This is part two of a series on the steps in the fuel life cycle at Duke Energy’s nuclear power plants. To learn about how uranium makes it way to our power plants, read part one.
By the time a single uranium fuel pellet makes its way to a nuclear power plant, it’s already had an exciting life, but that’s only half of its story. Let’s learn about the next stage in its life cycle.
Step 6. Fuel assemblies are arranged and loaded into the nuclear reactor during a scheduled refueling and maintenance outage. Keep in mind that during outages, only one-third of the fuel in the reactor needs to be replaced. The remaining fuel will be rearranged. How each fuel assembly is placed in the reactor depends on how it interacts with other assemblies to ensure it generates the appropriate amount of heat. You can learn about one member of the talented team of engineers that determine the arrangement of reactor cores (fuel) in this article.
Step 7. The reactor is reassembled with the new fuel and a new arrangement and starts up for an operating cycle. Inside the core, the nuclear fuel does its job of generating heat used for making clean, life-essential electricity around the clock to power the lives of our communities. For nuclear plants, an operating cycle lasts for 18- to 24-months. At the end of the cycle, the plant will once again enter a refueling outage.
Step 8. After generating heat for about four years in the reactor, fuel assemblies are ready for wet storage. Used fuel that can no longer generate heat needed to make electricity is removed from the reactor and carefully transported to a used fuel pool. This used fuel pool is a steel-lined, concrete pool filled with water. Water both cools the fuel and shields workers from any radiation in the fuel storage area.
Step 9. After cooling in the used fuel pool for several years, nuclear fuel is ready for transition to dry fuel storage. This effort – called a dry fuel storage campaign – requires detailed planning and careful coordination, much like a refueling and maintenance outage. Workers load the fuel assemblies into large, steel-lined concrete containers that are welded air-tight and can withstand extreme physical forces, such as tornadoes. These containers are moved from the used fuel pool area to another on-site, secure location for long-term storage.
Watch and learn the intricate process for steps 8 and 9 in this video as used fuel is removed from the reactor and dry fuel storage campaign operations are conducted at Catawba Nuclear Station.
From its start as mined uranium ore to its peak as a nuclear fuel pellet powering our communities, the nuclear fuel journey is an essential part of how our reactors operate. As the world focuses on cleaner generation, stay tuned for what might be the next chapter in the nuclear fuel story.