Duane Arnold transfers spent fuel into permanent storage facility

NextEra’s Duane Arnold Energy Center has completed a major step in decommissioning the closed nuclear power plant near Palo, transferring spent fuel into a permanent on-site storage facility in record time

Iowa’s only nuclear plant was set to start the decommissioning process in October 2020 but was shut down early after being damaged in the Aug. 10, 2020, derecho.

Dozens of the plant’s team members transferred spent fuel into a spent fuel storage installation at the plant in 20 months. The previous industry record was 30 months last October at the Pilgrim Nuclear Power Station in Plymouth, Mass.

The decommissioning project had an original estimated timeline of between three to five years from plant shutdown to completion of transferring the fuel. The process included more than 1,800 fuel assemblies moved into 30 stainless-steel containers. Each canister holds 61 fuel assemblies and stands approximately 18 feet tall.

Megan Murphy Salyer, the lead communications specialist at NextEra, said the process was sped up in part due to new cask designs for holding the spent fuel. The process saved $100 million, she said.

“We also chose to keep the work mostly in house so we were able to leverage our own experts and that really helped us move smoothly through the process,” Murphy Salyer said.

The spent fuel is stored onsite in a dry-storage container, which is basically a concrete bunker. Previously, while the plant was in operation, the fuel was in a spent-fuel pool. To move it into storage, the team put a cask underwater and moved fuel bundles from the pool into the cask. The water was drained and the cask was filled with inert gas and sealed, and put into another cask that’s used for the transport, Murphy Salyer said.

The waste will stay in the storage facility indefinitely unless there is another place to put it in the future. Currently the United States does not have a long-term storage facility for nuclear materials.

“That is never ending until there is another place to put it,” Murphy Salyer said. “I would say (The Department of Energy) is not at a place where there is a timeline for a long-term storage facility.”

However, Murphy Salyer said that since the spent fuel is now being stored and the plant is no longer operating, the risk off an airborne release is zero percent.

“There’s no risk to the public at this time,” she said. “When we were an operating facility, we maintained a very robust emergency response organization that was ready to work with the local communities to address any emergency that might happen within a 10 to 50 mile radius at the plant.”

With the fuel now being in long-term storage, the 10 to 50 mile radius is no longer in effect, Murphy Salyer added.

There are still a few systems inside the plant that need to go through the final stages of decommissioning, but for the most part the plant will maintain staff to monitor and protect the long-term storage facility. The facility itself will sit empty with monitoring for approximately 50 years before being demolished.

All structures on the site will be removed by 2080 to allow time to reduce the intensity of radioactive particles.

Later this month, over 60 employees will be let go from Duane Arnold under its plan to draw down staff at the closed plant. The plant had about 500 employees before being closed.

Duane Arnold eliminated 128 positions a month after closing, according to a notice filed with Iowa Workforce Development, and eliminated another 47 jobs last June. According to the latest notice from March, 61 employees will work their last day May 13.

By the end of 2022, about 50 employees will be at the site for the long term, Murphy Salyer said.

In the meantime, NextEra is preparing for the Linn County process of approving its application for a utility-scale solar projects called Duane Arnold I and II.

Duane Arnold Solar I would use 316 acres of an 857-acre area to place photovoltaic solar arrays capable of generating up to 50 megawatts of energy. Duane Arnold Solar II would use 815 acres of a 1,780-acre area to place solar arrays capable of generating up to 150 MW, as well as a 75-MW, four-hour battery energy storage facility.

If approved by the county and state, the project would begin operation by the end of 2024. If everything is approved, the plan would be for NextEra to develop and construct the project, but once operational, Alliant Energy would own and operate the project.

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