Storm damage prompts NextEra Energy to shut Duane Arnold nuclear plant early

New York — NextEra Energy Resources will not restart the reactor at the Duane Arnold Energy Center in Iowa before it is permanently decommissioned, the company said Aug. 25.

The 622-MW nuclear plant has been shut since Aug. 10, when high winds from a powerful storm system known as a derecho damaged the plant's cooling towers and caused it to lose its off-site power source, resulting in an automatic shutdown. The plant, which is operated and mostly owned by the NextEra Energy subsidiary, had previously been scheduled for permanent closure on Oct. 30.

NextEra Energy Resources said in a statement Aug. 25 that it had made the decision not to restart the reactor after an assessment of the storm damage.

"The strong storms that hit the area on Aug. 10 caused extensive damage to Duane Arnold's cooling towers, and our evaluation found that replacing those towers before the site's previously-scheduled decommissioning on Oct. 30, 2020, was not feasible," the company said.

NextEra Energy Resources also said it will continue to work with employees to "minimize the impact of this situation on them and their families."

The plant, located in Linn County, Iowa, started operating in 1975 and had a renewed license allowing it to operate until 2034. However, NextEra Energy Resources in 2018 moved up the retirement date, following a deal to shorten Alliant Energy subsidiary Interstate Power & Light's power purchase agreement for the output of the plant. That contract is set to end in October, S&P Global Market Intelligence data shows.

A representative with the utility did not immediately return a request for comment Aug. 25 about what, if any, effect Duane Arnold's early closure would have. As part of the 2018 agreement to shut the plant, NextEra said it would provide Alliant with 340 MW from repowered wind farms in Iowa.

NextEra submitted a letter to the US Nuclear Regulatory Commission March 2 "certifying plans to cease operation" of Duane Arnold Oct. 30, NRC Region III spokeswoman Viktoria Mitlyng said Aug. 25. "If NextEra makes the business decision to change this date, the company would have to notify the NRC in writing of this change in plans," but the agency "has not received an official update" from NextEra, Mitlyng said. "Changing this date requires notification, but not approval by the NRC," she noted.

According to Market Intelligence data, Central Iowa Power Cooperative owns a 20% share of the plant, while Corn Belt Power Cooperative owns the remaining 10%.