About Nuclear Energy

What is Nuclear Energy

Nuclear energy is the energy released from the nucleus, the dense center of an atom, which contains protons and neutrons.

This energy can be harnessed in 2 ways:

Fission

where atomic nuclei split apart

Fusion

Where they combine

Today’s nuclear power plants use fission to generate electricity. In this process, uranium atoms are split in a controlled reaction inside a reactor, releasing heat. All without emitting greenhouse gases.

How a Nuclear Reactor Works

The primary job of a nuclear reactor is to safely house and control the nuclear fission process.

Hundreds of uranium fuel assemblies make up the reactor core. Inside the reactor vessel, the fuel rods are submerged in water which acts as both a coolant and moderator.

To control the reaction control rods are inserted or removed into the reactor core. Inserting the rods reduces the reaction rate and withdrawn increase the reaction rate.

The heat created by fission turns the water into steam, which spins a turbine to produce electricity.

Inside the reactor core:

Fuel rods undergo controlled chain reactions

This releases heat

That heat turns water into steam

Steam spins a turbine connected to a generator

This produces electricity

There are 2 main types of commercial reactors:

Pressurized Water Reactors (PWRs)

Water is kept under pressure and steam is produced in a separate loop.

Boiling Water Reactors (BWRs)

Water boils directly inside the reactor vessel and the resulting steam drives the turbine.

Both reactor designs include multiple safety systems to ensure stable performance, reliable operations and carbon-free electricity generation. Columbia Generating Station uses a BWR system.

Learn more about how Columbia Generating Station produces power

Nuclear Fuel

Nuclear fuel starts with uranium, a naturally occurring metal processed into small ceramic pellets.

These pellets are:

  • Stacked into long metal tubes called fuel rods
  • Bundled together into fuel assemblies

After several years:

  • The fuel is considered “spent”
  • It is removed from the reactor
  • It is cooled in specially designed pools
  • Then safely stored in secure, above-ground containers

Spent nuclear fuel is:

  • Highly regulated
  • Safely managed
  • Fundamentally different from the waste produced by weapons programs

Nuclear Energy Facts

Carbon-Free Power

Nuclear energy produces electricity without emitting greenhouse gases. It’s the largest source of carbon-free electricity in the U.S., supplying nearly 20% of the nation’s power.

Always On

Nuclear plants operate  24 hours, 7 days a week, providing a steady and reliable source of electricity regardless of weather or time of day.

Energy Density

A single uranium fuel pellet, about the size of a gummy bear—can produce as much energy as one ton of coal, 149 gallons of oil, or 17,000 cubic feet of natural gas.

Supports Daily Life

Nuclear-generated electricity powers everything from home appliances and HVAC systems to hospitals, schools, and electric vehicles. It keeps MRI machines running, classrooms lit, and online learning platforms connected.

Safe and Secure

U.S. nuclear plants are among the most heavily regulated industrial facilities in the world. They are designed with multiple safety systems and are built to withstand extreme conditions.

Minimal Waste

All the used nuclear fuel produced in the U.S. over the past 60 years would fit on a single football field stacked about  30 feet high. It is safely stored and strictly regulated.

Learn More About Our Nuclear Projects

Extended Power Uprate (EPU)

Discover how we’re increasing Columbia Generating Station’s output by 20% to meet growing energy needs while maintaining safety and reliability.

Rendering of Energy Northwest's Cascade Advanced Energy Facility

Cascade Advanced Energy Facility

Learn how we’re partnering with Amazon and X-energy to bring advanced small modular reactors (SMRs) to Washington—offering flexible, carbon-free energy for the future.

Powering a Clean Energy Future

Watch our short video (YouTube) to see how Columbia Generating Station supports the region with safe, reliable, carbon-free electricity.