The ABCs of nuclear energy

Editor's Note: This story was updated Nov. 5, 2019.

While nuclear energy is not nearly as simple as learning our ABCs, it’s not as mysterious as you might think. In honor of Nuclear Science Week, we’re breaking down some common nuclear energy concepts to help you learn more about it.

A is for atom. Atoms are the smallest particle of an element that can’t be broken up by chemical means. Nuclear plants split atoms to make electricity. That’s why nuclear energy is sometimes referred to as atomic energy.

B is for baseload. Some power plants, like nuclear energy facilities, are designed to run at or near full capacity around-the-clock to provide power to the electric grid at all times. This allows us to turn on a light or use an appliance any time of the day.

C is for capacity factor. Capacity factor is a measure of reliability. It’s the amount of electricity a power plant provides versus the maximum that could be produced around-the-clock. U.S. nuclear plants have a very high capacity factor, an average of more than 92%.

D is for dry cask storage. After used nuclear fuel has been cooled in used fuel pools, it’s sealed in steel-lined, concrete containers called casks and safety and securely stored on concrete pads.

E is for emergency preparedness. All six of our nuclear plants have designated Emergency Planning Zones (EPZs), areas within 10 miles of the plant used for emergency planning.

F is for fission. Fission is the process of splitting atoms, which releases tremendous amounts of energy in the form of heat. Nuclear plants use heat from fission to produce electricity.

G is for generator. Like other power plants, nuclear facilities use generators to convert mechanical electricity (usually from a

turbine) into electricity.

H is for half-life. Some forms of an element (like Uranium235) are radioisotopes, meaning they emit radiation as they try to reach a more stable state. This happens over a defined period of time called a half-life. Specifically, a half-life is the time it takes for half of the atoms of a particular radioisotope to transform into another form of the element.  

I is for ionizing radiation. There are many forms of radiation. Ionizing radiation can lead to changes in living cells. It has many beneficial uses, such as treating cancer, but can also be harmful if not used correctly. The Nuclear Regulatory Commission regulates commercial and institutional uses of ionizing radiation, including at nuclear power plants.

J is for jobs. Our nuclear fleet provides more than 5,000 well-paying jobs and careers in a variety of fields: operations, maintenance, security, engineering and more.

K is for kilowatt-hour (kWh). A kWh is a unit of electricity equivalent to using one kilowatt of power for one hour. The average American home uses 900 kWh of electricity per month.

L is for lake water. Nuclear power plants use water from lakes, rivers or reservoirs to cool the steam used to generate electricity. The cooling water remains in a separate system and does not come in contact with the nuclear fuel.

M is for megawatt. Our nuclear fleet can generate about 10,700 megawatts – enough electricity to power 7 million homes.

N is for Nuclear Regulatory Commission (NRC). The NRC regulates commercial nuclear power plants and other uses of nuclear materials, such as in nuclear medicine, through licensing, inspection and enforcement.

O is for outage. Every 18-24 months, nuclear plants temporarily shut down for refueling and maintenance. By combining many activities, these planned outages make our nuclear fleet even more efficient.

P is for pellet. Nuclear fuel comes in the form of solid cylinders of uranium, about the size of a pencil eraser. These pellets are stacked in rods that form assemblies and are placed in the nuclear reactor.

R is for reactor. A steel vessel that contains the core – where fission takes place – among other things. Nuclear reactors are surrounded by steel-lined, airtight concrete containment buildings. 

S is for safety. The nuclear energy industry is one of the safest and most secure in the country. Nuclear plants use multiple, redundant safety systems to protect plant workers and the public, including physical barriers and routinely practiced emergency plans and procedures.

T is for turbine. Like other power plants, nuclear facilities use steam to spin a turbine – which looks like a large fan – to drive a generator to

make electricity.

U is for Uranium235. Duke Energy’s nuclear reactors use Uranium235 for fuel because its atoms can easily split or fission.

W is for water vapor. The “cloud” seen leaving the top of the cooling towers at some of our nuclear plants is not smoke – it’s clean water vapor. It comes from the cooling process.

Z is for zero emissions. Emissions are substances, especially pollutants, released into the air. Nuclear power plants emit no greenhouse gases when producing electricity.