Skip to Content

From Atoms to Electricity: A Step-by-Step Guide to How Nuclear Energy Works

Nuclear energy is a clean source of energy for producing electricity, with the United States producing up to 30 percent of the world’s nuclear power.

Nuclear power is created through a process called nuclear fission, which happens when energy is released from the nucleus of an atom.

Keep reading for a detailed step-by-step guide to how nuclear energy works, including the process of nuclear fission and the advantages and disadvantages of nuclear power.

how nuclear energy works

Methods of Production

Nuclear power is generated by using uranium, which is a metal that is mined as an ore. Uranium is usually found in large quantities.

Nuclear reactors work similarly to methods used in other power plants, but they use nuclear fission reactions instead of fossil fuels to generate heat.

The uranium used in nuclear energy production is called uranium-235, and it is used because the atoms are the easiest to split. This type of uranium is rare, so it has to be enriched using natural uranium until the fuel contains 2 to 3 percent uranium.

Nuclear Fission

The nuclear energy used throughout the world today is produced through nuclear fission.

Nuclear fission is a reaction that happens when the nuclei of atoms split, releasing energy. Each time an atom splits, energy is released in the form of heat and radiation.

The heat from this reaction is then converted into electricity, which is used to power homes, businesses, etc.

Nuclear Fusion

Nuclear fusion happens when the nuclei fuse together. This method is not used in any of the world’s nuclear power plants, because it is very difficult to sustain a fusion reaction long enough to generate electricity. Nuclear fusion requires very high energy and temperatures, so it is not a sustainable way to create electricity.

How Does Nuclear Energy Work? A Step-By-Step Guide

Inside a Nuclear Reactor

Nuclear reactors and their necessary equipment control the reactions that produce energy fueled by uranium-235.

The rods of uranium-235 are organized into linear arrays that are then immersed in a pressurized water tank. These fuel rods are changed out every 12 to 18 months to optimize power production.

A nuclear power plant uses uranium pellets to fuel a plant. As mentioned above, these pellets contain up to 3 percent of uranium-235. A large power plant could have as many as 13 million uranium pellets inside the reactor at one time. These pellets will remain inside the reactor for up to 4 years.

With a nuclear reactor up and running high-speed particles, neutrons strike uranium atoms, which causes them to split. During this process, energy is released, along with more neutrons, creating a chain reaction.

During a reaction, small atoms don’t require as much binding energy to hold them together, releasing the extra energy as heat and radiation.

The chain reaction of energy produced heats up water that is then piped out to a steam generator. Control rods are lowered into the reactor during this stage to prevent the plant from overheating.

A nuclear reactor is encased in a concrete barrier that prevents any radiation from escaping. This vessel is housed in a radiation shield liner followed by a containment structure to make sure communities are safe from radiation.

These barriers are also designed to withstand the impact of any possible accidents or major attacks.

Types of Nuclear Reactors

Pressurized Reactor

Inside a pressurized reactor or PWR, water is heated by a nuclear reaction. This water does not boil because it is pressurized. Instead, the water inside the reactor is used to heat the water inside the steam generator.

Since the reactor and the steam generator are on separate loops, the water contained in each never mixes.

Boiling Water Reactor

Inside a boiling water reactor or BWR, water is brought to a boil from the process of nuclear fission. This boiling water then powers a turbine.

how nuclear energy works

Steps to Generating Nuclear Energy

  1. A Chain Reaction is Triggered

A chain reaction that generates heat is triggered by neutrons fired at the uranium rods inside the reactor. This causes the neutrons to split, which releases more neutrons and thus continues the chain reaction.

  1. Water is Heated

The heat generated by the splitting of neutrons is used to heat water, which is passed through the reactor vessel and heated to around 570 degrees.

Since the water needs to remain in liquid form, a pressurizer inside the reactor applies around 155 times atmospheric pressure to keep the water from boiling.

  1. Hot Water Circulates

Next, a coolant pump circulates hot water from the reactor to the steam generator.

  1. Steam is Created

The pressurized hot water runs through thousands of looped pipes, while another stream of less-pressurized water flows around the outside of the looped pipes.

The water flowing around the outside of the pipes is under less pressure so it is easily boiled into steam.

  1. Steam Energy Converts to Electrical Energy

After the steam is generated, it is converted to electrical energy when the steam passes through a series of turbines, making the spin.

The turbines spin at 3,000 revs per minute, then convert the heat energy into mechanical energy using the steam generator.

Then the generator uses an electromagnetic field to convert mechanical energy into electrical energy.

  1. Electrical Energy is Funneled to National Grid

Electrical energy is then funneled to the national grid through a high-voltage transformer.

  1. Electricity Moves Through Power Lines

The national grid uses these high-voltage transformers to distribute energy efficiently through power lines.

This energy is then used to power homes, businesses, and other infrastructure. At this point, transformers reduce the voltage to a usable level.

  1. Steam is Cooled and Recycled

The final step in the nuclear energy production process is to cool the steam. To do this, the steam is passed over pipes full of cold seawater that has been pumped in.

The steam is cooled and condensed back into the water, in which the process of producing nuclear energy through nuclear fission continues in a chain reaction.

Advantages of Nuclear Energy

Now that you know how nuclear energy is produced, let’s talk about the advantages of producing and using nuclear energy for the power grid.

There are quite a few benefits of possessing nuclear energy capabilities.

Supports and Protects National Security

The United States government works closely with other countries to build relationships and develop opportunities for using the nation’s nuclear technologies for good.

Our country’s strong nuclear sector is essential to national security and international diplomacy.

The United States’ leadership in nuclear technologies helps maintain safety standards globally and supports a strong navy and a resilient electrical grid at home.

Fights Climate Change

Nuclear energy is the country’s largest clean energy source, generating nearly 800 billion kilowatt hours of electricity per year. This energy source is responsible for producing more than half of the country’s emissions-free electricity.

Nuclear power provides large quantities of constant carbon-free electric power, which is irreplaceable for fighting climate change and protecting the environment.

Reliably Produces Electricity for a Low Fuel Price

Nuclear energy is a critical part of the United States’ infrastructure, producing clean, reliable energy around the clock for up to 24 months at a time.

Uranium, which is found mostly in rocks, is used for power generation by nuclear power plants. This element is relatively cheap to mine and extract compared to other fuels, greatly reducing the cost of operating a nuclear power plant.

how nuclear energy works

Disadvantages of Nuclear Energy

While there are many advantages of nuclear energy, there are some disadvantages involved with producing and distributing the energy.

Radioactive Wastes

Despite being one of the cleanest methods of generating energy, a major disadvantage of nuclear energy is the radioactive waste it produces.

Radioactive nuclear waste is poisonous and toxic in nature. It contains harmful chemicals, like highly toxic plutonium, which only lose potency over several thousands of years.

Being exposed to these substances can cause cancer and other serious health conditions.

Unethical Use of Power

While nuclear power is an efficient and clean method for producing energy that can be converted to electricity, its misuse can have catastrophic implications.

Since the discovery of nuclear energy, there has been fear of the unethical and destructive purposes it could possibly serve. This technology can easily be manipulated and misused by nuclear-capable countries in the manufacturing of weapons that are extremely lethal in nature.

The gravity of misusing nuclear technologies can be observed through the senseless tragedy of lives lost and the lasting negative impacts of the nuclear attacks on Hiroshima and Nagasaki in 1945.

Nuclear Accidents

Accidents involving nuclear energy are extremely disastrous. Throughout history to date, 5 different countries have suffered 10 major nuclear disasters that left lasting impacts on human health and the environment.

You may recognize some of these nuclear accidents, such as the Chernobyl disaster, the Fukushima Daiichi disaster, and the Three Mile Island accident.

Due to these disasters and the resulting release of radiation, some countries, such as Japan, Russia, and Ukraine, were declared unfit for human livelihood at different times from 1957 to 2011.

The long-lasting impacts of these nuclear accidents are inferred from radioactive clouds that still float above the disaster sites. Exposure to these radioactive clouds’ radiation can result in life-threatening health conditions, such as cancer.

Building and Safety Costs for Nuclear Power Plants

A nuclear reactor, which is where the nuclear fission process will take place, must be built to the utmost perfection for the safety of everyone in surrounding areas.

The raw materials for building a nuclear reactor are astoundingly expensive, and the construction cost to build the power plant is through the roof.

With the implications of nuclear energy capabilities comes a huge responsibility – the security of the plant and the safety of employees and nearby inhabitants.

Since nuclear power in the wrong hands can be cataclysmic, security is vital. Employee safety measures must be strictly enforced at all times at a nuclear power plant.

A large chunk of the total fund granted for a nuclear power plant is assigned to the security of the plant and the safety of all those working or residing in homes nearby.

Frequently Asked Questions

how nuclear energy works

Is nuclear energy safe?

Using nuclear energy to generate electricity is generally considered very safe. A nuclear power plant is under stringent scrutiny to uphold strict safety standards.

Producing electricity using nuclear energy reduces the risks associated with the mining of fossil fuels for electricity.

How is nuclear energy used?

Nuclear energy is used to create electricity that powers a portion of the world’s infrastructure. Currently, 20 percent of the United States’ electricity is produced using nuclear energy. It is the largest source of clean energy in the nation.

It can also be used for diagnosis and treatment in modern medicine through nuclear medical imaging such as Magnetic Resonance Imaging or an MRI.

Nuclear energy is also used in space exploration, as well as criminal investigations, and to preserve food.

Is nuclear energy the cleanest form of energy?

Nuclear energy is a zero-emission clean energy source, so it is one of the cleanest forms of producing energy.

Using nuclear energy reduces harmful emissions created by the use of fossil fuel-powered energy. Nuclear energy has a small footprint, producing more electricity with less space than other energy sources.

Wrapping Up How Nuclear Energy Works

In the United States, as of 2022, there are 92 nuclear reactors operating at 54 power plants across the country. These power plants generate around 20 percent of the country’s electricity.

From atoms to electricity, nuclear power produces a clean and reliable source of electricity throughout the United States and around the world.

Check out our guide on surviving a nuclear attack to learn more about nuclear capabilities.