Decommissioning is a well-defined Nuclear Regulatory Commission (NRC) process for shutting down a nuclear power plant. It includes transferring the used fuel from the Duane Arnold Energy Center into safe, long-term storage. The overall process is gradual, and is expected to be complete by the year 2080.
What will decommissioning look like at the Duane Arnold Energy Center?
There are five aspects to the decommissioning process at Duane Arnold:
- The Duane Arnold Energy Center is scheduled to cease operations in the fall of 2020 after safely serving Eastern Iowa for 45 years.
- All fuel in the reactor is moved to the spent fuel pool to cool.
- Once cooled, the fuel will be placed in stainless steel canisters and transferred to concrete dry fuel storage modules on the property.
- The buildings on site will be demolished within 60 years. Waiting to demolish the buildings allows any remaining radioactivity to decay, making the demolition process more environmentally and economically responsible.
- The site will continue to be protected and monitored by highly trained staff and examined by state and federal agencies.
What happens to the nuclear material on site?
The used fuel will be placed in long-term dry storage on site within three years of the plant shutting down.
The reactor building has accumulated some residual radioactive particles over the life of the plant. The buildings will remain vacant for 50 years before being demolished. The eventual demolition of the reactor building will be conducted with care and respect for the surrounding environment. Any other buildings remaining on the site will also be demolished at this time.
Why are you waiting so long to demolish the buildings?
While the Duane Arnold Energy Center is a very clean facility, the equipment used over the lifetime of the plant has residual radioactive particles. By maintaining the buildings, we allow time for the natural processes to reduce the intensity of the radioactive particles. When the time comes to take buildings down, it will be easier on the environment and more economical to remove material from the site.
The site will continue to be protected by a security force and monitored for any possible environmental impacts until all spent fuel is removed from the site.
NextEra Energy Resources believes it's important to operate its business in harmony with the environment and our neighbors. We take our responsibility to see that the site is maintained in a way that benefits the long term health of the community very seriously. We will continue to work with the NRC until the decommissioning process is complete.
Is it possible to have an emergency at the site after shut-down?
After the plant shuts down, the possibilities for an emergency decrease dramatically. The Duane Arnold Energy Center will maintain capabilities to address any possibility of an emergency at the plant, no matter how unlikely, until all fuel has been placed in long-term storage. Once all the used fuel has been placed in long-term storage, the risk of an emergency that could affect the community is virtually eliminated. However a security force will remain to protect the facility.
Who pays for decommissioning?
NextEra Energy Resources will pay for Duane Arnold’s decommissioning. Nuclear power plants are required by the NRC to put aside funds for decommissioning while the plant is operating. The money is invested in dedicated trusts over the lifetime of the plant. The fund distribution is carefully monitored by a third party. NextEra Energy Resources estimates the decommissioning of Duane Arnold is fully funded.
Safety is Duane Arnold’s number one priority, and that includes a responsibility to safely and securely store the spent fuel we create. We have worked with experts to develop safe, secure, environmentally sensitive used fuel storage methods that go above and beyond government requirements.
- Once plant operations cease, all fuel in the reactor is moved into temporary storage inside the reactor building called the spent fuel pool.
- The pool is constructed of steel-lined concrete with water constantly circulating around the used fuel as it continues to deplete its concentration of radioactive elements.
- The spent fuel pool is constantly monitored using a variety of methods to maintain proper cooling.
Within three years of the Duane Arnold Energy Center shutting down, all used fuel will be housed in long-term dry storage.
The dry fuel storage process
- A sturdy stainless-steel canister is loaded into a metal transfer cask and placed in the spent fuel pool. Spent fuel is then loaded into the canister. A lid is placed on the canister and the transfer cask, with all its contents, is removed from the spent fuel pool.
- After moving to a separate building, the canister lid is welded in place and the water is drained from the canister. Then, the canister is dried, sealed, and inspected.
- The transfer cask, with the sealed canister inside, is placed on a trailer and transported to the dry storage site, which is located inside the plant's security area.
- The canister is loaded into a dry storage module, surrounded on all sides with two to four feet of steel-reinforced concrete.
The dry storage facility at Duane Arnold is specially designed and tested to meet all US Government requirements, including protection from extreme natural events such as tornadoes, fires, flooding and earthquakes. The facility itself is heavily secured and includes multiple layers of protection, including perimeter fencing, radiation monitoring, a vehicle barrier system, a high-tech perimeter intrusion detection system, continuous surveillance, and regular security patrols. Security measures also fall under the strict regulatory oversight of the NRC.
In the United States, the U.S. Department of Energy (DOE) holds the ultimate legal responsibility for the disposal of used nuclear fuel. However, the approval and construction of a federal waste disposal site is years behind schedule. The spent fuel from the Duane Arnold Energy Center will continue to be safely stored onsite until the DOE is able to receive the fuel.