NRC Allows Duke Energy to Keep Some Nuclear Safety Details Secret

Federal regulators have agreed to keep certain technical information secret as Duke Energy seeks approval to update safety analysis methods for two nuclear power plants serving the Carolinas.

In a March 4 letter obtained by WCAB News, the U.S. Nuclear Regulatory Commission said proprietary information tied to Duke Energy’s request will be withheld from public disclosure under federal regulations governing confidential commercial data.

The request involves proposed updates to how the company analyzes a rare but serious scenario known as a control rod ejection accident at Catawba Nuclear Station near York, South Carolina, and McGuire Nuclear Station in Huntersville, North Carolina.

Control rods regulate the nuclear reaction inside a reactor. A rod ejection accident — considered extremely unlikely by safety officials — involves a control rod being rapidly expelled from the reactor core, potentially causing a sharp spike in power. Federal safety rules require utilities to model such events to ensure reactors remain within safe operating limits.

Duke Energy submitted a license amendment request in December, as we exclusively reported, asking the NRC to approve a revised technical methodology used to evaluate that type of accident. The update would align the company’s analysis with Regulatory Guide 1.236, issued by the NRC in 2020 to standardize how utilities model control rod ejection and similar events.

As part of the request, the company asked regulators to withhold certain engineering details from the public. Duke Energy argued the information reveals specialized analytical methods and design processes that could give competitors an advantage if released.

The NRC agreed, determining the material qualifies as proprietary under federal rules and the Atomic Energy Act of 1954. The agency said those portions of the filing will remain confidential.

For people living near the plants, the decision does not change plant operations or safety requirements. The NRC still reviews the full technical information — including the withheld portions — before deciding whether to approve the license amendment.

FEMA models various scenarios in coordination with local officials and is required to do routine training, as we exclusively reported. 

Nearly 285,000 people live within 10 miles of Duke Energy’s McGuire Nuclear Plant in Mecklenburg County, officials say. FEMA could not provide an exact number of people who might be impacted in the region outside of the 10-mile zone when this reporter asked during a briefing. 

The request also does not involve building new reactors or expanding operations. Instead, it updates the mathematical and engineering models used to evaluate potential accident scenarios.

Both Catawba and McGuire operate pressurized-water reactors and are among the largest electricity producers in the region, supplying power to millions of customers across North and South Carolina.

If approved, the revised methodology would simply update how Duke Energy performs certain safety analyses to align with current NRC guidance. Regulators said the information could be reconsidered for public release in the future if circumstances change or if requested under the Freedom of Information Act.