?
There are two types of reactors – a pressurized water reactor (PWR) and a boiling water reactor (BWR).
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A pressurized water reactor
About two-thirds of the nuclear reactors in the US are pressurized water reactors. In these reactors, the core is immersed in cooling water in a reactor vessel (40 feet tall with nine-inch-thick steel walls). The water stays at such high pressure that it can’t boil even though it’s at 600 degrees Fahrenheit (heated by nuclear fission). It pumps the pressurized water from the reactor vessel through a steam turbine and back to the reactor. This is the primary loop (there’s a secondary loop for safety).
That steam turbine drives an electric generator. The steam condenses and circulates through the plant cycler.
Just like in the pressurized water reactor, the water in the boiling water reactor heats from nuclear fission. However, like its name suggests, in the boiling water reactor the coolant water does boil. It also has just a single loop as opposed to a primary and secondary loop.
In comparison to the PWR, the control rods enter from below instead of from above, where gravity can help drop them to stop the reaction if needed.
Conclusion
Nuclear power plants are capital-intensive to build. While nuclear energy growth has slowed, it still serves an important place in the electricity generation mix, alongside renewables, gas, and coal.
Nuclear serves as reliable baseload power, typically running at 100% capacity for 18 months or more between refuelings.
Want to learn more about power generation and trading in power markets? Explore our series Power Markets 101.
About the author: Laura Fletcher is on the Yes Energy product team as an associate product manager. Prior to joining the team, Laura studied environmental engineering at Georgia Tech. She started working with energy data as a college intern and she has worked on various consulting projects, annual market forecasts, client relations, and database management.
